From WIKI FWIW: Most steel engines have a thermodynamic limit <http://en.wikipedia.org/wiki/Thermodynamic_limit> of 37%. Even when aided with turbochargers and stock efficiency aids, most engines retain an *average* efficiency of about 18%-20%.[9] <http://en.wikipedia.org/wiki/Internal_combustion_engine#cite_note-9> Rocket engine efficiencies are much better, up to 70%, because they operate at very high temperatures and pressures and can have very high expansion ratios.[10] <http://en.wikipedia.org/wiki/Internal_combustion_engine#cite_note-10> Electric motors <http://en.wikipedia.org/wiki/Electric_motor> are better still, at around 85-90% efficiency or more, but they rely on an external power source (often another heat engine at a power plant subject to similar thermodynamic efficiency limits).
[9] "Improving IC Engine Efficiency" <http://courses.washington.edu/me341/oct22v2.htm>. Courses.washington.edu. Retrieved 2010-08-28. [10] Rocket propulsion elements 7th edition-George Sutton, Oscar Biblarz pg 37-38 I am not sure how gasoline, diesel, hydrogen, propane, natural gas and so on are not external sources... I think it would be best to look at an integrated efficiency over a representative cycle of use. Also from the WIKI: The largest internal combustion engines in the world are two-stroke diesels, used in some locomotives <http://en.wikipedia.org/wiki/Locomotive> and large ships. They use forced induction <http://en.wikipedia.org/wiki/Forced_induction> (similar to super-charging, or turbocharging <http://en.wikipedia.org/wiki/Supercharger>) to scavenge the cylinders; an example of this type of motor is the Wärtsilä-Sulzer <http://en.wikipedia.org/wiki/W%C3%A4rtsil%C3%A4-Sulzer_RTA96-C> turbocharged two-stroke diesel as used in large container ships. It is the most efficient and powerful internal combustion engine in the world with over 50% thermal efficiency <http://en.wikipedia.org/wiki/Thermal_efficiency>.[4] <http://en.wikipedia.org/wiki/Internal_combustion_engine#cite_note-bmmWW-4> [5] <http://en.wikipedia.org/wiki/Internal_combustion_engine#cite_note-5>[6] <http://en.wikipedia.org/wiki/Internal_combustion_engine#cite_note-6>[7] <http://en.wikipedia.org/wiki/Internal_combustion_engine#cite_note-7> For comparison, the most efficient small four-stroke motors are around 43% thermal efficiency (SAE 900648); size is an advantage for efficiency due to the increase in the ratio of volume to surface area. On Thu, Sep 18, 2014 at 12:23 PM, Jan Steinman via EV <[email protected]> wrote: > > From: jerry freedomev via EV <[email protected]> > > > > First let's be more accurate, > > 'a gas car is only 7% eff, not 30% in car service > > Interesting. Do you have any documentation for that figure? What does that > 7% include; is it "well to wheels" or some other figure that includes a lot > of externalities? > > My understanding is that "pump to wheels" efficiency for ordinary, routine > use is pretty close to 30% for gasoline, approaching 40% for diesel. > > :::: The first priority for society as a whole is to drastically reduce > consumption of fossil fuel energy and products derived from fossil fuels. > The key action is to curtail. That means buying less, using less, wanting > less and wasting less. To curtail means to cut back or to downsize. Curtail > reflects the seriousness of the current situation more than the politically > acceptable word "conserve." -- Pat Murphy > :::: Jan Steinman, EcoReality Co-op :::: > > _______________________________________________ > UNSUBSCRIBE: http://www.evdl.org/help/index.html#usub > http://lists.evdl.org/listinfo.cgi/ev-evdl.org > For EV drag racing discussion, please use NEDRA ( > http://groups.yahoo.com/group/NEDRA) > > -- Put this question to yourself: should I use everyone else to attain happiness, or should I help others gain happiness? *Dalai Lama * Tell me what it is you plan to do With your one wild and precious life? Mary Oliver, "The summer day." To invent, you need a good imagination and a pile of junk. Thomas A. Edison <http://www.brainyquote.com/quotes/quotes/t/thomasaed125362.html> A public-opinion poll is no substitute for thought. *Warren Buffet* Michael E. Ross (919) 550-2430 Land (919) 576-0824 <https://www.google.com/voice/b/0?pli=1#phones> Google Phone (919) 631-1451 Cell (919) 513-0418 Desk [email protected] <[email protected]> -------------- next part -------------- An HTML attachment was scrubbed... URL: <http://lists.evdl.org/private.cgi/ev-evdl.org/attachments/20140918/6f3b7fb2/attachment.htm> _______________________________________________ UNSUBSCRIBE: http://www.evdl.org/help/index.html#usub http://lists.evdl.org/listinfo.cgi/ev-evdl.org For EV drag racing discussion, please use NEDRA (http://groups.yahoo.com/group/NEDRA)
