JP2955690B2 - Engine intake air control system - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

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

[0002]

2. Description of the Related Art Conventionally, as an intake air amount control device for an engine, mechanical linkage between an intake system throttle valve and an accelerator mechanism is eliminated, and this throttle valve is opened and closed by driving an electric motor, and its opening and closing characteristics are controlled. A technique for increasing the degree of freedom is known as disclosed in, for example, JP-A-63-314328. When an electronically controlled throttle valve that adjusts the intake air amount of the engine by driving the throttle valve with an electric motor as described above is used, the amount of intake air, that is, the amount of intake air, This makes it possible to perform traction control or the like for adjusting the engine output.

On the other hand, as in the case of constant-speed running control in which the engine output is adjusted in accordance with the deviation between the actual vehicle speed and the set value so as to maintain the vehicle speed at the set value, the intake air of the engine is independent of the accelerator operation by the driver. Techniques for controlling the amount are also commonly employed. The actuator for the constant-speed running control is usually performed by adjusting the accelerator opening.

[0004]

When the throttle valve is opened and closed by an electric motor as described above, the target throttle opening is changed when the throttle opening is changed based on various controls. However, there is a problem that it is difficult to achieve a balance between the responsiveness until the position reaches the target position and the positioning accuracy for matching the target opening.

That is, when an electric motor such as a step motor is connected to a throttle valve and a mechanism for opening and closing the throttle valve is installed, when the throttle valve needs to be opened and closed rapidly such as during rapid acceleration or sudden deceleration. For example, it is preferable to increase the opening / closing speed by setting a large throttle angle for opening / closing by one-step driving of the motor, and to improve the responsiveness of the opening / closing operation to the target throttle opening. However, when the opening / closing speed is increased and the amount of movement in one step is increased with an emphasis on responsiveness, for example, when performing constant speed traveling control, the set vehicle speed and the actual vehicle speed become close to each other and the target throttle opening degree is increased. When the deviation between the actual throttle opening and 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 is low. Conversely, if the amount of movement in one step is reduced so as to increase the control accuracy, the change speed of the throttle opening is low, and good responsiveness cannot be obtained.

On the other hand, providing an electric motor and a servo system capable of obtaining both the characteristics of control response and control accuracy as described above requires a high accuracy required of the electric motor and a complicated and expensive servo system. And it becomes difficult to adopt it in general engines. In addition, an electric motor that opens and closes the throttle valve with characteristics that emphasize responsiveness in response to accelerator operation, and an electric motor that opens and closes the throttle valve with characteristics that emphasize control accuracy, such as for constant-speed cruise control, are separately provided. The installation also hinders the downsizing of the throttle drive mechanism, and it is preferable to drive with a single electric motor.

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

[0008]

In order to achieve the above object, an intake air amount control device according to the present invention comprises a throttle valve for adjusting an intake amount in an intake passage A of an engine E, as shown in FIG. B, and the throttle valve B
Is connected to an electric motor M via a speed reduction mechanism C, and the opening and closing operation of the throttle valve B is performed by driving the electric motor M. The electric motor M has an intake air amount control means F.
Control signal from the intake air amount control means F
Outputs a control signal for opening and closing the throttle valve B so as to attain an intake air amount according to an operation state such as an accelerator opening degree, that is, a target throttle opening degree, and controls the intake air amount.

Between the electric motor M and the throttle valve B, a speed reduction mechanism C and a speed reduction ratio variable means D for changing the speed reduction ratio are provided.
Upon receiving a throttle drive signal from the intake air amount control means F, control is performed to increase the speed reduction ratio when the drive amount of the electric motor M is small as compared to when the drive amount is large.

Further, a constant speed traveling control means G for maintaining the vehicle speed at a set value is provided, and a signal corresponding to a deviation between the actual vehicle speed and the set value is output from the constant speed traveling control means G. F, the intake air amount control means F may control the throttle opening to correct the intake air amount so that the actual vehicle speed becomes a set value. When the deviation is small and the driving amount of the electric motor M is small, the speed reduction ratio varying means D increases the speed reduction ratio.

The speed reduction ratio varying means D and the speed reduction mechanism C
May be integrally configured by a mechanical mechanism, and may be configured to have an operating characteristic in which the reduction ratio is smaller when the driving amount of the electric motor M is large than when it is small.

Further, the speed reduction mechanism C may be a planetary gear mechanism, and the reduction ratio variable means D may be constituted by a clutch for fixing a part of the rotating parts.

[0013]

In the above-described engine intake air amount control device, the amount of change in the throttle opening degree is large as in the case of acceleration / deceleration by controlling the intake air amount according to the operating state such as the normal accelerator opening degree. In this state, the speed reduction ratio from the electric motor to the throttle valve is reduced by the speed reduction ratio varying means to increase the speed of change in the opening degree of the throttle valve, thereby increasing the control responsiveness. When the amount of change is small, the control speed of the throttle valve is increased by increasing the speed reduction ratio, accurate positioning to the target throttle opening can be performed, and a desired intake air amount can be obtained. Moreover, it is possible to achieve both the above-described control responsiveness and control accuracy without improving the required accuracy of the electric motor and without requiring a complicated servo system.
Further, by using a single electric motor, the throttle mechanism can be made more compact, which is advantageous in terms of cost.

On the other hand, when performing the constant-speed running control, the speed reduction ratio is increased to enable precise control of the opening of the throttle valve. Control can be performed.

[0015]

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

An electric motor 30 is provided in association with the throttle valve 20, and a reduction mechanism 32 having a variable reduction ratio mechanism 31 is interposed between the electric motor 30 and the throttle valve 20. The throttle valve 20 is an electric motor
Opening / closing operation is performed at a predetermined reduction ratio according to the drive of 30. Although not shown in detail, the reduction ratio variable mechanism 31 is configured such that its reduction ratio can be switched by operation of an actuator.

The electric motor 30 and the variable reduction ratio mechanism 31
In response, a control signal is output from a controller 33 having a CPU and the like, and the throttle valve 20 is driven to open and close to a predetermined opening with a predetermined characteristic to control the intake air amount. Further, a control signal is also output from the controller 33 to the control valve 25 of the bypass passage 24, and the idling speed is controlled by controlling the intake air amount at idling by the bypass air amount.

The controller 33 includes an intake air amount signal from an intake air amount sensor 19 for detecting an intake air amount for detecting an operating state of the engine, and a rotation signal from a rotation sensor 35 for detecting an engine speed. Signal, an actual throttle opening signal from a throttle sensor 36 that detects the opening of the throttle valve 20, an accelerator opening signal from an accelerator sensor 38 that detects the amount of operation of an accelerator pedal 37, and a vehicle speed that is actually running. Vehicle speed signal from the vehicle speed sensor 39,
A signal or the like of the auto cruise switch 41 operated by the driver to execute the constant speed traveling control is input.

The controller 33 basically determines the target throttle opening based on the accelerator opening and the engine speed, compares the target throttle opening with the actual throttle opening, and responds to the deviation between the two. Is driven in the opening or closing direction, and when the auto cruise switch 41 is turned on, the electric motor 30 is moved in the opening or closing direction according to the deviation between the set target vehicle speed and the actual vehicle speed. The automatic cruise switch 41
A switching signal is output to the reduction gear ratio variable mechanism 31 in response to the ON operation of the control signal to control the reduction gear ratio to be increased.

The drive control of the electric motor 30 and the variable reduction ratio mechanism 31 by the controller 33 will be described with reference to the flowchart of FIG. After the control is started, it is determined whether or not the auto cruise switch 41 is turned on in step S1. If the vehicle is in the normal control in which the constant speed traveling control is not performed (NO determination), the process proceeds to step S2 and the speed reduction ratio variable mechanism is performed. An off signal for reducing the reduction ratio is output to 31. This allows
The throttle valve 20 is opened and closed in a state of high response to the drive of the electric motor 30.

In the normal control, the target throttle opening TVo is determined from a map or the like based on the accelerator opening ACC and the engine speed Ne in step S3, and the actual throttle opening TV is read from the throttle sensor 36 in step S4. The difference between the two is determined in steps S5 and S7. First, if the actual throttle opening TV is larger than the target throttle opening TVo by a predetermined value α or more in step S5, step S6 is performed.
To output the reverse rotation signal to the electric motor 30 and use the throttle valve
Drive 20 closed. On the other hand, if the actual throttle opening TV is smaller than the target throttle opening TVo by a predetermined value α or more in the determination in step S7, the electric motor 30 is switched in step S8.
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 traveling control, the process proceeds to step S9, where the ON signal for increasing the reduction ratio is transmitted to the variable reduction ratio mechanism 31. Is output. This allows the throttle valve 20 to be driven with respect to the drive of the electric motor 30.
Opening / closing operation is performed in a state where the control accuracy of is increased. At the time of the constant speed traveling control, the target vehicle speed Vo set as the actual vehicle speed V in step S10 is read. The difference between the two is determined in steps S11 and S13. First, the actual vehicle speed V is determined by the determination in step S11 from the target vehicle speed Vo by a predetermined value β.
If it is larger than the above, a forward rotation signal is output to the electric motor 30 to open the throttle valve 20 in step S12. On the other hand, according to the determination in step S13, the actual vehicle speed V becomes the target vehicle speed Vo.
If the value is smaller than the predetermined value β or more, a reverse rotation signal is output to the electric motor 30 to drive the throttle valve 20 to close in step S14.

According to the above-described processing, the throttle valve 20 is opened and closed by the electric motor 30 in a state where the speed reduction ratio is small during normal control to obtain a good control response, and the throttle responds sensitively to the accelerator operation. While controlling the intake air amount by changing the opening, at the time of constant speed traveling control, the electric motor 30 opens and closes the throttle valve 20 with the reduction ratio increased to obtain control accuracy,
The intake air amount is controlled so that the vehicle speed is accurately maintained at the set vehicle speed by finely adjusting the throttle opening.

<Embodiment 2> FIGS. 4 and 5 show a speed reduction mechanism 45 and a reduction ratio variable mechanism 46 of the intake air amount control device of this embodiment. In this example, the reduction ratio can be changed in a stepless manner, and the opening / closing operation amount of the throttle opening is large, and the reduction ratio is changed in accordance with the driving amount (driving speed) of the electric motor 30. When the driving amount is large, the reduction ratio is reduced to increase the opening / closing speed of the throttle valve 20 to increase the control responsiveness. On the other hand, when the driving amount of the electric motor 30 is small as in the case of constant speed traveling control, A mechanism for increasing the reduction ratio and increasing the opening / closing speed of the throttle valve 20 to increase the control accuracy is obtained by a mechanical structure.

FIG. 4 shows a state in which the electric motor 30 is stopped or in a low speed state. A fixed pulley piece 48a of a driving pulley 48 is fixed to a drive shaft 47 of the electric motor 30.
A slide pulley piece 48b is spline-fitted so as to be slidable in the axial direction, and a transmission belt 49 is hung on opposing tapered surfaces of both pulley pieces 48a, 48b. A fly weight 50 is disposed on the rear surface of the slide pulley piece 48b so as to be movable in the radial direction, and the tip inclined surface of the fly weight 50 is in contact with the inclined surface of the guide member 51. When the fly weight 50 spreads outward, the fly weight 50 moves in the axial direction so as to press the slide pulley piece 48b toward the fixed pulley piece 48a.

On the other hand, the transmission belt 49 is provided on the opposing tapered surface of the driven pulley 52 disposed on the side of the driving pulley 48.
Are spline-fitted to the driven shaft 53 so as to be movable in the axial direction. It is energized as follows. The gear of the throttle shaft 20a of the throttle valve 20 is transmitted from a pinion 55 provided at one end of the driven shaft 53 via a reduction gear 57 of an intermediate shaft 56.
The rotation is transmitted to 58.

In the low-speed state shown in FIG.
Centrifugal force is small, the fly weight 50 is located on the center side, the engagement radius of the transmission belt 49 with the drive pulley 48 is small,
The engagement radius of the driven pulley 52 is large, and the reduction ratio is large. When the rotation speed of the electric motor 30 increases, the slide pulley piece 48b of the drive pulley 48 moves to the center side in accordance with the fly weight 50 moving to the outer peripheral side due to centrifugal force, and the transmission belt 49 of the drive pulley 48 The engagement radius of the driven pulley 52 is small, and the reduction ratio is small. As described above, the speed reduction ratio is large at a low speed with respect to the rotation speed of the electric motor 30, and the speed reduction ratio changes steplessly as the speed increases.

When the opening control of the throttle valve 20 is performed by the electric motor 30, the driving speed of the electric motor 30 gradually increases from the stop state in response to the output of the driving signal for changing to the target opening. Then, when the speed reaches a predetermined speed and approaches the target opening, the speed is reduced, and control is performed so as to stop when the speed matches the target opening. According to this characteristic, in the normal intake air amount control, the drive speed is increased because the drive time of the electric motor 30 is long as the target throttle opening greatly changes. When the change in the throttle opening is small, the driving time of the electric motor 30 is short, and the driving speed is low.

Therefore, in relation to the variable reduction ratio mechanism 46, the electric motor 30
In the initial stage of the drive, even if the reduction ratio in FIG. 4 is large, the drive speed increases as the drive time increases, so that the reduction ratio becomes small and the state in FIG. Control response is high. On the other hand, in the constant-speed running control or the like, the electric motor 30 is stopped before the driving speed is increased so that the driving time ends and reaches a predetermined opening 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 the present embodiment, in addition to achieving both the above-described control responsiveness and control accuracy, since the reduction ratio at the start of driving of the electric motor 30 requiring a large torque is large, the start-up is possible. It can be performed quickly and the small electric motor 30 can be used.

<Embodiment 3> FIGS. 6 and 7 show a reduction mechanism 61 and a 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.
A clutch is used as the reduction ratio variable mechanism 62.

The drive shaft 63 of the electric motor 30 is connected to a sun gear 64, and a planetary gear 65 meshes with the outside of the sun gear 64, and the outer periphery of the planetary gear 65 meshes with the internal teeth of the ring gear 66. Then, the throttle valve 20 disposed coaxially with the ring gear 66 is connected by a connecting member 67, and the rotation of the ring gear 66 is transmitted to the throttle valve 20.

On the other hand, a carrier for supporting the planetary gear 65
A first clutch 70 capable of locking the rotation of the planetary gear 65 is disposed between the planetary gear 68 and the planetary gear 65.
The carrier 68 is fixed between the
A second clutch 71 capable of locking 65 revolutions is provided.

In the first clutch 70, a clutch housing 73 is provided at one end of the carrier 68, and a sliding contact member 74 fixed to the planet gear 65 is provided in the clutch housing 73. The first clutch 70 is configured to be engaged when the spring 75 is pressed against the contact member 74 by the urging force of the spring 75. The carrier 68 penetrates through the center of the planet gear 65 toward the second clutch 71 so as to be movable in the axial direction, and a stopper 76 for stopping the movement is formed. At the other end of the carrier 68, a sliding contact member 77 of the second clutch 71 is provided.
A clutch housing 78 is arranged on the outer peripheral side of the clutch housing 78. The clutch housing 78 is installed so as to be movable in the axial direction, and is pressed by a push solenoid 79 at the back to switch the engagement state of the first and second clutches 70 and 71 in conjunction with each other.

A control signal from a controller (not shown) is output to the push solenoid 79 in the same manner as the control signal for the speed reduction ratio variable mechanism 31 of the first embodiment, and the speed is reduced as in the case of constant speed traveling control. When increasing the ratio, a drive signal is output to the push solenoid 79 to put the first clutch 70 into the disengaged state and switch the second clutch 71 into the engaged state. Also, during normal control, the drive of the push solenoid 79 is released to bring the first clutch 70 into the engaged state, and return the second clutch 71 to the released state.

To explain the operation, in the normal control state, the planetary gear 65 cannot rotate by the engagement of the first clutch 70, and only revolves.
The ring gear 66 is locked, the rotation of the sun gear 64 by the electric motor 30 and the rotation of the ring gear 66 become the same,
Drive with a small reduction ratio provides control responsiveness. Also,
In the low-speed traveling control state, the planetary gear 65 does not revolve due to the engagement operation of the second clutch 71, the rotation of the electric motor 30 is transmitted to the sun gear 64, the planetary gear 65 rotates, and the ring gear 66 rotates with the reduction of the gear train. It is driven in a state where the reduction ratio is large, and good control accuracy is obtained.

[Brief description of the drawings]

FIG. 1 is a basic configuration diagram of an intake air amount control device for an engine according to the present invention.

FIG. 2 is an overall configuration diagram of an engine including an intake air amount control device according to a first embodiment;

FIG. 3 is a flowchart for explaining processing of a controller in the example of FIG. 2;

FIG. 4 is a mechanism diagram showing a speed-reduction-speed variable mechanism of an intake air amount control device according to a second embodiment.

FIG. 5 is a view of the same mechanism showing a change state of the reduction ratio of FIG. 4;

FIG. 6 is a mechanism diagram showing a variable reduction ratio mechanism of an intake air amount control device according to a third embodiment.

FIG. 7 is a perspective view showing the operation 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 Reduction ratio variable means G Constant speed traveling control means 31,46,62 Reduction ratio variable mechanism 33 Controller 48 Drive pulley 52 Follower Pulley 64 Sun gear 65 Planetary gear 66 Ring gear 70,71 Clutch

Continuation of the front page (72) Inventor Eternal Fujita 3-1, Shinchi, Fuchu-cho, Aki-gun, Hiroshima Prefecture Inside Mazda Corporation (56) References JP-A-60-1347 (JP, A) JP-A-2-67435 ( JP, A) JP-A-4-203327 (JP, A) JP-A-62-129531 (JP, A) U.S. Pat. No. 4,526,060 (US, A) (58) Fields investigated (Int. Cl. ⁶ , DB name) F02D 9/00-11/10

Claims (3)

(57) [Claims] An electric motor is provided in an intake passage of an engine to open and close a throttle valve for adjusting an intake air amount, and controls the operation of the electric motor in accordance with an operation state such as an accelerator opening to control a throttle valve. Is controlled to a predetermined opening to control the intake air amount. In the intake air amount control device for an engine, when the drive amount of the electric motor is small, the speed reduction mechanism between the electric motor and the throttle valve is large. An intake air amount control device for an engine, comprising: a speed reduction ratio variable means for increasing a speed reduction ratio as compared with the above. 2. An intake air amount control device for an engine according to claim 1, wherein said reduction ratio varying means increases a reduction ratio during a constant speed traveling control for maintaining a vehicle speed at a set value. 3. The intake air amount control device for an engine according to claim 1, wherein the speed reduction mechanism is a planetary gear mechanism, and the reduction ratio variable means is a clutch.