From some "dyno type"measurements, monitoring petrol fuel energy usage in, and Kw generated out, A prius engine carburated is returning 17% at the 10kw level. (shaft estimated at 21%). This is run at 2000rpm, because of some other constraints, so maybe about the ball park. If anyone knows if this is so, please comment.
A switch to LPG, with a crude mixer,and regulated from BBQ bottle, enabled a 5KW run, but consumed around 3kg per hour. This came out at energy in to energy out of about 10% total, and maybe 12.5% shaft. My thoughts are further tuning, may improve this, but how about this idea.
The Prius engine shortens its inlet stroke lenght by leaving the inlet valve open for about 25% of the upward stroke. If the inlet valve cam gear was advanced on the timing chain, a higher compression ratio for the LPG could be obtained, maybe up to 13:1. Risk would be of the valve clipping the piston at the begining of the intake stroke, when in the vvt off position. Nice if this worked without a cam grind.
Any Ideas?