Use caution here folks Maximum FUEL efficiency and Maximum VOLUMETRIC
efficiency may or may not occur @ the point of peak torque. (I have engines
that achieve 112 % VE 3000 rpm PAST peak torque) Anyone who has studied the
pressure/mean curves can tell you depending on dynamic losses & friction
loss (as a fn. of rpm) these factors have a strong influence on
"effiiciency" either way. Also dont forget that a diesel has "odd"
stoichiometric qualities that skew when peak fuel effieciency occurs (again
if not maximized it will NOT occur @ peak torque.)
(holy cow now I need to go back & look @ my post-graduate I.C.E texts for
clarification)
----Original Message-----
From: wwd@netheaven.com <wwd@netheaven.com>
To: Military Vehicles Mailing List <mil-veh@mil-veh.org>
Date: Thursday, September 20, 2001 3:12 PM
Subject: Re: [MV] top speed of an M35
>In <list-1298504@skylee.com>, on 09/20/01
> at 02:48 PM, "ygmir" <ygmir@onemain.com> said:
>
>>I guess what I'm getting at is that I am told that an engine operates
>>most efficiently at the rpm where torque and horsepower curves intersect.
>>Can any one add to this theory? Or, am I getting to far afield........
>>Henry
>
>That is wrong, and is probably a confusion of the simpler 'truth' that is:
>
> Maximum fuel efficiency results when the engine is operated at the
>peak of its torque curve.
>
>Whether diesel or gas no matter, 4 cycle (2 cycle probably). The main
>reason why this simple statement is invariably true is that 'volumetric
>efficiency' is maxed at the peak of the torque curve, or the torque curve
>IS the volumetric efficiency curve. VE is maxed at a certain rpm due to
>gas flow considerations thru the entire engine, and combustion chamber
>shape, cam profile, valve shape and timing all contribute to the
>flatness-steepness of the torque curve and the location of its peak.
>
>Forget the horsepower curve- it has nothing directly to do with fuel
>efficiency/VE.
>
>Bill
>--
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>wwd@netheaven.com
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