JPH0684730B2 - Internal combustion engine - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION A. Purpose of the Invention (1) Industrial Utilization Technology The present invention relates to a valve operating characteristic changing mechanism capable of switching the operating characteristics of an intake valve or an exhaust valve to a plurality of types, and a function depending on the load of the engine. The present invention relates to an internal combustion engine including a control means for switching the valve operating characteristic changing mechanism.

(2) Related Art Conventionally, an internal combustion engine in which the operating characteristics of the intake valve or the exhaust valve are switched to a plurality is known, for example, from JP-A-61-19911.

(3) Problems to be Solved by the Invention By the way, the valve operation characteristic changing mechanism changes the opening / closing operation characteristics of the intake valve or the exhaust valve stepwise according to the load of the engine, so that an appropriate valve according to the load is obtained. The operating characteristics are to reduce fuel consumption and improve the output.However, since there is a difference in output torque between the operating characteristics of the intake valve or the exhaust valve, there is a difference due to the torque difference during the switching operation of the valve operating characteristic changing mechanism. You may feel a shock.

The present invention has been made in view of the above circumstances, and an object of the present invention is to provide an internal combustion engine that is capable of reducing shock as much as possible during a switching operation of a valve operating characteristic changing mechanism and improving operational performance.

B. Configuration of the Invention (1) Means for Solving the Problems In order to achieve the above object, according to the present invention, a throttle valve driving means is connected to a throttle valve, and a valve operating characteristic changing mechanism is connected to a control means. A plurality of different throttle opening characteristics with respect to the amount of depression of the accelerator pedal are set respectively corresponding to the plurality of valve operation characteristics that are switched by the throttle opening degree according to the switching operation of the valve operation characteristic changing mechanism. It is characterized in that the control means and the throttle valve driving means are connected so that the characteristics are switched and changed to those corresponding to the valve operating characteristics after the switching.

(2) Operation According to the above configuration, the throttle valve drive means changes the throttle opening characteristic with respect to the depression amount of the accelerator pedal to the valve operation characteristic after switching in response to the switching operation of the valve operation characteristic changing mechanism. It is changed to open and close the throttle valve. As a result, the relationship between the accelerator pedal depression amount and the engine output torque can be made substantially linear,
The output torque difference during the switching operation of the valve operating characteristic changing mechanism can be minimized.

(3) Embodiment Hereinafter, one embodiment of the present invention will be described with reference to the drawings. First, in FIG. 1, FIG. 2 and FIG. 3, an intake valve 1 provided in an engine main body E is a crankshaft of an engine. 1 /
A low speed cam 3, a medium speed cam 4 and a high speed cam 5 that are integrally provided on a cam shaft 2 that is rotationally driven at a reduction ratio of 2, and a rocker shaft 6 that is pivotally supported by a rocker shaft 6 that is parallel to the cam shaft 2. 1, 2nd and 3rd rocker arms 7, 8, 9 and valve actuation characteristic changing mechanism 1 provided between 1st and 2nd rocker arms 7 and 8 and between 2nd and 3rd rocker arms 8 and 9
It is opened and closed by the action of 0a and 10b.

The cam shaft 2 is rotatably arranged above the engine body E, and the middle speed cam 4, the low speed cam 3 and the high speed cam 5 are integrated with the cam shaft 2 so as to be adjacent in the axial direction. The low speed cam 3 is formed to have a shape corresponding to a low load operation of the engine, the medium speed cam 4 is formed to have a shape corresponding to a medium load operation of the engine, and the high speed cam 5 is formed to a high load of the engine. It is formed into a shape suitable for driving.

The rocker shaft 6 is fixedly arranged below the cam shaft 2. This rocker shaft 6 has a medium speed cam 4
A first rocker arm 7 having a cam slipper 11 slidably contacting the upper part, a second rocker arm 8 having a cam slipper 12 slidably contacting the low speed cam 3 at the upper part, and a cam slipper 13 slidably contacting the high speed cam 5 at the upper part Third rocker arm 9
Are pivoted on both sides of the second rocker arm 8 so that the first and third rocker arms 7 and 9 are adjacent to each other.

The intake valve 1 is interlocked and connected to the second rocker arm 8. That is, the intake valve 1 is biased in the valve closing direction, that is, upward by the valve spring 15 interposed between the flange portion 14 provided at the upper end of the intake valve 1 and the engine body E, and the second rocker arm 8
A tappet screw 16 abutting on the upper end of the intake valve 1 is screwed to the tip of the so as to be able to move forward and backward.

The cam rocker 11 of the first rocker arm 7 is provided with the elastic body urging means 17 provided between the first rocker arm 7 and the engine body E so that the cam 4 for the medium speed can move.
It is biased in the direction of sliding contact with. This bullet urging means 17 is
It is composed of a bottomed cylindrical lifter 18 whose closed end is in contact with the lower surface of the first rocker arm 7, and a lifter spring 19 interposed between the lifter 18 and the engine body E. It is slidably fitted in the provided bottomed hole 20.

An elastic urging means (not shown) similar to the elastic urging means 17 is also provided between the third rocker arm 9 and the engine body E, and the third rocker arm 9 also includes the first rocker arm 7. Similarly, the cam slipper 13 is constantly elastically urged upward, and is in sliding contact with the high speed cam 5.

Referring also to FIG. 4, the valve operating characteristic changing mechanism 10a is
A connecting pin movable between a position for connecting the first and second rocker arms 7 and 8 and a position for releasing the connected state.
22a and a stopper pin that regulates the movement of the connecting pin 22a
23a and a return spring 24 for urging the connecting pin 22a toward the disconnecting side.
have a and.

The second rocker arm 8 is provided with a bottomed first guide hole 25a that is open toward the first rocker arm 7 side and is parallel to the rocker shaft 6. The first guide hole 25a
A small diameter portion 27a is provided on the closed end side of the through a step portion 26a. A connecting pin 22a is slidably fitted in the first guide hole 25a, and a hydraulic chamber 28a is defined between the connecting pin 22a and the closed end of the first guide hole 25a.

Corresponding to the first guide hole 25a, a bottomed second guide hole 29a opened to the second rocker arm 8 side is bored in the first rocker arm 7 in parallel with the rocker shaft 6. A stopper 23a on the disk is slidably fitted in the hole 29a. A small diameter portion 31a is provided on the closed end side of the second guide hole 29a via a step portion 30a, and an insertion hole 32a coaxial with the small diameter portion 31a is formed at the closed end. Moreover, the stopper
The guide rod 33a provided coaxially and integrally with the 23a has an insertion hole 32a.
Is inserted into. Furthermore, the stopper 23a and the second guide hole 29a
A coil-shaped return spring 24a surrounding the guide rod 33a is interposed between the closed end and the closed end.

The axial length of the connecting pin 22a is such that the other end is located between the first and second rocker arms 7 and 8 when one end contacts the stepped portion 26a, and the stopper 23a is provided on the regulation stepped portion 30a. It is set so that one end remains in the first guide hole 25a when it comes into contact with the second guide hole 29a until it abuts.

On the other hand, the inside of the rocker shaft 6 is a partition wall that extends in the axial direction.
It is divided into two oil passages 34a and 34b by 37. Further, the rocker shaft 6 has a communication hole 35a communicating with one oil passage 34a.
And a communication hole 35b communicating with the other oil passage 34b are formed at positions axially separated from each other, and communicate with a communication passage 36a communicating with the communication hole 35a regardless of the rocking state of the second rocker arm 8. Hole 35
A communication passage 36b communicating with b is formed in the second rocker arm 8. Moreover, the communication passage 36a communicates with the hydraulic chamber 28a.

The valve operating characteristic changing mechanism 10b provided between the second and third rocker arms 8 and 9 has basically the same configuration as the valve operating characteristic changing mechanism 10a. The corresponding portion is only shown by adding the subscript b, and detailed description is omitted. The hydraulic chamber 28b of the valve operating characteristic changing mechanism 10b communicates with the oil passage 34b through the communication passage 36b and the communication hole 35b.

The oil passages 34a, 34b in the rocker shaft 6 are connected to the hydraulic pressure supply passage 41 communicating with the hydraulic pressure supply source 40 via three-way electromagnetic switching valves 42a, 42b, respectively. These three-way solenoid switching valves 42a, 42
b is a mode in which the oil passages 34a, 34b are communicated with the hydraulic pressure supply passage 41,
A mode in which the oil passages 34a and 34b are released to an oil tank (not shown) can be switched, and is controlled by the control means 43.

When the two-way electromagnetic switching valves 42a, 42b are in a state where the oil passages 34a, 34b are opened to the oil tank, the double valve operating characteristic changing mechanism 10
Since the hydraulic pressures in the hydraulic chambers 28a and 28b of a and 10b are released, the double valve actuation characteristic changing mechanisms 10a and 10b are in the decoupled state, and in this state, the intake valve 1 is rockably driven by the low speed cam 3. The intake valve 1 is opened and closed by a second rocker arm 8 which opens and closes, and the intake valve 1 is opened and closed at a timing and a lift amount according to the shape of the low speed cam 3. When one of the three-way electromagnetic switching valves 42a connects the oil passage 34a to the hydraulic pressure supply passage 41 and the other three-way electromagnetic switching valve 42b opens the oil passage 34b, the one valve operation characteristic changing mechanism 10a communicates. In contrast to this, the other valve operating characteristic changing mechanism 10b is in the disconnection state. Therefore, the second rocker arm 8 is connected to the first rocker arm 7, and the intake valve 1 is opened and closed by the first rocker arm 7 driven by the middle speed cam 4, and the timing and the timing corresponding to the shape of the middle speed cam 4 are set. It opens and closes depending on the lift amount. Furthermore, the one-way three-way solenoid valve 42a is connected to the oil passage 3
4a is opened and the other three-way solenoid valve 42b
When 4b is in communication with the hydraulic pressure supply passage 41, one valve operating characteristic changing mechanism 10a is in the disconnected state, while the other valve operating characteristic changing mechanism 10b is in the connected state.
Therefore, the second rocker arm 8 is connected to the third rocker arm 9, and the intake valve 1 is driven by the high speed cam 5 to the third rocker arm 3.
The rocker arm 9 causes the rocker arm 9 to open and close, and opens and closes at a timing and a lift amount according to the shape of the high speed cam 5.

The control means 43 uses the three-way electromagnetic switching valve according to the load of the engine.
42a and 42b are controlled, and in order to determine the load of the engine, the control means 43 includes a detector S1 for detecting the cooling water temperature of the engine, a detector S2 for detecting the engine speed, and an intake negative of the engine. A detector S3 that detects the pressure, a detector S4 that detects the throttle opening, and the like are connected. As a result, when it is determined that the engine has a low load, the control means causes the oil passages 34a, 34a
Release b to open the valve operating characteristic changing mechanisms 10a and 10b in a disengaged state to open and close the intake valve 1 at a timing and a lift amount according to the shape of the low speed cam 3 to switch between three-way electromagnetic switching.
When it is determined that the engine has a medium load by controlling 42a and 42b, only one oil passage 34a is communicated with the hydraulic pressure supply source 40 to bring the valve operating characteristic changing mechanism 10a into the connected state and the other valve operating characteristic. The change mechanism 10b is decoupled to control the three-way electromagnetic switching valves 42a and 42b to open and close the intake valve 1 at a timing and a lift amount according to the shape of the medium speed cam 4, and the engine has a high load. If it is determined that only the other oil passage 34b is in communication with the hydraulic pressure supply source 40 to bring the valve operation characteristic changing mechanism 10b into the connected state and the one valve operating characteristic changing mechanism 10a into the unconnected state, the intake valve 1
The three-way electromagnetic switching valves 42a, 42b are controlled so as to open and close at a timing and a lift amount according to the shape of the high speed cam 5.

By the way, the throttle valve 45 provided in the middle of the intake pipe 44 of the engine is opened and closed by the throttle valve drive means 46, and this throttle valve drive means 46 is also the control means.
Controlled by 43. That is, a detector S5 that detects the amount of depression of the accelerator pedal 47 is connected to the control means 43, and the control means 43 is responsive to an input signal from the detector S5.
Controls the operation of the throttle valve drive means 46. Moreover, as shown in FIG. 5, the control means 43 includes an accelerator pedal 47.
A map is set in which the relationship between the depression amount and the throttle opening is changed stepwise according to the load of the engine, and the opening of the throttle valve 45 is controlled according to this map.
That is, the throttle opening L in the low load state of the engine,
The throttle opening degree M in the medium load state of the engine and the throttle opening degree H in the high load state of the engine are linearly set with hysteresis when switching between them, and the control means 43 The three-way electromagnetic switching valves 42a, 42b are controlled according to the load of the engine to control the operation of the valve operation characteristic changing mechanisms 10a, 10b, and the operation of the throttle valve driving means 46 according to the control map shown in FIG. To do.

Next, the operation of this embodiment will be described. The engine output torque when the throttle valve 45 is fully opened is shown in FIG. 6 by controlling the operation of the valve operation characteristic changing mechanisms 10a and 10b according to the load of the engine. Like In FIG. 6, the curve H ₁ shows the engine high load, the curve M ₁ shows the engine medium load, and the curve L ₁ shows the engine low load.
The output torque also changes due to the change in the operating mode according to the engine load.

Thus, as shown in FIG. 5, the relationship between the throttle opening and the depression amount of the accelerator pedal 47 is set so as to change according to the engine load. By doing so, the engine output torque with respect to the throttle opening becomes as shown in FIG. In FIG. 7, a straight line H ₂ shows a high engine load, a straight line M ₂ shows a medium engine load, and a straight line L ₂ shows a low engine load. The output torque of the engine corresponding to the depression amount of the accelerator pedal 47 becomes linear in accordance with the change of the output torque characteristic of. Therefore, the valve operating characteristic changing mechanism 10a, 10b
By controlling the operation of the intake valve 1 according to the load of the engine, the output of the intake valve 1 can be improved and the fuel consumption can be reduced by adapting the operation mode of the intake valve 1 to the engine load. It is possible to improve the drivability by eliminating the step of the output torque during the switching operation, preventing the shock from occurring.

Although the valve operating device for the intake valve 1 has been described in the above embodiments, the present invention is also applicable to an exhaust valve operating device.

C. Effect of the Invention As described above, according to the present invention, the throttle valve drive means is connected to the throttle valve, and the control means corresponds to a plurality of valve operating characteristics switched by the valve operating characteristic changing mechanism. , A plurality of different throttle opening characteristics with respect to the accelerator pedal depression amount are set, and the throttle opening characteristics correspond to the valve operation characteristics after switching according to the switching operation of the valve operation characteristic changing mechanism. Since the control means and the throttle valve driving means are connected so as to be changed over, the throttle opening characteristic with respect to the accelerator pedal depression amount is changed after the switching according to the switching operation of the valve operation characteristic changing mechanism during engine operation. The valve operating characteristic can be automatically changed to a valve operating characteristic corresponding to the valve operating characteristic of the valve operating characteristic. Since the output torque difference during the switching operation of the switching mechanism can be minimized, the shock during the switching operation of the valve operating characteristic changing mechanism can be reduced as much as possible, and the operability of the internal combustion engine with the valve operating characteristic changing mechanism can be improved. Can greatly contribute to

[Brief description of drawings]

The drawings show an embodiment of the present invention. FIG. 1 is a plan view, FIG. 2 is a sectional view taken along line II-II of FIG. 1, and FIG.
Fig. 3 is a cross-sectional view taken along the line III-III, Fig. 4 is a view showing a cross section of the valve operation changing mechanism along the line IV-IV in Fig. 2 and a control circuit, and Fig. 5 is a graph showing the accelerator pedal depression amount and the throttle opening. FIG. 6 shows the relationship between the engine speed and the output torque, FIG. 7 shows the relationship between the throttle opening and the output torque, and FIG. 8 shows the accelerator pedal depression amount and the output torque. It is a figure which shows the relationship with. 1 ... Intake valve, 10a, 10b ... Valve operating characteristic changing mechanism, 43 ...
… Control means, 45 …… Throttle valve, 46 …… Throttle valve drive means, 47 …… Accelerator pedal

Claims (1)

[Claims] 1. A valve operating characteristic changing mechanism (10a, 10b) capable of switching the operating characteristics of an intake valve (1) or an exhaust valve to a plurality.
In an internal combustion engine including a control means (43) for switching and operating the valve operation characteristic changing mechanism (10a, 10b) according to the load of the engine, a throttle valve driving means (46) is connected to the throttle valve (45), The control means (43) includes an accelerator pedal (47) corresponding to each of a plurality of valve operating characteristics switched by the valve operating characteristic changing mechanism (10a, 10b).
A plurality of different throttle opening characteristics with respect to the depression amount of the valve operating characteristic changing mechanism (10a, 10
The control means (43) and the throttle valve driving means (46) so that the throttle opening characteristic is switched to a value corresponding to the valve operating characteristic after switching in accordance with the switching operation of b).
Internal combustion engine, characterized in that the spaces are connected.