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http://money.cnn.com/2008/05/30/autos/hcci/index.htm?source=yahoo_quote

NEW YORK (CNNMoney.com) -- Car companies are working to perfect a new generation of gasoline engines that could get up to 20% better fuel efficiency. The system, which burns gasoline without spark plugs, relies in massive amounts of speed and power - the computer kind - to work.

It's called Homogenous Charge Compression Ignition, or HCCI. General Motors (GM, Fortune 500) has been allowing journalists to drive a test vehicle with this technology. It clearly isn't quite ready for the mass market, but GM insists that it's finally in the home stretch after years of trying.

"You're basically getting the best of gas and diesel all together," said Kelly Mundt, director of gasoline system marketing for auto parts supplier Bosch, which is working on some components needed for this new engine system.

That means more fuel efficiency, like a diesel, but with cleaner exhaust. But it's not easy to get a gasoline engine to behave this way.

This technique for burning gasoline requires loads of on-board computing power and the ability to control to the tiniest degree everything that goes on inside the engine in real-time. The ideas behind HCCI have been around for decades, but the parts have only come together in the last few years.

Big differences
In normal gasoline engines, the injector squirts fuel into the cylinder as the piston rises, and at just the right moment, a spark ignites the fuel.

Diesel engines compress air inside a cylinder until it's hot enough to ignite fuel. At just the right time, a fuel injector squirts in a spray of diesel fuel. It burns immediately in the hot air, pushing the piston down.

In an HCCI engine, the injector squirts fuel while the piston is on the way up, like a regular gasoline engine. But the fuel doesn't need a spark. It combusts from pressure and heat alone, like a diesel engine.

Now here's the tricky part: getting the fuel to burn at just the right time without a spark or fuel injection to trigger it.

To set the stage, the engine's exhaust valve closes early, trapping some hot exhaust gas in the cylinder. A series of small jets of fuel squirt into the cylinder, raising the temperature and pressure to a critical point. When the time is right, the fuel ignites. The combustion doesn't start at one point in the cylinder and move outward, like it does in regular gasoline or diesel engines. It's a key reason HCCI is so efficient.

All this is tricky enough in a stationary engine humming along at a constant rate inside. But keeping it all going under the constantly changing demands of real driving is especially hard.

HCCI engines still have spark plugs to use in situations where HCCI just isn't very efficient. At high speeds, HCCI doesn't work well, so when a car is accelerating hard to merge onto a highway, the sparks plugs take over.

Where HCCI fits
During a recent test drive in a specially prepared Saturn Aura sedan with an HCCI engine, it was clear that the technology wasn't quite ready for the consumer market.

First of all, it's noisy. For those used to a quiet gasoline engine or an equally noiseless modern diesel engine, the popping and cracking noise from the Aura's HCCI engine would be simply unacceptable.
 

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Car companies? No. It's just GM.

Seriously... does the media not know how to say something nice about an American automaker?
Ford continues to investigate HCCI as well.
GM is not the only one. It is farther out than many think.

We may as well get used to automakers like GM rushing all kinds of technologies to market, ready or not, so that they can lay claim to being first. That is not safe for us.
 

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Ford continues to investigate HCCI as well.
GM is not the only one. It is farther out than many think.

We may as well get used to automakers like GM rushing all kinds of technologies to market, ready or not, so that they can lay claim to being first. That is not safe for us.
Thats why the smart customer will wait a few years when the bugs are worked out. However, I wouldn't release this kind of engine until I knew it was as reliable as a normal I.C. engine.
 

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One of many technologies GM is currently working on to increase fuel economy across the board. HCCI, an much improved BAS system (+), the Two Mode in larger cars and the crossovers. Also camless engines, turbo charging, better use of Direct Injection technologies. Lots of stuff planned! The next few years should be interesting to say the least.
 

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I know its good that GM is investing in this new kind of engines but please GM shut up and dont let the competition know about this , its like with the Volt and Camaro, hell work on the project and when the car or engine is ready take everybody by surprise and then say you will start production in 3 months , hell Ford is testing about 20 prototypes of the plug in based on the escape to check how the batteries perform , but not everybody has to know it
 

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Honda is supposed to be close, but they're more secretive than GM so its hard to know for sure.

BMW and another German company are preparing camless engines for the mass market. Supposedly the other German company will have them ready by about 2010. No word from BMW.

Looks like a lot of cool tech will be coming out in the next few years.
 

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First of all, it's noisy. For those used to a quiet gasoline engine or an equally noiseless modern diesel engine, the popping and cracking noise from the Aura's HCCI engine would be simply unacceptable.
People drive me nuts... the noise will most likely go away with sound reduction tech. like foam and such. AND the engine is also still in prototype form. Im sure the noise issue will be addressed.

If this was something coming from Toyota or Honda the media would make it out to be the best thing ever invented for the automobile!
 

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I know its good that GM is investing in this new kind of engines but please GM shut up and dont let the competition know about this , its like with the Volt and Camaro, hell work on the project and when the car or engine is ready take everybody by surprise and then say you will start production in 3 months , hell Ford is testing about 20 prototypes of the plug in based on the escape to check how the batteries perform , but not everybody has to know it
Honestly if GM is really hellbent on not getting people to copy the tech, they would have got a international patent a while ago.
 

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The 15% can't come soon enough. I really hope that they can get it to the market quickly.
 

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Volts are the obvious application.
With constant speed and load they should be able to run HCCI all the time.
 

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Honestly if GM is really hellbent on not getting people to copy the tech, they would have got a international patent a while ago.
I know its good that GM is investing in this new kind of engines but please GM shut up and dont let the competition know about this , its like with the Volt and Camaro, hell work on the project and when the car or engine is ready take everybody by surprise and then say you will start production in 3 months , hell Ford is testing about 20 prototypes of the plug in based on the escape to check how the batteries perform , but not everybody has to know it

GM NEEDS the publicity. We have been saying here that the quality of the GM cars are vastly improved but no one is stopping by the lots to check them out. This kind of publicity, if well placed, CAN bring people to the lots and possibly result in sales.
 

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I've personally seen a running Honda HCCI engine in Troy, OH. This was in '05. It ran pretty well at idle and above idle, but then ran pretty crappy other than that.
 
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