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From: gvcormack@watdaisy.UUCP (Gordon V. Cormack)
Newsgroups: net.auto
Subject: Re: superturbochargers
Message-ID: <7199@watdaisy.UUCP>
Date: Fri, 19-Apr-85 11:29:53 EST
Article-I.D.: watdaisy.7199
Posted: Fri Apr 19 11:29:53 1985
Date-Received: Sat, 20-Apr-85 07:38:50 EST
References: <541@hou2e.UUCP> <2494@drutx.UUCP> <2505@drutx.UUCP> <1120@amdcad.UUCP>
Organization: U of Waterloo, Ontario
Lines: 21

> It takes engine power to push exhaust gases out of the 
> cylinder, and I don't think that a turbo charger makes
> it any easier.
> 
> Mike @ AMDCAD

This argument was also put forward in a previous round of discussion
a year ago.  The simple fact is that, by nature of the cycle in the
internal combustion engine, the exhaust is released at many atmospheres
of pressure.  Even if the exhaust were to a total vacuum, the kinetic
energy of the exhaust would be wasted.  The turbo harnesses this energy.
Of course, a turbine is going to increase the back pressure a bit,
but it need not do so very much.

The bottom line is that the first clause of the above quotation is
fallacious;  most of the energy pushing exhaust gasses out of the
cylinder is waste heat, not useful mechanical energy from the engine.
The turbine harnesses much more waste energy than useful energy.
-- 
Gordon V. Cormack      CS Department, University of Waterloo
   gvcormack@watdaisy.uucp     gvcormack%watdaisy@waterloo.csnet