Hi Guys, I finally used the thermomechanics approach to solve the fluid flow through a nozzle and it gives me very accurate results. Thank you for your review and the crucial hint with a sonic flow.
@gruntguru: The VE for various manifold pressures and RPMs (VE table) are determined on the real engine running on the dynamometer. At the beginning, we do not know the VE since it depends on a real engine dynamic flow behavior (camshaft shapes, combustion chamber shape, intake/exhaust ports...
Good idea. Thanks for that. Are we sure that the critical pressure is not reached? When idling, the pressure ratio is 140 kPa : 40 kPa = 3.5 : 1. I'll try to calculate tomorrow.
I Continued to find what's wrong.. I tested the dynamic behavior of the injector on the target system - replaced the vapor LPG supply to the injector rail by a pressurized air with a constant pressure and remove the outlet hose of one injector from the intake manifold fitting and measure the...
Yes, there are a fuel pressure and temperature sensors on the injector rail. One injector pulse per cylinder working cycle. Both manifold air pressure and fuel pressure seems to measure correctly since they indicates 96.8 kPa on atmospheric pressure, which corresponds to the current altitude.
Hi Lou Scannon, thank you for reaction. I'm aware of the uncertainty of the air or fuel temperature and the volumetric efficiency. However, the difference between the calculated and really needed fuel mass is too big. To get the fuel mass matching, I need to set the VE more than 1 or consider...
Hello All. There is a vapor LPG port fuel injection. Speed-Density air mass estimation is used. However, my calculations seems to be incorrect (the calculated injector pulse width does not produce a correct mixture) and I do not know what can be wrong. I really appreciate any kind of review or...
