Patent ID: 8640458

Claim:
A method of controlling an engine including a combustion air boosting system supplying a flow of pressurized combustion air to the engine and including a supercharger mechanically coupled to the engine and a turbocharger disposed downstream from the supercharger, the boosting system including a combustion air bypass duct for bypassing a flow of air around the supercharger and a combustion air bypass valve for controlling the flow of air through the combustion air bypass duct, the method comprising: controlling an exhaust gas flow rate through a turbine portion of the turbocharger to maintain operation of the turbocharger within an operating range; adjusting a position of the combustion air bypass valve to adjust a flow rate of the combustion air through the combustion air bypass duct to create a negative pressure differential across the supercharger between an inlet of the supercharger and an outlet of the supercharger to generate a rotational output of the supercharger; and transmitting the rotational output of the supercharger to the engine through a mechanical connection between the supercharger and a crankshaft of the engine, wherein the rotational output of the supercharger is a defined as a torque applied from a drive shaft of the supercharger through the mechanical connection back to the crankshaft of the engine.