JP4016569B2 - Hydraulic valve gear - Google Patents

Description

[0001]
BACKGROUND OF THE INVENTION
The present invention relates to a hydraulic valve operating apparatus for driving intake and exhaust valves of an internal combustion engine.
[0002]
[Prior art]
2. Description of the Related Art Conventionally, a valve operating mechanism for driving intake and exhaust valves of an internal combustion engine has a camshaft driven by a crankshaft, and is pressed by a convex portion of a cam piece that is disposed on the camshaft and rotates, and is normally closed. In general, the valve is opened against a spring biased by.
[0003]
On the other hand, since the optimum intake / exhaust timing of the internal combustion engine depends on the operating state, particularly the engine speed, a variable valve mechanism that controls the valve opening timing has been conventionally considered. In the conventional variable valve mechanism, Many of them have a mechanism for mechanically changing the phase of the cam or mechanically switching so that another cam having a different phase or cam lift amount is effective. With such a configuration, it is possible to relatively easily perform variable control of some phase and lift amount.
[0004]
In addition, a valve operating device that drives an intake / exhaust valve by hydraulic pressure instead of a mechanical driving device has been proposed.
[0005]
For example, Japanese Utility Model Laid-Open No. 61-160204 discloses a valve that is opened and closed by a complete hydraulic operating force regardless of a camshaft or a valve spring, as shown in FIG. In this conventional example, hydraulic oil is supplied from a hydraulic tank to a high-pressure oil tank by a pump. The oil from this high-pressure oil tank is supplied and discharged while being controlled by four valves with respect to the hydraulic cylinder provided at the rear end of the valve so that free timing and lift amount can be performed. It has become.
[0006]
Furthermore, in the variable valve operating device disclosed in Japanese Patent Laid-Open No. 9-4424, the cam side plunger is driven by the cam, the hydraulic oil in the hydraulic chamber is pressurized and sent to the valve drive mechanism, and the timing is appropriately adjusted as necessary. By opening the pressurized hydraulic fluid to the low pressure side, the valve lift amount can be varied.
[0007]
However, in the prior art 61-160204 of the prior art, the spring in the valve closing direction is eliminated, and both the valve opening and closing are driven by hydraulic biasing force. Although it is improved, four valves must be controlled at an appropriate timing for one intake / exhaust valve, 16 valves in the case of four valves per cylinder, and in a multi-cylinder internal combustion engine If there is, it is necessary to control this by the number of cylinders, and there is a practically difficult aspect.
[0008]
Further, in Japanese Patent Laid-Open No. 9-4424 of the conventional example, although the lift amount of the valve mechanism can be controlled, the driving force is finally obtained by the pressing force of the plunger due to the rotation of the cam, so the timing can be freely changed. I can't.
[0009]
[Problems to be solved by the invention]
In the valve mechanism that is driven by the mechanical cam piece lift curve proposed in the past or the variable valve mechanism that changes or switches the phase of the cam, the cam piece eventually opens and closes completely. Since the timing and lift amount are governed, even if a variable mechanism is provided, the degree of freedom of the variable control width is low, and if the required specifications of the valve mechanism are different, it is necessary to redesign the camshaft and the peripheral mechanism. It was. Further, since the method for controlling the valve opening timing and the method for controlling the lift amount are different, there is a problem that the structure is complicated in order to change the valve opening timing and the lift amount.
[0010]
On the other hand, as for the valve operating device by hydraulic pressure, for example, the valve operating device shown in the above-mentioned literature is known, but as described above, the problem to be solved still remains.
[0011]
The present invention can reduce the power loss of the engine by reducing the amount of pressure oil for driving the intake / exhaust valve of the internal combustion engine as much as possible, reducing the energy required for driving in the hydraulic valve operating device. A valve operating device is provided. Moreover, in such a valve operating apparatus, the valve operating mechanism which can change a lift timing and a lift amount freely is provided.
[0012]
[Means for Solving the Problems]
In order to achieve the above object, a hydraulic valve operating apparatus according to the present invention is a hydraulic valve operating apparatus for driving an intake valve or an exhaust valve of an internal combustion engine. The pressure chamber (4) is formed when the valve (2) is closed and the rear end surface of the valve (2) is a pressure receiving surface (9), and when the valve (2) moves a predetermined amount when the valve is opened, the pressure chamber ( and 4) a low pressure of the hydraulic cylinder being connected (3), a pressure oil supply device for supplying pressure oil to the pressure chamber when the valve is opened (4), a spring for urging the valve (2) in the closing direction (14), and when the valve (2) is opened, pressure oil is supplied from the pressure oil supply device to the pressure chamber (4) to give kinetic energy in the valve opening direction to the valve (2). And the pressure chamber (4) is connected to the hydraulic cylinder (3) until the pressure is increased. Stopping the supply of pressurized oil to the chamber (4), by then inertial force, the provided valve (2) is configured to continue the movement of the valve opening direction, further, the hydraulic cylinder (3) is communicated The passage (33) is connected to another hydraulic cylinder (3 ′), and the communication passage (33) is provided with an adjustment valve (34), and the valve (2) is adjusted by adjusting its opening degree. The lift amount and speed of the vehicle are changed.
[0014]
The pressure supply port (21) for supplying pressure oil to the pressure chamber (4) is provided with an operating piston (5) for blocking the pressure supply port (21), and the operating piston (5) A pressure control chamber (7) provided with a control valve (17) is formed on the side opposite to the pressure supply port (21). Further, the pressure oil supply device stores an accumulator for accumulating constant pressure oil. A pressure vessel (23) is provided, and pressure oil from the pressure accumulator (23) is supplied to the pressure control chamber (7) and the pressure supply port (21) side of the working piston (5), When opening the valve, the control valve (17) is opened to lower the hydraulic pressure in the pressure control chamber (20), the operating piston (5) is moved, and pressure oil is supplied to the pressure chamber (4). It is a feature.
[0015]
According to the above configuration, in the hydraulic valve operating apparatus according to the present invention, by providing the hydraulic pressure for driving the intake / exhaust valve only at the initial stage when the valve is opened, the energy required for driving can be reduced, and at the same time The timing can be set freely without any mechanical restrictions such as camshafts.
[0016]
Furthermore, after the valve 2 is opened, the lift amount and the lift speed of the valve 2 can be freely changed by controlling the opening degree of the adjusting valve 34 provided in the communication path 33.
[0017]
According to this configuration, various variable controls are possible by changing the initial pressure applied to the valve, the supply time of the pressure, the opening of the regulating valve, the pressure in the pressure accumulating chamber, etc., and the hydraulic valve with a very high degree of freedom An apparatus can be realized.
[0018]
DETAILED DESCRIPTION OF THE INVENTION
Hereinafter, embodiments of the present invention will be described with reference to the drawings.
A schematic external view of the valve gear of the present invention is shown in FIG. 1, and a specific configuration is shown in FIG.
[0019]
The hydraulic valve operating apparatus 1 of the present invention drives an intake / exhaust valve 2 slidably held up and down. The valve 2 is urged in the valve closing direction by a spring flange 13 provided around the shaft of the valve 2 and a spring 14 provided in a spring chamber 32 in the valve case 31.
[0020]
The rear end portion of the valve 2 has a pressure chamber 4, and the rear end surface of the valve 2 is a pressure receiving surface 9 to which a driving force is applied.
[0021]
The pressure chamber 4 is provided with a pressure supply port 21 for supplying hydraulic oil to the pressure chamber and an operation piston 5 controlled by the pressure control unit 6, thereby opening and closing the pressure supply port.
[0022]
There is a pressure reservoir 8 for energizing the working piston upward (in the valve opening direction) by supplying high pressure hydraulic oil to the tip of the working piston 5, and high pressure hydraulic oil is supplied to the other end. The pressure control chamber 7 urges the operating piston 5 downward (in the valve closing direction) together with a built-in spring.
[0023]
The hydraulic fluid is always supplied to the pressure reservoir 8 and the pressure control chamber 7 through a high pressure oil supply passage (19, 20, 28, 29) from a pressure accumulator 23 that accumulates high pressure hydraulic oil supplied from a hydraulic supply pump. Has been.
[0024]
When the valve is closed, high pressure hydraulic fluid is supplied to the rear end (pressure control chamber 7) and the front end (pressure reservoir 8), and the urging force in the valve opening direction and the valve closing direction is substantially balanced. The valve closed state can be maintained by a spring disposed in the pressure control chamber 7.
[0025]
When the valve 2 is lowered when the valve is opened, the operating piston 5 is raised by the operation of the pressure control unit 6 that opens and closes the passage 16 of the orifice that faces the pressure control chamber 7 and is opened to the reservoir tank. Is supplied while injecting hydraulic oil. The operation will be described below with reference to FIG.
[0026]
The pressure control unit 6 includes an electromagnetic coil 35, an armature 17, and a spring 36 leak passage 18. In a steady state (a state where the valve 2 is closed), the armature 17 closes the orifice 16, and the working piston 5 is pressurized. The pressure supply port is closed so that the high-pressure hydraulic oil is not injected from the supply port (FIG. 3- (a)).
[0027]
When the valve 2 is opened, first, the electromagnetic coil 35 is energized in the pressure control unit 6 to raise the armature 17 and the orifice 16 is opened. When opened, the high pressure hydraulic oil in the pressure control chamber 7 leaks through the orifice 16, so the pressure in the pressure control chamber 7 decreases.
[0028]
When the pressure in the pressure control chamber 7 decreases, the pressure balance with the pressure reservoir located at the tip of the working piston 5 is lost, and the urging force of the pressure reservoir rising (in the valve opening direction) by the high pressure hydraulic oil is The operating piston 5 rises by overcoming the urging force in the valve closing direction by the pressure and the spring.
[0029]
When the working piston 5 rises, the pressure supply port 21 is opened, and the high-pressure hydraulic oil supplied from the pressure accumulator 23 is supplied while being injected toward the pressure chamber. The pressure of the accumulator 23 can be set arbitrarily, but for example, a pressure of about 80 MP is set. This injected oil collides with the pressure-receiving surface at the rear end of the valve, giving downward kinetic energy to the valve 2 and moving the valve 2 in the valve opening direction (FIG. 3B).
[0030]
When the valve 2 moves in the valve opening direction by a predetermined amount, the pressure chamber 4 communicates with the cylinder 3 positioned below it, and the pressure is reduced at once when the high-pressure hydraulic oil injected into the pressure chamber 4 flows into the low-pressure cylinder. . Even if the pressure decreases, the valve continues to move in the opening direction by a predetermined amount of kinetic energy of the valve (FIG. 3C).
[0031]
Then hydraulic valve system overall specific operating FIGS. 2 and 3, and illustrated by the timing chart shown in FIG.
[0032]
In the present invention, as shown in the embodiment of FIG. 2, the valve 2 has a cylinder 3 communicated with the pressure chamber 4 after starting the lift and another cylinder 3 ′ communicated with the cylinder 3. . The cylinders 3 and 3 ′ are connected through a communication path 33. An adjustment valve 34 whose opening area can be variably controlled is provided in the middle of the communication path. A relief valve 27 for opening the hydraulic oil at low pressure and opening the hydraulic oil is provided in the cylinder 3 ′ located on the downstream side of the cylinder 3. Further, a replenishment path 38 for replenishing hydraulic oil in response to a pressure drop in the cylinder 3 ′ is also provided.
[0033]
The valve opening operation of the valve 2 in this embodiment will be described. The target valve opening timing t1 of the valve is determined according to the operating state of the engine (details are omitted). Energization to the pressure control unit 6 is started at this timing. The operation in which the hydraulic pressure is supplied from the pressure supply port 2 to the pressure chamber 4 by the pressure control unit 6 is as described with reference to FIG. This energization start timing is set retroactively for a predetermined period because there is a time lag between the start of energization and the actual supply of hydraulic pressure and the start of lift of the valve.
[0034]
The lift of the valve 2 is started from time t1. In the initial stage of the lift start, as shown in FIG. 3B, the pressure chamber 4 is a space substantially closed by the pressure receiving surface of the valve 2, and moves to the valve by vigorously injected hydraulic pressure. Given the energy, the lift increases rapidly. When the lift amount exceeds a predetermined amount (line (a) in FIG. 4), the pressure chamber 4 communicates with the cylinder 3 and the pressure applied to the pressure receiving surface 9 is suddenly reduced. At this time, the injection of hydraulic oil from the pressure control unit 6 is basically stopped, and the valve lift is continued by the given kinetic energy.
[0035]
After the pressure chamber 4 communicates with the cylinder 3, the volume of the cylinder 3 increases as the valve moves. Therefore, hydraulic oil flows into the cylinder 3 from the replenishment path 38 through the cylinder 3 ′ and the communication path 33.
[0036]
Here, energization for opening the regulating valve 34 that has been closed is started (t1 to t1). Actually, even if energization of the regulating valve is started at t1, the valve is opened with a time delay, so that the regulating valve is actually opened when the valve lift exceeds the line (a). Is preferred. If the opening degree of the regulating valve 34 is large, compensation from the cylinder 3 'is performed quickly, and the high lift speed is maintained without impairing the valve opening speed.
[0037]
The graph shown by the one-dot chain line in FIG. 4 is the case where the regulating valve is fully opened, that is, when the opening degree is 100%. At this time, the hydraulic pressure in the cylinder 3 is quickly compensated, and the deceleration of the valve lift is minimized ( Maximum lift speed). Also, the solid line shows the case where the opening degree of the regulating valve 34 is 50%, and the valve lift is as shown by the solid line. A two-dot chain line shows a case where the opening degree is 20%. Since the compensation of the hydraulic pressure to the cylinder 3 ′ to the cylinder 3 is largely limited by the opening degree of the regulating valve 34, the valve lift speed is kept low. . The valve thus controlled is lifted until the maximum lift amount is reached.
[0038]
When the maximum lift required by the valve is reached, the regulating valve 34 is completely closed. Since the lift of the valve is performed while expanding the volume of the cylinder 3, the volume cannot be increased if the hydraulic oil filling from the cylinder 3 'through the communication path 33 is stopped. That is, when the adjustment valve 34 is closed in the maximum lift state, the valve stops moving and the lift state is maintained. Further, in order for the valve to return to the valve closing side, it is necessary to return the hydraulic oil supplemented to the cylinder 3 to the cylinder 3 ′ side through the communication path 33 this time. Next, valve closing control of the valve 2 will be described.
[0039]
The valve closing control is performed based on a target valve closing timing (t3: details are omitted) determined according to the operating state of the engine. From the state where the valve is fully lifted, that is, the state where the adjustment valve 34 is fully closed, the adjustment valve 34 is opened based on the target valve closing timing. By opening the regulating valve 34, the hydraulic oil can be returned from the cylinder 3 to the cylinder 3 'that has been cut off until then, and the valve 2 is moved while the volume of the cylinder 3 is reduced by the spring force of the spring 14. The valve is closed.
[0040]
Similarly to the time of opening the valve, the valve closing speed can be variably controlled by adjusting the opening of the adjusting valve 34 during the valve closing operation. When the opening degree is 100% indicated by the solid line at t3 in FIG. 4, the maximum valve closing speed is obtained. When the opening degree is reduced as indicated by the dotted line (50%), the valve closing operation is slow. Further, when the pressure chamber 4 starts to be closed by the pressure receiving surface 9 at the rear end of the valve during the valve closing operation, the valve only leaks from a slight gap around the rear end of the valve, so that the valve moving speed is damped just before the lift ends. The This damping effect also has the effect of preventing undesired bounce of the valve (the closed valve opens again due to the momentum reaction when the valve is closed).
[0041]
Further, by closing the adjustment valve 34 at the maximum lift time, the valve lift is stopped and the lift state is maintained. This is the lift amount as shown by the dotted line (b) in FIG. 4, that is, from t1. When the regulating valve 34 is closed at the time t2 ′ when a predetermined time has elapsed, the lift amount can be controlled to be small (in this case, half lift). When the valve is closed (for example, t4 ′), the adjustment valve 34 may be opened in the same manner as described above.
[0042]
As for the pressure accumulator of the above embodiment, when the engine has a plurality of cylinders, it may be a common rail that is a common pressure accumulator for each cylinder, and in order to maintain the pressure constant, feedback control by a pressure sensor provided in the accumulator However, a pressure holding structure with a relief valve that relieves at a constant pressure may be used.
[0043]
Needless to say, the pressure hydraulic oil may be a dedicated hydraulic oil, or the same control can be performed even when engine lubricating oil or fuel oil is used. The hydraulic oil is supplied to the pressure accumulator by a pump, but when a common rail is used in the fuel supply system for the combustion chamber of the engine, the pressure can be supplied from the common rail.
[0044]
【The invention's effect】
As described above, according to the hydraulic valve operating apparatus of the present invention, it is possible to effectively utilize the kinetic energy of the valve provided by the hydraulic oil that drives the intake and exhaust valves, and to minimize the amount of hydraulic oil for driving. . Therefore, the power required to increase the pressure of the hydraulic oil is reduced and the power loss of the internal combustion engine is reduced. Furthermore, the lift amount and the lift speed of the valve can be freely changed by controlling the opening degree of the adjusting valve provided in the hydraulic valve operating device.
[Brief description of the drawings]
FIG. 1 is an external view of a valve operating apparatus according to the present invention.
FIG. 2 is an internal cross-sectional view showing an embodiment of the present invention.
FIG. 3 is a drawing showing the operation of the ac pressure control unit and the opening / closing control of the valve.
FIG. 4 is a timing chart of the regulating valve 34, the solenoid valve H and the valve lift according to the present invention.
FIG. 5 is a diagram showing a prior art.
[Explanation of symbols]
DESCRIPTION OF SYMBOLS 1 Hydraulic type valve apparatus 2 Intake / exhaust valve 3 Cylinder 4 Pressure chamber 5 Actuation piston 6 Pressure control unit 7 Pressure control chamber 8 Pressure reservoir 9 Pressure receiving surface 10, 11, 18 Leak passage 12 Reservoir tank 13 Spring flange 14 Valve spring 15 Intake / exhaust port 16 Orifice 17 Control valve armature 19, 20, 28, 29 High pressure oil supply path 21 Pressure supply port 22 ECU
23 pressure accumulator common rail 24 pressure sensor 25 hydraulic supply pump 26 check valve 27 relief valve 30 cylinder head 31 valve case 32 spring chamber 33 communication path 34 adjustment valve 35 electromagnetic coil 36 spring 37 pump control valve 38 replenishment path

Claims (2)

A hydraulic valve operating device for driving an intake valve or an exhaust valve of an internal combustion engine,
A pressure chamber (4) formed when the valve (2) of the intake valve or the exhaust valve is closed and having the rear end surface of the valve (2) as a pressure receiving surface (9), and the valve (2) when opened the pressure chamber when a predetermined amount of movement and low pressure of the hydraulic cylinder (3) connected (4), a pressure oil supply device for supplying pressure oil to the pressure chamber (4) when the valve is opened, the valve (2 And a spring (14) for urging the valve in the valve closing direction,
When the valve (2) is opened, pressure oil is supplied from the pressure oil supply device to the pressure chamber (4) to give kinetic energy in the valve opening direction to the valve (2). The supply of pressure oil to the pressure chamber (4) is stopped until 4) is connected to the hydraulic cylinder (3), and then the valve (2) moves in the valve opening direction due to inertial force. Configured to continue, and
The hydraulic cylinder (3) is connected to another hydraulic cylinder (3 ′) by a communication path (33), and an adjustment valve (34) is provided in the communication path (33) to adjust its opening degree. Accordingly, the lift and speed of the valve (2) are changed. The pressure supply port (21) that supplies pressure oil to the pressure chamber (4) is provided with an operating piston (5) that blocks the pressure supply port (21), and the pressure supply of the operating piston (5). A pressure control chamber (7) provided with a control valve (17) is formed on the side opposite to the port (21). Further, the pressure oil supply device has a pressure accumulator (accumulating pressure oil). 23) and pressure oil from the pressure accumulator (23) is supplied to the pressure supply port (21) side of the pressure control chamber (7) and the working piston (5), and the valve is opened. Sometimes, the control valve (17) is opened to lower the hydraulic pressure of the pressure control chamber (20), the operating piston (5) is moved, and pressure oil is supplied to the pressure chamber (4). The hydraulic valve operating apparatus according to claim 1.

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