JPH0656091B2 - 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 relates to an intake valve operating system for an internal combustion engine, by delaying the closing timing of the intake valve when the engine is rotating at high speed or under high load, This is a technique for controlling the retardation of the intake valve closing timing with high accuracy in a device that improves efficiency.

<Prior Art> Among the intake valve closing timing retarding devices, the present invention has a prerequisite structure, for example, as shown in FIG. 1 to FIG. 13 or FIG. 14, of the intake valve operating device 15 of the internal combustion engine 1. Intake cam 17
And the follower 20 with the retarder 19 interposed therebetween, and the retarder 19 is reciprocally driven in synchronization with the intake cam 17 in the circumferential direction of the intake cam 17 by the retarder drive device 46. Intake valve 1
The valve closing timing of 0 is configured to be retarded, and the retarder 19
Of the type having a structure in which the retard angle drive distance can be adjusted by the retard angle adjuster 34.

As a conventional technique in this format, Japanese Patent Laid-Open No. 59-939
There is one disclosed in Japanese Patent Publication No. 09, which is configured as follows in the above premise structure as shown in FIG.

That is, the retarder 19 comprises the roller 64. The retard drive device 46 pushes the roller 64 toward the retard side with the spring 63 and pushes it back toward the advance side with the link type return mechanism 69. The link-type return mechanism 69 includes the roller 64.
It is composed of a link 61 and a bridge 62 that pinch each other from above and below.
Immediately after passing 2, bridge 62 to link 61
Is changed from the tapered shape of the phantom diagram to the expanded shape of the solid diagram, and the roller 64 is resisted against the spring 63 by the thrust of the tapered surface formed by the bridge 62 and the link 61. And pushes it toward the advance side, thereby lowering the follower 20 and closing the intake valve. Delay angle adjustment device 3
Reference numeral 4 denotes a triangular hole member 68 which can be adjusted in the vertical direction, and the retard angle adjusting slant 68a is used to receive the movement of the roller 64 toward the advance side, and to raise the virtual diagram from the lowered position in the solid diagram. The closer to the position, the larger the retardation of the intake valve closing timing.

<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 62 inclines in a divergent manner, the thrust force that pushes the roller 64 toward the advance side gradually increases, and the roller 64 is retarded when the thrust force becomes stronger than the tension of the spring 63. Push it to the hypotenuse 68a.

Therefore, an error in the tension of the spring 63 appears as an error in retarding the intake valve closing timing. That is, when the tension of the spring 63 is too strong, the movement of the roller 64 is delayed and the retard angle becomes too large. On the contrary, when the tension is too weak, the roller 64 moves quickly and the retard angle becomes too small.

Further, when the frictional resistance between the roller 64 and the bridge 62 or the link 61 is too large, the movement of the roller 64 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 intake cam 17
Since the moving speed of the roller 64 becomes slower than the angular speed of, the retard angle becomes too large. Therefore, it cannot be applied to high-speed engine rotation.

An object of the present invention is to make it possible to control the retardation of the intake valve closing timing with high accuracy and, moreover, to sufficiently adapt it to the high speed rotation of the engine.

<Means for Solving Problems> In order to achieve the above-mentioned object, the present invention provides, for example, FIG.
As shown in FIG. 13, the retard drive device 46 has at least a retard cam 40 and a return means 49, and has a structure in which the retard cam 40 interlocks with the intake cam 17 in synchronization. Is configured to be moved back to the advance side by the return means 49 and to be forcedly driven to the retard side by the retard cam 40.

<Operation> The present invention operates as follows.

The cam crest portion of the intake cam 17 pushes up the follower 20 via the retarder 19 so that the intake valve 10 is opened.

The retarding body 19 is returned to the reference position by the returning means 49 at the beginning of the valve closing timing, and is forcibly swung to the retarding position by the retarding cam 40 until the end thereof. . This swing angle θ becomes the retard amount of the intake valve closing timing.

When the retard adjustment device 34 is adjusted to the retard side, the retard cam 40
The amount of retard angle θ increases as the swing angle for swinging the retard angle actuator 19 increases, and the amount of retard angle θ decreases when adjusted toward the advance side.

<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.
The exhaust valve 13 is connected to the exhaust passage (not shown).
An exhaust port 14 controlled to open and close by is connected.

The valve operating device 15 that drives the intake valve 10 includes a crank gear 2
5, an intake cam shaft 23 rotatably driven via a gear transmission 16, an intake cam 17 provided on the intake cam shaft 23, and a tappet (which is driven to be pushed up via a retarding member 19 of a retarding drive device 46). (Following part) 20, a push rod 21 for transmitting the movement of the tappet 20, and a rocker arm 22 rocked by the push rod 21.

A fuel injection cam 24 is formed on the intake cam shaft 23 on which the intake cam 17 is formed.

As shown in FIG. 1, the gear transmission 16 transmits the rotation of the crank gear 25 to the intake cam gear 27 and the exhaust cam gear 28, which are arranged on the left and right, through the idle gear 26 on the front surface of the engine body 6, and 27 and the exhaust cam gear 28 are 1 with respect to the rotation of the crank gear 25.
/ 2 Decelerates to rotate.

A booster pump (control drive device) 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 the rotation speed of the engine 1 is below the intake cam gear 27. Further, a metering unit 31 for metering the fuel corresponding to the set rotation speed and supplying it to the unit injector 30 is provided.

A retard drive device 46 that drives the retard actuating body 19 includes a booster pump (control drive device) 29 and a booster cylinder (delay adjustment device that supplies pressure oil discharged from the booster pump 29 through an oil passage 33). ) 34, booster cylinder 3
Control shaft 36 and control shaft 36 rotated by the rod 35 of No. 4
And a retard angle adjuster (retard angle drive device) 46 that controls the retard angle swing amount of the retard angle actuator 19 by the rotation of.

Further, the retard angle actuation body 19 and the retard angle adjuster 46 are configured as shown in FIGS. 5A to 5B to 10A and 10B.

That is, as shown in FIGS. 5A and 5B, in the portion of the intake cam shaft 23 corresponding to each cylinder 7, a pair of intake cams 17 and 17 are provided in the middle portion between the bearing metal 39 and the fuel injection cam 24.
17, the intake cam 17 and the fuel injection cam 24
Between the intake cam 17 and the bearing metal 39, and the retard cam 4 eccentric from the axis P of the intake cam shaft 23.
0 is formed.

Next, a U-shaped guide member 41 shown in FIGS. 6A and 6B is loosely fitted between the intake cams 17 of the intake camshaft 23, and the U-shaped guide member 41 is inserted between the intake cams 17 of the intake camshaft 23.
The gate-shaped sliding member 42 shown in B is vertically inserted into the slit 43 of the guide member 41 to form the retarding angle operation portion 44 shown in FIGS.

The retarding portion 44 formed in this way can rotate around the intake cam 23, and the wing-shaped retarding member 19 formed above the sliding member 42 contacts the intake cam 17. The sliding member 42 is pushed up by the intake cam 17.

A retard adjustment device 46 for controlling the amount of retard swing of the retard actuator 19
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 47, and the right end portion is connected by the limiting member 48 to form a rectangular frame shape in plan view. Has been formed. The retard angle adjuster 46 formed in this manner is externally fitted to the retard angle operation portion 44 (see FIGS. 10A and 10B), and the guide member 41 is provided.
When the lower end portion of the guide member 41 is pressed counterclockwise by the return spring returning means 49 (see FIG. 11), the contact portion 50 protruding from the right end portion of the guide member 41 contacts the limiting member 48 and the retard angle operation portion. 44 is received by the retard angle adjuster 46. In addition, the sliding contact surface 51 formed on the inner surface of the retard angle adjuster 46 is the intake camshaft 2
Abut the retard cam 40 of No. 3.

When the control shaft 36 is rotated by the above-mentioned booster cylinder 34, the retard angle actuating body 19 adjusts the advancing / retreating of the connecting shaft 52 connected to the input member 47 of the retard angle adjuster 46 as shown in FIG. The contact timing between the sliding contact surface 51 of the retard angle adjuster 46 and the eccentric cam 40 is adjusted, and the retard angle 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 23 rotates, the tappet 20 is pushed up by the intake cam 17 via the retarding body 19, and the intake valve 10 is pushed down via the push rod 21 and the rocker arm 22. , Open the intake port 11. When the intake port 11 is opened, the piston 8 descends to suck air into the combustion chamber 9 from the intake passage 11.

Next, when the top of the intake cam 17 passes the retarding body 19, the retarding body 19 also descends along the cam surface of the intake cam 17, and the intake valve 10 is pushed through the tappet 20, the push rod 21, and the rocker arm 22. Rises, the valve is closed and intake is stopped.

At this time, when the rotation 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 24 for rotating the control shaft 36 is small. The pushing amount of the connecting shaft 52 to be pushed is small, the sliding contact surface 51 of the retard angle adjuster 46 contacts near the apex of the retard angle cam 40, and the retard angle adjuster 46 hardly moves. When the retard angle adjuster 46 does not swing in this way,
As shown by the curve A in FIG. 12, the tappet 20 moves up and down along the cam surface of the intake cam 17.

Then, when the engine 1 becomes high speed, the pressure of the pressure oil from the booster pump 29 also increases accordingly, so that the input member 47 of the retard angle adjuster 46 is largely pushed rightward by the connecting shaft 52. .

When the input member 47 of the retard angle adjuster 46 is pushed largely,
The sliding contact surface 51 abuts the retard cam 40 earlier, and the retard cam 40 interlocked with the intake cam 17 causes the retard adjuster 46 to swing greatly.

Thus, when the retard angle adjuster 46 is swung by the retard angle cam 40, the restricting member 48 of the retard angle adjuster 46 pushes down the contact portion 50 of the guide member 41, and the retard angle actuation body 19 is provided. The retard angle actuating portion 44 is slid in the circumferential direction of the intake cam 17 against the return spring 49 so that the retard angle actuating member 19 is moved to the intake cam 1 side.
Since it swings in the state of being lifted by 7, the closing timing of the intake valve 10 is retarded by that amount as shown by the curve B in FIG.
The charging efficiency of intake air at high speed is improved.

In the above embodiment, the retard angle adjuster 46 provided for each cylinder 7 is retarded by the single booster cylinder 34 via the control shaft 36. However, the booster cylinder 34 is provided for each cylinder 7. This booster cylinder 34
The control shaft 36 and the connecting shaft 52 of the above-described embodiment may be omitted by directly controlling the retard adjustment device 46 with.

Further, in the above-mentioned embodiment, the retard angle adjuster 46 for setting the retard angle swing amount of the retard angle operation portion 44 is configured to be driven by the retard angle cam 40 formed on the intake cam shaft 23. As shown in the phantom diagram in FIG. 11, the retard cam 40 is provided separately from the intake cam shaft 23 and is linked to the intake cam 17,
The retard cam 40 may control the swing drive of the retard adjuster 46. In this case, the operation direction of the connector 52 for pushing and pulling the input member 47 of the retard angle adjuster 46 is controlled so as to be pulled leftward in the drawing during high speed operation, contrary to the above embodiment.

Further, as shown in FIG. 13, the retard cam 40 is provided separately from the intake cam shaft 23 and is interlocked with the intake cam shaft 17, and the retard cam 40 is formed by the groove cam 55. Between the knot roller 51 and the retard angle actuator 19, the retard angle actuator 1
The intake valve closing timing retarding device may be configured by providing the retard adjusting device 46 for setting the retard amount of 9.

In addition, as a matter of course, the intake valve operating device may be changed from the push rod interposing type to the overhead cam type, and the retard angle adjusting device 34 may be manually adjusted.

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

In other words, the retard cam forcibly drives the retard actuating body accurately and accurately without being affected by the returning force of the returning means, so that the returning force of the returning means becomes too strong or too weak. In this case, or even if an error occurs in the drive resistance of the retard angle actuator, the retard angle actuator can be precisely retarded to the value adjusted by the retard angle adjuster.

Moreover, no matter how fast the engine speed increases, the retard cam always forcibly and accurately drives the retard actuating member at a precise timing, so that the engine can be sufficiently adapted even when the engine speed is increased.

[Brief description of drawings]

1 to 13 show an embodiment of the present invention, FIG. 1 is a schematic perspective view of a valve operating mechanism of a 4-valve direct injection diesel engine, and FIG. 2 is a longitudinal section of a valve operating mechanism of an intake valve. Front view, third
FIG. 4 is a vertical sectional front view of the booster cylinder portion, FIG. 4 is a cross sectional plan view of the valve operating mechanism and the booster cylinder portion, FIG. 5A is a vertical sectional front view of the intake cam shaft, and FIG. 5B is its plan view.
FIG. A is a front view of the guide 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 a sliding member on the guide member. FIG. 8B is a front view of the retarding angle adjusting portion formed by attaching the FIG. 9A, FIG. 9A is a front view of the retarding angle adjuster, FIG. 9B is its plan view, and FIG. FIG. 10B is a front view in which the retard angle adjuster is attached to the working portion.
Is a plan view thereof, FIG. 11 is a front view for explaining the action of the valve closing timing retarding device, FIG. 12 is a graph showing the relationship between the intake valve opening amount and the piston head, and FIG. FIG. 11 is a view corresponding to FIG. 11 showing an embodiment, and FIG. 14 is a front view of a main part of a conventional example. DESCRIPTION OF SYMBOLS 1 ... Internal combustion engine (engine), 10 ... Intake valve, 15 ... Intake valve operating device, 17 ... Intake cam, 19 ... Retarder actuating body, 20 ... Follower (tappet), 29 ... Control drive device (booster pump), 34 ... Retard angle adjusting device (booster cylinder), 40 ... Retard angle cam, 46 ... Retard angle drive device (retard angle adjuster), 49 ... Return means (return spring).

Claims (3)

[Claims] 1. A retarding body (19) is interposed between an intake cam (17) of an intake valve gear (15) of an internal combustion engine (1) and a follower (20),
The retard angle actuator (19) is reciprocally driven in the circumferential direction of the intake cam (17) by the retard angle drive device (46) in synchronization with the intake cam (17) to close the intake valve (10). Is configured to retard the intake valve closing timing of the internal combustion engine intake valve operating device by adjusting the retarding drive distance of the retarding effector (19) by the retarding adjuster (34). In the retard drive (46), at least the retard cam (40) and the return means
(49) and has a structure in which the retard cam (40) is interlocked in synchronization with the intake cam (17), and the retard actuating body (19) is moved back to the advance side by the returning means (49). In addition, the intake valve closing timing retarding device for the intake valve operating system of the internal combustion engine is characterized in that the retarding cam (40) is configured to forcibly drive to the retarding side. 2. The intake motion of an internal combustion engine according to claim 1, wherein the retard angle adjusting device (34) is controlled and driven by a control drive device (29) in accordance with the rotational speed of the engine. Intake valve closing timing retarder for valve device. 3. An intake valve closing timing retarding device for an intake valve operating system of an internal combustion engine according to claim 1, wherein the retard adjusting device (34) is manually adjustable.