[Vwdiesel] Rabbit talk for beginners ---( Back to basicks )

[Libbybapa at wmconnect.com]

In a message dated 12/8/05 9:16:01 AM US Mountain Standard Time, 
svend at prcn.org writes:


> Andrew please explain  "Pumping Losses" ---- You totally lost me 
> there.---BUT it sounds
> interesting to me.  ------------  TIA.
> 

There is a certain amount of energy loss with regard to pumping air into and 
out of the cylinders.  If you lean a turbo diesel out beyond the point where 
you burning more fuel you are merely pumping air into and out of the engine.  
That pumping action creates inherent losses due several factors.  Primarily to 
the added backpressure between the turbo and piston.  Granted there is some 
gain due to the added pressure of the intake air pushing onto the opposing 
piston on the intake stroke, but there are significant energy losses in just 
pumping air.  So, to sum up, just pumping more air into the cylinders consumes 
energy.  If you are not gaining more energy than you are losing from getting a 
better (more complete) burn then you are merely consuming energy and decreasing 
overall fuel economy.  Super-lean is not super-economical in a TD.

Andrew

Andrew