Patent Application
20080083386
Hereinafter, preferred embodiments of the present invention will be described in detail with reference to the attached drawings.
In some embodiments, a variable valve lift follower includes three cams for each valve to control the opening amounts of the valve based on engine conditions by the rotational force of a cam assembly. A middle low lift cam 10 and two high lift cams 11 are disposed in a row.
A knock pin, formed on the top of the valve contact portion 51 positioned opposite to the HLA 23, moves in the longitudinal direction to connect an inner body 54 and an outer body 55 with each other, thus applying a high lift thereto.
An HLA contact portion 50 supplying oil to the inner body 54 is provided on the bottom of one side of the inner body 54, a valve contact portion 51 is provided on the bottom of the other side of the inner body 54, and the knock pin is installed on the top of the valve contact portion 51.
The knock pin is installed on the other end of the inner body 54 so as to move in the forward and backward directions (based on the longitudinal direction of the outer body) by the oil pressure, and a hinge pin 56 is disposed on one end of the inner body 54, through which the outer body 55 and the end portion of the inner body 54 are hinge-connected with each other, thus allowing the other end portion of the outer body 55 to rotate independently.
Since the knock pin is moved by the oil pressure, the oil path 52 is provided to connect the HLA contact portion 50 with a cylinder 53 including the knock pin, thus supplying oil introduced through the HLA contact portion 50 to the knock pin.
The oil path 52 comprises a first connection path 52a connected with the HLA contact portion 50, a second connection path 52b formed in the horizontal direction and fluidly connected to the first connection path 52a, and a third connection path 52c coupling the second connection path 52b to the cylinder 53.
The first and third connection paths 52a and 52c are inclined. The paths 52a and 52c can be inclined at various angles to avoid interference with peripheral parts. An oil supply hole 57 extending to the outside is disposed on an end of the second connection path 52b and a cap is attached detachably onto the oil supply hole 57.
Operation of the variable valve lift follower in accordance with an embodiment of the present invention will now be described.
(1) When applying high lift: the oil is introduced to the inner body 54 through the HLA contact portion 50 in the period of high speed of full load, supplied from the HLA contact portion 50 to the first connection path 52a of the oil path, and moved to the second and third connection path 52b and 52c, thus transmitting the oil pressure to the knock pin in the cylinder 53.
Subsequently, the knock pin is pushed out from the inner body 54 by the oil pressure and the rotational forces of the high lift cams 11 are transmitted to the knock pin when the other end portion rotates downward, thus becoming in a high lift state.
(2) When applying low lift: as the oil charged in the cylinder is exhausted in the period of low speed of part load, the knock pin is returned to the inside of the inner body 54 and, as the oil moves from the oil path 52 to the HLA contact portion 50 and is discharged to the HLA 23, the outer body 55 and the inner body 54 are separated from each other to rotate independently. The valve is operated only by the inner body 54, thus becoming in a low lift state.
The present invention can reduce stress and friction caught by the valve spring to enhance the fuel efficiency and the engine performance by providing a knock pin connecting the outer body 55 with the inner body 54 on the top of the valve contact portion. The oil path 52, through which the oil is received from the HLA 23 transmits the oil pressure to the knock pin.
As described above, according the variable valve lift follower in accordance with the present invention, it is possible to reduce the effective mass of the valves and decrease the stress and friction on the valve spring, thus enhancing the fuel efficiency and the engine performance, by providing the knock pin connecting the outer body with the inner body on the top of the valve contact portion and by forming the oil path, through which the oil is received from the HLA and the oil pressure is transmitted to the knock pin.
While this invention has been described in connection with what is presently considered to be practical exemplary embodiments, it is to be understood that the invention is not limited to the disclosed embodiments, but, on the contrary, is intended to cover various modifications and equivalent arrangements included within the spirit and scope of the appended claims.
| Number | Date | Country | Kind |
|---|---|---|---|
| 10-2006-0098272 | Oct 2006 | KR | national |
