| 摘要 |
PROBLEM TO BE SOLVED: To provide a combustion control device for an engine which properly controls an air/fuel ratio in an exhaust gas flowing into a catalyst, materializes stabilized combustion in fast idle and can avoid the occurrence of knocking in a low speed heavy load operation or in WOT (Wide Open Throttle).SOLUTION: An ECU 26 controls the phase of a sub cam 20 and causes an exhaust valve 7 to open in a predetermined timing through an intake stroke into a compression stroke to discharge a part of in-cylinder air to an exhaust system. After the exhaust valve 7 is closed, the ECU 26 causes an injector 11 for in-cylinder direct injection to inject fuel. Since the injection of the fuel from the injector 11 is carried out after the exhaust valve 7 is closed, the fuel does not blow through the exhaust system, the in-cylinder air/fuel-ratio becomes rich and the occurrence of the knocking is avoided. The exhaust gas is mixed with the discharged air when passing through the exhaust system to have the air/fuel ratio corresponding to the cleaning capacity of a catalyst 14. |
