Engine control using estimated parameters from a real time model of an engine with variable valve actuation

A real time model of an engine was developed and integrated with engine control software to provide better engine control with less calibration effort. The model uses one-dimensional compressible gas wave equations for the intake and exhaust system along with a thermodynamic model of the cylinder to provide real time estimation of the cylinder air charge, exhaust gas residual mass fraction, cylinder pressure, cylinder temperature, and various other states along the intake and exhaust system. Information from the model is used to control the fuel injection, spark advance, valve timing, and throttle position on the actual engine. The system does not use any volumetric efficiency tables. Since the real time model responds like the actual engine there is no need for transient fuel or transient spark advance correction factors. The estimated cylinder pressure is used to calculate the instantaneous indicated engine torque and engine efficiency. Using the model it is possible to optimize efficiency, control the torque output, and regulate the exhaust gas residual mass fraction. The system offers many control advantages and is easy to calibrate.