Quote:
Originally Posted by naturalextraction
While droplet size from modern day injectors are quite small, in a hot chamber they still can create pinging or complete detonation damaging pistons or valves. Thus why engineers developed DPI for better fuel distribution with higher fuel pressures. Other factors that create anomalies from injected engines would be pump pressure consistencies due to possible voltage drops at pump, restrictions, fuel density changes due to ambient temperatures, to name a few.
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I have to ask here, you seem to be suggesting that droplet sizes influence autoignition events. Is this anomaly a result of the lack of latent heat of evaporation due to excessive size or something on a chemical level that only a chemist would understand?
Also, would you agree that detonation frequently occurs at lower, non-audible levels even in most factory engines?
Having been exposed to the world of ricepower, I believe to have achieved a moderate gain in economy by running fuel ratios leaner than stoichiometry. A drop in EGT's was evident, however, the best I could do was around 37 mpg straight hwy. This was a B18C1 with its rather large quench pads and unshrouded valves. I imagine the largest disadvantage was the terrible 5th gear. Eventually the same engine was fitted with turbo apparatus, large injectors, intercooler, and the usual paraphernalia for wasting petrol in the 1320'. What's interesting is that city and hwy mpg's decreased by about 3 mpg and when the engine would tolerate 16.5ish fueling in it's previous naturally asphyxiated form, it now prefers a tad richer and must idle at roughly 12.5:1 air/fuel. I've chalked this up to be the fault of Lucas type injectors.
So my hats off to you Mr. pgfpro for achieving numbers like that, although I am discouraged after reading your post about the B18B engine which is soon to be my next tuned and economy only guinea pig. I think an unorthodox compression ratio and an altered intake valve closing may be of benefit.