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A comparison of a diesel engine (compression, left), petrol engine (spark, middle), and HCCI engine (compression, right). The HCCI engine is at least as efficient as diesel, and perhaps can be even more so.  (Source: Berkley.edu)

Another comparison, with traditional spark injection on the left, and the more efficient HCCI engine's compression burn on the right.  (Source: GM)

GM's new HCCI engine should deliver top-tier performance and fuel economy, and help lay to rest the diesel versus hybrid debate.  (Source: GM)

The 2010 Buick Lacrosse is among GM's many new models to feature gasoline direct injection. The HCCI engine technology, likewise, could soon be bringing even greater efficiency to the GM lineup.  (Source: AutoBlog)
GM hopes to finally lay to rest the diesel versus hybrid debate with its diesel-like new gas engine

There has been a reoccurring debate over the merits of diesel vehicles versus hybrid ones.  Both technologies help to increase fuel economy; however, people tend to be convinced that the one or the other is the only solution to these problems.

Now GM finally is preparing to lay these criticisms to rest with potentially the first compression-ignited gas engines to see rigorous real world testing, in preparation of market entry.

In order to understand why this is so significant, a discussion of engines is in order.  Diesel engines typically have two advantages over their gasoline burning counterparts.  The first is direct injection.  Traditional gas engines inject fuel into an intake, and the air-gas mix is then sucked into chamber, compressed, and finally ignited.  Diesel engines put it directly into the combustion chamber, a more efficient process.  This problem has already been tackled by Ford (EcoBoost), GM and many others, and direct-injection gas engines will soon be all over the market.

The second diesel advantage is compression ignition.  In a diesel engine, the compression of the gas/air mix triggers ignition, and the compression causes the combustion to be evenly distributed.  In a traditional gasoline engine, compression is limited by design so less-efficient spark ignition must be used.  This problem has yet to be solved in a production model.

GM's HCCI (homogenous charge compression ignition) four-cylinder engine unveiled at the company's research and development center this week may be the first engine to bring compression to the world of gas engines.  In early testing the engine deliver 15 percent better fuel economy and much lower NOx gas and CO2 emissions.

Uwe Grebe, GM's executive director of powertrain advanced engineering, says that the new engine greatly reduces these toxic gases.  He says that the technology can easily "be applied to many engines, including four- , six- and eight-cylinder engines."

The secret to the new engine is temperature control. Typically an engine runs at 3,800 degrees Fahrenheit, but the new engine runs from 0 to 60 mph and from idle to 3,000 rpm at 2,900 degrees Fahrenheit (ignition temperature).  This means that there are fewer pollutants, and compression can be used to ignite the fuel without risking damage to the engine.  Essentially this yields a gas-burning engine that runs as clean and efficiently as a diesel.

Vijay Ramappan, staff engineer for calibration, states, "From zero to 60, this engine can run completely in HCCI mode and basically work like a diesel."

GM is not revealing when the engine might see production deployments, or if it will utilize GM's direct injection gas technology to offer even greater benefits, a likely move.  Whenever the engine does see the market, though, it would make a dynamite partner to a hybrid powertrain, possibly delivering a gasoline-sipping engine with potential performance well north of 100 mpg in small cars.



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"Can be used up to 60mph"
By Aquila76 on 5/21/2009 1:25:57 PM , Rating: 1
OK, so what happens after you hit 60MPH? Almost every highway here is 65, and if you drive 60 on any highway, you'll be rear-ended or honked at constantly.




RE: "Can be used up to 60mph"
By robertisaar on 5/21/2009 1:33:37 PM , Rating: 4
it almost sounds as if there is a rev limit at 3000RPM for the HCCI cycle, so i imagine after that it would revert to traditional fuel injection.

diesel's redline are determined by exhaust gas temperature, and is usually around 3000RPM, so it seems likely that should the motor pass 3000RPM, it will just switch modes.


RE: "Can be used up to 60mph"
By JasonMick (blog) on 5/21/2009 1:42:10 PM , Rating: 5
Correct, the engine is still capable of traditional spark ignition as well. It should basically get great performance up to 60 mph, then get relatively good performance at fuel-efficient highway speeds (above 60 mph).

Direct injection or electric assist, if used, might still be usable at higher speeds, too.

And again, this is just an early version -- as time goes, I'm sure they'll be able to push that envelope higher. If they could get it up to 80 mph and 4000 rpm, that would cover most normal use. Unless you like to get to work *REALLY* fast ;-)


RE: "Can be used up to 60mph"
By codeThug on 5/21/2009 2:57:01 PM , Rating: 3
Not to sound like a smart @$$, but is this some of the technology and science that Detroit and the Oil companies have been sitting on for years, or actually something new?


RE: "Can be used up to 60mph"
By codeThug on 5/21/2009 3:17:42 PM , Rating: 3
Down modding doesn't answer the question.

It simply exemplifies the ignorance on DT.

This question has nothing to do with Jason. I actually like the article. I just want to know how long this tech has been on the drawing board. I would guess much longer than most people realize.


RE: "Can be used up to 60mph"
By DigitalFreak on 5/21/2009 3:52:25 PM , Rating: 3
Direct injection gas engines have been around for awhile. However, they've been relegated to higher end vehicles (on option on the Cadillac CTS, for example). Don't know about compression ignition in non-diesel engines though.


RE: "Can be used up to 60mph"
By 67STANG on 5/21/2009 5:02:28 PM , Rating: 4
2.3L DISI from Mazda has been around since 2007 I believe? I know they have been using it in the Mazdaspeed 3.

If I'm not mistaken, this is where Ford got their design for the DI in the EcoBoost engines. (as they still have a small stake in the Mazda).

The reason DI is coming to fruition now, rather than 30 years ago, is because it would have only served the purpose of lowering emissions back then, somthing that was curbed by catalytic converters-- for much less money. In the end, that's what it all came down to, dollars and cents.


RE: "Can be used up to 60mph"
By Souka on 5/21/2009 6:44:51 PM , Rating: 2
It would be very nice if they'd figure out solenoid acutated valves for IC engines...that would be a very nice boost to engine fuel economy and durabilty (fewer parts).

A solenoid valve would generate a near square pattern for the valve...which allows for maxinum open time for air/fuel to enter, unlike the sine-wave pattern of typical valves.

Last I knew (years ago)they hadn't.

oh..here's a blurb from Fiat... http://www.greencarcongress.com/2009/03/fiat-intro...


RE: "Can be used up to 60mph"
By v1001 on 5/21/2009 8:07:57 PM , Rating: 2
When this baby hits 60 Miles per hour you're going to see some serious sh**


RE: "Can be used up to 60mph"
By Amiga500 on 5/22/2009 4:01:37 AM , Rating: 2
Check the Renault F1 engine... they were looking into solenoid valves a number of years ago (2001?).

Dunno if it ever came to fruition though.


RE: "Can be used up to 60mph"
By Souka on 5/22/2009 4:58:50 PM , Rating: 2
HEh..yeah...sure... I"ll put one in a lowered honda civic...

http://www.youtube.com/watch?v=Eo-9Io41bt8


RE: "Can be used up to 60mph"
By dav115 on 5/23/2009 10:00:40 AM , Rating: 2
Mmm not quite sure about your civic, perhaps something just a little bigger though...http://www.youtube.com/watch?v=eaW_35KPDBY . On a side note, have a read of the 4th and 5th paragraphs in this link: http://www.fiat.co.uk/Content/?id=10857 . I think this engine is due to be rolled out for the 500 in the near future.


RE: "Can be used up to 60mph"
By amagriva on 5/23/2009 5:17:30 AM , Rating: 2
"old and at least credit me..."

watch the video
By amagriva on 4/29/2009 5:24:04 AM , Rating: 2
http://www.motori.it/tecnica/516/arriva-il-multiai...


RE: "Can be used up to 60mph"
By invidious on 5/21/2009 4:11:55 PM , Rating: 2
If you want enlightened answers don't ask loaded questions. Your question assumes that the oil companies are evil, and addressing that is going to derail the thread.


RE: "Can be used up to 60mph"
By mindless1 on 5/21/2009 4:46:36 PM , Rating: 4
No, the question assumes an oil company has no incentive to reduce the public's consumption of fuel, the same as most companies not looking for ways their customers will buy less. Whether their wanting to retain profit levels is evil or not was your own addition to the topic.


RE: "Can be used up to 60mph"
By Samus on 5/21/2009 5:31:19 PM , Rating: 2
Direct Injection has been around since the 70's, as every deisel engine using at least mechanical direct injection.


RE: "Can be used up to 60mph"
By codeThug on 5/21/2009 5:17:34 PM , Rating: 2
Point taken.

However, given the length of time the internal combustion engine has been with us, along with the size of the industry (both auto and oil), it seems almost a given that things would be ripe for manipulation. Even though the original question might have seemed a tad trollish, the supposition of industry interference is not a new one.

http://en.wikipedia.org/wiki/General_Motors_street...

Nobody walks in LA...


RE: "Can be used up to 60mph"
By ArcliteHawaii on 5/21/2009 6:25:07 PM , Rating: 5
I don't know about this technology particularly, but here are a couple of points.

1. The idea that the oil company has been buying up patents for 200 mpg carburetors and other fuel efficient technologies has been debunked. If such things existed, countries like China would be ignoring patents and using them anyway.

2. The idea that a car company would just sit on or sell to the oil companies technology that would give it an advantage over its rivals doesn't make sense. In this particular case, I think that high gas prices have necessitated this research, and that's why we're finally seeing this technology. Also, this probably wasn't some thing that could be done without a computer controlled engine.


RE: "Can be used up to 60mph"
By Regs on 5/21/2009 8:09:15 PM , Rating: 2
At a business stand point right now, I think of it as any one of us going to a bank with a business proposal to get qualified for a loan. Since GM is "owned" or being payed by the tax payers, I think this is GM's way of asking for a loan. Make it public - make everything public. If we're going to pay their way out of debt, I think they owe us that much consideration.


RE: "Can be used up to 60mph"
By bill3 on 5/23/2009 9:19:47 AM , Rating: 1
High gas prices have NOTHING to do with it. Left wing regulations/laws in the name of bullshit environmental pseudo-science (that will harm the environment and kill who knows how many of starvation in the end) do. In this case, CAFE standard that cars are going to have to average 42 MPG by 2016.

This isn't voluntary, and it isn't market driven. If car companies dont do this, people with guns (miltary/police) will come and shut them down with force. It's the law.

Of course, the government now owns 2 out of the 3 car companies anyway, so it's not like theres anybody to resist anymore even if they wanted to.


RE: "Can be used up to 60mph"
By bill3 on 5/23/2009 9:38:18 AM , Rating: 2
And you know its interesting, the "high price of gas", I just checked and according to this website I found the price of a gallon of gas was 1.20 in 1985.

Now, I was 10 years old that year, but I dont remember specifically how much gas was every year, but that sounds about right.

Anyway, if you take a generally accepted inflation figure such as 3% per year, and do the math, you find that 1.20 in 1985 is the same value as 2.37 today. Which were I live is about what a gallon of gas costs (actually 2.17 for 87 octane I believe last I filled up). The same way I remember candybars used to cost 33 cents, and now theyre often 99 cents. (My parents told me when I was a kid of when they were 5 cents!).

Of course there's all types of caveats here. For one, the price of gas in 1999 was still around 1.20 a gallon. Of course that doesnt mean gas is expensive now, just that it was relatively cheaper in 99 than 85. But I dont think there was great consternation in 85 over the price of gas as there is today, even though in real dollars it was similar.

Not only that but 3% is probably a very low number for inflation, any gold standard will tell you, the government pumps new money into the supply at a rate of more like 12% per year, etc etc. Anyway. As I said, there's tons of caveats on all sides, but the point stands, gas isn't more expensive today than it was in 1985 (in real terms adjusted for REAL inflation, it's probably a lot lower). Not even mentioning the fact that gas today is artificially priced higher because of countless left wing regulations (this time of year for example, it goes up because of increased ethanol requirments implemented in the last few years by the left, which studies have also shown ethanol harms the environment).


RE: "Can be used up to 60mph"
By nbourbaki on 5/24/2009 2:04:02 PM , Rating: 3
I just wanted to make sure I understand the point of view. Right Wing has no interest in clean air and are forced to breath cleaner air because of the left wing?

I believe the context of High price of gas was a year or so ago when a gallon of gas started hitting $5.00 a gallon for regular. The only reason the price of gas is back down to average numbers is because the 1st world is in the middle of a severe recession. As the recession wanes, you'll see the price of gas go back up and exceed $5.00 a gallon.

I personally believe that the high price of gas during this timeframe was a catalyst for the recession we are currently in.


RE: "Can be used up to 60mph"
By ArcliteHawaii on 5/26/2009 4:17:53 PM , Rating: 2
The high price of gas was a large factor. People had their gas bills essentially double, and that meant less money to pay the mortgage, thus the increase in foreclosures. You can't halve your driving, no matter how hard you try when you live in the suburbs, where the majority of foreclosures are occurring.


RE: "Can be used up to 60mph"
By EDL on 5/27/2009 1:18:38 PM , Rating: 2
What I wonder is how stupid do the oil companies think we are? They claim supply/demand reasons for raising prices, they claim "uncertainty" about <insert some random event here> and raise prices. They claim it's costing them more so they have ot raise prices. OMG! the CEO stubbed his toe! Raise gas prices! Etc, etc ad nauseum.

All this and then companies like Exxon/Mobile post back to back record profits (i.e. real profit, after operating costs are subtracted) exceeding 45 billion dollars.

I thought price gouging was illegal, apparently it is except for the oil companies.

Maybe it's time for the government to regulate the oil companies like they did the phone compoanies and electric companies....oh wait, the electric companies are not going to be regulated soon. We've already been told to expect 40%+ increases in electricity prices. Weeeehaaaa.


RE: "Can be used up to 60mph"
By ksherman on 5/21/2009 5:21:54 PM , Rating: 2
This has nothing to do with Direct Injection.


RE: "Can be used up to 60mph"
By joeindian1551 on 5/21/2009 9:45:45 PM , Rating: 2
HCCI has been around since the late 70s but no one has been able to get it into production form. Popular Mechanics ran a story on it quite a while back and detailed some of the issues the car companies have had trying to build a production quality engine.
http://www.popularmechanics.com/automotive/new_car...


By AlexandertheBlue on 5/24/2009 12:42:35 PM , Rating: 2
Honda had something similar around 15 years ago, however despite a successful test in the granada-dakar rally, it never reached production.

http://dwolsten.tripod.com/articles/jan97.html

I won't claim to know why. However cost, reliability and regulatory factors usually contribute to something like this 'dieing on the vine' so to speak


RE: "Can be used up to 60mph"
By wookie1 on 5/21/2009 7:08:03 PM , Rating: 2
I'm not sure how they can switch to spark ignition unless they can also lower the compression ratio somehow.


RE: "Can be used up to 60mph"
By Keeir on 5/21/2009 7:32:58 PM , Rating: 1
quote:
I'm not sure how they can switch to spark ignition unless they can also lower the compression ratio somehow.


Pretty simple. Lower the amount of air that is allowed into the cyclinder.... In practice, I imagine this is a bit more complex as I image you must have different gears for the CAM shafts or something similar.


RE: "Can be used up to 60mph"
By Iaiken on 5/27/2009 3:41:16 PM , Rating: 2
That is more of a transmission problem, one that can be easily remedied with the use of a long-legged gearbox.

A 1.6L Tritech on a 6-speed getrag can hit 80MPH@3000RPM with ease. Forced induction versions of the engine can easily hit 90MPH@3000.

Somehow I don't think this is going to be much of a problem so long as the displacement/gearbox combination produces a suitable level of performance for the vehicles size.


RE: "Can be used up to 60mph"
By FITCamaro on 5/21/2009 1:50:33 PM , Rating: 5
Most diesels redline around 5500 rpm.


RE: "Can be used up to 60mph"
By Lord 666 on 5/21/2009 2:53:23 PM , Rating: 3
Why rate him down for this? The redline on my 2006 TDI is 4500.


RE: "Can be used up to 60mph"
By fotoguy on 5/22/2009 9:15:09 AM , Rating: 2
Sorry for the tangent, but are there DT moderators that come along and change the ratings of posts?


RE: "Can be used up to 60mph"
By Keeir on 5/22/2009 11:32:40 AM , Rating: 2
quote:
Sorry for the tangent, but are there DT moderators that come along and change the ratings of posts?


Register Users who have acquire some level of experience can changede the rating of posts. Only when they have not made a comment to the article.


RE: "Can be used up to 60mph"
By Kaldor on 5/21/2009 4:36:28 PM , Rating: 5
Depends largely on the motor. The larger the engine, the lower the redline. Powerstroke redlines a little over 4k. Larger diesels are around 2k.

This has largely to do with the reciprocating mass of the motor.


RE: "Can be used up to 60mph"
By Lord 666 on 5/21/2009 4:47:45 PM , Rating: 2
Redline on the VW Toureg V10 5.0 TDI is also 4500rpm as the 1.9.

This is actually exactly the vehicle I have been looking to purchase. Original retail price was 70,000, but now is in the low 30,000s. Don't really care if it requires 14 quarts of synthetic for an oil change, it has over 500lbs of torque and drives like a amazing. Gets about 30mpg on the highway.

http://cgi.ebay.com/ebaymotors/2006-VOLKSWAGEN-TOU...


RE: "Can be used up to 60mph"
By ExarKun333 on 5/21/2009 5:08:24 PM , Rating: 4
Let me finish that for you..."Drives like an amazing fat pig." :P


RE: "Can be used up to 60mph"
By EricMartello on 5/21/2009 5:30:05 PM , Rating: 2
LOL at the people who paid $70K for a Toureg. Seriously...recouping that extra $50K in fuel savings yet? Probably not.

The TDI Jetta and Golf were both neat little cars tho, not insanely overpriced and they worked rather well.

I'm not a fan of hybrid technology because it is a complicated way to solve a problem that has a simpler solution available now - a modern diesel engine provides better performance with fuel economy that rivals or surpasses hybrids. Not only that, but when the car is retired you won't have to worry about disposing the batteries, which I'd say are not landfill-friendly.

The concept of a compression-ignited gas engine is cool but...diesel fuel has a higher effective octane rating than gasoline, and therefore can withstand greater compression before igniting. This allows diesel engines to produce that massive, low-speed torque they are known for...not just that but biodiesel can be produced from a wider variety of materials vs ethanol...so it pushing for innovations in diesel tech would probably be the best way to go for companies that want user and eco friendly cars.


RE: "Can be used up to 60mph"
By Keeir on 5/21/2009 7:37:27 PM , Rating: 4
quote:
so it pushing for innovations in diesel tech would probably be the best way to go for companies that want user and anti-GW friendly cars.


Fixed it for you. Diesel cars are great, but produce significantly more particule pollution (cause Cancer, Resporitory Issue, etc) and well as significantly more NOx and other real pollutants that directly harm the enviroment.

New engines are solving the emission issue, but they extra costs involved might be used on a gasoline engine based car in ways that make the total "enviromental" impact the same (I am not sure C02 really should be considered, but hey that the way politics/public opinion is headed)


RE: "Can be used up to 60mph"
By EricMartello on 5/21/2009 10:00:35 PM , Rating: 1
quote:
Fixed it for you. Diesel cars are great, but produce significantly more particule pollution (cause Cancer, Resporitory Issue, etc) and well as significantly more NOx and other real pollutants that directly harm the enviroment.


I'd like to see some evidence that clearly links vehicle emmissions to cancer and respiratory ailments...yes, the gases and particulates emitted in diesel exhaust CAN be harmful and in cities where big buildings hinder airflow near the street level, it is a problem, but overall vehicle emissions as a whole account for a very small percentage of the total "harmful emissions" produced by humans. On top of that, newer diesel engines produce far less harmful pollutants - not that it is an issue for me. I am more concerned with performance and not so much MPG or eco-friendliness.

quote:
New engines are solving the emission issue, but they extra costs involved might be used on a gasoline engine based car in ways that make the total "enviromental" impact the same (I am not sure C02 really should be considered, but hey that the way politics/public opinion is headed)


Keep in mind that electric motors emit ozone gas which is pretty nasty stuff...and like I said, the batteries used in hybrids will cumulatively be more harmful to the environment when the cars are retired unless they are recycled - but if they are recycled then the energy that the hybrid saves is further reduced, because recycling is a very inefficient process most of the time.

CO2 should not be anyone's concern...it is common gas that has existed on this planet for aeons and will continue to do so. One big volcano eruption will put out more harmful stuff into the atmosphere than humans have for the past 5-10 years.


RE: "Can be used up to 60mph"
By Alexstarfire on 5/22/2009 12:41:33 AM , Rating: 2
While I can't quite remember the show I saw this on, but there is a city in California where people get sick all the time and it causes tons of problems. All of the pollution is caused by diesel emissions as it's a port city.


RE: "Can be used up to 60mph"
By MrPoletski on 5/28/2009 11:58:53 AM , Rating: 2
Redline on my 1.8HDTi ford focus is also 4500 RPM.

I don't know the reason why diesels redline lower than petrols, but I can make a guess. You want your fuel to ignite when your piston is fully down. This could happen early if your engine block is too hot, or if you stamp your piston too fast.

The fuel in the diesel cylinder will ignite when it reaches a certain pressure, but the pressure distribution will not be even. It will get less and less even the faster your pistons move.

Now this might be a negligable difference or it might be 'the reason' but your fuel could ignite early if, on the compression downstroke of your piston, you move the piston so fast that the ignition pressure is reached at the head of the piston but is not reached at the glow plug. As you go faster and faster this means that the ignition of the fuel gets earlier and earlier up until the point where you are igniting your fuel and it is slowing the piston down because it hasn't finished its downstroke yet and is experiencing force due to igniting fuel now instead of after it has finished its compression stroke.

....and as for that car, what do you need 500lbs of torque for?

Are you towing? thing looks like it weighs a couple of tonnes too. You yanks (collectively, not any individuals here in particular) need to go through a serious attitude adjustment when it comes to vehicles (and I think you might be). Bigger is by no means better. I fear this is the kind of car you'd end up with mums dropping their single child off at school in whilst holding up all the traffic coz of their massive cars and poor parking skills. This phenomenon is why I hate the ford Galaxy with a passion.


RE: "Can be used up to 60mph"
By Jeffk464 on 5/21/2009 10:32:33 PM , Rating: 3
The redline on the one I'm looking at right now is 2300.


RE: "Can be used up to 60mph"
By Lord 666 on 5/22/2009 12:56:59 AM , Rating: 4
What vehicle are you speaking of? Year, type, displacement, transmission... you know the supporting facts.


RE: "Can be used up to 60mph"
By andrejs on 5/22/2009 4:11:07 AM , Rating: 2
quote:
diesel's redline are determined by exhaust gas temperature, and is usually around 3000RPM.
quote:


this is incorect, i own a diesel car, and red line is little over 4600 rpm. about 10 years a go we hade ford ecort diesel and its redline was over 5500 rpm


RE: "Can be used up to 60mph"
By mrp0379 on 5/22/2009 9:10:18 AM , Rating: 2
A lot of the engine (both diesel and IC) red line has to do with mean piston speed, which is a factor of both RPM and piston stroke. The longer the stroke, the more distance traveled, hence a higher mean piston speed. To bring the speed back down, you need to increase the amound of time per revolution. Thats why you see ~2000 RPM redlines on commercial vehicles, versus ~20000 RPM on F1 cars.


RE: "Can be used up to 60mph"
By ChugokuOtaku on 5/21/2009 1:34:51 PM , Rating: 2
Well, your car engine sucks up the most gas during acceleration. Once you reach cruising speeds, the engine is much more efficient.


RE: "Can be used up to 60mph"
By erple2 on 5/22/2009 4:35:05 PM , Rating: 4
quote:
Well, your car engine sucks up the most gas during acceleration. Once you reach cruising speeds, the engine is much more efficient.


Curiously, that's technically incorrect. Your car is most efficient at generating power at it's Horse power peak. That means that the engine is consuming the least fuel per horsepower generated at peak horsepower. At lower RPM's, the engine happens to also consume less fuel, but it's also generating less horsepower.

Now, if you look at the total fuel consumed, it is generally less at lower RPM, simply because the engine produces significantly less horsepower as well.

The most efficient highway cruiser would be an engine that at peak generates exactly the horsepower required to maintain speed at it's peak horsepower rating. Picture a tiny Briggs and Straton engine churning out about 15 hp in your reasonably aerodynamic ( about 0.30 Cd ) car. You're not going to get any kind of reasonable acceleration out of it, though.


RE: "Can be used up to 60mph"
By LCC2286 on 5/21/2009 1:35:31 PM , Rating: 2
Maybe it correlates to the 0-3000 RPM range? Develop a new transmission and the problem should be resolved.


RE: "Can be used up to 60mph"
By ChugokuOtaku on 5/21/2009 1:45:28 PM , Rating: 2
I really hope this technology won't only be available with a slushbox/CVT


RE: "Can be used up to 60mph"
By FITCamaro on 5/21/2009 1:52:39 PM , Rating: 4
Well if you were limited to 3000 rpm, you'd need a lot of gears to have it be usable. But as others said, you'll still have traditional spark ignition for higher speeds.

But I agree. I want a manual.


RE: "Can be used up to 60mph"
By Alexstarfire on 5/21/09, Rating: -1
RE: "Can be used up to 60mph"
By FITCamaro on 5/21/2009 2:01:31 PM , Rating: 3
manuals get better fuel economy than automatics due to less drivetrain loss and less weight. CVTs don't have as much drivetrain loss as automatics but still weigh more than manuals. And are far more complicated. Manuals are the cheapest, simplest transmissions.


RE: "Can be used up to 60mph"
By Amiga500 on 5/21/2009 2:31:42 PM , Rating: 2
I agree that used to be the case.

Newer automatics are much closer in fuel efficiency.

Some even have lock-up clutches when not changing gear.


RE: "Can be used up to 60mph"
By Durrr on 5/21/2009 9:38:32 PM , Rating: 4
you mean lock up torque converters as that is the only part of the system that allows "slippage". Those have been around for 20 years.

Here's the order of drivetrain losses from most to least efficient. FWD-Manual (12% loss), RWD-Manual (15% loss), FWD-Auto (19% loss), RWD-Auto (22% loss), AWD manual (25% loss), AWD Automatic (30% loss). Those are round percentages as to how much engine power is lost simply in transmitting power to the wheels because of rotational inertia, mass and transmission losses due to changes in geometry. CVTs are about 2% more efficient than regular autos across the board. If you're really that lazy and don't want a manual, the SMG gearboxes are hydraulically actuated manuals and have the greatest combination of efficiency with user friendliness.

The major loss with automatics are the losses because of the torque converter. Basically, its two fans that transmit energy to each other based on the movement of an extremely viscous fluid.


RE: "Can be used up to 60mph"
By Alexstarfire on 5/22/2009 1:18:51 AM , Rating: 2
I can't say much for all CVTs but for the Prius the drivetrain loss is apparently < 13% on average, according to http://www.toyotanation.com/forum/showthread.php?t... anyway. Who are fucking retarded about driving apparently, but whatever. That's assuming the information is correct. Seems to be on even footing with FWD manuals, at least according to your information. Which BTW I'd like to see a source for.

Now other than that, drivetrain loss doesn't equate to FE. The whole purpose of a CVT is so that you can be in the most efficient gear at all time. Again, can't say much about other CVTs but the Prius does it's job VERY well.


RE: "Can be used up to 60mph"
By afkrotch on 5/21/2009 2:38:42 PM , Rating: 2
Subaru make a manual cvt. Course it's really nothing more than a CVT that mimicks the gears of a manual.


RE: "Can be used up to 60mph"
By Lord 666 on 5/21/2009 3:08:06 PM , Rating: 3
With the lower redline of diesels, users stuck in traffic will be shifting like a crack monkey.

Almost got my TDI in manual, but everytime I drive into NYC, count my blessings I did not. For the 2006 TDIs, the mileage difference was actually one mpg higher for hwy than manual (42 versus 41). It was also an easy way of finding DSGs versus manuals on the dealership lot.


RE: "Can be used up to 60mph"
By Motoman on 5/21/2009 5:46:21 PM , Rating: 3
...not sure of that.

Granted we may not be talking diesels of the same scale, but my 2004 RAM 3500 with the 5.9l HO Cummins Turbo diesel has little problem starting from a dead stop in 3rd (and 1st is all but superfluous)...can be lazy and quasi-coast around a 90-degree corner in 4th and it won't complain much.

In general, I would say that I find myself shifting less with my 5.9l diesel than I did either with the 360c.i. V8 gas motor, or the 8.0l V10 I had in my 2 previous trucks.


RE: "Can be used up to 60mph"
By Lord 666 on 5/22/2009 2:18:18 PM , Rating: 2
After driving the TDI today, watched the shift patterns of the DSG. That's VW speak for a dual clutch transmission that shifts itself and does it much faster than any human could. Much more seamless than CVTs that feel like they are slipping to me. The worst CVT I ever drove was in a Mini Cooper.

Anyway, at 20mph, the car is already in 3rd. 30mph is 4th, about 35 is 5th and around 42 it puts it into 6th. This is regular driving in regular mode, not accelerating. It shifts around 2200rpm and after shifting its 1400-1500rpm. If I drive to the ferry for work, usually get about 50mpg for the 15 minute trip that has 3 lights.

There is a sport mode, but makes the car drive terrible shifting at 3000+rpm and doesn't get much more performance from 100hp/177lbs.


RE: "Can be used up to 60mph"
By Hare on 5/21/2009 3:08:42 PM , Rating: 3
quote:
manuals get better fuel economy than automatics due to less drivetrain loss and less weight. CVTs don't have as much drivetrain loss as automatics but still weigh more than manuals. And are far more complicated. Manuals are the cheapest, simplest transmissions.


I have a European CVT diesel car and it has better MPG figures compared to manual transmission. It's not rocket science. The engine is constantly on the "best" RPM maximizing torque and thus saving fuel. Sure the transmission weighs more but there are still more positive attributes than negatives (price, complexity, weight). The performance figures are quite close if not just a bit better for CVT.


RE: "Can be used up to 60mph"
By Durrr on 5/21/2009 9:41:35 PM , Rating: 2
The transmission itself isn't more efficient. The transmission causes the engine to operate at its torque peak and therefore, makes the engine more efficient.


RE: "Can be used up to 60mph"
By rudolphna on 5/21/2009 3:14:32 PM , Rating: 2
FIT, your information is outdated. Many, if not most, of modern cars actually get better fuel economy from the Automatic version than the Manual.


RE: "Can be used up to 60mph"
By Spuke on 5/21/2009 4:26:55 PM , Rating: 3
It's not that outdated as most autos do NOT get better fuel economy than manuals. SOME of the newer autos are getting the same or better but this a current improvement not status quo.


RE: "Can be used up to 60mph"
By mindless1 on 5/21/2009 4:49:54 PM , Rating: 1
Most of the newer autos get better mileage for one simple reason, the can knows when to shift gears for optimal efficiency better than the average driver does.


RE: "Can be used up to 60mph"
By MrBungle123 on 5/21/2009 4:34:35 PM , Rating: 3
Personally I don't care if it gets worse mileage... I'd rather drive a stick because automatics are boring.


RE: "Can be used up to 60mph"
By mindless1 on 5/21/09, Rating: -1
RE: "Can be used up to 60mph"
By mindless1 on 5/21/09, Rating: 0
RE: "Can be used up to 60mph"
By Hoser McMoose on 5/21/2009 5:17:08 PM , Rating: 5
Personally I find that I am MORE attentive to driving when I'm in a manual transmission vehicle. With a manual you have a much stronger connection to what is going on around you, you get a better feel for speeds and what the car is doing. You aren't be distracted but rather you are concentrated on a driving-related task that keeps your mind focused on other driving tasks like watching where you are going!

With an automatic I find it's far easier to be distracted by non-driving tasks.


RE: "Can be used up to 60mph"
By piroroadkill on 5/21/2009 6:19:23 PM , Rating: 2
I completely agree.

I get pretty good motor memory for routes I drive often and when to shift, and you're definitely more aware of speed all the time. Also, it's fun


RE: "Can be used up to 60mph"
By rudolphna on 5/21/2009 11:31:13 PM , Rating: 3
How do you like shifting in rush hour traffic, stop and go, driving in cities.. I would imagine it would get old after quite some time. I like Automatics. You can relax a bit more than with a manual. Alot of people drive to relax, and worrying about shifting ruins it completely. Should everyone know how to drive a stick? sure. But only in case they ever need to drive one. Automatics shift far smoother than any person I have ever driven with who has a manual.


RE: "Can be used up to 60mph"
By ExarKun333 on 5/22/2009 10:49:20 AM , Rating: 1
No, the rush hour traffic gets old. Automatics are for lazy people. Manual FTW.


RE: "Can be used up to 60mph"
By Spuke on 5/22/2009 12:03:18 PM , Rating: 2
quote:
How do you like shifting in rush hour traffic, stop and go, driving in cities.
I've driven semi-truck manuals in LA stop and go. Cars are nothing. After your calf gets used to the workout, it's really not a big deal. Besides, with damn near everyone driving autos, you never get out of first gear.


RE: "Can be used up to 60mph"
By mindless1 on 5/22/2009 3:40:29 AM , Rating: 1
BS

Your idea of "connection" is nonsense, the fact is, the more attention you have to pay to the act of shifting a car, the LESS attention you have for other things.

Even if you are a great driver, you are not "magic", any attention at all you put into the car RPM and shifting is attention diverted from the road.

That makes for a less responsible driver, and one with excuses.

Being distracted by other non-driving tasks is a 3rd issue, it is even worst when one is stick shifting and has these distractions, but not acceptable either way.

You are not supposed to be focused on "driving", you are supposed to be focused on OTHERS ON THE ROAD.

You utterly fail, are a hazard based on your lacking idea of responsible driving, and thus one of the last people who should be allowed to drive a manual transmission.


RE: "Can be used up to 60mph"
By Spuke on 5/22/2009 12:15:32 PM , Rating: 2
There's really not much attention given to shifting but, to be honest, newbies are going to give more attention to shifting than a person that's been doing it for 20 years. BUT newbies are going to be giving more attention to driving anyways so that's a moot point.


RE: "Can be used up to 60mph"
By mindless1 on 5/26/2009 12:34:54 AM , Rating: 1
There's not much attention needed for lots of things people do in a car but nevertheless it is attention taken away from thinking ahead while driving.

I can't agree that newbies are going to be giving more attention necessarily, stats tend to show the youngest drivers have the most accidents. We could argue about why that is, but I don't think anyone with attention to the fact that they were about to wreck would normally go ahead and chose to do so.


RE: "Can be used up to 60mph"
By GWD5318 on 5/22/2009 3:04:23 PM , Rating: 3
quote:
Your idea of "connection" is nonsense...


Spoken like a person who has never the experience of a perfectly timed down-shift in a tight apex corner. There's more to shifting than just getting the best fuel economy. You will never understand the joy of truly being in total control of your vehicle.

If you're content to let computers to dictate your driving habit, that's cool, but don't begrudge the rest of us who actually enjoy the act of driving.


RE: "Can be used up to 60mph"
By mindless1 on 5/23/09, Rating: 0
RE: "Can be used up to 60mph"
By AlexandertheBlue on 5/24/2009 1:12:38 PM , Rating: 2
quote:
Clue: Only an idiot goes into a turn fast enough they try to make a transmission gear slow the engine, instead of braking to the right speed. I don't misunderstand, rather I am not an idiot like you who risks themselves and others.

Regrettably, you just showed you have no clue what the OP is talking about, because he was not talking about slowing the vehicle. He was talking about properly executing a downshift so that the vehicle could accelerate out of the corner as quickly as possible and not upset the balance of the vehicle by bringing the engine up to speed by re-engaging the clutch.

Shifting a manual takes no more concentration than checking your instruments once you have mastered the skill of shifting. Checking your instruments is something that should be a part of your normal driving scanning routine. Therefore driving a manual doesn't remove your attention from the road as you seem to believe.

Remember you can be alert to what is going on around you and still be looking in the wrong direction. For example, you are quickly scanning the pedestrians on the left side of the street and the car at the street corner on the right decides to make a left turn when you do not have sufficient room to stop. This is why the average time to apply the brake in an emergency situation is approximately 3/4 of a second. It doesn't take that long to physically apply the brakes, the first 1/2 second or more is to recognize the need to stop.

In the future you may find that moderating your tone allows you to get your point across more effectively. Your posts regarding paying attention while driving are well intentioned if incorrect in the details regarding driving a manual transmission. Hence moderating your tone may allow you contribute to the discussion without coming across like a troll.


RE: "Can be used up to 60mph"
By mindless1 on 5/26/2009 12:29:18 AM , Rating: 2
Nobody needs to accelerate out of a turn as quickly as possible.

Remember that alertness is about minimizing distractions, not arguing in favor of them by trying to say oh maybe some other distraction could be a problem too.

It's not trolling to be a mature driver and point out where people have gone wrong. I do honestly think that only idiots care about "performance" driving on public roads, it is a foolish concept held by the minority of drivers who cause more accidents than average.


RE: "Can be used up to 60mph"
By grant2 on 5/26/2009 2:48:12 PM , Rating: 2
Anyone who treats public roads like a racecourse is a menace.

Take it to the track, andretti!


RE: "Can be used up to 60mph"
By FITCamaro on 5/21/2009 7:56:52 PM , Rating: 1
A liberal advocating laziness? Say it ain't so.


RE: "Can be used up to 60mph"
By mindless1 on 5/22/2009 3:35:41 AM , Rating: 2
It would be stupid to do what we already designed a machine to do (take us somewhere).


RE: "Can be used up to 60mph"
By FITCamaro on 5/22/2009 5:52:07 AM , Rating: 3
You're just working towards that future of the movie WALL-E huh? Where mankind is a bunch of fat slobs who can't even barely walk because they rely on machines for everything.


RE: "Can be used up to 60mph"
By mindless1 on 5/23/2009 3:14:25 AM , Rating: 2
On one hand I agree it's nice and maybe important to have control of such things.

On the other hand, there is a limit. I feel no loss by not being able to decide when a gear shifts, it's not like losing control of when I sleep, eat, or shower.

Point is, we don't really need an illusion. Don't need fake BS. Those who manually shift pretend they are significantly "higher performance" or whatever BS is popular on a given day.

Fact is, there is only a small performance difference, and when it exists, in that environment it is offset by an economy loss, and it is offset by the fact that driving on any normal road, it would be ILLEGAL.

Idiots think a manual transmission matters for anything other than hauling heavy loads on a truck. The simpleton idea that it's "more in control" is only a silly vanity that a lone moron needs to be more in control than decades of research shows was the optimal gear shifting RPM vs acceleration rate.

Sad but true, decades ago computers far exceeded any humans' ability to react to a small number of variables.


RE: "Can be used up to 60mph"
By goku on 5/21/2009 4:41:03 PM , Rating: 4
The only reason for THAT is because they're giving the automatics taller gear ratios and the manuals shorter gear ratios as they assume that a person buying a manual is doing it for the "performance" and not for the economy like manuals were traditionally associated with. Until I see an automatic and manual trims of a car with the EXACT same gear ratios and the automatic getting better mileage, I'm still convinced that a manual is more efficient, period.

Playing around with transmission gear ratios is a great way to fool people into thinking one has made a car more "powerful" or more "economical" through "advanced techniques", just look at the Cobalt XFE or the DX/LX Honda Civics vs the EX Civics.


RE: "Can be used up to 60mph"
By mindless1 on 5/21/09, Rating: 0
RE: "Can be used up to 60mph"
By Keeir on 5/21/2009 5:36:58 PM , Rating: 4
quote:
You've contradicted yourself. On the one hand you say manual is more efficient then on the other you say it isn't because of the gear ratios used, so what it "could" be isn't what it actually is.


No... he is fairly clear

A manual gearbox combined with a properly trained driver is more efficient than a Automatic gearbox, even CVT.

However, on the EPA testing, a car company can fudge thier gearing ratios to make the Automatic Car seem just as fuel efficient as the manual

For Example

http://www.vw.com/jettasportwagen/completespecs/en...

Numbers in Parathesis are the Gearing Ratio for Automatic I believe. Lower numbers indicate lower RPM loads on engine. Given the wide range of varietions it appears clear to me that VW is boosting city MPG for manual (to account for poor shifting) but pushing automatic Highway MPG (to account for difference in wieght).


RE: "Can be used up to 60mph"
By goku on 5/21/2009 5:42:51 PM , Rating: 2
I'm not contradicting myself, I'm just saying a car will get less mileage on a Manual today vs. an automatic not because of some magical advancement in the efficiency of automatics but because they (in this case) handicapped the manual artificially. In an apples to apples comparison where the automatic and manual have the same gear ratios, the manual will always win.

I'm surprised that you think the automatic is better because it shifts more optimially but I've found it doesn't shift optimially even with careful manipulation of the accelerator. Sometimes it simply won't shift due mph shiftpoints that are pre-programmed even though the load would indicate that it could infact shift. Sometimes I want to shift into 5th gear from a standstill because I know I'm heading down an incline, and most automatics including geartronic won't do that for me. A manual transmission is just so much more simple and robust compared to an automatic that it isn't any surprise that it's more efficient.

An manual transmission in its self contained entirety is more efficient than an automatic, for the amount of work you have to put in, you'll get more out of a manual.. But that doesn't mean that in a car you'll always get better mileage with a manual because of artificial handicaps like having shorter gear ratios.


RE: "Can be used up to 60mph"
By mindless1 on 5/22/09, Rating: -1
RE: "Can be used up to 60mph"
By Spuke on 5/22/2009 12:18:03 PM , Rating: 3
quote:
It was entirely correct, but idiots don't like truth.
Actually you were not correct as gearing plays the major role in transmissions not some magical (your word) technology in automatics. Goku is correct.


RE: "Can be used up to 60mph"
By mindless1 on 5/23/2009 3:05:59 AM , Rating: 2
Your post is nonsensical. Yes gearing plays a role but your simpleton idea is nonsense.

Automatics are geared for higher fuel economy. Manuals are geared for user response, to provide a false feeling of performance.

Even with a great driver, and an optimum gearing for economy, the manually shifting driver will not do as well as a computer can.

Sorry if you don't get facts, but that's the way it is.

Trying to argue gearing is just stupidity, with any and all gear ratios, the computer will still shift more efficiently than a driver will, because that is how the manufacturer set the control in order to meet fuel efficiency ratings.

Some of you really need a clue, or a lesson about common sense, or something other than how to stick you head up arse.

These are obvious facts. Those arguing against them are either ignorant enough they had no business commenting on a topic they were so ignorant about, or had an agenda and did not care about truth at all.


RE: "Can be used up to 60mph"
By AlexandertheBlue on 5/24/2009 1:32:56 PM , Rating: 2
There is one thing a human brain can do that a computer can not. That is anticipate. Computers are limited by their programming. The programming is restricted to variables that the computer is given sensors to detect. For example, a vehicle on cruise control will tend to accelerate as it crests a hill due to the reduction in engine load. A human modulating the throttle will not do so if they are paying attention.

It is rare that an automatic will beat the EPA fuel economy estimates. It is much easier to do in a manual because you can reprogram your shift points on the fly far more flexibly than an automatic will ever be programmed to do. You can choose to accelerate very slowly by shifting very early. An automatic will never be programmed to shift so early because of the perceptions of the driver of the automatic transmission. It would make the car feel slow in certain situations and the manufacturer will never allow that to happen, as that would make that car seem worse than others on the road. Driving is not as cut and dried as you are making it out to be. And neither is the programming of shift patterns, injection durations and timing and ignition timing just to name a few.


RE: "Can be used up to 60mph"
By mindless1 on 5/26/2009 12:32:33 AM , Rating: 2
Untrue, thanks to the fuel efficiency mandates they are placing automatic shift points where they achieve near maximum efficiency. If they weren't doing that, then I would agree a manual transmission does have the potential to be more efficient, but they are.


RE: "Can be used up to 60mph"
By Spuke on 5/26/2009 12:44:58 PM , Rating: 2
quote:
Untrue, thanks to the fuel efficiency mandates they are placing automatic shift points where they achieve near maximum efficiency.
Not in totality. Some automatics might be setup that way but most definitely not all. And those that are will only function in that mode in certain situations.


RE: "Can be used up to 60mph"
By mindless1 on 5/26/2009 8:06:11 PM , Rating: 2
Yes, certain situations like MPG tests or conservative driving.

Those making claims about manual transmissions are still using contradictory arguments. On the one hand they want to claim it's a virtue speeding up faster coming out of a curve, and on the other hand they want to ignore the fact that this driving style is what causes lower efficiency.

They want to feel in control and push their car then ignore that they are deliberately chosing to drive less conservatively which goes back to the central issue, that people choose manual transmissions in passenger vehicles only because they are cheaper in economy cars, or to drive the car in a less efficient manner.

There is no other reasonable preference for a manual transmission today or for the many years since autos became reliable and long lasting.

It's silly really, it would be like the owner of an oven claiming they can get more performance by manually turning the heating element off at temp, on again when it drops below temp, several dozen times to merely bake something.

In an automobile, it could be equated to manually having to turn your blinker on and off dozens of times at every turn. Someone might claim manual control will give a blink pattern they argue uses less power or draws more attention or any other silly thing, when the point is not to be a slave to needless things.

Lastly, yes most are definitely set up for fuel economy, as much as the other factors like weight, aerodynamics, engine specs allow. There is still a driveability factor, but even then the smooth shifting of an auto is inherantly more efficient than manually doing so in normal, sane driving.

What class of cars are by far the most popular? Midsized sedans. Take a look at this fuel economy list:
http://www.mpgomatic.com/2007_family_sedans.html

The top 4 are automatics, and 7 out of the top 10 are automatics. For most people a manual transmission is not chosen for fuel economy, it's like a passing excuse for their desire to pretend they are in more control for an important reason.


RE: "Can be used up to 60mph"
By sprockkets on 5/21/2009 5:41:59 PM , Rating: 4
The EPA says that an 5 speed auto Mazda6 2.5L will get 2 MPG than the 6 speed manual.

In REAL LIFE TESTING, Car and Driver got 3MPG better on the manual.

Don't trust what the ratings say. While it is true an auto can upshift much sooner than any person could in a manual, you still always lose 10-15% of useable energy in the torque converter, and while it can lock up to overcome this loss, it can't do it 100% of the time.


RE: "Can be used up to 60mph"
By Spuke on 5/22/2009 12:21:38 PM , Rating: 2
quote:
While it is true an auto can upshift much sooner than any person could in a manual
Not always true. A professional driver can and has shifted faster and smoother than most autos. The only tranny's that are faster are some of the newer, high performance dual clutch units.


RE: "Can be used up to 60mph"
By andrinoaa on 5/21/09, Rating: 0
RE: "Can be used up to 60mph"
By Spuke on 5/21/2009 4:28:04 PM , Rating: 4
quote:
There you go again, just chanting mantras. Don't you have a life?
Disprove what he said with actual data then you might be on to something.


RE: "Can be used up to 60mph"
By Pneumothorax on 5/22/2009 1:13:15 AM , Rating: 2
Give it up Camaro, almost all the posters here have no love for cars. Most here would not appreciate manually rowing your own gears, getting the perfect heel-toe around a corner...


RE: "Can be used up to 60mph"
By Spuke on 5/22/2009 12:26:19 PM , Rating: 2
quote:
almost all the posters here have no love for cars.
So he should shut up because some people aren't into cars? If you can say what you want, he can say what he wants.


RE: "Can be used up to 60mph"
By Veerappan on 5/28/2009 2:45:04 PM , Rating: 2
I read that as more of exasperated support than as a recommendation to stop. It seems that some people here are either against manual transmissions in general (mindless1... very appropriately named), or want only diesel-hybrid CVT-based cars.

Important notes for some people to get into their heads:
- A manual gives you more control over the shifting patterns of the car
- A manual will incur less loss of power/efficiency because of the weight/complexity and other factors already noted
- You don't have to make a choice to only drive aggressively, or only conservatively. Some people know how to do either depending on the location/situation.
- Engines do have an RPM range where they are most efficient, and if the driver of a manual knows those ranges, they can get as good as or better mileage than an automatic transmission.
- Driving a manual allows you to anticipate changing road conditions/elevation changes, which may provide an advantage over an automatic with regards to efficiency.
- Some people WANT to be able to control which gear their car is in. The desire for this control does not make them idiots.
- Most people are too lazy or apathetic to want to drive a manual.


RE: "Can be used up to 60mph"
By Spuke on 5/28/2009 7:23:06 PM , Rating: 2
quote:
I read that as more of exasperated support than as a recommendation to stop.
I went back and reread it after your post and that indeed sounds like what he was saying. My mistake.


RE: "Can be used up to 60mph"
By Jeffk464 on 5/21/2009 10:36:16 PM , Rating: 2
I worked on nissans for a year and so drove a lot of the cvt's. They had no quirks at all that I could tell and seemed just as reliable. I personally liked the smooth ride they provided for sedans, maybe not ideal for a sports car. With the boost in mileage and good reliability I don't see why not go cvt.


RE: "Can be used up to 60mph"
By puffpio on 5/21/2009 1:35:57 PM , Rating: 4
HCCI and Diesel engines have problems at higher RPM's because at those engine speeds, you can't precisely control when the compression will ignite the mixture...good diesels can now rev to 5000-6000 rpm or so.

For today's HCCI technology..they will run to like 3000 RPM in HCCI mode, and then switch to regular spark ignition at higher RPM. you can see in the 2nd pic there is still a spark plug in the HCCI motor.

Who knows, in the future maybe they can control HCCI at high rpm too..


RE: "Can be used up to 60mph"
By Motoman on 5/21/2009 2:40:03 PM , Rating: 2
...I vaguely remember Honda testing some oddball quasi-diesel thing in a desert racing bike a while ago. Can't remember the name for it...but it was basically a 2-stroke motor that would "diesel" up to some rev limit, then switch to regular spark-induced 2-stroke glee above that. ?


RE: "Can be used up to 60mph"
By Hare on 5/21/2009 2:44:13 PM , Rating: 1
I don't understand why the rpm would be a problem unless the engine doesn't produce enough torque for high speed. The RPM figure doesn't really say anything since speed is just a matter of transmission ratio.

For comparison: I have a diesel car and I barely hit 2000rpm when going 60mph (around 310nm torque @ 2000rpm).


RE: "Can be used up to 60mph"
By rudolphna on 5/21/2009 3:19:07 PM , Rating: 2
Diesels, and this new HCCI engine, are high compression engines. For one thing, to withstand the much higher compression, the piston, conn rod, crankshaft and associated bearings must be made much stronger (and thus heavier) to withstand the higher pressures and stresses, over a gasoline engine. In addition, the higher the RPM of a diesel, the higher the EGT, as diesel engine speed is dictated by amount of fuel injected into the cylinder at peak compression. More fuel burned= more heat. All these factors contribute to a much lower redline than even similarly sized gasoline engines.
However, in the case of this HCCI engine, since the fuel is premixed, and I would assume engine speed is dictated by an air throttle, as with normal gas engines, that the only real limit is the amount of rotating mass, and design limits. Of course, I suppose EGTs could factor into this, but it doesn't seem like as big of an issue as with a bog standard diesel.


RE: "Can be used up to 60mph"
By mindless1 on 5/21/2009 5:05:42 PM , Rating: 2
1) Rate of burn when using compression based ignition.

2) Increased # of ignitions from higher RPM per unit time builds up more heat, when the point was keeping NOx low.

There may also be issues of how quickly the engine can adjust to keep the required temperature zone, fuel delivery, etc. Mechanical parts are bound to lower operational speed than something like a computer. There may also be limitations in fuel subsystem pressure as it effects longevity of the design or dozens of other parameters we don't know because we haven't developed the tech ourselves and they're not about to give away the farm on every technical aspect of a product they developed for profit.


RE: "Can be used up to 60mph"
By diggernash on 5/21/2009 7:18:50 PM , Rating: 2
How long has Yamaha been using direct injection in their marine outboards?


Ummm...
By Motoman on 5/21/2009 1:35:58 PM , Rating: 2
quote:
Traditional gas engines inject fuel into a prechamber where the burn starts, whereas diesel engines put it directly into the combustion chamber, a more efficient process.


..."prechamber?" I'm thinking that injection goes into the intake tract, and when the intake valves open the charge is sucked into the cylider, and after the compression stroke when all valves are closed the the burn occurs. I am rather sure that if you "started the burn" inside the intake tract somewhere, and/or at some point when the valves were open, you'd have a really big mess on your hands.




RE: Ummm...
By SublimeSimplicity on 5/21/2009 1:43:04 PM , Rating: 3
A prechamber is how diesel engines worked before the advent of direct injection and turbochargers. The author is a little confused.


RE: Ummm...
By Amiga500 on 5/21/2009 2:22:57 PM , Rating: 1
You don't need a turbo to have injectors.


RE: Ummm...
By bhieb on 5/21/2009 1:56:55 PM , Rating: 3
Correct that paragraph needs works. The "burn" is always started in the cylinder in a gas engine. Jason should fix that.


RE: Ummm...
By Alexstarfire on 5/21/2009 2:03:53 PM , Rating: 5
Wait... you mean to say the great Jason Mick got some information wrong? Nooooooo way.


RE: Ummm...
By mindless1 on 5/21/2009 5:09:14 PM , Rating: 3
I like this one:

"... four-cylinder engine unveiled at the company's research and development center this week may be the first engine to bring compression to the world of gas engines."

I'm sure there's a gas engine somewhere that doesn't use compression, but I've not seen one in a car.


RE: Ummm...
By bludragon on 5/21/2009 2:04:52 PM , Rating: 4
Yep, the next paragraph is quite inaccurate too:

quote:
The second diesel advantage is compression ignition. In a diesel engine, the compression heats the air to a sufficient temperature for ignition, and the compression causes the combustion to be evenly distributed. In a traditional gasoline engine, compression is limited by design so less-efficient spark ignition must be used. This problem has yet to be solved in a production model.


The compression actually causes ignition, not the temperature. Also, I believe the main efficiency advantage diesel has is that it doesn't need a throttle. Petrol engines generally can't use compression ignition as the temperature and pressure would be such that the petrol would detonate (explode) rather than burn. Also, diesel has an inherant advantage in that there it stores more energy per gallon than petrol.


RE: Ummm...
By Amiga500 on 5/21/2009 2:29:54 PM , Rating: 2
Pressure = density * gas constant * Temperature

Temperature causes the ignition.

What are you on about when you say explode rather than burn? Both explode - explosions are what happen when you rapidly expand any medium (in this case air).

I'm also not sure what your on about with regards the throttle - of course diesels need a throttle - no diesel = no go.


RE: Ummm...
By SublimeSimplicity on 5/21/2009 2:38:28 PM , Rating: 1
Diesel engines don't have a throttle plate, butterfly value, whatever you want to call it.

They are throttled by the amount of fuel injected.


RE: Ummm...
By Amiga500 on 5/21/2009 2:46:03 PM , Rating: 1
Which is the point I made in my last line. :-)

I'm quite well aware of how a diesel is throttled!

I was cursing quite a bit a couple of weeks back when the injector pump on the tractor got clogged with dirt and kept cutting the f**ker out.


RE: Ummm...
By JasonMick (blog) on 5/21/2009 2:52:12 PM , Rating: 1
This gets back to my point about direct injection. The gains you guys are talking about based on throttling basically boil down to control/efficiency gains from direct injection (versus spark ignition and valved throttling).

As I mentioned, GDI (gasoline direct injection) technology is becoming pretty common, and a number of GDI engines do not have/need throttle plates AFAIK -- they are controlled by injection.

Source:
http://www.autofixworld.com/index.php?option=com_c...

I clarified the paragraph on fuel compression v. spark ignition, I appreciate the comments.

Again, pairing a slightly improved version of this with GDI, and possibly a hybrid electric assist and/or turbocharging could lead to an engine with both awesome performance and efficiency not seen outside the diesel world. I'm sure big obstacles remaining to combining these technologies, which just now are seeing individual implementation, but it doesn't seem insurmountable.


RE: Ummm...
By SublimeSimplicity on 5/21/2009 3:06:46 PM , Rating: 3
I'm fairly certain all gasoline engines (DI or not) use some form of air throttling. Some BMW engines don't have throttle plates, because they throttle the air intake by adjusting the length of the intake valve stroke.

Throttling a gasoline engine by adjusting the air/fuel mix would cause it to knock... which brings us back to GMs invention here :)


RE: Ummm...
By JasonMick (blog) on 5/21/2009 3:19:35 PM , Rating: 1
Well, my source I linked there (which seems to give a pretty technical description) states:

quote:
Why is GDI better than port injection?

Unlike port injection where fuel is sprayed behind the intake valve, GDI reduces intake manifold inefficiencies that limit air and fuel mixing, and allow fuel to evaporate outside the cylinder. The lack of a throttle plate in some engines also eliminates pumping losses. The direct injection fuel spray cools the cylinder, allowing higher compression ratios. The cylinder charge is localized and thoroughly mixed, bringing tiny fuel droplets nose to nose with oxygen for faster, more efficient burning.


Note the bolded sentence, that's where I gleaned that from. It could be incorrect, though.

Thinking about it logically, if you're using GDI, your directly putting the fuel in the combustion chamber, so you could only throttle the flow of air into the chamber... which I guess is possible, but it seems like the DI could provide throttling without knock if properly performed.

Again, sorry I can't give a definitive answer, but I don't have an EcoBoost or other GDI engine sitting around that I can disassemble (the only surefire way to verify the throttling scheme). And most of my Ford/GM contacts are PR people, so I doubt I'd receive a conclusive answer there.

But for the benefit of all of us, if anyone can chime in with a definitive (and correct) answer I'd be happy to address the wording/make any tweaks necessary.


RE: Ummm...
By Spuke on 5/21/2009 3:23:51 PM , Rating: 2
You don't need to disassemble the engine, just look for a throttle plate. A quick look under the hood will suffice.


RE: Ummm...
By mindless1 on 5/21/2009 5:12:10 PM , Rating: 2
On many modern cars, you are likely to have to start disassembling the engine, at least the air intake or plastic covers, to get at the throttle plate to see it.


RE: Ummm...
By JasonMick (blog) on 5/21/2009 3:24:04 PM , Rating: 1
Ah just noticed you mentioned air throttling as well. Not sure how you would throttle it without a valve/plate, though... I thought that was the definition of throttling (i.e. blocking flow via mechanical closure)...


RE: Ummm...
By Spuke on 5/21/2009 4:30:21 PM , Rating: 2
quote:
Not sure how you would throttle it without a valve/plate, though
That's what he means by air throttling.


RE: Ummm...
By SublimeSimplicity on 5/21/2009 4:54:31 PM , Rating: 2
Your source quote says, "The lack of a throttle plate in some engines also eliminates pumping losses". Like I've said BMW doesn't use a throttle plate, but still throttles the air flow (which still introducing pumping loss, but BMW says less so than a plate).

Diesels control engine power by manipulating the amount of fuel injected into the cylinder, which alters the air/fuel ratio. They also manipulate the boost level in a turbo diesel, but that's another story.

Point is GDI engines don't do that (minus this GM one and maybe not even it). They must limit the air coming into the engine some how to control the engine power.


RE: Ummm...
By Spuke on 5/22/2009 12:28:09 PM , Rating: 2
quote:
Like I've said BMW doesn't use a throttle plate, but still throttles the air flow (which still introducing pumping loss, but BMW says less so than a plate).
The 335i has a throttle plate as do most, if not all, the current GDI engines on the market.


RE: Ummm...
By Spuke on 5/21/2009 3:22:17 PM , Rating: 2
Every GDI car that I'm aware of still has a throttle plate. They are not controlled by the fuel injection. The fuel pressure does vary but it does so on a regular fuel injected engine also.


RE: Ummm...
By mindless1 on 5/21/2009 5:13:47 PM , Rating: 2
Fuel pressure doesn't always vary on a regular fuel injected engine, some have constant pressure fuel rails with injector timing alone determining fuel rate.


RE: Ummm...
By Spuke on 5/22/2009 12:29:32 PM , Rating: 2
quote:
Fuel pressure doesn't always vary on a regular fuel injected engine
I didn't say it always did, just said it does but some people may need the clarification. Thanks.


RE: Ummm...
By geddarkstorm on 5/21/2009 3:12:04 PM , Rating: 2
I'm not an expert in any way on vehicle engines, and could be rather misinformed so correct me if I'm wrong, but I don't think the reasons you gave are why gasoline engines don't usually use compression. As pointed out above, it's always an explosion (rapid expansion) that happens in the cylinder, and the kinetic force from which is what drives the power train.

I'm sure you've heard of "knocking", when a gasoline engine ignites the gas via compression/temperature ahead of a spark (called pre-ignition), throwing the whole system out of whack. It doesn't usually instantly destroy an engine, but it will eventually, as you lose your timings and will crack your cylinders. One of the main reasons for adding octane to gasoline is to make it harder to ignite the gas via compression/temperature, thus preventing "knocking" by ensuring even, properly timed burning. So, that's really the reason compression isn't used -- it's very hard to keep it timed right, and keep the strokes of the cylinders even. Diesel engines still have this issue at high RPMs, which keeps their RPMs lower than most gasoline engines.


RE: Ummm...
By menace on 5/21/2009 7:06:10 PM , Rating: 2
HCCI essentially runs on "knocking" type ignition. The challenge of HCCI is to control the timing of ignition. A computer controls the variable valve actuation giving some degree of stoke-to-stroke control over compression ratio (by varying intake valve) and direct exhuaust gas recirculation (by varying exhaust valve) to make adjustments that keep the fuel detonation occuring at the optimal moment. This should be manageable without damaging the engine if you can maintain adequate timing control but as a previous poster said the increased stress due to higher compression and detonation force likely means you have to beef up the engine a bit to handle it.


turbo deisel hybrid
By DADIO917 on 5/21/2009 1:33:02 PM , Rating: 3
Two comments -
1) given the efficiency of Audi and others turbo deisels i don't see why we don't have turbo deisel hybrids on the way. Seems to me another 20% mpg over prius with existing technologies.

2) the comment about "0 to 60" sound slike it will still need spark ignition. Sounds like more complications. KISS!!!




RE: turbo deisel hybrid
By Spivonious on 5/21/2009 1:41:57 PM , Rating: 2
I think diesel hasn't caught on over here because diesel fuel has higher taxes and therefore costs more than gas. Any fuel efficiency gains are lost in the higher price per gallon.


RE: turbo deisel hybrid
By FITCamaro on 5/21/09, Rating: 0
RE: turbo deisel hybrid
By Spuke on 5/21/2009 4:31:52 PM , Rating: 1
quote:
Right now diesel is cheaper than premium here.
Don't know why you got rated down here. The price of diesel in the US varies wildly. Where I live it's a little cheaper than 87 octane.


RE: turbo deisel hybrid
By bruce24 on 5/21/2009 10:01:33 PM , Rating: 2
quote:
Don't know why you got rated down here. The price of diesel in the US varies wildly. Where I live it's a little cheaper than 87 octane.


On average in the U.S. Diesel is now less expensive than regular unleaded. A month ago, on average, Diesel was priced higher than Premium.

http://www.fuelgaugereport.com/


RE: turbo deisel hybrid
By Spuke on 5/22/2009 12:33:28 PM , Rating: 2
Not everywhere and that's my point. Rate me down if you want but it's not cheaper everywhere.


RE: turbo deisel hybrid
By bruce24 on 5/22/2009 2:59:55 PM , Rating: 2
quote:
Not everywhere and that's my point. Rate me down if you want but it's not cheaper everywhere.


Not sure what your being so touchy about. The link I provided showed numbers that happen to have agreed with what you posted. It also shows, that yes nationally, which doesn't mean everywhere in the U.S. the price premium for Diesel has greatly dimensioned over the past year.

http://www.fuelgaugereport.com/


RE: turbo deisel hybrid
By Lord 666 on 5/21/2009 3:12:39 PM , Rating: 2
Tax difference is extremely small; the Fed tax is something like .17 for gas and .24 for diesel.

In some gas stations around me, diesel is cheaper than gas again. Hasn't been that way since 2006.

Personally, I am hoping there is a real gas tax that makes petrol $4.00 a gallon and diesel stays where it is now.


RE: turbo deisel hybrid
By FITCamaro on 5/21/09, Rating: 0
RE: turbo deisel hybrid
By Lord 666 on 5/21/2009 4:33:41 PM , Rating: 1
Sure there is a good reason; Obama is in office. How do you think all of these project will get true funding?

Whats next is Obama's plan to provide stimulus money as incentives to remove old cars off the road to meet his 2016 deadline. Hasn't been decided if its going to be based on mpg or emmissions, but either way the funding for it isn't going to be sourced by a money tree.


RE: turbo deisel hybrid
By Atheist Icon on 5/22/2009 11:52:25 PM , Rating: 2
Either one of those would screw a majority of the people who voted for him over. Do you really think people living off of Uncle Sam tit have money to buy Fuel Efficient vehicles? Hell, by the standards that he has set for the Automakers, none of my 4 cars even meet that. There will be rioting in the streets....at least by me.


RE: turbo deisel hybrid
By Lord 666 on 5/23/2009 12:26:38 PM , Rating: 2
Traditionally, the EPA hasn't forced old cars off the road as long as they meet emmission specs for their date of manufacture. However, not sure if its going to stay that way.

The law that was passed in 2005 for diesels has a very long grace period; all diesels must be ULSV compliant by 2030. This accounts for tractors and other off road use along with commercial. My 06 TDI legally can do 500ppm sulfur versus 07 and later requiring 15ppm along with other emmission requirements. Should give a longer useful life out of my car and a lot less complex emmission-wise. That's why I am looking for an 06 TDI Toureg as well


RE: turbo deisel hybrid
By Hoser McMoose on 5/21/2009 3:14:56 PM , Rating: 1
It's more a question that diesel is taxed LESS than gasoline in Europe rather than that it is taxed MORE than gasoline here.

By anything remotely resembling 'intelligent' taxation on fuels diesel should be taxed more. Whether a fuel tax is based on energy content or on some guesstimate of environmental impact (eg. CO2 emissions) diesel should be taxed probably 15% higher than gasoline.

In the U.S. this is fairly close to how much more it is taxed, though individual states do vary. In Europe, on the other hand, diesel is illogically taxed LESS than gasoline, often a LOT less!

The reason why Europe taxes diesel less likely is mainly a trade issue, or more specifically a non-tariff trade barrier. European vehicle manufacturers have a long history of making diesel vehicles and are arguably the best in the world at this. By implementing taxation policy that encourages diesel vehicles the European governments are placing their own manufacturers at a bit of an advantage relative to the American and Asian manufacturers who have less experience with diesel vehicles.

The U.S. does much the same thing with their ethanol taxation (subsidy) policies.


RE: turbo deisel hybrid
By FITCamaro on 5/21/2009 3:47:07 PM , Rating: 1
You can keep believing that fuels should be taxed by how much CO2 they put out all you want. It doesn't bring the lie of man-made climate change any closer to reality.

'Intelligent' taxation on fuel should be to tax it just enough to maintain the roadways. No more. No less. And if you have another way to pay for the roads, then it shouldn't be taxed at all.


RE: turbo deisel hybrid
By Keeir on 5/21/2009 7:25:22 PM , Rating: 2
Ummm Fit

I see nowhere in his post that his endorses AGW, GW, or excessive taxation.

Instead he points out that -whatever- the end goal of taxing fuel is, Diesel should be taxed more.

If the goal is to maintain roads, then since a gallon of diesel has a higher amount of energy than gasoline, it will place a relatively higher amount of road load than the gallon of gasoline. Thus, Diesel should be taxed at a slightly higher rate than gasoline.

If your goal is to reduce CO2 (whether this is a good goal or not is besides the point), the most efficient means to do so in classical economics is to directly tax production of C02. A diesel engine produces more C02 per gallon than gasoline.


RE: turbo deisel hybrid
By FITCamaro on 5/21/2009 8:03:30 PM , Rating: 1
quote:
If the goal is to maintain roads, then since a gallon of diesel has a higher amount of energy than gasoline, it will place a relatively higher amount of road load than the gallon of gasoline. Thus, Diesel should be taxed at a slightly higher rate than gasoline.


Correlating the amount of energy a gallon of diesel has vs. that of gasoline to the amount of load on the road for taxation purposes is absurd. You're saying that a tiny diesel car puts more of a load on the road than the same size gasoline car? No.


RE: turbo deisel hybrid
By Keeir on 5/21/2009 8:10:57 PM , Rating: 2
quote:
Correlating the amount of energy a gallon of diesel has vs. that of gasoline to the amount of load on the road for taxation purposes is absurd. You're saying that a tiny diesel car puts more of a load on the road than the same size gasoline car? No.


No.

I am saying that the SAME car with a gasoline engine will consume more gallons of gas to go 15,000 miles than the SAME car with a diesel engine. In theory, this same 15,000 miles puts the same wear and tear on the road regardless of the fuel type.

In practice, the same car with a diesel engine is heavier than the gasoline car (Typ.), making its 15,000 miles a slightly higher load than the gasoline engine. But whatever, its pretty tiny usually.

However, since Diesel and Gasoline are taxed by the gallon, the driver of the gasoline car will pay more taxes than the Diesel car driver. IE pay more for the same "Service" of road repair for the "SAME" car.


RE: turbo deisel hybrid
By Spuke on 5/21/2009 3:45:03 PM , Rating: 2
quote:
I think diesel hasn't caught on over here because diesel fuel has higher taxes and therefore costs more than gas.
It hasn't caught on over here in the States because of the effective ban on them by California, the US largest car market. Only recently have diesels been able to consistently pass emissions and who knows how long that will last. And then there's the stink and noise perception.


RE: turbo deisel hybrid
By FITCamaro on 5/21/2009 3:52:48 PM , Rating: 1
They buy the most cars yet its a state known for hating them. Oh the irony. Love it how its been two days since our latest industry crippling emissions standards were mandated and already California is saying "its not high enough" and looking to come up with even higher standards for after 2020. They won't be satisfied until everyone but politicians and actors are driving insanely tiny electric cars. But Pelosi will have her private military jet to fly between her home and DC at our expense.


RE: turbo deisel hybrid
By Spuke on 5/21/2009 5:07:35 PM , Rating: 2
quote:
They buy the most cars yet its a state known for hating them. Oh the irony.
If it's in a pickup truck, then they love diesels. LOL!


RE: turbo deisel hybrid
By erple2 on 5/22/2009 9:00:31 PM , Rating: 2
quote:
They buy the most cars yet its a state known for hating them. Oh the irony.


You can't really blame California for buying the most cars when they also happen to have the highest population (50% higher than the next highest state, Texas).

quote:
Love it how its been two days since our latest industry crippling emissions standards


I seem to remember the American Car Company Executives being "happy" about it - something about standardization for the whole country...

quote:
But Pelosi will have her private military jet to fly between her home and DC at our expense.


That's not really fair - all politicians are happy to ride around at the tax payer's expense...


RE: turbo deisel hybrid
By FITCamaro on 5/21/2009 1:49:12 PM , Rating: 4
Well the main advantage here is that if they can make a gasoline powered engine with the efficiency of a diesel but at the cost of not much more than a standard gas engine, they win doubly. The downside of diesel is that it is more expensive due to requiring a block and cylinder heads that can handle the compression ratios a diesel commands (like 22:1 or higher vs 8.5-11:1 for gas).

If they can do that, they can build these with turbos on them as well for a cheaper price than turbo diesels and the same mileage. So you'd have a turbo HCCI motor vs. a turbo diesel. However I think diesels will still have more potential for performance enthusiasts due to the heavier duty materials used in the construction of the engine.

Of course these engines might need the heavier duty materials as well. If so then yes, there's not much point to it except that gas is far more widely available than diesel.

Of course as I've said time and again, algae produced diesel. Clean, doesn't use food crops, and can be done here in the US, can use existing infrastructure. Just would require a lot of greenhouses to be built. But we've got a lot of unused land in this country and this would give us far more usable energy for vehicles than solar or wind.


RE: turbo deisel hybrid
By Alexstarfire on 5/21/2009 2:02:11 PM , Rating: 3
Yea, the lower emissions they talk about using HCCI over diesel must be useless.


RE: turbo deisel hybrid
By sprockkets on 5/21/2009 5:45:52 PM , Rating: 2
But diesels also put out less emissions but put out more particulate matter, which can be filtered.

No matter what though, the HCCI engine will probably go back to normal operation once temps get too high.


RE: turbo deisel hybrid
By Alexstarfire on 5/22/2009 12:46:03 AM , Rating: 2
If I recall, reducing the particle emissions on a diesel wasn't exactly cheap.


RE: turbo deisel hybrid
By Spuke on 5/22/2009 12:39:01 PM , Rating: 2
quote:
If I recall, reducing the particle emissions on a diesel wasn't exactly cheap.
It's not and now you have the added expense of refilling your urea tank. I read that it costs the same per gallon as diesel fuel. Anyone know how often you have to fill it and how big the tank is?


RE: turbo deisel hybrid
By AlexandertheBlue on 5/24/2009 1:48:25 PM , Rating: 2
quote:
like 22:1 or higher vs 8.5-11:1 for gas


The difference is bit closer that you were aware of FIT. Gasoline engines with compression ratios in the 13:1 range are available to the public. They definitely require premium though. Turbo diesel's compression ratios start as 'low' as 17:1


By FITCamaro on 5/21/2009 3:39:51 PM , Rating: 2
They're not special. There's plenty of direct injected motors out there now.

As far as 2 plugs per cylinder, Dodge has been doing that since 2003 on the Hemi(at least my parents Durango has 2 plugs per cylinder). Not sure how many other cars do this as well though.


By ChuckDriver on 5/21/2009 6:29:17 PM , Rating: 2
quote:
As far as 2 plugs per cylinder, Dodge has been doing that since 2003 on the Hemi(at least my parents Durango has 2 plugs per cylinder). Not sure how many other cars do this as well though.


Mid-to-late '80s Nissan Stanzas had 2 plugs per cylinder as well. Apparently there is enough of a benefit to justify spending twice as much on cables and plugs for each car.


By FITCamaro on 5/21/2009 7:58:28 PM , Rating: 2
If that was the case I would think more luxury or performance vehicles would do it.


By Spuke on 5/21/2009 4:07:19 PM , Rating: 3
The Civic Hybrid does not use direct injection. It's a standard fuel injected motor. None of the Japanese automakers have DI engines in their US cars. I hear that Nissan is working on one that will go into the Infiniti V6 cars. Cars with DI engines in the US are the Mazdaspeed3/6, BMW 335i, Pontiac Solstice GXP/Saturn Sky Redline, Chevy HHR SS, and the Chevy Cobalt SS.


By Suntan on 5/21/2009 4:11:03 PM , Rating: 2
The 2 liter turbocharged engine found in many VW vehicles is also DI. It was one of the first offered in America with DI.

-Suntan


By FITCamaro on 5/21/2009 4:33:34 PM , Rating: 2
The 3.6L V6 in the Cadillac CTS and new Camaro is direct injected. My friends 2006 Lexus IS350 is direct injected. The 135i is direct injected. The Mini Cooper S is direct injected. The Porsche Carrera is direct injected. Your list is incomplete. I'm sure I'm missing some as well.


By FITCamaro on 5/21/2009 4:34:52 PM , Rating: 2
The IS250 is also direct injected.


By Spuke on 5/21/2009 5:08:51 PM , Rating: 2
Thanks for the corrections. I didn't know the that the IS250 was DI.


By Spuke on 5/21/2009 5:11:45 PM , Rating: 2
I think most of Porsche's engines are now DI'd. Wow, I missed a lot of cars. I should know better about the Mini as my wife is interested in one and I only wanted the turbo DI version. Silly me. Thanks again.


By Atheist Icon on 5/22/2009 11:58:00 PM , Rating: 2
Ford used 2 plug per cylinder back when the 2.3L was prevalent in just about everyone of their vehicles.


Controlled engine knock...
By SublimeSimplicity on 5/21/2009 1:58:09 PM , Rating: 5
This article explains in many words what is basically engine knock. This is a phenomenon that is avoided at all cost in cars, because of its destructive release of power.

Normal combustion happens relatively slowly relative to the motion of the piston. The explosion starts at the spark plug and the flame front moves out towards the cylinder walls. The motion of the piston (lowering pressure by increasing volume) and the rise in pressure from the explosion work at close to even rates to keep the pressure in the cylinder relatively even throughout the power stroke.

Knock, like the article says, causes ignition points all over the chamber at once. This quickly raises the cylinder pressure and burns through all the fuel in the chamber. So instead of spreading out the energy release it happens all at once. This causes the peak pressure to be as much as 10x that of normal combustion.

The benefit is that you've converted all that potential energy in the fuel into pressure and get almost the entire power stroke to turn it into mechanical energy. Where as under normal combustion you're still releasing energy as the piston reaches the end of the power stroke. That heat and pressure gets released out the exhaust port.

I imagine this is why RPMs and power (speed) are limited on this engine, because you need to build an engine block that will put up with being exposed to 10x the stress of a normal engine.




RE: Controlled engine knock...
By FITCamaro on 5/21/2009 2:03:00 PM , Rating: 4
So basically a diesel engine. :)


RE: Controlled engine knock...
By SublimeSimplicity on 5/21/2009 2:12:12 PM , Rating: 4
But diesels are different because the fuel is different. Diesel fuel takes more of a catalyst (heat or pressure) to start combustion. This means that the flame front will spread slower naturally. Plus diesels are usually turbo charged, pressure also slows the flame front.


RE: Controlled engine knock...
By FITCamaro on 5/21/2009 2:46:11 PM , Rating: 4
I was speaking more of your comment on how they have to build a motor that can handle far higher pressures and temperatures than a standard gas engine.


RE: Controlled engine knock...
By mindless1 on 5/21/2009 5:21:37 PM , Rating: 2
That's not entirely accurate, the larger problem isn't the pressure of the burn pattern, it's the position of the piston, it's directional momentum at the time of ignition is opposite that of the expansion.


Two questions
By Spivonious on 5/21/2009 1:48:41 PM , Rating: 2
Why hasn't compression burn been used in gas engines before?

Can existing diesel engines use gas?




RE: Two questions
By FITCamaro on 5/21/09, Rating: 0
RE: Two questions
By Ammohunt on 5/21/2009 2:07:15 PM , Rating: 3
No you would get pre ignition(bad) becasue gas ignites at much lower compression then diesel. Similiar to octane ratings with gas they say to use a higher octane gas as you vehicle ages since carbon builds up on the pistons which reduces the combustion chamber size ever so slightly raising the compression of the cylinders causing pre-ignition(pinging).


RE: Two questions
By SublimeSimplicity on 5/21/2009 3:17:15 PM , Rating: 2
quote:
Can existing diesel engines use gas?


It depends... how many feet are you looking to go?


RE: Two questions
By FITCamaro on 5/21/2009 3:37:51 PM , Rating: 2
Haha!

A guy at work actually had a situation where he went to a gas station where the guy driving the refueling truck accidentally put diesel in the regular tank. So when he pumped his gas he was getting a mixture of regular and diesel fuel. Went to drive off and it didn't like it too much. Had to fight it out with the station and oil company to get his motor fixed.

Apparently the same day a local church refueled all their passenger vans and it f*cked all of them up too.


RE: Two questions
By theoflow on 5/21/2009 5:37:30 PM , Rating: 2
My best (right this second) analogy for difference between Gas vs. Diesel.

Imagine a generic blow up air balloon and the air inside of it to be the energy created by the engine. An engine is the storage and release of energy with each cylinder a 'balloon'.

If you blow up an air balloon too much, the pressure is so great that it'll eventually pop and release the air stored inside. This is kinda what Diesel engines do because the pressure causes the fuel to explode and release the energy.

With a gas engine, you can use an needle to pop the balloon as well to release the air/energy inside. So think of the needle as a spark plug in an engine as the method to release energy.

This is oversimplified, but covers the fundamental difference between gas vs. diesel.


Great Job
By lukasbradley on 5/21/2009 1:20:08 PM , Rating: 3
One of the best articles on DT in a while.




RE: Great Job
By Suntan on 5/21/2009 2:21:59 PM , Rating: 2
Too bad it didn’t give a more real world accounting of the technology.

By just reading the article, most people would believe that you will be operating in CI mode any time you are traveling slower than 60mph. That’s not going to happen. Further, HCCI is not applicable when the engine is under load (because they aren't able to control the process fast enough to eliminate distructive knock from occuring.) As it stands the technology is "almost" viable to move into regular development (which still means at least 4 or 5 years until you can buy it) for an engine to run HCCI when cruising at part load, but falls back to regular spark ignition at startup, high RPM or high load (which is most of the time unless you are out for a long Sunday drive on a 45mph road.)

Impressive tech for sure to be able to monitor and control explosions in a cumbustion chamber 1,500 times a second, but still not the panacea that Mick always tries to make the topics of his articles into.

…Oh, and if any of you out there have a current car that “injects fuel into a prechamber where the burn starts” for any sizable duration of time, you’re a$$ is going to be sitting on the roadside next to all kinds of problems going on under a hood that is billowing smoke.

-Suntan


RE: Great Job
By Amiga500 on 5/21/2009 2:27:25 PM , Rating: 1
Are you taking the piss?

I know Jason can only go from the source, but even so its poor!!! [Jason, IMO you should be asking some of the questions I am asking below - be more critical :-)]

What is the engine's specific power output (@3000rpm) how does it compare to sparked (and diesel engines)?
Torque curves relative to the same capacity sparked (and diesel) engines?
Fuel consumption with rpm relative to the same capacity sparked (and diesel) engines?

Sooo many unknowns.

Two or three figures in isolation means nothing. If the engine develops 30bhp at 3000 rpm and takes half a minute to get to 60 mph, would you all still be so impressed? There is no way of telling from this article how good the real performance is.

What if the touted performance improvement is at idle (say 900 rpm), but disappears as soon as you go over 1500 rpm?


RE: Great Job
By mindless1 on 5/21/2009 5:26:45 PM , Rating: 2
Didn't you see that the article is about a technology, not about one specific engine? If it were a finished product the article would've read completely different.


RE: Great Job
By Amiga500 on 5/22/2009 4:05:10 AM , Rating: 1
So what is the point of quoting 60 mph?

Absolutely none.

A figure in isolation means nothing.


"Toxic" Gasses
By Etsp on 5/21/2009 2:45:58 PM , Rating: 3
quote:
In early testing the engine deliver 15 percent better fuel economy and much lower NOx gas and CO2 emissions.

Uwe Grebe, GM's executive director of powertrain advanced engineering, says that the new engine greatly reduces these toxic gases.
I understand that these two statements are in different paragraphs, and so the "toxic gasses" that Uwe Grebe is referring to could be different than those mentioned in the previous paragraph.

However the way that these statements are organized, one would assume that Uwe Grebe is calling CO2 a "toxic" gas... It's plant food, it's something required for the entire ecosystem of earth to function. It's not "evil" or "toxic"... it may make the earth warmer, but it's not toxic.

So my question to Jason is, does Uwe Grebe think that CO2 is toxic, or was his quote used in a context that makes it sound that way?




RE: "Toxic" Gasses
By Jeffk464 on 5/21/2009 10:43:07 PM , Rating: 2
I do believe the EPA just got the right to regulate CO2. Its not toxic but it just might alter the earths climate. Great if you live in Canada, probably not good if you live in Mexico. :)


RE: "Toxic" Gasses
By AlexandertheBlue on 5/24/2009 1:58:04 PM , Rating: 3
quote:
Great if you live in Canada, probably not good if you live in Mexico. :)


Hey! Summers in the Toronto area are quite hot enough thank you!;)


"well North of 100mpg"
By Hulk on 5/21/2009 2:46:05 PM , Rating: 2
Coupled with a hybrid powertrain the article state small cars could get "well North of 100mpg."

Huh?

Right now the Prius get 50mpg. This engine is 15% more efficient. So that's 57.5mpg. Let's push it and say 75mpg. I'm wondering how you get "North" of 100mpg. Even a minicar like the Fit in hybrid form with this technology it would be hard to see 100mpg much less "North" of 100mpg.

And if RPM's is the problem, as it usually is with compression ignition engines, then why no use larger displacement engine to achieve the required power while limiting RPM. The electric motor/generator in the hybrid system could augment acceleration as it does today.

And finally how does the efficiency of this engine compare with a diesel? I have always thought the next step for hybrids was diesels. Of course the problem in the US is we crack our oil for all the gasoline available, leaving little diesel and of course higher prices than gas.

Just wondering. It's been a long time since I took "Internal Combustion Engines" as an engineer at Rutgers but I still remember a few things.




RE: "well North of 100mpg"
By werepossum on 5/21/2009 3:28:04 PM , Rating: 2
^^ If it's a plug-in hybrid like the Volt, the government uses formulae that assume a certain amount of driving powered by the battery pack. Thus you could have a car rated at 100 mpg that actually gets 60 mpg or 70 mpg, simply by assuming some of the mileage driven is powered from stored energy derived from AC household current. I don't know the exact formulae or what factors they take into account, but I do know that plug-in hybrid ratings can be quite misleading.


RE: "well North of 100mpg"
By Hoser McMoose on 5/21/2009 5:27:07 PM , Rating: 2
While the method of measuring fuel economy of plug-in hybrids leaves much to be desired, this HCCI technology would mate with them EXCEPTIONALLY well, particularly in the case of the Chevy Volt.

One of the key problems with HCCI engines is trying to match compression ignition to RPMs. In a conventional ICE engine you're RPMs are going all over the place. However if you're ICE engine as a generator to provide electricity to power an electric drive, as is the case in the Volt, then you're engine runs at only a single RPM rate.

Combine that with not needing any transmission at all and you can dramatically improve the efficiency of converting gasoline into moving the wheels and making the car go.

The technology should also work ok, though not quite as well, in a Toyota/Ford style parallel hybrid, though ironically enough it will probably struggle a bit in GM (or Honda's) current implementation of hybrids.


RE: "well North of 100mpg"
By fotoguy on 5/22/2009 9:58:48 AM , Rating: 2
I live in Missouri, and now a days, diesel prices are +- a few pennies of regular unleaded.

Also, diesel is becoming more available. I now have three fuel stations between me and the highway that now carry diesel that didn't five years ago.

Having said that, if we all started using diesel, its price would go up.


Noise?
By robertisaar on 5/21/2009 1:35:45 PM , Rating: 2
something that struck me: are these engines going to sound like diesel motors? if so, thats likely to put off a lot of people...




RE: Noise?
By Motoman on 5/21/2009 1:37:56 PM , Rating: 3
Not likely. Even the 5.9l HO Cummins Turbo Diesel in my 2004 RAM 3500 is very quiet. A small passenger-car-size motor, like what you would have in a VW, is I'm sure almost undetectable.

Cranky, clunky, noisy diesel motors are a thing of the past.


RE: Noise?
By Johnmcl7 on 5/27/2009 7:19:00 PM , Rating: 2
Very much so to the degree it's become a serious problem over here for hire cars - people are so used to diesel engines being loud and noisy that when they drive a modern diesel which is no noisier than a petrol engine they assume it's a petrol and fill it up with petrol.

Apparently the rate of diesel cars being filled petrol has risen considerably over the last few years as diesel engines have improved.


I find this article lacking.
By ziggo on 5/21/2009 5:45:27 PM , Rating: 2
And flat out wrong in places. Please, if you are going to bother posting these types of atricles, get someone with a the technical expertise to review them.

The first is direct injection. Traditional gas engines inject fuel into an intake, and the air-gas mix is then sucked into chamber, compressed, and finally ignited. Diesel engines put it directly into the combustion chamber, a more efficient process.

Expanding on this, since it is a tech site... The efficiency gains are from two things. One of which is common to a diesel.

1) No fuel intake allows for more valve overlap across the rev range, without blowing fuel into the exhaust. This leads to higher volumetric efficicency, and much better torque numbers, particulary low in the rev range.

2) Injecting gasoline during the intake stroke cools the charge as the fuel evaporates (heat of vaporization) reducing detonation, allowing some combination of increased boost (if forced induction), advanced timing, and running leaner afrs under power.

In a diesel engine, the compression of the gas/air mix triggers ignition, and the compression causes the combustion to be evenly distributed.

This is flat out false. In a diesel the fuel is injected during the power stroke, not compression stroke and is ignited nearly instantly by the high temeprature of the air due to compression. Combustion is not evenly distributed.

In early testing the engine deliver 15 percent better fuel economy and much lower NOx gas and CO2 emissions.

NOx emissions compared to what? A diesel or a gasoline engine? Also, CO2 emissions and fuel economy are the same thing.

Essentially this yields a gas-burning engine that runs as clean and efficiently as a diesel.

Diesels are dirtier than gasoline engines. They produce more NOx, and unburnt fuel (actual pollutants) due to the higher cylinder temps (NOx) and non-homogenous charge.

This article make absolutly no mention of the most significant reason diesels get better mileage while at partial power levels, the lack of a throttle. Since you are not pulling a large vaccuum in the intake at lower power levels, your pumping losses are greatly reduced. Has this been incorporated into these engines?

Neither article makes mention of this, and without this improvement, this technology will only be useful to reduce NOx emissions slightly and will not be as efficient as a diesel.




RE: I find this article lacking.
By menace on 5/21/2009 6:42:05 PM , Rating: 2
Wikip article has some good info http://en.wikipedia.org/wiki/HCCI

It has lower NOx than both gasoline and diesel. Lower Nox because the pre-mixed fuel-air mixture is homogeneous. You can also achieve lower NOx with a HCSI (spark ignition) which is essentially how this engine would operate when it has to light up the spark plugs.

What I don't get is what advantage is this versus Atkinson and Miller cycle engines which can also be done using variable valve timing. Prius uses Atkinson cycle which runs more efficient than Otto at expense of lower peak hp, which is not that important for a hybrid since the electric motor and batteries help balance loading. If you supercharge a four stroke Atkinson cycle engine then you can do a Miller cycle which both runs more efficient and can maintain the peak power of the Otto design.

Also they say 15% more efficient, which I assume is compared to standard 4 stroke Otto ICE. I have serious doubts about claims of it being better suited to hybrid application (vs. Atkinson cycle et al.), much less achieving a 100 mpg vehicle, unless the 'Obama-visioned' vehicle of the future (call it the people's car) is a teardrop shaped three-wheeled two seater that you drive while laying down on your stomach.


RE: I find this article lacking.
By HotFoot on 5/22/2009 12:16:18 PM , Rating: 2
I'd like to add that no mention in the article was made to the largest contributer to deisel's efficiency advantage over gasoline: compression ratio. The deisel cycle simply has a higher thermodynamic efficiency. That's #1.

However, the benefits mentioned in the article are still very interesting, at least in comparison to gasoline engines.


False statement in article
By ipay on 5/21/2009 11:26:42 PM , Rating: 2
Did a fairy wave it's wand to make lower emmissions?

"...but the new engine runs from 0 to 60 mph and from idle to 3,000 rpm at 2,900 degrees Fahrenheit (ignition temperature). This means that there are fewer pollutants..."

Not so. Lower ignition temp results in a dirtier burn. Read it in wikipedia :

http://en.wikipedia.org/wiki/HCCI

"Carbon monoxide (CO) and hydrocarbon (HC) pre-catalyst emissions are higher than a typical spark ignition engine..."




RE: False statement in article
By AlexandertheBlue on 5/24/2009 2:01:18 PM , Rating: 2
But lower NOx. NOx quantities are directly related to combustion temperatures.


RE: False statement in article
By darkpuppet on 5/25/2009 10:43:39 AM , Rating: 2
yes and no...

NOx is often reduced in modern engines by injecting an inert gas into the combustion chamber -- in most cases, through the EGR (which pumps CO2 from the exhaust gas back into the cylinder).

So while you make more NOx with higher combustion temps -- you can lower it's production through recycling the exhaust gases.

Where temps get worrysome in cars is in the pre-ignition of fuel (ping, detonation), and inability to cool the chamber to keep the metal from melting.


Internal Combustion Engines
By AntiM on 5/21/2009 2:16:13 PM , Rating: 2
I'm happy to see more progress on making internal combustion engines more efficient. However, I wonder if engineers will be able to design practical fuel cell that converts the energy in gasoline directly into electricity. It seems to me that using the energy stored in gasoline to basically produce heat is very inefficient.
In the not-to-distant future, I can imagine that the internal combustion engine will be thought of as a primitive waste of energy.




RE: Internal Combustion Engines
By mindless1 on 5/21/2009 5:34:19 PM , Rating: 2
It is unrealistic to think they can soon develop a fuel cell that can provide power at the rate an automobile needs and remain small and light enough. If we ignored size and weight, a fuel cell would seem a primitive waste of energy compared to a solar cell.

Maybe someday, but it will require funding, an infrastructure, and breakthroughs in tech that make it unlikely to happen in the "not too distant" future.


Glowplugs
By afkrotch on 5/21/2009 3:11:08 PM , Rating: 2
Will this engine need glowplugs or will it use the sparkplugs to start?




RE: Glowplugs
By Spuke on 5/21/2009 4:24:00 PM , Rating: 2
Spark plugs.


?
By winterspan on 5/22/2009 1:54:26 AM , Rating: 2
this is an idiotic article.. How in the world does the author think that the apparent "diesel vs gas-hybrid debate" is obsolete now that GM has a special gasoline engine that gets only 15% better mileage?

Not to mention that the obvious solution is a diesel-electric hybrid that gets the fuel efficiency benefits of both technologies.




RE: ?
By usbseawolf2000 on 5/22/2009 11:53:44 AM , Rating: 2
You won't see Diesel-hybrid until the cost of Diesel exhaust premium come down.

If hybridization of Diesel remove the need for the expensive exhaust system, it may make sense.


Hot is better...
By drwho9437 on 5/22/2009 9:56:55 AM , Rating: 2
Eff = 1 - 100/T roughly if it were close to ideal right...

So 1 - 100/3800 is better than 1 - 100/2900...

Also steel melts at 2500 F and Al at about 1200 F soooo they can't "run" at either temperature in the heat engine sense. In other words this post doesn't make any sense. I don't even know why I come here anymore.




RE: Hot is better...
By darkpuppet on 5/25/2009 10:46:44 AM , Rating: 2
Engines have cooling systems to keep the metal's temps down. As long as the metal is kept cool enough, the combustion temps can be as high as you want.

It's like filling a paper cup with water and putting a blow torch to the bottom of the cup. The cup won't burn so long as the water is able to absorb the heat energy from the flame.


"Can be used up to 60mph"
By Ozziedogg on 5/21/2009 6:06:36 PM , Rating: 3
... because if it reaches 88mph then it goes back in time.




Very good...
By INDVote on 5/21/2009 4:07:01 PM , Rating: 2
I remember reading about GM's work on this a few months back, and this is a great idea in a number of ways, fuel economy and greeness being only two of them. What' I'm interested to know is, does an HCCI engine require as stout a construction as a diesel engine? Diesel engines are notoriously very reliable, but also very heavy due to the extra reinforcement needed for compression ignition. I'd be curious to know if GM had to do a little/a lot/no extra reinforcement to get this to work.

These HCCI engines shouldn't sound like diesels. For one thing, all diesels (that I can recall) in passenger vehicles are turbo-based forced induction. These HCCI engines won't be from what I understand. Also, there's no indication here the HCCI engine will have a really low RPM ceiling, as diesels do. The design of diesel pistons is also different, as are a number of other factors.




By Jeffk464 on 5/21/2009 10:23:46 PM , Rating: 2
It will sure be nice to see GM be the first to market with something. Its been long enough.




By Randomblame on 5/22/2009 12:02:03 AM , Rating: 2
At 60mph it reverts to standard spark ignition, but at 88mph the flux capacitor kicks in and gets you to your destination before you even left. Naturally this technology was created by GM, if only they'd bring back the Delorian...




Misleading title
By usbseawolf2000 on 5/22/2009 11:50:36 AM , Rating: 2
Atkinson cycle spark ignition gas engine has been achieving Diesel-like efficiency since 1997 (introduction of Prius in Japan). The new 2010 Prius engine is about 40% efficient and redlines at 5,200 RPM. Top speed is 112 MPH.




Cold
By btc909 on 5/22/2009 3:59:11 PM , Rating: 2
HCCI doesn't work when the engine is still cold.




Why not diesel????
By TxRancher74 on 5/25/2009 9:02:03 PM , Rating: 2
I still don't understand why they just refuse to bring any of the nifty little cars and trucks powered by efficient, small diesel engines over here to the United States. They make cars TODAY that get upwards of 35-45 mpg on the highway and sell them in Europe, Asia, South America and Canada. I understand that people still have a bad taste in their mouths from the diesel Oldsmobile's and Buick's back in the early eighties, but come on......




By Johnmcl7 on 5/27/2009 7:22:01 PM , Rating: 2
"This problem has already been tackled by Ford (EcoBoost), GM and many others, and direct-injection gas engines will soon be all over the market."

Mitsubishi introduced their GDI engine way back in 1996 as have many others since then, unless I'm misunderstanding the statement above it's entirely misleading as those companies are actually amongst the last to have this technology.




Coates LTD
By msheredy on 5/21/2009 4:02:25 PM , Rating: 1
Can someone tell my why the fu¢k the auto industry isn't adopting Coates spherical rotary valve system???

www.coatesengine.com

Now this should be the future of our engines. The technology has been around for years and it's manufactured right here in the good old USA. GM, Ford anyone else out there—stop trying to invent something so complex that only yields marginal gains. Seriously