Cylinder Deactivation and Propulsion Electrification

Cylinder deactivation is a technology that allows the engine displacement to be varied to match vehicle acceleration and power demand. This is typically accomplished by turning off banks of cylinders, to go from, say, an 8-cylinder engine to a 4-cylinder engine and vice versa. Dynamic Fuel Management is a term used to describe the continuous use of cylinder deactivation in such a way that various cylinders are shut off in a variety of combinations, maximizing fuel economy and avoiding switching between banks of cylinders. Such an engine operates with lower pumping losses and maximizes the potential for regenerative braking energy capture. In the present work we explore the synergies of coupling an engine equipped with Dynamic Fuel Management, to an electrified driveline hybridized with a 48 V motor. The so-called P1 architecture is investigated, wherein the motor is connected to the engine crankshaft at the flywheel between the engine and transmission. We use detailed Matlab models combined with an optimization algorithm that determines engine/motor torque arbitration to identify optimal powertrain states to maximize fuel economy. We show that the combination of Dynamic Fuel Management and hybridization can provide a substantial fuel economy improvement.