Quote:
The engine we are looking at is a 'smart car' 800cc 3 cylinder, 2005-2007 generation. With an I3, I'm not sure if the pressure waves will be as terrible, since the injections are spread out so far.
I would agree especially with only one injection
Quote:
I don't have cylinder pressure sensors yet, but I expect to need them.
It would be a great help.
Quote:
For gas controls I calculate air mass into the engine as one of the critical calculations. For diesel I was thinking of soot limit based on this air mass calculation, which would require a lambda sensor for cal only.
If you dont use egr you can just do fuel/boost pressure. For egr you need to have a maf sensor.
Quote:
For gas we currently do a sort of torque control, so it makes sense to continue doing it.
Frankly, for your needs I do not see the point.
Quote:
With pressure rise rate limits at high load, would a pilot injection help to reduce the pressure rise rate
Yes of course.
Quote:
/is a pilot injection normally used to extend high load operation?
The opposite actually.
Quote:
For emissions, the engine already has basic EGR. Since the engine can pass EU4 levels already, and we don't need to be that good, we can probably get away without EGR, or only EGR at very low loads/idle.
I do not know what limits you have but a bit of egr will decrease nox by ~50% and not raise bsfc.
Quote:
From what I've seen, it looks like EGR control for diesels is based on a minimum lambda vs speed/load table,
Not from what I have seen.
Quote:
so it allows as much EGR as possible using either lambda calculated from MAF or a lambda sensor.
What if you think like this: Do a mapping without egr. Measure the air flow with the maf sensor. Open up the egr valve gradually (Need to check the differential pressure, make a model.). The difference in air flow is the amount of egr. Increase egr until your emission levels are reached, bsfc increasing and or soot is increasing (You need a smokemeter or a opacimeter).
So you need a maps with speed and fuel weight/stroke on the axis with:
Boost pressure.
Rail pressure.
SOI
Air mass (This is egr).
The lambda sensor is not needed, only for calibration. It really is that simple.
You will probably come to the conclusion that you want high rail pressure, advanced timing, low boost pressure and low levels of egr. This way of calibrating is great for bsfc not so for NVH and emissions..