Prototype HCCI Engine Could Do 30% Better Than 06 HCH - GreenHybrid

Delta Flyer · #1 (**permalink**) 11-07-2005, 05:36 PM

Honda is making progress on an HCCI engine that if introduced on the 2006 HCH, would increase fuel economy 30% to 65mpg.

The HCCI is a lean-burn engine, but unlike the 5-speed Insight avoid the NO emissions. It ignites without spark plugs. The compression that detonates it is not quite like in a diesel. It can run on gas, diesel, biodiesel, natural gas, hydrogen.

Since GM is also working on this, I'm sure Honda is concerned.

Quote:

Originally Posted by Car & Driver

Called "homogeneous-charge compression-ignition," or HCCI, the new technique ignites a gasoline-air mixture by compression — a process similar to that used in a diesel engine — rather than by spark ignition, the story said. Apparently, vehicles powered by gas HCCI engines could potentially offer the fuel economy of a diesel without its high emissions of nitrogen oxides and sooty particulates, and when combined with an electric motor, as are today's hybrids, fuel economy could be stretched even more.

But it's a challenge to make an HCCI engine run smoothly at very low and extremely high speeds because of the difficulty in controlling spontaneous combustion in those ranges, the story said.

But, citing Honda engineers who spoke on the condition of anonymity, the company has been able to get a prototype four-cylinder HCCI engine to run smoothly in a low- to medium-speed range, about 65 percent of the load range necessary to run a gasoline engine properly on the highway, and is working on making it run as well above 4,000 rpm.

Story

UC Berkley explaination

Delta Flyer · #2 (**permalink**) 11-07-2005, 06:00 PM

Put an HCCI engine in a 5-speed Insight and the EPA highway milage is as great as 90mpg without factoring improvements in the assist, etc.

jdenenberg · #3 (**permalink**) 11-08-2005, 04:52 AM

Don't believe everything you read. The "30%" improvement is in the efficiency, not the absolute MPG. A good gas engine runs about 30% efficiency; Diesel about 40%. So improving the gas engine efficiency by 30% (optimistic number) gets it to 39% which is just below that of a diesel. just use a diesel in a hybrid for MPG, it's existing technology, (besides, there's more energy in a gallon of diesel fuel than in a gallon of gasoline - especially when some of the gasoline is replaced by ethanol). Here's a link to another HCCI article - it only claims 20% improvement, but again highlights lower NO emissions.

http://www.gm.com/company/gmability/...rd_081705.html

JeffD

Delta Flyer · #4 (**permalink**) 11-08-2005, 05:02 AM

If 20% gain is reputable, it's still a significant improvement. Yes, I was quoting the high-end....

hawkGT647 · #5 (**permalink**) 11-08-2005, 07:05 AM

This HCCI concept is interesting... it's something that Smokey Yunick experimented with. I think he had limited success with it, basically the engine was running in severe knock conditions.

The last I heard the HCCI engine would run fine until it was loaded, then detonation/pre-ignition would take over.

Question, how does the engine perform a cold start?
I thought it needed a preheated air charge.

Regards,

Delta Flyer · #6 (**permalink**) 11-08-2005, 07:07 AM

An interesting question: Can an HCCI engine do a cold start in sub-zero weather?

AZCivic · #7 (**permalink**) 11-08-2005, 07:33 AM

You can find a little more info here:

http://en.wikipedia.org/wiki/HCCI

The bottom line is that it might work well for generators and such that run at a constant, fixed load, but it's unlikely to find a home in automobiles any time soon. HCCI's advantages diminish rapidly when compared against more modern spark engines such as Honda's ultra-lean, high exhuast recirculation Direct Injection engine.

We're already starting to see some direct injection vehicles here in the US, some of which definitely offer better performance than their port injection counterparts, even without lean-burn. I'm a lot more excited to see advanced direct injection offerings show up in the next 3-5 years than HCCI which might be anywhere from 10 years off to never.

Delta Flyer · #8 (**permalink**) 11-08-2005, 07:38 AM

AZCivic,

I just skimmed that article. The HCCI reminds me of the scramjet - efficient only if it's at it's cruise speed.

The irony of Honda's HCCI work is it's probably better suited in an HSD - it would work better in a Prius.

clett · #9 (**permalink**) 11-08-2005, 12:14 PM

HCCI is ideal for a series hybrid.

The big question is who's going to be first to bring out a series hybrid? Toyota? Honda?

My bet is for an outsider - Mitsubishi. They've already committed to going down the full EV route with in-wheel motors etc. For the increased range and quick refill capability that many will demand, they're going to want to put in a small, clean, low emission engine in the back somewhere. HCCI would be ideal for this kind of onboard generator set up.... no need to worry about idle or torque or lag or throttle response, just outright thermal efficiency.

AZCivic · #10 (**permalink**) 11-08-2005, 01:02 PM

Mitsibishi's major problem is that they are going bankrupt in their consumer automotive business. If they do produce a series hybrid, it would likely be over in the industrial arm of the company that makes light delivery trucks, for example. Mitsubishi is another company that is big in direct injection too, although like all the other DI players, they still have not been able to match Honda's center mounted DI; they use peripheral mounted DI.