Talk:Engine efficiency
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Just did a bit of spell checking (efficency->efficiency), apart from that this article has quite a few inaccuracy's. Don't have time to fix though.--Stripy42 14:01, 26 April 2007 (UTC)
I revised several factoids of the previous version. I based my input on mechanical-engineering textbooks in my possession but did not reference them. I hope that is not a problem.09:40, 4 October 2007 (UTC) —Preceding unsigned comment added by Raymondwinn (talk • contribs)
This article troubles me. In particular, the material below troubles me. It does not make any sense to me. I think it can lead to incorrect behavior. From where did this material come?
"Gasoline engines also suffer efficiency losses at low speeds from the high turbulence and head loss when the incoming air must fight its way around the nearly-closed throttle; diesel engines do not suffer this loss because the incoming air is not throttled. Engine efficiency improves considerably at open road speeds; it peaks in most applications at around 75% of rated engine power, which is also the range of greatest engine torque (e.g. in the 2007 Ford Focus, maximum torque of 133 foot-pounds is obtained at 4500 RPM, and maximum engine power of 136 brake horsepower is obtained at 6000 RPM)." —Preceding unsigned comment added by Ecarecar (talk • contribs) 17:26, 12 April 2008 (UTC)
"It should be noted that at lower power outputs, the effective compression ratio is less than when the engine is operating at full power, due to the simple fact that the incoming fuel-air mixture is being restricted."
What is an "effective compression ratio?" This needs a citation.
Compression ratio is defined as "the ratio of cylinder volume with the piston at crank-end dead center to the cylinder volume with the piston at head-end center." Van Wylen, "Thermodynamics," 1959 John Wiley & Sons, page 265.
The concept of "effective compression ratio" makes no sense. —Preceding unsigned comment added by 72.160.147.223 (talk) 17:45, 12 April 2008 (UTC)
