| 摘要 |
PROBLEM TO BE SOLVED: To improve accelerating performance while reducing NOx exhaust amount from an engine when, for example, the engine is shifted from a regular operation state to an accelerating operation state, in such case that a lean NOx catalyst is arranged on the exhaust passage of a direct injection type diesel engine and also one part of exhaust is returned to an intake passage by EGR passage and its flow rate is regulated by the EGR valve. SOLUTION: When an engine is shifted to an accelerating operation state by a big change of an accelerator opening, at first, by dividing fuel into three and jetting it near the compression upper dead point of a cylinder and increasing a non-injection interval Δt as a reducing agent component increase control, CO, HC density in the exhaust is increased and the operation of the catalytic conversion is improved. At the same time, by reducing and correcting a target exhaust return rate EGRt by a set value αand reducing the real exhaust return rate extremely, the suction amount of a new air is increased quickly. Then, the fuel injection amount is increased more largely than usual and the accelerating performance of the engine as well as the increase of the new air are improved. |
