JPH11294194A - Control method and device for step motor type valve device - Google Patents

Abstract

PROBLEM TO BE SOLVED: To suitable restrain the occurrence of stepping-out the like due to the reduction in the driving voltage of a step motor in controlling the step motor type valve device. SOLUTION: An intake throttle valve 4 arranged inside an intake passage 2 is driven by a step number control making a reference of a prescribed step position of a step motor 40. When the voltage of a battery to be supplied to the step motor 40 decreases below a prescribed voltage, an electric control device 19 set the target opening value of the intake throttle valve 4 to a value, for instance, corresponding to the full-open position of the same intake throttle valve 4.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a stepping motor type valve device driven to be opened and closed by a stepping motor, and more particularly to a control method and a control device for a valve device suitable for use in an intake throttle valve of a diesel engine.

[0002]

2. Description of the Related Art Since the output adjustment of a diesel engine is mainly performed by controlling the fuel injection amount, conventionally, the intake air amount control has not been required to have very high accuracy. However, in order to meet the increasing demand for emission improvement in recent years, it has become necessary to secure a large amount of EGR through a large amount of exhaust gas recirculation (hereinafter referred to as “EGR”). In order to secure the above EGR amount, it is becoming necessary to precisely control the amount of intake air to the diesel engine itself. In order to enable such fine control of intake air volume, the development of a step motor type intake throttle valve device capable of high-precision opening control independently of the accelerator pedal without interlocking with the accelerator pedal has been promoted. ing.

Such a valve device includes a step motor which is drivingly connected to a shaft of an intake throttle valve, and based on a predetermined step position of the step motor as a reference, based on the number of steps of rotating the motor from that position. The opening degree control is performed by opening and closing the intake throttle valve.

[0004]

In such a device, when the drive voltage (battery voltage) applied to the step motor decreases, the output of the motor also decreases. There is a case where the drive torque at the time of opening and closing drive is insufficient, so-called step-out of the step motor occurs. When the step-out of the step motor occurs, the correspondence between the number of steps and the opening degree of the intake throttle valve cannot be maintained, so that accurate opening control of the intake throttle valve cannot be performed. In particular, in the case of an intake throttle valve of a diesel engine, if the opening control becomes impossible due to step-out of a step motor, a required amount of intake air cannot be supplied, and a problem such as an increase in smoke in exhaust gas may occur. There is also.

[0005] Conventionally, for example, Japanese Patent Application Laid-Open No. 61-22654.
As in the device described in Japanese Patent Publication No. 0, when the drive voltage falls below a predetermined value, the drive speed of the motor is reduced to secure the drive torque, and even when the drive voltage decreases, the valve opening control is performed. Devices for maintaining are also known, but this does not necessarily prevent the occurrence of step-out. That is, since the opening target value of the valve itself changes in accordance with the engine operating state, there is always a possibility that the motor will fall out of step even if the driving speed of the motor is reduced and its driving torque is secured. It should be noted that not only the intake throttle valve described above, but also a step motor type valve device in which the opening degree target value changes according to operating conditions and the like, these facts are generally common.

SUMMARY OF THE INVENTION The present invention has been made in view of the above circumstances, and an object of the present invention is to provide a method of controlling a step motor type valve device capable of suitably suppressing the occurrence of step-out or the like due to a decrease in power of a step motor. And a control device.

[0007]

In order to achieve the above object, the invention according to the first aspect is characterized in that the valve is controlled based on a step number control based on a predetermined step position of a step motor drivingly connected to the valve. A method for controlling a step motor type valve device that opens and closes, wherein a drive voltage of the step motor is monitored, and when the drive voltage is equal to or less than a predetermined voltage, the valve opening target value is set to a fixed value. Make a summary.

[0008] The invention described in claim 2 is the first invention.
In the control method of the step motor type valve device according to the above,
The valve is an intake throttle valve provided in an intake passage of a diesel engine, and the opening target value of the intake throttle valve, which is a fixed value based on the drive voltage of the step motor being equal to or lower than a predetermined voltage, is set to an engine state. The gist is that the value corresponds to the corresponding retreat position.

The invention described in claim 3 is the same as the invention in claim 2
In the control method of the step motor type valve device according to the above,
The gist is that the target value of the opening degree of the intake throttle valve, which is a value corresponding to the evacuation position according to the engine state, is set to the fully opened position of the intake throttle valve or its vicinity.

[0010] Further, the invention according to claim 4 is based on claim 2.
Alternatively, in the control method of the step motor type valve device according to 3, when the system abnormality of the engine or the ignition switch is turned off, the opening target value of the intake throttle valve, which is a value corresponding to the retreat position according to the engine state, is set to the same value. The gist of the present invention is to set the intake throttle valve to a fully closed position or its vicinity.

The invention described in claim 5 is the same as the invention described in claim 2.
In the method of controlling a step motor type valve device according to any one of claims 1 to 4, when opening and closing the intake throttle valve based on the step number control, a predetermined step position of the step motor and an opening degree of the class throttle valve are determined. The relationship is confirmed at the fully open position of the intake throttle valve, and a target opening degree value of the intake throttle valve, which is a value corresponding to the retreat position according to the engine state, is set near the fully open position of the intake throttle valve and The gist is to set a value corresponding to a position at which the confirmation process is not performed.

According to a sixth aspect of the present invention, there is provided a control method of a step motor type valve device for opening and closing the valve based on a step number control based on a predetermined step position of a step motor drivingly connected to the valve device. Monitoring means for monitoring the drive voltage of the step motor, and when the monitored drive voltage is equal to or less than a predetermined voltage, an opening target setting means for setting the opening target value of the valve to a fixed value, The point is to provide

The invention described in claim 7 is the same as the claim 6.
In the control device of the step motor type valve device according to the above,
The valve is an intake throttle valve provided in an intake passage of a diesel engine, and the opening target setting means sets the fixed opening target value of the intake throttle valve to a fixed value corresponding to an evacuation position corresponding to an engine state. And the gist of that.

The invention described in claim 8 is the same as the invention described in claim 7.
In the control device of the step motor type valve device according to the above,
The gist is that the opening degree target value setting means sets the opening degree target value of the intake throttle valve, which is a retreat position equivalent value according to the engine state, to a fully open position of the intake throttle valve or its vicinity. I do.

[0015] The invention according to claim 9 is the same as the invention according to claim 7.
Or the control device for a step motor type valve device according to 8, wherein the opening target value setting means is configured to, when a system abnormality of the engine or an ignition switch is turned off, set a value corresponding to a retreat position corresponding to the engine state. The gist of the invention is that the opening target value of the throttle valve is set to the fully closed position of the intake throttle valve or its vicinity.

According to a tenth aspect of the present invention, in the control device for a step motor type valve device according to any one of the seventh to ninth aspects, when opening and closing the intake throttle valve based on the step number control, Means for confirming the relationship between a predetermined step position of the step motor and the opening degree of the intake throttle valve at a fully open position of the intake throttle valve, wherein the target opening degree setting means is provided in accordance with the engine state. The gist is that the target value of the opening degree of the intake throttle valve, which is the retracted position equivalent value, is a position equivalent to a position near the fully open position of the intake throttle valve and at which the confirmation process is not executed.

According to the method of the first aspect and the configuration of the sixth aspect, when the drive voltage of the step motor decreases, the target value of the opening of the valve is set to a fixed value, thereby opening and closing the valve. , And finally the step motor is controlled to be maintained at a predetermined opening.
By limiting the drive of the step motor when the drive voltage drops and finally prohibiting the drive, the occurrence of step-out or the like of the motor can be suitably suppressed.

A method according to claim 2 and a method according to claim 7.
According to the configuration described in (1), when the drive voltage of the step motor (or the battery voltage in the case of a vehicle-mounted diesel engine) drops, the opening target value of the step motor is set to the retracted position equivalent value, thereby opening and closing the intake throttle valve. By reducing the amount, that is, the driving amount of the step motor as much as possible, it is possible to preferably suppress the occurrence of step-out or the like of the motor. Here, the retracted position is an opening position of the intake throttle valve corresponding to “a value different from the normal target value”. In addition, the retreat position means that it is possible to at least maintain the operation of the diesel engine and suppress the occurrence of malfunctions in a situation where the drive control of the step motor becomes difficult and the opening degree control of the intake throttle valve cannot be sufficiently performed. It is also the opening position of the intake throttle valve.

Further, the method according to claim 3 and the method according to claim 8
According to the configuration described in the above, in a situation where the operation of the engine must be maintained, and when the drive voltage of the step motor decreases, the opening target value of the intake throttle valve is set to the fully open position or in the vicinity thereof. By setting, it becomes possible to continue to secure an intake air amount more than necessary in the combustion chamber of the diesel engine. That is, it is possible to suppress the occurrence of step-out or the like of the step motor without hindering the operation of the diesel engine.

Further, the method according to claim 4 and the method according to claim 9
According to the configuration described in the above, when a system abnormality such as a fuel injection system of a diesel engine occurs, or when an ignition switch is turned off, the target value of the opening degree of the intake throttle valve is set to a fully closed position or in the vicinity thereof. Thus, the intake air supplied to the combustion chamber of the diesel engine can be cut off or significantly reduced. That is, it is possible to suppress the occurrence of step-out or the like of the step motor while stopping the engine promptly.

Furthermore, the method according to claim 5 and the method according to claim 1
According to the configuration described in No. 0, when the drive voltage of the step motor is lowered or when the system of the engine is abnormal, the confirmation process is not executed, so that the drive of the step motor accompanying the confirmation process is prohibited to remove the motor. It is possible to suppress the occurrence of tonality and the like, and prevent erroneous determination at the time of confirmation.

[0022]

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS Hereinafter, an embodiment in which a control method and a control device of a step motor type valve device according to the present invention are applied to a control device of an intake throttle valve of a diesel engine will be described in detail.

First, an outline of a diesel engine provided with a valve device according to the present embodiment will be described with reference to FIG. An intake passage 2 is connected to a combustion chamber 12 of the diesel engine 1 via an intake valve (not shown). An air cleaner 3 for filtering the intake air, a pressure sensor 6 for detecting the pressure (atmospheric pressure) of the intake air, and an intake temperature sensor 78 for detecting the temperature of the intake air are provided in the intake passage 2 from the upstream side. An intake throttle valve 4 for adjusting the amount of intake air introduced into the combustion chamber 12 is provided.

The intake throttle valve 4 is driven to open and close by a step motor 40 and a drive mechanism 5 mainly composed of a gear group for drivingly connecting the step motor 40 and the intake throttle valve 4. The drive of the step motor 40 is controlled by an electronic control unit (hereinafter referred to as “ECU”) 19 for performing various controls of the diesel engine 1. Further, the drive mechanism 5 is provided with a full-open switch 39 which is turned on when the intake throttle valve 4 is located closer to the open side than a predetermined position near the fully open position.

On the other hand, further downstream of the intake throttle valve 4 in the intake passage 2, it branches off from an exhaust passage 7 connected to the combustion chamber 12 via an exhaust valve (not shown) and joins the intake passage 2. EGR (exhaust gas recirculation) passage 8 is connected. The EGR passage 8 is provided with an EGR control valve 9 which is opened and closed by an actuator 10 such as a diaphragm controlled by the ECU 19. The amount of intake air is adjusted by the intake throttle valve 4 and the amount of EGR is adjusted by the EGR control valve 9 to adjust the amount of EG for the amount of intake air introduced into the combustion chamber 12.
The ratio of the R amount, that is, the EGR ratio can be freely set. That is, appropriate EGR control can be performed over the entire operation range of the diesel engine 1.

The auxiliary combustion chamber 1 of the diesel engine 1
3 is provided with an injection nozzle 11 for injecting fuel. This fuel injection nozzle 11 is connected to a fuel injection pump 14. The fuel injection pump 14 is driven based on the rotation of the output shaft 23 of the diesel engine 1 and pressurizes and supplies fuel to the injection nozzle 11. Also,
The fuel injection pump 14 includes a timer control valve 15 and a spill valve 16 for adjusting the injection timing and injection amount of the fuel injected from the injection nozzle 11. The operations of the timer control valve 15 and the spill valve 16 are also controlled by the ECU 19.

A rotor (not shown) that rotates in synchronization with the rotation of the output shaft of the diesel engine 1 is provided in the fuel injection pump 14, and a protrusion formed on the outer peripheral surface of the rotor is detected. A rotation speed sensor 17 comprising an electromagnetic pickup for outputting a pulse signal corresponding to the rotation speed is provided. This rotation speed sensor 17
Is taken into the ECU 19 as a signal contributing to the calculation of the rotational speed of the diesel engine 1.

The ECU 19 also stores accelerator opening information (accelerator information) detected by the accelerator opening sensor 18 such as atmospheric pressure information detected by the pressure sensor 6 and intake air temperature information detected by the intake air temperature sensor 78. Pedal depression information) and IG (ignition)
ON / OFF information of switch 20, starter switch 21
, The cooling water temperature information detected by the water temperature sensor 77, the output voltage information of the battery 22 that supplies power to various electric devices including the ECU 19 and the step motor 40, and the like. ing.

Next, the details of the drive mechanism 5 for opening and closing the intake throttle valve 4 will be described with reference to FIGS.
2 is a side sectional structure of the intake throttle valve 4 and its driving mechanism 5, FIG. 3 is a front view of the driving mechanism 5, and FIG. 4 is a driven gear 29 provided in the driving mechanism 5 and its driven gear 29. 3 shows a partial cross-sectional structure of a peripheral portion.

As shown in FIG. 2, the intake throttle valve 4 for making the opening area of the intake passage 2 variable and adjusting the amount of intake air flowing through the passage 2 is rotatable integrally with a valve shaft 26. Fixed. The valve shaft 26 is rotatably supported by a throttle body 25 connected to the intake passage 2. One end (the upper end in FIG. 2) of the valve shaft 26 is connected to the throttle body 25 via a return spring 27. And, the valve shaft 26 and the intake throttle valve 4
Is biased in a direction to open the intake throttle valve 4 by the biasing force of the return spring 27.

On the other hand, a driven gear 29 provided in a gear box 28 mounted on the throttle body 25 is attached to the other end (the lower end in FIG. 2) of the valve shaft 26 so as to be integrally rotatable. The driven gear 29 is meshed with a second intermediate gear 37 rotatably supported by a support shaft 35 provided in the gear box 28. Further, a first intermediate gear 36 that rotates integrally with the second intermediate gear 37 is attached to the support shaft 35. This first intermediate gear 3
Reference numeral 6 meshes with a drive gear 38 attached to the output shaft 41 of a step motor 40 mounted on the gear box 28 so as to be integrally rotatable. That is, the rotation of the output shaft 41 driven by the step motor 40 is transmitted to the valve shaft 26 via the driving gear 38, the first intermediate gear 36, the second intermediate gear 37, and the driven gear 29. The rotation of the valve shaft 26 drives the intake throttle valve 4 to open and close.

As shown in FIG. 3, the valve shaft 26 has a lever 3 having two arms 32a and 32b.
2 is rotatably mounted. This lever 32 is connected to the driven gear 29 via a relief spring 31. The lever 32 is connected to the relief spring 3
The driven gear 29 is urged in the counterclockwise direction in FIG. One of the arms 32b provided on the lever 32 is bent in an L-shape and extends toward the driven gear 29. The distal end of the arm 32b is engaged in a groove 30 formed in the driven gear 29, as shown in FIG. The lever 32 is relatively rotatable with respect to the driven gear 29 by the gap between the groove 30 and the tip of the arm 32b. However, usually, the tip of the arm portion 32b is
Due to the urging force of 1, the groove 30 is in contact with the side wall on the counterclockwise direction centering on the valve shaft 26. In this state, the driven gear 29 and the lever 32 are integrally rotated.

At the tip of the other arm 32a provided on the lever 32, a pressing portion 33 is provided which can abut on a fully open switch 39 provided in the gear box 28. The pressing portion 33 is in contact with the full-open switch 39 at the full-open position of the intake throttle valve 4, and can turn on the full-open switch 39. Note that, in the present embodiment, the intake throttle valve 4 is rotatable further in the opening side than the fully open position. Here, the fully open position refers to the position of the intake throttle valve 4 when the opening area of the intake passage 2 is maximized. Then, when the intake throttle valve 4 is further driven in the opening direction from the fully opened position, further opening drive is eventually restricted by a stopper (not shown). Hereinafter, the position of the intake throttle valve 4 at this time is referred to as a maximum opening position.

Further, a not-shown fully closed stopper is provided on the shaft portion opposite to the gear box 28. The fully closed stopper comes into contact with the stopper at a position where the intake throttle valve 4 is in the fully closed position.
Is restricted in the closing direction. Here, the fully closed position means the position of the intake throttle valve 4 when the opening area of the intake passage 2 is minimum, that is, 0. However, at this time, the driven gear 29 can rotate further in the closing direction than the fully closed position. When the driven gear 29 further rotates in the closing direction from the position where the rotation of the lever 32 is restricted by the contact of the stopper, the driven gear 29 is urged in the opening direction by the urging force of the relief spring 31. Will be done.

Next, an electric circuit configuration showing a control system of the diesel engine 1 will be described with reference to a block diagram shown in FIG. The ECU 19 reads out various control programs for controlling the fuel injection amount, the fuel injection timing, the EGR control, the intake air amount, etc. of the diesel engine 1 and maps for calculating values corresponding to various conditions. A dedicated memory (ROM) 61 is provided. Also, ECU
Reference numeral 19 denotes a central processing unit (CPU) 60 for executing arithmetic processing based on a program stored in the ROM 61.
And a random access memory (RAM) 62 for temporarily storing the result of calculation by the CPU 60 and data input from each sensor and the like.
R to maintain the power supply even when the power supply is cut off
AM63 and the like. These CPU 60 and ROM 6
1, a RAM 62 and a backup RAM 63 are connected to a bus 6
4 and an external input circuit 6
6 and an external output circuit 67.

On the other hand, in the ECU 19, input signals from the pressure sensor 6, the accelerator opening sensor 18, the water temperature sensor 77, and the intake air temperature sensor 78 are temporarily stored in a buffer 69. The input signals stored in each buffer 69 are sequentially selected by the multiplexer 68 based on the instruction of the CPU 60, converted into digital signals by the A / D converter 65, and sent to the external input circuit 66. The pulse-like input signal from the rotation speed sensor 17 is sent to the external input circuit 66 after being binarized by the waveform shaping circuit 71. Furthermore, IG switch 2
0, the state of the starter switch 21 and the state of the fully open switch 39 are also transmitted as on / off information of those switches.
The IG switch 20 is a switch for controlling start / stop of the engine, and is turned on when the engine is started and turned off when the engine is stopped. The starter switch 21 is a switch for driving a starter motor for starting the engine, and is turned on when the starter motor rotates,
It turns off when stopped.

Further, a part of the voltage supplied from the battery 22 is also supplied to the external input circuit 66 via the A / D converter 65.
It is taken in. Thus, the ECU 19 knows the voltage VB of the battery 22 supplied to the step motor 40 and the like.

On the other hand, an external output circuit 67 of the ECU 19 includes a drive circuit 72 of the step motor 40 and the EG
A drive circuit 73 of the actuator 10 for opening and closing the R control valve 9, a drive circuit 74 of the timer control valve 15 of the fuel injection pump 14, and the fuel injection pump 1
The drive circuit 75 of the spill valve 16 is connected. A command signal is sent to each of the drive circuits 72 to 75 based on the calculation result of the CPU 60. Then, each drive circuit 72
75 drive the step motor 40, the actuator 10, the timer control valve 15, and the spill valve 16 based on the command signal.

Next, the configuration of the step motor 40 and its control mode will be described with reference to FIGS. FIG. 6 shows a plan sectional structure of the step motor 40, and FIG.
2 shows a cross-sectional side structure of the motor 40. As shown in these figures, the step motor 40 is roughly composed of a rotor 42 that can rotate integrally with the output shaft 41, and two stator cups provided to surround the rotor 42, that is, A It comprises a phase stator cup 44 and a B-phase stator cup 45. A permanent magnet 43 is provided on the outer periphery of the rotor 42 so as to be integrally rotatable. This permanent magnet 4
3 shows the stepping motor 40 shown in FIGS.
As shown in the schematic cross-sectional view, N poles and S poles of magnetic poles are alternately formed at predetermined angular intervals.

On the other hand, as shown in FIGS. 6 and 7, the A-phase stator cup 44 and the B-phase stator cup 45 have a ring shape, and the rotor 42 is rotatable in a hollow portion thereof. Is housed. These stator cups 44 and 45
Inside, two sets of coils are provided, that is, an Ap phase coil 46 and an An phase coil 47, or a Bp phase coil 48 and a Bn phase coil 49. These coils 46 to 49 are wound in the same direction.

As shown in FIGS. 8A and 8B, in the stator cups 44 and 45, the inner periphery of the hollow portion in which the rotor 42 is housed, as shown in FIGS. The upper teeth 50 and the lower teeth 51 (A-phase stator cup 44) or the upper teeth 52 at the same predetermined angular intervals as the magnetic poles of the magnet 43.
And lower teeth 53 (B-phase stator cup 45) are formed alternately. These upper teeth 50 and 52 and lower teeth 51 and 53
Are excited when a voltage is applied to the coils 46 to 49. Note that the teeth 50 and 51 provided on the A-phase stator cup 44 and the teeth 52 and 53 provided on the B-phase stator cup 45 are shifted by half of the predetermined angle, that is, by half a tooth. Position.

Next, the electric circuit configuration of the step motor 40 and its drive circuit 72 will be described with reference to FIG.
9A and 9B, the stepping motor 40
The relationship between the outer peripheral portion of the rotor 42 and the inner peripheral portions of the stator cups 44 and 45 is schematically shown in a form developed in a plane. In FIG. 9, the electric circuit configuration is also schematically shown in a simplified manner in order to easily explain the function of the drive circuit 72.

Ap provided in the A-phase stator cup 44
A voltage is applied to the phase coil 46 and the An phase coil 47 by a DC power supply 58. The drive circuit 72 includes an Ap-phase coil switch 54 and an An-phase coil switch 5 for allowing or interrupting application of voltage to each of the coils 47 and 48.
5 are provided. By turning on each of the coil switches 54 and 55, a voltage is applied to each of the coils 47 and 48, and the upper teeth 50 and the lower teeth 51 are excited. Although the coils 47 and 48 are wound in the same direction as described above, the directions of the currents applied to the coils 47 and 48 are opposite as shown in FIGS. 9 (a) and 9 (b). It is configured so that Therefore, when the voltage is applied to the Ap-phase coil 46 and when the voltage is applied to the An-phase coil 47, the upper teeth 50 and the lower teeth 51 are excited to different poles. That is, when a voltage is applied to the Ap-phase coil 46, the upper teeth 50 are excited to the N pole and the lower teeth 51 are excited to the S pole. On the other hand, An
When a voltage is applied to the phase coil 47, the upper teeth 50
The lower teeth 51 are excited to the N pole.

A similar electric circuit configuration is employed in the B-phase stator cup 45, and the Bp-phase coil switch 56 and the Bn-phase coil switch 57 are selectively turned on and off by the respective coils 48 and 49. Is applied with a voltage. By applying a voltage to the Bp phase coil 48, the upper teeth 52 are excited to the N pole, and the lower teeth 53 are excited to the S pole.
Is excited to the S pole, and the lower teeth 53 are excited to the N pole.

Next, the operating principle of the step motor 40 driven by the drive circuit 72 will be described with reference to FIGS. The drive circuit 72 includes the CPU 6
0, and operates on one of the coils 46 and 47 of the A-phase stator cup 44 and one of the coils 48 and 49 of the B-phase stator cup 45 simultaneously or on each of the stator cups 44. , 45 to one of the coils 46 to 49. FIG. 10 shows an energization state of each of the coils 46 to 49 of the step motor 40.

The drive circuit 72 selectively switches among eight excitation phase modes 0 to 7 as shown in FIG. As apparent from FIG. 10, in the case of the odd-numbered excitation phase mode, the coils 46, 47 and 48, 4 of the stator cups 44, 45 are provided.
A voltage is applied to each of the coils 9 at a time, and in the case of an even number, a voltage is applied to only one of the coils 46 to 49.

FIG. 9A shows an embodiment of the drive circuit 72 and the step motor 40 in the excitation phase mode 1 (the value of the lower 3 bits of elstep = 1) shown in FIG. At this time, the drive circuit 72 closes the Ap-phase coil switch 54 and the Bp-phase coil switch 56, and applies a voltage to the Ap-phase coil 46 and the Bp-phase coil 48. By applying a voltage to these coils 46 and 48, the upper teeth 50 of the A-phase stator cup 44 become the N pole, the lower teeth 51 become the S pole, and similarly, the upper teeth 52 of the B phase stator cup 45 become the north pole. The lower teeth 53 are excited to the N pole and the lower teeth 53 are excited to the S pole. At this time, the S-pole of the permanent magnet 43 of the rotor 42 has the upper teeth 50 of the A-phase stator cup 44 and the upper teeth 52 of the B-phase stator cup 45 excited to the N-pole.
At the center of the upper teeth 50 and 52. Similarly, the N-pole of the permanent magnet 43 of the rotor 42 is connected to the A-phase stator cup 44 excited to the S-pole.
The lower teeth 51 and the lower teeth 53 of the B-phase stator cup 45 are attracted to the lower teeth 51 and 53, and are drawn to an intermediate position between the lower teeth 51 and 53. Thus, the rotor 42 has the S
The pole is rotated so that the pole is located at a position between the upper teeth 50 and 52 and the N pole of the permanent magnet 43 is also located at a position between the lower teeth 51 and 53.

Thereafter, when the excitation phase mode is changed from mode 1 to mode 3, as shown in FIG. 10, the driving circuit 72 switches so that a voltage is applied to the An phase coil 47 and the Bp phase coil 48. The settings are made. FIG. 9B shows an aspect of the drive circuit 72 and the step motor 40 in the excitation phase mode 3 (the value of the lower 3 bits of elstep = 3). At this time, the upper teeth 50 of the A-phase stator cup 44 are excited to the S pole, the lower teeth 51 are excited to the N pole, the upper teeth 52 of the B phase stator cup 45 are excited to the N pole, and the lower teeth 53 are excited to the S pole. Become so. Thus, the S pole of the permanent magnet 43 of the rotor 42 becomes the lower teeth 51 of the A-phase stator cup 44 excited to the N pole.
And the N-pole of the permanent magnet 43 is similarly attracted to the intermediate position between the upper teeth 52 of the B-phase stator cup 45 and the upper teeth 50 of the A-phase stator cup 44 and the B-phase stator. The suction is performed at a position intermediate the lower teeth 53 of the cup 45. Thus, the rotor 42 is rotated rightward by half a tooth in FIG. 9, and the output shaft 41 is rotated clockwise by half the predetermined angle. In the present embodiment, the output shaft 41
When the (rotor 42) rotates rightward in FIG. 9, the intake throttle valve 4 is closed, and when the rotor 42 rotates leftward, the valve 4 is opened.

As described above, the drive circuit 72 switches the excitation phase mode so that the output shaft 41 of the step motor 40 is switched.
Specifically, by switching the excitation phase mode in descending order, the intake throttle valve 4 is opened, and by switching the excitation phase mode in ascending order, the intake throttle valve 4 is closed. The output shaft 41 is rotated.

In the control device of the present embodiment, when the step motor 40 is rotated, the two excitation methods are used properly. That is, the excitation phase mode is changed one by one, specifically, the excitation phase mode is changed from mode 0 → mode 1 →
Mode 2... Or Mode 2 → Mode 1 → Mode 0... And a mode in which a mode in which only one coil is excited and a mode in which two coils are simultaneously excited are alternately repeated (hereinafter referred to as “1- Two-phase excitation method) and two excitation phase modes so that the excitation phase mode always has an odd number. More specifically, the excitation phase mode is changed from mode 1 to mode 3 to mode 5 or mode 5 to mode. The mode is switched from mode 3 to mode 1... And is rotated using only the mode in which two coils are simultaneously excited (hereinafter referred to as “2
Phase excitation method "). 1-
In the case of the two-phase excitation method, the rotation angle of the rotor 42 of the step motor 40 per switching of the excitation phase mode can be set finely, and the opening degree of the intake throttle valve 4 can be finely controlled. On the other hand, in the case of the two-phase excitation method, the rotation angle of the rotor 42 per switching of the excitation phase mode can be increased, and the opening and closing speed of the intake throttle valve 4 can be increased. In this way, by using the two excitation methods properly according to the situation, it is possible to achieve both improvement in accuracy and improvement in followability in controlling the opening degree of the intake throttle valve 4.

In the present embodiment, the opening angle of the intake throttle valve 4 is controlled by defining the rotation angle per switching of the excitation phase mode in the 1-2-phase excitation method as one step. Therefore, in the case of the two-phase excitation method, the motor is rotated by two steps each time the excitation phase mode is switched.

Next, the stepping motor 40 of the present embodiment
The specific drive control mode will be described in detail with reference to FIGS. In the present embodiment, the operation amount of the intake throttle valve 4 is grasped from the number of steps of the driven step motor 40, and the opening degree control of the intake throttle valve 4 is performed based thereon. When performing such control, it is necessary to grasp the correspondence between the step position of the step motor 40 and the actual opening degree of the intake throttle valve 4. However, due to step-out of the step motor 40 or interruption of power supply during stoppage of the engine 1, it is sometimes impossible to grasp these measures. Therefore, in the present embodiment, prior to the control of the opening degree of the intake throttle valve 4, an initialization process for determining the above correspondence is executed.

First, such initialization processing will be described. When the initialization process is started, the CPU 60
First, the on / off state of the full-open switch 39 is confirmed. Then, the CPU 60 drives the step motor 40 in the direction in which the fully open switch 39 is switched, and sets the step position at the time when the switch 39 is switched as the reference position. The reference step position is set at the step position of the step motor 40 where the ON / OFF state of the full-open switch 39 is switched, and the current step elsac
This is performed by storing the value of t as “0” and the mode value of the excitation phase mode at that time as an offset value elsof. This current step elsact is performed by the intake throttle valve 4
Is subtracted when the valve is opened, and is added when the valve is closed. Thus the current step elsact
Is increased or decreased with the opening and closing of the intake throttle valve 4, the opening degree of the intake throttle valve 4 can be grasped from this value.
In addition, the opening degree control of the intake throttle valve 4 includes an excitation phase corresponding step elst which is a sum of the current step elsact thus set and the stored offset value elsof.
ep is used. This excitation phase corresponding step elste
The value of the lower 3 bits of p (0 to 7) is
This corresponds to the excitation phase mode value of the step motor 40 at lsact (FIG. 10).

Next, the drive control of the step motor 40 during the opening degree control of the intake throttle valve 4, which is executed after the above-described initialization processing is completed, will be described. In controlling the drive of the step motor 40, the CPU 60 first confirms the magnitude relationship between the current step elsact and the target step elstrg, and determines the drive direction of the step motor 40. When the current step elsact is larger, the step motor 40 is driven to the valve opening side to set the target step e
If lstrg is larger, drive to the valve closing side. If the current step elsact matches the target step elstrg, the intake throttle valve 4
Since the target opening degree has already been attained, the excitation phase of the step motor 40 is held as it is, and the intake throttle valve 4
To maintain the current opening.

The CPU 60 also determines the driving method of the step motor 40. As described above, the stepping motor 40 according to the present embodiment performs two types of driving, that is, a 1-2-phase excitation method in which one step is driven for each excitation phase switching and a two-phase excitation method in which two steps are driven. It can be carried out. In the present embodiment, the step motor 40 is normally driven by the two-phase excitation method,
Is currently one-phase excited and the target step elst
Only when the difference between rg and the current step elsact is “1” step, driving is performed by the 1-2 phase excitation method.

After setting the driving direction and the driving method of the step motor 40 in this way, the CPU 60 changes the current step elsact. In the case of driving in the valve opening direction, "1" or "2" is subtracted from the current step elsact depending on the driving method. When driving in the valve closing direction, "1" or "2" is similarly added to the current step elsact.

As described above, the current step els
act is brought close to the target step elstrg, and the drive of the step motor 40 is controlled so as to match the target step elstrg.
Is controlled so that the target opening is set as the target opening.

Next, the processing of the target opening calculation routine for setting the target step elstrg which is the drive target value of the step motor 40 will be described with reference to FIG.
It should be noted that the processing of this routine is executed as a periodic interruption processing every predetermined time.

Upon shifting to this routine, the CPU 60
First, as processing S100, it is determined whether or not the IG (ignition) switch 20 is off. If the ignition switch 20 is turned off, that is, if a request to stop the engine 1 has been issued, the processing of the CPU 60 proceeds to step S102.
Move to In this process S102, the CPU 60
The target step elstrg is set to a value corresponding to the fully closed position of the intake throttle valve 4. Thereafter, the CPU 60 temporarily ends the processing of this routine.

When the IG switch 20 is turned off, it is necessary to stop the diesel engine 1 immediately. In this embodiment, in such a case, the intake throttle valve 4 is fully closed,
In order to shut off the supply of the intake air to the engine 1 and quickly stop the engine 1, the target step elstrg is set to the above value, and the intake throttle valve 4 is fully closed.

On the other hand, when the IG switch 20 is on, C
In step S101, the PU 60 determines whether an abnormality has occurred in the fuel injection system such as the fuel injection pump 14 and the injection nozzle 11. If an abnormality occurs in the fuel injection system, the diesel engine 1 can no longer be controlled, so it is necessary to stop the engine 1 immediately. Therefore, even when an abnormality has occurred in the fuel injection system, the CPU 60 shifts to the process of step S102, and executes the process in the target step elstrg.
Is set to a value corresponding to the fully closed position of the intake throttle valve 4 so that the engine 1 is stopped immediately. Then, the CPU 60 temporarily ends the processing of this routine.

If no abnormality has occurred in the fuel injection system, the CPU 60 determines in step S103 whether the battery voltage VB is higher than 10V. When the battery voltage VB is equal to or lower than 10 V, the drive voltage of the step motor 40 becomes insufficient and the output decreases. In such a case, the drive torque at the time of driving the intake throttle valve 4 is insufficient, so that the step motor 40 is likely to lose synchronism. Therefore, here, the battery voltage VB is 10 V or less (N
If it is determined to be O), the CPU 60 proceeds to step S10.
In step 4, after the target step elstrg is set to “+9” steps, the processing of this routine is temporarily terminated. Note that this value “+9” steps is the number of steps of the step motor 40 that is outside the range in which the confirmation processing described later is executed and that can position the intake throttle valve 4 near the fully open position. At this time, as long as the normal state is maintained, the full-open switch 39 is not turned on. As described above, when the battery voltage VB is equal to or lower than 10 V, by fixing the target step elstrg to the above value, it is possible to position the intake throttle valve 4 near the fully open position and to drive the step motor 40 further. They are banned.

As described above, the diesel engine 1
If the required amount of intake air is secured by the mechanism,
Even if the intake air amount is further increased, the operation can be continued without any trouble. Therefore, the battery voltage V
When B decreases, the intake throttle valve 4 is retracted to the vicinity of the fully open position, and a target step el in which a sufficient intake air amount can be secured.
By setting strg, the operation of the diesel engine 1 can be continued without any trouble.

On the other hand, if it is determined in the previous step S103 that the battery voltage VB is higher than 10 V,
In step S105, the PU 60 determines the target step elstr based on the two-dimensional map illustrated in FIG. 12 based on the correspondence between the engine speed NE and the fuel injection amount command value Qfinc.
Calculate g. The target step e calculated here
lstrg is determined by the atmospheric pressure detected by the pressure sensor 6, the cooling water temperature detected by the water temperature sensor 77, and the atmospheric temperature sensor 78 so that an appropriate intake air amount according to the operating conditions of the diesel engine 1 is secured. The value is corrected according to the detected atmospheric temperature or the like.

After setting the target step elstrg in this way, the CPU 60 determines whether or not the target step elstrg is less than the above-mentioned "+9" step in the process of step S106. If it is determined in this processing S106 that the target step elstrg is equal to or greater than the above-mentioned “+9” step, the CPU 60 turns off the confirmation processing completion flag exchkend in processing S107, and then temporarily ends the processing of this routine.

In this embodiment, the target step e
When lstrg is less than the above “+9” step,
It is assumed that a full-open command to fully open the intake throttle valve 4 has been issued. Then, every time the full opening command is issued, a confirmation process is executed to confirm that the opening degree of the intake throttle valve 4 on the control grasped from the number of steps of the step motor 40 matches the actual opening degree. ing. The confirmation processing completion flag e
xchkend is a confirmation processing request flag exg described later.
Used together with lchk to determine the execution of the confirmation process. The confirmation processing completion flag exchkend is turned on when the confirmation processing is completed, and the target step els
It is turned off when trg becomes "+9" steps or more.

If it is determined in step S106 that the target step elstrg is smaller than the above-mentioned "+9" step, the CPU 60 determines in step S108 whether or not the confirmation processing completion flag exchkend is on. judge. This confirmation processing completion flag exch
Even if “kend” is on, the target step “elstrg”
Is a “+9” step. In this way, if the confirmation processing has already been completed at the time of this output of the full-open command, the target step elstrg is set to “+” until the full-open command is released.
It is held in 9 "steps. This" +9 "
As described above, the number of steps referred to as steps corresponds to the position near the fully open position of the intake throttle valve 4 and at which the confirmation process is not performed.

On the other hand, the confirmation processing completion flag exchken
When d is off, the CPU 60 determines in step S110
The target step elstrg is set to “−2” steps, and the confirmation processing request flag exglchk is turned on, and the processing of this routine is temporarily terminated. Here, the value of −2 of this target step elstrg is the fully open switch 39.
When the ON / OFF state of the switch 39 is checked, the opening of the intake throttle valve 4 is set to an opening position further on the valve opening side than the opening position at which the switch 39 switches from OFF to ON, so that the switch 39 is surely set. The step position is switched to ON, and is set so as not to cause an erroneous determination due to chattering of the fully open switch 39 caused by vibration of the diesel engine 1 or the like.

Next, the control opening degree of the intake throttle valve 4 ascertained from the current step elsact of the step motor 40 and the actual opening of the intake throttle valve 4 ascertained by switching the full open switch 39 on and off. The processing of the confirmation processing routine for confirming the correspondence with the degree will be described based on the flowchart of the routine shown in FIG.

The process of this routine is started as an interrupt process each time the stepping motor 40 enters the excitation switching state. The cycle of the excitation switching state is as follows.
It is calculated by the CPU 60 based on the driving state of the step motor 40, the operating state of the diesel engine 1, and the like. The opening / closing speed of the intake throttle valve 4 is adjusted by changing the cycle of the excitation switching state.

When the processing shifts to the processing of this routine, first, in processing S200, the CPU 60 determines that the confirmation request flag exglchk is on and the current step el
Check whether sact is less than “+7” steps. Note that when the confirmation request flag exglchk is on, the target step elstrg for the step motor 40 is set to "-2" as described above. In this process S200, if both conditions are satisfied, the CPU 60 executes the process S2
Move to 01. In this process S201, the CPU 6
0 indicates whether or not the current step elsact is a “+6” step, that is, whether or not the current opening position of the intake throttle valve 4 is at the opening position on the valve closing side by 6 steps from the fully open position. judge.

If the determination condition of step S201 is satisfied, the process of CPU 60 shifts to step S202. In this process S202, the CPU 60 operates the full-open switch 39.
Check the on / off status of. At this time, if the full-open switch 39 is off, the processing of the CPU 60 temporarily shifts to the drive control routine of the step motor 40 described above.
At this time, when the fully open switch 39 is checked, the CPU 60
Makes the change cycle of the exciting phase described above slow. By delaying the change cycle of the excitation phase in this way, a time is secured until the damping of the step motor 40 converges, and the switch state can be surely confirmed.

If the normal operation is being performed, the intake throttle valve 4 at this time is moved from the fully open position to the position of the step motor 40 by 6.
It should be located on the valve closing side by an amount corresponding to the step, and the fully open switch 39 should be off. Conversely, if the fully open switch 39 is turned on in the process S202, the correspondence between the step position of the step motor 40 and the opening position of the intake throttle valve 4 does not match. In this case, it is determined that some abnormality has occurred, and the CPU 60 shifts to the process of step S203.
Execute the processing when an error occurs.

As an abnormal process, the CPU 60 executes the above-described initialization process again, and sets the reference step position again. If the cause of the abnormality is the step-out of the step motor 40, the correspondence between the step position of the step motor 40 and the opening position of the intake throttle valve 4 is again matched by resetting the reference step position. And the opening degree control of the intake throttle valve 4 can be executed again. If this setting process is not performed normally, it is determined that an abnormality that cannot be easily recovered has occurred in the control system of the intake throttle valve 4, such as a failure of the full-open switch 39 or a fixation of the step motor 40 and the intake throttle valve 4. Is done. In this case, the CPU 60 holds the excitation phase of the step motor 40 in the current state to fix the intake throttle valve 4 at the current opening position, thereafter stops the opening control of the same, and further stops the EGR.
Control also stops. Further, measures such as limiting the fuel injection amount are taken so that the operation of the diesel engine 1 can be maintained.

Further, in the present embodiment, even if the opening degree control of the intake throttle valve 4 can be restored by the above-described abnormality processing, the abnormality determination is performed at least a predetermined number of times after the present start of the diesel engine 1. Is performed, it is also determined that an abnormality has occurred in the control system, and measures such as stopping the opening control of the intake throttle valve 4 are taken.

On the other hand, when the determination condition of the processing S201 is not satisfied, that is, when the current step elsact is “
If it is not more than +5 "steps, the CPU 60 proceeds to step S2.
Move to 04. In this process S204, the CPU 60
Means that the current step elsact is the target step els
It is determined whether or not the “-2” step matches trg. Here, the current step elsact is "-2".
If the step has not been reached, the process temporarily shifts to the drive control routine of the step motor 40 described above. On the other hand, if the current step elsact has reached the “−2” step, the CPU 60 checks the on / off state of the full-open switch 39 in step S205. At this time, if the normal operation is performed, the intake throttle valve 4 should be located further on the valve opening side than the fully open position, and the fully open switch 39 should be on. Therefore, when the fully open switch 39 is turned off in this process S205,
The CPU 60 shifts to the aforementioned processing S203, and executes the same abnormal processing as before.

If the fully open switch 39 is turned on in step S205, it can be confirmed that the correspondence between the step position of the step motor 40 and the opening position of the intake throttle valve 4 is normal. At this time, CPU
60 proceeds to step S206, where the confirmation completion flag ex
After turning on chkend and turning off the confirmation request flag exglchk, the process proceeds to the drive control routine of the step motor 40. As described above, the confirmation completion flag exch
Kend is turned off when the full-open command is not issued, and turned on when the confirmation processing is completed. By setting the confirmation completion flag exchkend in this manner, the confirmation processing is performed only once each time the fully open command is issued.

On the other hand, if the confirmation request flag exglchk is off or the current step elsact is equal to or greater than the “+7” step in the processing S200, the CPU 60 proceeds to the processing S207. In this process S207, the CPU 60 determines the current step el.
It is determined whether or not sact is equal to or more than “+7” steps. Then, the current step Elsact is “+7”
If it is less than the step, that is, if the confirmation request flag exglchk has already been turned off, the process directly proceeds to the drive control routine of the step motor 40. If the confirmation request flag exglchk is equal to or more than the "+7" step, the process proceeds to step S208. To confirm the ON / OFF state of the fully open switch 39. At this time, the CPU 60 also increases the confirmation accuracy by delaying the change period of the excitation phase. If the normal operation is performed, the intake throttle valve 4 at this time should be located closer to the valve closing side than the switching position of the full open switch 39, and the full open switch 39 should be off.
Therefore, the fully open switch 3
If 9 is on, it is considered that some abnormality has occurred. In this case, the CPU 60 shifts to the process S203 and executes the above-mentioned abnormal process. On the other hand, the processing S
If a negative (NO) determination is made in 208, that is, if it is determined that the current step elsact is equal to or greater than the “+7” step and that the full-open switch 39 is off, the normal state is maintained. If so, the process proceeds to the drive control routine of the step motor 40 described above.

As described above, according to the present embodiment, the following effects can be obtained. (1) When the battery voltage drops and the voltage applied to the step motor 40 becomes insufficient, the target opening of the intake throttle valve 4 is held and the driving of the step motor 40 is prohibited, so that Step-out can be greatly suppressed.

(2) By setting the target opening of the intake throttle valve 4 at that time near the full opening on the condition that the ignition switch 21 is on, at least the amount required for the diesel engine 1 is obtained. The intake throttle valve 4 can be retracted to a position where the above intake air can be supplied, and the subsequent operation of the diesel engine 1 can be performed without any trouble.

(3) By setting the target opening at that time outside the opening range in which the confirmation processing is executed, it is possible to prevent erroneous determination in the confirmation processing. Further, since the driving of the step motor 40 in the confirmation processing can be prohibited, the occurrence of the step-out of the motor 40 can be further suppressed.

(4) When the ignition switch 21 is turned off or when an abnormality occurs in the fuel injection system or the like, the target opening of the intake throttle valve 4 is set as a value corresponding to the fully closed position. By giving priority to the process of retracting the intake throttle valve 4 to the fully closed position, the intake air is shut off and the diesel engine 1 can be stopped quickly.

(5) When the intake throttle valve 4 is stopped at the retracted position, the excitation state of the step motor 40 is maintained so that the intake pulsation and the vibration of the intake throttle valve 4 due to the vibration of the diesel engine 1 are prevented. Can be avoided. As a result, the intake throttle valve 4 and the full-open switch 3 due to unnecessary vibration
9 can be prevented from deteriorating.

Note that the embodiment of the present invention may be modified as follows. The opening position at which the intake throttle valve 4 is retracted when the ignition switch 21 is turned off or when an abnormality occurs in the fuel injection system or the like is not limited to the fully closed position, and may be in the vicinity thereof.

The full open switch 39 is not limited to the one provided in the gear box 28 of the drive mechanism 5 as in the above embodiment, but is provided in the throttle body 25 in which the intake throttle valve 4 is provided. A type in which the opening position of the throttle valve 4 is directly confirmed, or a type provided outside the throttle body 25 and in which the opening position is confirmed based on the rotation angle of the valve shaft 26 may be used. . In addition, the position of the opening of the intake throttle valve 4 was confirmed, and to that effect,
It is not necessary to use a switch as long as the device can give an instruction.

A control structure that does not execute the above confirmation process may be used. In the present embodiment, the value of the battery voltage VB (= 10
V) and the like are arbitrary, and these values may be set as boundary conditions under which the drive voltage of the step motor 40 becomes insufficient and the output decreases.

In the above-described embodiment, the intake throttle valve of the diesel engine has been described. However, when the drive power supplied to the step motor is insufficient, the control valve is held at a predetermined value while maintaining the drive target value of the step motor. The control for retracting to the opening degree can be applied to a control valve driven by another step motor, for example, an EGR valve or a throttle valve of a gasoline engine.

[0088]

According to the method of the first aspect and the configuration of the sixth aspect, the drive of the step motor is limited when the drive voltage is reduced, and the drive is finally prohibited by finally restricting the drive.
It is possible to preferably suppress the occurrence of step-out or the like of the motor.

The method according to claim 2 and the method according to claim 7
According to the configuration described in the above, when the drive voltage of the step motor is lowered, the opening target value of the step motor is set as the retreat position equivalent value, and the drive amount of the step motor is reduced as much as possible, so Generation can be suppressed appropriately.

The method according to claim 3 and the method according to claim 8
According to the configuration described in the above, when the drive voltage of the step motor decreases, the intake throttle valve is retracted to the full open position or in the vicinity thereof, so that the intake air amount more than necessary is secured in the combustion chamber of the diesel engine. As a result, the operation of the diesel engine can be suitably maintained.

Furthermore, the method according to claim 4 and the method according to claim 9
According to the configuration described in the above, when a system abnormality such as a fuel injection system of the diesel engine occurs, or when the ignition switch is turned off, the diesel engine is retracted to or near the fully closed position of the intake throttle valve. The intake air supplied to the combustion chamber of the engine is shut off or greatly reduced, and the engine can be stopped immediately.

Furthermore, the method according to claim 5 and the method according to claim 1
According to the configuration described in No. 0, when the drive voltage of the step motor is lowered or when the system of the engine is abnormal, the confirmation process is not executed, so that the drive of the step motor accompanying the confirmation process is prohibited to remove the motor. It is possible to suppress the occurrence of tonality and the like, and prevent erroneous determination at the time of confirmation.

[Brief description of the drawings]

FIG. 1 is a schematic diagram showing a configuration of a diesel engine provided with an intake throttle valve control device according to an embodiment of the present invention.

FIG. 2 is a sectional view showing a side sectional structure of an intake throttle valve and a drive mechanism thereof.

FIG. 3 is a front view showing a front structure of a drive mechanism of the intake throttle valve.

FIG. 4 is a partial sectional view of a drive mechanism of the intake throttle valve.

FIG. 5 is a block diagram showing an electrical configuration of the diesel engine.

FIG. 6 is a sectional view showing a planar sectional structure of a step motor.

FIG. 7 is a sectional view showing a side sectional structure of the step motor.

FIG. 8 is a schematic diagram showing a schematic configuration of the step motor.

FIG. 9 is a schematic diagram showing an electric circuit configuration and a driving mode of the step motor.

FIG. 10 is a diagram showing a state of energization of each coil of the step motor.

FIG. 11 is a flowchart showing a processing procedure of a target opening degree calculation routine.

FIG. 12 is a graph showing a relationship between a fuel injection amount and an engine speed of a diesel engine and a target step of a step motor.

FIG. 13 is a flowchart showing a processing procedure of a step motor drive control routine.

[Explanation of symbols]

1 ... diesel engine, 2 ... intake passage, 4 ... intake throttle valve,
5: intake throttle valve driving mechanism, 6: intake pressure sensor, 7: exhaust passage, 8: EGR passage, 9: EGR control valve, 19: electronic control unit (ECU), 20: IG switch, 21: starter switch, 22 ... Battery, 26 ... Valve shaft, 29 ... Driven gear, 32 ... Lever, 33 ... Pressing part, 35 ... Support shaft, 3
6 First intermediate gear, 37 Second intermediate gear, 38 Drive gear, 39 Fully open switch, 40 Step motor, 41
... output shaft, 42 ... rotor, 43 ... permanent magnet, 44 ... A-phase stator cup, 45 ... B-phase stator cup, 46 ... Ap-phase coil, 47 ... An-phase coil, 48 ... Bp-phase coil, 4
9 Bn-phase coil, 60 CPU, 72 driving circuit.

[Procedure amendment]

[Submission date] July 14, 1999

[Procedure amendment 1]

[Document name to be amended] Statement

[Correction target item name] Claims

[Correction method] Change

[Correction contents]

[Claims]

[Procedure amendment 2]

[Document name to be amended] Statement

[Correction target item name] 0010

[Correction method] Change

[Correction contents]

[0010] The invention described in claim 4 is the invention according to claim 3.
In the control method of the step motor type valve device according to the above,
When opening and closing the intake throttle valve based on the step number control.
And a predetermined step position of the step motor and the class
Check the relationship with the opening of the throttle valve at the fully open position of the intake throttle valve.
Retreat position according to the state of the engine
Set the target value of the opening of the intake throttle valve to the equivalent value
Position phase near the fully open position of
The gist is to make this value .

[Procedure amendment 3]

[Document name to be amended] Statement

[Correction target item name] 0011

[Correction method] Change

[Correction contents]

The invention described in claim 5 is the third invention.
Or the control method of the step motor type valve device described in 4.
System failure or ignition
When the switch is off, the drive voltage of the step motor
Equivalent to the evacuation position according to the state of the engine,
The target value of the opening degree of the intake throttle valve is set to the value.
The gist is that it is at or near the position .

[Procedure amendment 4]

[Document name to be amended] Statement

[Correction target item name] 0015

[Correction method] Change

[Correction contents]

[0015] The invention according to claim 9 provides the invention according to claim 8.
In the control device of the step motor type valve device according to the above,
When opening and closing the intake throttle valve based on the step number control.
A predetermined step position of the step motor and the suction position.
The relationship with the opening degree of the throttle valve is determined at the fully open position of the throttle valve.
Means for performing a confirmation process, wherein the opening degree target value setting means is provided.
Is an intake throttle corresponding to a retract position corresponding to the engine state.
The opening target value of the intake throttle valve near the fully open position of the intake throttle valve and
The gist of the present invention is to set a value corresponding to a position at which the confirmation process is not performed .

[Procedure amendment 5]

[Document name to be amended] Statement

[Correction target item name] 0016

[Correction method] Change

[Correction contents]

Further, the invention described in claim 10 is the invention
10. The control device for a step motor type valve device according to 8 or 9.
In the above, the opening target value setting means may include a system for the engine.
If the system malfunctions or the ignition switch is off,
Regardless of the drive voltage of the step motor,
Open the intake throttle valve to a value corresponding to the evacuation position according to the engine state
Degree target value with the fully closed position of the intake throttle valve or its vicinity.
The gist of this is to do

[Procedure amendment 6]

[Document name to be amended] Statement

[Correction target item name] 0020

[Correction method] Change

[Correction contents]

Further, the method according to claim 4 and the method according to claim 9
According to the configuration described in (1), the drive voltage of the step motor decreases.
Confirmation process is performed at the time of
Doing so prevents the confirmation process from being performed.
Motor drive is prohibited to prevent step-out of the motor, etc.
Control and prevent misjudgment during confirmation.
I will be able to.

[Procedure amendment 7]

[Document name to be amended] Statement

[Correction target item name] 0021

[Correction method] Change

[Correction contents]

Furthermore, the method according to claim 5 and the method according to claim 1
According to the configuration described in Item 0, the fuel injection system of the diesel engine
When a system error such as
When the power switch is off, the drive
Despite the pressure, the target opening value of the intake throttle valve is in the fully closed position
Or near it, the combustion of the diesel engine
Cut off or significantly reduce the intake air supplied to the room
Will be able to do it. That is, immediately
To prevent step-out of the step motor, etc.
Control.

[Procedure amendment 8]

[Document name to be amended] Statement

[Correction target item name] 0091

[Correction method] Change

[Correction contents]

Furthermore, the method according to claim 4 and the method according to claim 9
According to the configuration described in (1), the drive voltage of the step motor decreases.
Confirmation process is performed at the time of
Doing so prevents the confirmation process from being performed.
Motor drive is prohibited to prevent step-out of the motor, etc.
Control and prevent misjudgment during confirmation.
I will be able to.

[Procedure amendment 9]

[Document name to be amended] Statement

[Correction target item name] 0092

[Correction method] Change

[Correction contents]

Furthermore, the method according to claim 5 and the method according to claim 1
According to the configuration described in Item 0, the fuel injection system of the diesel engine
When a system error such as
When the power switch is off,
Regardless of the dynamic voltage, set the intake throttle valve to the fully closed position or
Is evacuated to the vicinity, so that the combustion of the diesel engine
Shut off or significantly reduce the intake air supplied to the room
So that the organization can be shut down promptly.
Become.

Claims (10)

[Claims] 1. A control method of a step motor type valve device for opening and closing a valve based on a step number control based on a predetermined step position of a step motor drivingly connected to the valve, the method comprising: And controlling the valve opening target value to a fixed value when the drive voltage is equal to or lower than a predetermined voltage. 2. The intake throttle valve provided in an intake passage of a diesel engine, wherein the opening degree target of the intake throttle valve is set to a fixed value based on a drive voltage of the step motor being equal to or lower than a predetermined voltage. The method according to claim 1, wherein the value is a value corresponding to a retracted position corresponding to an engine state. 3. The step motor type valve device according to claim 2, wherein the target value of the opening degree of the intake throttle valve, which is a value corresponding to the retreat position according to the engine state, is set to a fully open position of the intake throttle valve or in the vicinity thereof. Control method. 4. When the system abnormality of the engine or the ignition switch is turned off, the target value of the opening degree of the intake throttle valve, which is a value corresponding to the retreat position according to the engine state, is set at or near the fully closed position of the intake throttle valve. Claim 2 or 3
3. The method for controlling a step motor valve device according to claim 1. 5. A process for confirming a relationship between a predetermined step position of the step motor and an opening degree of the class throttle valve at a fully open position of the intake throttle valve when opening and closing the intake throttle valve based on the step number control. Wherein the target value of the opening degree of the intake throttle valve, which is a value corresponding to the retreat position according to the engine state, is a value corresponding to a position near the fully open position of the intake throttle valve and at which the confirmation process is not executed. A method for controlling a step motor type valve device according to any one of claims 2 to 4. 6. A control device for a step motor type valve device for opening and closing said valve based on step number control based on a predetermined step position of a step motor which is drivingly connected to the valve device, comprising: A stepping motor, comprising: monitoring means for monitoring the voltage; and opening target setting means for setting the opening target value of the valve to a fixed value when the monitored driving voltage is equal to or lower than a predetermined voltage. A control device for a valve system. 7. The intake throttle valve provided in an intake passage of a diesel engine, wherein the opening target setting means sets the fixed opening target value of the intake throttle valve according to an engine state. 7. The control device for a step motor type valve device according to claim 6, wherein the value corresponds to the retracted position. 8. The opening target value setting means sets an opening target value of the intake throttle valve, which is a value corresponding to a retreat position corresponding to the engine operating state, to a fully open position of the intake throttle valve or a vicinity thereof. The control device for a step motor type valve device according to claim 7. 9. The opening target value setting means, when a system abnormality of the engine or an ignition switch is turned off, sets an opening target value of the intake throttle valve to a value corresponding to a retract position corresponding to the engine state. 9. The control device for a step motor type valve device according to claim 7, wherein the throttle valve is at a fully closed position or in the vicinity thereof. 10. The control device for a step motor type valve device according to claim 7, wherein when opening and closing the intake throttle valve based on the step number control, a predetermined step position of the step motor and the predetermined position of the step motor are determined. Means for confirming the relationship with the degree of opening of the intake throttle valve at the fully open position of the intake throttle valve, wherein the target opening degree setting means sets a value corresponding to a retreat position corresponding to the engine state. A control device for a step motor type valve device, wherein a target valve opening value is a value corresponding to a position near the fully open position of the intake throttle valve and at which the confirmation process is not executed.