To provide a multi-cylinder four-cycle engine with an internal EGR system capable of avoiding a loss of the strength of an engine and the deterioration of the durability of the engine while exhibiting an NOx reducing effect by preventing an excessive intake air temperature rise and an excessive exhaust gas temperature rise during internal EGR which are caused by the generation of high and low intake air temperatures by a cylinder.
A multi-cylinder four-cycle engine with an intercooler is configured to perform internal EGR for an intake valve that performs the minimum sub-lifting of the intake valve during an exhaust stroke and internal EGR for an exhaust valve that performs the minimum sub-lifting of the exhaust valve during an intake stroke. The cam profile of an exhaust cam of a first cylinder group among multiple cylinders is set to an EGR cam profile of the exhaust valve that performs internal EGR for the exhaust valve, and the cam profile of the intake cam of a second cylinder group except for the first cylinder group is set to an EGR cam profile of the intake valve that performs internal EGR for the intake valve.
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Masahisa Takahashi
Hiroshi Matsumoto