new combustion for gas engines...

[repoe3]

interesting little tidbit:
http://www.msnbc.msn.com/id/20423272/

repoe3

[throttlemeister]

Honda already has a similar system in production, but I can't think of the model. And that's pissing me off.

[markjenn]

That's a crappy write up in MSNBC: "...The process ignites an air-fuel mixture in the cylinders by compressing it....". Dah.

Reading between the lines, I assume the principle must be to use a diesel-like higher CR to raise efficiency, but do something with the charge to get it to oxidize without damaging detonation on cleaner gasoline fuels. I don't think there is any way to get dramatically higher combustion efficiencies these days without a higher CR.

Now aware of anything Honda is doing along these lines. They were active in stratified charge engines (CVCC) a long time ago but this sounds like the completely opposite principle. Honda has annouced a diesel development program.

- Mark

[Anton]

Honda produced and sold a HCCI bike. The EXP-2, a two-stoke dual sport.

HCCI is controlled knock. It is typically achieved with a lean mixture, high compression, and lots of exhaust gas recirculation (EGR). The EGR does two things, it raises the intake temperature making ignition easier, and the chemical compounds present in the exhaust help to start combustion. There are several problems with HCCI. Since it works best with lean mixtures, and by lean I mean waaaay lean, think equivence ratio of .3 of .4, it produces low power. The other problem is control, since there is no spark plug to initiate combustion, when the fuel lights off is a function of mixture, intake temp, cylinder wall temp and EGR amount. Because of this, it works best for steady state operation. The design of a production engine, would be to run as a spark engine during startup and transient operation, and switch to HCCI mode during steady state cruise.