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The new technology was tested on a Caterpilllar heavy duty diesel engine. It achieved a thermal efficiency of 53 percent much better than the most efficient auto diesel engines (about 45 percent) and better even than the most efficient diesel engine in the world -- a turbocharged maritime engine that is 50 percent efficient.  (Source: Caterpillar Equipment)

The new engine could cut U.S. oil consumption by 4 million barrels a day -- roughly the amount that the U.S. imports from the volatile Persian Gulf.  (Source: Flickr)
New engine could get better gas mileage than mild hybrids even

Diesel and gasoline are both great fuels from a chemical standpoint, each with its own unique advantages.  Diesel burns more completely, lubricates the engine better, produces less carbon monoxide, and is safer as it does not produce as much flammable vapors.  However it has its disadvantages -- older engines can have a greater danger of incomplete combustion, overall engine power is a bit lower, and diesel engines weigh more.

Gasoline on the other hand burns faster and produces more power (due to the faster burn, not the energetic content).  However, it also typically yields worse gas mileage than diesel, combusts less completely (in well-maintained engines), usually requires a spark to ignite, and produces more pollutants and flammable vapors.

Researchers at the University of Wisconsin-Madison, led by Professor Rolf Reitz have come up with an innovative solution -- an engine which blends diesel and gasoline fuels to get the best of both worlds.  They have designed an engine which they say will be 20 percent more efficient than traditional gas engines, while also lowering the emissions.  The new engine works via a technique called "fast-response fuel blending", which means that the engine mixes the diesel and gas to the perfect ratio for the current conditions.

Heavy loads (like that of commercial trucks) would warrant a 85 percent gasoline to 15 percent diesel mix, while light loads would typically induce a roughly 50-50 mix.  Normally the gas wouldn't combust in a diesel engine, but by adding just the right amount of diesel fuel, combustion is achieved.  In fact, the special mix lowers engine temperatures by as much as 40 percent drastically reducing the amount of energy lost to waste heat.  This allows the diesel engine to use cheaper low-pressure injection (typically in gas engines only), and burns the fuel more cleanly, producing less pollutants.

The researchers estimate that if all cars and trucks in the nation adopted the new engine, it would cut U.S. oil consumption by a third -- by 4 million barrels per day.  States Professor Reitz, "That's roughly the amount that we import from the Persian Gulf."

The engine was developed using theoretical models, then built using a Caterpillar heavy-duty diesel engine as a base.  The new engine achieved 53 percent thermal efficiency, an admirable result, considering the best diesel engine -- a massive turbocharged two-stroke used in the maritime shipping industry -- gets 50 percent.

Professor Reitz concludes, "For a small engine to even approach these massive engine efficiencies is remarkable.  Even more striking, the blending strategy could also be applied to automotive gasoline engines, which usually average a much lower 25 percent thermal efficiency. Here, the potential for fuel economy improvement would even be larger than in diesel truck engines.  What's more important than fuel efficiency, especially for the trucking industry, is that we are meeting the EPA's 2010 emissions regulations quite easily."

The one major downside is that the engine necessitates a second tank.  However, in order to meet EPA nitrous oxide emission regulations the only alternative for large diesel vehicles would be urea injection -- which would likely be more expensive, less efficient, and still require a second tank.  While there's no telling how soon the engine will start popping up in cars and trucks, it appears to be the best solution yet and the best alternative to mild hybrids.  Of course it could be combined with hybrid electric technologies for even great fuel efficiencies.



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well but for vehicle usage
By VultureTX on 8/4/09, Rating: 0
RE: well but for vehicle usage
By tastyratz on 8/4/2009 10:32:22 AM , Rating: 5
not necessarily. Diesel engines today aren't the same as the ones of yesteryear. There is a great likelihood that this will fit in your standard engine bay around the same size as any other engine. The only difference is a fuel mixing that takes place - likely some sort of regulator/splitter right at the fuel rail. While more complex its not that much different.
For example as well: The jetta and jetta tdi are reported as being the same weight on msn auto's

Today's diesel is EXCELLENT,and FUD like that is why its not so widespread in the states. Its extremely comparative.

Also, if your afraid of gas tank size... who said you need to carry more fuel? You just need DIFFERENT fuel... so you would likely have a dual spout on the side and run 2 half sized gas tanks (or 60/40 or whatever they choose to go with for the split)... if you have 1 15 gallon tank or 2x 7.5 gallon tanks you have the same qty of fuel overall. Because of the staggering increase of efficiency however you will likely see this used frequently in sub compacts with SMALLER gas tanks achieving the same range.

The question with this is if we will see adaptations at the pump to idiot proof a system like this... and are people competent enough to monitor 2 gas level gauges. What happens when it runs out of 1 fuel, can it limp home on the other?


RE: well but for vehicle usage
By JediJeb on 8/4/2009 10:50:42 AM , Rating: 5
With lower compression as stated in the article if you also include a spark plug in the design then you should be able to make it running on 100% of either fuel when needed.

This reminds me of what International Harvestor did back in the late 40's early 50's with their farm tractors. They had a small Gasoline tank, and a larger Kerosene tank. You started the engine on gasoline, then once it was hot switched to kerosene. Kerosene is about half way between gasoline and diesel on flamability/volatility so it would be similar to this mixture. Back in the 40's kerosene was cheaper than gasoline so this made sense to farmers. The engine would not start using kerosene because when cold it would not vaporise well enough to iginte, but once the engine was hot it ran great. I wonder if this is where they got the idea?


RE: well but for vehicle usage
By tastyratz on 8/4/2009 10:58:03 AM , Rating: 5
Actually you bring up another VERY valid point without realizing it:

This engine actually opens up the possibility of using a 100% biofuel diesel.

The issue with a lot of fat based biodiesel is solidification at lower temperatures... but if the engine can start and warm up on gasoline every time they can run coolant lines parallel with the diesel fuel line and back to the tank to heat it up. Then when the engine is up to temperature they can switch over and begin blending. A lot of biodiesel conversions do this manually with switches... but this really opens up the possibility to do it from the factory intelligently.


RE: well but for vehicle usage
By AEvangel on 8/4/2009 12:07:06 PM , Rating: 5
Yeah it would be nice if this was pursued more as a viable option, I know of a couple of local Midwest based VW TDI owners that use 100% Bio-diesel, they have a small like 2.5 gallon tank installed in their trunk for regular diesel to start their car on then flip a switch and start running on the 100% Bio-diesel that they make in their basement for like half to a third of the price of regular diesel.


RE: well but for vehicle usage
By Lord 666 on 8/4/09, Rating: -1
RE: well but for vehicle usage
By quiksilvr on 8/4/2009 2:15:48 PM , Rating: 2
What does that have to do with anything? Did you think people would actually rate that up or do you get off posting stupid comments to see if the -2 rating exists?


RE: well but for vehicle usage
By FITCamaro on 8/4/2009 3:12:26 PM , Rating: 2
Given the poster, I would assume he was joking.


RE: well but for vehicle usage
By Lord 666 on 8/4/09, Rating: -1
RE: well but for vehicle usage
By RivuxGamma on 8/4/2009 9:54:10 PM , Rating: 3
Biodiesel sounds nice and all, but it does produce more CO2 and more nitrogen oxides when burned than normal diesel.

I'm a bit skeptical of the findings, anyway. There's just plain less energy in the mixture when diesel is mixed with gasoline, regardless of how it's burned. It's possible that it's only something that can work in gigantic engines and the article does say that it's expensive.

I'll wait until there's further proof of this technology before I hang my hat on it.


RE: well but for vehicle usage
By Samus on 8/5/2009 10:40:03 AM , Rating: 2
a golf tdi is 179lbs heavier than a golf 2.5, and the golf 2.5 doesn't even have a turbo.


RE: well but for vehicle usage
By Amiga500 on 8/4/2009 12:53:43 PM , Rating: 2
Yup.

Ferguson did the same with TVO on the TE20 - a mix of petrol and paraffin - to start the engine, and diesel as a regular runner.


RE: well but for vehicle usage
By rudolphna on 8/4/2009 11:15:44 AM , Rating: 2
We already have one. I live in upstate new york, we have alot of diesel pumps up here at gas stations. The diesel nozzle is much thicker around than the gas one does, and won't fit in. I know this, because one day I wasn't paying attention, and picked up the diesel nozzle, and it didn't fit. Good thing. I would have been stranded at HESS till I could get my tank drained. DOH. The real problem is going to be keeping people from putting gas in the diesel tank. Maybe a square nozzle for Gas, big round one for diesel, or something.


RE: well but for vehicle usage
By Lord 666 on 8/4/2009 12:37:43 PM , Rating: 2
There are actually two sized diesel nozzles; one for cars and the higher rate intended for trucks.

While I understand the idea behind it, as diesels become more popular, they do need to standardize on size/form factor. Driving to and from Florida last year, came across one station that only had the large nozzle off of I85. Other than that, all other stations have the smaller and some have both.


RE: well but for vehicle usage
By tastyratz on 8/4/2009 3:08:48 PM , Rating: 3
well that's just it. While we have one now, its usually seperate. Filling a tank like that would be cumbersome and generally loathed by the public.

A dual feed single connector fuel nozzle that plugged in 1 way with 2 outlets would be a good adaptation if enough manufacturers agreed to make these engines with a true market penetration.


RE: well but for vehicle usage
By monomer on 8/4/2009 4:57:54 PM , Rating: 2
Lots of older model Ford Trucks had dual gas tanks, and I realy never heard anyone complaining about them. In fact, some guys loved them since they could just run two pumps and fill in half the time than if they had only one tank.


RE: well but for vehicle usage
By MrPoletski on 8/5/2009 3:38:58 AM , Rating: 3
Here in the UK we simply colour code the pumps, green is unleaded petrol, red (used to be) 4 star leaded and black is diesel.

The nozzles are the exact same size.

If you screw up and put the wrong fuel in your car, it's your own stupid fault.


RE: well but for vehicle usage
By axeman1957 on 8/5/2009 11:59:49 AM , Rating: 2
Pretty sure the US does that too... every diesel pump I have ever seen has been green, and the unleaded are black


RE: well but for vehicle usage
By MrPoletski on 8/6/2009 5:26:42 AM , Rating: 2
quote:
Pretty sure the US does that too... every diesel pump I have ever seen has been green, and the unleaded are black


uh-oh, opposingly colour coded pumps, that's a recipie for disaster if coming over here to visit;)

but that's ok, we don't mind foreigners breaking their cars over here and having to pay our mechanics to fix it :)


RE: well but for vehicle usage
By Spuke on 8/5/2009 1:04:08 PM , Rating: 2
quote:
The nozzles are the exact same size.
The nozzles are a different size here but the color coding is the same.


RE: well but for vehicle usage
By teldar on 8/4/2009 3:54:52 PM , Rating: 4
There you go with the logic and truth about diesels. Don't know what you're thinking.....

Realistically, I don't understand how someone can be alive today and posting on this site and not have ever heard of BMW, Mercedes, or VW diesels.

Incredible.

Apparently these cars are NOT too heavy to accelerate decently or get decent mileage.


RE: well but for vehicle usage
By tjr508 on 8/4/2009 5:06:12 PM , Rating: 2
They don't travel a million miles like an International either...


RE: well but for vehicle usage
By Ammohunt on 8/5/2009 3:51:08 PM , Rating: 2
you absolutely correct, I have personally driver on the german autobahn 140Mph in a na Audi with a 1.9L turbo diesel man that car hauled ass 140Mph at 3k rpm.


RE: well but for vehicle usage
By kattanna on 8/4/2009 12:02:54 PM , Rating: 2
the thing that scares me most about this is having 2 different fuels.

when i pull up to the pump, sometimes i see people who look like they are confused with 2 pump handles at the same pump, gas and diesel. but now.. they might have to use both, and i can EASILY see people putting the wrong gas into the wrong tank.


RE: well but for vehicle usage
By mvpx02 on 8/4/2009 1:32:06 PM , Rating: 2
If this takes off, I'd imagine we'll see a standard pump nozzle for it too... something with 2 seperate spouts next to each other.

Think of the positive & negative terminals on an electric plug, they go into seperate holes and 1 is too big to fit into the smaller hole, so there is only 1 way to fit it in.


By wetwareinterface on 8/5/2009 1:09:27 AM , Rating: 2
that's the beauty of this engine in case you missed it in the article it can run on 100% gas or a mixture of gas and diesel. if some tard at the pump puts gas in his diesel tank side by accident he simply can drive till the gas is gone from the diesel tank if the manufacturer of the engine puts in a fuel sensor or the engine sensor registers too much of a power increase over what it's predicting for the fuel mix to be and assumes it's got gas in the diesel tank. diesel is thicker at lower temperatures than gas and can be sensed by flow and pressure required at the fuel pump. add in a temp gauge to the onboard engine computer and it could easily calculate if gas is in the diesel tank and come close to measuring the current fuel's mixture levels by the pressure level at the fuel pump and flow rate at the mix nozzle


Laws of Thermodynamics?
By Shining Arcanine on 8/4/2009 9:49:31 AM , Rating: 2
I thought that the laws of thermodynamics limited an engine to 50% efficiency unless it used the Carnot cycle.

How is it possible for them to achieve 53% efficiency by mixing fuels?




RE: Laws of Thermodynamics?
By axeman1957 on 8/4/2009 9:55:49 AM , Rating: 5
They probably tied the spark plugs to the flux capacitor


RE: Laws of Thermodynamics?
By therealnickdanger on 8/4/2009 10:12:54 AM , Rating: 3
Axeman! You're not thinking 4th-dimensionally!

You're forgetting how the flux capacitor must be powered. Thankfully, we now have Black & Decker's Mr. Fusion. No more stolen Libyan nuclear fuel, no more lighting strikes, no hyper-combustable locomotive logs!


RE: Laws of Thermodynamics?
By axeman1957 on 8/4/2009 10:20:35 AM , Rating: 5
Personaly, I am a fan of the arc reactor... I think Doc Brown should make a cameo in Iron Man II


RE: Laws of Thermodynamics?
By therealnickdanger on 8/4/2009 2:53:17 PM , Rating: 3
ZPMs own all.


RE: Laws of Thermodynamics?
By TSS on 8/4/2009 6:38:38 PM , Rating: 2
Not if Zefram Cochrane has his way.


RE: Laws of Thermodynamics?
By jawqn8 on 8/4/2009 10:05:12 AM , Rating: 5
You are both correct and incorrect. The Carnot cycle efficiency is calculated between the two operating temperatures. The Temperature that the engine burns the fuel at is called Th and the temperature that the engine rejects heat, or the outside air, is called Tc. Th is the hot temperature and Tc is the cold temperature. The equation is then Efficiency=1-(Tc/Th). That will give you the effiecency of the Carnot cycle. The temperature that you use will have to be in Kelvin to get the correct answer.

If you assume that the temperature outside is 70 degrees F and the gasoling burns at 1500 degrees F. The maximum efficiency that they engine can achieve would be 73%. The Carnot cycle uses the two temperature extremes to calculate efficiency. If you run the math for the same operating temperature but a lower environment temperature than your efficiency should increase because there is a larger difference in temperature. For example, if the temperature outside is 0 degrees F and the gasoline still burns at 1500 degrees F the efficiency is now calculated to be 75%.


RE: Laws of Thermodynamics?
By mars2k on 8/4/2009 11:08:13 AM , Rating: 2
Thanks for the info. Keep it up


RE: Laws of Thermodynamics?
By Jimbo1234 on 8/4/2009 2:10:43 PM , Rating: 2
quote:
The temperature that you use will have to be in Kelvin to get the correct answer.


You can also use the Rankine temperature scale. It's a less messy conversion from F (just add 459).

Rolf Reitz was my class selection advisor when I was getting my ME degree at the UW. Small world.


RE: Laws of Thermodynamics?
By Keeir on 8/4/2009 3:53:52 PM , Rating: 2
In further answer

A Carnot Cycle is the maximum efficiency cycle for any heat engine.

However, there are numerous types of cycles. Otto, Atkinson, Diesel, etc.

Given they started with a Diesel Engine, I think this is a modified Diesel Cycle. Probably raising the flame temperature while maintaining higher compression ratio.


RE: Laws of Thermodynamics?
By Fritzr on 8/4/2009 6:16:41 PM , Rating: 2
Carnot cycle is a pure heat transfer engine. This cycle is used today with a slight addition to the original design. Google "Sterling Cycle Engine"

More importantly the thinking that led to the Heat Powered engine is Carnot's research into the energy cycle. He proved that the maximum amount of energy available is 100% of the input energy and that the actual output was equal to input-(losses+inefficiencies).


RE: Laws of Thermodynamics?
By PhoenixKnight on 8/4/2009 10:06:56 AM , Rating: 2
Maybe they also mix in some magical pixie dust.


RE: Laws of Thermodynamics?
By Fritzr on 8/4/2009 6:10:11 PM , Rating: 2
Carnot proved that the absolute maximum is 100%. Any loss along the way reduces the efficiency. That is, the 'lost' energy produuced is diverted to powering the loss instead of the Power Take Off. If the fuel is converted to energy with less than 100% efficiency, then that difference also is added to the waste percentage.

So waste heat, friction, less than perfect combustion etc. is subtracted from the 100%.

This fuel mixture reduces the waste factors enough to allow a modified truck engine (the Caterpillar) to reach 53% efficiency. The 50% limit you refer to is simply the previous best with an ICE engine.


Very cool!
By chunkymonster on 8/4/2009 11:41:15 AM , Rating: 2
I'm all for any technology that increases mpg and reduces emissions. Generally speaking, Americans need to get off the "diesels suck" band wagon and realize the efficiency and benefits of clean diesel engines and diesel engine hybrids.

The article linking to the 50mpg Audi TT with a top speed of 140mph is an excellent example of how diesel needs to and should be viewed by the American car buyer.

VW Jetta TDI FTW!!!!!!!!!!!!




RE: Very cool!
By 91TTZ on 8/4/2009 12:05:31 PM , Rating: 3
quote:
The article linking to the 50mpg Audi TT with a top speed of 140mph is an excellent example of how diesel needs to and should be viewed by the American car buyer.


An article about a 50 mpg Audi TT would be misleading to the American car buyer. If you took that same 50 mpg car from Europe and put it on our streets the American car buyer would notice that it only gets a little more than 40 mpg. Why? Because the imperial gallon is larger than the US gallon.


RE: Very cool!
By joos2000 on 8/4/2009 11:12:34 PM , Rating: 3
40 mpg is still an excellent result for a sports car.


RE: Very cool!
By FITCamaro on 8/4/2009 3:14:37 PM , Rating: 3
Imagine though if you could have the torque and mpg of a diesel, and the horsepower of a gasoline engine. I'm not sure if it can work that way though. Transition from one fuel to another as rpms rise.


RE: Very cool!
By Keeir on 8/4/2009 3:34:33 PM , Rating: 2
I think.... from reading the article, the Engine would essentially "revert" to Diesel like operation at low power demands. You would only get the mpg of a diesel (actually even better) at steady state operation. Accelerating would get you the power of gasoline, but at much closer to gasoline mpg. Torque would be up in the air... I think it could probably be tuned to give closer to an ideal torque-->power transition since essentially your burning the "ideal" mixture at any one time.


RE: Very cool!
By Johnmcl7 on 8/4/2009 3:52:52 PM , Rating: 2
You don't need the horsepower of the petrol engines, the diesels do just fine on their own - while on paper they may look slower due to being down on power and slower 0-60, their fast midrange acceleration makes up for it. The Skoda Fabia VRS has a 130bhp 1.9 TDI PD engine (VW), it was able to outpace its Mini Cooper rival on the racetrack due to its straightline speed and is faster than a BMW 330i 50-70 despite being slower 0-60.

Seat currently run diesel Leons in the WTCC (they run under the same rules as the petrols), they took the manufacturer's championship last year and look to do the same this year as the petrol powered BMW's have been unable to match the performance of the Leons. Rather oddly BMW have been complaining about the Seat diesel engines despite making some outstanding diesels for their roadcars at the moment.

Diesel performance in Le Mans hasn't been too shabby either, a petrol car hasn't won it for a while and even rules put in places to reduce performance of the diesel cars hasn't stopped them winning


RE: Very cool!
By FITCamaro on 8/4/2009 9:56:09 PM , Rating: 3
A diesel only revs to 5000 rpm tops. If the motor can transition from diesel to gas as rpms rise, then it can rev to 6-7000 rpm like a normal motor. Thus increasing the powerband of each gear.


RE: Very cool!
By mindless1 on 8/9/2009 6:45:35 PM , Rating: 2
0-60 is largely irrelevant for mass consumer automobiles, no sane person floors it from 0 to 60 out of need unless it's a very rare situation.

How odd it is that people are thinking performance, as if they fancy themselves race car drivers. That's the opposite of good fuel economy, self-defeating sillyness.


RE: Very cool!
By DeepBlue1975 on 8/5/2009 9:59:24 AM , Rating: 2
There are some european models that achieve this.
For example, BMW's 1 series Diesel version is the same size as its gas counterpart (2 liter) and features 177bhp versus 170bhp that the gas version has.
The mileage is much better on the diesel one as the torque figure is... The only disadvantage is that you get a slightly noisier engine (you'll only notice that when outside the car in practical situations), and that the diesel engine does not rev as high as the gas one (I don't consider this a disadvantage at all, rather a simple difference).

And also diesel cars usually outlive their gas counterparts, even though the maintenance costs are a bit higher (the oil changing intervals and other routine maintenance tasks do have shorter intervals than on gas versions).

I like diesel better than gas. More efficiency, less need to rev high to get a good performance (talking about high power diesel engines, and not older designs that only had great mileage but also really awful performance figures), and they don't sound nearly as crappy as they did some years ago.

Nevertheless I would think that from a pure cost-benefit standpoint, this new breed of "gasesel" engines isn't as promising as using pure diesel engines is.
For transitional purposes (I mean: transition towards alternative fuels), all electrics and gas/diesel electric hybrids look as a better path of development in the long run, at least IMO, and even though those technologies are priced on the steep side as of now.


RE: Very cool!
By Major HooHaa on 8/7/2009 7:28:25 AM , Rating: 2
Diesel engine hybrids? Then look at the link I found.

Volkswagen to introduce 70 mpg Diesel-Electric Hybrid Golf.

http://www.treehugger.com/files/2008/02/volkswagen...

I would agree that modern diesel's are impressive. But I saw Top Gear's review of the new Honda hydrogen fuel cell car and thought that hydrogen fuel cells may be the way to go.

An early prototype car with average performance and that produces only water vapour has got to be a good thing.


RE: Very cool!
By Major HooHaa on 8/7/2009 7:42:06 AM , Rating: 2
Darn, I just noticed the age of the article and the fact that VW cancelled the diesel hybrid in favour of the Golf 1.4 TSI engine, because the diesel hybrid was too expensive. Well that's capitalism for you... Profit comes first.

I hope they don’t give up on the hydrogen fuel cell car.


RE: Very cool!
By Major HooHaa on 8/9/2009 7:13:45 AM , Rating: 2
An update, I have been trawling the 'net, looking at Hydrogen Fuel cell stories and this is some of the stuff I found. Apparently it takes lots of energy to split the hydrogen and oxygen that make up water... Then I found a story about splitting water molecules at room temperature using aluminium.

Shocking: Aluminum Producing Hydrogen from Water – Almost Free Energy!
http://www.greenoptimistic.com/2009/01/24/hydrogen...

Honda makes first hydrogen cars.
http://news.bbc.co.uk/1/hi/business/7456141.stm

Hydrogen-powered centre proposed.
http://news.bbc.co.uk/1/hi/scotland/edinburgh_and_...


variable octane
By phorensic on 8/4/2009 12:15:52 PM , Rating: 2
So would this be considered variable octane technology?




RE: variable octane
By Motoman on 8/4/2009 12:35:23 PM , Rating: 4
No, especially considering that diesel doesn't really contain octane molecules. Diesel is rated by it's cetane molecule content.


RE: variable octane
By phorensic on 8/4/2009 12:46:12 PM , Rating: 2
Noted, but you could say you can control the burn rate based on the mix. I think this is probably a dream for a race car motor designer. They tend to use high octane fuels but have to compromise the design/tune of the engine around the octane. Imagine if they could have a variable octane fuel, they could probably make more power over a more broad range. I know I keep using the word octane, but do you see what I mean?


RE: variable octane
By Motoman on 8/4/2009 12:55:59 PM , Rating: 2
I see what you're getting at, but I'm not sure it works out that way...

You're going to set up the compression ratio for whatever fuel you intend to run. In some sports, there's even a spec fuel, so you don't have much doubt what fuel that's going to be.

I am not aware of any reason why you'd want to variably change the burn rate of your fuel, because then you'd be also wanting to dynamically change your compression ratio...as far as I have ever heard, and I've been involved in racing for about 30 years now, there is a given compression ratio that is ideal for a given fuel, regardless of whatever else is happening. So I don't think there's an obvious reason to want to muck with the nature of your fuel during runtime.


RE: variable octane
By phorensic on 8/4/2009 1:17:43 PM , Rating: 2
There has to be some type of advantage. We have made intake and exhaust valve duration and lift completely variable, we have ignition timing *curves*, some manufacturers go through great lengths to put in variable length intake manifolds, Toyota has that VVIS tech, turbochargers now come with variable turbine blades. While injecting fuel is varied to get the right AFR, what is still static is the octane/burn rate, etc. Why not play around with that variable too?


RE: variable octane
By Motoman on 8/4/2009 1:31:24 PM , Rating: 2
I guess I don't have a scientific answer for you...just doesn't feel right to me that you'd want to mess with that. Interesting question though...I have a buddy of mine who's one of the top 2-stroke design guys in North America (he gets contracted by companies like Bombardier to do 2-stroke design work)...next time I talk to him I'll see what he thinks.


RE: variable octane
By Jimbo1234 on 8/4/2009 2:26:25 PM , Rating: 2
Variable turbo geometry is for a different purpose. Turbines are most effective running at a specific constant speed and drop off rapidly when you devivate from that. The vane angle determines that speed. Having a variable vane turbo allows higher efficiency over a larger speed range, therefore reducing turbo lag.


RE: variable octane
By phorensic on 8/4/2009 3:16:41 PM , Rating: 2
The same way having a variable burn rate would allow a higher efficiency over a larger RPM/load range....right? That's what I was getting at.


RE: variable octane
By Alexvrb on 8/5/2009 12:14:17 AM , Rating: 2
Lets say you've completely tuned a motor to make the most out of 93 (R+M) octane, and you've got some magical way to dynamically move from 93 to 87 and anywhere in between. When you dynamically lower the octane rating of the fuel, you have to correspondingly alter valve timing, ignition timing, compression ratio (magic), and air induction (if applicable). But then all you're really doing in the end is lowering your power output as you drop the octane rating. If only there was some other way to reduce power output... oh yeah! Reduce how much gasoline you're dumping in.

Really, there might be efficiency benefits, I don't know. But you brought up a race car engine, which implies wanting maximum performance. You build the motor to get the most out of the fuel available/allowed. If you do ANYTHING that alters the octane or combustability of the fuel downward (the only possible direction when they limit *and/or test* your fuel's content) it can only serve to reduce power. Which you can also do by backing off the accelerator.


RE: variable octane
By Spuke on 8/5/2009 1:21:56 PM , Rating: 3
quote:
But then all you're really doing in the end is lowering your power output as you drop the octane rating.
Higher octane does not provide more power, it increases knock resistance which allows more power.


RE: variable octane
By Black69ta on 8/9/2009 1:30:27 AM , Rating: 2
Agreed, the popular myth oil companies like to spread is that premium fuel makes more power in your grocery getter. They tell us this to sell more premium unleaded. In reality, Octane is only a Rating, an it measures the resistance to pre-ignition, detonation, or knocking. octane and flame speed has nothing to do with power production. Compression ratio determines the required Octane. Higher compression ratios requires higher octane ratings to avoid detonation. But, different engine designs tolerate different octanes for the same compression ratio. Not sure where I saw it but a few years ago Saab or Volvo experimented with a variable compression engine.


RE: variable octane
By JediJeb on 8/5/2009 12:11:42 PM , Rating: 2
The octane and cetane ratings are not actually based on the content of those compounds in the fuel, but how the fuel burns in relation to those compounds, including btu value and auto ignition tendency. If you run low octane fuel in an engine with too high compression the fuel ignites before the spark plug fires, causing pre-ignition which can damage the engine or lower efficency.


The devil is in the details...
By Beenthere on 8/4/09, Rating: 0
RE: The devil is in the details...
By SiliconJon on 8/4/2009 10:14:24 AM , Rating: 1
More likely the story, and its technology, will disappear for whatever reason (good theory/bad practice, IP gobbled up by other interests, just hype to begin with prior to a fundraiser...) Whatever happened to that high school mechanic shop that had a 50mpg sport diesel?


RE: The devil is in the details...
By 91TTZ on 8/4/2009 10:40:37 AM , Rating: 3
Usually press releases quote their most optimistic predictions. By the time it's more thoroughly tested, real world results usually show that it's not any better than what's currently out there, or the improvement isn't worth the added cost.

For ideas that do actually offer an improvement, they usually do catch on, such as hybrids.


RE: The devil is in the details...
By drewsup on 8/4/2009 11:04:58 AM , Rating: 2
RE: The devil is in the details...
By 91TTZ on 8/4/2009 11:58:28 AM , Rating: 2
Keep in mind that the article is using British measurements, and they use the imperial gallon. The US gallon is smaller. So 50 miles per imperial gallon would be closer to 40 miles per US gallon.


RE: The devil is in the details...
By Spuke on 8/5/2009 1:39:06 PM , Rating: 2
It only does 0-60 in 7.5 sec. Now I realize that this is only one aspect of a cars performance, but considering the potential cost of this car, it should be faster. BMW's 335d is quicker and probably cheaper although it would get 5-6 mpg less. The fuel economy difference isn't worth the performance penalty IMO. I read of some euro tuners getting 340 hp and 500 lb-ft of torque out of the 335d. There are some US tuners currently working on the US 335d's, apparently the US 335d uses a different ECU than the euro one's. Can't wait to see what happens on this front.


By Jimbo1234 on 8/4/2009 2:28:30 PM , Rating: 2
IP will be maintained by WARF.


lol
By Breathless on 8/4/2009 11:00:59 AM , Rating: 5
"53 percent much better than the most efficient auto diesel engines"




RE: lol
By bobsmith1492 on 8/4/2009 11:35:15 AM , Rating: 3
That should be:

"53 percent, much better than the most efficient auto diesel engines"

Based on the context, that is my interpretation.

The other interpretation could be:

"53 percent better than the most efficient auto diesel engines"

However, that does not jive with the rest of the article.

Ya gotta love grammar. :)


Good stuff...
By retrospooty on 8/4/2009 9:44:18 AM , Rating: 2
Not neccisarily this, but in general new tech will be the way out of this mess.




By The Imir of Groofunkistan on 8/4/2009 10:13:25 AM , Rating: 2
what mess?


Wrong
By Roy2001 on 8/4/2009 1:07:37 PM , Rating: 2
"it appears to be ...the best alternative to mild hybrids". This is completely wrong. They are not alternatives to each other!

Hybrid technology like the one used by Prius would reduce polutions and increase MPG for city drive! These 2 technologies need to be combined!




RE: Wrong
By Alexstarfire on 8/4/2009 2:39:00 PM , Rating: 2
Quite correct. I don't know why people think they are mutually exclusive. In fact, they should be mutually INCLUSIVE.


Wow
By Laereom on 8/4/2009 9:46:24 AM , Rating: 2
That sounds pretty sweet.




it might work and it might not
By kg4icg on 8/4/2009 10:01:12 AM , Rating: 2
If the engine in the picture is the 1 they were using then there might be a problem. For 1 that is a 3408 Cat which isn't used on Over The Road Trucks anymore since the 1990's.

It is mechanically injected with a distribution injector pump. Todays diesels in big trucks have Electronically fired injectors with a constant pressure pump and they are 4 stroke diesels. Plus direct injection right into the combustion chamber also.

According to the article they got this to work on older 2 stroke diesels with mechanical fuel injection systems. I think they should try testing on the modern 4 stroke diesels before they get to excited and have it blow up in there faces big time.




I Tip My Hat
By clovell on 8/4/2009 10:49:49 AM , Rating: 2
I gotta tip my hat to these guys. For the last few years, I've felt that Series PHEV's were the way to go. But, after seeing a return to ~$2.50/gal gas, a $40k+ pric tag on the Volt, and now this... I'm gonna have to line up with FIT and say that there's still a lot of headroom in terms of efficiency with ICE. Nice job, UW - Madison.




Multi-fuel
By enigmamgine on 8/4/2009 10:57:37 AM , Rating: 2
This appears to be very similar to propane injection in diesels.

The basic idea is the Propane will not auto-ignite so diesel is injected to "light" the Propane. Very similar to how gasoline works, where the spark plug "lights" the fuel.

Propane works quite well in the Diesel engine, I get approximately 19MPG on Propane and over 40MPG on Diesel. The "Devil" in those details is Propane has far fewer BTU's than Diesel, so my combined mileage isn't what you'd think.

Basically if I can get Propane at or below 2/3 the cost of Diesel it's a net gain, anything else and I just enjoy the additional power the Propane affords me (about 100 extra HP in my application). Obviously those are empty numbers, as I pull more weight the % of Diesel to Propane shifts dramatically, but still the Propane does give a nice kick in the available power.

Using that theory you could technically inject gasoline and at the appropriate moment "light" it by injecting diesel and potentially see the same (if not greater due to gasoline having more BTU's) benefits as Propane injection.




I don't get...
By Motoman on 8/4/2009 11:27:18 AM , Rating: 2
...how this really works from a practical standpoint...

The flashpoint of both fuels is wildly different...and a diesel motor runs at a way higher compression ratio than you want with a gas motor, as part of the detonation-ignition process.

I don't doubt that they somehow got this working...but the physics just seem off to me. Seems like if you put gas in a diesel motor, it would explode...

I would think it must run at a lower compression ratio that a regular diesel...and am tempted to wonder if they worked out some way to have variable compression, maybe with some kind of relief valve or something like an exhaust valve on a 2-stroke MX bike to chage the volume of the squish chamber.




LPG and diesel
By William Gaatjes on 8/4/2009 1:07:47 PM , Rating: 2
I wonder if the researchers know about the lpg/propane diesel technology. This technology is used also for heavy duty trucks. For personal vehicles it is unfortunately rare.

More horpsepower and less pollution. A win win situation it seems.

http://www.chilterngascars.co.uk/cars/lpgdiesel.ht...

http://autospeed.com/cms/title_Diesel-LPG-an-Amazi...




I like the idea, but...
By Jeff7181 on 8/4/2009 3:55:54 PM , Rating: 2
I think this is something that wouldn't be cost effective for the average Joe. There's no question we can make more fuel efficient engines, the question is at what cost? Diesel engines are not cheap to begin with and when you're talking multiple fuel tanks and mixing valves and fuel pumps and injectors and the electronics to make it work, you're likely talking about vehicles that cost 30-50% more than their plain gasoline equivalent.

Where this would make the most sense, in my opinion, is fleet vehicles. USPS, UPS, FedEx, taxi's, buses... all rely heavily on relatively small vehicles and could more easily get a return on their investment in a delivery vehicle that costs more than a plain gasoline or diesel engine.

In Ann Arbor, MI they already have hybrid diesel-electric buses and I'm pretty sure they use part biodiesel. Imagine a hybrid biodiesel/gasoline-electric bus, lol. I wonder what that would cost and how efficient it would be compared to a plain diesel engine they'd normally put in a bus.




Micro turbine electrics
By 2tweeked on 8/5/2009 1:58:11 AM , Rating: 2
This is a wonderful article! Diesels are fantastic engines. True efficient workhorses. Locomotives have used diesel electric hybrids for over 3 decades. The automotive industry should have taken notes from the locomotive industry.

Piston engines have many moving parts and many points of mechanical failure and maintenance. I propose the hybrid electric automotive industry to diverge from piston engines to micro-turbines. Micro-turbines are multi-fuel and only have 1 major moving part, the turbine. The turbine is compact and powerful.

Don't take my word for it. Being green doesn't mean lame in performance.

http://greenstockscentral.com/capstone-cpst-integr...

It is something to consider and I think this type of manufacture retooling would be profitable in many aspects.




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