JPH11294198A - Intake throttle valve control method and device for diesel engine - Google Patents

Abstract

PROBLEM TO BE SOLVED: To suitable control a step-motor type intake throttle valve in accordance with the engine condition, even in a state of the opening of the intake throttle valve not grasped, for instance, such as the initialization procedure is not executed, in controlling the step-motor type intake throttle valve. SOLUTION: An intake throttle valve 4 arranged in the intake passage 2 of a diesel engine 1 and open/close driven by a step motor 40 is provided with a full-open switch 39 with on-off condition changed over when the valve positions the full-open position. An electric control device 19 carries out the initialization procedure to take the correspondence between the actual opening of the intake throttle valve 4 grasped by the full-open switch 39 and the control opening grasped from the step position of the step motor 40. An electric control device 19 restricts the operating quantity of the intake throttle valve 4 to the quantity from the full-open position to the full-close position during upto the completion of initialization procedure, so that the intake throttle valve 4 is forcibly driven to a siding position in accordance with the engine condition.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a method and a device for controlling an intake throttle valve provided in an intake passage of a diesel engine and driven to be opened and closed by a step motor.

[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.

By the way, in order to control the opening of the intake throttle valve by using such a device, it is necessary that the step position of the step motor and the opening of the intake throttle valve always correspond. However, in such a valve device, the step position and the opening degree of the intake throttle valve correspond to the step position due to step-out of the step motor or interruption of the power supply to the step motor when the engine is stopped. Relationships may be disrupted. For this reason, in such a valve device, it is usually necessary to perform an initialization process for initializing the correspondence and correcting a deviation or the like.

[0005] Conventionally, as a control device for performing such initialization processing, for example, a device described in Japanese Patent Application Laid-Open No. 3-57852 is known. That is, in the device, a switch is provided for switching on and off at a predetermined opening of the intake throttle valve, and the step position of the step motor at the time when the switch is switched on and off is determined as a reference step. By setting the position, the correspondence between the opening degree of the intake throttle valve and the step position of the step motor is initialized.

[0006]

Such initialization is performed by:
It is desirable to perform it every time the engine is started in consideration of the case where the opening of the intake throttle valve is unintentionally changed when the power supply to the step motor is cut off. However, in the above-described conventional apparatus, even if the initialization is performed at the time of starting the engine, until the initialization process is completed, or if initialization cannot be performed for some reason, the intake throttle valve is not used. And the step position of the step motor cannot be matched, and it is unavoidable that the intake throttle valve is driven to an unintended opening degree.

[0007] The present invention has been made in view of such circumstances, and its object is to provide an engine state even when the opening degree of the intake throttle valve cannot be grasped, such as when the initialization processing has not been completed. It is an object of the present invention to provide a method and a control device for controlling an intake throttle valve of a diesel engine, which can perform a suitable opening control according to the above.

[0008]

In order to achieve the above object, the present invention is directed to a step number control based on a predetermined step position of a step motor drivingly connected to an intake throttle valve of a diesel engine. When the intake throttle valve is driven to open and close based on the above, the relationship between the predetermined step position of the step motor and the opening degree of the intake throttle valve is initialized based on confirmation of the fully open position of the intake throttle valve. In the intake throttle valve control method, before the initialization, the intake throttle valve is forcibly moved to a retracted position corresponding to an engine state by a drive step guarded to be equal to or less than the number of steps required from full opening to full closing of the intake throttle valve. The gist is to drive.

The invention described in claim 2 is the first invention.
In the intake throttle valve control method for a diesel engine described in the above, the gist is that the intake throttle valve is forcibly driven to a fully closed position on condition that an ignition switch of the engine is off and the engine is not stopped. I do.

[0010] Further, the invention according to claim 3 is based on claim 1.
Or in the method of controlling an intake throttle valve for a diesel engine according to item 2, wherein the ignition of the engine is turned on;
Alternatively, the gist of the invention is to forcibly drive the intake throttle valve to a fully open position on condition that the engine is in a stopped state even when an ignition switch is turned off.

[0011] The invention described in claim 4 is the same as the claim 3.
In the method of controlling an intake throttle valve for a diesel engine according to the above, when the intake throttle valve is forcibly driven to a fully open position, the drive of the step motor is limited based on confirmation of the full open position of the intake throttle valve. Is the gist.

The invention described in claim 5 is the first invention.
5. The method for controlling an intake throttle valve for a diesel engine according to any one of items 4 to 4, wherein the initialization is performed at least once during a continuous operation period from when the ignition switch is turned on to when the ignition switch is turned off. It is the gist that it is done.

According to a sixth aspect of the present invention, there is provided a diesel engine for opening and closing the intake throttle valve based on a step number control based on a predetermined step position of a step motor which is drivingly connected to the intake throttle valve of the diesel engine. In the intake throttle valve control device, the fully open position instructing means for instructing the fully open position of the intake throttle valve, and the predetermined step position serving as the reference of the step motor is initialized based on the fully open position instruction of the fully open position instructing means. Initializing means, and on the condition that initialization by the initializing means is not performed, the intake throttle valve is controlled by the number of drive steps guarded to be equal to or less than the number of steps required from full opening to full closing of the intake throttle valve. And a forcible driving means for forcibly driving the retracted position to a retreat position according to the engine state.

The invention described in claim 7 is the same as the claim 6.
The forcible drive means forcibly sets the intake throttle valve to the fully closed position on condition that an ignition switch of the internal combustion engine is off and the engine is not stopped. The gist is that it is driven.

[0015] The invention described in claim 8 is the same as the claim 6.
Or the intake throttle valve control device for a diesel engine according to 7, wherein the forcible driving means is provided on condition that an ignition switch of the engine is on, or that the engine is in a stopped state even if the ignition switch is off. The gist of the invention is to forcibly drive the intake throttle valve to the fully open position.

The invention according to claim 9 is the invention according to claim 6.
9. The intake throttle valve control device for a diesel engine according to any one of claims 8 to 8, wherein when the forcible drive means forcibly drives the intake throttle valve to a fully open position, the fully open position instructing means for the intake throttle valve fully opens the intake throttle valve. The gist of the present invention is to further include a drive limiting means for limiting the drive of the step motor at the position indicated by the position.

According to a tenth aspect of the present invention, in the intake throttle valve control device for a diesel engine according to any one of the sixth to ninth aspects, the initialization means includes a step of turning on the ignition switch. The point is that the initialization is performed at least once during a continuous operation period from when the power is turned off until the power is turned off.

According to the first and sixth aspects of the present invention, the intake throttle valve is brought into the engine state with the number of drive steps guarded to be equal to or less than the number of steps required for fully opening and closing the intake throttle valve. By forcibly driving to the corresponding retracted position, opening / closing drive exceeding the operation limit of the intake throttle valve can be suppressed, and the opening degree of the intake throttle valve can be grasped, for example, the initialization process has not been completed Even in a situation where it is not possible, it is possible to perform suitable opening degree control according to the engine state.

Here, the retracted position is an opening position of the intake throttle valve corresponding to "a value different from a 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.

When the ignition switch is turned off, it is necessary to stop the diesel engine quickly. According to the method and configuration according to the second and seventh aspects, the number of driving steps at this time is reduced. By guarding the number of steps required from fully open to fully closed, the intake throttle valve is forcibly driven to the fully closed position while preventing the intake throttle valve from reaching an abnormal opening even before initialization is completed. As a result, the intake air supply is cut off or greatly reduced, and the diesel engine can be stopped quickly.

On the other hand, when the ignition switch is on, it is desirable that the intake throttle valve be fully opened in order to secure an intake air amount larger than a required amount. Even when the switch is off, even when the diesel engine is in a stopped state, it is desirable to fully open the intake throttle valve in order to secure an intake air amount more than required at the next engine start. In this regard, according to the method and the configuration according to the third and eighth aspects, the intake throttle valve is moved to the fully open position while guarding the number of drive steps at this time to the number of steps required from fully open to fully closed. By forcibly driving the intake throttle valve, the intake throttle valve can be set to the fully open position while preventing the abnormal opening degree even before the initialization processing is completed.

According to the fourth and ninth aspects of the present invention, the driving of the stepping motor is limited based on the confirmation of the full open position when the intake throttle valve is forcibly driven to the full open position. Thus, even before the initialization is completed, the drive of the step motor can be reliably stopped at the fully open position of the intake throttle valve, and it is possible to prevent the intake throttle valve from becoming an abnormal opening beyond the full open position. become.

Also, while the ignition switch is turned off and the power supply to the stepping motor and its control device is interrupted, the intake throttle valve is forcibly driven from the outside, and the step position of the stepping motor and the intake throttle The correspondence with the opening of the valve may be lost.
According to the method and configuration described in No. 0, the correspondence is initialized at least once during a continuous operation period, thereby correcting a shift or the like and performing accurate opening control of the intake throttle valve. become able to.

[0024]

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS Hereinafter, an embodiment of an intake throttle valve control device for a diesel engine according to the present invention 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 opened and closed by a stepping 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 the 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.

In addition, the ECU 19 stores the accelerator opening information (accelerator opening information) detected by the accelerator opening sensor 18 including the atmospheric pressure information detected by the pressure sensor 6 and the 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
And the cooling water temperature information detected by the water temperature sensor 77 are also taken in.

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, there is provided a pressing portion 33 which can come into contact with 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.

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 accommodated, 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 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 the 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 aspect 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 according to the present embodiment, when the step motor 40 is rotated, the two excitation methods are selectively used. 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 this embodiment, the opening angle control of the intake throttle valve 4 is performed by defining the rotation angle per excitation phase mode switching 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, a method of driving the step motor 40 during the normal operation of the intake throttle valve 4 will be described. The CPU 60 of the ECU 19 calculates the target opening of the intake throttle valve 4 based on the detection signals of the various sensors and the engine operating state, and calculates the target step elstrg of the step motor 40 corresponding to the target opening. Note that the target step elstrg is defined as the number of steps from a reference step position where the step position of the step motor 40 at the fully open position of the intake throttle valve 4 is set to “0 step”. The larger the opening is on the closing side, the larger the value is set. The target step elstrg is corrected by the coolant temperature detected by the water temperature sensor 77, the intake air temperature detected by the intake air temperature sensor 78, the atmospheric pressure detected by the pressure sensor 6, and the like. The CPU 60 determines the target step els
Difference elsd between trg and current step elsact
The drive of the stepping motor 40 is controlled using l. In addition,
This current step elsact is similarly defined as the number of steps from the reference step position, and is set to a larger value as the current opening degree of the intake throttle valve 4 is closer to the closing side.

The difference elsdl is a positive value, that is, the target step elstrg is the current step elsact.
If the current opening degree of the intake throttle valve 4 is larger than the target opening degree, the stepping motor 4 is switched in the ascending order of the excitation phase mode so that the intake throttle valve 4 is closed.
The output shaft 41 is rotated. On the other hand, the difference elsofd
When l is a negative value, that is, when the target step elstrg is smaller than the current step elsact and the current opening degree of the intake throttle valve 4 is closer to the target opening degree, the excitation phase mode is switched in descending order. The output shaft 41 of the step motor 40 is rotated in a direction to open the intake throttle valve 4. In this way, the drive control of the step motor 40 is performed so that the current opening of the intake throttle valve 4 matches the target opening.

In this embodiment, when the excitation phase of the step motor 40 is one phase, or when the target step el
When the difference between strg and the current step elsact is one step, the step motor 40 is driven one step at a time in a 1-2-phase excitation mode, that is, every switching cycle of the excitation phase. In other cases, the step motor 40 is driven by a two-phase excitation method in which the step motor 40 is driven by two steps every switching period of the excitation phase.

Next, a specific control mode of the intake throttle valve 4 of the present embodiment will be described in detail with reference to FIGS. First, the drive control of the step motor 40 during the normal opening control of the intake throttle valve 4 will be described with reference to FIG.
It will be described based on. FIG. 11 shows the step motor 4
9 is a flowchart showing a control procedure of a normal drive control routine after a zero initialization process.

Upon shifting to this routine, the CPU 60
First, in step S100, the target step elstrg
And a difference elsdl between the current step elsact and the current step elsact.

Here, the target step elstrg is a value set as the step position of the step motor 40 corresponding to the target opening at the time of controlling the opening of the intake throttle valve 4.
The target step elstrg is set based on, for example, an intake air amount, an engine speed NE, and the like in the processing of another routine executed by the CPU 60 as a periodic interruption processing at a predetermined time interval.
The correction is made based on parameters such as the cooling water temperature, atmospheric pressure, and intake air temperature detected by the pressure sensor 7, the pressure sensor 6, the intake air temperature sensor 78, and the like. Also, this target step elstrg
The step position of the step motor 40 when the intake throttle valve 4 reaches the fully open position is defined as a reference step position, that is, “0” step, and the number of steps that increases as the motor 40 is driven in the valve closing direction is determined. Is set.
On the other hand, the current step elsact is the current step position of the step motor 40, and similarly the intake throttle valve 4
The step number of the step motor 40 at the fully open position is set as a reference, and the number of steps is set to a larger value as the step motor 40 is driven to the valve closing side. In the present embodiment, the target step elstrg and the current step elsact
Is used to control the opening degree of the intake throttle valve 4.

Now, as the processing S100, the difference elsdl
Is calculated, the CPU 60 determines in step S101 that the difference elsdl is “0”, that is, the current step e
It is determined whether or not lsact matches the target step elstrg. Here, if the difference elsdl is “0”, the excitation phase of the step motor 40 is maintained as it is, and the opening degree of the intake throttle valve 4 is also maintained as it is. Then, as the process S102, the CPU 60 turns off the valve open flag “exopen” and the valve close flag “exclose”, and then ends the process of this routine once.

Note that the valve opening flag “exopen” and the valve closing flag “exclose” are flags indicating the driving direction of the step motor 40. The CPU 60 drives the stepping motor 40 in a direction to open the intake throttle valve 4 when the valve open flag “exopen” is on, and in a direction to close the valve 4 when the valve close flag “exclose” is on. .

On the other hand, the difference el
If sdl is not "0", the CPU 60 executes the next process S1.
Shift to the processing of 03. As the process of this process S103, the CPU 60 compares the target step elstrg with the current step elsact, and
Is determined.

In step S103, the target step e
If it is determined that lstrg is larger, the CPU 60
Shifts to the processing of step S104. In step S104, the CPU 60 turns off the valve open flag "exopen" and turns on the valve close flag "exclose", and sets the driving direction of the step motor 40 to the valve closing direction. On the other hand, when it is determined that the current step 40 is larger, the CPU 60 turns on the valve open flag “exopen” and turns off the valve close flag “exclose” in the process of step S105, and sets the drive direction of the step motor 40 to the valve open direction. I do.

After determining the driving direction of the step motor 40 in this manner, the CPU 60 performs a process in step S106.
The excitation method at the time of driving the step motor 40 is determined. Here, the CPU 60 determines that the value of the current excitation phase mode of the step motor 40, that is, the value of the lower 3 bits (0 to 7) of the excitation phase corresponding step elstep shown in FIG. If the difference elsdl is 1, that is, if the current step elsact is one step before the target step elstrg, the CPU 60 sets the number of drive steps elsactdl to “1” in step S107, and To drive the step motor 40. On the other hand, in other cases, the CPU 60 determines in step S108 that the number of driving steps elsactdl
Is set to “2”, and the stepping motor 40
To drive. After determining the excitation method at the time of driving in this way, the CPU 60 determines the driving direction of the step motor 40 determined in the previous step S103 as the processing of step S109. Here, the valve opening flag e
If xopen is ON, that is, if the driving direction of the step motor 40 is the valve opening direction, the CPU 60 proceeds to step S110.
, The number of drive steps elsactdl is subtracted from the current step elsact. That is, when the step motor 40 is driven by the 1-2 phase excitation method, “
When “1” is driven by the two-phase excitation method, “2” is
It is subtracted from the current step elsact.

On the other hand, when the driving direction of the step motor 40 is the valve closing direction, the CPU 60 determines in step S111 that the current step elsact is equal to the number of driving steps e.
Add lsactdl. Also in this case, “1” is used in the case of the 1-2-phase excitation method, and “1” is used in the case of the two-phase excitation method.
2 "is added to the current step elsact.

After changing the current step elsact in this way, the CPU 60 determines in step S112 the sum of the updated current step elsact and a predetermined offset value elsof in the excitation phase corresponding step elste.
Let p. Note that the offset value elsof corresponds to the number of excitation phase modes of the step motor 40 at the reference step position set by the initialization processing described later. Then, the drive circuit 72 reads the lower three bits (0 to 7) of the excitation phase corresponding step elstep, and changes the excitation phase of the step motor 40 according to the value.

As described above, the drive control of the step motor 40 is performed so that the opening of the intake throttle valve 4 approaches the target opening and coincides with the target opening. Incidentally, as described above, the target step elstrg and the current step elsact are set with reference to the step position of the step motor 40 at the time when the intake throttle valve 4 is located at the fully open position. However, the step motor 40
Step motor 4 when stepping out of the motor or stopping the diesel engine 1
Due to the interruption of the current supply to 0, the opening degree of the intake throttle valve 4 for control grasped from the step position of the step motor 40 may not correspond to the actual opening degree of the intake throttle valve 4 in some cases. . In order to cope with such a situation, in the control device for the intake throttle valve 4 of the present embodiment, after the diesel engine 1 is started, when a predetermined condition is satisfied, an initialization process for taking the above-mentioned measures is performed. In this initialization process, the step position of the step motor 40 at the time when it is confirmed that the intake throttle valve 4 is located at the fully open position by switching the on / off state of the fully open switch 39 is set as the reference step position. It is done by setting.

Next, such initialization processing will be described. When the initialization process is started, the CPU 60 first checks the on / off state of the full-open switch 39. Then, the CPU 60 drives the step motor 40 in the direction in which the full-open switch 39 is switched, and the switch 39
The step position at the time when is switched is set as a 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. The above-described normal drive control of the step motor 40 is performed using the current step elsact thus set and the stored offset value elsof.

By the way, at the time of normal drive control, the excitation phase of the step motor 40 is changed by adding or subtracting the current step elsact as described above. e
lsact is unknown. Therefore, the drive of the step motor 40 cannot be controlled in the same manner as the normal drive control described above. Therefore, during the initialization process or before the completion of the initialization process, it is necessary to control the driving of the step motor 40 by a method different from the usual method.

Therefore, in this embodiment, when the opening degree of the intake throttle valve 4 is changed before the completion of the initialization processing, the excitation phase of the step motor 40 is changed by directly adding or subtracting the offset value elsof described above. To do it. Further, in the present embodiment, the drive of the step motor 40 is always controlled by the two-phase excitation method before the completion of the initialization processing. Therefore, when the step motor 40 is driven in the valve opening direction, the offset value elsof is set to “
2 ”is subtracted, and when driving in the valve closing direction,“
Until the initialization processing is completed, the current step elsact is set to “0.” By adding or subtracting the offset value elsof in this way, the value of the excitation phase-corresponding step elstep is also changed. Therefore, the drive circuit 72 changes the excitation phase of the step motor 40 based on the lower three bits (0 to 7) of the excitation phase corresponding step elstep, and
Can be controlled. At this time, the number of times the offset value elsof is added or subtracted is counted by the counter elsofc, and the operation amount of the intake throttle valve 4 is estimated from the value.

Hereinafter, the drive control of the step motor 40 before the completion of the initialization processing in the present embodiment will be described in detail with reference to the flowchart showing the control procedure of the drive control routine of FIG.

The processing of this routine is executed as an interrupt processing every time the step motor 40 is switched to 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 routine proceeds to the processing of this routine, the CPU 60 first determines whether or not the initialization processing has already been completed as processing S200. If the initialization process has been completed, the intake throttle valve 4 is switched from the current step elsact.
The actual opening of the step motor 40 can be ascertained, and the normal drive control of the step motor 40 described above can be performed. In this case, the CPU 60 proceeds to the process S201, and controls the opening degree of the intake throttle valve 4 based on the above-described normal drive control routine.

On the other hand, if the initialization process has not been completed, the CPU 60 shifts to the process of step S202.
In this process S202, the CPU 60 determines whether or not the IG (ignition) switch 20 is turned on.

If the IG switch 20 is on, the CPU 60 determines in step S203 whether or not the condition for executing the initialization process is satisfied. In the case of the present embodiment, when the starter switch 21 is off and the engine speed NE is 500 rpm or more, the initialization processing execution condition is satisfied. As described above, when the starter switch 21 is ON, the starter motor for starting the diesel engine 1 is being driven, and the engine 1 is not operating completely independently. When the engine speed NE is less than 500 rpm, the diesel engine 1 is operating at a low speed and is in an unstable state. In these cases,
The voltage supplied to the ECU 19 and the step motor 40 may decrease, and the operation of the full-open switch 39, the step motor 40, its drive circuit 72, the ECU 19, and the like becomes unstable, and there is a concern that the initialization process cannot be performed normally. Is done. Therefore, in the present embodiment, the initialization process is not executed in such an unstable state.

If the execution condition of the initialization process is satisfied in the above-described process S203, the CPU 60 executes the above-described initialization process in a process S204.
On the other hand, if the execution condition is not satisfied, the CPU 60 executes the processing of step S205 and thereafter, and controls the drive of the step motor 40 so as to position the intake throttle valve 4 at the fully open position. At this time, the operation of the diesel engine 1 is continuing, and it is necessary to secure a sufficient intake air amount. In addition,
The output of the diesel engine 1 is adjusted mainly based on the fuel injection amount control. If the minimum required intake air amount is secured by the mechanism, even if the intake air amount is further increased, the diesel engine 1 will be sufficiently adjusted. It is possible to continue driving. Therefore, it is desirable to open the intake throttle valve 4 as much as possible in order to secure a necessary or sufficient amount or more of the intake air amount because the opening degree of the intake throttle valve 4 is unknown and fine adjustment of the intake air amount is not possible. . That is, in this case, the fully open position is a retracted position of the intake throttle valve 4 which is desirable in the engine state of the diesel engine 1.

Here, the retracted position is an opening position of the intake throttle valve 4 corresponding to "a value different from a normal target value".
The retracted position means that the drive control of the step motor 40 is difficult and the opening degree control of the intake throttle valve 4 cannot be sufficiently performed. This is also the position of the opening of the intake throttle valve 4 that enables the opening.

Now, in step S205, the CPU 60 determines whether or not the fully open switch 39 is on.
If the full-open switch 39 is turned on, the intake throttle valve 4 has already been set to the full-open position, and no further opening adjustment is required. Therefore, the CPU 60 executes the processing S
As 207, the power supply to the step motor 40 is cut off,
While the intake throttle valve 4 is kept as it is, the processing of this routine is temporarily ended. After the intake throttle valve 4 is fully opened as described above, the power supply to the step motor 40 is cut off, so that the IG switch 20 can be left on for a long time without turning on the diesel engine 1. This also suppresses power consumption, heat generation of the motor 40, and the like.

In the control device of the present embodiment, control is performed such that when the engine 1 is stopped, the intake throttle valve 4 is located at the fully open position. As described above, the intake throttle valve 4 is urged toward the valve opening side by the return spring 27. Therefore, when the opening of the intake throttle valve 4 is not forcibly changed due to some external factor when the engine 1 is stopped, the intake throttle valve 4 is located at the fully open position when the engine 1 is started, The fully open switch 39 should be on.

On the other hand, when the full-open switch 39 is off, the CPU 60 controls the drive of the step motor 40 so as to open the intake throttle valve 4. At this time, the offset value elsof described above is used for driving the step motor 40.
Are directly added or subtracted. The operation amount of the intake throttle valve 4 at that time is grasped by the value of the counter elsofc. The value of this counter elsofc is set to “0” when the diesel engine 1 starts, and “1” is decremented every time the step motor 40 is driven two steps in the valve opening direction, and 2 in the valve closing direction. "1" is added each time the step is driven. Accordingly, the value of the counter elsofc indirectly represents the current step position of the step motor 40 relative to the step position at the time of starting the engine 1.

The CPU 60 determines whether or not the value of the counter elsofc is equal to or less than "-Kall" in step S206. This “Kall” is a constant, and the value thereof is set to the value of a counter elsofc corresponding to the number of steps of the step motor 40 when the intake throttle valve 4 is driven from the fully open position to the fully closed position. Therefore, even if the intake throttle valve 4 is at the fully closed position when the engine is started, if it is in a normal state, the intake throttle valve 4 reaches the fully open position before the value of the counter elsofc reaches "-Kall". , The fully open switch 39 should be on. Therefore, if the value of the counter elsofc exceeds "-Kall" in the process S206, the CPU 60 determines that some abnormality has occurred. Then, in step S207, the CPU 60 cuts off the power supply to the step motor 40, leaves the intake throttle valve 4 as it is, and ends the processing of this routine once.

Note that, as described above, the counter elsofc
Is caused by the failure of the full-open switch 39 and the on / off switching is not performed normally, the intake throttle valve 4 and the drive mechanism 5
Gears 29, 36, 37, 41, step motor 40
And the like, and the intake throttle valve 4 cannot be driven to open. In any case, if the step motor 40 is continuously driven, the intake throttle valve 4 may exceed the fully open position and open abnormally further to the valve opening side, or apply an overload to the motor 40 or the like. Becomes In this respect, in the present embodiment, such abnormal opening and overload are suppressed by adding a limit (guard) to the operation amount of the intake throttle valve 4 in the form of step S206, and the intake throttle valve 4 and the step motor 40 are controlled. Has increased the reliability.

On the other hand, if the value of the counter elsofc is larger than "-Kall" in the above processing S206,
The CPU 60 determines in step S212 that the offset value el
"2" from Sof and "1" from counter elsofc
Is subtracted, and the step motor 40 is driven two steps in the valve opening direction. After the intake throttle valve 4 is driven to open,
The CPU 60 once ends the processing of this routine.

As described above, under the condition that the IG switch 20 is on and the initialization processing condition is not satisfied, the intake throttle valve 4 is decremented by subtracting the offset value elsof by “2”.
Is driven in the direction to open the valve. Finally, when the intake throttle valve 4 is driven to the fully open position, the power supply to the step motor 40 is cut off, and the state is left as it is. At this time, the step motor 4
The operation amount of 0 is guarded by the entire operation amount of the motor 40, and the intake throttle valve 4 has an abnormal opening degree, and even if the step motor 40 exceeds the operation range, it continues to be driven and becomes overloaded. To prevent them from doing so.

Next, a description will be given of the processing when the IG switch 20 is off in the processing S202. In this case, the CPU 60 determines in step S208 whether the diesel engine 1 is stopped.
Here, it is determined that the diesel engine 1 is not stopped when the IG switch 20 is turned off and the operation of the engine 1 is still continued even though the stop request is issued. . In such a case, it is necessary to significantly reduce or shut off the intake air supplied to the engine 1 and stop the engine 1 promptly. That is, in this case, the fully closed position is a retracted position of the intake throttle valve 4 which is desirable in the engine state of the diesel engine 1. Therefore, here, the intake throttle valve 4
Is controlled to drive the step motor 40 in the valve closing direction.

In this case, in step S209, the CPU 60 determines whether or not the value of the counter elsofc is larger than “Kall”. When the value of the counter elsofc exceeds “Kall”, the intake throttle valve 4 is driven to the closing side by the amount of operation from the fully open position to the fully closed position, and is already located near the fully closed position. Should be.
Therefore, the CPU 60 is no longer able to
Is not performed, and the processing of this routine is temporarily terminated while the opening degree of the intake throttle valve 4 is maintained. On the other hand, when the value of the counter elsofc is equal to or smaller than “Kall”, the CPU 6
0 is the offset value elsof in the process S211.
Is added to “2”, and “1” is added to the counter elsofc,
After driving the step motor 40 to the valve closing side for two steps,
The processing of this routine is once ended.

Under the condition where the IG switch 20 is off and the engine 1 is not stopped, the intake throttle valve 4 is closed with the entire operation amount of the step motor 40 as a guard until the engine 1 is stopped. Then, the step motor 40 is driven in the direction, and finally the intake throttle valve 4 is fully closed. By closing the intake throttle valve 4, the intake air supplied to the engine 1 is reduced, and the engine 1 can be stopped immediately. Here, similarly, by restricting the valve closing drive of the intake throttle valve 4 by the amount of operation from the fully open position to the fully closed position, abnormal opening and overload are suppressed, and the intake throttle valve 4 and the step motor 40 are controlled. Improves reliability.

Next, the processing when it is determined in the processing S208 that the diesel engine 1 is stopped will be described. This determination is made when the engine 1 is in a state of being stopped by the driver's operation or other circumstances such as engine stall before the initialization processing is completed after the start. In this case, the CPU 60 proceeds to step S210.
The drive control of the step motor 40 is performed so that the intake throttle valve 4 is opened by the process of the process S212.

At this time, in the process S210, the CPU 6
0 determines whether or not the value of the counter elsofc is equal to or less than “0”. That is, in this case, the CPU 60
Is limited to the amount of operation that has been driven to the valve closing side up to now.
The operation amount of the intake throttle valve 4 is limited. And C
The PU 60 increments the counter elsoff by “2” from the offset value elsof until the value of the counter elsofc becomes “0” or less, that is, until it is determined that the intake throttle valve 4 is returned to the fully open position.
"1" is subtracted from c, and control is performed so that the step motor 40 is driven two steps in the valve opening direction. As described above, in the present embodiment, the intake throttle valve 4 is normally held at the fully open position when the engine 1 is started. Therefore, if any abnormality does not occur, the value of the counter elsoffc is set to "0". With this, it can be estimated that the intake throttle valve 4 is located at the fully open position.

Under the condition that the IG switch 20 is off and the engine 1 is stopped, the stepping motor is opened in the direction of opening the intake throttle valve 4 while guarding the number of steps required until the engine is stopped. The drive of the valve 40 is controlled, and finally the valve 4 is brought to the fully open position.

As described above, if the IG switch 20 is on and the initialization processing execution condition is not satisfied before the initialization processing is completed, the fully open switch 39 is turned on or the operation of the intake throttle valve 4 is started. The valve 4 is driven in the valve opening direction until the amount reaches the operation amount from the fully closed position to the fully opened position. If the initialization processing execution condition is satisfied, the initialization processing is performed, and thereafter, the normal opening control of the intake throttle valve 4 is performed.

On the other hand, even when the IG switch 20 is off, if the engine 1 is not stopped, the intake throttle valve 4 is closed, and the engine 1 is stopped immediately. At this time, the closing amount of the intake throttle valve 4 is limited to the operation amount from the fully open position to the fully closed position. Further, when the engine 1 is stopped, the intake throttle valve 4 is opened by an amount corresponding to the valve closed before the engine 1 is stopped.

As described above, in the present embodiment, the number of steps of driving the step motor 40 is counted, and the amount of operation of the intake throttle valve 4 is limited based on the counted number of steps, whereby the intake throttle valve 4 becomes abnormal. Problems such as an opening degree and an overload of the step motor 40 and the like are suppressed.

As described above, according to the present embodiment, the following effects can be obtained. (1) Even before the initialization process is completed, the number of steps driven from the start is counted, and the opening and closing of the intake throttle valve 4 is controlled based on the counted number. In addition, the opening degree of the intake throttle valve 4 can be adjusted according to the state of the full-open switch 39 and the operation state of the diesel engine 1.

(2) When the operation of the diesel engine 1 is continued before the completion of the initialization process, the intake throttle valve 4 is operated so as to be fully opened to secure a necessary and sufficient intake air amount. The operation of the engine 1 can be suitably maintained. Further, even when the IG switch 20 is turned off and the engine 1 is stopped, the step motor 40 is driven and controlled so that the opening of the intake throttle valve 4 is fully opened, so that the next time the engine is started. It is possible to secure an intake air amount larger than a required amount.

(3) If the engine 1 is not stopped even if the IG switch 20 is turned off before the completion of the initialization process, the intake throttle valve 4 is operated to be fully closed,
By reducing or shutting off the intake air amount, the engine 1 can be quickly stopped.

(4) By restricting the opening / closing drive amount of the intake throttle valve 4 in the above-mentioned situations (2) and (3) to the operation amount from the fully open position to the fully closed position, the intake throttle valve 4 is abnormally opened. Or the step motor 40 is overloaded, and the reliability of the intake throttle valve 4, the step motor 40, and the like can be improved.

(5) In the above situation (2),
Further, the drive of the step motor 40 is restricted by confirming the full open position by the full open switch 39, so that the intake throttle valve 4 can be reliably set to the full open position.

(6) When the intake throttle valve 4 is driven in the valve opening direction, if the fully open position is confirmed or if it is driven by the guard amount, the power supply to the step motor 40 is stopped. This makes it possible to suppress power consumption, heat generation of the step motor 40, and the like even when the IG switch 20 is kept on for a long time without turning on the diesel engine 1.

(7) The opening position of the intake throttle valve 4 is estimated on the basis of the number of steps of the step motor 40 driven from the start, and the opening / closing speed of the valve 4 is adjusted, so that the step motor 40 loses synchronism. It can be suppressed.

Note that the embodiment of the present invention may be modified as follows. In the present embodiment, when the intake throttle valve 4 is closed to near the fully closed position as described above, the intake throttle valve 4 also receives the urging force of the relief spring 31 in addition to the urging force of the return spring 27. Acts and is urged in the valve opening direction with a larger force. Therefore, if the intake throttle valve 4 is closed at the usual speed near the fully closed position, the driving torque of the step motor 40 cannot fully withstand the urging force, and there is a possibility that the step-out may occur. Therefore, when closing the intake throttle valve 4 in the vicinity of the fully closed position, drive control is performed such that the interval at which the excitation phase of the step motor 40 is switched is lengthened and the closing speed of the intake throttle valve 4 is reduced. It is desirable. However, as described above, the opening degree of the intake throttle valve 4 cannot be grasped from the current step elsact before the completion of the initialization processing. Therefore, it is assumed that the intake throttle valve 4 is in the fully open position when the engine 1 is started,
Based on the value of the counter elsofc, the valve 4 estimates the operation amount, and performs control to reduce the valve closing speed when it is estimated that the valve 4 is at the fully closed position. As described above, the current opening of the intake throttle valve 4 may be estimated based on the value of the counter elsofc, and the driving speed of the step motor 40 may be controlled based on the estimated opening.

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 that directly confirms that the throttle valve 4 is at the fully open position, or a type that is provided outside the throttle body 25 and that confirms the fully open position based on the rotation angle of the valve shaft 26, etc. Good. Further, the device does not necessarily need to be a switch as long as it can confirm the fully open position of the intake throttle valve 4 and give an instruction to that effect.

Next, technical ideas other than the inventions described in the claims, which can be understood from the embodiment, will be described below together with their effects. (1) In the intake throttle valve control method for a diesel engine according to any one of claims 1 to 5, the number of guarded drive steps when forcibly driving the intake throttle valve to a retracted position according to the engine state. And controlling the drive speed of the intake throttle valve based on the count value.

(2) In the intake throttle valve control device for a diesel engine according to any one of claims 6 to 10, the number of guarded drive steps is counted when the intake throttle valve is forcibly driven by the forcible driving means. An intake throttle valve control device for a diesel engine, further comprising: a count unit that performs the operation; and a drive speed changing unit that changes a drive speed of the intake throttle valve based on a count value of the count unit.

According to the above methods (1) and (2), the intake throttle calculated by the operation amount calculating means can be calculated even before the completion of the initialization process in which the opening degree of the intake throttle valve cannot be determined. The current opening degree of the intake throttle valve is estimated from the operation amount of the valve, and the operating speed of the intake throttle valve can be adjusted based on the estimated opening degree.

[0106]

According to the first and fifth aspects of the present invention, the intake throttle valve is controlled in accordance with the engine state by the number of drive steps guarded to be equal to or less than the number of steps required for fully opening and closing the intake throttle valve. Forced drive to the retracted position allows the opening and closing drive beyond the operating limit of the intake throttle valve to be suppressed, and the opening degree of the intake throttle valve cannot be grasped, for example, the initialization process is not completed Even in the situation, it is possible to perform a suitable opening control according to the engine state.

According to the second and sixth aspects of the present invention, when the ignition switch of the engine is off and the engine is not in a stopped state, the abnormal opening degree is obtained even if the initialization is not completed. Thus, the intake throttle valve can be forcibly driven to the fully closed position while preventing the intake air supply from being cut off or greatly reduced, and the diesel engine can be stopped quickly.

According to the third and seventh aspects of the present invention, when the ignition switch of the engine is turned on or the engine is stopped even when the ignition switch is turned off, the initialization processing is completed. Even if it is not necessary, the intake throttle valve can be forcibly driven to the fully open position while preventing an abnormal opening degree, so that the intake air amount to the diesel engine can be secured more than necessary. become.

According to the fourth and eighth aspects of the present invention, the drive of the stepping motor is limited based on the confirmation of the full open position when the intake throttle valve is forcibly driven to the full open position. Thus, even before the initialization is completed, the drive of the step motor can be reliably stopped at the fully open position of the intake throttle valve, and it is possible to prevent the intake throttle valve from becoming an abnormal opening beyond the full open position. become.

Furthermore, according to the method and the configuration according to the fifth and tenth aspects, the correspondence is initialized at least once during a continuous operation period, so that the correspondence is initialized while the ignition switch is turned off. Correction of the generated shift and the like can be performed, and accurate opening control of the intake throttle valve can be performed.

[Brief description of the drawings]

FIG. 1 is a schematic diagram showing a schematic configuration of a diesel engine to which a step motor type valve device according to an embodiment of the present invention is applied.

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 valve device of the embodiment.

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 structure of the step motor.

FIG. 9 is a schematic view showing the operation principle of the step motor.

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

FIG. 11 is an exemplary flowchart showing the initialization procedure of the valve device of the embodiment.

FIG. 12 is a flowchart similarly showing an initialization processing procedure;

[Explanation of symbols]

1 ... diesel engine, 2 ... intake passage, 4 ... intake throttle valve,
Reference numeral 5: intake throttle valve driving mechanism, 6: pressure sensor, 7: exhaust passage, 8: EGR passage, 9: EGR control valve, 19: electronic control unit (ECU), 20: ignition switch, 21
... starter switch, 26 ... valve shaft, 29 ... driven gear, 3
2 Lever, 33 Pressing part, 35 Support shaft, 36 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, 4
7 An phase coil, 48 Bp phase coil, 49 Bn phase coil, 60 CPU, 72 drive circuit, 77 water temperature sensor, 78 ambient temperature sensor.

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[Procedure amendment]

[Submission date] July 23, 1999

[Procedure amendment 1]

[Document name to be amended] Statement

[Correction target item name] Claim 1

[Correction method] Change

[Correction contents]

[Procedure amendment 2]

[Document name to be amended] Statement

[Correction target item name] Claim 6

[Correction method] Change

[Correction contents]

[Procedure amendment 3]

[Document name to be amended] Statement

[Correction target item name] 0008

[Correction method] Change

[Correction contents]

[0008]

In order to achieve the above object, the present invention is directed to a step number control based on a predetermined step position of a step motor drivingly connected to an intake throttle valve of a diesel engine. When the intake throttle valve is driven to open and close based on the above, the relationship between the predetermined step position of the step motor and the opening degree of the intake throttle valve is initialized based on confirmation of the fully open position of the intake throttle valve. In the intake throttle valve control method, the initialization may be performed.
Is not performed and the opening of the intake throttle valve is unknown.
To, by the driving step number of guard below the number of steps required for a fully closed from the fully open of the intake throttle valve, and its gist to force driven to the retracted position corresponding to the intake throttle valve to the engine state.

[Procedure amendment 4]

[Document name to be amended] Statement

[Correction target item name] 0013

[Correction method] Change

[Correction contents]

According to a sixth aspect of the present invention, there is provided a diesel engine for opening and closing the intake throttle valve based on a step number control based on a predetermined step position of a step motor which is drivingly connected to the intake throttle valve of the diesel engine. In the intake throttle valve control device, the fully open position instructing means for instructing the fully open position of the intake throttle valve, and the predetermined step position serving as the reference of the step motor is initialized based on the fully open position instruction of the fully open position instructing means Initialization means for performing initialization, and the intake throttle not being initialized by the initialization means.
When the degree of opening of the intake throttle valve is unknown , the intake throttle valve is forcibly driven to a retracted position according to the engine state with the number of drive steps guarded to be equal to or less than the number of steps required from full opening to full closing of the intake throttle valve. The gist of the present invention is to provide forcible driving means for performing the above.

[Procedure amendment 5]

[Document name to be amended] Statement

[Correction target item name] 0106

[Correction method] Change

[Correction contents]

[0106]

According to the first and sixth aspects of the present invention, the intake throttle valve is controlled in accordance with the engine state by the number of drive steps guarded to be equal to or less than the number of steps required for fully opening and closing the intake throttle valve. Forced drive to the retracted position allows the opening and closing drive beyond the operating limit of the intake throttle valve to be suppressed, and the opening degree of the intake throttle valve cannot be grasped, for example, the initialization process is not completed Even in the situation, it is possible to perform a suitable opening control according to the engine state.

[Procedure amendment 6]

[Document name to be amended] Statement

[Correction target item name]

[Correction method] Change

[Correction contents]

According to the second and seventh aspects of the present invention, when the ignition switch of the engine is off and the engine is not in a stopped state, the abnormal opening degree is obtained even if the initialization is not completed. Thus, the intake throttle valve can be forcibly driven to the fully closed position while preventing the intake air supply from being cut off or greatly reduced, and the diesel engine can be stopped quickly.

[Procedure amendment 7]

[Document name to be amended] Statement

[Correction target item name] 0108

[Correction method] Change

[Correction contents]

According to the third and eighth aspects of the present invention, when the ignition switch of the engine is turned on or the engine is stopped even if the ignition switch is turned off, the initialization process is completed. Even if it is not necessary, the intake throttle valve can be forcibly driven to the fully open position while preventing an abnormal opening degree, so that the intake air amount to the diesel engine can be secured more than necessary. become.

[Procedure amendment 8]

[Document name to be amended] Statement

[Correction target item name]

[Correction method] Change

[Correction contents]

According to the fourth and ninth aspects of the present invention, the drive of the stepping motor is restricted based on the confirmation of the full open position when the intake throttle valve is forcibly driven to the full open position. Thus, even before the initialization is completed, the drive of the step motor can be reliably stopped at the fully open position of the intake throttle valve, and it is possible to prevent the intake throttle valve from becoming an abnormal opening beyond the full open position. become.

Continued on the front page (51) Int.Cl. ⁶ Identification code FI H02P 8/08 H02P 8/00 301C

Claims (10)

[Claims] When opening and closing the intake throttle valve based on a step number control based on a predetermined step position of a step motor that is drivingly connected to an intake throttle valve of a diesel engine, a predetermined step position of the step motor is provided. A method of controlling the throttle valve of a diesel engine, which initializes the relationship between the opening degree of the throttle valve and the opening degree of the throttle valve based on the confirmation of the fully open position of the throttle valve. A method for controlling an intake throttle valve of a diesel engine, comprising forcibly driving the intake throttle valve to a retracted position corresponding to an engine state with a drive step number guarded to be equal to or less than the number of steps required for closing. 2. The intake throttle valve control for a diesel engine according to claim 1, wherein the intake throttle valve is forcibly driven to a fully closed position on condition that an ignition switch of the engine is off and the engine is not stopped. Method. 3. The intake throttle valve is forcibly driven to a fully open position on a condition that an ignition switch of the engine is turned on, or that the engine is stopped even if the ignition switch is turned off. A method for controlling an intake throttle valve of a diesel engine as described above. 4. The diesel engine according to claim 3, wherein when the intake throttle valve is forcibly driven to the full open position, the drive of the step motor is limited based on confirmation of the full open position of the intake throttle valve. Intake throttle valve control method. 5. The system according to claim 1, wherein said initialization is performed at least once during a continuous operation period from when the ignition switch is turned on to when it is turned off. The method for controlling an intake throttle valve of a diesel engine according to any one of the preceding claims. 6. A control device for an intake throttle valve of a diesel engine, which opens and closes the intake throttle valve based on a step number control based on a predetermined step position of a step motor driven and connected to the intake throttle valve of the diesel engine, Full-open position indicating means for indicating a full-open position of the intake throttle valve; initialization means for initializing the reference step position of the step motor based on the full-open position instruction of the full-open position indicating means; Under the condition that initialization by means has not been performed, the intake throttle valve is moved to the retracted position corresponding to the engine state with the number of drive steps guarded below the number of steps required from full opening to full closing of the intake throttle valve. An intake throttle valve control device for an intake throttle valve of a diesel engine, comprising: forced driving means for forcibly driving. 7. The forcible driving means for forcibly driving the intake throttle valve to a fully closed position on condition that an ignition switch of the internal combustion engine is turned off and the engine is not stopped. 3. The intake throttle valve control device for a diesel engine according to claim 1. 8. The forcibly driving means forcibly drives the intake throttle valve to a fully open position on condition that an ignition switch of the engine is turned on, or that the engine is stopped even when the ignition switch is turned off. An intake throttle valve control device for a diesel engine according to claim 6 or 7. 9. An intake throttle valve control device for a diesel engine according to claim 6, wherein said forced throttle drive means forcibly drives said intake throttle valve to a fully open position. An intake throttle valve control device for a diesel engine, further comprising drive limiting means for limiting the drive of the step motor at a position indicated by the full open position instruction means. 10. The initialization means according to claim 6, wherein said initialization means performs said initialization at least once during a continuous operation period from when the ignition switch is turned on to when it is turned off. An intake throttle valve control device for a diesel engine according to any one of claims 9 to 9.