Fuel economy optimization in automotive engines

Automakers have introduced a number of devices, such as the exhaust gas recirculation valve and variable cam timing (VCT), intended to vary with operating conditions previously fixed by engine design. Scheduling set points for these devices and adjusting dependent parameters, such as spark advance, to optimize fuel economy and emissions typically require extensive engine dynamometer mapping. Exhaustively mapping all feasible combinations is prohibitive. Design of Experiments (DOE) has greatly reduced conventional engines mapping time and will be required for more complex engine configurations. On the other hand, caution must be exercised in applying DOE methods if the full benefit of new actuators is to be realized. This paper examines potential fuel economy losses directly attributable to steady state engine characterization by using a dual-independent VCT engine as the platform