Article: GM's powertrain plan: Less weight, better technology

[cfg83]

Hello -

Looks like we may be seeing some interesting GM engines in the future :

GM's powertrain plan: Less weight, better technology | Car Tech: An automotive blog from CNET - CNET Reviews

DETROIT -- General Motors' heavy investments in powertrain technology are beginning to pay off in terms of better fuel economy.

GM is slowly building its hybrid business and will launch one new hybrid per quarter for the next four years. The company has just opened an advanced powertrain testing laboratory in suburban Detroit. The automaker is rolling out engine technologies that maintain performance while lowering emissions and fuel use. GM has been adding gears to automatic transmissions, reducing the weight of its powertrains and designing engines capable of being mass produced with high-tech features such as direct fuel injection and turbochargers.

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Technology: GM hopes to be the first automaker to launch a vehicle with an HCCI engine. Homogeneous charge compression ignition enables a gasoline engine to run like a diesel at idle and at cruising speeds. The result is about a 15 percent fuel economy gain and dramatically lower emissions.

HCCI also is a key technology in terms of where GM wants to take gasoline engines before they start to be replaced by electric motors.

"Downsizing (displacement) with boosting is awesome," said GM powertrain exec Stephens, referring to the Solstice and Sky 2.0-liter engines. "But combining this with HCCI is really where I want to get to."

Fuel cells are also in GM's near future. The company is launching test fleets of Chevrolet Equinox hydrogen-powered fuel cell vehicles in North America, Japan and Europe. GM's latest generation of fuel cell can fit in the space of a four-cylinder engine. The company expects to have fuel cells ready for mass production by 2012.

Transmissions: Nearly all of GM's automatics will be six-speeds.

CarloSW2

[jamesqf]

The problem with this is that they're trying to do incremental improvements to current technology, when what's needed for a quantum leap in fuel economy is a switch to a different technology. The Volt powertrain is a start.

[tjts1]

+1
All new cars should have jet engines.

[cRiPpLe_rOoStEr]

GM already has some options to improve the overal fuel-efficiency across the range. The turbocharged 2.0L Ecotec could even be applied to a Silverado 1500 or to the late Hummer H3. With the same tuning stage currently used in the Buick Verano, it has more power than the Vortec 3700 5-banger and the same torque of the Vortec 4300 V6 from lower RPM bands while retaining a broader torque curve which enhances the driveability, all in a smaller lighter package.

[gone-ot]

HCCI "still" is still-born.

[serialk11r]

Originally Posted by Old Tele man

HCCI "still" is still-born.

Just reading up on the techniques that they're trying to implement, it sounds way too complicated and expensive. Dual spark or laser ignition would already be over the top, but at least you don't need to precisely control intake temperatures, compression ratio, etc. which gets harder as the engine ages.

I feel like laser ignition at multiple points should be able to get most of the way there, if burn speed is really worth pursuing at all.

[cRiPpLe_rOoStEr]

Originally Posted by serialk11r

Just reading up on the techniques that they're trying to implement, it sounds way too complicated and expensive. Dual spark or laser ignition would already be over the top, but at least you don't need to precisely control intake temperatures, compression ratio, etc. which gets harder as the engine ages.

I feel like laser ignition at multiple points should be able to get most of the way there, if burn speed is really worth pursuing at all.

I'd rather go Diesel. As it had already been proved by Scania, and also some sugarcane farms which had independent conversions, a Diesel engine with direct injection can easily run on thinner fuels such as ethanol.

[Allch Chcar]

It's ironic reading this now. "Lighter" from the manufacturer that couldn't design and build a compact car that weighs under 3000lbs.

I don't like to disregard Diesel but US emissions make it cost prohibitive to sell them here. I know that people with pickup trucks and SUVs would buy Diesels if they could. It makes it harder and harder for manufacturers to justify designing Diesels for US emissions.

[serialk11r]

I thought diesel engines are more expensive than gasoline engines even without the expensive emissions equipment?

Spark ignition engines are really not as evil as some people would like to make them out to be, they just need a few improvements here and there which will come with time. Toyota thinks they can hit 45% peak thermal efficiency with streetworthy spark ignition engines :shrug:

[Diesel_Dave]

Originally Posted by serialk11r

I thought diesel engines are more expensive than gasoline engines even without the expensive emissions equipment?

The emissions equipment is where the real cost difference is. Consider this: About 3 years ago, Cummins developed a 5.0L V8 diesel that Dodge was going to be put in their 1/2 ton pickup. Cummins had a contract, but that got axed when Chrysler went bankrupt in '09. Anyway, Diesel Power magazine reported that the cost of just the diesel's emissions equipment was the same as the cost of the entire gasoline-based powertrain (engine, transmission, emissions equitpment, etc.).