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Old 11-13-2006, 08:26 PM
MTUpower MTUpower is offline
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Quote:
Originally Posted by ConnClark View Post
It holds true in a diesel

Go here and plug in 1.27 for gamma and use the defaults for the rest of the settings. http://hyperphysics.phy-astr.gsu.edu/hbase/thermo/diesel.html You should get a thermal efficiency of 42.467% . Now lets say you upped the boost or cooled the intake charge enough to raise gamma .03 to 1.3. Thermal efficiency rises to 45.872% .

To calculate the percentage of power gain
(45.872/42.467 - 1)x 100 = 8.017%


It also holds true experimentally

"As the boost pressure increase, the rate of heat release is resemble to the injection rate and becomes sharper and combustion improves and also the brake thermal efficiency becomes better. The high boost and lean diesel combustion results in low smoke, ISCO and ISTHC without the ISNOx increase and gives good thermal efficiency."
http://www.jstage.jst.go.jp/article/jsmeb/48/4/648/_pdf


If you want to argue that it doesn't hold for prechamber engines here is a few tests done by NACA in the 30's . (Note the Fuel consumption lb/hp per hour part of the graphs (lower = more power per same amount of fuel))
Great- Thanks. I think somewhere in there it proves bumblebees can't fly also. Folks- in the real world, just adding boost will make nearly no difference.
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