Abstract: An exhaust gas recirculation (EGR) control system for an engine comprises a valve, such as an EGR valve, that controls recirculation of exhaust gas in the engine between an exhaust manifold and an intake manifold. A controller communicates with the valve and opens the valve after the engine is turned off to allow the exhaust gas into the intake manifold. The exhaust gas is therefore present in the intake manifold when the engine is next started. In this manner, the amount of fuel required to start the engine is reduced, and startup emissions are reduced.

Abstract: A method of determining the quality of subsystems of an electronic engine control system is provided. The method monitors an engine parameter representative of a subsystem of interest and compares the parameter to at least one quality limit. The at least one quality limit represents an acceptable performance boundary for a fully functional engine control system. The method then indicates, based on the result of the comparison, whether the subsystem is of satisfactory quality. The method is arranged, without limitation, to determining the quality of start time, start flare, idle control during transmission shift, and speed control.

Abstract: A method of determining the quality of subsystems of an electronic engine control system is provided. The method monitors an engine parameter representative of a subsystem of interest and compares the parameter to at least one quality limit. The at least one quality limit represents an acceptable performance boundary for a fully functional engine control system. The method then indicates, based on the result of the comparison, whether the subsystem is of satisfactory quality. The method is arranged, without limitation, to determining the quality of start time, start flare, idle control during transmission shift, and speed control.

Abstract: A spark control method for a vehicle engine is provided for enhancing engine performance and fuel economy prior to a fully warm state. The spark control method is based on coolant temperature and engine speed while accounting for an engine position and time from the start-to-run transfer. More particularly, the methodology of the present invention initially determines if the desired spark advance is before top dead center and if the throttle is open. If so, the methodology loads engine speed and coolant temperature to the engine control unit and interpolates a spark advance multiplier value. Thereafter, the current engine position pulse is loaded and an engine position pulse multiplier is interpolated and applied to the spark advance multiplier value. Next, the time since the start-to-run transfer is loaded and a time since start-to-run transfer multiplier is interpolated and applied to the spark advance multiplier value.