I was reading John B. Heywood's book Internal Combustion Engine Fundamentals last night. Here's an interesting paragraph relevant to EGR
Quote:
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At part-load operating conditions, it is advantageous to dilute the fuel-air mixture, either with excess air or with recycled exhaust gas. This dilution improves the fuel conversion efficiency for three reasons: (1) the expansion stroke work for a given expansion ratio is increased as a result of the change in thermodynamic properties of the burned gases; (2) for a given mean effective pressure, the intake pressure increases with increasing dilution, so pumping work decreases; (3) the heat losses to the walls are reduced because the burned gas temperature are lower.
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