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VW 1.4L TSI
VW engine will be the first 4-cylinder in the industry to use cylinder deactivation tech

With more stringent fuel economy standards looming in the U.S. and elsewhere, auto manufacturers are looking to pull out all the stops to improve economy as much as possible. Carmakers are turning to technology like direct injection and automatic start/stop. Several automakers are also using cylinder deactivation on their larger engines.

Cylinder deactivation is something that some carmakers in the U.S. and abroad have used for years. Chrysler has used the technology in its Hemi engines, Honda uses it on some of its V6 models, and Audi will use cylinder deactivation in its new line of “S” performance models.

VW is set to make a first in the automotive market by offering cylinder deactivation on its 4-cylinder models.

The VW tech will turn off two engine cylinders under certain conditions. The engine is called the 1.4L TSI and VW promises that it will offer a fuel savings of 0.4-liters/100km and when combined with start/stop technology the vehicle would save 0.6-liters of fuel. For those more familiar with U.S. mpg ratings, that works out to an improvement of in the range of 
3 to 4.5 mpg on average. 

The engine would turn off two of the cylinders under low to medium loads, and VW says that the tech will meet the future European EU6 emissions standards. The cylinders will be deactivated when the engine is operating between 1,400 and 4,000 rpm and the engine torque is in the range of 25 to 75Nm.

VW claims that operating range applies to about 70 percent of the driving distance in the EU fuel economy driving cycle. VW also points out that as soon as the driver presses the pedal the cylinders will reactivate without the driver being able to tell it happened. The cylinders also would not turn off if the vehicle were being driven in a sporty manner apparently. 



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Good on paper..
By nocturne_81 on 9/6/2011 4:00:59 PM , Rating: 2
quote:
The cylinders will be deactivated when the engine is operating between 1,400 and 4,000 rpm


It may just be me, but who regularly drives past 4000 rpm unless racing or speeding..?

It all sounds great on paper, but the real world practice will be the real test. Personally, I don't know why they don't go back to the 70s-80s concept of a light car with a 70hp engine that was just capable of reaching highway speeds. My girlfriend years back had an '88 Plymouth Sundance that got 40+ mpg, even with an intake manifold leak losing loads of vacuum.. Unless it's a sports car or truck, there's no reason for a vehicle to have much more than 100hp -- and otherwise only lends to a close friend's thought that his Mazda 6 is a super-car..




RE: Good on paper..
By FITCamaro on 9/6/2011 4:09:23 PM , Rating: 3
quote:
In my opinion, unless it's a sports car or truck, there's no reason for a vehicle to have much more than 100hp


I for one like to have a vehicle that can get to 60 mph in under 15 seconds. I don't want a car that is BARELY capable of highway speeds.


RE: Good on paper..
By YashBudini on 9/6/2011 10:01:14 PM , Rating: 3
15 seconds may have been adequate in the days people saw cars attempting to merge onto the highway and actually moved over a lane to allow access. Now that rudeness and texting are the norm you risk your safety with anything that reaches 0-60 in more than 12 seconds.

quote:
there's no reason for a vehicle to have much more than 100hp

Underpowered cars suffer both performance and mileage hits. A prime example would be the Chevette, which excelled at underperforming at everything. The proper HP and gearing obtain optimal results.


RE: Good on paper..
By Calin on 9/7/2011 3:12:35 AM , Rating: 2
Look at the fuel economy for a car with smaller-to-larger engines. As the engine size increases, so does the fuel consumption.
If you drive carefully, you can get just a little bit worse mileage with a bigger engine, and have excess power when needed (passing at highway speeds, or maybe city driving accelerating away from a previously unseen danger, or rushing your way from a yield, or something).
So, underpowered cars don't suffer from mileage hits, but suffer from performance issues. Ideal would be a small engine and the capacity for quite large power surges, even if small in duration (50 HP sustained, with surges of 120+HP for 10 seconds or so). That would give you enough sprinting capacity to pass at highway speeds.
This VW engine gives instead the 40-50 or so HP in two cylinders mode and anything from some 80 to 100 HP in four cylinders mode.


RE: Good on paper..
By 0ldman on 9/7/2011 11:47:51 AM , Rating: 2
Obviously you've never owned an underpowered car. 1974 Mercury Comet with a weak 200. Pathetic power, poor mileage...

Older models did well, this one did not.


RE: Good on paper..
By Spuke on 9/7/11, Rating: -1
RE: Good on paper..
By Dorkyman on 9/7/2011 12:26:46 PM , Rating: 3
You miss the point.

A powerful engine at part throttle (high manifold vacuum) is a giant vacuum pump and very inefficient. What these designs try to do is to instantly reduce engine size so the throttle is more open, reducing manifold vacuum and increasing efficiency. Whether this switchover can be done in a way transparent to the driver is the big question, in my view.


RE: Good on paper..
By Spuke on 9/7/2011 1:02:58 PM , Rating: 2
Since this is already being done in other cars, a simple test drive should answer this question. BTW, the poster that I responded to did not mention pumping losses in his post so there was no reason for me to assume he had a clue as to what he was talking about. I didn't miss a thing. If anything, I brought a better explanation out with your post.

That said, I think you mean large displacement engine not powerful engine?? How are pumping losses greater with more hp as opposed to more displacement. I could see displacement being a factor but power? Also, how does this effect fuel efficiency? Ford's V6 gets 29 mpg, my "old" 04 Sentra 2.5L got 27 mpg (both EPA hwy 6 speed manuals). Since the Ford V6 has "more power" and hence more pumping losses, shouldn't it's fuel efficiency be worse than my old Sentra?


RE: Good on paper..
By Noya on 9/7/11, Rating: 0
RE: Good on paper..
By Calin on 9/7/2011 3:30:16 AM , Rating: 2
quote:
you gotta have something that can accelerate with aplomb

At least for a little while (and this capacity to accelerate quickly helps in city traffic too)


RE: Good on paper..
By Samus on 9/8/2011 1:29:25 AM , Rating: 2
My 2002 Focus already has this. It runs on three cylinders when it overheats, and alternates its firing order to not run one cylinder for each rotation, using it as an air pump to cool the engine.

There isn't even any added vibration as the non-firing order rotates back and fourth. There is a noticable power loss, but thats probably a combination of things the computer is doing to cool the engine down (a/f ratio, advance intake timing, retard spark)

Many ECU tunes for the SVT Focus offer an economy mode that enabled this technology for road trips, etc. People have logged hundreds of thousands of miles using it without problems.

However, the SVTF engines have various other technologies not in most engines, such as bottom feed oil squirters to cool pistons, an oil cooler, and a dual-feed oil pump that allows proper lubrication of non-firing cylinders.

So basically VW has copies Cosworth once again, but changed the technology ever so slightly :)


RE: Good on paper..
By KIJ on 9/7/2011 4:40:37 PM , Rating: 2
Had a VW with the 1.4L TSI engine. 160 HP took it from 0 - 60 mph in 8 seconds, and top-speed was just short of 140 mph... - quite okay I think...


RE: Good on paper..
By Spuke on 9/6/11, Rating: 0
RE: Good on paper..
By jang_clangle on 9/6/2011 5:25:44 PM , Rating: 4
quote:
Unless it's a sports car or truck, there's no reason for a vehicle to have much more than 100hp


And 640 kb ought to be enough for anyone, right?


RE: Good on paper..
By lagomorpha on 9/6/2011 6:10:12 PM , Rating: 2
quote:
It may just be me, but who regularly drives past 4000 rpm unless racing or speeding..?


The engine will run on 2 cylinders ONLY if between 1,400 and 4,000rpm AND the load conditions are satisfied. If you're trying to accelerate then the engine will use all 4 cylinders even if under 4,000rpm. There isn't just a sudden power surge at 4,000 when the other two cylinders come online.


RE: Good on paper..
By StevoLincolnite on 9/7/2011 6:16:34 AM , Rating: 3
quote:
The engine will run on 2 cylinders ONLY if between 1,400 and 4,000rpm AND the load conditions are satisfied. If you're trying to accelerate then the engine will use all 4 cylinders even if under 4,000rpm. There isn't just a sudden power surge at 4,000 when the other two cylinders come online.


It almost reminds me of power gating on a CPU. Shut off the extra cores when not needed to conserve power.

IMHO if it's seamless and not noticeable by users, then it should be in every car.


RE: Good on paper..
By lagomorpha on 9/7/2011 6:06:43 PM , Rating: 2
More or less, it's a little more complicated in engines.

When you deactivate cylinders in an engine, the deactivated pistons continue to move up and down in their cylinders because there's no realistic way to segment the crankshaft. Because the pistons continue to move, air continues to be pumped in and out of the cylinder. Some of the cylinder deactivation schemes close all the vales to deactivated cylinders so that they expend less energy (like operating a spring; along half the travel you get most of the energy back).

So you aren't completely shutting down the cylinders, but where you do gain efficiency is because the remaining cylinders are run on higher load. Brake specific fuel consumption is lowest at highest load at lower rpm. This means a less powerful engine will generally use less fuel per work done than a larger engine at lower load... sometimes.


RE: Good on paper..
By nocturne_81 on 9/6/2011 6:41:22 PM , Rating: 2
I guess I should have said 'not much' instead of 'no'... And the quip about rpm's was more or less meant as a statement that while driving normally, 1400-4000 is the entire range of 'cruise' driving.

Personally, I drive an old Buick LeSabre with a v6 3800 block as my daily driver, and an '82 Trans Am with an emissions-free 383 stroker v8 -- so I obviously don't care much about efficiency while driving.

To those that do indeed care, though.. Why are compact cars marketed as more sporty than efficient? Why not put your money where your mouth is and drive a teeny little 'smart' car with horrible performance?

I'm just trying to make a simple observation that it is incredibly possible to create a small 3-4 cylinder diesel engine vehicle that can achieve over 70+ mpg and satisfy the needs of most drivers -- it's just nobody would want to drive it..


RE: Good on paper..
By Johnmcl7 on 9/6/2011 7:23:12 PM , Rating: 2
It's not just possible, those engines exist over here as an option for plenty of small cars. However diesel engines don't tend to work so well in small capacities and the additional cost against money saved in fuel effiency doesn't tend to be very good for small cars with small economic petrol engines. They certainly do not satisfy the needs of most drivers, like the small Smart car engines they're ok for driving within in a city but hopeless outwith as their 15+ seconds to 60 makes them painfully slow and they struggle to keep up with other traffic.

In the UK because the tax on fuel is very high and the road tax is based on emissions (which generally favours fuel efficient cars) most cars are chosen on their fuel effiency.


RE: Good on paper..
By Shining Arcanine on 9/7/2011 12:46:54 AM , Rating: 2
People keep saying that, but I do not think that they realize that the gallons in the UK are bigger than the ones in the US. When people in the US talk about 70mpg cars, they are talking what would be 84mpg cars in the UK, which I do not believe exist anywhere right now.


RE: Good on paper..
By Keeir on 9/7/2011 6:35:51 PM , Rating: 2
Its also important to note the different Fuel Efficieny Measurements.

Based on Toyota and VW comparison points,

A 70 US EPA rating = 95-100 UK EU Rating


RE: Good on paper..
By Jeffk464 on 9/7/2011 7:10:42 PM , Rating: 2
You also don't worry about driving decent cars it seems.


RE: Good on paper..
By mindless1 on 9/6/2011 8:54:07 PM , Rating: 2
Why not?

1) Safety features raise vehicle weight too much.

2) Emissions standards have gone up.

3) It's less profitable for manufacturers to make automobiles that, given today's material and manufacturing improvements, wouldn't break so often anymore and would be inexpensive to fix if the complexity weren't increased.

4) They don't do it because despite those vocal about "everyone else should drive shi!tcans to save gas", most people DO NOT WANT THESE ANEMIC CARS, they prefer a trade-off between fuel efficiency and other factors.

5) "Just capable of reaching highway speeds" would assume that other people are going to get out of your way when you are merging onto the highway, which is reckless driving. To safely drive you need a margin, an amount of acceleration beyond what you use regularly to deal with situations where there isn't a gap in traffic without speeding up or slowing down to fit into it and slowing down is NOT the better option merging into traffic going 60MPH+.

6) There's no good reason for a vehicle NOT to have 100HP+, with today's engine tech there is minimal weight added relative to total vehicle weight, and increases in efficiency per lb of motor weight, plus with the higher vehicle weight:size you need something capable of a little more torque.

In other words, if today's version of an '88 Sundance were made, the car would weigh more from safety *improvements* and get no better mileage tuned to today's emissions standards than what you can already buy, and would be less comfortable and handle worse. Also, while your GF might have had good luck, in general I don't recall small '88 Plymouths being particularly reliable vehicles... but at least you could buy them dirt cheap once they were used, small American cars at least had THAT going for them.


RE: Good on paper..
By YashBudini on 9/6/2011 10:23:06 PM , Rating: 2
quote:
3) It's less profitable for manufacturers to make automobiles that, given today's material and manufacturing improvements, wouldn't break so often anymore and would be inexpensive to fix if the complexity weren't increased.

Uh excuse me, but the average lifespan of a tie rod on a Chrysler 300 is about 30K miles. (Ask your local dealer if you doubt this.) Complexity isn't the problem here, so why does it break so often? Your should understand why when the dealer tells you "30K miles is normal."

It's not the complexity that makes many cars unreliable, it's the attitude.

And no, it's not normal, not for a high quality car.


RE: Good on paper..
By lagomorpha on 9/6/2011 11:11:10 PM , Rating: 2
"Complexity isn't the problem here, so why does it break so often?"

Because only morons buy Chryslers so Chrysler can get away with making its cars junk heaps. Anyone that knew better wouldn't buy a Dodge/Chrysler in the first place.


RE: Good on paper..
By FreeTard on 9/9/2011 3:46:46 AM , Rating: 2
You get 30k miles on your tierod??? I'm jealous I've got an 08 Wrangler. I get 9k on my ball joints, wheel bearings at 15k, and a differential that sucks in water at every puddle. Oh, let's not forget the MINIVAN engine on a vehicle shaped like a brick. Oh yeah and the transmission that runs too hot from the factory, with no sensor to warn you that you're overheating... you only find out after you've caught fire. Or the transmission cooler that was designed to leak oil. I could go on all day about how much I'd love to punch a Chrysler engineer in the balls.

I only bought the Jeep because it was a Jeep and because I can replace every part of it with a 3rd party. The only decent factory part is the frame... but I'm sure it sucks too. I wish they had sold it to Toyota. I curse those Chrysler pricks every time I work on the heap. Who in their right mind would decide to put 17mm bolts on one shock, and 7/8ths bolts on the other (on the rear). Who in their right mind would decide that a 16mm bolt is close enough to a 9/16th bolt hole on the track bar and control arms, thus destroying the bolt holes? Oh, a Chrysler engineer would.

10,000 parts all from the lowest bidder.


RE: Good on paper..
By Spuke on 9/7/2011 12:07:42 AM , Rating: 2
quote:
Your should understand why when the dealer tells you "30K miles is normal."
I know not everyone is a mechanic and we depend on these people to fix our cars BUT, I wouldn't take his word on it. And I sure as hell wouldn't buy a Chrysler.


RE: Good on paper..
By YashBudini on 9/7/2011 12:56:13 AM , Rating: 2
All I was inferring to is that the "service person" would find such terrible reliability to be normal. That they actually believe that? Yes, I think they do.


RE: Good on paper..
By Spuke on 9/7/2011 11:49:40 AM , Rating: 2
quote:
That they actually believe that? Yes, I think they do.
I agree. Shame, huh?


RE: Good on paper..
By lagomorpha on 9/7/2011 6:09:24 PM , Rating: 2
A "service person" mostly sees cars that people bring to them to repair. If a component didn't break then the "service person" wouldn't see it often. At this point most know better than to buy Chryslers.


RE: Good on paper..
By mindless1 on 9/7/2011 4:43:57 AM , Rating: 2
Didn't you sort of align with what I wrote? That even after all these years of supposed refinements they find a more complex way (versus reuse of existing tie rod design with reasonable part lifespan) to make one more failure prone?

On the other hand, if you take the same sized car and weigh it down with (more complexity) safety improving features, you're putting more stress on the suspension, steering, etc.

All cars have their weak links though, and to some extent the weakest one is owners who drive like a bat out of hell thanks to their car having a peppy engine.


RE: Good on paper..
By YashBudini on 9/6/2011 10:15:04 PM , Rating: 2
quote:
It may just be me, but who regularly drives past 4000 rpm unless racing or speeding..?

This only addresses intentional driving and not a need to accelerate quickly in an emergency to avoid a collision.

quote:
with a 70hp engine that was just capable of reaching highway speeds.

Picture if you purchased tires with this logic, only barely adequate for running around. You buy tires better than this yes for fun but also for a larger safety margin. And extra HP can translate into a type of safety margin. If you have any doubts just ask a motorcycle rider.


RE: Good on paper..
By Manch on 9/7/2011 4:49:09 AM , Rating: 2
quote:
My girlfriend years back had an '88 Plymouth Sundance that got 40+ mpg, even with an intake manifold leak losing loads of vacuum..


umm...a leaking intake manifold would make fuel economy worse and that cars combined mpg for the time was only 25mpg. By todays standard that would probably be 21-22 if the car was in top shape.

http://mpgfacts.com/?year=1988&make=&class=&start=...

131 COMPACT CARS PLYMOUTH SUNDANCE 4 2.2 L M5 22 30 25


RE: Good on paper..
By nocturne_81 on 9/7/2011 5:31:08 PM , Rating: 2
I may have exaggerated a bit, but it got at least somewhere in the upper 30s... Don't ask me how, but the lil car was a trooper... Bought for $350 with 90k miles, drove for 5 yrs, then sold it for $500 with 130k miles (sold it rather than fix it.. the buyer then drove it another 2 yrs with the manifold leak before selling it to someone else..). Could drive from here to cleveland (1 hr), then to columbus (2hrs), and then back home on a single tank of gas with a bit to spare. In our harsh NE Ohio winters, it never got stuck -- never. Seemed like it was so light it just floated on top of the snow, where I'd get stuck pulling out right after..

That was then, though.. I could never in good conscience recommend a Chrysler now. It's like Chevy's switch from the cavalier to the cobalt. Shoddy as the cavalier was, any that ever drove both can certainly admit that the cobalt drives like a tin can on wheels.


RE: Good on paper..
By Jeff7181 on 9/7/2011 10:17:25 AM , Rating: 2
quote:
Personally, I don't know why they don't go back to the 70s-80s concept of a light car with a 70hp engine that was just capable of reaching highway speeds.


Because it's dangerous. Try to merge onto a busy highway when it takes 15 seconds to go from 40 to 70 mph.


RE: Good on paper..
By bjacobson on 9/7/2011 6:07:22 PM , Rating: 2
quote:
Unless it's a sports car or truck, there's no reason for a vehicle to have much more than 100hp


hey why don't we replace all our sugar with saccharine while we're at it? Then what's next? Hate week?


RE: Good on paper..
By bigdawg1988 on 9/8/2011 11:28:57 AM , Rating: 2
Unless it's a sports car or truck, there's no reason for a vehicle to have much more than 100hp

Yeah, try driving in a city like Atlanta with a car like that and you might get pulled over for holding up traffic... if they don't kill you first!


RE: Good on paper..
By mindless1 on 9/8/2011 11:54:26 PM , Rating: 2
Who regularly gets their engines past 4000 RPM without racing or speeding? All those econonuts who buy cars with anemic engines but don't want to be azzhatz holding up traffic.

It's really easy to get an economy car past 4000 RPM and be driving no faster than someone else does at far lower RPM.


Really!?
By Dr of crap on 9/6/11, Rating: 0
RE: Really!?
By Smartless on 9/6/2011 3:29:58 PM , Rating: 2
I think 5mpg is a rather good amount of fuel savings. As for small increases for big money, look at most hybrids.

Biofuels are great and all but its going to take a few more years of research, process refining, infrastructure placement and probably some minor tweaking of a vehicle (excluding bio-diesel) to get it out. It's kinda hard to justify that kind of capital expense and then charge beans for it.

Heck if we're going to look that far ahead at bio-fuels, look further and see if we can get fuel cells moving. In Hawaii, private PV is all the rage. I've seen systems that charge fuel cells through solar. Won't work for the whole nation but hey we don't got the land or money to try everything else.


RE: Really!?
By seamonkey79 on 9/6/2011 4:16:06 PM , Rating: 2
On even a 30mpg vehicle, 5mpg is a 17% increase in economy, which isn't all that bad.


RE: Really!?
By zorxd on 9/6/2011 7:22:52 PM , Rating: 2
Almost, but you got it wrong, mainly because of the units you are using.

30 miles per gallon = 7.84048611 L/100km
35 miles per gallon = 6.72041667 L/100km

1 - 6.72041667 / 7.84048611 = 0.142857142

Therefore, it's a 14% (not 17%) decrease in fuel consumption. There is no such thing as car "fuel economy". A car doesn't economize fuel, it consumes fuel.


RE: Really!?
By Black1969ta on 9/7/2011 8:48:18 AM , Rating: 2
quote:
Therefore, it's a 14% (not 17%) decrease in fuel consumption. There is no such thing as car "fuel economy". A car doesn't economize fuel, it consumes fuel.


While that whole statement is half true it is also completely wrong.
While it is true that a car does consume fuel some do it more economically than others(Hummer Vs. Prius) so a car's fuel economy is a measure of consumption, standardized in such a way to make it comparable between vastly different models.

and...

30 mpg to 35 mpg is 5 mpg increase
is 5/30=0.1666666666...
so, 17% increase in fuel economy, like he said.


RE: Really!?
By MonkeyPaw on 9/6/2011 6:33:34 PM , Rating: 2
My concern is reliability. I know some folks who own VWs, and they have issues already. Granted, it's the notorious Beetle, but....


RE: Really!?
By Spuke on 9/7/2011 12:10:45 AM , Rating: 2
quote:
My concern is reliability. I know some folks who own VWs, and they have issues already. Granted, it's the notorious Beetle, but....
The only marque lower than VW is Kia on JD Powers long term reliability. Is JD 100%? Who knows. But I doubt they would be that much higher.


RE: Really!?
By lagomorpha on 9/8/2011 8:45:23 AM , Rating: 2
http://autodoll.info/jd-powers-2011-vehicle-reliab...

You forgot about Chrysler/Dodge/Jeep, Land Rover and Mini.

The JD Power survey only took the number of problems per 100 vehicles. It could be a burnt out window motor or a blown engine and it was counted the same. German cars, especially VW, do have the reputation of having electrical components that will break constantly but engines and transmissions that will be working for decades. Then there's the issue that Beetles were made in Mexico and showed much less reliability than VWs made in Wolfsburg or Pennsylvania.


RE: Really!?
By YashBudini on 9/8/2011 9:24:32 PM , Rating: 2
Looking at the graphs, which don't expand shame on you JDP, we see BMW and Mini made by BMW far down the list. For what they charge there's simply no excuse.


RE: Really!?
By MrTeal on 9/6/2011 4:44:09 PM , Rating: 5
Right, so engine deactivation which is already used in many vehicles with little increase in cost is going to be a huge cost increase for VW, but biofuels are a way cheaper alternative.

Is that a corn cob in your pocket, or are you just happy to see everyone?


RE: Really!?
By barturtle on 9/6/2011 4:54:00 PM , Rating: 2
Actually with modern engine control systems, this can be achieved with a bit of programming and engineering time. Quite inexpensive to accomplish.

At low load operation (cruise on on flat terrain) and 1400 rpm it should be as smooth as at low idle.

Looking at the image, they have 1-4 and 2-3 paired, so if you shut off 1-4 and leave 2-3 running you'll have even firing cycles on those two cylinders, and the same if you shut off 2-3 and leave 1-4 running. There would normally be a preference to shut off 2-3 and leave 1-4, as 1-4 are supported by completely separate main bearings, while 2-3 share one in common.


RE: Really!?
By YashBudini on 9/6/2011 10:47:05 PM , Rating: 2
quote:
Quite inexpensive to accomplish.

In 2011 the GTI Turbo accomplished traction control by applying brake pressure to individual wheels via computer control. Inexpensive to implement, but that's not the only cost for us.

German hardware has never had the kind of reliability in league with their reputation. Factor in what we'll see of this will be made in Mexico and it will be "Version 1.0" and you should ask yourself if you really want to rush into this.

Why kind of real life savings is Honda's V6 seeing with this technology?


the reason you have not seen this
By tastyratz on 9/6/2011 2:25:33 PM , Rating: 2
I love the idea, I think it has been a long time coming, and I hope it works well. The problem with deactivation on a 4 cyl is that you get increased nvh going down to just a few cylinders. You will see a much rougher running engine.

Is this a specific or dynamic deactivation? If it were to say deactivate 1+2 on one cycle then 3+4 on the next you might see more even engine wear but have a much harder time getting a tune to run right.

I think I would be more receptive to a far more sophisticated, enlarged, and metered egr system. Exhaust gas is inert and if you fill a 0.5 liter engine with .25 liters of exhaust gas you have achieved a 50% deactivation by practice. On a 4 cyl 4 small charges will be much smoother.

I would like something where maybe the charge is piped through a cooler and then delivered individually to each cylinder. Maybe even compressed and metered by means of air injectors? Wasn't Ford or someone else working on some sort of similar technology recently?




RE: the reason you have not seen this
By Argon18 on 9/6/2011 3:08:26 PM , Rating: 3
IMO this all goes back to a fundamental shortcoming of the gasoline engine; that for a given amount of air in the cylinders, a certain percentage of fuel MUST be injected. Gasoline engines cannot run much leaner than 16:1 without overheating.

Diesel engines on the other hand can run as lean as 80:1 air to fuel ratio, which is part of the reason they are far more fuel efficient than gasoline engines. It's also the reason that a modern diesel engine uses almost no fuel at all while idling - as the computer knows to lean the mixture out to the maximum leanness. Also, while gasoline engines run hotter the leaner the mixture is, diesel engines run *cooler* the leaner the mixture is. So when they're sitting there idling, not only are the conserving fuel, they're also virtually immune to overheating.


By Spuke on 9/6/2011 5:09:22 PM , Rating: 3
quote:
Gasoline engines cannot run much leaner than 16:1 without overheating.
Nope. Direct injected engines can run as lean as 40:1 and even 65:1 or more.


RE: the reason you have not seen this
By lagomorpha on 9/6/2011 6:16:22 PM , Rating: 2
You're comparing constant pressure engines to constant volume engines.

In a diesel engine, the air intake is left fully open and the throttle controls how much fuel is injected into the cylinder. Press on the gas pedal = more fuel.

In a gasoline engine, the gas pedal controls a butterfly valve in the intake which lets more air in then either a carb or fuel injection will do its best to keep to the designed air-fuel ratio. (14.7:1 stoichiometric though modern EFI will run leaner under certain conditions for emissions reasons and old British motorcycles ran rich to aid with cooling and no one cared that they got bad gas mileage).

It isn't a matter of the computer leaning out the diesel when it's idling, the throttle position directly means less fuel is being injected.


RE: the reason you have not seen this
By haplo602 on 9/7/2011 2:41:59 AM , Rating: 2
modern cars have without exception electronic gas pedals. means the computer ALWAYS controls how much fuel is injected.


By mindless1 on 9/8/2011 11:49:52 PM , Rating: 2
They don't have to be so modern either, nor have electronic gas pedals. When the first, maybe 2nd generation of fuel injected vehicles arrived over 20 years ago, you still had a throttle cable from the gas pedal but it went to a throttle plate which just opened more to let more air in, then the mass airflow and temperature sensors fed the ECM (computer) this data upon which it determined fuel injection time = rate/volume.


By Calin on 9/7/2011 3:26:44 AM , Rating: 2
The FSI technology (fuel stratified injection) for gasoline engines allows to use only a part of the cylinder volume for burning fuel (the rest of the cylinder space is air). This helps reduce the fuel needed at idle (and increases the apparent fuel-to-air ratio for the entire cylinder volume)


By tastyratz on 9/7/2011 12:12:42 PM , Rating: 2
direct injection has alleviated much of the lean burn issues at light throttle but yes, you still need a certain amount. That's why I was thinking egr. if you need 1 cc of fuel for example with no egr system at all, the egr could fill 50% of the chamber and you would only need 0.5cc of fuel to achieve the same exact ratio as before. This of course is all in theory and I don't know what other issues one might run into trying to implement a system like this


Other ways to improve mileage.
By YashBudini on 9/6/2011 10:31:02 PM , Rating: 2
1. Remove the 306HP V6 from the 31mpg Mustang.

2. Transplant the engine and transmission into a Mazda Miata. Retain the long legged gearing.

Many people put V8s in them, I find this a tad excessive.




RE: Other ways to improve mileage.
By Spuke on 9/7/2011 12:15:55 AM , Rating: 2
That would be a fun car.


Nice hands off approach.
By quiksilvr on 9/6/2011 1:15:32 PM , Rating: 2
This reminds me of the nVidia Optimus technology that automatically detects if it needs the dedicated graphics and turns it on and off automatically. Some laptops like the Vaio had a switch but I feel this automatic approach is best.




4cylinder engine development...
By meef on 9/10/2011 5:31:58 AM , Rating: 2
Seems these car manufacturers could save a MINT if they just partnered with a motorcycle manufacturer. Honda is in the best position with the small engines as they sell motorcycles and cars. It seems the other manufacturers could partner with yamaha, kawi, suzuki and get some great engines on the cheap.

coolest thing is what they did in England, building a lower engine with 2 motorcycle engine cylinders making a v8 out of 2 motorcycle engines. I think they offer an ariel atom with that motor now.




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