JP2658496B2 - Failure determination and recovery method for DC motor type positioning device - Google Patents

Description

Description: TECHNICAL FIELD The present invention relates to a method for determining a failure of a DC motor type positioning device for positioning an object by driving the object with a DC motor.

(Prior Art) A DC motor type positioning device of this type is used by being incorporated in various systems. For example, a variable intake system in an internal combustion engine is known as one of the systems.

In this variable intake system, the length of the intake system of the internal combustion engine is varied by opening and closing a variable intake control valve. More specifically, in the middle of the main intake passage,
A variable intake control valve is provided, and a bypass intake passage is provided in the main intake passage so as to bypass the variable intake control valve. Therefore, if the engine has the above-described intake system, when the rotational speed of the internal combustion engine is relatively low, the variable intake control valve is closed to increase the effective passage length of the intake system. Is relatively high, by opening the variable intake control valve and shortening the effective passage length of the intake system, it is possible to increase the output of the internal combustion engine over a wide rotational speed range.

The above-described variable intake system incorporates a DC motor-type positioning device for opening and closing a variable intake control valve as an object. The DC motor-type positioning device includes a DC motor and a DC motor. A power transmission path is provided for connecting between the output shaft of the motor and the variable intake control valve. Accordingly, the DC motor type positioning device can drive the variable intake control valve to open and close by driving the DC motor.

The DC motor type positioning device includes a DC motor and a rotation speed sensor that detects the rotation speed of a rotation shaft included in a power transmission path and outputs a sensor signal thereof, and a control circuit that controls driving of the DC motor. The control circuit obtains the actual valve opening of the variable intake control valve based on the sensor signal from the rotation speed sensor, and adjusts the actual valve opening to the target valve opening. , And controls the driving of the DC motor.

The above-described DC motor type positioning device is not only obtained at a lower cost than a positioning device using a step motor in place of the DC motor, but also detects the actual valve opening of the variable intake control valve by a rotation speed sensor. Therefore, the valve opening of the variable intake control valve can be controlled with high accuracy.

(Problems to be Solved by the Invention) By the way, as apparent from the above description, when a failure occurs in the control function of the DC motor type positioning device, it becomes impossible to accurately control the valve opening of the variable intake control valve. Therefore, it is necessary to quickly detect a failure in the control function.
Here, as a failure of the control function of the DC motor type positioning device, first, a failure of the rotation speed sensor can be considered.
Conventionally, the failure is performed only by the diagnostic circuit when the operation of the positioning device is started,
During the operation, even if a failure occurs in the control function, the failure cannot be detected accurately.

Conversely, even if the control function of the positioning device is normal, when the operation is started, the operation is unstable, so that the diagnosis circuit may determine that the malfunction has occurred finally.

The present invention has been made on the basis of the above-described circumstances, and an object of the present invention is to provide a method for determining and returning a failure of a DC motor type positioning device capable of accurately and surely detecting a failure of its control function. To provide.

(Means for Solving the Problems) The present invention relates to a DC motor connected to a variable intake control valve, which is provided in an intake passage of an internal combustion engine and varies intake characteristics, via a power transmission path, and the DC motor and power A rotation speed sensor that detects a rotation speed of a rotation shaft included in the transmission path and outputs a sensor signal, and an actual valve opening of the variable intake control valve is obtained based on a sensor signal of the rotation speed sensor. A control circuit for controlling the rotation of the DC motor so that the valve opening reaches the target valve opening is applied to a DC motor type positioning device, and the failure determination / recovery method is based on the control operation of the DC motor type positioning device. Is started, it is determined whether or not the actual valve opening of the variable intake control valve has reached the target valve opening within a predetermined time. If this determination result is negative, the control function of the DC motor type positioning device is determined. Is determined to have failed. In the process in which the value of the failure determination counter is increased and the variable intake control valve is driven to the fully open position and the failure determination process is repeatedly performed every time the internal combustion engine is started, When the value of the failure determination counter is continuously increased and reaches a predetermined value, it is determined that a final failure has occurred, while the determination result is positive before the value of the failure determination counter reaches the predetermined value. Is characterized in that the value of the failure determination counter is cleared.

(Operation) According to the failure determination / return method of the present invention, the failure determination step is performed when the control operation by the positioning device is started. In this failure determination step, it is determined whether or not the actual valve opening of the variable intake control valve has reached the target valve opening within a predetermined time after the start of the control operation of the positioning device. In this case, the operation of the variable intake control valve is restored by increasing the value of the failure determination counter and driving the variable intake control valve to its fully open position.

When the value of the failure determination counter reaches a predetermined value in the process of repeatedly performing the failure determination process every time the internal combustion engine is started, the final failure of the positioning device is determined. However, if the determination result in the failure determination step becomes positive before the value of the failure determination counter reaches a predetermined value, the value of the failure determination counter is cleared, and the positioning device determines that the control function is normal. Is done.

Hereinafter, an embodiment of the present invention will be described with reference to the drawings.

FIG. 1 shows an internal combustion engine for a vehicle provided with a variable intake system, which is, for example, a V-type 6-cylinder gasoline engine. A main intake passage 2 and an exhaust passage 3 are connected to each combustion chamber 1 of the internal combustion engine, respectively, and each of the main intake passage 2 and the exhaust passage 3 is connected to the combustion chamber 1 so as to face the combustion chamber 1. 4 and exhaust valve 5
Is arranged.

An air cleaner 6, a throttle valve 7, and an injector 8 are sequentially arranged in the main intake passage 2 from the upstream side, and a three-way catalytic converter 9 and a muffler (not shown) are arranged in the exhaust passage 3 from the upstream side. Are arranged in order. In the main intake passage 2, a part located downstream of the throttle valve 7 is a surge tank 10.
Further, the injectors 8 are provided in the intake manifold portion of the main intake passage 2 for each cylinder.

Although not shown, the throttle valve 7 is connected to an accelerator pedal in the vehicle cabin via an accelerator wire or the like, whereby the opening degree of the throttle valve 7 can be varied according to the amount of depression of the accelerator pedal. It has become so.

The variable intake system includes a variable intake control valve 11 located immediately downstream of the surge tank 10 in the main intake passage 2, and a bypass intake passage that bypasses both the variable intake control valve 11 and the surge tank 10. It has 12 and. When the variable intake control valve 11 is in the fully closed position shown by the solid line in FIG. 1, the intake air passes from the main intake passage 2 via the bypass intake passage 12 and returns to the main intake passage 2 again. Through the combustion chamber 1. On the other hand, when the variable intake control valve 11 is at the fully open position indicated by the broken line in FIG.
Instead of passing through the detour intake passage 12, the combustion chamber 1 reaches the combustion chamber 1 through a short intake path including only the main intake passage 2.

The above-described variable intake system incorporates a DC motor type positioning device for controlling the opening degree of the variable intake control valve 11, and the positioning device will be described below.

First, the positioning device is a DC motor, that is, a DC motor.
The DC motor 13 includes a small DC motor with a brush. As shown in FIG. 2, the DC motor 13 is accommodated in the main intake passage 2 in a casing 14 attached to an outer wall near the variable intake control valve 11.

The output shaft 15 of the DC motor 13 is connected to the variable intake control valve 11 via a power transmission path 16. That is, the power transmission path 16 includes a gear 17 attached to the output shaft 15 of the DC motor 13, and a gear 19 meshed with the gear 17 via the intermediate gear 18. The gear 19 is mounted on a rotating shaft 20, which is rotatably supported in the casing 14 via several bearings 21.

A worm gear 22 is attached to one end of the rotating shaft 20, and a worm wheel 23 is attached to the worm gear 22.
Are engaged. The worm wheel 23 is attached to a valve shaft 24 of the variable intake control valve 11 (see FIG. 1).

Therefore, if the DC motor 13 and the variable intake control valve 11 are connected by the power transmission path 16 described above, the DC motor 13 is driven to rotate the valve shaft 24 of the variable intake control valve 11. Accordingly, the opening degree of the variable intake control valve 11 can be varied.

Further, a pair of rotation speed sensors, that is, first and second rotation speed sensors 25 and 26 are arranged on the other end side of the rotation shaft 20. These first and second rotation speed sensors 25, 26
As shown in FIGS. 3 and 4, respectively, these rotational speed sensors have basically the same structure, and therefore, only the first rotational speed sensor 25 will be described here.

The first rotation speed sensor 25 includes a ring magnet 27a fixed to the peripheral surface of the rotation shaft 20. This ring magnet 27a is attached to the rotating shaft 20 via a sleeve 28 made of a non-magnetic material, or by forming the rotating shaft 20 from a non-magnetic material,
It can be directly attached to the rotating shaft 20. As shown in FIG. 3, the ring magnet 27a has a half-peripheral surface magnetized to the N-pole and the other half-peripheral surface has S
Magnetized to poles. In addition, in FIG.
The boundary is indicated by a broken line X so that the region of the magnetic pole at 27a is clear. And the ring magnet 27a
A magnetic probe 29a made of a Hall IC is arranged near the outer peripheral surface of the above so as to always face the outer peripheral surface. The magnetic probe 29a outputs a signal corresponding to the magnetic pole of the ring magnet 27a when the ring magnet 27a is rotated together with the rotating shaft 20. That is, when the ring magnet 27a rotates with respect to the magnetic probe 29a, the magnetic probe 29a detects a different magnetic pole every half rotation of the ring magnet 27a. The magnetic probe 29a is turned on to output an L-level signal, and when detecting the S pole of the ring magnet 27a, the magnetic probe 29a is turned off and outputs an H-level signal. . Therefore, with the rotation of the rotation shaft 20, the signal from the magnetic probe 29a, that is, the signal from the first rotation speed sensor 25 is output in a pulsed manner as indicated by P1 in FIG.

Since the second rotation speed sensor 26 has the same structure as the first rotation speed sensor 25 as described above,
Members having the same functions as the members of the rotation speed sensor 25 are denoted by the same reference numerals in which only the suffix is replaced by b, and the description thereof will be omitted, and only different points will be described below.

In the case of the second rotational speed sensor 26, as is apparent from a comparison between FIG. 3 and FIG.
The rotation angle phase of the attachment to 0 is different from that of the ring magnet 27a in the first rotation speed sensor 25 by 90 °. Accordingly, the output from the magnetic probe 29b, that is, the output from the second rotational speed sensor 26 is indicated by P2 in FIG.

The signals from the first and second rotation speed sensors 25 and 26 are
As shown in the figure, an electronic control unit 30 is provided as a control circuit for controlling the drive of the DC motor 13, and the electronic control unit 30 includes an engine speed sensor 31, Air flow sensor 32, throttle sensor,
Atmospheric pressure sensor, intake air temperature sensor, an idle switch, O ₂ sensor, a high temperature sensor, a knock sensor, a water temperature sensor, so that the signal from the TDC sensor, and the like are also inputted.
FIG. 1 shows only the engine speed sensor 31 and the air flow sensor 32 among these various sensors, and the first and second rotational speed sensors also have the magnetic probe 29a. Only is shown.

As shown schematically in FIG. 6, the electronic control unit 30 includes an actual valve opening detection unit 33 to which signals from the first and second rotation speed sensors 25 and 26 are input, and an engine speed sensor. A target valve opening setting unit 34 to which a signal from 31 is input, these actual valve opening detecting units 33, a target valve opening setting unit 34, and an air flow sensor 32 are connected to each other to control the driving of the DC motor 13. The control unit 35 includes a control unit 35 that outputs a control signal and also includes a failure determination circuit of the positioning device described above. Note that the engine speed sensor 31 may be also used as a crank angle sensor that detects the crank angle of the internal combustion engine.

Next, the operation control of the variable intake system will be described with reference to the flowcharts shown in FIGS. First, when the internal combustion engine is started by being turned on by an ignition key, the initialization is performed in step S1. In this initialization, for example, various flags are reset to 0, An appropriate value is set to the initial value of. Then, in the next step S2, an initialization process is performed, and in this initialization process, the variable intake control valve 11 is positioned at, for example, a fully closed position. Thereafter, after a control step (not shown) is performed, the process proceeds to step S3. In this step S3, it is determined whether or not 1 is set to the fail-safe flag FSF. Here, in the initial setting in step S1,
Since the fail-safe flag FSF has been reset to 0, the process proceeds to step S4, where the valve opening control of the variable intake control valve 11 is performed.

Here, the content in step S4 will be specifically described.
First, the actual valve opening detector 33 detects the actual valve opening of the variable intake control valve 11 based on the signals from the first and second rotation speed sensors 25 and 26 and supplies the detected valve opening to the controller 35. That is, immediately after the control operation of the variable intake system is started, the actual valve opening of the variable intake control valve 11 is fully closed by performing the previous step S2.

In the target valve opening setting section 34, a target valve opening of the variable intake control valve 11 is set based on a signal from the engine speed sensor 31, and the target valve opening is also set in the control section 35. Supplied to Here, the target valve opening is determined from the map shown in FIG. 10 or a function defining this map. As is clear from FIG. 10, the target valve opening of the variable intake control valve 11 is fully closed when the engine speed of the internal combustion engine is in a low speed range below a low speed value N1 (for example, around 3500 rpm), and the engine speed is reduced. Low speed value N1
It is set to be fully open in the high speed range higher than the high speed value N2 (for example, around 4500 rpm), and the low speed value
In the transition region between N1 and the high speed value N2, the valve opening is set to gradually increase from fully closed to fully open as the engine speed increases.

In the actual valve opening detection unit 33 and the target valve opening setting unit 34,
When the actual valve opening and the target valve opening of the variable intake control valve 11 are obtained, these are compared in the control unit 35, and the actual valve opening matches the target valve opening from the control unit 35. A drive control signal is output to the DC motor 13 in order to perform this.

When the rotating shaft 20 is rotated by the driving of the DC motor 13,
As described above, the valve shaft 24 of the variable intake control valve 11 is rotated, and the actual valve opening changes. On the other hand, with the rotation of the rotation shaft 20, the first and second rotation speed sensors 25, Since a pulse signal as shown in FIG. 5 is output from 26, the actual valve opening detection section 33 counts the number of pulses from at least one of the rotation speed sensors, and The actual valve opening of the variable intake control valve 11 can be constantly calculated based on the closed position, and the drive of the DC motor 13 is stopped when the actual valve opening matches the target valve opening. Will be.

In the case of this embodiment, the rotation shaft 20 is provided with two sensors, the first and second rotation speed sensors 25 and 26,
By comparing the overlapping state of the output patterns from the first and second rotation speed sensors 25 and 26, it is possible to detect whether the DC motor 13 is in the forward rotation state or in the reverse rotation state. This is convenient when the actual valve opening of the variable intake control valve 11 is obtained from addition and subtraction of the number of pulses.

Here, as is evident from the target valve opening characteristic shown in FIG. 10, the actual valve opening of the variable intake control valve 11 is kept fully closed when the engine speed is equal to or lower than N1, so that the internal The intake air supplied to the combustion chamber 1 of the engine flows through a long effective intake passage via the bypass intake passage 12. On the other hand, when the engine speed is equal to or higher than N2, the variable intake control valve 11 Is maintained at the fully opened position, the intake air supplied to the combustion chamber 1 of the internal combustion engine flows through the short effective intake passage only through the main intake passage 2. In addition, when the engine speed is between N1 and N2, the actual valve opening of the variable intake control valve 11 is, for example, 1/4 Each time, the actual valve opening is controlled so as to increase.

Accordingly, the output torque of the internal combustion engine is as shown in FIG. 11, and as apparent from FIG. 11, a high output torque can be obtained over the entire range of the engine speed, and the variable intake Fluctuations in the output torque when the control valve 11 shifts from fully closed to fully open can also be suppressed to a small value.

After the actual valve opening of the variable intake control valve 11 is controlled in accordance with the engine speed as described above, in the present invention, the direct current is controlled in accordance with the flowcharts shown in FIGS. The failure determination of the motor type positioning device is performed. Here, this failure determination includes a) that the battery voltage of the DC motor 13 is equal to or higher than an allowable level, b) that 1 second or more has elapsed since the start of the internal combustion engine, and c) that the initialization process in step S2 has already been performed. It is implemented on condition that it is completed. When the failure determination is restarted after the battery voltage has once dropped below the allowable level, the failure determination is performed when the battery voltage is equal to the allowable level +
It is preferable that the operation be restarted on condition that it has reached α or more.

In the failure determination of the positioning device, in step S5,
It is determined whether or not the actual valve opening of the variable intake control valve 11 matches the target valve opening. Here, if the determination is positive (Y), the process proceeds to step S6, and after each of the fail counter FC and the failure flag is reset to 0, the process proceeds to step S3.
The subsequent steps will be repeated. Here, it should be noted that the fail counter FC is constituted by a nonvolatile memory.

On the other hand, if the determination in step S5 is negative (N), then in next step S7, it is determined whether 1 is set in the failure flag. Here, at the start of the control, since the failure flag has been reset to 0 in the previous step S1, the determination in step S7 is negative (N), the process proceeds to step S8, and the failure determination is performed. A predetermined time T is set in a subtraction timer as a timer. Here, the predetermined time T is set such that the battery voltage of the DC motor 13 has dropped to near the allowable level, or in consideration of other worst conditions, at least the valve opening of the variable intake control valve 11 is changed from fully closed to fully open. Alternatively, the time is set to be equal to or longer than the time required for changing from the fully open state to the fully closed state and not to damage the DC motor 13 due to the lock current.

Then, in the next step S9, 1 is set to the failure flag, and in step S10, it is determined whether or not the value of the subtraction timer has reached 0. Here, immediately after the determination in the previous step S5 is negative (N), the step
Since the determination in S10 is negative (N), the steps after step S3 are repeated. However, when the process reaches step S7 again, 1 is already set in the failure flag. From step S7, step S10 is executed, bypassing steps S8 and S9.

Then, before the determination in step S10 becomes positive (Y),
If the determination in step S5 is positive (Y), in step S6, each of the fail counter FC and the failure flag is set to 0.
, The above steps are repeated. However, if the determination at step S10 becomes positive (Y) without the determination at step S5 becoming positive (Y), in other words, the variable intake control valve
11 actual valve opening within the predetermined time set in step S8,
If the target valve opening has not been reached, the process proceeds to step S11,
1 is added to the value of the fail counter FC, whereby
It is determined that the positioning device has failed. Then, in the next step S12, it is determined whether or not the value of the fail counter FC has reached 4, but at this point, the determination is no (N), and the process proceeds to step S14.

In step S14, the DC motor 13 is turned on for a certain period of time.
For example, a drive signal for driving in one direction for the above-described predetermined time T is output from the electronic control unit 30, whereby the variable intake control valve 11 is positioned at the fully open position. As a result, the determination in step S10 described above becomes positive (Y), and
Even if it is determined that the positioning device has failed, if the failure is a failure of the first and second rotation speed sensors 25 and 26, the variable intake control valve 11 can be positioned at the fully open position. When the variable intake control valve 11 is positioned at the fully open position when it is determined that the positioning device has failed, it is possible to prevent the output torque of the internal combustion engine from decreasing even in a high-speed operation range.

Thereafter, in step S15, 1 is set to the failsafe flag FSF, and the steps after step S3 are executed. At this time, the determination in step S3 is always positive (Y ), The next step S4 is not executed, whereby the operation of the variable intake system is stopped until the internal combustion engine is keyed off.

Thereafter, if the internal combustion engine is turned on again and started, the steps from step S1 are performed. In this case, however, the determination in step S10 is positive (Y), and the positioning device fails. When it is determined that
In the next step S11, after 1 is further added to the value of the fail counter FC, the step S1 of the steps S14 and S15 is performed.
By performing steps 4 and 15, the operation of the variable intake system is stopped until the internal combustion engine is turned off.

Then, the start and stop of the internal combustion engine are repeated, and when the value of the fail counter FC reaches 4, the discrimination starts at this time in step S12 and becomes positive (Y) at step S13.
After the diagnostic code is stored in step S13, steps S14 and S15 are performed, and the operation of the variable intake system is stopped. Here, when step S13 is performed, the fail lamp arranged in the vehicle may be turned on.

Before the determination in step S12 becomes positive (Y),
If the determination in step S5 is positive (Y), the failure counter FC is reset to 0 by performing step S6.

(Effects of the Invention) As described above, according to the method for determining and restoring the failure of the DC motor type positioning device of the present invention, the failure determination step is performed when the control operation of the positioning device is started. In the process, since it is determined whether or not the actual valve opening of the variable intake control valve has reached the target valve opening, a failure of the positioning device can be detected even during its operation. Then, when a failure at this point is detected, the value of the failure determination counter is increased in a failure determination step,
Since the variable intake control valve is driven and maintained at the fully open position, thereafter, the intake characteristics of the variable intake control valve can be maintained at, for example, characteristics suitable for a high-speed operation range of the internal combustion engine, and the output of the internal combustion engine can be maintained. The drop can be prevented.

Further, in the process in which the failure determination step is repeatedly performed every time the internal combustion engine is started, the value of the failure determination counter continuously increases, and when the value reaches a predetermined value, the final failure of the positioning device is determined. As a result, the failure of the positioning device can be reliably detected. On the other hand, before the value of the failure determination counter reaches the predetermined value, if the determination result in the failure determination step is positive, that is, if the variable intake control valve is operating normally, the value of the failure determination counter is cleared. As a result, the positioning device is determined to be operating normally. Therefore, according to the present invention, the final failure of the positioning device is not determined by looking at only one failure condition, so that even if the operation of the positioning device is temporarily unstable, the final failure is not determined. There is an advantage that a trouble can be detected with high accuracy.

[Brief description of the drawings]

The drawings show an embodiment of the present invention. FIG. 1 is a schematic sectional view of an internal combustion engine having a variable intake system, and FIG.
FIG. 3 and FIG. 4 are cross-sectional views showing the configuration of the positioning device, and FIG.
FIG. 6 is a graph showing respective outputs from the first and second rotation speed sensors, FIG. 6 is a block diagram of an electronic control unit,
7 to 9 are flowcharts for explaining the control operation of the variable intake system, FIG. 10 is a graph showing target valve opening characteristics of the variable intake control valve, and FIG. 4 is a graph showing a relationship between an output torque of an internal combustion engine obtained by an operation and an engine speed. 2: Main intake passage, 10: Surge tank, 11: Variable intake control valve, 12: Detour intake passage, 13: DC motor, 16: Power transmission path, 25, 26: Rotation speed sensor, 30: Electronic control unit, 31 ... Engine speed sensor.

 ──────────────────────────────────────────────────続 き Continuation of the front page (56) References JP-A-61-8435 (JP, A) JP-A-63-65125 (JP, A) JP-A-2-16328 (JP, A) 22835 (JP, U)

Claims (1)

(57) [Claims] 1. A DC motor connected to a variable intake control valve provided in an intake passage of an internal combustion engine and varying intake characteristics via a power transmission path, and a rotating shaft included in the DC motor and the power transmission path. A rotational speed sensor that detects the rotational speed of the variable intake control valve and outputs a sensor signal, and an actual valve opening of the variable intake control valve is obtained based on the sensor signal of the rotational speed sensor. And a control circuit for controlling the rotation of the DC motor so that the variable intake control valve is controlled within a predetermined time when the control operation of the DC motor type positioning device is started. It is determined whether or not the actual valve opening has reached the target valve opening.If this determination result is negative, it is determined that a failure has occurred in the control function of the DC motor type positioning device, and the failure determination counter has With increasing value A failure determination step of driving the variable intake control valve to the fully open position is performed. In a process in which the failure determination step is repeatedly performed every time the internal combustion engine is started, the value of the failure determination counter is continuously increased. When the value of the failure determination counter is determined to be positive before the value of the failure determination counter reaches the predetermined value, the failure determination counter is determined when the value of the failure determination counter reaches the predetermined value. A method for determining and recovering from a failure in a DC motor type positioning device, characterized by clearing the value of