A Joint Simulink Boost Power Converter and Injector Valve Model 2006-01-0853
We describe a Joint Boost Power Converter and Injector Valve Model that we used to help develop and optimize the Woodward ECM3, 24 channel EFI driver system.
Using the joint model, we found that the adaptive algorithm used to drive the injectors would not suffer from a non-stiff bus voltage as long as we could achieve the required valve closure time. The joint model then helped us find the optimum combination of IL, L, Vbus, Cbus, Coil Current Profile and the Average Power with respect to the valve closure time constraint. In addition, we used the model to gain insight into the effect of Pull-In Current levels on the Valve Closure Locus and the valve position response when a Pre-injection pulse is added to the Main-Injection cycle.
We include the details of the low frequency average model for the boost converter together with the physics based injector model incorporating hardware delay, inertia, spring, friction, measured force (or Back EMF) map, inductance and resistance augmented with some non-linear characteristics. Superimposing measured and model predicted Coil current and Vbus voltage validates the quality of the joint model. We also discuss the Closure Locus and Pre-/Main-injection interaction results.
We will lead to the conclusion that individual or separate optimization of the injector valve and power supply is sub-optimal.