JP2002004894A - Control method for exhaust pipe valve device - Google Patents

Abstract

PROBLEM TO BE SOLVED: To prevent influence of friction or sticking between a valve housing, and a valve element and a rotary shaft, and to smoothly control an exhaust pipe valve device, at the valve device actuation. SOLUTION: In this control method for the exhaust pipe valve device 11, an actuator 21 has a reduction gear-equipped electric motor 22 turning the valve element 5; a position sensor 23 for detecting a turn position of the valve element 5; and a controller 24 for setting a turn target position of the valve element 5, and driving the electric motor 22b by PWM control on the basis of a difference between a position signal c from the position sensor 23 and a target position signal d of the turn target position, such that the turn position of the valve element 5 becomes the turn target position. When the turn position of the valve element 5 turns into the turn target position, the controller 24 applies minute oscillation of a switching frequency in the PWM control to a rotary shaft 6 and the valve element 5 via the electric motor 22b, on the basis of the minute difference between the signal c of the turn position of the valve element 5 and the signal d of the turn target position.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a control method of a motor-driven butterfly valve type exhaust pipe valve device, and more particularly to an improved control method.

[0002]

2. Description of the Related Art Conventionally, as an exhaust pipe valve device 1 to which this type of control method is applied, for example, a front view of a part of the device shown in FIG. 12 and a part of the device shown in FIG. Some are shown in the side view. 12 and 13, the exhaust pipe valve device 1 is provided in an exhaust pipe of an engine, and forms a part of an exhaust passage 2 of a valve 3.
And a disc-shaped valve element 5 disposed inside the valve housing 4 for opening and closing the exhaust passage 2
A valve 3 comprising a rotary shaft 6 to which the valve body 5 is fixed and which is rotatably supported by the valve housing 4; and a negative pressure actuated actuator 7 for rotating the rotary shaft 6. It is composed of

The negative pressure chamber 7 of the actuator 7
The actuator 7 is actuated by a negative pressure supplied from a negative pressure source (not shown) via a supply / discharge pipe 7 b to the valve a. The exhaust passage 2 is opened and closed. That is, the lever 8 fixed to one shaft end 6a of the rotary shaft 6 corresponds to the axial position of the drive shaft 7c of the actuator 7,
Rotational driving force is transmitted from the actuator 7 via the drive shaft 7c to rotate the rotation shaft 6 to open and close the exhaust passage 2 with the valve body 5, and to operate the actuator 7 in two stages (half-step). (Closed and fully closed) for warm air. FIG. 13 shows the valve open state. And
The movement of the lever 8 when the valve body 5 is opened and closed is performed by engaging the engaging surfaces 8a and 8b on the heads of two stopper bolts 9 and 10 provided on a bracket 7i shown in FIG. Each is regulated by contact.

A first return spring 7f is disposed between the power piston 7d and a shell (housing for the actuator) 7e as a return spring of the power piston 7d of the actuator 7, and the power piston 7d is connected to the power piston 7d by a power. A second return spring 7g is arranged between the piston 7d and a retainer 7h movably attached to the piston 7d.

Therefore, the negative pressure chamber 7 of the actuator 7
When a low negative pressure is supplied to a, the power piston 7d
Only the first return spring 7f bends and strokes until the retainer 7h comes into contact with the shell 7e to bring the valve element 5 into the first-stage semi-closed state. Next, when a high negative pressure (a negative pressure closer to vacuum than the low pressure) is supplied to the negative pressure chamber 7a of the actuator 7, the power piston 7d
By bending the first and second return springs 7f and 7g together, the stroke is made until the engagement surface 8b of the lever 8 of the rotary shaft 6 comes into contact with the stocker bolt 10, and the valve body 5 is moved to the second stage. Make it fully closed.

As described above, the opening degree of the valve element 5 is controlled by changing the negative pressure supplied to the actuator 7.
The warm air includes warm air during idling and warm air during traveling. In the warm air during idling, the halve is fully closed, and in the warm air during traveling, valve half-close control is performed. In the warming-up during traveling, the warm-up operation is performed during low-speed traveling with a small accelerator opening, and the warming-up operation is not performed during high-speed traveling with a large accelerator opening.

On the other hand, as another conventional exhaust pipe valve device, there is one in which the actuator 7 is an electric motor with a reduction gear. Recently, a motor-driven butterfly valve type exhaust pipe valve device provided by the present inventors has been proposed. is there. (Japanese Patent Application 2
No. 000-102911) This exhaust pipe valve device is provided in an exhaust pipe of an engine, and is fixed to a valve housing forming a part of an exhaust passage thereof and a rotating shaft rotatably supported in the valve housing. An exhaust pipe valve device comprising: a valve element to be rotated; and an actuator for rotating the rotation shaft, and the actuator operates to rotate the valve element to open and close the exhaust passage.

The actuator comprises an electric motor with a speed reducer for rotating the valve body via the rotary shaft, a position sensor for detecting a rotation position of the valve body, and a controller. The controller sets, for example, a rotation target position of the valve body based on signals from an accelerator switch and an accelerator opening sensor, and sets a position signal from the position sensor and a target of the rotation target position. The electric motor is driven and controlled such that the rotation position of the valve body becomes the rotation target position based on a difference from a position signal.

[0009]

However, the conventional exhaust pipe valve apparatus 1 and the motor-driven butterfly valve type exhaust pipe valve apparatus have the following problems. 1) Soot in the exhaust gas adheres to the valve body and the rotating shaft portion of the halve, or rust is generated, and the valve body and the rotating shaft adhere to the valve housing. The movement of the valve body and the rotating shaft is deteriorated. 2) For this reason, fluctuations in engine exhaust gas pressure, fluctuations in the frictional resistance of the rotary shaft of the butterfly valve, and the like cause variations in the opening and closing angles of the valve, making it impossible to accurately control the position of the valve device.

[0010] The present invention has been made in view of such a point,
The object is to solve the above-mentioned problems, and to prevent the influence of the above-mentioned sticking or friction between the valve body and the rotating shaft and the valve housing at the time of operation, to make the movement smooth and accurate. It is to propose a control method of an exhaust pipe valve device capable of performing position control.

Another object of the present invention is to provide an exhaust pipe valve capable of precisely controlling the position of the valve body based on an engine opening temperature, an engine cooling water temperature, an exhaust gas pressure, an engine speed, and the like in operation. It is to propose a control method of the device.

[0012]

According to an aspect of the present invention, there is provided a valve housing provided in an exhaust pipe of an engine and forming a part of an exhaust passage, and a valve housing provided in the valve housing. An exhaust that has a valve body that is fixed to a rotating shaft that is movably supported, and an actuator that rotates the rotation shaft, and that operates the actuator to rotate the valve body to open and close the exhaust passage. The control of the pipe valve device is as follows.

The actuator is provided with an electric motor with a speed reducer for rotating the valve body via the rotation shaft, a position sensor for detecting a rotation position of the valve body, and a rotation target position of the valve body. PWM (pulse width) so that the rotation position of the valve body becomes the rotation target position based on the difference between the position signal from the position sensor and the target position signal of the rotation target position. And a controller for driving the electric motor by the modulation) control. When the rotation position of the valve body reaches the rotation target position, the controller controls a signal of the rotation position of the valve body and the controller. This is a control method for applying a vibration of a switching frequency in the PWM control to the rotating shaft and the valve body via the electric motor based on a small deviation from a signal of a moving target position.

The controller further includes a valve position target value setting circuit having a control pulse generation circuit, and a motor drive control circuit including an A / D converter, an adder, and an amplifier. A control pulse signal that is set in accordance with the magnitude of the target closing degree of the valve body based on output signals from an engine speed detection sensor, an accelerator opening sensor, a cooling water temperature sensor, and an exhaust gas pressure sensor. Output, the A / D converter converts the position signal of the valve element input from the position sensor into a digital pulse signal, and the adder controls a control pulse signal from the control pulse generation circuit; The difference from the converted pulse signal from the A / D converter is taken, and the difference is defined as the energizing time, and the switching frequency is the switching frequency of the control pulse signal. And outputs the same pulse signal, by the amplifier, based on the pulse signal from the adder, a control method for outputting power to drive the electric motor.

The switching frequency of the control pulse signal is 100 to 150 Hz (period is 10 to 6.7 ms).
Is a control method.

Since the present invention is configured as described above, when the rotation position of the valve body reaches the rotation target position, the controller is configured to perform a disturbance, for example, external vibration, exhaust gas pressure or gas temperature. A ripple current of a switching frequency in the PWM control is output based on a small deviation between the rotation position of the valve body and the rotation target position, which is generated due to fluctuation of the rotation of the valve body. The frequency, desirably 100 to 100, is applied to the shaft and the valve body.
A dither effect is generated by applying a small vibration of 150 Hz (vibration due to minute reciprocating rotation). As a result, sticking between the valve body and the rotating shaft and the valve housing due to soot and rust in exhaust gas is prevented, and friction is reduced.

Further, accurate and precise control is enabled based on the engine cooling water temperature, the exhaust gas pressure, the engine speed and the like in addition to the accelerator opening.

[0018]

DESCRIPTION OF THE PREFERRED EMBODIMENTS Preferred embodiments of the present invention will be described below in detail with reference to the drawings. 1 to 11
FIG. 1 shows an embodiment of a control method of an exhaust pipe valve device according to the present invention. First, a structure of an exhaust pipe valve device which is an object of the control method will be described with reference to FIGS.
FIG. 1 is a perspective view showing the entire exhaust pipe valve device, FIG. 2 is a longitudinal sectional view showing a part of the exhaust pipe valve device, and FIG.
2 is a right side view of FIG. 2, FIG. 4 is a cross-sectional view taken along line IV-IV of FIG. 2, and FIG. 5 is a cross-sectional view taken along line VV of FIG. Are assigned the same reference numerals,
The description is omitted.

1 to 5, the exhaust pipe valve device 11 mainly includes the butterfly type halve 3, an actuator 21, and a connecting mechanism 31. The valve 3 includes a valve housing 4 that forms a part of an exhaust gas passage 2 of a vehicle engine, a disc-shaped valve body 5 that opens and closes a substantially circular internal passage 4 a of the valve housing 4, The body 5 is fixed and comprises a rotary shaft 6 rotatably supported by the valve housing 4 via a seal member (eg, a labyrinth seal) 4b.

The actuator 21 includes the rotary shaft 6
An electric motor 22 with a speed reducer for rotating the motor, a position sensor 23 for detecting the rotational position of the rotary shaft 6, and an electronic circuit for driving and controlling the electric motor 22 with the speed reducer. And a controller 24 to be arranged. The coupling mechanism 31 includes a finned coupling 32 for directly coupling between the rotary shaft 6 of the halve 3 and the speed reduction output shaft 22a of the electric motor 22 with the speed reducer of the actuator 21; It becomes the housing 33.

The controller 24 of the actuator 21 includes a position signal indicating the degree of closing of the valve 3 by the valve body 5 from the position sensor 23 via the deceleration output shaft 22a, and a controller described later. 24, the electric motor 22 with a speed reducer is driven by a target value signal of a valve position set inside the control valve 24 and a control pulse signal generated therein. Control to position.

The electric motor 22b of the electric motor 22 with a reduction gear is a DC motor, and the mechanism of the reduction gear 22c is a worm gear 22d or a hypoid gear. In the case where the mechanism of the speed reducer 22c is a hypoid gear, there is an advantage that rotation due to the rotational force from the valve 3 side by the valve body 5 due to fluctuation of exhaust gas pressure or the like can be prevented due to its irreversibility.

The valve housing 4 of the valve 3 includes:
The connecting mechanism 31 is attached via a plurality of bolts 12, and the actuator 21 is attached to the housing 33 of the connecting mechanism 31 by fastening a plurality of bolts 34. Here, the housing 33 of the connection mechanism 31 is made of an aluminum-based material to dissipate heat from the bulb 3.

One end of the deceleration output shaft 22a of the speed reducer 22c of the actuator 21 is connected to the rotary shaft 6 of the valve 3 by a finned coupling 32 made of an aluminum-based material having good heat dissipation. At the other end of the deceleration output shaft 22a, the position sensor 23 for detecting the rotational position of the rotary shaft 6 of the valve 3 is provided. Note that a gear connection may be used instead of the finned coupling 32.

The rotary shaft 6 of the valve 3 has a shaft portion 6b on the finned coupling 23 side, and a lever 18 fixed to the shaft portion 6b and the connecting mechanism 31.
Between the housing 33 and the torsion spring 35
The rotary shaft 6 is always urged in the inoperative position direction, and is opened when the valve 3 is not operated.

Further, a bent portion 33a is formed on the side of the housing 33, and the lever 18 fixed to the rotary shaft 6 is attached to the torsion spring 35 when the valve 3 is in the non-operating (fully open) position. The force makes contact with the bent portion 33a. At the same time, when the valve 3 is operated (fully closed), the lever 18 comes into contact with the head 36a of a stopper bolt 36 provided on the housing 33.

Here, since the electric motor 22b of the actuator 21 is susceptible to high temperatures, it is necessary to keep the electric motor 22b as far away from the exhaust passage 2 as possible and to prevent high heat from the exhaust passage 2. For this reason, the finned coupling 32 is made of an aluminum-based material having good heat dissipation, and the electric motor 22b is moved as far as possible from the exhaust passage 2 by the housing 33 that houses the coupling 32 and the connection gear. To Further, a heat shield (insulator) 25 is provided between the valve housing 4 and the electric motor 22b to block high heat from the exhaust passage 2. In addition, 37 is a drain pipe.

Next, the control of the exhaust pipe valve device by the controller will be described with reference to FIGS. FIG. 6 shows the exhaust pipe valve device 11,
The electric motor 22 with the reduction gear of the actuator 21
FIG. 7 is a control block diagram showing a control system of the controller 24 that drives and controls the position of the valve 3. FIG. 7 is a diagram showing the relationship between the position (angle) of the valve 3 and the output voltage (analog signal) of the position sensor 23. Receives the output signal of the position sensor 23, and in accordance with a valve position target value (valve target position) output from a valve position target value setting circuit,
FIG. 4 is a diagram illustrating conversion characteristics of an A / D converter that converts and outputs a digital signal. The digital signal is a conversion pulse signal that outputs a conduction time with a pulse width. FIG.
10 is a block diagram showing a digital servo control system based on PWM (pulse width modulation) control. FIG. 10 is a basic block diagram of a motor drive control circuit of the controller 24, a control system of the electric motor 22b, and a control system of the position sensor 23.
FIG. 11 is a diagram showing a pulse signal at the time of operation in each section in the controller 24. FIG. 11 is a view showing minute vibrations at the valve target position of the electric motor 22b when the switching cycle in the PWM control is changed. It is a figure showing a change.

In FIG. 6, the controller 24 comprises:
A valve position target value setting circuit 40 having a control pulse generation circuit 41; an A / D converter 46; an adder 47;
8 and a motor drive control circuit 45 comprising:

The valve position target value setting circuit 40 includes:
Engine speed detection sensor 51, accelerator opening sensor 5
2, cooling water temperature sensor 53 and exhaust gas pressure sensor 5
4, the control pulse generation circuit 41 determines the target closing degree (target position) of the valve 3, that is, the target closing degree of the valve body 5 based on these signals. The control pulse signal a set accordingly is output to the adder 47 of the motor drive control circuit 45.

On the basis of the control pulse signal a from the control pulse generation circuit 41, the motor drive control circuit 45
The electric motor 22 is controlled by WM (pulse width modulation) control.
b is driven and controlled. Here, the control pulse signal a
The power supply time (pulse width) is adjusted by adjusting the duty ratio while keeping the switching cycle constant. And
When the electric motor 22b is driven to increase the valve closing degree, the duty ratio is increased and the energizing time is increased. Conversely, when the valve closing degree is to be small, the duty ratio is made small and the energization time is made short. The control pulse signal a is output from the controller 24 even when the valve 3 is at the target position even when it is not operating. When the valve is not operated, the control pulse signal a has a pulse width corresponding to the output voltage of the position sensor 23 when the valve is not operated (fully opened). When the operation is maintained, the output voltage of the position sensor 23 at the target position is output. Becomes a control pulse signal a having a pulse width corresponding to. The motor drive control circuit 45 includes:
Signals from the warm air switch 55, the exhaust brake switch 56, and the clutch switch 57 are input.

The A / D converter 46 of the motor drive control circuit 45 outputs a position signal from the position sensor 23 as a voltage proportional to the position (angle) of the valve element 5 as shown in FIG. (Analog position signal) c is input,
The analog position signal c of the valve element 5 is converted into a digital signal, and a converted pulse signal d is output to the adder 47.

In the A / D converter 46, as shown in FIG. 8, based on the set conversion line A, the energization time (output voltage) c proportional to the analog position signal (output voltage) c from the position sensor 23 is determined. (Pulse width), and a conversion pulse signal d having the same switching frequency cycle as the control pulse signal a is generated in the energization time. That is, the A / D converter 46 has the same duty ratio as the control pulse signal a when the valve position reaches the target position based on the conversion line A, and is proportional to the analog position signal c. And A /
The D-converted converted pulse signal d is output.

The adder 47 is provided with a control pulse signal a input from the control pulse generation circuit 41 and the A / D
The conversion pulse signal d from the converter 46 is subtracted to generate an output pulse signal e having the same energization time as the difference and having the same switching frequency as the switching frequency of the control pulse signal a. Output to When the valve 3 starts operating from the non-operating state, since the valve 3 is in the fully open position, the energizing time (pulse width) of the conversion pulse signal d is determined from the energizing time (pulse width) of the control pulse signal a. ) Is considerably smaller, so that an output pulse signal e having a relatively large energization time (pulse width) is generated, but as the valve 3 rotates and approaches the target position,
Since the passing time (pulse width) of the conversion pulse d increases, the energizing time (pulse width) of the output pulse signal e gradually decreases. That is, the adder 47 controls the output pulse signal e such that the pulse width decreases with respect to the control pulse signal a as the position approaches the target position.
Is output. (The output pulse signal e is output in which the switching cycle is the same and the duty ratio decreases as the position approaches the target position.)

The amplifier 48 amplifies power (for example, 5 volts at the maximum) based on the output pulse signal e input from the adder 47, and outputs it to the electric motor 22b as a motor drive pulse current f. The amplifier 28 generally includes a digital controller 48a, a power driver 48b, and a current feedback circuit 48c, each of which is shown in a portion surrounded by a dashed line in the block diagram of the digital servo control system shown in FIG. Have been. The electric motor 22b is driven by the motor drive pulse current f output from the amplifier 48, and the valve 3, that is, the valve body 5, is rotated. The rotation position of the valve 3 is detected by the position sensor 23, and the sequence of the A / D converter 46, the adder 47, the amplifier 48, and the electric motor 22b is repeated to turn the valve 3 to the target position. The electric motor 22b is controlled to move.

Next, the operation of the exhaust pipe valve device 11 by the controller 24 will be described. [During Non-operation] The control pulse generation circuit 41 of the controller 24 sends a control pulse signal a having a pulse width corresponding to the output voltage of the position (angle) sensor 23 at the non-operation position (fully open position) to the adder 47. Output. At this time, the A / D converter 46 basically outputs the conversion pulse signal d having the same energization time in response to the control pulse signal a, but the control pulse signal a and the conversion pulse signal Since a small difference occurs between the signal d and the signal d, the adder 47 generates an output pulse signal e having a small pulse width, and the amplifier 48 thereby generates the motor drive pulse current f having a small pulse width. appear. Thus, the electric motor 22b is slightly vibrated to the extent that the electric motor 22b is operated and the rotary shaft 6 of the valve 3 is slightly vibrated.

[Operation] For example, in the case of operating as a warm air halve, each output from the engine speed detection sensor 51, the accelerator opening sensor 52, the cooling water temperature sensor 53, and the exhaust gas pressure sensor 54 is provided to the controller 24. Signals are input, and based on these signals, a target closing degree (set valp position target value) of the valve 3 is determined, and from the control pulse generation circuit 41, as shown in FIG. , And outputs a control pulse signal a corresponding thereto to the adder 47.

Assuming that the valve position target value is, for example, the valve half-closed position, the control pulse signal a having the same energization time (eg, 3.3 msec) as the energization time at the half-closed position in FIG. Is output to The A / D converter 46 generates a converted pulse signal d from the position signal c (output voltage) of the position sensor 23 based on the conversion line A in FIG. For example, when the position sensor 23 is at the fully open position, the conversion pulse signal d for the energization time (for example, 2.4 msec) at the fully open position in FIG.
Is output to the adder 47. The value of the energization time shown in FIG. 8 is an example, and the present invention is not limited to this.

The adder 47 outputs an output pulse signal e to the amplifier 48 based on the difference between the control pulse signal a and the converted pulse d, as shown in FIG.
At this time, since the position sensor 23 is located at a position distant from the target position, the difference is large and an output pulse having a large pulse width is output. Therefore, the amplifier 48 outputs a motor drive pulse current f having a large pulse width to the electric motor 22b, so that the motor 22b rotates with a large output torque to rotate the valve 3. FIG. 1 shows an example of a motor drive pulse current f having the pulse width.
0 (d).

With the rotation of the valve 3, as the position of the position sensor 23 approaches the set target value, the pulse width of the motor drive pulse current f gradually decreases, and the motor 3 rotates with a small output torque. I will be.
When the position sensor 23 reaches the target position, the difference between the control pulse signal a and the converted pulse signal d disappears,
The output pulse signal e from the adder 47 is no longer output, and the electric motor 22b stops. In this case, the electric motor 22b overshoots due to inertia or the like. However, the overshoot is caused by the forward / reverse circuit of the power driver 48b in FIG. That is, the electric motor 22b
Overshoots, the energizing time of the converted pulse signal d becomes longer than the energizing time of the control pulse signal a, so that the difference becomes negative, and the output pulse signal e output from the adder 47 becomes A signal in a direction opposite to the driving direction of the electric motor 22b is generated, and the electric motor 22b operates in the reverse direction to converge to the target position.

Although the case where the valve 3 is operated from the fully open position to the closed position has been described above, when the valve 3 is operated from the closed position to the fully open position, the control pulse signal a Since the energizing time of the converted pulse signal d is longer than the energizing time of the above, the sign of the output pulse signal e becomes negative, and the electric motor 22b is driven to rotate in the reverse direction and returns to the fully open position.

At this time, the control pulse signal a
And the converted pulse signal d, there is a slight difference, so that the rotation shaft 6 of the valve 3
Vibrates slightly in the rotating direction.

Here, the effect of the switching frequency (period) of the control pulse signal a will be described. 1) The switching frequency is less than 100 Hz (period: 1)
0 ms), as shown in FIG.
The minute vibration width is too large, and the vibration of the valve 3 becomes too large, and the sliding portion of the valve 3 between the valve body 5 and the rotating shaft 6 becomes worn or damaged. In other words, fluctuations in exhaust pressure and fretting wear on the valve element 5 and the rotating shaft 6 are induced.

2) The switching frequency is 150 Hz
In the case of exceeding (period: less than 6.7 ms), as shown in FIG. Too much, the valve 3 hardly vibrates. Therefore, the valve body 5 of the valve 3 and the rotating shaft 6
There is no remarkable effect of preventing the sticking or the movement of the sticking. 3) Therefore, as shown in FIG. 11A, the switching frequency (period) is preferably set to 100 to 150 Hz (period is 6.7 to 10 ms). Appropriate, the dither effect becomes noticeable.

Note that the technology of the present invention is not limited to the technology in the above-described embodiment, but may be implemented by means of other modes that perform the same function. Various changes and additions are possible.

[0046]

As is apparent from the above description, according to the control method of the exhaust pipe valve device of the present invention, the actuator of the exhaust pipe of the engine is provided with an electric motor with a speed reducer for rotating a valve body via a rotary shaft. A motor, a position sensor that detects a rotation position of the valve element, and a rotation target position of the valve element, and a position signal from the position sensor and a target position signal of the rotation target position. A controller for driving the electric motor by PWM (Pulse Width Modulation) control so that the rotation position of the valve body becomes the rotation target position based on the difference. When the moving position reaches the target rotation position, the rotation shaft and the valve are controlled via the electric motor based on a minute deviation between the signal of the rotation position of the valve body and the signal of the target rotation position. In the body, said PWM Since the vibration of the switching frequency is provided in the control, during operation, the valve body and the rotating shaft and the valve housing are prevented from sticking or frictional effects due to exhaust gas, and the movement is smooth and accurate. There is an excellent effect that the position control can be performed. As a result, in the sticking and friction parts,
Soot clogging and rusting due to exhaust gas can be prevented, and the responsiveness of the exhaust pipe valve device can be improved and hysteresis can be reduced.

Further, in controlling the exhaust pipe valve device of the present invention, at the time of its operation, control is performed based on the engine cooling water temperature, the exhaust gas pressure, the engine speed, etc., in addition to the accelerator opening, thereby further driving the vehicle. There is an effect that more accurate and precise control can be performed according to the state or the engine state.

[Brief description of the drawings]

FIG. 1 is a perspective view showing an entire exhaust pipe valve device according to an embodiment of the present invention.

FIG. 2 is a longitudinal sectional view in which a part of the exhaust pipe valve device of the present embodiment is broken.

FIG. 3 is a right side view of FIG. 2;

FIG. 4 is a cross-sectional view at the time of valve operation along line IV-IV in FIG. 2;

FIG. 5 is a sectional view taken along line VV of FIG. 2;

FIG. 6 is a control block diagram showing a control system of a controller that drives and controls an electric motor with a speed reducer of an actuator in the exhaust pipe valve device of the present embodiment.

FIG. 7 is a diagram illustrating a relationship between an output voltage (analog signal) and a valve position (angle) of the position sensor.

FIG. 8 shows a relationship between an output signal from a position sensor and a converted pulse signal which is converted into a digital signal and output in accordance with a valve position target value output from a valve position target value setting circuit. It is a conversion characteristic figure of a converter.

FIG. 9 is a block diagram showing a digital servo control system based on PWM (pulse width modulation) control.

FIG. 10 is a diagram showing a pulse signal at the time of operation in each section in the controller. FIG. 10A is a waveform diagram of a control pulse signal output from a control pulse generation circuit to an adder;
FIG. 10B is a waveform diagram of a converted pulse signal output from the A / D converter to the adder, and FIG. 10C is a waveform diagram of an output pulse signal output from the adder to the amplifier.
(D) is a waveform diagram of a motor drive pulse current output from the amplifier to the electric motor.

11A and 11B are diagrams illustrating a change in minute vibration at a valve target position of the electric motor when a switching cycle in the PWM control is changed. FIG. 11A illustrates a case where the switching frequency (cycle) is 100 to 100%. 150Hz
FIG. 11B is a diagram showing the rotation angle fluctuation of the electric motor when the period is 6.7 to 10 ms. FIG. 11B shows the case where the switching frequency (period) is less than 100 Hz (period: more than 10 ms). FIG. 11 (c) is a diagram showing the rotation angle fluctuation of the electric motor at the time, and FIG.
FIG. 7 is a diagram showing a rotation angle fluctuation of the electric motor when the frequency exceeds 150 Hz (period: less than 6.7 ms).

FIG. 12 is a partially cutaway front view of a conventional exhaust pipe valve device.

FIG. 13 is a side view in which a part of FIG. 12 is cut away.

[Explanation of symbols]

 DESCRIPTION OF SYMBOLS 1, 11 Exhaust pipe valve device 2 Exhaust passage 3 Valve 4 Valve housing 4a Internal passage 5 Valve 6 Rotating shaft 7 Actuator 22 Electric motor with reduction gear 22a Reduction output shaft 22b Electric motor 22c Reduction gear 23 Position sensor 24 Controller 31 Connection mechanism Unit 32 finned coupling 35 torsion spring 40 valve position target value setting circuit 41 control pulse generation circuit 45 motor drive control circuit 46 A / D converter 47 adder 48 amplifier 51 engine speed detection sensor 52 accelerator opening sensor 53 cooling Water temperature sensor 54 Exhaust gas pressure sensor 55 Warm air switch 56 Exhaust brake switch 57 Clutch switch a Control pulse signal c Position signal (analog position signal) d Conversion pulse signal e Output pulse signal f Motor drive pulse signal Flow

Claims (3)

[Claims] 1. A valve housing provided in an exhaust pipe of an engine and forming a part of an exhaust passage thereof, a valve body fixed to a rotating shaft rotatably supported in the valve housing, An actuator for rotating a rotating shaft, and for controlling an exhaust pipe valve device that opens and closes the exhaust passage by rotating the valve body by the operation of the actuator; An electric motor with a speed reducer for rotating the valve body, a position sensor for detecting a rotation position of the valve body, and a rotation target position of the valve body, and a position signal from the position sensor. PW is set so that the rotation position of the valve body becomes the rotation target position based on the difference between the rotation target position and the target position signal.
A controller for driving the electric motor by M (pulse width modulation) control. When the rotation position of the valve body reaches the rotation target position, a signal of the rotation position of the valve body is provided by the controller. And the minute deviation between the signal of the rotation target position and the rotation shaft and the valve body via the electric motor.
A method of controlling an exhaust pipe valve device, characterized in that vibration of a switching frequency in control is provided. 2. The controller according to claim 1, further comprising a valve position target value setting circuit having a control pulse generation circuit, a motor drive control circuit including an A / D converter, an adder, and an amplifier. A control pulse signal that is set in accordance with the magnitude of the target closing degree of the valve body based on output signals from an engine speed detection sensor, an accelerator opening sensor, a cooling water temperature sensor, and an exhaust gas pressure sensor. The A / D converter converts the position signal of the valve element input from the position sensor into a digital pulse signal. The adder controls a control pulse signal from the control pulse generation circuit. The difference from the converted pulse signal from the A / D converter is taken, and the difference is defined as the energizing time, and the switching frequency is the same as the switching frequency of the control pulse signal. 2. The control of the exhaust pipe valve device according to claim 1, wherein one pulse signal is output, and the amplifier outputs power for driving the electric motor based on the pulse signal from the adder. 3. Method. 3. The method according to claim 1, wherein a switching frequency of the control pulse signal is 100 to 150 Hz.