JPS60243312A - Variable opening amount of valve device for four-stroke cycle engine - Google Patents

Abstract

PURPOSE:To obtain a balanced high output by a structure in which an intake or exhaust valve is opened by pushing down the upper surface of a hydraulic tappet by the rotation of a cam, in which a relief orifice is provided in the high pressure chamber of the hydraulic tappet so that the valve lift may be changed between a high speed and a low speed ranges. CONSTITUTION:In a high engine speed range, the oil pressure entering from an oil passage 12 into a low pressure chamber 13 enters a high pressure chamber 14 via a check valve 11 to expand a space between an outer cup 8 and an inner cup 9 to maintain no clearance between an intake or exhaust valve 1 and a cam 5. Therefore, as the cam 5 rotates, the valve 1 is pushed down via a hydraulic tappet 3 as dictated by the profile of the cam 5. On the other hand, as a relief valve 16 is opened in a low speed range, the oil pressure in the high pressure chamber 14 escapes gradually through an orifice 17 by the downward force of the cam 5. As a result, the outer cup 8 moves upward, and the opening amount of the valve 1 is correspondingly reduced and the opening duration is also reduced.

Description

DETAILED DESCRIPTION OF THE INVENTION [Technical Field of the Invention] The present invention relates to a variable valve opening amount device for a four-stroke engine using hydraulic tappets.

Technical background of the invention and its problems] A four-stroke engine uses umbrella-shaped valves for intake and exhaust.

The valve is biased in the closing direction by a spring, and is pushed down and opened by the rotation of a cam on a camshaft that is linked to the crankshaft. Therefore, the opening amount and opening/closing timing of the valve are determined by the shape of the cam. In high-speed, high-output engines, the valves are opened wide and open for a long time to reduce resistance to intake and exhaust flow, improve intake and exhaust efficiency, and increase output. However, in such an engine, at low speeds, there is a lot of intake air blow-through and the intake air flow rate is slow, so the combustion efficiency cannot be improved due to the vortex flow, and the output decreases.
There are disadvantages such as increased fuel consumption.

[Purpose of the invention]

This invention utilizes a hydraulic tappet that maintains the gap between the valve and the cam to zero, and changes the amount of valve opening in the low and high speed ranges, making it possible to obtain balanced high output at both high and low speeds. The purpose of this invention is to obtain a variable valve opening amount device.

[Structure of the invention]

Embodiments of the present invention shown in the drawings will be described below.

An umbrella-shaped intake or exhaust valve 1 is biased in the closing direction by a valve spring 2. At the top of valve 1,
A hydraulic tappet 3 is mounted.

The camshaft 4 rotates in conjunction with the crankshaft, and the rotation of the cam 5 pushes down the valve 1 via the hydraulic tappet 3 against the valve spring 2 to open it. In the hydraulic tappet 3, an outer cylinder 6 is slidably inserted into a cylinder head 7, an outer cup 8 and an inner cup 9 are slidably inserted inside, and are urged to spread by a spring 10. A check valve 11 is provided so that the lower surface of the outer cup 8 is in contact with the upper end of the valve 1. The hydraulic pressure in the hydraulic passage 12 enters the low pressure chamber 13 in the outer cylinder 6 through the side hole, further flows into the inner cup 9, passes through the check valve 11, and enters the high pressure chamber 14 in the outer cup 8. ing. The high pressure chamber 14 communicates with a relief valve 16 through a relief hole 15 . The relief valve 16 is provided with a throttle hole 17 and can be opened and closed by rotating it, and is opened and closed by a step motor or an electromagnetic piece depending on the engine speed, and closes at high speeds and closes at low speeds. It is designed to open with .

Therefore, in the high speed range, the hydraulic pressure entering the low pressure chamber 13 from the hydraulic passage 12 passes through the check valve 11 and enters the high pressure chamber 14.
Go inside, expand outer cup 8 and inner cup 9, and open valve 1.
The hydraulic pressure in the high pressure chamber 14, which keeps the gap between the cam 5 and the cam 5 at zero, is sealed by the check valve 11 and does not escape. When the cam 5 rotates, the rotation pushes down the valve 1 via the hydraulic tappet 3, so the opening amount and opening/closing timing of the valve 1 are in accordance with the profile of the cam 5, and are set as shown in Fig. 2 (A> line). It becomes like this.

On the other hand, in a low speed range, the relief valve 16 is opened by the rotation sensor. Therefore, the hydraulic pressure in the high pressure chamber 14 gradually escapes through the throttle hole 17 of the relief valve 16 due to the application of the downward force of the cam 5, so the outer cup 8 rises and the valve 1 is opened by that amount. becomes less. That is, as shown in FIG. 2 (B), the amount by which the valve 1 opens becomes smaller and the timing at which it opens becomes shorter.

As a result, the flow rate of intake air increases, the number of blowouts decreases, and the vortex flow increases combustion efficiency, increasing output in the low-speed range.

〔Effect of the invention〕

As explained above, the present invention provides a check valve in which a hydraulic tappet is provided at the upper end of an umbrella-shaped valve, and the upper surface of the hydraulic tappet is pushed down by the rotation of the cam of the camshaft to open the valve. A relief hole is provided in the high pressure chamber of the hydraulic tappet that is closed, and a relief valve is connected to the relief hole so that the relief valve opens in the low speed range, so that part of the hydraulic pressure in the high pressure chamber is released in the low speed range and the valve is closed. The amount of opening can be reduced, the output can be increased by increasing the flow velocity, and a balanced high output can be obtained from low speed to high speed. And since it uses hydraulic tappets, it can be done at low cost. In addition, in a four-valve engine in which one cylinder has two intake valves and two exhaust valves, it may be installed on one intake valve and one exhaust valve.

[Brief explanation of the drawing]

FIG. 1 is a longitudinal sectional view showing an embodiment of the present invention, and FIG. 2 is a diagram showing changes in valve opening. 1...Valve, 3...Hydraulic tappet, 4...Camshaft, 5...Cam, 11...Check valve,
14... High pressure chamber, 15... Relief hole, 16...
Relief valve. Applicant's agent Kiyotomi Inomata 1 Suyomi 2 Kurarev angle - Procedure Neichi ILF, 83 April 1985 // Commissioner of the Patent Office Manabu Shiga 1 Indication of the case 1980 Patent application No. 100014 2 Invention Name 4 Recycle engine valve listener n1 Variable device 3 Person making the amendment Relationship to the case Patent applicant (208> Suzuki Automobile Industry Co., Ltd. 4 Agent 7 Subject of amendment ---□. Drawing 8 Amendment In the contents drawing, a leader line numbered 8 is added as shown in red in the attached drawing.

Claims (1)

[Claims] A hydraulic tappet is provided at the upper end of the umbrella-shaped valve, and the valve is opened by pushing down the upper surface of the hydraulic tappet with the rotation of the cam of the camshaft.A relief hole is provided in the high pressure chamber of the hydraulic tappet that is closed by the check valve. 1. A variable valve opening amount device for a four-cycle engine, characterized in that a relief valve is connected to the relief hole to open the relief valve in a low speed range.