JP2005299514A - Exhaust gas recirculation valve controller - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To accurately detect an abnormality such as the inclusion of foreign matter in an EGR valve controller. <P>SOLUTION: The EGR valve comprises a return spring imparting a preload for moving a valve shaft having a valve element in a valve element opening direction or a valve element closing direction, a motor shaft disposed oppositely to the valve shaft and imparting an opposite force opposed to the preload, and a motor 13 driving the motor shaft. When the valve element is at a closed position or an open position, a specified clearance is formed between the valve shaft and a drive shaft, and the moving limit of the motor shaft is specified as a stopper position in the valve element opening direction or the valve element closing direction. The EGR valve controller 10 comprises a valve abnormality detection device 20. When the motor shaft is at a stopper position, the valve abnormality detection device measures the amount of movement when the drive shaft is moved until it touches the valve shaft, compares the amount of the movement with the clearance, and determines the abnormality of the EGR valve according to the result of the comparison. <P>COPYRIGHT: (C)2006,JPO&NCIPI

Description

  The present invention relates to an exhaust gas recirculation valve control device (hereinafter referred to as EGR) that is used when opening / closing control of an exhaust gas recirculation valve (hereinafter referred to as an EGR (Exhaust Gas Recirculation) valve) provided in an exhaust gas recirculation system in a vehicle. In particular, the present invention relates to an EGR valve control device for detecting an abnormality of the EGR valve.

  Generally, a vehicle is provided with an exhaust gas recirculation passage that communicates an exhaust passage from an engine and an intake passage, and an EGR valve for opening and closing the exhaust gas recirculation passage is disposed in the exhaust gas recirculation passage. When controlling the EGR valve, for example, the engine controller unit (hereinafter referred to as ECU) controls the driving of the motor, and controls the opening and closing of the valve body (valve body) by driving the motor to open the exhaust gas recirculation passage. Control the degree.

  By the way, in the EGR valve, foreign matter such as deposits may be caught between the valve body and the valve seat due to the passage of the engine exhaust therein, and when such a situation occurs, the valve body The seat cannot be securely seated on the seat, that is, the EGR valve is not fully closed, and the exhaust gas is recirculated even during idling, for example, and the engine becomes unstable. Therefore, it is necessary to detect an abnormal state in which the valve body cannot be seated on the valve seat.

  Conventionally, even if an abnormality occurs in the EGR valve, in order to surely shift to the fully closed state, a sensor for detecting the flow rate passing through the flow rate control valve and a synchronous flow rate control valve incorporating a spring are provided. In the case of an abnormality in the flow control valve, a special drive frequency signal is given to the control valve drive means so that the flow control valve is operated by a spring force biased in the valve closing direction. When the valve resistance increases and the required valve closing force cannot be maintained, that is, when the valve cannot be driven to close, it is determined that an abnormality has occurred in the valve (see, for example, Patent Document 1).

  In addition, as the EGR valve, there is a fail in which the valve cannot be seated using a member that can be hooked on the valve shaft only in the valve closing direction while leaving the play necessary for initialization in the seated state of the valve. It is determined whether or not the mode has been reached, and when the fail mode is entered, a valve closing direction driving amount equal to or more than the valve closing direction driving amount corresponding to the above play is given to the stepping motor to drive the rotor shaft. Here, when determining the fail mode, it is determined whether the suction mode is the fail mode by detecting the suction negative pressure or the discharge portion temperature of the EGR valve (for example, Patent Document 2). reference).

JP-A-8-177580 (paragraph (0013) to paragraph (0043), FIGS. 1 to 9) Japanese Patent No. 3204043 (pages 3 to 5, FIGS. 1 to 4)

  Since the conventional EGR valve control device is configured as described above, simply detecting whether or not an abnormality has occurred in the valve in accordance with the valve closing resistance causes a gap between the valve body and the valve seat. In the situation where foreign matter such as deposit is caught in the valve body and the valve body cannot be seated on the valve seat, the valve closing resistance may not increase, and there is a problem that the valve abnormality cannot be detected accurately.

  Further, in the conventional EGR valve control device, when the fail mode is determined, the fail mode is determined according to the detection result of the suction negative pressure or the discharge portion temperature, and therefore, between the valve body and the valve seat. In a situation where foreign matter such as deposit is caught and the valve body cannot be seated on the valve seat, the suction negative pressure or the discharge part temperature may not change so much, and similarly, the valve abnormality cannot be detected accurately. There was a problem.

  The present invention has been made to solve the above-described problems, and an object of the present invention is to obtain an EGR valve control device that can always detect an abnormality of an EGR valve with high accuracy.

  An EGR valve control device according to the present invention is arranged so as to face a valve shaft, a preload applying means for applying a preload for moving a valve shaft provided with the valve body in a valve opening direction or a valve closing direction of the valve body. The open / close control of the exhaust gas recirculation valve having a drive shaft that applies a counter force opposing the applied pressure to the valve body is performed by driving the drive shaft with a drive source. When the valve body is in the valve closing position or the valve opening position, a predetermined clearance is defined between the valve shaft and the drive shaft, and the movement limit of the drive shaft in the valve opening direction or the valve closing direction is the stopper position. It is prescribed as When the drive shaft is in the stopper position, the EGR valve control device moves the drive shaft until it abuts the valve shaft and measures the amount of movement. And determining means for determining an abnormality of the exhaust gas recirculation valve in accordance with the comparison result.

  According to the present invention, the clearance and the drive shaft movement amount are compared, and based on the comparison result, it is determined whether or not the valve operation is normal. Therefore, in the EGR valve, the valve body and the valve seat Even when foreign matter such as deposit is caught between the two, there is an effect that the valve operation abnormality can be detected with high accuracy.

Embodiment 1 FIG.
FIG. 1 shows an EGR valve control apparatus according to Embodiment 1 for carrying out the present invention. In FIG. 1, an illustrated EGR valve control device (hereinafter simply referred to as a control device) 10 includes a controller 11, a motor drive circuit (hereinafter simply referred to as a drive circuit) 12, a valve drive motor (drive source) 13, and an EGR valve. A valve position sensor 14 for detecting the position (not shown in FIG. 1) and a valve abnormality detection device 20 are provided.

  The valve abnormality detection device 20 includes a valve shaft contact position detection unit 21, a movement amount measurement unit 22, a stopper contact position detection unit 23, a clearance setting storage unit (storage unit) 24, and a valve shaft abnormality determination unit 25. Have.

  As shown in the figure, the control device 10 is given a target position that designates the valve position (opening degree) as a target position signal. On the other hand, the valve position sensor 14 includes, for example, a movable contact portion (not shown) that moves on a resistor (not shown) to which a constant voltage is applied. It moves according to the rotation of the rotor, and a voltage according to the moving position of the motor shaft described later is output from the movable contact portion as a valve position signal indicating the position of the EGR valve.

  The valve position signal output from the valve position sensor 14 is given to the subtractor 15, and a deviation between the target position signal and the valve position signal is obtained by the subtracter 15, and this deviation is given to the controller 11. Then, the controller 11 generates a PWM control signal corresponding to the deviation and gives the PWM control signal to the drive circuit 12. In the drive circuit 12, the valve drive motor 13 is driven and controlled by PWM control in accordance with the PWM control signal, and the EGR valve is driven by the valve drive motor 13 to change its opening.

  Specifically, for example, the controller 11 obtains the PI control amount according to the above-described deviation, obtains the drive duty based on the PI control amount, and applies this drive duty to the drive circuit 12 as a PWM control signal. It will be. The drive circuit 12 turns on and off the voltage applied to the valve drive motor 13 in accordance with the PWM control signal at a predetermined cycle, and according to the ratio of the on time to the off time per cycle (drive duty: PWM control signal). The voltage is controlled by the PWM signal.

  Referring now to FIG. 2, FIG. 2 is a cross-sectional view schematically showing the EGR valve 30, and the EGR valve 20 is disposed in a vehicle exhaust gas recirculation system. The EGR valve 30 includes a valve housing 31, and a passage 32 that defines a part of the exhaust gas recirculation passage is defined in the valve housing 31. A motor case 33 is disposed at the upper end of the EGR valve 30, and the valve drive motor 13 is accommodated in the motor case 33.

  Although not shown, the valve drive motor 13 has a rotor around which a coil is wound and a yoke having a magnet. A motor shaft 34 is screwed to the rotor, and the rotor is rotated according to the rotation of the rotor. The motor shaft 34 moves in the vertical direction in the figure. Further, although not shown, a motor stopper is disposed in the valve drive motor 13, and the upper limit movement position of the motor shaft (drive shaft) 34 is regulated by the motor stopper. That is, when the motor shaft 34 moves up to the position of the motor stopper, its movement is restricted.

  The upper end of the valve shaft 35 is positioned corresponding to the lower end of the motor shaft 34, and this valve shaft 35 extends in the valve housing 31 in the vertical direction in the figure. The valve shaft 35 is guided to the valve housing 31 by a guide seal 36 and a guide plate 37 so as to be vertically movable. A control valve (valve body) 38 and a guide seal cover 39 are attached to the valve shaft 35.

  A spring seat 40 is disposed at the upper end of the valve shaft 35, and a return spring 41, which is a biasing means, is disposed between the spring seat 40 and the guide plate 37. 35 is urged in the upward direction, that is, the closing direction of the control valve 38, and the control valve 38 is in contact with (is seated on) the valve seat (valve seat) 42.

  In the illustrated EGR valve 30, a predetermined preload (return torque) is applied in the valve closing direction of the control valve 38 by the return spring 41, and the control valve 38 is opened in response to energization of the valve drive motor 13. Motor torque is applied in the direction, and the valve shaft 35, that is, the control valve 38 is driven by the torque balance between the preload and the motor torque, and the passage 32 is controlled to open and close.

  When the control valve 38 moves upward and comes into contact with the valve seat 42, the passage 32 (that is, the exhaust gas recirculation passage) is closed, and when the control valve 38 moves downward and leaves the valve seat 42, the exhaust gas is exhausted. The reflux passage will be opened.

  Alternatively, a pre-pressure may be applied in the valve opening direction of the control valve 38 by the return spring 41, and a motor torque may be applied in the valve closing direction of the control valve 38 by the valve drive motor 13.

  Referring also to FIG. 3, FIG. 3 is a diagram showing a distance (clearance) between the motor shaft 34 and the valve shaft 35 when the control valve 38 is seated on the valve seat 42, and the control valve 38 is seated on the valve seat 42. In this state, a predetermined clearance Dc exists between the motor shaft 34 and the valve shaft 35. However, when foreign matter such as deposit is caught between the control valve 38 and the valve seat 42, the control valve 38 is not closed by the amount of the foreign matter (the control valve 38 is not seated on the valve seat 42), that is, The valve shaft 35 does not rise to the specified position, and the clearance Dc changes.

  Despite the target position signal indicating the fully closed position of the control valve 38, the engine may become unstable if the control valve 38 does not sit on the valve seat 42 and the exhaust gas circulates in the recirculation system. is there. Therefore, it is necessary to accurately detect a state in which the control valve 38 is not completely seated on the valve seat 42 due to foreign matter or the like (hereinafter referred to as valve abnormality).

Next, the operation will be described.
1 and 4, in the EGR valve control device 10 shown in FIG. 1, a valve position signal is given to the valve abnormality detection device 20. Now, when the control valve 38 (FIG. 2) is fully closed, the motor shaft 34 is driven in the valve closing direction (the upward direction in FIG. 2) by the valve drive motor 13 (step ST1).

  The stopper contact position detector 23 detects whether or not the motor shaft 34 has contacted the motor stopper (step ST2), and the motor shaft 34 has reached the motor stopper position by the stopper position contact detector 23. When this is detected, the controller 11 reversely rotates the valve drive motor 13 to drive the motor shaft 34 in the valve opening direction (step ST3).

  On the other hand, when the motor shaft 34 reaches the position of the motor stopper, the movement amount measuring unit 22 starts measuring the movement amount of the motor shaft 34 according to the valve position signal (step ST4). The valve shaft contact position detector 21 detects whether or not the motor shaft 34 and the valve shaft 35 are in contact (step ST5), and detects that the motor shaft 34 and the valve shaft 35 are in contact. Then, the movement amount measuring unit 22 sets the movement amount at that time as the motor shaft movement amount Dm.

  The clearance Dc is set in the clearance setting storage unit 24, and the subtractor 26 obtains a deviation (Dm−Dc) between the motor shaft movement amount Dm and the clearance Dc. The deviation (Dm−Dc) is sent to the valve shaft abnormality determination unit 25.

  The valve shaft abnormality determination unit 25 determines whether or not the deviation (Dm−Dc) is larger than a predetermined threshold (allowable value) (step ST6), and if the deviation (Dm−Dc)> the threshold, Is detected between the control valve 38 and the valve seat 42, and a valve closing abnormality is detected (step ST7). Then, the valve shaft abnormality determining unit 25 sends a valve closing abnormality signal to the controller 11. On the other hand, if the deviation (Dm−Dc) ≦ the threshold value, the valve shaft abnormality determining unit 25 detects that the valve is closed and sends a valve closing normal signal to the controller 11 (step ST8).

  In this way, the deviation between the predetermined clearance Dc and the motor shaft movement amount Dm is obtained, and if this deviation is less than the allowable value, it is determined that the valve closing operation is normal. In FIG. 30, even when a foreign object is caught between the control valve 38 and the valve seat 42, the valve closing abnormality can be detected with high accuracy.

  By the way, the above-mentioned clearance Dc is not only slightly different for each EGR valve due to the accuracy variation of each part, but may change over time due to wear of the parts. Therefore, in the EGR valve control device 10 shown in FIG. 1, for example, when the main power supply is turned on, the motor shaft 34 is moved from the valve closing position to the valve opening direction as described above, and the valve shaft 35 and The amount of movement of the motor shaft until contact is measured, and this amount of movement may be stored in the clearance setting storage unit 24 as the clearance Dc.

  That is, in the EGR valve control device 10, when the main power supply is turned on, the controller 11 drives the valve drive motor 13 to drive the motor shaft 34 from the valve closing position, and the movement amount measuring unit 22 uses the valve position signal. The amount of movement is measured in accordance with the amount of movement, and the amount of movement at the time when the contact between the valve shaft 35 and the motor shaft 34 is detected by the valve shaft contact position detection unit 21 is stored in the clearance setting storage unit 24 as the clearance Dc. To do.

  The clearance Dc may be stored when the main power is turned off. In this case, when the main power is turned off, the EGR valve control device 10 stores the clearance Dc. After the operation is performed, the power supply is turned off.

  As is clear from the above description, the valve shaft contact position detection unit 21, the movement amount measurement unit 22, the stopper contact position detection unit 23, the controller 11, and the motor drive circuit 12 collectively measure the movement amount. The valve shaft abnormality determination unit 25 and the subtractor 26 function as a determination unit.

  As described above, according to the first embodiment, when the control valve is in the valve closing position or the valve opening position, the predetermined clearance is defined between the valve shaft and the motor shaft, and the valve opening direction or the valve closing direction is determined. If the motor shaft movement limit is defined as the stopper position in the direction, and the motor shaft is in the stopper position, the motor shaft is moved until it contacts the valve shaft and the amount of movement is measured. Since the EGR valve abnormality is determined according to the comparison result, even when a foreign object is caught between the control valve and the valve seat, the valve closing abnormality can be accurately detected. In this case, if the deviation between the movement amount of the valve shaft and the clearance exceeds a predetermined allowable value, it is determined that the EGR valve is abnormal. If so, it is possible to easily perform the EGR valve abnormality determination.

  According to the first embodiment, when the main power source is turned on or off, the motor shaft is driven from the stopper position until it contacts the valve shaft, the amount of movement is measured, and the amount of movement is stored as a predetermined clearance. Thus, there is an effect that it is possible to cope with the aging due to the change in the clearance due to the accuracy variation of each part of the EGR valve and the wear of the parts.

Embodiment 2. FIG.
FIG. 5 is a diagram showing an example of the EGR valve 50 used in the second embodiment of the EGR valve control apparatus according to the present invention. In FIG. 5, the same components as those in FIG. Will be omitted.

  In the example shown in FIG. 5, one end of the connecting member 51 is attached to the lower end side of the motor shaft 34 so as to surround the lower end of the motor shaft 34. The other end (tip) of the connecting member 51 is formed with a passage port 51a that allows passage of the valve shaft 35. The tip portion (valve shaft head) 35a of the valve shaft 35 has a diameter larger than that of the passage port (passage portion) 51a. It is formed in a large truncated cone shape.

  Referring to FIG. 6, FIG. 6 is a view showing a clearance between the motor shaft 34 and the valve shaft 35 when the control valve 38 is seated on the valve seat 42 in FIG. 5, and the control valve 38 is seated on the valve seat 42. In the state, a predetermined clearance Dc1 exists between the motor shaft 34 and the valve shaft 35. In addition, a clearance (additional clearance) Dc2 exists between the lower surface of the valve shaft head 35a of the valve shaft 35 and the inner surface (front end upper surface) of the connecting member 51.

  In the EGR valve 50 shown in FIG. 5, when the motor shaft 34 is driven in the valve closing direction to close the control valve 38, the motor shaft 34 and the valve shaft 35 (that is, the valve shaft head 35a) are interposed between them. When an interval exceeding Dc1 + Dc2 occurs, the tip of the connecting member 51 comes into contact with the lower end of the valve shaft head 35a, and a force in the valve closing direction is applied from the motor shaft 34 to the valve shaft 35 via the connecting member 51.

  As described above, in the EGR valve 50, even if a sliding load exceeding the preload by the return spring 41 is generated and the movement of the valve shaft 35 is affected, the valve shaft 35 is connected from the motor shaft 34 via the connecting member 51. Therefore, the valve shaft 35 can be driven in the valve closing direction. That is, in the EGR valve 50, the valve shaft 35 can be driven in the valve closing direction up to the preload of the return spring 41 + the sliding load of the maximum thrust of the valve drive motor.

  Also in the above-described EGR valve 50, when a foreign object is caught between the control valve 38 and the valve seat 42, the control valve 38 is not controlled even though the target position signal indicates the fully closed position of the control valve 38. If the exhaust gas circulates in the recirculation system without being seated on the valve seat 42, the engine becomes unstable.

  In other words, in the EGR valve 50, when the motor shaft 34 is moved in the valve closing direction and the control valve 38 is closed, the motor shaft 34 stops at the position of the motor stopper and closes normally if no foreign matter or the like is caught. If the valve is operated but foreign matter is caught, the clearance Dc2 is exceeded and the movement of the valve shaft 35 is abnormal (the clearance Dc2 is exceeded and the valve closing position is abnormal), the connecting member 51 The motor shaft 34 is restrained (stopped) at a position where the tip of the valve contacts the valve shaft head 35a, and the valve drive motor 13 is locked.

  Therefore, here, valve abnormality detection was performed as follows. When detecting an abnormality of the EGR valve 50, a control system similar to the EGR valve control device 10 shown in FIG. 1 is used, but here, the clearance Dc1 is set in the clearance setting storage unit 24. In place of the stopper contact position detector 23, a motor lock detector (not shown) is used.

  Referring to FIGS. 1, 5, and 7, when the control valve 38 is fully closed, the motor shaft 34 is driven in the valve closing direction (upward direction in FIG. 5) by the valve drive motor 13. (Step ST9).

  The motor lock detection unit detects whether or not the valve drive motor 13 is locked (for example, when a current exceeding a predetermined current flows through the valve drive motor 13, the motor lock is detected: step ST10). When the lock of the valve drive motor 13 is detected by the lock detector, the controller 11 reversely rotates the valve drive motor 13 to drive the motor shaft 34 in the valve opening direction (step ST11).

  On the other hand, when the motor shaft 34 is driven in the valve opening direction, the movement amount measuring unit 22 starts measuring the movement amount of the motor shaft 34 according to the valve position signal (step ST12). The valve shaft contact position detector 21 detects whether or not the motor shaft 34 and the valve shaft 35 are in contact (step ST13), and detects that the motor shaft 34 and the valve shaft 35 are in contact. Then, the movement amount measuring unit 22 sets the movement amount at that time as the motor shaft movement amount Dm.

  The subtractor 26 obtains a deviation (Dm−Dc1) between the motor shaft movement amount Dm and the clearance Dc1. The deviation (Dm−Dc1) is sent to the valve shaft abnormality determination unit 25. The valve shaft abnormality determining unit 25 determines whether or not the deviation (Dm−Dc1) is larger than a predetermined threshold (allowable value) (step ST14), and if the deviation (Dm−Dc1)> the threshold, It is determined that the valve has been caught between the control valve 38 and the valve seat 42, and a valve closing abnormality is detected (step ST15). Then, the valve shaft abnormality determining unit 25 sends a valve closing abnormality signal to the controller 11. On the other hand, if (Dm−Dc1) ≦ threshold, the valve shaft abnormality determining unit 25 detects that the valve is closed and sends a valve closing normal signal to the controller 11 (step ST16).

  In this way, when the valve drive motor 13 is locked, the deviation between the clearance Dc1 and the motor shaft movement amount Dm is obtained, and if this deviation is less than the allowable value, it is determined that the valve closing operation is normal. Therefore, even when a foreign object is caught between the control valve 38 and the valve seat 42 in the EGR valve 50, the valve closing abnormality can be detected with high accuracy.

  Referring to FIG. 8, when the motor shaft 34 is moved in the valve closing direction and the sliding load applied to the valve shaft 35 exceeds the preload of the return spring 41, the valve shaft 34 is moved to the return spring 41. It is not driven by the pre-pressure (fixing start: P1), and as described above, the tip of the connecting member 51 is in contact with the valve shaft head 35a (connection start: P2), and the valve shaft 35 is driven by the motor shaft 34. Will be driven.

  In the above-described state, even if the motor shaft 34 moves to the target position as shown by the curve L1, that is, moves to the position of the motor stopper, the valve shaft 35 becomes (Dc1 + Dc2) as shown by the curve L2. Therefore, the control valve 38 is not seated on the valve seat 42 even though the valve target position signal indicates that the valve is fully closed. End up.

  Therefore, here, the valve target position signal is corrected as follows. Although not shown, when the sliding load of the valve shaft 34 exceeds the pre-pressure of the return spring 41 (for example, when detecting that the load applied to the valve drive motor 13 has increased), the upper control unit (generating means: not shown) 1), (Dc1 + Dc2) is added to the target position to generate a corrected target position, and this corrected target position is given to the subtracter 15 shown in FIG. 1 as a valve target position signal.

  As a result, in FIG. 9, the motor shaft 34 moves to the correction target position as indicated by the curve L3, and this correction target position is larger than the target position by (Dc1 + Dc2). As shown by the curve L4, the connecting member 51 is driven to the target position. When it is confirmed by the valve position signal that the motor shaft 34 has reached the correction target position, the host control unit gives the original target position as a valve target position signal instead of the correction target position. The drive motor 13 is controlled to return the motor shaft 34 to the target position.

  As is clear from the above description, the controller 11, the drive circuit 12, and the subtractor 15 collectively function as drive control means.

  As described above, according to the second embodiment, the EGR valve is provided with the connecting member that connects the motor shaft and the valve shaft when the sliding load of the valve shaft exceeds the preload of the preload applying means. When the valve drive motor lock is detected, the motor shaft is moved until it comes into contact with the valve shaft, the amount of movement is measured, and the abnormality of the EGR valve is determined according to the deviation between the clearance and the amount of movement. Thus, there is an effect that the abnormality of the EGR valve can be detected with high accuracy.

  According to the second embodiment, when the valve shaft is driven in the valve opening direction or the valve closing direction, if the sliding load of the valve shaft increases more than the preload by the preload applying means, the target movement position of the motor shaft is set. The corrected target movement position is generated by correcting according to the clearance and the additional clearance, and the drive shaft is driven and controlled according to the corrected target position. Therefore, even if the sliding load increases, the target position can be accurately obtained. There is an effect that the valve shaft can be driven and controlled.

1 is a block diagram illustrating an exhaust gas recirculation valve control device according to Embodiment 1 of the present invention. FIG. It is sectional drawing which shows roughly the structure of an example of the exhaust gas circulation valve controlled by the exhaust gas recirculation valve control apparatus shown in FIG. It is sectional drawing which expands and shows a part of exhaust gas recirculation valve | bulb shown in FIG. It is a flowchart for demonstrating the valve abnormality determination operation | movement in the exhaust gas recirculation valve control apparatus by Embodiment 1 of this invention. It is sectional drawing which shows roughly the structure of an example of the exhaust gas recirculation valve controlled by the exhaust gas recirculation valve control apparatus by Embodiment 2 of this invention. It is sectional drawing which expands and shows a part of exhaust gas recirculation valve | bulb shown in FIG. It is a flowchart for demonstrating the valve abnormality determination operation | movement in the exhaust gas recirculation valve control apparatus by Embodiment 2 of this invention. It is a figure which shows the example at the time of drive-controlling the valve shaft of the exhaust gas recirculation valve shown in FIG. 5 according to the target position. It is a figure which shows the example at the time of drive-controlling the valve shaft of the exhaust gas recirculation valve shown in FIG. 5 according to a correction | amendment target position.

Explanation of symbols

  DESCRIPTION OF SYMBOLS 10 EGR valve control apparatus, 11 controller, 12 motor drive circuit, 13 valve drive motor, 14 valve position sensor, 15, 26 subtractor, 20 valve abnormality detection apparatus, 21 valve shaft contact position detection part, 22 movement amount measurement Part, 23 stopper contact position detection part, 24 clearance setting storage part, 25 valve shaft abnormality judgment part, 30, 50 EGR valve, 31 valve housing, 32 passage, 33 motor case, 34 motor shaft, 35 valve shaft, 35a valve Shaft head, 36 guide seal, 37 guide plate, 38 control valve (valve body), 39 guide seal cover, 40 spring seat, 41 return spring, 42 valve seat, 51 connecting member, 51a passage (passage).

Claims (6)

A preload applying means for applying a preload for moving a valve shaft provided with the valve body in a valve opening direction or a valve closing direction of the valve body, and an opposition disposed opposite to the valve shaft and facing the preload. In an exhaust gas recirculation valve control device that performs open / close control of an exhaust gas recirculation valve having a drive shaft that applies force to the valve body by drivingly controlling the drive shaft by a drive source
When the valve body is in the valve closing position or the valve opening position, a predetermined clearance is defined between the valve shaft and the drive shaft,
The movement limit of the drive shaft in the valve opening direction or the valve closing direction is defined as a stopper position,
When the drive shaft is at the stopper position, a movement amount measuring means that moves the drive shaft until it contacts the valve shaft and measures the movement amount;
An exhaust gas recirculation valve control apparatus comprising: a determination unit that compares the movement amount with the clearance and determines an abnormality of the exhaust gas recirculation valve according to the comparison result.   2. The exhaust gas recirculation according to claim 1, wherein the determination means determines that the exhaust gas recirculation valve is abnormal when a deviation between a movement amount of the valve shaft and a clearance exceeds a predetermined allowable value. Valve control device. When the main power is turned on or off, the movement amount measuring means drives the drive shaft from the stopper position until it contacts the valve shaft, and measures the movement amount.
The exhaust gas recirculation valve control device according to claim 1 or 2, further comprising storage means for storing the movement amount as a predetermined clearance. The exhaust gas recirculation valve is provided with a connecting member for connecting the drive shaft and the valve shaft when the sliding load of the valve shaft exceeds the preload of the preloading means,
Having a lock detection means for detecting the lock of the drive source;
The movement amount measuring means, when the lock of the drive source is detected by the locking means, moves the drive shaft until it comes into contact with the valve shaft, and measures the movement amount. Item 2. An exhaust gas recirculation valve control device according to Item 1. One end of the connecting member is attached to the drive shaft, and the other end of the connecting member is positioned below the front end of the valve shaft with an additional clearance, and the connecting member passes through the valve shaft excluding the front end. The passage section that allows
When the valve shaft is driven in the valve opening direction or the valve closing direction, if the sliding load of the valve shaft increases more than the preload by the preload applying means, the target movement position of the drive shaft is set to the clearance and the additional clearance. Generating means for generating a corrected target movement position by correcting in response,
5. The exhaust gas recirculation valve control device according to claim 4, further comprising drive control means for driving and controlling the drive shaft in accordance with the correction target position.   6. The exhaust gas recirculation valve control device according to claim 5, wherein the drive control means performs control to drive the drive shaft to the corrected target movement position and then return the drive shaft to the target movement position.

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