| 摘要 |
PROBLEM TO BE SOLVED: To quickly activate a catalyst device by increasing exhaust gas temperature at cold engine and secure an acceleration responsiveness from an idling condition. SOLUTION: Variable valve trains capable of variably controlling lift/operating angle and center angle are provided on both of an intake valve and an exhaust valve of an internal combustion engine. The lift/operating angle of the exhaust valve gets small and exhaust valve open timing is retarded after bottom dead center as characteristics 104, 105 at the time of cold engine as compared with characteristics 101 after warming up in idling. Consequently, exhaust gas is compressed in a cylinder to raise temperature and increase pumping loss. The intake valve gets characteristics to increase engine load at cold engine. Lift characteristics of the exhaust valve is preferentially variably controlled like the characteristics 104→the characteristics 102 at a time of acceleration from the cold engine condition. COPYRIGHT: (C)2006,JPO&NCIPI
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