- Fri Jul 07, 2023 2:21 pm
#63885
The deadtimes change because of the change in magnetic force, the change in magnetic force is proportional to the square of the current and the current changes because the resistance of the copper winding changes with heat. The resistance change is approx. 40% over 100C. The inductance of the injector does not change appreciably, at least in my experience.
How much variation do you get in fuel temperature? the injector temperature will be a combination of fuel temperature, coolant temperature and intake air temperature. OEMs can model that with a reasonable degree of accuracy and correct for it. If you want to compensate for that in an aftermarket ECU then you would really need to measure the temperature of the injector itself or measure the current flowing through it to derive the coil temperature. The alternative, as I suggested above is to use a Peak/Hold driver which delivers a constant current and therefore a constant magnetic force.
How much variation do you get in fuel temperature? the injector temperature will be a combination of fuel temperature, coolant temperature and intake air temperature. OEMs can model that with a reasonable degree of accuracy and correct for it. If you want to compensate for that in an aftermarket ECU then you would really need to measure the temperature of the injector itself or measure the current flowing through it to derive the coil temperature. The alternative, as I suggested above is to use a Peak/Hold driver which delivers a constant current and therefore a constant magnetic force.