Coordinated Control of Air, Fuel, and Spark in an Ic-Engine

Two multivariable control schemes for a carburetted engine in a passenger car are presented. The first control scheme is applicable during the fuel turn-on phase (subsequent to a fuel turn-off period motivated by fuel economy advantages) and involves the control of the throttle and the air to fuel ratio. - The second control scheme is applicable to the closed-loop control of the idling speed and utilizes the throttle, the air to fuel ratio, and the spark timing as control variables.