JP2697709B2 - Valve control system for engine valve train - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a valve train for an engine, and more particularly to a valve control system for the engine.

[0002]

2. Description of the Related Art In a conventional engine valve operating system, a rocker arm is driven by a cam and swings to open and close an intake valve or an exhaust valve.

[0003]

However, in the conventional engine valve train, the valve opening / closing timing is fixedly set. For example, when a high-speed cam that emphasizes the engine high-speed operation performance is used, the engine low-speed operation performance is reduced. If a low-speed cam that emphasizes low-speed driving performance is used, there is a problem that high-speed driving performance is impaired. In addition, a mechanism has been proposed in which a high-speed cam and a low-speed cam are provided, and a rocker arm is moved in the axial or vertical direction to switch a driven cam, but the rocker arm can swing and can be moved in the axial or vertical direction. The rocker arm must be fixed as much as possible, a driving force is required to move the heavy rocker arm, and in the case of axial movement, the contact portion of the rocker arm with the valve moves, so the valve contact of the rocker arm There is a problem that the part must be enlarged and the contact position cannot be centered.

The present invention is intended to solve such a problem, and can exhibit excellent driving performance over a wide range from low-speed engine operation to high-speed engine operation with a simple configuration without moving the rocker arm. I did it,
An object is to provide a valve control device for an engine valve train.

[0005]

SUMMARY OF THE INVENTION Therefore, the present invention provides a high-speed cam having a cam profile for high-speed engine operation, a low-speed cam having a cam profile for low-speed engine operation, and a valve in the engine valve train. It has a valve side rocker arm that abuts, a cam side rocker arm that swings by being driven by a cam, and a rocker arm engagement / disengagement mechanism that connects and releases the rocker arms with plungers that move in cylinder holes provided in the rocker arms. By connecting / disconnecting the rocker arms, the valve-side rocker arm is switched between a state driven by the high-speed cam and a state in which the valve-side rocker arm is driven by the low-speed cam.

In the above-described valve control apparatus for an engine valve system according to the present invention, the valve is suitable for high-speed operation or low-speed operation with a simple configuration (by operating one of the high-speed cam side rocker arm and the low-speed cam side rocker arm). It is opened and closed at the valve timing.

[0007]

BRIEF DESCRIPTION OF THE DRAWINGS FIG. 1 is a plan view of a valve control device for an engine valve system according to an embodiment of the present invention; FIG.
2 is a side view schematically showing a state viewed from the direction of arrows II-II in FIG. 1, FIG. 3 is a side view for explaining the operation corresponding to FIG. 2, and FIG. 5 and 6 are schematic diagrams for explaining the operation of the oil control valve, FIG. 7 is a block diagram showing a control system of the oil control valve, and FIGS. Are schematic diagrams for explaining the operation, FIG. 11 is an operation mode diagram of the engine, and FIG. 12 is a flowchart for explaining the operation.

As shown in FIG. 1, a high-speed cam 1 having a cam profile for high-speed operation of the engine and a low-speed cam 2 having a cam profile for low-speed operation of the engine are provided on a cam shaft 3 in the engine valve system. ing. A high-speed cam-side rocker arm 4 driven by the high-speed cam 1 and oscillating, and a low-speed cam-side rocker arm 5 driven by the low-speed cam 2 and oscillated are pivotally mounted on the rocker shaft 6, respectively.

Further, a valve-side rocker arm 7 having a shape as shown in FIG. 4 is pivotably attached to a rocker shaft 6 so as to be sandwiched between the high-speed cam-side rocker arm 4 and the low-speed cam-side rocker arm 5. And the valve side rocker arm 7
The valve 8 can be engaged with the upper end of the stem 8a of the valve 8, and the valve 8 is opened and closed by the swing of the valve side rocker arm 7. As shown in FIG. 2, a spring receiver 36 is attached to the upper end of the valve stem 8a, and the valve 8 is urged in the closing direction by a valve spring 37 via the spring receiver 36.

A first rocker arm engaging / disengaging mechanism M1 for connecting and releasing the high-speed cam side rocker arm 4 and the valve side rocker arm 7 is provided. That is, the hydraulic actuator 9 is built in the high-speed cam-side rocker arm 4. The actuator 9 includes a cylinder portion 11 formed on the high-speed cam-side rocker arm 4 and a piston 13 inserted into the cylinder portion 11. The return spring 15 urges the piston 13 in the direction of arrow a in FIG. The plunger 23 is connected to the piston 13 via a rod 21.

The valve side rocker arm 7 has a hole 25 into which the plunger 23 can be inserted when the high speed cam side rocker arm 4 is in contact with the base circle portion of the high speed cam 1. Further, an oil chamber 17 is formed in a space surrounded by the cylinder portion 11 and the piston 13 of the high-speed cam side rocker arm 4, and the oil chamber 17 communicates with an oil passage 19 in the rocker shaft 6.

The oil passage 19 is connected to an oil passage 29 outside the rocker shaft 6.
And connected to a high-speed oil control valve (hereinafter referred to as “high-speed OCV”) 26 through the
When no control signal (current) is supplied from the controller 38 (see FIG. 7) to the excitation coil 27 of the V26, the plunger 28 is in the position shown in FIG. A state in which pressure oil is supplied from the oil passage 30 to the oil chamber 17 via the oil passages 29 and 19, and conversely, a control signal (current) is supplied from the controller 38 (see FIG. 7) to the exciting coil 27 of the high-speed OCV 26. Then, the plunger 28 is in the position as shown in FIG. 6 (in a valve-on state), and from the oil chamber 17 to the atmospheric pressure oil passage 31 (reservoir oil passage) via the oil passages 19 and 29. Oil is being drained.

Therefore, when the pressurized oil is supplied to the oil chamber 17 in the high-speed cam side rocker arm 4 through the oil passage 19, the plunger 23 is pushed out in the direction of the arrow b, and the plunger 23 is opened as shown in FIGS. The high-speed cam-side rocker arm 4 and the valve-side rocker arm 7 are connected to engage with the hole 25 of the side rocker arm 7. When the oil is discharged from the oil chamber 17, the plunger 23 is retracted in the direction of arrow a by the return spring 15, and the engagement of the plunger 23 with the hole 25 of the valve side rocker arm 7 is released as shown in FIG. Therefore, the high-speed cam side rocker
The system 4 and the valve-side rocker arm 7 are released.

A second rocker arm engaging / disengaging mechanism M2 for connecting and releasing the low speed cam side rocker arm 5 and the valve side rocker arm 7 is provided. That is, the hydraulic actuator 10 is built in the low-speed cam-side rocker arm 5. The actuator 10 includes a cylinder portion 12 formed on the low-speed cam-side rocker arm 5 and a piston 14 inserted into the cylinder portion 12. And a return spring 16 for urging the piston 14 in the direction of arrow a 'in FIG.

A plunger 24 is connected to the piston 14 via a rod 22. When the low-speed cam-side rocker arm 5 is in contact with the base circle portion of the low-speed cam 2, the plunger 24 can also be inserted into the hole 25 of the valve-side rocker arm 7. Further, the cylinder portion 12 of the low-speed cam side rocker arm 5 and the piston 1
An oil chamber 18 is formed in a space surrounded by 4 and communicates with an oil passage 20 in the rocker shaft 6.

The oil passage 20 is connected to the oil passage 2 outside the rocker shaft 6.
9 'is connected to a low-speed oil control valve (hereinafter referred to as "low-speed OCV") 26', and is connected to an exciting coil 27 'of the low-speed OCV 26' by a controller 3 '.
In the state where the control signal (current) is not supplied from FIG. 8 (see FIG. 7), the plunger 28 'is in the position as shown in FIG.
Pressure oil is supplied to the oil chamber 18 via the oil passages 29 'and 20 from the side, and conversely, from the controller 38 (see FIG. 7),
When a control signal (current) is supplied to the exciting coil 27 'of the CV 26', the plunger 28 'is in the position shown in FIG.
The oil is discharged from 8 to the atmospheric pressure oil passage 31 '(reservoir-side oil passage) through oil passages 20, 29'.

Accordingly, when pressure oil is supplied to the oil chamber 18 in the low speed cam side rocker arm 5 through the oil passage 20, the plunger 24 is pushed out in the direction of arrow b ', and as shown in FIG. 7 holes 25
Therefore, the low-speed cam side rocker arm 5 and the valve side rocker arm 7 are connected. Oil chamber 18
When the oil is drained from the plunger 24, the plunger 24 is retracted in the direction of arrow a 'by the return spring 16, and the plunger 24 is moved to the valve side rocker arm 7 as shown in FIGS.
Of the low-speed cam side rocker arm 5 and the valve side rocker arm 7 are released.

The OCVs 26, 26 'are turned on by a control signal from the controller 38, and the oil chambers 17, 1 are turned on.
When the oil is discharged from the plunger 8, the plungers 23 and 24 are retracted in the directions of the arrows a and a 'by the return springs 15 and 16, respectively, as shown in FIG.
Since both the lock members 3 and 24 are released from engagement with the holes 25 of the valve side rocker arm 7, the high speed cam side rocker arm 4 and the valve side rocker arm 7 are released, and the low speed cam side rocker arm 5 and the valve side rocker arm 7 are released. Is released.

Further, a timing cam 32 is provided at a pivotally connected portion of the high-speed cam side rocker arm 4 and the low-speed cam side rocker arm 5 on the rocker shaft 6, and each of the timing cams 32 is connected to each of the rocker arms 4,5. Is in contact with the base circle portions of the cams 1 and 2, the timing cam followers 33 having a substantially cylindrical shape are largely swung outward in the radial direction of the rocker shaft 6, and the timing levers 34 and 35 are rotated. Can be disengaged by riding on the pistons 13 and 14 (see FIG. 3). When the rocker arms 4 and 5 start swinging, the timing cam followers 33 do not swing outward in the radial direction of the rocker shaft 6, so that the timing lever 3
The state where the 4.35 is engaged with the end faces of the pistons 13 and 14 is maintained (see FIG. 2).

By the way, the control signals from the controller 38 are supplied to the OCVs 26 and 26 'as described above.
As shown in FIG. 7, signals from a throttle sensor 39 for detecting the opening of the throttle valve, a speed sensor 40 for detecting the engine speed, a water temperature sensor 41 for detecting the engine cooling water temperature, an idle sensor 42 for detecting the engine idle state, and the like. When the controller 38 determines that the zone is in the "high-speed range" shown in FIG. 11 based on the signal from each sensor, the controller 38 turns off the high-speed OCV 26 and turns on the low-speed OCV 26 '. If it is determined that the zone is in the “low speed range”, the high speed side OCV 26 is turned on, while the low speed side OCV 26 ′ is turned off, and the “stop cylinder range” is set.
Is determined to be the zone of both OCV2 on the high and low speed side.
Turn on both 6, 26 '. Here, controller 3
FIG. 12 shows a control flow for turning on and off the OCVs 26 and 26 'according to FIG.

With the above configuration, when the engine is in the "high speed zone" shown in FIG. 11, step A in FIG.
At steps 1 and 2, the NO route is taken, and the high-speed OCV 26 is turned off and the low-speed OCV 26 ′ is turned on by a signal from the controller 38 (see step A 3 in FIG. 12). As a result, the pressure oil is supplied to the oil chamber 17 and the oil is discharged from the oil chamber 18, so that the plunger 23 with the high-speed cam side rocker arm 4 as shown in FIG.
Engages with the hole 25 of the valve side rocker arm 7 and the plunger 24 with the low speed cam side rocker arm 5 comes off the hole 25 of the valve side rocker arm 7.

Therefore, the valve-side rocker arm 7 swings integrally with the high-speed cam-side rocker arm 4, and as a result,
The valve 8 is driven to open and close at a valve timing suitable for high-speed operation. On the other hand, when the engine is in the "low speed range" zone shown in FIG.
In step A2, a YES route is taken, and controller 3
8, the high-speed OCV 26 is turned on and the low-speed OCV 26 'is turned off (see step A4 in FIG. 12). As a result, the pressure oil is supplied to the oil chamber 18 and the oil is discharged from the oil chamber 17, so that the plunger 24 with the low-speed cam side rocker arm 5 as shown in FIG.
Engages with the hole 25 of the valve-side rocker arm 7 and the plunger 23 with the high-speed cam-side rocker arm 4 comes off the hole 25 of the valve-side rocker arm 7.

Therefore, the valve-side rocker arm 7 swings integrally with the low-speed cam-side rocker arm 5, and as a result,
The valve 8 is driven to open and close at a valve timing suitable for low-speed operation. Further, when the engine is in the zone of the "rest cylinder region" shown in FIG. 11, a YES route is taken in step A1 of FIG.
V26 and 26 'are turned on (see step A5 in FIG. 12). As a result, the oil is discharged from both oil chambers 17 and 18, and as shown in FIG.
From the hole 25 of the valve-side rocker arm 7.

Therefore, the valve-side rocker arm 7 does not swing even if the high-speed cam-side rocker arm 4 and the low-speed cam-side rocker arm 5 swing, so that the valve 8 is not opened or closed. That is, the cylinder 8 is in a stopped state in which the valve 8 is stopped. The timing of engagement and disengagement of the plungers 23 and 24 with the hole 25 is appropriately set by timing levers 34 and 35. Further, this engine is configured as, for example, an in-line four-cylinder engine.
The opposing cam is selected as the same type of cam (for example, if the one shown in FIG. 1 is used for the second cylinder, the cam closer to the second cylinder of the first cylinder is made a high-speed cam, and the cam closer to the second cylinder of the third cylinder is used. Is a low-speed cam.), And the hydraulic circuit system for controlling each hydraulic actuator can be simplified.

[0025]

As described above in detail, according to the valve control apparatus for an engine valve operating system of the present invention, a high-speed cam having a cam profile for high-speed engine operation, A low-speed cam having a cam profile, a valve-side rocker arm in contact with a valve, a cam-side rocker arm that is driven by the cam to swing, and a rocker arm connected by a plunger that moves in a cylinder hole provided in each of the rocker arms. Having a rocker arm engaging / disengaging mechanism to be released, connecting between rocker arms
A simple configuration in which the valve-side rocker arm is driven by the high-speed cam and the valve-side rocker arm is driven by the low-speed cam upon release is a simple configuration. There is an advantage that excellent driving performance can be exhibited over the range.

[Brief description of the drawings]

FIG. 1 is a partially cutaway plan view showing a valve control device for an engine valve train as one embodiment of the present invention.

FIG. 2 is a side view schematically showing a state viewed from the direction of arrows II-II in FIG.

FIG. 3 is a side view for explaining the operation corresponding to FIG. 2;

FIG. 4 is a side view showing the valve-side rocker arm.

FIG. 5 is a schematic diagram for explaining the operation of the oil control valve.

FIG. 6 is a schematic diagram for explaining the operation of the oil control valve.

FIG. 7 is a block diagram showing a control system of the oil control valve.

FIG. 8 is a schematic diagram for explaining the same operation.

FIG. 9 is a schematic diagram for explaining the same operation.

FIG. 10 is a schematic diagram for explaining the same operation.

FIG. 11 is an operation mode diagram of the engine.

FIG. 12 is a flowchart for explaining the same operation.

[Explanation of symbols]

 DESCRIPTION OF SYMBOLS 1 High speed cam 2 Low speed cam 3 Cam shaft 4 High speed cam side rocker arm 5 Low speed cam side rocker arm 6 Rocker shaft 7 Valve side rocker arm 8 Valve 8a Valve stem part 9,10 Actuator 11,12 Cylinder part 13,14 Piston 15,16 Return spring 17, 18 Oil chamber 19, 20 Oil passage 21, 22 Rod 23, 24 Plunger 25 hole 26, 26 'Oil control valve 27, 27' Excitation coil 28, 28 'Plunger 29-31, 29'-31' Oil passage 32 Timing cam 33 Timing cam follower 34, 35 Timing lever 36 Spring receiver 37 Valve spring 38 Controller 39 Throttle sensor 40 Speed sensor 41 Water temperature 42 Idle sensor M1 First rocker arm disengaging mechanism M2 Second rocker arm disengaging mechanism

Claims (1)

(57) [Claims] 1. A high-speed cam having a cam profile for high-speed operation of an engine, a low-speed cam having a cam profile for low-speed operation of an engine, a valve-side rocker arm in contact with a valve, and a cam in the engine valve train. A rocker arm that swings and swings, and a rocker arm engaging / disengaging mechanism that connects and releases between rocker arms by a plunger that moves in a cylinder hole provided in each of the rocker arms. A valve control device for an engine valve operating system, wherein a state in which a rocker arm is driven by the high-speed cam and a state in which the valve-side rocker arm is driven by a low-speed cam are switched.