JPH0151885B2 - - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION The present invention relates to a pump-type hydraulic valve system for an internal combustion engine that variably controls the opening and closing and timing of opening and closing of intake and exhaust valves of the internal combustion engine.

Most conventional intake/exhaust valve drive devices for internal combustion engines are mechanical valve actuation mechanisms using a valve arm, which connects a camshaft, tappet, push rod, etc. to a valve arm. There was no variable timing mechanism.

Further, since moving objects with large masses such as the push rod and the valve arm are continuously connected, the influence of inertial force is large, and the installation locations of cams and the like are restricted.

Therefore, in a hydraulic valve train for opening and closing the intake and exhaust valves of a diesel engine, Japanese Patent Application Laid-Open No. 1983-1999 relates to a valve timing changing device for a diesel engine that automatically changes the opening and closing timing of the intake and exhaust valves during engine operation. The invention of No. 44406 has been made.

In this case, two reeds are formed on the plunger, but since the barrel is integral and not divided, and each reed is not independent, it is not possible to compensate for the effects of other operations.

In addition, in a similar hydraulic valve train, the invention of JP-A-56-44405, which was made for the same purpose, requires a separate piston for controlling the valve opening, resulting in a complicated structure and poor durability. There is also the problem of inferiority.

Furthermore, for similar purposes, the invention of Japanese Patent Publication No. 46-22962 relates to a valve device for an internal combustion engine using a hydraulic valve train, and the invention of Japanese Patent Publication No. 47-22726 relates to a valve opening/closing timing adjustment device in a hydraulic valve train. However, in these cases, only the valve closing timing is adjusted, and the valve opening/closing timing is not adjusted.

SUMMARY OF THE INVENTION Therefore, the present invention aims to provide a pump-type hydraulic valve system that can control the valve opening and closing timing of intake and exhaust valves, and provides optimal opening and closing timing according to the load and rotational speed of the internal combustion engine. The ultimate goal was to set the timing and improve engine performance such as fuel efficiency and exhaust color.

That is, the pump-type hydraulic valve system of the present invention uses hydraulic oil generated by a plunger driven by a cam to open and close the intake and exhaust valves and the timing of the opening and closing using two reeds provided on the plunger and a plunger barrel. In a pump-type hydraulic valve system that is variable by changing the phase difference between two ports provided in the pump, the plunger barrel is formed of two pieces: an upper fixed plunger barrel and a lower rotary plunger barrel. Additionally, a rack for rotating the plunger and a rack for rotating the rotary plunger barrel are provided, respectively.

Embodiments of the present invention will be described below with reference to the drawings, and in each embodiment, the same parts are indicated by the same part numbers.

First, FIG. 1 is an overall vertical cross-sectional view of a pump-type hydraulic valve system for an internal combustion engine according to an embodiment of the present invention, and FIGS. 2 and 3 are simplified vertical cross-sectional views of the main parts of FIG. 1.

First, the hydraulic pressure generated by the plunger 2 driven by the cam 1 through the tappet 23 with the tappet roller 24 is transferred to the working piston 3 via the high pressure pipe 25.
0, the intake/exhaust valve 33 of the internal combustion engine is pushed down against the spring force of the valve spring 32, and as a result, the intake/exhaust valve 33 is opened/closed.

Next, this plunger 2 is provided with a lead 9 for valve closing control and a lead 10 for valve opening control, and these two leads 9 and 10 are connected to the upper fixed plunger barrel 26 which is divided into two parts. The intake/exhaust valve 33
The timing of opening and closing is made variable.

That is, the valve closing of the intake and exhaust valve 33 is controlled by the phase difference between the upper reed 9 and the hydraulic oil return port 13 of the fixed plunger barrel 26, and the lower reed 10 and the hydraulic oil return port 13 of the rotary plunger barrel 6 are controlled. The valve opening timing is controlled by the phase difference with the inlet port 7.

Furthermore, a rack 5 for rotating the rotary plunger barrel 6 is provided in addition to the rack 4 for rotating the plunger 2 via the pinion sleeve 3, and by rotating them independently, the rack 5 rotates the plunger 2.
The phase difference between the leads 9 and 10 and the hydraulic oil return port 13 and hydraulic oil inlet port 7 can be corrected independently.

At this time, depending on the rotation of the rotary plunger barrel 6, the upper lead 9 and the hydraulic oil return port 1
There is no change in the phase difference with 3, but when the plunger 2 rotates, the upper lead 9 and the lower lead 1
0 also rotates, which affects the phase difference between the lower lead 10 and the hydraulic oil inlet port 7. Therefore, it is necessary to rotate the hydraulic oil inlet 7 to correct the original phase difference.

In addition, in FIG. 2, the space 20 at the top of the plunger 2
A check valve 11 is provided at the upper part of the valve.

Therefore, as a control when the valve is opened, the intake and exhaust valve 33
By pulling the rack 5 as shown in FIG. 2, which shows changes in the opening timing of the rotary plunger barrel 6, the rotary plunger barrel 6 rotates clockwise, the hydraulic oil inlet port 7 also rotates, and the phase difference with the reed 10 changes. .

As the prestroke, which is initially zero, increases,
The hydraulic oil is not compressed until the plunger 2 rises by the prestroke amount, causing a delay in the movement of the working piston 30.

Next, as for the control when closing the valve, when the cam 1 is in the maximum lift state in FIG. 3, the oil pressure is maintained at the upper part of the operating piston 30, and the intake and exhaust valves 33 are also maintained in the open state shown by the solid line.

Therefore, when the cam 1 reaches the lift lowering section, the hydraulic pressure disappears, and as a result, the valve spring 32 causes the operating piston 30 to become the driving side, and the hydraulic oil is transferred to the plunger through the hydraulic oil return port 13. 2 into the space 20 at the top.

However, if there is a phase difference h between the lead 9 and the hydraulic oil return port 13 as shown in FIG. .

Therefore, as shown in FIG. 3, when the phase difference h is maximum, it is the oil confinement holding period, that is, the hydraulic lock period.

On the other hand, when changing the valve closing time of the intake/exhaust valve 33, the plunger 2 is rotated counterclockwise by pushing in the rack 4, the phase difference h between the lead 9 and the hydraulic oil return port 13 is reduced, and the hydraulic pressure is The lock period is reduced, resulting in an earlier closing period of the intake and exhaust valves 33.

Here, due to the rotation of the plunger 2, a change occurs in the phase difference between the reed 10 and the hydraulic oil inlet port 7, and if correction is necessary, the rack 5 is pushed and the rotary plunger barrel 6 is rotated to correct it.

Note that the valve opening timing of the intake/exhaust valve 33 during actual low load is delayed and the valve closing timing is advanced to shorten the overall valve opening period.

In the pump-type hydraulic valve system of the first embodiment, in order to shorten the valve opening period at low load, first rotate the plunger 2 counterclockwise using the rack 4 when viewed from above. Closing time is earlier,
The phase difference h in FIG. 3 becomes smaller.

At this time, since the plunger 2 is rotating counterclockwise, the relationship between the lead 10 and the hydraulic oil inlet port 7 is such that the pre-stroke increases, so there is a delay when the valve opens, but in reality The correction by Rack 5 becomes unnecessary.

Leads 9 and 1 of plunger 2 as shown above.
Since the position of 0 in the plunger 2 has a significant effect on the valve opening/closing timing, it is necessary to process it accurately. Therefore, in the present invention, the positions of the leads 9 and 10 could be determined accurately by the following procedure. That is, Fig. 4 a, b, c, d
To explain the method of machining the lead 9, an annular groove 34 is machined in the plunger 2 as shown in FIG. If we take the intersection of a line parallel to the axis of the plunger 2 on the outer periphery of the plunger 2 passing through the starting point of the lead 9 with the lower end of the groove 34, this point can be easily determined on the outer periphery of the plunger. The starting point of the lead 9 becomes clear, and the lead 9 can be accurately processed into the plunger 2. By providing a groove 35 similar to the groove 34 in the lead 10, the plunger 2 can be accurately processed in the same way as the lead 9.

Hereinafter, a detailed explanation of the operating principle of the pump-type hydraulic valve system of Example 1 will be given. First, in FIG. A diagram of the stroke of the working piston 30, ie, the lift H of the intake and exhaust valves 33, is shown in FIG.

Here, the working piston 30 pushed by the incompressible hydraulic oil starts lifting almost without delay, and the diameter D of the plunger 2 and the diameter d of the working piston 30 are D>
d, the lift of the working piston 30 increases by (D/d) ² compared to the plunger 2.

That is, H ₁ =H ₀ ×(D/d) ² .

Here, the lift H ₀ is the drive unit by cam 1,
In other words, it is the maximum lift in the lift diagram of the plunger 2, and the lift on the operating piston 30 side is the above-mentioned lift.
Limit lift to H less than H ₁ .

At this time, the operating piston 30 is limited to lift H, but the remaining oil corresponding to H _{1 -H} , which would normally lift to H 1, is discharged by the relief valve 31 provided in the operating piston 30. .

Next, during full lift, cam 1 after full lift.
Due to the characteristics of its profile, it has a shape consisting of points a, b, and c in FIG. 5, which maintains the total lift at the circular portion at the top.

When the entire lift section of the top circle ends, the section after point C begins, which has the same profile as the lift rising section but decreases in the opposite way.

Cam 1 is applied to the lift reduction section, and plunger 2
When the valve starts to descend, the hydraulic pressure pushing force from the plunger 2 disappears, and on the contrary, the operating piston 30 becomes the driving side due to the spring force of the valve spring 32 shown in FIG. shall be.

However, since there is a check valve 11 in the space 20 at the top of the plunger 2, the hydraulic oil flows through the nearby bypass passage 12, the hydraulic oil return port 13, and the communication holes 17 and 19. Although it attempts to return to the space 20 shown in FIG. 3, it cannot return until the lead 9 for valve closing control is connected to the hydraulic oil return port 13 that communicates with the plunger 2 of the bypass passage 12.

That is, until the hmm plunger 2 descends as shown in FIG. 3, the operating piston 30 stops moving and the intake and exhaust valves 33 remain open, which is the so-called oil confinement holding period or hydraulic lock period.

Therefore, the prestroke when the lead 10 for valve opening control and the hydraulic oil inlet port 7 coincide is 0 mm.
and when the phase difference h, which is the difference between the lead 9 for valve closing control and the hydraulic oil return port 13, is at its maximum value, the opening period of the intake and exhaust valves 33 is at its maximum. Here, the valve opening angle is θ°.

Next, when reducing the valve opening period or delaying the valve opening timing to reduce the valve opening timing, pull the rack 5 and rotate the rotary plunger barrel 6 clockwise while leaving the valve closing timing unchanged. , the hydraulic oil inlet port 7 also moves in the same direction, and the lead 10 for valve opening control and the hydraulic oil inlet port 7 change their positions relative to each other, producing a prestroke P _S as shown in FIG.

In this case, it is assumed that the plunger 2 does not rotate, and the hydraulic oil inlet port 7 moves in position as indicated by the arrow.

When the prestroke P _S occurs in this way, the operation of the working piston 30 shown in FIG. 2 becomes as shown in FIG. 7.

That is, while the cam 1, that is, the plunger 2 is rising by the amount of the prestroke _PS , the hydraulic oil is not compressed.

After the plunger 2 lifts by the pre-stroke P _S , the hydraulic oil inlet port 7 is closed by the lead 10 for controlling the opening of the valve, and the hydraulic oil is compressed and the working piston 30 operates.

In Figure 7, point a' is delayed by △θ compared to Figure 4,
As a result, the valve opening angle of the intake and exhaust valve 33 decreases to θ-Δθ.

Furthermore, in order to shorten the valve opening period by advancing the valve closing timing, press the rack 4 in FIG. 3 and rotate the pinion sleeve 3 counterclockwise when viewed from the top while keeping the valve opening timing unchanged. Interlockingly, the plunger 2 similarly rotates counterclockwise when viewed from the top, so the lead 9 for valve closing timing control
The hydraulic oil return port 13 also rotates, and its relative position with respect to the hydraulic oil return port 13 changes.

That is, the phase difference h at the uppermost position of the plunger 2
When the phase difference h decreases to h' as shown in _FIG . The valve opening angle of the exhaust valve 33 decreases to θ-Δθ ₁ .

However, since the plunger 2 has rotated counterclockwise when viewed from the top, the relative position between the valve opening timing control lead 10 and the hydraulic oil inlet port 7 has changed in the direction of increasing the prestroke.

When returning the valve opening timing to its original state, the rack 5 is pushed in so that the rotary plunger barrel 6 rotates counterclockwise when viewed from the top.

This correction amount can be achieved by pushing in rack 5 by the same amount as pushing in rack 4. Since the numbers of teeth and modules of rotary plunger barrel 6 and pinion sleeve 3 are the same, the stroke of rack 5 and pinion sleeve 3 are the same. The rotation angles match.

In the pump-type hydraulic valve device of the double-lead type valve opening/closing independent control type according to the first embodiment described above, the plunger barrel is divided into a fixed type and a rotary type, and the rotary type plunger barrel 6 is rotated.
Can compensate for the effects of other operations.

Generally, when the load is low, it is possible to delay the opening timing of the intake and exhaust valves 33 and advance the valve closing timing to reduce the overall valve opening timing, but in the timing change in the first embodiment, the plunger 2 is If the valve is rotated to advance the valve closing timing, the valve opening timing will be delayed due to this effect, so there is actually no need for correction.

Next, FIG. 9, FIG. 10, and FIG. 11 each show a pump type hydraulic valve system according to each embodiment of the present invention, which has almost the same configuration and function as Embodiment 1, and will not be described here. Only the differences will be explained.

First, in the second embodiment shown in FIG. 9, there are two plungers 2, one for the intake valve indicated by A and one for the exhaust valve indicated by B, per cylinder of an internal combustion engine, a fixed plunger barrel 26, and a rotary plunger. This is an integrated intake/exhaust type in which two barrels 6, etc. are housed in one body, and is more compact than the first embodiment, and further improves the supply of hydraulic oil from one location.

Next, in Embodiment 3 shown in FIG. 10, a rack hole is provided in each of the racks 4 and 5 of the apparatus of Embodiment 2 in the center of each plunger 2, and one rack 4 and 5 each has two rotations. The type plunger moves the barrel 6 and the plunger 2, and the hydraulic oil inlet port 7 is also in one place for both intake and exhaust, as well as for the exhaust valve. This is aimed at reducing the amount of noise and simplifying the device itself.

In addition, in the third embodiment shown in FIG. 11, the racks 4 and 5 in the second embodiment are divided in half at the center, and each rack 4 and 5 is
It is of the type with 4 racks that can also be used as rack holes for the intake and exhaust, each with separate holes.

Therefore, in an internal combustion engine to which the pump-type hydraulic valve system of the present invention is applied, it is possible to control the opening and closing periods of the intake and exhaust valves, and the timing of opening and closing can be changed, depending on the load and rotation speed of the engine. This has the effect of allowing the most appropriate timing to be set and improving engine performance such as fuel efficiency and exhaust color.

In addition, the opening and closing of the intake and exhaust valves can be controlled independently using two racks, and the valve opening and closing control section is centrally located in the plunger pump section, which saves space and allows for easy control. Another advantage is that the actuator is easy to control.

Furthermore, since the control mechanism is concentrated in the pump section as described above, the entire device can be made smaller and lighter.

[Brief explanation of drawings]

FIG. 1 is an overall vertical cross-sectional view of a pump-type hydraulic valve system for an internal combustion engine according to an embodiment of the present invention, FIGS. 2 and 3 are simplified vertical cross-sectional views of the main parts of FIG. 1, and FIG. , b, c, d are side views of the plunger, respectively;
An enlarged view of part A in figure a, an explanatory diagram of the starting point of the lead,
5 is a cross-sectional view of FIG. Figures 7 and 8 are side views of the main parts showing the relative position between the hydraulic oil inlet port and the valve opening control lead, and Figures 7 and 8 are diagrams similar to Figure 5 showing different states, respectively.
10 and 11 are overall vertical sectional views of the pump type hydraulic valve device in each embodiment of the present invention, respectively, FIG. 9 is the second embodiment, FIG. 10 is the third embodiment, and FIG. 11 shows the fourth embodiment. 1...Cam, 2...Plunger, 4, 5...Rack, 6...Rotary plunger barrel, 7...
Hydraulic oil inlet port, 9... Lead for control when valve is closed, 10... Lead for control when valve is open, 13... Hydraulic oil return port, 26... Fixed plunger barrel, 33... Intake/exhaust valve.

Claims (1)

[Claims] 1 The hydraulic oil generated by the plunger driven by the cam controls the opening and closing of the intake and exhaust valves and the timing of the opening and closing by adjusting the phase difference between the two leads provided on the plunger and the two ports provided on the plunger barrel. In a pump-type hydraulic valve system that is variable by changing the plunger, the plunger barrel is formed of two parts, an upper fixed plunger barrel and a lower rotary plunger barrel, and a rack for rotating the plunger and a rack for rotating the plunger and the rotary plunger barrel. A pump-type hydraulic valve system for an internal combustion engine, characterized in that each plunger barrel is provided with a rack for rotating it.