Quote:
Originally Posted by cut7
Yes it makes sense. I see what you're saying, but I'm not sure I agree with you. Having said that, it's always good to consider dissenting opinions; especially from a fellow mechanical engineer. I guess a good place to start would be find out what max timing is on a performance common rail tune that does not make use of pilot injection. Anybody want to contribute that info?
BTW, the curve you've suggested is exactly what I plan to do. (Great minds think alike!)  |
Good deal.
So the reason I'm confident that injection timing will play a role is because 13mm pumps use different timing based only on the fact that they have a ~17% larger bore and inject fuel much quicker because of this. Do you know the stroke, bore, and ramp of your pump? That might get you an idea as to where you want to start.
Have you gotten the pump flow tested to see how much fuel you'll have. That can give you a hint as well for timing.
As for common rail injection, I would assume they have a much quicker injection event than a 12mm pump at most rpm ranges.
Quote:
Originally Posted by cut7
I am reading the RPM — & other several factors — from the CAN bus; which is getting it's RPM data from a 60-2 reluctor wheel on the damper, read by a 0-5v Hall-effect sensor. From there, my controller commands the timing & fueling racks; the timing based on a table. It also controls the waste gate of my compound turbos; but that's not relevant to this conversation.
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Have you done any testing on how fast it can actuate? I would assume there's some lag, so if you're using an Arduino to control this, look up smoothing functions. There's all sorts of free software out there for VGT control that would be very very similar to what you're doing.
All that stuff said, I really think you need to toss it on and just start playing with it. Timing is a funny thing and it seems to be +-2deg truck to truck to get the same outcome.
