JP4390521B2 - In-vehicle motor failure detection method and failure detection apparatus - Google Patents

Description

  The present invention relates to a failure detection method and a failure detection apparatus for an in-vehicle motor that detects disconnection of a stepper motor for idle speed control mounted on a vehicle and a ground fault.

  Conventionally, in idling speed control (ISC) of an automobile, a flow control valve provided in an auxiliary air passage that bypasses a throttle valve is opened and closed so that an engine speed in an idle operation state becomes a target speed considering a load and the like. The flow rate of the intake air is controlled automatically after the engine is started.

  The opening / closing control of the flow rate control valve is usually performed by an idle speed control stepper motor (hereinafter referred to as ISC stepper motor) mounted on the vehicle (see, for example, Patent Document 1).

  The stepper motor is also called a step motor or a stepping motor, and the most common one is a two-phase type, and there are a unipolar drive method and a bipolar drive method as its drive method. When performing low speed operation such as opening / closing control or for miniaturization, a bipolar drive system is adopted.

  The drive control of the two-phase bipolar drive system of the ISC stepper motor mounted on the vehicle is generally performed by an electronically controlled fuel injection device having the configuration shown in FIG.

That, ISC stepper motor 2 mounted on the vehicle 1 in FIG. 5 is a scan Te' Pamota two-phase bipolar drive, in accordance with the excitation pattern, the control unit (ECU) 3 of the electronic control fuel injection device of the vehicle 1 Between the both ends of the A phase stator coil (A coil) 2a of the ISC stepper motor 2 from the A phase terminals A1 and A2 of the provided drive unit 4a , for example, the stator coil of FIG. 6 and FIG. As shown by the voltage Va, an excitation voltage alternating between positive (+) and reverse (−) is applied in the period τ, and the B-phase stator of the stepper motor 2 from the B-phase terminals B1 and B2 of the drive unit 4. An excitation voltage whose phase is shifted by 90 degrees from the excitation voltage of the coil 2a is applied between both ends of the coil (B coil) 2b, for example, as shown by the inter-terminal voltage Vb in FIGS. 6 and 7B. Is done.

  Based on the application of both excitation voltages, the excitation pattern of the ISC stepper motor 2 switches every τ / 2 (for example, 5 ms) and changes repeatedly to four patterns “1”, “2”, “3”, “4”. Then, the ISC stepper motor 2 is excited and driven by the two-phase bipolar drive system, and advances one step every τ / 2.

  The pattern “1” is “Va, Vb = normal, normal”, the pattern “2” is “Va, Vb = normal, reverse”, the pattern “3” is “Va, Vb = reverse, reverse”, and the pattern “4”. "Is a combination of" Va, Vb = reverse, positive ".

  By the two-phase bipolar drive, the ISC stepper motor 2 advances one step in one direction or the other direction every τ / 2, and the flow control valve is opened and closed by the rotation of the motor shaft. Note that, when the flow control valve is opened and when the flow control valve is closed, the direction of change of the both excitation drive voltage patterns is reversed.

  By the way, the ISC stepper motor 2 is located in a so-called engine room of the vehicle 1, and the coil may be disconnected due to secular change or the like, and the power supply harness is long. (Short circuit) may occur.

  When the disconnection or ground fault occurs in the ISC stepper motor 2 including the harness, the idling engine speed may be abnormally increased or decreased, and the safety of traveling may be impaired. For this reason, it is necessary to quickly detect the occurrence of the failure and take measures such as stopping the step of the ISC stepper motor 2.

Therefore, regarding the disconnection of the stepper motor such as the ISC stepper motor 2 used for electronic control of opening and closing of the throttle valve of the automobile engine and the flow control valve, and the ground fault, the voltage between the stator coils (stator Coil voltage) and a predetermined voltage are compared by a comparator, and it is determined whether the voltage across the coil exceeds the predetermined voltage from the change in the output level. Based on this determination, the excitation pattern is switched and the applied voltage is It has been proposed to immediately monitor whether or not a back electromotive voltage greater than the applied voltage (power supply voltage) is generated immediately after being shut off (disappeared), and to detect that back electromotive voltage does not occur. (For example, refer to Patent Document 2).
Japanese Utility Model Publication No. 5-32748 ([0009], FIG. 1) Japanese Patent Laid-Open No. 11-356093 ([0009], [0019]-[0021], FIG. 2)

  As in the prior art, the stator coil voltage of the ISC stepper motor 2 is compared with a predetermined voltage by a comparator, and a disconnection of the ISC stepper motor 2 or occurrence of a ground fault is detected from a change in the output level of the comparator. In this case, the input / output of the comparator is likely to fluctuate due to the influence of noise such as noise inside and outside the vehicle 1, so that there is a problem that erroneous detection of a disconnection or a ground fault occurs easily. There is a risk of mistakes, and in some cases, it may be difficult to restart the engine.

Meanwhile, the driver integrated circuit forming the driving unit of the stepper motor of two-phase bipolar drive such as ISC stepper motor 2 (hereinafter, the integrated circuit and IC) as shown in FIG. 8, Infineon Technologies's (Infineon Technologies AG) Ltd. A two-phase stepper motor motor driver IC5 of model number TLE4729G (Germany) is commercially available.

  The driver IC 5 outputs excitation output terminals a1, a2, b1, b2 connected to the terminals A1, A2, B1, B2 of FIG. 5 and first and second error flag terminals e1 that output 2-bit error flags. , E2.

Then, when the stepper motor driver IC5 is provided, for example, in the drive unit 4a of FIG. 5 to cause disconnection or ground fault (GND short circuit) of the ISC stepper motor 2, the first error flag ERR1 output from the error flag terminal e1. The second error flag ERR2 output from the error flag terminal e2 changes in level as shown in FIGS. 6C and 6D when the disconnection occurs, and when the ground fault occurs, FIGS. The level changes as shown in d).

  That is, when a disconnection occurs in, for example, the coil 2a of the ISC stepper motor 2, as shown in FIG. 6A, a pulse P having a large back electromotive voltage is not generated in the voltage Va immediately after the occurrence of the disconnection tα. The stator coil voltage of the coil 2a becomes abnormal. At this time, the first error flag ERR1 output from the error flag terminal e1 is changed from a high level H as a normal detection level to a low level (error level) as an abnormality detection level. After falling to L, even if a pulse P is generated in the inter-terminal voltage Vb, the first error flag ERR1 is kept at the low level L unless the pulse P is generated in the inter-terminal voltage Va.

  Further, for example, when a ground fault occurs in the coil 2a or its power supply harness at tβ in FIG. 7, the voltage Va disappears, and the stator coil voltage of the coil 2a becomes abnormal, as shown in FIG. The excitation pattern immediately after the occurrence of the ground fault does not become a normal “1” pattern due to the disappearance of the voltage Va between the terminals, and at this time, the second error flag ERR2 output from the error flag terminal e2 becomes the low level L. Fall down.

  Note that the level of the error flags ERR1 and ERR2 similarly changes when the coil 2b is disconnected or a ground fault occurs.

  Therefore, it is conceivable that an error detection signal of the ISC stepper motor 2 is formed by the error flags ERR1 and 2, and the disconnection of the ISC stepper motor 2 and the occurrence of a ground fault are detected from the level change of the error flags ERR1 and 2. In this case, since the falling of the error flags ERR1 and LR2 to the low level L has occurred, if the occurrence of the failure is detected immediately, the voltages Va and Vb are also influenced by disturbances such as noise inside and outside the vehicle 1. Therefore, erroneous detection easily occurs as in the case where the output signal of the comparator is detected from the level change as an abnormality detection signal.

  Moreover, even if the error flag ERR2 is changed to the low level L due to the occurrence of a ground fault as shown in FIG. 7D, the error flag ERR2 returns to the high level H when a certain excitation pattern is obtained thereafter. Therefore, it is extremely difficult to distinguish whether the level change is due to the influence of disturbance such as noise.

  Therefore, there is a problem that it is impossible to reliably detect the disconnection of the ISC stepper motor 2 and the occurrence of a ground fault using the error flags ERR1 and ERR2 without erroneous detection.

  An object of the present invention is to detect a disconnection or a ground fault of an ISC stepper motor (including its harness) mounted on a vehicle such as the ISC stepper motor 2 as quickly and reliably as possible without erroneous detection.

In order to achieve the above-described object, the on-vehicle motor failure detection method of the present invention is an excitation drive by a two-phase bipolar drive system based on an open / close command for opening / closing a flow control valve in order to set the engine speed to a target speed. When the abnormality detection signal that changes from the normal detection level to the abnormal detection level due to an abnormality in the stator coil voltage of the stepper motor for idle speed control of the vehicle that has reached the abnormal detection level, the excitation pattern of the stepper motor is cycled. The stepper motor is forcibly driven in the same rotational direction regardless of the open / close command until the change occurs, and the abnormality detection signal is generated each time the stepper motor advances one step while the excitation pattern changes by one cycle by the forcible drive. Is the abnormality detection level, the number of abnormality detections is incremented by one, and the excitation pattern makes a round-trip change. The number of times of detecting abnormality only when it becomes more than the set number, disconnection of the stepper motor, is characterized by detecting the failure of the ground fault Te (claim 1).

Further, the failure detection method of the vehicle motor of the present invention, first the abnormality detection signal, which changes the abnormality detection level from the normal detection level by abnormality of the stator coil voltage based on disconnection of the idle speed control stepper motor Error flag and a second error flag that changes from the normal detection level to the abnormality detection level due to an abnormality in the stator coil voltage based on the ground fault of the stepper motor. When each of the flags reaches the abnormality detection level, the stepper motor is forcibly driven in the same rotation direction until the excitation pattern of the stepper motor changes once (Claim 2).

Next, the on-vehicle motor failure detection apparatus according to the present invention is an idle speed of a vehicle that is excited and driven by a two-phase bipolar drive system based on an opening / closing command for opening / closing a flow control valve to set the engine speed to a target speed. When the abnormality detection signal that changes from the normal detection level to the abnormality detection level due to an abnormality in the stator coil voltage of the control stepper motor becomes the abnormality detection level, the opening / closing command is changed until the excitation pattern of the stepper motor changes once. Regardless of whether the stepper motor is forcibly driven in the same rotational direction, and each time the stepper motor advances one step while the excitation pattern changes by one cycle by the forcible driving, the abnormality detection signal is If there is an abnormality detection level, an abnormality detection number counting means for counting up the number of abnormality detections by 1, and the excitation pattern Only when the number of times of detecting abnormality by the round change of emission is equal to or more than the set number of times, it is characterized by comprising a failure detection output means for generating a detection output of the fault (claim 3).

Further, the failure detection device of the in-vehicle motor of the present invention, first the abnormality detection signal, which changes the abnormality detection level from the normal detection level by abnormality of the stator coil voltage based on disconnection of the idle speed control stepper motor Error flag and a second error flag signal that changes from the normal detection level to the abnormal detection level due to an abnormality in the stator coil voltage based on the ground fault of the stepper motor. Output from the first and second error flag terminals of the stepper motor driver integrated circuit forming the drive unit of the speed control stepper motor, respectively, and both the error flags of the error flag terminals are at the abnormality detection level. when, the forced drive means, the excitation pattern of the stepper motor changes round In which an also characterized that it has to be forcibly drive the stepper motor in the same rotational direction (claim 4).

According to the first and third aspects of the present invention, when the abnormality detection signal reaches the abnormality detection level, the ISC stepper motor controls the flow rate so that the engine rotation speed becomes the target rotation speed until the excitation pattern changes once. The valve is forcibly driven in the same rotational direction regardless of the opening / closing command for controlling the opening / closing of the valve . During this forcible driving, the number of times that the abnormality detection signal becomes the abnormality detection level is counted for each step of the stepper motor. The failure can be detected only when the count result is equal to or greater than the set number of times and the abnormality detection signal is at an abnormality detection level due to a stepper motor disconnection or a ground fault.

Therefore, when the abnormality detection signal changes to the abnormality detection level, the idle speed control stepper motor rotates in the same direction and its excitation pattern changes in a short time. Misdetection can be prevented , and disconnection and ground fault can be reliably detected. At this time, even if the stepping motor for idle speed control rotates in one direction by the number of steps in which the excitation pattern changes once, since the period is short, the change in the engine speed is very small and the driver feels the change. There will be no problems in terms of driving safety.

According to the second and fourth aspects of the present invention, the abnormality detection signal includes a first error flag that changes from a normal detection level to an abnormality detection level due to an abnormality in the stator coil voltage based on the disconnection of the ISC stepper motor. , Comprising a 2-bit signal with a second error flag that changes from the normal detection level to the abnormality detection level due to an abnormality in the stator coil voltage based on the ground fault of the stepper motor. based disconnection of the stepper motor in the same manner as in the configuration of claim 1, 3, can be detected reliably without false detection failures ground, both error flag, 2-phase Suteppamo Tado of the model number TLE4729G The stepper motor is formed by a 2-bit error flag of the driver IC that forms the drive unit of the stepper motor such as the driver IC5. It is possible to detect a disconnection, to ensure the failure of the ground fault.

  Next, in order to describe the present invention in more detail, an embodiment thereof will be described in detail with reference to FIGS.

  1 is a block diagram, FIG. 2 is a flowchart for explaining the operation of FIG. 1, FIG. 3 is a timing chart for explaining the operation when the disconnection of FIG. 1 occurs, and FIG. 4 is a ground fault of FIG. FIG. 9 is a timing chart for explaining the operation, and in these drawings, the same reference numerals as those in FIGS. 5 to 8 denote the same or corresponding elements.

  In this embodiment, since the ISC stepper motor 2 mounted on the vehicle 1 is driven by the two-phase stepper motor motor driver IC5 of the model number TLE4729G in the two-phase bipolar drive system, as shown in FIG. The control unit 3 is provided with a drive unit 4b formed by the driver IC 5 instead of the drive unit 4a of FIG.

  Further, the first and second error flags ERR1 and ERR2 of the error flag terminals e1 and e2 of the driver IC 5 are supplied to the failure detection processing unit 6 formed by the microcomputer of the control unit 3.

  The detection processing unit 6 operates as shown in steps Q1 to Q15 in FIG. 2 by software processing of a computer, and includes the following means (1) to (3).

(1) Forced drive means This means that the error flag ERR1 is changed from a high level (normal detection level) H to a low level (abnormal) due to an abnormality in the stator coil voltage (disappearance of the back electromotive voltage) based on the disconnection of the ISC stepper motor 2. The error flag ERR2 is changed from the high level (normal detection level) H to the low level due to abnormality (voltage loss) of the stator coil voltage based on the ground fault of the ISC stepper motor 2 including the harness when the detection level is changed to L. When (abnormality detection level) changes to L, the driver IC 5 is instructed to forcibly drive the ISC stepper motor 2 in the same rotation direction, and the ISC stepper motor 2 is rotated through the driver IC 5 until the excitation pattern changes once. Force drive in the direction.

(2) Abnormality detection frequency counting means This means that the ISC stepper motor 2 is forcibly driven in the same rotational direction by the forcible driving means, and the excitation signal of the ISC stepper motor 2 is changed once, so that the control signal of the driver IC 5 Each time the step of the ISC stepper motor 2 is detected, if the error flags ERR1 and ERR2 that are the same as when forced driving is started are at a low level L, they are held in a rewritable storage means such as a memory or a counter. Increase the number of abnormal detections by one. This abnormality detection count is initially set to 1 when forced driving is started.

(3) Failure detection output means When the excitation pattern is changed once by the forced drive, this means is only used when the number of times of abnormality detection of the storage means is equal to or greater than the set number due to this change in the round. Detection output ERR of disconnection of stepper motor 2 and fault of ground fault is generated.

  Next, the operation of FIG. 1 will be described with reference to FIG.

First, the ISC stepper motor 2 advances one step in one direction or the other direction every τ / 2, specifically, for example, every 5 ms as described above based on the flow control valve opening / closing request or the like.

  Therefore, after the engine of the vehicle 1 is started, the detection processing unit 6 usually only monitors the power supply voltage of the vehicle 1 every 5 ms by the loop of steps Q1 to Q4 in FIG. Do.

  If the power supply voltage becomes abnormal, the ISC stepper motor 2 is prohibited from being driven in step Q5 in FIG. 2 to prevent malfunction and erroneous control, and the motor 2 is held in a stopped state.

  Next, when a disconnection occurs at tα as shown in FIG. 3, as shown in FIG. 3A, the back electromotive voltage P does not occur in the voltage Va of the coil 2a, and the circuit shown in FIG. As described above, the error flag ERR1 changes to the low level L. 3B shows the voltage Vb of the coil 2b, and FIG. 3D shows the error flag ERR2.

Based on the change in the low level L, the detection processing unit 6 detects an abnormality in the excitation voltage of the ISC stepper motor 2 in step Q3 of FIG. 2, and proceeds to step Q6 to determine the abnormality detection count D and the forced step number R. 1 to initially set, it instructs the excitation drive one step increment of the ISC stepper motor 2 to direction of rotation which is the same rotational direction or setting the ever driver IC5 in step Q7.

  The detection processing unit 6 also stores that abnormality detection has occurred based on the low level L of the error flag ERR1.

  Then, when the ISC stepper motor 2 advances by one step, for example, from the step S1 of the excitation pattern “1” in which the abnormality of FIG. 3 occurs to the step S2 of the excitation pattern “2”, FIG. In step Q7, it is determined whether or not the error flag ERR1 at that time is at the low level L. If the error flag ERR1 is at the low level L due to the same abnormality, the abnormality detection count D is set to 1 by steps Q8 and Q9. Count up.

Furthermore, until the excitation pattern of the ISC stepper motor 2 returns to “1” through “2”, “3”, “4” by the forcible driving and changes once, that is, the forced step number until R reaches 5, the process returns to step Q7 via step Q10~Q13 from step Q9 of FIG. 2, and counts up the forced walking radix R, after confirming the normal power supply voltage, to the same direction of rotation The ISC stepper motor 2 is instructed to perform excitation driving for one step.

  3 is repeated from step Q7 to step Q7 through steps Q8 to Q13, the forced step number R reaches 5, the excitation pattern of the ISC stepper motor 2 changes once, and the step state of FIG. The ISC stepper motor 2 is stepped step by step from S1 to the stepping state S5 through the stepping states S2, S3, and S4.

  Meanwhile, every time the ISC stepper motor 2 advances one step, it is determined whether or not the error flag ERR1 is at the low level L. If the error flag ERR1 is at the low level L due to the same abnormality, the abnormality detection count D is calculated. Count up by one.

  When the forced step number R reaches 5 and the excitation pattern of the ISC stepper motor 2 changes once, the process proceeds from step Q10 to step Q14 in FIG. 2 to determine whether or not the abnormality detection count D is equal to or greater than the set count. Determine.

  By the way, the set number of times of abnormality detection D is determined in consideration of the number of steps at which the error flags ERR1 and ERR2 become low level L while the excitation pattern of the ISC stepper motor 2 changes once, and when disconnection occurs. 6 and 3 (c), the error flag ERR1 is set to the low level L for the entire period of the step number 5, but when a ground fault occurs, the error flag ERR1 is set to (c) in FIGS. As will be apparent from the above, since the error flag ERR2 becomes the low level L only for the period of the step number 3, in this embodiment, erroneous detection by the instantaneous low level L of the error flags ERR1 and ERR2 due to disturbance such as noise is performed. In order to prevent it reliably, the set number of times is set to 3.

  If the disconnection occurs, the abnormality detection count D becomes 5, so the process proceeds to step Q15 in FIG. 2. At this time, the occurrence of the disconnection is detected, and the time as shown in FIG. A failure detection output ERR is generated at tα *, and based on this detection output ERR, the process proceeds from step Q15 to step Q5, and the drive of the ISC stepper motor 2 is prohibited and the ISC stepper is prohibited in order to prevent malfunction and control. The motor 2 is held in its rotating state. Further, an idle failure is reported in the vehicle based on the detection output ERR.

  Next, when the ground fault of the coil 2a occurs at tβ as shown in FIG. 4, the voltage Va of the coil 2a in FIG. 4A disappears, and the error flag ERR2 in FIG. To change. 4B shows the voltage Vb of the coil 2b, and FIG. 4C shows the error flag ERR1.

Then, based on the change in the low level L of the error flag ERR2, the detection processing unit 6 operates in the same manner as when a disconnection occurs, and initially sets the abnormality detection count D and the forced step count R to 1 in step Q6 of FIG. set commands the excitation drive one step increment of the ISC stepper motor 2 to direction of rotation which is the same rotational direction or setting the ever driver IC5 in step Q7.

  Then, the ISC stepper motor 2 advances by one step, and as shown in FIG. 4, from the step state S1 ′ of the excitation pattern “2” where the abnormality has occurred to the step state S2 ′ of the excitation pattern “2”. Then, as described above, the error flag ERR2 returns to the high level H, and then, when the ISC stepper motor 2 advances by 3 steps and becomes the step S4 ′ of the excitation pattern “1” in FIG. ERR2 becomes low level L again.

  For this reason, the excitation pattern of the ISC stepper motor 2 changes from “2” to “2” through “3”, “4”, “1” by the forcible driving and changes in one round, and the forced step number R becomes 5 2, the abnormality detection count D becomes 3, the process proceeds to step Q15 in FIG. 2 to detect the occurrence of a ground fault, and as shown in FIG. 4E, the failure detection output ERR at time tβ *. Based on this detection output ERR, the drive of the ISC stepper motor 2 is prohibited and the ISC stepper motor 2 is held in its rotating state, and an idle failure is reported in the vehicle, as in the case where the disconnection occurs.

  When the error flags ERR1 and ERR2 change to the low level L, the disconnection and the ground fault are not detected immediately, but the excitation pattern is changed once to forcibly move the ISC stepper motor 2 in the same direction. In order to detect a disconnection or ground fault from the step number of the ISC stepper motor 2 in which the error flag ERR1, ERR2 is at a low level L during the rotation of the decimal number, in particular, the level change due to the excitation pattern of the error flag ERR2, Distinguishes from instantaneous level changes due to disturbances such as noise, prevents erroneous detection based on instantaneous low level L changes of error flags ERR1 and ERR2, and reliably detects disconnection and ground faults it can.

  At this time, the ISC stepper motor 2 rotates in one direction by the number of steps in which the excitation pattern changes once by forced driving, but the period is extremely short, and depending on this degree of rotation of the ISC stepper motor 2, the rotation of the engine The change in the number is so small that the driver does not feel the change, and no problem occurs in terms of driving safety.

  Therefore, the driver 4b of the ISC stepper motor 2 is formed by the driver IC 5, and the error flags ERR1 and ERR2 are used to prevent disconnection and ground faults of the ISC stepper motor 2 including the harnesses from being detected very quickly. And can be reliably detected.

  Note that the number of magnetic poles and the like of the ISC stepper motor 2 may be whatever, and it goes without saying that the processing procedure of the detection processing unit 6 may be different from that shown in FIG.

The present invention is not limited to the above-described embodiment, and various modifications other than those described above can be made without departing from the spirit thereof.
The drive unit 4b is formed by a two-phase stepper motor driver IC different from the driver IC 5, and the first and second error flags output from the first and second error flag terminals are errors due to disconnection and ground fault. It may change in a different pattern from the flags ERR1 and ERR2.

  Also, the abnormality detection signal does not have to be another 2-bit signal of disconnection or ground fault such as the error flags ERR1 and ERR2, but one bit that changes the abnormality detection level from the normal detection level due to either disconnection or ground fault. Or it may be a multi-bit signal.

  By the way, the failure detection output ERR based on the number of abnormality detections of the error flag ERR1 and the failure detection output ERR based on the number of abnormality detections of the error flag ERR2 are differentiated to detect a disconnection failure and a ground fault failure. However, the present invention can also be applied to the case where failure notification or the like is performed in detail.

It is a block diagram of one embodiment. It is a flowchart for operation | movement description of FIG. 2 is a timing chart for explaining operations when the disconnection in FIG. 1 occurs. It is a timing chart for operation | movement description when the ground fault of FIG. 1 generate | occur | produces. FIG. 2 is a block diagram of a general control unit that drives a two-phase bipolar drive for an idle speed control stepper motor mounted on a vehicle. It is a timing chart for operation | movement explanation when the disconnection of a prior art example generate | occur | produces. It is a timing chart for operation | movement explanation when the ground fault of a prior art example generate | occur | produces. FIG. 6 is a block diagram of a driver integrated circuit that forms the drive unit of FIG. 5.

Explanation of symbols

DESCRIPTION OF SYMBOLS 1 Vehicle 2 ISC stepper motor 4b Drive part 5 2 phase stepper motor driver IC
6 Detection processing section

Claims (4)

Normal detection based on abnormality of stator coil voltage of stepper motor for idle speed control of vehicle driven by two-phase bipolar drive system based on open / close command to control opening / closing of flow rate control valve to make engine speed target speed When the abnormality detection signal that changes from the level to the abnormality detection level becomes the abnormality detection level, the stepper motor is forcibly driven in the same rotation direction regardless of the opening / closing command until the excitation pattern of the stepper motor changes once. ,
Each time the stepper motor advances by one step while the excitation pattern changes by one cycle by the forced driving, if the abnormality detection signal is the abnormality detection level, the number of times of abnormality detection is incremented by one,
A fault detection method for an on-vehicle motor, wherein a disconnection of the stepper motor or a fault in a ground fault is detected only when the number of times of abnormality detection is equal to or more than a set number due to a round change of the excitation pattern. The abnormality detection signal, a first error flag to be changed to the abnormality detection level from the normal detection level by abnormality of the stator coil voltage based on disconnection of the idle speed control stepper motor, based on the ground fault of the stepper motor A 2-bit signal with a second error flag that changes from the normal detection level to the abnormality detection level due to an abnormality in the stator coil voltage;
2. The vehicle-mounted device according to claim 1, wherein when each of the error flags reaches the abnormality detection level, the stepper motor is forcibly driven in the same rotational direction until the excitation pattern of the stepper motor changes once. Motor failure detection method. Normal detection based on abnormality of stator coil voltage of stepper motor for idle speed control of vehicle driven by two-phase bipolar drive system based on open / close command to control opening / closing of flow rate control valve to make engine speed target speed When the abnormality detection signal that changes from the level to the abnormality detection level becomes the abnormality detection level, the stepper motor is forcibly driven in the same rotation direction regardless of the opening / closing command until the excitation pattern of the stepper motor changes once. Forced drive means,
When the stepper motor advances by one step while the excitation pattern changes by one cycle by the forced driving, an abnormality detection number counting means for incrementing the number of times of abnormality detection if the abnormality detection signal is the abnormality detection level. When,
A failure detection apparatus for an on-vehicle motor, comprising failure detection output means for generating the failure detection output only when the number of times of abnormality detection is equal to or greater than a set number due to a round change of the excitation pattern. The abnormality detection signal, a first error flag to be changed to the abnormality detection level from the normal detection level by abnormality of the stator coil voltage based on disconnection of the idle speed control stepper motor, based on the ground fault of the stepper motor A signal of a second error flag that changes from the normal detection level to the abnormality detection level due to an abnormality in the stator coil voltage;
The both error flags are respectively output from the first and second error flag terminals of the stepper motor driver integrated circuit forming the drive unit of the idle speed control stepper motor,
Wherein when each of the two error flags both error flag pin becomes the abnormality detection level, the forced drive means, the excitation pattern of the stepper motor to force driven in the same rotational direction the stepper motor to vary round The failure detection apparatus for an on-vehicle motor according to claim 3, wherein the apparatus is configured as described above.

Images