Quote:
Originally Posted by Cycle
So that observed 5% difference in BTU/mile fuel efficiency may just be because propane burns leaner than gasoline.
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Sense OEM gasoline ICEs have run up to 25:1 Lean Burn ... I doubt (haven't seen documentation supporting) that any further leaner would yield any significant (measurable) benefit (ie the 5%) in BTU/mile .. or in raw BTU/BTU energy efficiency.
Quote:
Originally Posted by Cycle
But that's only 1.3548% fuel to air by volume
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No.
A 5% improvement in BTU/mile does not itself tell you what the AFR was ... Only that is was in the range to still allow the engine to function.
Quote:
Originally Posted by Cycle
So the propane burning hotter would give greater thermal expansion of the air in the cylinder, thus more cylinder pressure.
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Always boils down the energy (BTU) ... which is the capacity to do work .. ie move the piston ... or move the air .. change the temperature of the air .. or move the car.... etc.
Changes in temperature without changes in the energy content (BTU) will not change the total capacity to do work ... even heating the air type of work.
Quote:
Originally Posted by Cycle
Which makes it hard to believe it would have a higher BTU/mile in the first place.
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Feel free to ask him for his records / references ... I'd suggest doing so nicely .. 'more flies with honey' as the saying goes.