Lean burn-thoughts, theorys, and discussion

[gone-ot]

...GOOGLE on "HCCI" or Homogenious-Charge Compression-Ignition.

...diesel-like operation at low-speed cruising with reversion to spark-ignition for controlled burn periods during accelerations.

...here's an old GM test article:

http://green.autoblog.com/2007/08/26...s-hcci-engine/

[frank316]

HCCI engines are pretty cool in theory but would require a LOT of engineering to get it right, not to mention a heavy ass block to withstand the constant abuse of "detonation" the main principal there operating under.. Lean burns much more of a practical application.

I'm currently working on building a new engine for the beater. It all used parts that people were planning on throwing away or I had laying around. It'll be around 10-1 compresion with flat top pistons, a head that has much larger quench pads and much tigter piston to head clearence than a normal engine would have, it'll also be slightly less displacement (1.5L vs the 1.6L) thats currently in the car. It will have a vtec head that has a "smaller" camshaft profile than whats in the car now (when vtec is not engaged), and hopefully when in vtec it will make a little more power.

Ben

[bestclimb]

A goodly chunk of the increase in efficiency of LOP is that you are opening your throttle farther for less vacuum.

[Tygen1]

Frank316, do you have an instant mpg readout to see what your mpg is at a 20:1 AFR at 50-55mph?

[frank316]

No I do not, been thinking about building myself a mpguino, but haven't got around to it yet. And I relize running leaner lets you open the throttle more and decrease pumping losses, but it gets worse gas mileage past 20-1 than it does below it, not sure whats up with that but don't have the instrumentation to see everything thats going on. The cars converted to run obd1 so I can't use a plug n play scan-gauge or any of the like, the obd2 port doesn't work.

Ben

[JasonG]

Any update Ben ?