Chronology Current Month Current Thread Current Date
[Year List] [Month List (current year)] [Date Index] [Thread Index] [Thread Prev] [Thread Next] [Date Prev] [Date Next]

Re: [Phys-L] definition of "power"




On 2014, Dec 01, , at 12:23, Richard Tarara <rtarara@saintmarys.edu> wrote:

Similarly thinking about a plug-in electrical car being powered by a coal-fired plant might not be as friendly as one might hope,

yes, but

and might not be much better than driving a high-mileage gasoline car.


Only part of that story — remember that it never idles and the brakes don’t heat, instead charging the batt. is the braking, also down hill charges. I suspect that no matter the condix. an all electric is better, and a hybrid is a very much so.

bc ’s a 130K miles and no brake job!

Another: For the hybrid, less use of the ICE, so longer service life, with concomitant greenness. And remember an elec. motor converts chemical, and thermal E considerably more efficiently (to mechanical) than an ICE. Here’s an interesting and, i think, physically correct page from TESLA.

Energy Efficiency of Tesla Electric Vehicles | Tesla Motors

http://www.teslamotors.com/goelectric/efficiency

bc can’t afford a TESLA.

Furthermore, more, if not all, hybrids use an Atkinson cycle which is more efficient than the Otto.

Atkinson cycle - Wikipedia, the free encyclopedia

http://en.wikipedia.org/wiki/Atkinson_cycle

typical ICE (Otto) 20% “thermal efficiency”, Prius 38%

Believable from Consumer Reports?

Toyota Gasoline Engine Achieves Thermal Efficiency Of 38 Percent

http://www.greencarreports.com/news/1091436_toyota-gasoline-engine-achieves-thermal-efficiency-of-38-percent


I wondered why no Diesel hybrids, wrong:

https://www.google.com/search?client=safari&rls=en&q=diesil+hybrid&ie=UTF-8&oe=UTF-8#rls=en&q=diesel+hybrid&spell=1

Unfortunately, greater exhaust pollution.