Originally Posted by
littleteapot
I have a DAMOS file for the Z19DTH (Fiat variant), and couldn't see any maps relating to injection timing (SOI) correction by EGR flow. So probably not. There are SOI correction maps for air temp, coolant temp, etc but can't see one for EGR.
I believe the SOI maps are calibrated assuming 'normal' egr operation. But the effect of EGR on the required SOI is so small its not worth worrying about.
In fact, the standard SOI maps are actually retarded a little from the ideal value under light-load cruising conditions as a measure to further reduce NOx emission. Therefore once egr has been disabled thus increasing the burn rate of the injected fuel, the standard SOI map is probably closer to being ideal for economy. This may explain why I've seen better fuel economy on long journeys after disabling EGR.
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