Apparatus and method for reducing torque fluctuation for lean burn combustion engine

摘要

An apparatus for reducing a torque fluctuation of a lean burn combustion engine (1). An injector (11) supplies fuel to combustion chambers of the engine (1). An ignitor (10, 12) ignites the fuel supplied into the combustion chambers. A knock sensor detects knocking in the engine (1). An electronic control unit (ECU) (30) computes a delay amount of the ignition timing based on a result of knock detection by the knock sensor and controls the ignitor (12) to delay the ignition timing by the delay amount to suppress knocking. The ECU (30) also detects torque fluctuation of the engine (1). The ECU (30) increases an amount of fuel injection from the injector (11) by an increase amount to reduce the torque fluctuation when the detected torque fluctuation is larger than a target value. The ECU (30) reduces the amount of exhaust gas recirculation in accordance with said computed delay amount.