Patent ID: 6837199
Filing Date: 2005-01-04
Classification: F01L,F02D,Y02T

Abstract:
1. A valve actuating apparatus for an internal combustion engine, which actuates an intake valve of the engine for opening and closing thereof, the intake valve comprising at least a first intake valve and a second intake valve, the valve actuating apparatus comprising: a camshaft that is driven for rotation in synchronism with rotation of the engine; a delayed-closing cam provided on said camshaft, for operation of the engine in a Miller cycle; a normal cam provided on said camshaft and having a cam profile for earlier valve-closing timing of the intake valve than a cam profile of said delayed-closing cam; an idling cam provided on said camshaft and having a cam profile for making the first intake valve substantially idle; a switching mechanism that switches the intake cam for opening and closing the intake valve, between said delayed-closing cam and said normal cam; operating condition-detecting means for detecting an operating condition of the engine, wherein said operation condition-detecting means includes load parameter-detecting means for detecting a load parameter indicative of a load on the engine; and switching mechanism control means for controlling said switching mechanism such that when the detected operating condition of the engine indicates starting or idling of the engine, the intake valve is opened and closed by said normal cam, and when the detected operating condition of the engine is a predetermined operating condition indicating other than the starting and idling of the engine, the intake valve is opened and closed by said delayed-closing cam, wherein the predetermined operating condition of the engine includes a condition of the load parameter detected by said load parameter-detecting means being smaller than a first predetermined value, and wherein said switching mechanism control means controls said switching mechanism such that when the load parameter is smaller than a second predetermined value which is smaller than the first predetermined value, the first intake value is made substantially idle by said idling cam, and the second intake valve is opened and closed by said delayed-closing cam, and when the load parameter is equal to or larger than the second predetermined value and smaller than the first predetermined value, the first intake valve and the second intake valve are opened and closed by said delayed-closing cam.