Most efficient IC recip engines
Most efficient IC recip engines
(OP)
And what are the BSFC numbers for them?
I can think of one gasoline engine in the 50's running in the range of .32 lbs / bhph.
And .26 for a diesel engine.
I can think of one gasoline engine in the 50's running in the range of .32 lbs / bhph.
And .26 for a diesel engine.





RE: Most efficient IC recip engines
https://en.m.wikipedia.org/wiki/Brake_specific_fue...
RE: Most efficient IC recip engines
You mean 0.42? The latest Prius has the highest thermal efficiency of any mass produced gasoline engine - around 40% TE (0.32 lb/hp.hr)
On a more serious note, the current Formula one engines have peak efficiency in excess of 50%. (0.28 lb/hp.hr)
je suis charlie
RE: Most efficient IC recip engines
The Wiki list is funny because it lists a combined cycle power plant, and includes the generation of the steam cycle.
The eff of some old aero engines is impressive.
The fact that ICE is most eff at WOT and max torque makes hybrid design interesting...
= = = = = = = = = = = = = = = = = = = =
P.E. Metallurgy, Plymouth Tube
RE: Most efficient IC recip engines
Do these BSFC curves take into account the "Power Enrichment" that is needed at higher load (presumably max torque is max load by BMEP?), or do they presume an impractical stoich mixture at all operating points? I'm kind of surprised that reduction in pumping losses from the WOT manages to overcome the big fuel squirt needed to prevent detonation.
Pretty impressive numbers from those old aircraft engines, and the larger displacement stuff in general.
RE: Most efficient IC recip engines
RE: Most efficient IC recip engines
The Wiki list is funny because it lists a combined cycle power plant, and includes the generation of the steam cycle.
The eff of some old aero engines is impressive.
The fact that ICE is most eff at WOT and max torque makes hybrid design interesting...
1. No. KERS energy starts at the ICE, is used to accelerate the car, is recovered during braking and stored, then used again - recycled. Nothing to do with efficiency of the iCE.
2. As it should. The steam cycle is still generation useful energy from the same fuel going in. Efficiency = (useful output)/(cost of producing that output)
3. Yes. The Wright Turbo Compound and the Napier Nomad (also a compound) in particular.
4. Not universally true. Because more output is available with richer (fuel wasting) mixtures, most SI ICE's are more efficient around 70-80% load. The rpm for peak efficiency is usually close to peak-torque-rpm but not always. Yes hybrid design is interesting. There are BSFC maps for Priuses gettin around the net which include a "peak efficiency line" ("Basic Operating Line")- a plot of best efficiency point at various power levels - which is clearly where you ideally want to be with a hybrid (or any other) transmission.
Link
je suis charlie
RE: Most efficient IC recip engines
You mean 0.42? The"<<<<<END QOUTE...
.32 is the number.
RE: Most efficient IC recip engines
That's an incredibly low value for an engine from that era.
RE: Most efficient IC recip engines
PJGD
RE: Most efficient IC recip engines
RE: Most efficient IC recip engines
Correction
115/145
RE: Most efficient IC recip engines
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Greg Locock
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RE: Most efficient IC recip engines
RE: Most efficient IC recip engines
Link
Efficiency is well summed up in the following sentence:
" Of all the power generated, some goes to work, some goes to friction, some goes to heat, and the rest goes to hell, which is all that you could expect under the circumstances."
Bill
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"Why not the best?"
Jimmy Carter