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Old 03-04-2009, 03:17 PM   #4 (permalink)
Shawn D.
Harebrained Idea Skeptic
 
Join Date: Jun 2008
Location: Alpharetta, GA
Posts: 211

The White Car - '84 Mercedes-Benz 300td
90 day: 28.84 mpg (US)

The Blue Car - '86 BMW 535i
Last 3: 23.86 mpg (US)
Thanks: 19
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Quote:
Originally Posted by Daox View Post
Why would we not want high EGR flow at idle and light loads? Pumping losses are the greatest when the throttle is closed or close to it. Low speed city driving mileage would be noticeably improved.
As the quote you used yourself said: "No EGR flow should occur during conditions when EGR operation could adversely affect engine operating efficiency or vehicle driveability (engine warm up, idle, wide open throttle, etc.)"

At low throttle openings and low engine speed, EGR makes the vehicle run extremely roughly -- I've experienced this myself.
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