Patent ID: 6895928
Filing Date: 2005-05-24
Classification: F02D,Y02T

Abstract:
1. A motor vehicle, comprising an internal combustion engine, an air inlet passageway in communication to aspirate the engine, an air inlet valve positioned in the passageway and being moveable to control air flow through the passageway to the engine, a valve actuator coupled for opening and closing the air inlet valve, at least one ancillary consumer unit powered by the engine, at least one engine sensor including an engine speed sensor, and an engine control unit that is operatively connected to the valve actuator, ancillary consumer unit and engine speed sensor in order to control engine operation, the engine control unit being arranged during idling of the engine: (a) to monitor the operation of the ancillary consumer unit and to calculate an engine demand depending at least partly on the operation of the ancillary unit; (b) to monitor the engine idling speed and to determine if the expected engine demand can be met at the engine idling speed; (c) and when the engine demand exceeds that available at the engine idling speed, to determine a desired degree of opening of the air inlet valve to meet the expected engine demand; wherein when the engine demand exceeds that available at the engine idling speed, the engine control unit is arranged to open the air inlet valve to a position at which the steady state airflow would exceed that necessary to meet the expected engine demand, and to calculate an exponential decay factor and then to close the air inlet valve according to the calculated decay factor towards the desired opening so that the rate at which the engine control unit doses the air inlet valve varies in proportion with the monitored engine idling speed.