JPH0621533B2 - Intake valve closing timing retarder for intake valve operating system of internal combustion engine - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION <Industrial Field of Application> The present invention controls intake valve closing timing in a multi-cylinder engine in accordance with engine rotation speed to improve intake charging efficiency. Regarding the valve closing timing adjusting device, as shown in FIGS. 2 and 13 for the prerequisite structure, each cylinder 7 of the intake valve operating device 15 of the multi-cylinder internal combustion engine 1 is described.
The retard angle actuating body 20 is interposed between the intake cam 18 and the follower 21, and each retard angle actuating body 20 is moved in the circumferential direction of the intake cam 18 in synchronization with the intake cam 18 by each retard angle driving device 44. The present invention relates to a structure in which the valve closing timing of the intake valve 10 is retarded by reciprocal driving, and the retarding reciprocating drive distance of the retarding actuator 20 is adjustable by the retarding adjustment device 34.

<Conventional Example> Conventionally, as this type of apparatus, the one disclosed in Japanese Patent Laid-Open No. 59-93909 is known.

It is constructed as shown in FIG.

The retarder 20 is composed of a roller 54. Delay angle adjustment device 4
4, the roller 54 and the spring 56 press the retard angle side, and the link type return mechanism 60 pushes the retard angle side toward the advance side. The link-type returning mechanism 60 is composed of a link 52 and a bridge 53 that pinch the roller 54 from above and below, and immediately after the top 17b of the cam crest 17a of the intake cam 17 passes through the bridge 53, the bridge 53 is attached to the link 52. From the tapered shape of the phantom diagram to the expanded shape of the solid diagram, the roller 54 resists the spring 56 by the thrust of the tapered surface formed by the bridge 53 and the link 52. Push it to the advance side, and follower 22
To lower the intake valve. The retard adjustment device 34 is composed of a triangular hole member 59 that can be adjusted in the vertical direction, and receives the movement of the roller 54 toward the advance side by the retard adjustment oblique side 59a. The retardation of the intake valve closing timing increases as it approaches the rising position in the figure.

<Problems to be Solved by the Invention> In the above-mentioned conventional example, there is a problem that an error occurs in the control of the retard angle of the intake valve closing timing.

That is, as the bridge 53 inclines in a divergent shape, the thrust force that pushes the roller 54 toward the advance side gradually increases, and the roller 54 is retarded from the time when the thrust force becomes stronger than the tension of the spring 56. Push it to the hypotenuse 59a.

Therefore, an error in the tension of the spring 56 appears as an error in the retard angle of the intake valve closing timing. That is, when the tension of the spring 56 is too strong, the movement of the roller 54 is delayed and the retard angle becomes too large. On the contrary, when the tension is too weak, the roller 54 moves quickly and the retard angle becomes too small.

Also, when the frictional resistance between the roller 54 and the bridge 53 and the link 52 is too large, the movement of the roller 54 is delayed and the retard angle becomes too large. Conversely, when the frictional resistance is too small, the retard angle becomes too small. .

Furthermore, as the engine speed increases, the moving speed of the roller 54 with respect to the angular speed of the intake cam 17 decreases,
The retard angle becomes too large. Therefore, it cannot be applied to high-speed engine rotation.

Moreover, since the timing of the intake valve cannot be controlled with high precision, when implemented in a multi-cylinder engine, the valve closing timing of each cylinder becomes uneven. Therefore, there is a problem in that the intake efficiency of each cylinder is different and the output is unbalanced, resulting in a large engine vibration and a decrease in output.

The present invention has been proposed in view of the above problems, and in a multi-cylinder engine, the intake valve closing timing of each cylinder is controlled with high accuracy in accordance with the engine speed to improve the intake charging efficiency and improve the engine output. The purpose is to be able to.

<Means for Solving the Problems> In order to achieve the above-mentioned object, the present invention is directed to, for example, as shown in FIG. 1 to FIG.
9 has a structure that works in synchronism with the intake cam 18, and is configured such that the retard cam 39 constrains the retard actuation body 20 and forcibly drives it, and each retard actuation body 20 has a common intermediate transmission. It is characterized in that it is configured so as to be interlockingly connected to one retard angle adjusting device 34 via a mechanism 36.

<Operation> With the above-described configuration, when the engine rotates, the follower 22 is pushed up by the intake cam 18 via the retarder 20.

Then, since the retarding body 20 is accompanied by the retarding cam 39 in the circumferential direction of the intake cam 18 by the retarding swing distance corresponding to the engine rotation speed, the follower 22 is pushed up by the intake cam 18. The state is maintained, and the intake valve closing timing is greatly retarded as the rotation speed becomes higher.

At this time, since the retard angle actuator 20 provided in each cylinder 7 is controlled by the common retard angle adjuster 34, the same retard angle swing distance is controlled.
The retarding swing distance of each retarding body 20 is controlled to be equal, and the retarding timing of the intake valve 10 of each cylinder 7 can be controlled with high accuracy.

<Examples> Examples of the present invention will be described below with reference to the drawings.

FIG. 1 is a schematic perspective view showing a valve mechanism of a 4-valve direct injection type 3-cylinder diesel engine in which two intake valves and two exhaust valves are provided in one cylinder, and FIG. 2 is a valve mechanism of the intake valve. FIG. 3 is a vertical sectional front view of the portion, and FIG.
FIG. 4 is a cross-sectional plan view of the valve mechanism and the retard angle drive unit.

In the drawings, reference numeral 1 indicates the entire engine, and the engine 1 includes a cylinder block 3 above a crankcase 2.
Is integrally formed, and the cylinder head 4 and the head cover 5 are sequentially placed and fixed above the cylinder block 3 to form the engine body 6.

A piston 8 is slidably housed in the cylinder 7 of the cylinder block 3, and a combustion chamber 9 is formed above the piston 8 and below the cylinder head 4.

The combustion chamber 9 has an intake passage 1 formed in the cylinder head 4 by two intake ports 11 whose opening is controlled by an intake valve 10.
2, and an exhaust path (not shown) communicates with an exhaust port 14 whose opening and closing is controlled by an exhaust valve 13.

The intake valve operating device 15 that drives the intake valve 10 is driven by the intake cam shaft 17 that is rotationally driven by the gear electric device 16 and the intake cam 18 of the intake cam shaft 17 that is pushed up by the retarding body 20. It includes a tappet (follower) 21, a push rod 22 that transmits the movement of the tappet 21, and a rocker arm 23 that is swung by the push rod 22.

A fuel injection cam 24 is formed on the intake cam shaft 17 on which the intake cam 18 is formed.

As shown in FIG. 1, the gear transmission 16 transmits the rotation of the clang gear 25 projectingly formed on the front surface of the engine body 6 to an intake cam gear 27 and an exhaust cam gear 28 arranged on the left and right via an idle gear 26, Intake cam gear 2
7 and the exhaust cam gear 28 are rotated at a deceleration of 1/2 with respect to the rotation of the crank gear 25.

Further, a booster pump 29 that discharges pressure oil proportional to the rotation speed of the engine 1 is attached to the front surface of the intake cam gear 27, and below the intake cam gear 27, the rotation speed of the engine 1 and the set rotation speed are set. A metering unit 31 is provided to meter a proportionate amount of fuel and supply it to the unit injector 30.

The drive device 22 that drives the retarding body 20 includes a booster pump (control drive device) 29 and a booster cylinder (delay adjusting device) 34 that supplies pressure oil discharged from the booster pump 29 through an oil passage 33. , A control shaft (intermediate transmission mechanism) 36 rotated by the roller 35 of the booster cylinder 34, and the retardation actuating body 20 provided in each cylinder by the rotation of the control shaft 36.
Retard adjustment device (retard drive device) for controlling the retard swing amount of
Consists of.

The retarding body 20 and the retarding adjuster 44 are configured as shown in FIGS. 5A and 5B to 10A and B.

That is, in the intake cam shaft portion corresponding to each cylinder 7, as shown in FIGS. 5A and 5B, a pair of intake cams 18 are formed in the middle portion between the bearing metal 38 and the fuel injection cam 24. A retard cam 39 eccentric from the axis P of the intake cam shaft 17 is formed between the intake cam 18 and the fuel injection cam 24 and between the intake cam 18 and the bearing metal 38.

Next, the U-shaped guide member 40 shown in FIGS. 6A and 6B is fitted between the intake cams 18 of the intake camshaft 17, and the U-shaped guide member 40 is inserted between the intake cams 18 of FIGS.
A gate-shaped sliding member 41 shown by B is vertically inserted into the slit 42 of the guide member 40 to form a retard angle operation portion 43 shown in FIGS. 8A and 8B.

The retarded angle actuating portion 43 formed in this manner can rotate about the intake cam shaft, and the wing-shaped retarded angle actuating body 20 formed above the sliding member 41 contacts the intake cam 18. The sliding member 41 is pushed up by the intake cam 18.

A retard adjustment device 44 for controlling the amount of retard swing of the retard actuator 20.
As shown in FIGS. 9A and 9B, is formed in a U shape in a front view, the left end portion is connected by the input member 45, and the right end portion is connected by the limiting member 46 to form a rectangular frame shape in plan view. Has been formed. When the retard angle adjuster 44 formed in this manner is externally fitted to the retard angle operation portion 43 (see FIGS. 10A and 10B) and the lower end portion of the guide member 40 is pressed counterclockwise by the return spring 47, the guide member The contact portion 48 protruding from the right end of 40 contacts the limiting member 46, and the retard angle actuating portion 43 is restrained by the retard angle adjuster 44. Further, the sliding contact surface 49 formed on the inner surface of the retard angle adjuster 44 contacts the retard cam 39 of the intake cam shaft 17.

When the control shaft 36 is rotated by the booster cylinder 34, the retarding body 20 is moved forward and backward by the connecting shaft 50 connected to the input member 45 of the retarder 44 as shown in FIG. The contact timing between the sliding contact surface 49 of the retard angle adjuster 44 and the eccentric cam 39 is adjusted, and the retard swing amount is controlled.

The operation of the intake valve closing timing retarding device configured as described above will be described below.

First, when the engine 1 rotates, the intake cam shaft 17 rotates, the tappet 21 is pushed up by the intake cam 18 via the retarding body 20, and the intake valve 10 is pushed down via the push rod 22 and the rocker arm 23. The intake port 11 is opened. When the intake port 11 is opened, the piston 8 descends to suck air into the combustion chamber 9 from the intake passage 12.

Next, when the top of the intake cam 18 passes the retarding body 20, the retarding body 20 also descends along the cam surface of the intake cam 18, and the intake valve via the tappet 21, the push rod 22, and the rocker arm 23. 10 rises, the valve is closed and intake is stopped.

At this time, when the rotational speed of the engine 1 is low, the pressure of the pressure oil from the pusher pump 29 is low, and the expansion of the booster cylinder 34 for rotating the control shaft 36 is small. The amount of protrusion of the pushing connecting shaft 50 is small, the sliding contact surface 49 of the retard angle adjuster 44 is brought into contact with the retard angle cam 39 near the apex thereof, and the retard angle adjuster 44 hardly moves. When the retard angle adjuster 44 does not swing in this way,
As shown in FIG. 12A, the tappet 21 has the intake cam 18
It goes up and down along the cam surface of.

Then, when the engine 1 becomes high speed, the pressure of the pressure oil from the booster pump 29 increases accordingly, so that the input member 45 of the retard angle adjuster 44 is largely pushed to the right by the connecting shaft 50. .

When the input member 45 of the retard angle adjuster 44 is pushed in greatly,
The sliding contact surface 49 abuts the retard cam 39 earlier, and the retard cam 39 that is interlocked with the intake cam 18 causes the retard adjuster 44 to swing greatly.

Thus, when the retard angle adjuster 44 is swung by the retard angle cam 39, the limiting member 46 of the retard angle adjuster 44 pushes down the contact portion 48 of the guide member 41, and the retard angle actuation body 20 is provided. The retard angle actuating portion 43 is slid in the circumferential direction of the intake cam 18 against the return spring 47 so that the retard angle actuating body 20 is moved toward the intake cam 1.
Since it swings in the state of being lifted by 8, the closing timing of the intake valve 10 is retarded by that amount as shown in FIG. 12B, and the intake charging efficiency at high speed is improved.

In the above embodiment, the retard angle adjuster 44 for setting the retard angle swing amount of the retard angle operation portion 43 is configured to be driven by the retard angle cam 39 formed on the intake cam shaft 17. 11, a retard cam 39 is provided separately from the intake cam shaft 17 and is linked to the intake cam 18, and the retard cam 18 swings the retard adjuster 44. May be controlled. In this case, the operating direction of the connector 50 that pushes and pulls the input member 45 of the retard angle adjuster 44 is controlled so as to be pulled leftward in the drawing during high-speed operation, contrary to the above embodiment.

In addition, although the engine for carrying out the present invention is the push rod type engine in the above embodiment, it goes without saying that it may be an overhead cam type engine. In this case, the retarding body is provided so as to act on the upper end portion of the intake valve directly or via the rocker arm.

Further, the delay angle adjusting device for operating the intermediate transmission mechanism may be provided with a manual lever instead of the booster cylinder, and the manual lever may be manually operated.

<Effects of the Invention> The present invention has the following effects because it is configured and operates as described above.

That is, the intake cam and the follower (tuppet) driven up and down by the intake cam.
The retardation actuation body interposed between and is controlled by the retardation drive while being restrained by the retardation drive device.

As a result, the valve closing timing of the intake valve can be always controlled with high accuracy in accordance with the rotation speed of the intake valve.

Further, since the retard angle swing amount of the retard angle actuator is performed by one retard angle adjuster via the intermediate transmission mechanism, the retard angle swing amount of the retard angle actuator provided in each cylinder of the multi-cylinder engine is adjusted. You can eliminate the uneven intake valve closing timing by adjusting to the character. As a result, engine vibration due to imbalance of intake air in each cylinder can be eliminated and the engine output can be improved.

[Brief description of drawings]

1 to 12 show an embodiment of the present invention, FIGS. 1 to 12 show an embodiment of the present invention, and FIG. 1 is a schematic of a valve operating mechanism of a 4-valve direct injection diesel engine. FIG. 3 is a perspective view, and FIG. 2 is a vertical cross-sectional front view of the valve mechanism of the intake valve.
FIG. 4 is a vertical sectional front view of the booster cylinder portion, FIG. 4 is a cross-sectional plan view of the booster cylinder portion, FIG. 5A is a vertical sectional front view of the intake cam shaft, FIG. 5B is its plan view, and FIG. 6A is a guide. Front view of the member, FIG. 6B is its plan view, FIG. 7A is a front view of the sliding member, FIG. 7B is its plan view, and FIG. 8A is formed by attaching the sliding member to the guide member. 8B is a plan view thereof, FIG. 9A is a front view of the retard control device, FIG. 9B is a plan view thereof, and FIG. 10A is a retard operation unit. FIG. 10B is a front view for explaining the operation of the retard angle drive unit, and FIG. 12 is a front view for explaining the action of the retard angle drive device, and FIG. FIG. 13 is a graph showing a relationship, and FIG. 13 is a front view of a main part of a conventional example. 1 ... Multi-cylinder internal combustion engine (engine), 7 ... Cylinder, 10 ... Intake valve, 15 ... Intake valve operating system, 18 ... Intake cam, 20 ... Retarder, 21 ... Follower ( Tappet), 29 ... Control drive device (booster pump), 34 ... Delay angle adjusting device (booster cylinder), 36 ... Intermediate transmission mechanism, 39 ... Delay cam, 44 ... Delay drive device.

Claims (3)

[Claims] 1. A retarder 2 between an intake cam 18 and a follower 21 of each cylinder 7 of an intake valve operating system 15 of a multi-cylinder internal combustion engine 1.
0 is interposed between the retard angle actuation bodies 20 and the retard angle drive devices 44.
Is configured to retard the closing timing of the intake valve 10 by reciprocating along the circumferential direction of the intake cam 18 in synchronism with the intake cam 18. In the intake valve closing timing retarding device of the intake valve operating system of the internal combustion engine, which is configured to be adjustable by the retard adjusting device 34,
4 has a structure in which the retard cam 39 is interlocked with the intake cam 18 in synchronization with the retard cam 39. The retard cam 39 constrains the retard actuation body 20 to forcibly drive the retard actuation body 20. Via a common intermediate transmission mechanism 36
Intake valve closing timing retarding device for an intake valve operating device of an internal combustion engine, characterized in that 2. An intake valve operating system for an internal combustion engine according to claim 1, wherein the retard control device 34 is controlled and driven by a control drive device 29 in accordance with the rotational speed of the engine. Valve closing timing retarder 3. An intake valve closing timing retarding device for an intake valve operating system for an internal combustion engine according to claim 1, wherein the retard adjusting device 34 is configured to be manually adjustable.