초록 ▼

An engine variable valve timing mechanism is controlled during engine starting to set valve opening overlap of intake and exhaust valves around 30.degree. CA. In this case, internal EGR is actively conducted, fuel burning velocity within a cylinder becomes relatively slow and unburned fuel within th

An engine variable valve timing mechanism is controlled during engine starting to set valve opening overlap of intake and exhaust valves around 30.degree. CA. In this case, internal EGR is actively conducted, fuel burning velocity within a cylinder becomes relatively slow and unburned fuel within the cylinder is emitted to an exhaust pipe to be post-burned. The temperature of exhaust gas is maintained high and catalyst converters in the cold state may be activated quickly by actively implementing such post-burning within the exhaust pipe. Further, ignition timing is retarded, the air-fuel ratio is controlled to a slightly lean ratio and the exhaust valve is advanced. The effect of raising the temperature of exhaust gas by post-burning may be realized more reliably by combining each of these controls.

대표청구항

[ What is claimed is:] [6.]6. A control system as in claim 5 wherein the plurality of ignition operation are effected while maintaining retarded ignition timing.

[ What is claimed is:] [6.]6. A control system as in claim 5 wherein the plurality of ignition operation are effected while maintaining retarded ignition timing.