| 摘要 |
PROBLEM TO BE SOLVED: To make possible to prevent a situation in which effective temperature rise of a catalyst is not achieved during a temperature rise control and aggravation of drivability during a normal control. SOLUTION: The electronic control device 10 executes a temperature rise control for rising the temperature of the NOx occlusion reduction catalyst provided at an exhaust passage 7 of an engine 1 as well as executes a normal control for controlling a normal operation of the engine 1. The temperature rise control is realized by making air-fuel ratio at some of cylinders #1 to #4 of the engine 1 to be rich and making air-fuel, ration at other cylinders to be lean. On the other hand, a guard of a retardation side of injection timing is provided by using a guard value G at the time of the normal control and is provided by using guard values GR and GL at the time of the temperature rise control. The guard value G is set to be a value corresponding to a misfire limit of injection timing retardation at the time of the normal control and the guard values GR and GL are set to be a value corresponding the misfire limit of the injection timing retardation at the time of the temperature rise control. COPYRIGHT: (C)2003,JPO
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