Internal-combustion engines – Poppet valve operating mechanism – With means for varying timing
Patent
1998-07-16
1999-12-28
Lo, Weilun
Internal-combustion engines
Poppet valve operating mechanism
With means for varying timing
123 9016, 123 9022, F01L 1300
Patent
active
060067063
DESCRIPTION:
BRIEF SUMMARY
FIELD OF THE INVENTION
The present invention relates to a method and apparatus for controlling a valve mechanism of an engine, and more particularly to a method and apparatus for controlling a valve mechanism in which an intake valve of a diesel engine is opened or closed at a variable timing.
BACKGROUND OF THE INVENTION
Conventionally, there is known a valve driving gear, for arbitrarily and automatically controlling a valve, so as to open or close the valve at a variable timing, according to a rotary speed of an engine, with an arrangement of a hydraulic valve rush adjuster between a dynamic-system valve and a valve operating cam, for a gasoline engine for a car, for example, in Japanese Unexamined Patent Publication No. 1-232103.
A pivot portion of the valve driving gear is configured as shown in FIG. 5. In other words, there is shown a cylinder head 51, a cam 52, and an intake valve 53 (its stem portion). Between the cam 52 and the intake valve 53, there is provided a bucket 54 in a plunger insertion hole 51a, of the cylinder head 51, so as to be slidable, and a hydraulic valve rush adjuster 55 inside the bucket 54. With a rotation of the cam 52, the intake valve 53 is actuated for up-and-down strokes, through the bucket 54 and the hydraulic valve rush adjuster 55, so that the valve is opened or closed.
The hydraulic valve rush adjuster 55 forms a plunger 58 with a first adjuster portion 55A, which forms a middle-pressure chamber 56, positioned in the upper side, and two sets of adjuster members of a second adjuster portion 55B, which forms a high-pressure chamber 57, positioned in the lower side.
The first adjuster portion 55A comprises a first adjuster body 59A, a first valve spring 60, a first check ball 61, a first return spring 62, and a first check valve case 63.
The second adjuster portion 55B comprises a second adjuster body 59B, a second valve spring 64, a second check ball 65, a second return spring 66, and a second check valve case 67.
The first and second check balls 61 and 65 allow oil to flow from an oil reserve chamber 68 (described later) into the first and second adjuster bodies 59A and 59B, but do not allow it to flow out of the adjuster bodies.
The inside of the bucket 54, and a guide member 69, for guiding the above plunger 58, form the oil reserve chamber 68. This oil reserve chamber 68 has communication with an oil passage 71 of the cylinder head 51 through an oil inlet 70, provided in the side portion of the bucket 54, and has communication with the interior of the first and second adjuster bodies 59A and 59B through an oil outlet 72, provided on an inner wall of the top of the bucket 54.
Oil from the oil passage 71, of the cylinder head 51, is supplied to the oil reserve chamber 68, and then is necessarily supplied to the middle-pressure chamber 56, through the first check ball 61, from the interior of the first adjuster body 59A. The oil in the middle-pressure chamber 56 is supplied to the high-pressure chamber 57, through the second check ball 61, from the interior of the second adjuster body 59.
A volumetric rate regulation spring 73 is formed by two springs, an inner spring 74 and an outer spring 75, which have a considerably strong spring force (high hardness) relative to the first return spring 62, and is used so that a volume of the middle-pressure chamber 56 is always maintained at a fixed value, while the intake valve 53 is seated.
Next, an operation of this construction will be explained. The hydraulic valve rush adjuster 55, between the intake valve 53 and the cam 52, runs with two sets of adjuster members of the first adjuster portion 55A and the second adjuster portion 55B, which are combined to operate with each other. While an oil leak amount from the high-pressure chamber 57, of the second adjuster portion 55B, is set to a value smaller than an oil leak amount from the middle-pressure chamber 56, of the first adjuster portion 55A, a spring force of the second return spring 66, of the second adjuster portion 55B, is set to a value greater than a spring force o
REFERENCES:
patent: 4924821 (1990-05-01), Teerman
patent: 5499606 (1996-03-01), Robnett et al.
patent: 5613469 (1997-03-01), Rygiel
Komatsu Ltd.
Lo Weilun
LandOfFree
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