Stratified Charge DI with EGR

[Bernd Felsche]

Mike writes:
>At 05:10 PM 11/3/2000 -0700, you wrote:

>>>>The complication has its rewards; 15% less fuel consumption, partly
>>>>due to increased "volumetric efficiency" because the throttle is
>>>>often wide open... better find an updated abbreviation to replace
>>>>WOT!

>>It would be far more accurate to call this "decreased pumping losses" than
>>"increased volumetric efficiency".

>Yes thats a good point, because with higher EGR it takes energy to pump this
>inert gas around the system - I would have thought not that efficient.

>Decreased pumping losses for 'fresh air' would be spot on...

Well, the EGR isn't actually pumped - it's vented according to the
literature which only indicates a valve to regulate the amount of
EGR. The manifold pressure is also sensed, probably so that the
amount and rate of EGR, as much as ensuring that you have a pressure
drop when the control valve opens.

The necessary energy must still be available at the exhaust to pump
its way around - that's normally "wasted" - unless you have a turbo.

-- 
Real Name: Bernd Felsche
    Email: nospam.bernie at perth.DIALix.com.au
     http://www.perth.dialix.com.au/~bernie - Private HP
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