JPH04301145A - Intake air quantity controller for engine - Google Patents

Abstract

PURPOSE:To secure the responsiveness and control precision by the use of a single motor, when the throttle valve of an engine is opening/closing-operated by the drive of an electric motor. CONSTITUTION:An intake air quantity controller far engine is equipped with a speed reduction mechanism C between an electric motor and a throttle valve B, and a reduction ratio varying means D which increases the reduction ratio which when the drive quantity of the motor is small, in comparison with the case where the drive quantity is large, and for example during the constant speed traveling control, the reduction ratio is increased.

Description

[Detailed description of the invention]

0001

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to an engine intake air amount control device in which an electric motor is used to open and close a throttle valve installed in an intake passage of the engine.

0002

[Prior Art] Conventionally, as an intake air amount control device for an engine, the mechanical link between the throttle valve of the intake system and the accelerator mechanism is eliminated, and the throttle valve is opened and closed by driving an electric motor, and its opening and closing characteristics are controlled. For example, a technology that increases the degree of freedom is disclosed in Japanese Patent Application Laid-Open No. 63-314.
It is known as seen in Japanese Patent No. 328. In addition, if an electronically controlled throttle valve is configured that adjusts the intake air amount of the engine by driving the throttle valve with an electric motor as described above, the intake air amount or This makes it possible to perform traction control that adjusts engine output.

On the other hand, constant speed driving control adjusts the engine output according to the deviation between the actual vehicle speed and the set value in order to maintain the vehicle speed at the set value. Volume control techniques are also commonly employed. The actuator for this constant speed running control is usually controlled by adjusting the accelerator opening.

0004

[Problems to be Solved by the Invention] However, when the throttle valve is opened and closed by an electric motor as described above, when changing the throttle opening based on various controls, it is difficult to adjust the target throttle opening. The problem is that it is difficult to achieve both responsiveness to reach the target opening and positioning accuracy to match the target opening.

That is, when installing a mechanism for opening and closing an electric motor such as a step motor in conjunction with a throttle valve, when it is desired to open and close the throttle valve suddenly during sudden acceleration or deceleration, etc. For example, it is preferable to increase the opening/closing speed by setting a large throttle angle for opening/closing in one step drive of the motor, thereby improving the responsiveness of the opening/closing operation to the target throttle opening. However, if you emphasize responsiveness and increase the opening/closing speed to increase the amount of movement in one step, for example when performing constant speed driving control, the set vehicle speed and actual vehicle speed will become close and the target throttle opening will be reduced. When the deviation of the actual throttle opening is small, the amount of change in the opening is large even in one step driving, and the positioning accuracy, that is, the control accuracy becomes low. On the other hand, if the amount of movement in one step is made small in order to improve control accuracy, the rate of change in throttle opening will be low and good responsiveness will not be obtained.

On the other hand, providing an electric motor and servo system that can provide both control response and control accuracy characteristics as described above requires high accuracy requirements for the electric motor, and the servo system is also complex and expensive. This makes it difficult to apply it to general engines. In addition, an electric motor that opens and closes the throttle valve with characteristics that emphasize responsiveness in response to accelerator operations, etc., and an electric motor that opens and closes the throttle valve with characteristics that emphasize control accuracy such as for constant speed driving control are separately installed. The installation also poses an obstacle to making the throttle drive mechanism more compact, and driving with a single electric motor is preferable.

SUMMARY OF THE INVENTION In view of the above circumstances, it is an object of the present invention to provide an engine intake air amount control device that achieves both control responsiveness and control accuracy using a compact mechanism.

[0008]

[Means for Solving the Problems] In order to achieve the above object, the intake air amount control device of the present invention, as shown in the basic configuration in FIG. B is interposed, and the throttle valve B
An electric motor M is connected to the throttle valve B via a speed reduction mechanism C, and the throttle valve B is opened and closed by driving the electric motor M. The electric motor M has an intake air amount control means F.
A control signal is output from the intake air amount control means F.
controls the amount of intake air by outputting a control signal for opening and closing the throttle valve B so that the amount of intake air corresponds to the operating state such as the accelerator opening, that is, the target throttle opening.

Further, between the electric motor M and the throttle valve B, there is installed a speed reduction mechanism C and a speed reduction ratio variable means D for changing the speed reduction ratio.
It is configured to receive a throttle drive signal from the intake air amount control means F and perform control to increase the reduction ratio when the drive amount of the electric motor M is small compared to when it is large.

Further, a constant speed running control means G for maintaining the vehicle speed at a set value is provided, and a signal corresponding to the deviation between the actual vehicle speed and the set value is transmitted from the constant speed running control means G to the intake air amount control means. F, and this intake air amount control means F may correct the throttle opening in order to obtain an intake air amount that makes the actual vehicle speed a set value, and performs this constant speed running control. In this case, when the deviation is small and the drive amount of the electric motor M is small, the reduction ratio variable means D increases the reduction ratio.

[0011] The reduction ratio variable means D and the reduction mechanism C
They may be integrally constructed by a mechanical mechanism, and the operating characteristic may be such that when the drive amount of the electric motor M is large, the reduction ratio is smaller than when it is small.

Further, the reduction mechanism C may be a planetary gear mechanism, and the reduction ratio variable means D may be constituted by a clutch that fixes some of its rotating parts.

[0013]

[Function and Effect] The above-mentioned engine intake air amount control device controls the amount of intake air according to driving conditions such as normal accelerator opening, but does not control the intake air amount depending on driving conditions such as normal accelerator opening. In this state, the speed reduction ratio variable means reduces the speed reduction ratio from the electric motor to the throttle valve to increase the throttle valve opening change speed and improve control responsiveness. In a state where the amount of change is small, the reduction ratio is increased to improve the control accuracy of the throttle valve, so that accurate positioning to the target throttle opening can be performed and the desired amount of intake air can be obtained. Moreover, it is possible to achieve both control responsiveness and control accuracy as described above without increasing the required precision of the electric motor or requiring a complex servo system.
Furthermore, by constructing the throttle mechanism using a single electric motor, the throttle mechanism can be made compact, which is also advantageous in terms of cost.

On the other hand, when performing constant-speed running control, the reduction ratio is increased to enable precise control of the opening of the throttle valve, which increases the control accuracy of the intake air amount, that is, the engine output, and allows stable constant-speed running. Control can be executed.

[0015]

DESCRIPTION OF THE PREFERRED EMBODIMENTS Each embodiment of the present invention will be described below with reference to the drawings.

<Embodiment 1> FIG. 2 shows an overall configuration diagram of an engine equipped with an intake air amount control device of this embodiment. An intake port 12 and an exhaust port 13 are opened in the combustion chamber 11 of the engine 10. The openings of both ports 12 and 13 are opened and closed at predetermined timings by an intake valve 15 and an exhaust valve 16, respectively. An air cleaner 18, an intake air amount sensor 19 that measures the amount of intake air, and a throttle valve 20 that controls the amount of intake air are interposed in the intake passage 17 that communicates with the intake port 12 and supplies intake air to the combustion chamber 11 from the upstream side. An injector 22 for injecting and supplying fuel is disposed downstream of the surge tank 21. Also, a bypass passage 24 bypassing the throttle valve 20
The bypass passage 24 is provided with a control valve 25 that adjusts the amount of bypass air.

An electric motor 30 is disposed in conjunction with the throttle valve 20, and a speed reduction mechanism 32 having a variable speed reduction ratio mechanism 31 is interposed between the electric motor 30 and the throttle valve 20. Above throttle valve 2
0 is opened and closed at a predetermined reduction ratio according to the drive of the electric motor 30. Although the detailed structure of the variable reduction ratio mechanism 31 is not shown, the reduction ratio can be changed by operating an actuator.

A control signal is outputted to the electric motor 30 and the variable reduction ratio mechanism 31 from a controller 33 having a CPU or the like therein, and the throttle valve 20 is driven to open and close to a predetermined opening degree with predetermined characteristics, thereby generating an intake air. The amount of air is controlled. A control signal is also output from the controller 33 to the control valve 25 of the bypass passage 24, and the amount of intake air during idling is controlled by the amount of bypass air to control the number of idle rotations.

In order to detect the operating state of the engine, the controller 33 receives an intake air amount signal from an intake air amount sensor 19 for detecting the amount of intake air, as well as a rotation signal from a rotation sensor 35 for detecting the engine speed. signal, the actual throttle opening signal from the throttle sensor 36 that detects the opening of the throttle valve 20, the accelerator opening signal from the accelerator sensor 38 that detects the operation amount of the accelerator pedal 37, and the actual speed of the vehicle being driven. Vehicle speed sensor 39
A vehicle speed signal from a vehicle, a signal from an auto cruise switch 41 operated by the driver to execute constant speed driving control, and the like are input.

The controller 33 basically determines the target throttle opening based on the accelerator opening and the engine speed, compares it with the actual throttle opening, and controls the electric motor 30 according to the deviation between the two. When the auto cruise switch 41 is turned on, the electric motor 30 is driven in the open or close direction depending on the deviation between the set target vehicle speed and the actual vehicle speed. Furthermore, in response to the ON operation of the auto cruise switch 41, a switching signal is output to the variable reduction ratio mechanism 31 to control the reduction ratio to be increased.

Electric motor 3 by the controller 33
0 and the drive control of the variable reduction ratio mechanism 31 will be explained along the flowchart of FIG. After the control starts, it is determined in step S1 whether the auto cruise switch 41 is turned on or not, and when the constant speed cruise control is not performed (NO determination), the process advances to step S2 and the variable reduction ratio mechanism is activated. 31, outputs an off signal to reduce the reduction ratio. As a result, the throttle valve 20 is opened and closed with high responsiveness to the drive of the electric motor 30.

During the normal control, in step S3, the target throttle opening TVo is determined from a map or the like based on the accelerator opening ACC and the engine speed Ne, and
In step S4, the actual throttle opening TV is read from the throttle sensor 36. Then, the deviation between the two is calculated in step S
5 and S7, first, step S
If the actual throttle opening TV is larger than the target throttle opening TVo by a predetermined value α or more as determined in step S6, a reverse rotation signal is output to the electric motor 30 to drive the throttle valve 20 to close. On the other hand, according to the determination in step S7, the actual throttle opening degree TV is set to the target throttle opening degree TV.
o is smaller than a predetermined value α or more, in step S8, a normal rotation signal is output to the electric motor 30 to drive the throttle valve 20 to open.

If the determination in step S1 is YES and the auto cruise switch 41 is turned on to perform constant speed driving control, the process proceeds to step S9 where an on signal is sent to the variable reduction ratio mechanism 31 to increase the reduction ratio. Output. As a result, the throttle valve 20 is opened and closed with increased control accuracy relative to the drive of the electric motor 30. During this constant speed driving control, the actual vehicle speed V and the set target vehicle speed Vo are read in step S10. Then, the deviation between the two is determined in steps S11 and S13. First, if the actual vehicle speed V is larger than the target vehicle speed Vo by a predetermined value β or more as determined in step S11, the difference between the two is determined in steps S11 and S13.
At step 12, a forward rotation signal is output to the electric motor 30 to drive the throttle valve 20 open. On the other hand, if the actual vehicle speed V is smaller than the target vehicle speed Vo by a predetermined value β or more as determined in step S13, a reverse rotation signal is output to the electric motor 30 to close the throttle valve 20 in step S14.

Through the above-described processing, during normal control, the electric motor 30 drives the throttle valve 20 to open and close with a small reduction ratio, obtaining good control responsiveness, resulting in a throttle that responds sensitively to accelerator operation. While the intake air amount is controlled by changing the opening, during constant speed driving control, the throttle valve 20 is opened and closed by the electric motor 30 with a large reduction ratio to obtain control accuracy and precisely control the throttle opening. This adjustment controls the amount of intake air so that the vehicle speed is accurately maintained at the set vehicle speed.

<Embodiment 2> FIGS. 4 and 5 show the reduction mechanism 45 and variable reduction ratio mechanism 46 of the intake air amount control device of this embodiment. In this example, the reduction ratio can be changed steplessly, and the opening/closing operation amount of the throttle opening is large, and the reduction ratio is changed according to the drive amount (drive speed) of the electric motor 30, such as during acceleration. When the drive amount is large, the reduction ratio is reduced and the opening/closing speed of the throttle valve 20 is increased to improve control responsiveness, while when the drive amount of the electric motor 30 is small, such as during constant speed driving control A mechanism for increasing the speed reduction ratio and slowing down the opening/closing speed of the throttle valve 20 to improve control accuracy is provided by a mechanical structure.

FIG. 4 shows the electric motor 30 in a stopped or low speed state, in which a fixed pulley piece 48a of a drive pulley 48 is fixed to the drive shaft 47 of the electric motor 30, and a slide pulley piece 48b is slidable in the axial direction. Spline fitted, both pulley pieces 4
A transmission belt 49 is hung between opposing tapered surfaces of 8a and 48b. A flyweight 50 is disposed on the back surface of the slide pulley piece 48b so as to be movable in the radial direction, and the inclined surface of the distal end of the flyweight 50 is in contact with the inclined surface of the guide member 51. This fly weight 50
When spread outward, the slide pulley piece 48b is moved in the axial direction so as to be pressed toward the fixed pulley piece 48a.

On the other hand, the transmission belt 49 is hung on the opposing tapered surfaces of the driven pulley 52 disposed on the side of the driving pulley 48 on both pulley pieces 52a, 52b.
are spline-fitted to the driven shaft 53 so as to be movable in the axial direction, and the respective pulley pieces 52
a and 52b are biased to clamp the transmission belt 49 by a spring 54 compressed on the back side. A pinion 55 provided at one end of the driven shaft 53
The rotation is then transmitted to the gear 58 of the throttle shaft 20a of the throttle valve 20 via the reduction gear 57 of the intermediate shaft 56.

In the low speed state shown in FIG. 4 above, the flyweight 5
The centrifugal force at 0 is small, the flyweight 50 is located on the center side, the engagement radius of the transmission belt 49 with the drive pulley 48 is small, and the engagement radius with the driven pulley 52 is large, resulting in a large reduction ratio. ing. When the rotational speed of the electric motor 30 increases, the slide pulley piece 48b of the drive pulley 48 moves toward the center as the flyweight 50 moves toward the outer circumference due to centrifugal force, and the transmission belt 49 of the drive pulley 48 moves toward the center. While the engagement radius of the driven pulley 52 becomes larger, the engagement radius of the driven pulley 52 becomes smaller, and the reduction ratio becomes smaller. In this manner, the reduction ratio is large at a low speed relative to the rotational speed of the electric motor 30, and changes to become smaller steplessly as the speed increases.

Furthermore, when controlling the opening of the throttle valve 20 by the electric motor 30, the driving speed of the electric motor 30 gradually increases from a stopped state in response to the output of a drive signal for changing the opening to the target opening. However, when the speed reaches a predetermined speed and becomes close to the target opening, the speed decreases and is controlled to stop when the opening matches the target opening. According to this characteristic, in normal intake air amount control, as the target throttle opening changes greatly, the drive time of the electric motor 30 becomes longer, so the drive speed becomes faster. When the change in throttle opening is small, the driving time of the electric motor 30 is short and the driving speed is slow.

Therefore, in relation to the variable reduction ratio mechanism 46, during acceleration under normal control, even if the reduction ratio in FIG. 4 is large at the initial stage of driving the electric motor 30, as the driving time increases Since the drive speed becomes faster, the reduction ratio becomes smaller, resulting in the state shown in FIG. 5, and the opening degree of the throttle valve 20 changes faster and the control response becomes higher. On the other hand, in constant speed driving control, etc., the driving speed of the electric motor 30 is stopped before the driving speed increases so that the driving time ends and the predetermined opening degree is reached in the initial driving state of the electric motor 30 (FIG. 4). In this state, the reduction ratio is large and the control accuracy is high.

According to the variable reduction ratio mechanism 46 of this example, in addition to achieving both control responsiveness and control accuracy as described above, the reduction ratio at the time of starting the drive of the electric motor 30, which requires a large torque, is large, so that starting is possible. This can be done quickly and allows the use of a small electric motor 30.

<Embodiment 3> FIGS. 6 and 7 show the reduction mechanism 61 and variable reduction ratio mechanism 62 of the intake air amount control device of this embodiment. A planetary gear mechanism is adopted as the reduction mechanism 61, and the reduction ratio is variable. A clutch is used as the mechanism 62.

The drive shaft 63 of the electric motor 30 is connected to the sun gear 6.
4, and a planetary gear 65 is connected to the outside of this sun gear 64.
The outer periphery of the planetary gear 65 meshes with the inner teeth of the ring gear 66. The ring gear 66 and the throttle valve 20 disposed coaxially are connected by a connecting member 67, and the rotation of the ring gear 66 is controlled by the throttle valve 20.
0.

On the other hand, a first clutch 70 capable of locking the rotation of the planetary gear 65 is disposed between the carrier 68 supporting the planetary gear 65 and the planetary gear 65, and a first clutch 70 capable of locking the rotation of the planetary gear 65 is disposed between the carrier 68 and the fixed portion 72. A second clutch 71 capable of fixing the carrier 68 and locking the revolution of the planetary gear 65 is disposed between the second clutch 71 and the second clutch 71 .

The first clutch 70 is connected to the carrier 68.
A clutch housing 73 is provided at one end, and a sliding member 74 fixed to the planetary gear 65 is provided within the clutch housing 73, and the clutch housing 73 and the sliding member 74 are pressed into contact by the biasing force of a spring 75. In this state, the first clutch 70 is configured to be in an engaged state. Further, the carrier 68 passes through the center of the planetary gear 65 so as to be movable in the axial direction toward the second clutch 71, and is provided with a stopper 76 for stopping the movement. A sliding contact member 77 of a second clutch 71 is provided at the other end of the carrier 68, and a clutch housing 78 is disposed on the outer peripheral side of the sliding contact member 77. The clutch housing 78 is installed to be movable in the axial direction, and is pressed by a push solenoid 79 on the back to switch the engagement states of the first and second clutches 70, 71 in conjunction.

Regarding the push solenoid 79,
Similar to the control signal for the variable reduction ratio mechanism 31 of the first embodiment, a control signal from a controller (not shown) is output, and a drive signal is sent to the push solenoid 79 when increasing the reduction ratio as in constant speed driving control. is output, thereby switching the first clutch 70 to the released state and switching the second clutch 71 to the engaged state. Further, during normal control, the drive of the push solenoid 79 is released, and the first clutch 70 is brought into the engaged state, while the second clutch 71 is returned to the released state.

To explain its operation, in the normal control state, when the first clutch 70 is engaged, the planet gear 65 cannot rotate and only revolves, and the sun gear 64, planet gear 65, and ring gear 66 are in a locked state. , the rotation of the sun gear 64 by the electric motor 30 and the rotation of the ring gear 66 are the same, resulting in a drive with a small reduction ratio to obtain control responsiveness. In addition, in the low speed driving control state, the second clutch 7
1, the planetary gear 65 does not revolve, the rotation of the electric motor 30 is transmitted to the sun gear 64, and the planetary gear 65
rotates, and the ring gear 66 is driven at a large reduction ratio due to the reduction of the gear train, resulting in good control accuracy.

[Brief explanation of the drawing]

[Fig. 1] Basic configuration diagram of an engine intake air amount control device of the present invention.

[Fig. 2] Overall configuration diagram of an engine equipped with an intake air amount control device showing a first embodiment.

[Fig. 3] Flowchart diagram for explaining the processing of the controller in the example of Fig. 2.

[Fig. 4] Mechanism diagram showing a speed reduction ratio variable mechanism of the intake air amount control device in the second embodiment.

[Fig. 5] Mechanism diagram showing the change state of the reduction ratio in Fig. 4

[Figure 6
] Mechanism diagram showing the variable reduction ratio mechanism of the intake air amount control device in the third embodiment

[Fig. 7] A perspective view showing the operating principle of Fig. 6.

[Explanation of symbols]

E, 10 Engine B, 20 Throttle valve C, 32, 45, 61 Reduction mechanism M, 30
Electric motor D Variable reduction ratio means G Constant speed traveling control means 31, 46, 62 Variable reduction ratio mechanism 33
Controller 48 Drive pulley 52 Driven pulley 64 Sun gear 65 Planetary gear 66 Ring gears 70, 71 Clutch

Claims (3)

[Claims] 1. An electric motor is installed in an intake passage of an engine to open and close a throttle valve that adjusts the intake air amount, and the operation of the electric motor is controlled according to operating conditions such as accelerator opening. In the engine intake air amount control device which controls the amount of intake air by operating the electric motor to a predetermined opening degree, a reduction mechanism is provided between the electric motor and the throttle valve; An intake air amount control device for an engine, comprising a reduction ratio variable means for increasing the reduction ratio compared to the reduction ratio. 2. The intake air amount control device for an engine according to claim 1, wherein the reduction ratio variable means increases the reduction ratio during constant speed driving control to maintain the vehicle speed at a set value. 3. The reduction mechanism according to claim 1, wherein the reduction mechanism is a planetary gear mechanism, and the reduction ratio variable means is a clutch.
The intake air amount control device for the engine described.