Abstract: A system and method are disclosed for controlling idle speed of an internal combustion engine. The system includes an engine speed sensor producing an engine speed signal indicative of a rotational engine speed of an internal combustion engine, and a control circuit. The control circuit controls the rotational speed of the engine between an idle speed reference and a maximum speed reference. The control circuit also modifies the idle speed reference as a function of the engine speed. Additionally, the control circuit may determine an engine acceleration rate as a function of the engine speed, and modify the idle speed reference as a function of the engine speed and the engine acceleration rate.

Abstract: The present invention relates to a system and method for managing the operation of a turbocharger and is responsible for controlling the turbocharger to cause a desired air mass flow to be provided to the engine and for protecting the turbocharger from excessive shaft speed and excessive turbine inlet temperature. The protection modes have higher priority than the performance control. First, turbocharger shaft speed is checked against a programmable limit, and the turbocharger is adjusted to bring the speed under control if its speed exceeds this limit. If the speed is not above the limit, the turbine inlet temperature is checked against a second programmable limit. If the turbocharger inlet temperature is above the predetermined limit, the turbocharger is adjusted to bring the inlet temperature under control.

Abstract: A turbocharger wastegate control system is responsive to electrical control signals to control the position of a wastegate valve positioned within an exhaust bypass conduit of the turbocharger. In one embodiment, the control system includes an air pressure control device having an inlet port receiving boost air pressure from an intake manifold connected to the turbocharger, an outlet port providing wastegate air pressure to a wastegate actuator and a vent to atmosphere. A number of air flow control switches are responsive to electrical control signals to control the levels of boost air pressure and vented air to thereby provide a plurality of discrete wastegate air pressure levels to the wastegate actuator. In another embodiment, the control system includes an electrically controllable wastegate actuator responsive to boost air pressure and electrical control signals to modulate the position of the wastegate actuator plunger.