Optimal cold start calibration of spark ignition engines

This paper investigates optimal strategies for minimising the conflicting objectives of fuel consumption and warm up duration following an engine cold start. Using a reduced order model, parametric solutions for the optimal air-fuel ratio, valve timing, cam timing and idle speed setpoint are sought in the presence of input constraints. The results are then validated using a dynamic programming approach on a high fidelity engine model, and compared experimentally with a production calibration for an inline 6-cylinder, SI gasoline engine. The methodology used can be readily extended to other mixed objective problems, and can be a useful tool in decreasing engine calibration time.