| 摘要 |
PROBLEM TO BE SOLVED: To provide a four-cycle engine provided with an internal EGR system by which the amount of evolution of NOx (nitrogen oxide) is controlled to an appropriate value without incurring a performance penalty to the engine by causing the amount of the internal EGR and its timing to correspond with conditions of engine-operation, and the state of opening of an exhaust valve. SOLUTION: In the four-cycle engine provided with an internal EGR system, the exhaust valve is constituted to be opened in two lift-patterns of a main-lift including full-opening of the exhaust valve and a sub-lift which is started later than opening of an intake valve, and is smaller than the main-lift. An exhaust control valve is placed in the exhaust path to open/close the exhaust path to change the area of the exhaust-path at the time of operation of the sub-lift. The exhaust control valve is opened/closed at the sub-lift time, thus to regulate the amount of recirculation of exhaust gas (amount of EGR) which is sent from the exhaust-gas path into a combustion chamber. COPYRIGHT: (C)2006,JPO&NCIPI
|
