KR100222721B1 - A structure for changing valve lift with engine drive condition - Google Patents

Abstract

An object of the present invention is to provide a valve mechanism that improves the engine performance by maximizing the intake and exhaust action by increasing the amount of valve lift during high-speed driving of the vehicle.

The present invention to achieve the above object

In the valve mechanism comprising a valve (1) for opening and closing the combustion chamber by axially moving along the guide of the valve guide (8) by the rotational operation of the rocker arm (2),

A cooling water passage (11) formed in the cylinder head to be connected to the water jacket for supplying cooling water circulated to cool the cylinder head in the valve stem body;

The cooling water is installed in the valve chamber 13 provided in the middle of the cooling water passage 11, and the cooling water passage 11 is opened when the oil pressure circulating the engine is high, and the cooling water passage 11 is closed when the oil pressure is low. On and off valve 15;

A guide passage formed in the valve stem body to supply the coolant introduced through the coolant passage 11 to the valve stem end portion;

A wax (6) accommodated in the space formed in the valve stem end portion and expanded or contracted by the temperature of the cooling water flowing along the guide passage;

A valve lift adjusting rod (5) projecting to the upper end of the valve stem end portion such that a lower end thereof is supported by the wax (6) and an upper end thereof is opposed to a gap adjusting screw of the rocker arm (2);

A spring (16) which elastically extends so that the valve lift adjusting rod (5) descends when the wax (6) contracts against the expansion force of the wax (6); And

It consists of a low thermal conductivity material (7) accommodated in the lower body of the valve lift adjustment rod (5) in contact with the wax (6) to block the heat of the valve (1) from being transferred to the wax (6). During high speed operation of an engine with high oil pressure, the heat of the hot coolant expands the wax 6 to push up the valve lift adjusting rod 5 to increase the lift amount of the valve 1, thereby improving the intake and exhaust performance.

Description

Valve mechanism in which the lift amount of the valve is variable in conjunction with the engine operating conditions

The present invention relates to a valve mechanism in which the lift amount of the valve is linked with the operating conditions of the engine.

In an automobile engine, an intake valve and an exhaust valve are provided in one cylinder to draw a mixer necessary for power administration into a combustion chamber and to discharge combustion gas to the outside.

Each of these intake valves and exhaust valves is operated by a valve operating mechanism so as to be opened and closed at a time designed in ignition order. The valve actuating mechanism is a mechanism that converts the rotational movement of the camshaft into the vertical movement of the valve.In the case of the overhead valve type, it consists of a valve lifter, a push rod and a rocker arm. Rotatingly supported near the center, one end is pushed up by the push rod, the opposite end presses the valve stem end to open the valve. However, since each part of the valve operating mechanism expands with the temperature rise of the engine, a valve clearance is provided to prevent gas leakage caused by the valve causing thermal expansion being supported by the rocker arm so that the valve face does not come into close contact with the valve seat. When the engine reaches operating temperature, it maintains the proper clearance.

However, when a predetermined gap is set in advance between the valve and the rocker arm as in the prior art, the valve expands and there is an advantage of preventing the leakage of gas caused by the gap between the valve face and the valve seat. As the lift amount of the valve decreases as much as it opens, the volumetric efficiency is lowered and the engine performance is lowered. In particular, it is difficult to expect a smooth intake and exhaust action at high speed.

The present invention has been proposed to solve the above problems, and has an object of increasing the volume lift by maximizing the intake and exhaust actions by increasing the amount of valve lift during high-speed driving of a vehicle.

The present invention to achieve the above object

In the valve mechanism including a valve for opening and closing the combustion chamber by moving in the axial direction along the guide of the valve guide by the rotational operation of the rocker arm,

A coolant passage formed in the cylinder head to be connected to the water jacket for supplying coolant circulating to cool the cylinder head into the valve stem body;

A valve chamber provided in the middle of the cooling water passage;

In low speed operation of the engine with low oil pressure, the through hole is blocked by the oil passage, and in the high speed operation with the high oil pressure, the protrusion rod is pushed up to be exposed in the valve chamber, and the protrusion rod is integrally formed with the protrusion rod. Cooling water opening and closing means provided with a cooling water opening and closing valve, and a spring for exerting a force in a direction in which the cooling water opening and closing valve blocks the cooling water passage;

A guide passage formed in the valve stem body to supply the coolant introduced through the coolant passage to the valve stem end portion;

A wax received in a space formed in the valve stem end portion and expanded or contracted by a temperature of cooling water flowing along the guide passage;

A valve lift adjusting rod protruding upward from the valve stem end portion such that a lower end thereof is supported by the wax and an upper end thereof is opposed to a gap adjusting screw of the rocker arm;

A spring that elastically extends the valve lift adjustment rod when the wax contracts against the expansion force of the wax; And

It is composed of a low thermal conductivity material contained in the lower body of the valve lift adjustment rod in contact with the wax to block the heat transfer of the valve to the wax, so that the heat of the hot coolant during high speed operation of the engine with high oil pressure By expanding Onus, the valve lift adjusting rod is pushed up to increase the lift amount of the valve, thereby improving intake and exhaust performance.

1 is a schematic view showing one embodiment of a valve mechanism according to the present invention

2 is a view showing the operating state of the coolant on-off valve during low speed operation of the engine

3 is a view showing the operating state of the coolant on-off valve during high speed operation of the engine

4 is an enlarged cross-sectional view of portion A of FIG.

5 is a view showing the protruding state of the valve lift adjustment rod during low speed operation of the engine

6 is a view showing the protruding state of the valve lift adjustment rod during the high speed operation of the engine

* Explanation of symbols for main parts of the drawings

1: valve 2: rocker arm

3: space 4: spring

5: valve lift adjustment rod 6: wax

7: low thermal conductivity material 8: valve guide

9: ring groove 11: coolant passage

13: valve chamber 14: oil passage

15: cooling water closing valve 16: spring

17: through hole

Hereinafter, embodiments of the present invention will be described in detail with reference to the accompanying drawings.

BRIEF DESCRIPTION OF THE DRAWINGS The figure which shows the overall shape of a valve mechanism, The code | symbol 1 shows a (intake and exhaust) valve.

The valve 1 is installed on the cylinder head (not shown) and is operated up and down by a rocker arm 2 which is operated in a seesaw operation in conjunction with a rotating camshaft so that the valve face 1a at the front end of the valve seat of the combustion chamber ( Not shown).

In the valve stem end portion 1b of the valve 1, a space 3 having an open top is formed, and a valve lift adjustment rod 5 elastically supported by a spring 4 is accommodated in the space 3. One end, i.e., the lower end, of the valve lift adjusting rod 5 is supported by the wax 6, and the other end, i.e., the upper end, protrudes from the space 3 to the upper part of the valve stem end portion 1b, and thus the rocker arm 2 At the lower end of the clearance adjusting screw (2a).

The lower end of the valve lift adjustment rod 5 has a recess structure suitable for accommodating the wax 6, which is a thermal expansion material, and has a low thermal conductivity in the lower body of the valve lift adjustment rod 5 in contact with the wax 6, for example. For example, sodium (7) is contained.

A ring-shaped groove 9 is formed inside the valve guide 8 for guiding the movement of the valve during opening and closing operation of the valve 1, and from a portion of the valve stem 1C that is opposed to the ring-shaped groove 9. A guide passage 10 having a starting inlet is in communication with the space 3 so that the coolant introduced through the guide passage 10 reaches the wax 6 to cause thermal expansion.

The ring-shaped groove 9 is formed to have a size that does not escape the inlet (10a) of the guide passage 10 during the vertical operation of the valve (1), the water jacket (not shown) of the cylinder head and the ring-shaped groove (9) A cooling water passage 11 communicating with the guide passage 10 passing through is formed in the cylinder head.

When the coolant for cooling the cylinder head flows into the guide passage 10 through the coolant passage 11 and the ring-shaped groove 9, the coolant leaks through the gap between the valve guide 8 and the valve stem 1C. O-rings 12 are provided above and below the ring-shaped grooves 9 to prevent them.

The valve chamber 13 is provided in the middle of the coolant passage 11, and the coolant opening and closing means 15, 15a, 16, and 17 are accommodated in the valve chamber 13, and the coolant opening and closing means 15, 15a, and 16 are provided. (17) includes a coolant opening / closing valve (15) for opening and closing the cooling water passage (11) by the oil pressure acting through the oil passage (14).

The coolant on / off valve 15 is normally lowered in the low / medium speed operation of the engine with low oil pressure by the elastic force of the spring 16 that springs in the direction opposite to the oil pressure. When the oil pressure is increased due to the high speed operation of the engine, the oil passage 14 is fully inserted into the oil passage 14 and the spring 16 is pushed up to the valve chamber 13 at the upper portion of the oil passage 14 while being pushed. In the raised state, the through hole 17 formed in the projection bar 15a is exposed on the cooling water passage 11 so that the cooling water in the water jacket is supplied into the valve stem 1C body.

Accordingly, the cooling water passage 11 and the oil passage 14 are formed in a direction perpendicular to each other.

The operation of the present invention will be described in detail below.

When the engine is running, the coolant injected on the water jacket and the cooling circuit circulates the cylinder block and the cylinder head by driving the coolant pump. When the engine warms up, the coolant temperature is maintained at about 80 ° C to 95 ° C.

At this time, if the driving state of the vehicle is a low speed or a medium speed, the oil pressure circulated by the oil pump is relatively lower than the high speed operation. At this time, the spring pressure is greater than the oil pressure acting on the coolant on / off valve 15 through the oil passage 14. 16, the resilient force of the 16 is so large that the protruding rod 15a is completely inserted into the oil passage 14 to block the cooling water passage 11, and the hot coolant passes through the guide passage 10 to the valve stem end portion 1b. Since it is not introduced, the wax 6 positioned at the bottom of the valve lift adjusting rod 5 is kept in a contracted state, and the valve lift adjusting rod 5 is lowered by the repulsive force of the spring 4 in the space 3 so that the gap is lowered. The clearance with the adjusting screw 2a is maintained by the distance S.

As a result, the lift amount of the valve 1 is reduced, and the distance from which the valve face 1a is separated from the valve seat is shortened, so that the amount of intake air introduced into the combustion chamber is reduced to suit the medium and low speed operating conditions of the engine.

The sodium (7) embedded in the lower end of the valve lift adjustment rod (5) surrounding the wax (6) is that the heat of the combustion chamber is transmitted to the wax (6) through the valve stem (1b) and the valve lift adjustment rod (5). By preventing the wax 6 from being thermally expanded by the heat of the valve 1 itself during low-speed operation, sodium 18 having a low thermal conductivity to the valve stem end portion 1b in order to more reliably block heat transfer May be enclosed.

However, when the engine is operated at a high speed, the oil pressure acting on the coolant on / off valve 15 is increased through the oil passage 14, and when the oil pressure is greater than the spring force of the spring 16, the coolant on / off valve 15 is opened. Since the upper side of the protruding rod 15a is exposed to the valve chamber 13 by being pushed up, the coolant passages 11 on both sides of the coolant on / off valve 15 communicate with each other through the through hole 17 formed in the protruding rod 15a. do.

Accordingly, the coolant in the water jacket reaches the wax 6 through the open coolant passage 11 and the guide passage 10, and the wax 6 causes expansion by the coolant heat of about 90 ° C. or more.

When the wax 6 expands, the valve lift adjusting rod 5 supported by the wax 6 is raised while compressing the spring 4, and an upper end thereof protrudes to the upper portion of the valve stem end portion 1b, thereby causing a gap. The clearance t with the adjustment screw 2a becomes small (see Fig. 6).

In this state, when the rocker arm 2 rotates and the clearance adjusting screw 2a pushes the valve lift adjusting rod 5 to open and close the valve 1, the valve lift amount is increased, that is, the valve face 1a is lowered. As the distance increases, the distance from the valve seat increases, so that a large amount of intake air flows into the combustion chamber or a large amount of combustion gas can be discharged quickly.

According to the present invention as described above to provide a valve lift adjustment rod which is supported by the wax, which is a thermal expansion material, and protruding height of the valve stem end portion pressed by the gap adjusting screw of the rocker arm is variable according to the degree of expansion and contraction of the wax and The valve lift adjusting rod is pushed up by the wax which has been expanded by high cooling water temperature heat during high speed operation by configuring the engine coolant to reach the wax through the valve stem body by the high oil pressure generated during the high speed driving of the vehicle. By reducing the gap, it is possible to increase the amount of valve lift to introduce a large amount of intake air into the combustion chamber or to discharge the burned gas at a time, thereby improving the engine performance by increasing the volume efficiency during high speed operation. have.

Claims (5)

In the valve mechanism including a valve for opening and closing the combustion chamber by moving in the axial direction along the guide of the valve guide by the rotational operation of the rocker arm, A coolant passage formed in the cylinder head to be connected to the water jacket for supplying coolant circulating to cool the cylinder head into the valve stem body; A valve chamber provided in the middle of the cooling water passage; In low speed operation of the engine with low oil pressure, the through hole is blocked by the oil passage, and in the high speed operation with the high oil pressure, the protrusion rod is pushed up to be exposed in the valve chamber, and the protrusion rod is integrally formed with the protrusion rod. Cooling water opening and closing means provided with a cooling water opening and closing valve, and a spring for exerting a force in a direction in which the cooling water opening and closing valve blocks the cooling water passage; A guide passage formed in the valve stem body to supply the coolant introduced through the coolant passage to the valve stem end portion; A wax received in a space formed in the valve stem end portion and expanded or contracted by a temperature of cooling water flowing along the guide passage; A valve lift adjusting rod protruding upward from the valve stem end portion such that a lower end thereof is supported by the wax and an upper end thereof is opposed to a gap adjusting screw of the rocker arm; A spring that elastically extends the valve lift adjustment rod when the wax contracts against the expansion force of the wax; And The lift amount of the valve is variable in accordance with an operating condition of the engine, characterized in that it is made of a low thermal conductivity material contained in the lower body of the valve lift adjustment rod in contact with the wax so as to block the heat of the valve from being transferred to the wax. Valve mechanism. The method of claim 1, The valve guide is formed with a ring-shaped groove in which the coolant flowing from the coolant passages stays, and the inlet of the guide passage is located in the ring-shaped groove, in which the lift amount of the valve is linked to the operating condition of the engine. Instrument. The method of claim 1, The lower end of the valve lift adjustment rod has a groove structure for accommodating the wax, the valve mechanism in which the lift amount of the valve is variable in conjunction with the operating conditions of the engine. The method of claim 1, The low thermal conductivity material is a valve mechanism in which the lift amount of the valve is variable in conjunction with the operating conditions of the engine, characterized in that the sodium. The method of claim 1, The lift amount of the valve is variable in accordance with the operating conditions of the engine, characterized in that the low thermal conductivity sodium is embedded in the valve stem end portion of the lower wax position to block the heat of the valve from conducting to the wax. Valve mechanism.

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