Radical Engine Redesign Would Reduce Pollution, Oil Consumption

[one...two...tree 2,762]

Researchers have created the first computational model to track engine performance from one combustion cycle to the next for a new type of engine that could dramatically reduce oil consumption and the emission of global-warming pollutants.

"We're talking about a major leap in engine technology that could be used in hybrid cars to make vehicles much more environmentally friendly and fuel stingy," said Gregory M. Shaver, an assistant professor of mechanical engineering at Purdue University.

A key portion of his research, based at Purdue's Ray W. Herrick Laboratories, hinges on designing engines so that their intake and exhaust valves are no longer driven by mechanisms connected to the pistons. The innovation would be a departure from the way automotive engines have worked since they were commercialized more than a century ago.

In today's internal combustion engines, the pistons turn a crankshaft, which is linked to a camshaft that opens and closes the valves, directing the flow of air and exhaust into and out of the cylinders. The new method would eliminate the mechanism linking the crankshaft to the camshaft, providing an independent control system for the valves.

Because the valves' timing would no longer be restricted by the pistons' movement, they could be more finely tuned to allow more efficient combustion of diesel, gasoline and alternative fuels, such as ethanol and biodiesel, Shaver said.

The concept, known as variable valve actuation, would enable significant improvements in conventional gasoline and diesel engines used in cars and trucks and for applications such as generators, he said. The technique also enables the introduction of an advanced method called homogeneous charge compression ignition, or HCCI, which would allow the United States to drastically reduce its dependence on foreign oil and the production of harmful exhaust emissions.

The homogeneous charge compression ignition technique would make it possible to improve the efficiency of gasoline engines by 15 percent to 20 percent, making them as efficient as diesel engines while nearly eliminating smog-generating nitrogen oxides, Shaver said.

This improved combustion efficiency also would reduce emission of two other harmful gases contained in exhaust: global-warming carbon dioxide and unburned hydrocarbons. The method allows for the more precise control of the fuel-air mixture and combustion inside each cylinder, eliminating "fuel rich" pockets seen in conventional diesel engines, resulting in little or no emission of pollutants called particulates, a common environmental drawback of diesels.

The variable valve actuation system makes it possible to "reinduct," or reroute a portion of the exhaust back into the cylinders to improve combustion efficiency and reduce emissions. The system also makes it possible to alter the amount of compression in the cylinders of both conventional and HCCI engines and to adjust the mixing and combustion timing, allowing for more efficient combustion.

"Variable valve actuation and HCCI would help to significantly reduce our dependence on oil by enabling engines to work better with ethanol and biodiesel and other alternative fuels," Shaver said. "But accomplishing this is going to require a strong effort in several research areas - a commitment of funding, people power, industrial involvement and academic involvement."

http://www.sciencedaily.com/releases/2007/...70510093248.htm

[mawilson 2,133]

So what's the hp and torque on this new engine?

[one...two...tree 2,762]

So what's the hp and torque on this new engine?

It's not a specific engine but a different way of designing the combustible engine. Variable valve timing engines have been around for awhile (Honda, Toyota), and if anything, increase an engine's horsepower.

[Trumplestiltskin 5,791]

I was listening to NPR last night and what is interesting is that fuel economy has actually increased a lot during the last 20 years, but all that extra efficiency has been channelled into putting extra power in the engine.

In the 80's the average acceleration from 0-60 was 14 seconds, today its 9.

[one...two...tree 2,762]

I was listening to NPR last night and what is interesting is that fuel economy has actually increased a lot during the last 20 years, but all that extra efficiency has been channelled into putting extra power in the engine.

In the 80's the average acceleration from 0-60 was 14 seconds, today its 9.

Which demonstrates that the market alone will not steer automakers to make higher fuel efficient cars.

[mawilson 2,133]

I was listening to NPR last night and what is interesting is that fuel economy has actually increased a lot during the last 20 years, but all that extra efficiency has been channelled into putting extra power in the engine.

In the 80's the average acceleration from 0-60 was 14 seconds, today its 9.

I've noticed that as well.

[Trumplestiltskin 5,791]

I was listening to NPR last night and what is interesting is that fuel economy has actually increased a lot during the last 20 years, but all that extra efficiency has been channelled into putting extra power in the engine.

In the 80's the average acceleration from 0-60 was 14 seconds, today its 9.

Which demonstrates that the market alone will not steer automakers to make higher fuel efficient cars.

Well the engine is more efficient - just that the saved fuel economy is being used to increase horsepower and acceleration. If they took out that extra acceleration you'd have a generally more efficient engine than you would have had 20 years ago.

[one...two...tree 2,762]

I was listening to NPR last night and what is interesting is that fuel economy has actually increased a lot during the last 20 years, but all that extra efficiency has been channelled into putting extra power in the engine.

In the 80's the average acceleration from 0-60 was 14 seconds, today its 9.

Which demonstrates that the market alone will not steer automakers to make higher fuel efficient cars.

Well the engine is more efficient - just that the saved fuel economy is being used to increase horsepower and acceleration. If they took out that extra acceleration you'd have a generally more efficient engine than you would have had 20 years ago.

The fuel mileage saga is spelled out in the MPG Super Stars chart. Five 1992-vintage cars outperform the best gasoline-powered offerings from 2007 while a sixth equals them in highway mileage.

The Geo Metro XFI and Honda Civic VX produce hybrid-challenging numbers. The Metro tops the chart at 53 city, 58 highway while the Civic VX is right on its heels at 48 city, 55 highway. Both Metro XFI and the Metro LSi (also offered as the Chevrolet Sprint in 1992) are small, lightweight vehicles motivated by a 1.0-liter, three-cylinder powerplant.

There is no doubt that these GM hatchbacks lack the creature comforts and build quality of modern econoboxes and at 49 horsepower, they are not inspiring performers. Conversely, the Civic VX was a new, fresh-sheet car in 1992 with highly rated ergonomics, excellent build quality and more than twice the pep of the XFI at 102 horsepower. Despite their shortcomings for the environmentally conscious, these misers are indeed super stars.

MPG Super Stars [city/hwy]

.............1992 ....................................... 2007

Geo Metro XFI ('93) 53 / 58 Toyota Yaris 34 / 40

Honda Civic VX 48 / 55 ..........MINI Cooper 32 / 40

Geo Metro LSI 46 / 50

Suzuki Swift 39 / 43

Ford Festiva 35 / 42

Dodge Colt ('93) 32 / 40

Under the banner of, "the more things change the more they stay the same," we present the Super Suckers. The worst fuel mileage vehicles on the road have evolved little in the last decade and a half. The Lamborghini Diablo of 1993 and the present day Lamborghini Murcielago both have V12 power and the same woeful 9 city, 14 highway performance.

The Vector W8 was a low-volume specialty car that did not stay in the market very long but it did take the title of least fuel efficient. Granted buyers of these rides care little about their daily fuel consumption and these supercars are not driven all that much but you would expect Lamborghini could at least nudge the needle in right direction 15 years later.

The meatiest comparisons focus on the same make and model of car in 1992 and 15 years later in 2007. The most shocking of the apples-to-apples showdowns is the Honda Civic. In the last 15 years the Civic has given up ground in a big, nearly unimaginable way; dropping 12 MPG city and 8 MPG highway. How is this possible? The four-cylinder engine has grown from 1.5-liters in '92 to 1.8-liters in 2007. But come on, engine displacement is not the issue, overall displacement, read curb weight, is.

Just as Americans have embraced obesity, the lowly Civic has gone from 2094 pounds in 1992 CX hatchback trim to 2751 pounds in 2007 sedan trim; the additional 657 pounds of girth in the '07 version will certainly make efficiency numbers plummet. Calculating a sedan versus sedan comparison reveals the 1992 edition to be 432 pounds lighter on the scales.

It should be noted that there were a wide variety of Civics offered in '92. In addition to the aforementioned VX, seven other Civic models delivered between 27 and 42 mpg in the city and 34 and 48 mpg on the highway.

http://editorial.autos.msn.com/article.asp...cumentid=435714

[Saddle Bronc 124]

Steven, there's also been another way of simplifying (and increasing hp and torque of) a piston-petrol or diesel engine--basically two-stroke. Allows use of a smaller-displacement engine to achieve the same hp/torque (fuel consumption for same displacement goes up, reduction in size has some salutary effect).

Edited December 20, 2007 by CherryXS

[Ban Hammer 13,346]

The Geo Metro XFI and Honda Civic VX produce hybrid-challenging numbers. The Metro tops the chart at 53 city, 58 highway while the Civic VX is right on its heels at 48 city, 55 highway. Both Metro XFI and the Metro LSi (also offered as the Chevrolet Sprint in 1992) are small, lightweight vehicles motivated by a 1.0-liter, three-cylinder powerplant.

had a metro back in the early 90's - pretty good little car. the button to turn on the ac we called the "turbo" button as you could turn off the ac with it and get extra power

[lucyrich 20]

The fuel mileage saga is spelled out in the MPG Super Stars chart. Five 1992-vintage cars outperform the best gasoline-powered offerings from 2007 while a sixth equals them in highway mileage.

The Geo Metro XFI and Honda Civic VX produce hybrid-challenging numbers. The Metro tops the chart at 53 city, 58 highway while the Civic VX is right on its heels at 48 city, 55 highway.

Yep, I had a '95 Civic VX, which I just sold a few months ago. It would consistently get above 50 mpg on the highway with the A/C on, and the worst it ever got in town was 38 mpg. Plenty of pep for merging and hill climbing, but not overpowered. And yes, it had variable valve timing, similar to what the original post refers to (less sophisticated, though). It was perfectly reliable, with not a single breakdown or failure to start in 13 years, and it was cheap to maintain. Of all the cars I've owned, that was the one I was most satisfied with. It had the lowest annual cost of ownership, too. If Lucy could drive a stick, we would have kept it longer. Also, being a two door with a hatch, the rear seat access wasn't great, which became a problem when the baby arrived.

It was comfortable, but everything on it was manual. Manual crank windows, manual transmission, manual mirrors, manual seats, manual door locks, etc. That probably contributed somewhat to its reliability. I'm amazed at the number of electric motors on new cars. I wonder how much of that 432 pound weight gain of the Civic has been in electric motors?

[Jaseball 0]

The metro was a death trap though, especially with all the SUV's being driven by aggressive ####### drivers like they are in the Indy 500.

This sounds like cool tech, but how much would it cost to get it into production? It does just sound like far more advanced VVT tech.

[one...two...tree 2,762]

The Geo Metro XFI and Honda Civic VX produce hybrid-challenging numbers. The Metro tops the chart at 53 city, 58 highway while the Civic VX is right on its heels at 48 city, 55 highway. Both Metro XFI and the Metro LSi (also offered as the Chevrolet Sprint in 1992) are small, lightweight vehicles motivated by a 1.0-liter, three-cylinder powerplant.

had a metro back in the early 90's - pretty good little car. the button to turn on the ac we called the "turbo" button as you could turn off the ac with it and get extra power

lol...I've done the same for most of the small 4 cylinders I've owned.

[one...two...tree 2,762]

The fuel mileage saga is spelled out in the MPG Super Stars chart. Five 1992-vintage cars outperform the best gasoline-powered offerings from 2007 while a sixth equals them in highway mileage.

The Geo Metro XFI and Honda Civic VX produce hybrid-challenging numbers. The Metro tops the chart at 53 city, 58 highway while the Civic VX is right on its heels at 48 city, 55 highway.

Yep, I had a '95 Civic VX, which I just sold a few months ago. It would consistently get above 50 mpg on the highway with the A/C on, and the worst it ever got in town was 38 mpg. Plenty of pep for merging and hill climbing, but not overpowered. And yes, it had variable valve timing, similar to what the original post refers to (less sophisticated, though). It was perfectly reliable, with not a single breakdown or failure to start in 13 years, and it was cheap to maintain. Of all the cars I've owned, that was the one I was most satisfied with. It had the lowest annual cost of ownership, too. If Lucy could drive a stick, we would have kept it longer. Also, being a two door with a hatch, the rear seat access wasn't great, which became a problem when the baby arrived.

It was comfortable, but everything on it was manual. Manual crank windows, manual transmission, manual mirrors, manual seats, manual door locks, etc. That probably contributed somewhat to its reliability. I'm amazed at the number of electric motors on new cars. I wonder how much of that 432 pound weight gain of the Civic has been in electric motors?

That's awesome! I just bought a used '93 Civic EX Coupe ...has 156k miles on it, but it's in good shape and I'm sure it's got at least another good 50k on it. I needed to find a commuter car that was easy on the gas. Do you know why they stopped making the VX? Or is it because all the newer Honda's have the V-Tec (variable valve engines)?

As far as the weight gain...what I've noticed is the increased size in the Civics. I think the latest designs are fugly. They don't look ergonomic, just bulky. I'd love to find a Civic VX that still has some life left in it.

[lucyrich 20]

Do you know why they stopped making the VX? Or is it because all the newer Honda's have the V-Tec (variable valve engines)?

As far as the weight gain...what I've noticed is the increased size in the Civics.

Yep, they keep getting bigger and gaining weight. The Honda Fit is bigger than the original Civic, and I think today's Civic is bigger than the original Accord.

I don't know why they quit making the VX. Maybe to spur demand for their hybrids. The VX had a VTEC-E engine, which isn't the same as the other VTECs. All the VTEC engines use variable timing, but for slightly different purposes. The VTEC-E was specifically designed for fuel economy. It shut off one intake valve below 2500 RPM. There was virtually no torque available below 2500 RPM. Performance was pathetic at low RPMs, but as you accellerated above 2500 RPM, you'd feel the extra valve kick in, and from 2600RPM to redline, performance was reasonably peppy and normal for a 1.6L four cylinder engine.

Gearing was set so that it would cruise at 75mph and still stay below the magic 2500 RPM for nice efficiency. If you wanted pep, you'd avoid fourth and fifth (and usually third) gears.