Electrical assistance for S.I. engine idle-speed control

This paper is concerned with an original method for spark-ignition (S.I.) e ngine idle improvement. It is well known that inappropriate idle-speed cont rol increases fuel consumption and pollutant emissions, and also compromise s stability. The solution proposed here has the distinctive feature of comb ining the traditional airflow rate control simultaneously with the usual au tomobile alternator operating as a synchronous motor, to provide a fast sup plementary torque. Experimental validation is made on a production engine. The new strategy is compared with the standard one in terms of stability, c onsumption and pollution. (C) 1998 Published by Elsevier Science Ltd. AII r ights reserved.