KR101080779B1 - 2 Sstep Variable Valve Lift System - Google Patents

Abstract

The present invention relates to a two-stage variable valve lift device for an internal combustion engine, and more particularly, to enable the pivot center of the rocker arm to be changed in two stages, thereby realizing a high valve lift and a low valve lift according to the engine speed. A two stage variable valve lift apparatus for an internal combustion engine.

To this end, the present invention is a roller contacting the cam is rotatably attached to the front end, the rear end and the rocker arm is connected to the upper end of the valve; A first mounting hole formed at a pivot position of the rocker arm; A pair of guides arranged adjacent to both sides of the rocker arm and bolted to the cylinder head, and having a second mounting hole formed at each inner surface thereof; A connecting member, a high valve lift pivot shaft integrally formed at one front end of the connecting member and inserted into the first mounting hole of the rocker arm, and integrally formed at a rear end of the opposite side of the connecting member. A pair of rocker shaft mechanisms composed of a low valve lift pivot shaft inserted into the second mounting hole of the second mounting hole; It is inserted into the first mounting hole, provides a two-stage variable valve lift device for an internal combustion engine comprising a spring positioned between the high valve lift pivot shaft of the pair of rocker shaft mechanism.

2-stage variable valve lift, rocker shaft mechanism, pivot shaft, guide, rocker arm

Description

Two-stage variable valve lift system for internal combustion engine {2 Sstep Variable Valve Lift System}

1 is a cross-sectional view showing a two-stage variable valve lift apparatus for an internal combustion engine according to the present invention.

Figure 2 is a front view and a plan view showing a rocker arm structure applied to a two-stage variable valve lift apparatus for an internal combustion engine according to the present invention.

3 is a front view and a plan view showing a rocker shaft mechanism whose pivot center is mounted on a rocker arm of a two-stage variable valve lift apparatus for an internal combustion engine according to the present invention;

4 and 5 are plan views showing a rocker shaft mechanism assembled between the rocker arm and the guide mounted on the cylinder head of the two-stage variable valve lift apparatus for an internal combustion engine according to the present invention. 5 is a plan view showing an operating state, and FIG. 5 is a plan view showing an operating state for implementing a low valve lift.

6 is a conceptual diagram of a hydraulic circuit for supplying oil to an oil supply hole formed in a guide of a two-stage variable valve lift apparatus for an internal combustion engine according to the present invention;

7 is a cross-sectional view showing a state in which a high valve lift of the two-stage variable valve lift apparatus for an internal combustion engine according to the present invention is implemented.

8 is a cross-sectional view showing a state in which a low valve lift of the two-stage variable valve lift apparatus for an internal combustion engine according to the present invention is implemented.

9 is a cross-sectional view showing a valve opening and closing mechanism of a general engine having a roller rocker arm.

<Explanation of symbols for the main parts of the drawings>

10: rocker arm 12: first mounting hole

14: first groove 16: pivot valve for high valve lift

18: Pivot Shaft for Low Valve Lift

20 connection member 22 rocker shaft mechanism

24: guide 26: second mounting hole

28: second groove 30: spring

32: oil supply hole 34: oil distribution line

36: oil supply line 38: oil supply valve

40: cam 42: roller

44: valve 46: valve spring

48: rocker arm shaft 50: combustion chamber

The present invention relates to a two-stage variable valve lift device for an internal combustion engine, and more particularly, to enable the pivot center of the rocker arm to be changed in two stages, thereby realizing a high valve lift and a low valve lift according to the engine speed. A two stage variable valve lift apparatus for an internal combustion engine.

Generally, the internal combustion engine burns air and fuel sucked through an intake valve to obtain power, discharges combustion gas through an exhaust valve, and then immediately inhales new air and fuel through the intake valve.

That is, the function of the intake and exhaust valve in the gasoline engine is to control the flow of intake and exhaust in the cylinder, and to maintain the airtight in the cylinder.In the compression stroke and the explosion stroke, both the intake and exhaust valves are closed to maintain the airtight in the cylinder. In the stroke and exhaust stroke, only the intake valve or exhaust valve is opened, respectively, so that the intake of fuel gas and the discharge of combustion gas are performed.

The opening and closing of the valve is performed by the cam formed on the camshaft pushing the end of the valve, and the camshaft is rotated by receiving the driving force of the crankshaft through a timing belt or a chain. The contact surface is formed in an arc shape with less abrasion.

Normally, in the engine, the intake valve and the exhaust valve are opened and closed by a cam, the timing of opening and closing the valve and the amount of opening are determined by the shape of the cam.

In addition, since the camshaft is driven by the crankshaft, the valve is opened and closed at a certain point of time based on the crank angle, and the section in which the valve is open is also constant based on the crank angle.

That is, the valve is opened and closed at a predetermined time based on the crank angle, which has a fixed value for each engine and has a constant value regardless of the engine speed and the load.

However, since the valve open time (actual time, not crank angle) decreases in inverse proportion to the engine speed, it is difficult to smoothly supply air into the cylinder at high speed due to the inertia effect of the air.

Conventional valve opening and closing mechanism is to open and close the valve is always a constant lift by a cam having a constant profile, the rocker arm type valve lift as shown in Figure 9 attached to the rotational movement of the camshaft Accordingly, the rocker arm 10 making contact with the cam 40 is configured to open and close the valve 44 while rotating around the rocker arm shaft 50.

In FIG. 1, reference numeral 42 is a roller hinged to one end of the rocker arm 3 to make contact with the cam 40, and reference numeral 46 is a valve spring for opening and closing the valve 44. 50 indicates each combustion chamber.

Therefore, when the cam 40 rotates to push up the roller 42, the rocker arm 10 rotates to pivot down the valve 44 by pivoting the rocker arm shaft 48, and the cam 40 further depresses. In a section in which the roller 42 is not pushed up, the restoring force of the valve spring 46 acts to push up the valve 44. The rocker arm 10 pivots the rocker arm shaft 48 by pivoting the cam. 40 and the roller 42 are in close contact with each other.

At this time, the valve lift is determined by the maximum height of the cam, the center of the cam shaft, the rocker shaft center, the distance between the valve guide bar, but in the conventional engine, the height of the cam and the distance between the parts are fixed, so the valve lift is constant Has

That is, in the conventional valve lift apparatus as described above, since the opening / closing time of the intake / exhaust valve is always fixed at a constant state, it is not possible to control the amount of intake or exhaust air, and thus is required throughout the operating region of the engine. There was a problem that can not implement the optimal state.

That is, when the intake / exhaust valve is set on the basis of the high speed operating region, there is a problem that the engine does not exhibit optimal performance in the low speed operating region.

To overcome this problem, the industry is actively applying variable valve mechanisms, such as Honda's VTEC, Toyota's VVTL-i, Mitsubishi's MIVEC, BMW's Valvetronic and Porsche's Vario system.

The Honda, Toyota, and Mitsubishi systems are made of dual cams, and the cams are switched between the two cams using hydraulic mechanisms while applying different cam profiles at high speeds and low speeds. The system consists of a high speed cam and switches between the low speed cam and the high speed cam by using a double tappet. BMW's Valvetronic is a device that can continuously change the valve lift and the valve opening section. It consists of a cam.

In addition, the present applicant is a continuous variable valve lift control mechanism, which is capable of varying the lift amount of a valve in accordance with the operation state of an engine (a domestic variable valve lift apparatus (Domestic Application No .: 10-2003-0069567 (2003.10.07)). Has already been filed.

The present invention is configured in such a way that the intake valve lift of the engine can be changed in two stages according to the number of revolutions of the engine in consideration of the above problems of the general valve lift apparatus. By making it possible to achieve high valve lift and low valve lift according to the engine speed, the two-stage variable valve lift device for an internal combustion engine can be improved to maximize the efficiency of the engine and improve fuel efficiency and output. Its purpose is to.

The present invention for achieving the above object in the valve lift apparatus for the engine,

A roller contacting the cam is rotatably attached to the front end, and a rear end of the rocker arm connected to the upper end of the valve; A first mounting hole formed at a pivot position of the rocker arm; A pair of guides arranged adjacent to both sides of the rocker arm and bolted to the cylinder head, and having a second mounting hole formed at each inner surface thereof; A connecting member, a high valve lift pivot shaft integrally formed at one front end of the connecting member and inserted into the first mounting hole of the rocker arm, and integrally formed at a rear end of the opposite side of the connecting member. A pair of rocker shaft mechanisms composed of a low valve lift pivot shaft inserted into the second mounting hole of the second mounting hole; It is inserted into the first mounting hole, and provides a two-stage variable valve lift device for an internal combustion engine comprising a spring positioned between the high valve lift pivot shaft of the pair of rocker shaft mechanism.

In a preferred embodiment, a first groove is formed in which the connecting member can be inserted from the outer circumferential surface of the first mounting hole of the rocker arm to the rear end thereof, and the front side of the pair of guides from the outer circumferential surface of the second mounting hole of the pair of guides is formed. A second groove may be formed in which the connection member may be inserted.

In particular, the hydraulic supply means is connected to the pair of guides so that the low valve lift pivot shaft inserted into the second mounting hole can be pushed with oil pressure.

The oil supply means includes an oil supply hole processed to communicate with a second mounting hole at a predetermined position of each guide, an oil distribution line connected to each oil supply hole, and a cylinder head to supply oil to the oil distribution line. An oil supply line connected to the gallery and an oil supply valve attached to the oil supply line are featured.

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

1 is a cross-sectional view showing a two-stage variable valve lift apparatus for an internal combustion engine according to the present invention, Figure 2 is a front view and a plan view showing a rocker arm structure applied to a two-stage variable valve lift apparatus for an internal combustion engine according to the present invention, 3 is a three-sided view showing a rocker shaft mechanism whose pivot center is mounted on the rocker arm of the two-stage variable valve lift apparatus for an internal combustion engine according to the present invention.

According to the present invention, the roller contacting the cam is rotatably attached to the front end, and the rear end of the rocker arm pivot structure is connected to the upper end of the valve in two stages. One point is to make the lift possible.

That is, the present invention provides a structure for changing the position of the rocker shaft mechanism without changing the cam height in the engine, changing the distance between the cam axis center and the pivot, the pivot and the valve guide and thereby the valve lift.

Referring to FIG. 2, which shows the rocker arm structure of the present invention, a first mounting hole 12 is formed through a pivot position of the rocker arm 10, and an outer peripheral portion of the first mounting hole 12 is formed. The first groove 14 having a shape extending toward the rear end of the rocker arm 10 is recessed.

In more detail, the first groove 14 is processed into a groove having a shape that gradually narrows from the outer circumference of the first mounting hole 12 to the rear end of the rocker arm 10.

Referring to FIG. 3, which shows the rocker shaft mechanism 22 inserted into the first mounting hole 12 and the first groove 14, the rocker shaft mechanism 22 is provided with a cam when viewed from the front. It is formed in the same shape, the configuration is composed of a high valve lift pivot shaft 16, a low valve lift pivot shaft 18, and a connecting member 20 connecting them.

That is, the connecting member 20 is a cam-shaped plate body that narrows from one side to the other, the front end of the connecting member 20 in the first mounting hole 12 of the rocker arm 10 The high valve lift pivot shaft 16 to be inserted is formed to protrude integrally, and the low valve lift inserted into the second mounting hole 26 of the guide 24 described later is formed at the rear end of the opposite side of the connecting member 20. The pivot axis 18 protrudes.

Of course, in accordance with the cam shape of the connecting member 20, the diameter of the high valve lift pivot shaft 16 is formed larger than the diameter of the low valve lift pivot shaft 18.

Here, looking at the assembly state of the guide structure and the rocker arm shaft mechanism mounted adjacent to both sides of the rocker arm as follows.

4 and 5 are plan views showing the rocker shaft mechanism assembled between the rocker arm and the guide mounted on the cylinder head of the two-stage variable valve lift apparatus for an internal combustion engine according to the present invention. 5 is a plan view illustrating an operating state to be implemented, and FIG. 5 is a plan view illustrating an operating state to implement a low valve lift.

A pair of guides 24 formed in a rectangular block shape are arranged adjacent to both sides of the rocker arm 10, and the front and rear ends thereof are mounted to the cylinder head by bolting. An inner surface of each guide 24 (the rocker) The second mounting hole 26 is recessed in the surface of the shaft mechanism 22 that coincides with the lower valve lift pivot shaft 18.

In addition, a second groove 28 into which the connecting member 20 can be inserted is further concave from the outer circumferential surface of the second mounting hole 26 of the pair of guides 24.

Accordingly, the high valve lift pivot shaft 16 of the pair of rocker shaft mechanisms 22 is inserted through the first mounting hole 12 of the rocker arm 10 while the low valve lift pivot shaft ( The assembly of the rocker shaft mechanism 22 is completed by inserting 18 through the second mounting hole 26 of the guide 24.

At this time, a spring 30 is inserted into the first mounting hole 12, and the spring 30 can be compressed between the high valve lift pivot shafts 16 of the rocker shaft mechanism 22. Is located.

On the other hand, at a predetermined position of the guide 24, an oil supply hole 32 capable of providing oil pressure to the second mounting hole 26 therein is formed.

Here, a description will be given of the hydraulic pressure providing means for providing the hydraulic pressure to the oil supply hole.

6 is a conceptual diagram of a hydraulic circuit for supplying oil to an oil supply hole formed in a guide of a two-stage variable valve lift apparatus for an internal combustion engine according to the present invention.

A hydraulic pressure providing means is connected to the pair of guides 24 so as to push the low valve lift pivot shaft 18 inserted into the second mounting hole 26 with oil pressure. An oil supply hole 32 processed in communication with the second mounting hole 26 at a predetermined position of each guide 24, an oil distribution line 34 connected to each oil supply hole 32, and the oil distribution An oil supply line 36 connected to a cylinder head gallery (not shown) and oil supply valve 38 attached to the oil supply line 36 to supply oil to the line 34.

At this time, the oil supply valve 38 is connected to the engine ECU so as to exchange electrical signals, it is opened and closed in accordance with the signal of the engine ECU.

The operation state of the two-stage variable valve lift apparatus of the present invention having the configuration as described above will be described.

4 and 7 are views showing a state in which a high valve lift is implemented in a two-stage variable valve lift apparatus for an internal combustion engine according to the present invention, and FIGS. 5 and 8 are sectional views showing a state in which a low valve lift is implemented. .

High valve lift implementation behavior

As shown in FIG. 4 and FIG. 7, in the high speed operation section of the engine, the engine ECU sends a closing signal to the oil supply valve 38 so that oil pressure is not supplied to the oil supply hole 32 of the guide 24. It does not become a state.

In this state, the spring 30 located inside the first mounting hole 12 of the rocker arm 10 is in a state in which the rocker shaft mechanism 22 is pushed out.

That is, the high valve lift pivot shaft 16 of the rocker shaft mechanism 22 is inserted into the first mounting hole 12 of the rocker arm 10, and at the same time, the low valve lift pivot shaft 18. ) Is inserted into the second mounting hole 26 of the guide 24, and the connecting member 20 is inserted into the second groove 28 of the guide 24.

Thus, the rocker arm 10 is angular movement around the high valve lift pivot axis (16).

That is, when the cam 40 rotates together with the engine driving to push up the roller 42 of the rocker arm 10, the rocker arm 10 rotates about the high valve lift pivot shaft 16. By the action, the valve 44 coupled to the rear end of the rocker arm 10 is pushed down to the open state of the valve 44.

On the other hand, in the section in which the cam 40 is further rotated so as not to push up the roller 42, the valve spring 46 acts to push up the valve 44, and the valve 46 returns to its original position and is closed. do.

By such a high valve lift pivot shaft 16 it is possible to increase the valve lift at high engine speed, thereby reducing the intake flow resistance and improving the engine fuel economy.

Low Valve Lift Implementation Behavior

5 and 8 illustrating an implementation of a low valve lift, the engine ECU sends a signal to the oil supply valve 38 in the low speed operation section of the engine so that the oil is opened. The oil supply line 36 and the oil distribution line 34 are supplied from the gallery to the oil supply hole 32 of the guide 24.

Accordingly, the low valve lift pivot shaft 18 inserted into the second mounting hole 26 is pushed out by the oil pressure provided to the oil supply hole 32 of the guide 24. 20 is also pushed out of the second groove 28 of the guide 24.

At the same time, the high valve lift pivot shaft 16 is pushed further into the first mounting hole 12 of the rocker arm 10 and, of course, the connecting member 20 also has a first groove of the rocker arm 10. 14, the spring 30 in the first mounting hole 12 of the rocker arm 10 is compressed by each of the high valve lift pivot shafts 16 that have been pushed in.

Accordingly, the rocker arm 10 is angularly moved about the low valve lift pivot shaft 18.

That is, when the cam 40 rotates together with the engine driving to push up the roller 42 of the rocker arm 10, the rocker arm 10 rotates about the low valve lift pivot shaft 18. By the action, the valve 44 coupled to the rear end of the rocker arm 10 is pushed down, and the valve is opened.

On the other hand, in the section where the cam 40 is further rotated so as not to push up the roller 42, the valve spring 46 acts to push up the valve 44, and eventually the valve returns to its original position and closes.

By such a low valve lift pivot shaft 18, the valve lift can be reduced at low engine speed, and the remaining exhaust gas can be sufficiently removed to ensure combustion stability.

In this way, the pivot position of the rocker arm 10 is varied in two stages with respect to the high valve lift pivot shaft 16 or the low valve lift pivot shaft 18 according to the engine speed. The valve lift is thus easily adjusted, consequently contributing to improved engine fuel economy.

As described above, according to the two-stage variable valve lift apparatus for an internal combustion engine according to the present invention, the intake valve lift of the engine can be varied in two stages according to the number of revolutions of the engine, thereby obtaining the following effects.

1) In the high-speed operation section of the engine, the valve lift can be increased to reduce the intake flow resistance, thereby increasing the engine power and reducing the pumping loss, thereby improving the engine fuel efficiency.

2) In the low lift section, the spring is reduced because the amount of valve spring is small. Since the valve spring load is proportional to the camshaft drive torque, the camshaft drive force can be reduced by reducing the spring load, thereby improving the engine fuel economy.

3) In the low-speed running section of the engine, residual exhaust gas is sufficiently removed to ensure combustion stability, thereby lowering the idling speed, which may help to improve engine fuel efficiency.

Claims (3)

In the valve lift device for the engine, A rocker arm having a roller in contact with the cam rotatably attached to the front end, connected to the upper end of the valve at the rear end thereof, and having a first mounting hole for pivoting therein; A pair of guides arranged adjacent to both sides of the rocker arm and bolted to the cylinder head, and having a second mounting hole formed at each inner surface thereof; A connecting member, a high valve lift pivot shaft integrally formed at one front end of the connecting member and inserted into the first mounting hole of the rocker arm, and integrally formed at a rear end of the opposite side of the connecting member. A pair of rocker shaft mechanisms composed of a low valve lift pivot shaft inserted into the second mounting hole of the second mounting hole; A spring inserted into the first mounting hole and positioned between the high valve lift pivot shafts of the pair of rocker shaft mechanisms; And a hydraulic providing means connected to the pair of guides so as to push the low valve lift pivot shaft inserted into the second mounting hole with oil pressure. The method of claim 1, wherein the first groove in which the connecting member can be inserted from the outer circumferential surface of the first mounting hole of the rocker arm to the rear end is formed, and the front surface of the second mounting hole of the pair of guides toward the front end thereof. A two-stage variable valve lift apparatus for an internal combustion engine, characterized in that a second groove into which the connecting member can be inserted is formed. The method of claim 1, wherein the hydraulic pressure providing means: An oil supply hole processed to communicate with the second mounting hole at a predetermined position of each guide; An oil distribution line connected to each oil supply hole; An oil supply line connected to the cylinder head gallery to supply oil to the oil distribution line; The two-stage variable valve lift device for an internal combustion engine, characterized in that consisting of an oil supply valve attached to the oil supply line.

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