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Old 06-05-2012, 02:46 PM
TDIwyse TDIwyse is offline
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Location: Midwest
Join Date: Sep 2010
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Mein Auto: 4 diesels
Originally Posted by hotrod2448 View Post
So being new to diesel tuning, I'm assuming injection angle references crank position and by beginning injection earlier is not only adding fuel by increasing duty cycle but, it is also similar to adding ignition timing in a gasoline motor, right?

My next question is do we know if the ECU has some type of detonation protection that retards injection timing like a gas car would pull ignition timing if something were to see ridiculously high loads or something go wrong?
This place has some good info on tuning turbo direct injected engines and what's involved. It goes into injection timing, boost, EGT's, etc.

Yes, the injection angle data is for the "main" injection event. Up to a point, increasing the start of injection can improve thermal efficiency, power, at the expense of some emissions like NOx.

The car actually has 5 injections it uses. 2 "pre" injections, 1 "main", and 2 "post" events. The "pre" injections tend to fall off and stop at higher rpm's. The "post" events seem to mainly be used for DPF regens to maintain the correct temp in the burn-off. Interestingly I was once driving my car in a heavy downpour on the interstate when it tried to execute a DPF regen. Based on watching the EGR rate and instantaneous mpg gauge it was unable to do it correctly and kept trying for over an over until I reached my destination. Next time it got drove the weather was dry and it immediately went into regen mode and completed successfully. Worst mpg tank by far. This is something to consider if people start venturing into water injection stuff . . .
2011 335d 11.8 sec 120 mph 1/4 mile NHRA certified track

2004 Ram Cummins with lots-o-mods
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