Abstract: A method of operating a series type hybrid-electric powertrain having an internal combustion engine, a generator, and a battery is provided. A state of charge level of a battery is estimated. The state of charge level estimate is compared to a first threshold. An internal combustion engine operates at a first engine speed setpoint and a first engine torque output setpoint when the state of charge level estimate is below the first threshold. The state of charge level estimate is compared to a second threshold. The second threshold is a lower state of charge level than the first threshold. The internal combustion engine operates at a second engine speed setpoint and a second engine torque output setpoint when the state of charge level estimate is below the second threshold. The internal combustion engine generates more torque at the second torque output setpoint.

Abstract: A method for controlling intake manifold oxygen for an engine having a fresh air inlet and an exhaust gas recirculation (EGR) circuit includes the steps of: establishing an ideal excess oxygen ratio for combustion in the engine; calculating a total mass flow of oxygen to be delivered to an intake manifold of the engine to maintain the ideal excess oxygen ratio; determining a mass flow of EGR oxygen in the mass flow of EGR gas; and controlling a desired mass flow of fresh oxygen to be delivered to the intake manifold such that the sum of the desired mass flow of fresh oxygen and the mass flow of EGR oxygen is equal to the desired total mass flow of oxygen, by re-adjusting the EGR valve.

Abstract: A method for controlling intake manifold oxygen for an engine having a fresh air inlet and an exhaust gas recirculation (EGR) circuit includes the steps of: establishing an ideal excess oxygen ratio for combustion in the engine; calculating a total mass flow of oxygen to be delivered to an intake manifold of the engine to maintain the ideal excess oxygen ratio; determining a mass flow of EGR oxygen in the mass flow of EGR gas; and controlling a desired mass flow of fresh oxygen to be delivered to the intake manifold such that the sum of the desired mass flow of fresh oxygen and the mass flow of EGR oxygen is equal to the desired total mass flow of oxygen, by re-adjusting the EGR valve.

Abstract: An exhaust back pressure control system includes a valve in the exhaust outlet of a turbocharger of an internal combustion engine which is controlled by an engine control microcomputer. When the valve is moved toward a closed position, it restricts the exhaust flow, thereby increasing back pressure and friction within the engine by producing an artificial load thereon, and thus speeds up the warming process taking place within the engine upon starting thereof. The valve is moved by an actuating piston within a hydraulic cylinder using engine oil pressure controlled by an electrically operated valve receiving a pulse width modulated operating signal from the engine microcomputer, the operating signal being generated to provide a desired back pressure as a function of engine coolant temperature, engine speed, engine fuel comsumption, and actual back pressure. Operation of the system is enabled if the ambient air temperature is below 2.degree. C.