Quote:
Originally Posted by old jupiter
The Wikipedia article (Mr. Taylor's link, above) cites two effects as gains, that are actually net losses. "Reduced Throttling Losses," comes because the throttle must be opened a little more to make up for lost power. Put your foot to the floor and you can REALLY reduce throttling losses, but are you saving fuel? And "Reduced Heat Rejection," again should have been noted as a measure of the fact that your heat engine has a cooler fire inside it with EGR. What we'd like to do is make the MOST heat, and get the most out of that heat, with the smallest amount of fuel, emissions aside.
Mechanic, I'm not picking on anyone, and anyone reading Mr. Webb's posts can see he's a smart guy.
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At the same average speed more throttle (via P&G or taller gearing) on most vehicles will reduce fuel consumption. The problem with higher peak combustion temps is that engines aren't perfect containers of heat, so the more heat that's made, the more we loose. Depending on the materials increasing combustion temps may not yield any gains.
Quote:
Originally Posted by mwebb
[COLOR="Blue"]EGR does not have any effect on Air fuel ratio
EGR does NOT make the system richer
EGR does NOT make the system leaner
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It depends on the system. If something is carb'ed with no feedback or post mixture feedback (eg a smog pump), then EGR will make the system a bit richer. If the system has O2 feedback then you're right, whatever regulates the A/F mixture will cut back on fuel to keep it at stoich.