Valve Event Optimization in a Spark-Ignition Engine

A computer simulation has been developed to study the effects of valve event parameters (lift, duration, and phasing) on spark–ignition engine performance. The zero–dimensional model employs polynomial and dynamic techniques to generate cam profiles for valve event optimisation. The model was calibrated and validated against data from a General Motors 2.5 litre engine. The simulation was then used to determine optimum valve events under different engine conditions. This insight was used to improve the cam design. Subsequent engine testing confirmed that a 3 per cent improvement in peak torque could be obtained with the optimised cam.