JP5594036B2 - Starter abnormality diagnosis device - Google Patents

Description

  The present invention includes a starter configured to have a brush that is pressed toward the commutator and contacts the commutator, and a process of automatically stopping the engine. After the process of automatically stopping, cranking by the starter is performed. The present invention relates to an abnormality diagnosis device for a starter applied to a vehicle including means for performing a process of performing and restarting the engine.

  Conventionally, so-called idle stop control is performed in which a process for automatically stopping the engine when a predetermined stop condition is satisfied, and then a process for restarting the engine by performing cranking by a starter when the predetermined restart condition is satisfied. Processing is known. Here, in a vehicle in which the idle stop control process is performed, the starter drive frequency increases to restart the engine, so that the starter deterioration may be accelerated, such as accelerated wear of the starter brush.

  Therefore, as can be seen in Patent Document 1 below, there is also disclosed a technique for stopping the process of automatically stopping the engine when it is determined that the integrated value of the starter driving time is equal to or greater than a predetermined determination value. As a result, the starter drive by the idle stop control can be stopped before it is assumed that the starter is deteriorated, and it is possible to avoid a situation in which the starter is rapidly deteriorated. In addition, as a technique regarding the starter, for example, there is one disclosed in Patent Document 2 below.

JP 2001-263210 A JP 2003-206839 A

  By the way, in order to grasp the presence or absence of deterioration of the starter, it is required to properly grasp the presence or absence of deterioration of the starter brush. However, in the technology described in Patent Document 1, since the starter drive time is integrated using the integrated value of the starter drive time, the drive time is determined to be equal to or greater than a predetermined determination value depending on the use mode of the starter. There is a risk that the accuracy of grasping the presence or absence of deterioration of the brush may be lowered, for example, the brush is excessively worn before becoming.

  The present invention has been made to solve the above-described problems, and an object of the present invention is to provide an abnormality diagnosis device for a starter that can accurately diagnose the presence or absence of deterioration of a brush provided in the starter.

  Hereinafter, means for solving the above-described problems and the operation and effects thereof will be described.

According to a first aspect of the present invention, there is provided a starter configured to have a brush that is pressed toward the commutator and comes into contact with the commutator, and a process for automatically stopping the engine. The brush is applied to a vehicle having a means for performing a process of restarting the engine by ranking, and the brush has a surface spaced from the surface that contacts the commutator to the brush side of the brush with respect to the commutator. The exposure means has a function of making the amount of fluctuation of the current flowing through the brush different from that before the exposure. The detecting means detects the current flowing through the brush or the value of a parameter correlated therewith, and the clutch. Diagnosis for performing a process of diagnosing the presence or absence of deterioration of the brush based on the amount of fluctuation of the detection value of the detection means at the time of ranking Characterized in that it comprises a stage.

  The brush in the above invention has a function of making the fluctuation amount of the current flowing in the brush different from that before the exposure of the separated surface by exposing the surface of the brush which is separated from the surface in contact with the commutator to the brush side. It has. In other words, when the wear of the brush progresses and the separated surface is exposed to the commutator, the amount of fluctuation of the current flowing through the brush changes during cranking. For this reason, in the said invention, the presence or absence of deterioration of a brush can be diagnosed with high precision based on the fluctuation amount of the detection value of the detection means which detects the electric current which flows through a brush, or the value of the parameter which has a correlation with this.

According to a second aspect of the present invention, in the first aspect of the invention, in the brush, the material or shape of a layer separated from the surface of the brush that contacts the commutator toward the brush is different from the material or shape of other portions. It is characterized by comprising.

  If the material of the brush is different, the amount of current flowing through the brush changes due to a change in the degree of heat generation on the contact surface due to sliding between the commutator and the brush. In addition, if the shape of the contact surface between the commutator and the brush is different, the degree of heat generation on the contact surface due to sliding between the commutator and the brush, the manner of occurrence of sparks, etc. will change, and the current flowing through the brush The amount of change changes. In view of this point, in the above invention, the brush is provided with the above-described aspect, so that the brush has a function of making the amount of fluctuation of the current flowing through the brush different. For this reason, when the wear of the brush progresses and the separated layer is exposed and contacted with the commutator, the fluctuation amount of the current flowing through the brush changes. Thereby, the difference in the fluctuation amount of the current flowing through the brush can be appropriately caused as the brush deteriorates.

According to a third aspect of the present invention, in the first or second aspect of the invention, when the diagnosis unit determines that the restarting process has been performed a plurality of times after the engine is started by operating an ignition key of a driver. The diagnosis process is performed.

  An oxide film may be generated on the brush surface due to a long elapsed time from when the engine is stopped by the operation of the ignition key until the engine is started by the operation of this key. When an oxide film is formed on the brush surface, the amount of fluctuation in the current flowing through the brush changes during cranking due to the increase in the electrical resistance of the brush. There is a risk that the diagnostic accuracy of the presence or absence will decrease. When the process of restarting the engine is performed here, the oxide film on the brush surface is removed by sliding between the commutator and the brush. If the number of executions of the restarting process is large, the degree of removal of the oxide film increases. In view of this point, in the above-described invention, when it is determined that the process of restarting the engine has been performed a plurality of times, the process of diagnosing is performed. Thereby, the fall of the diagnostic precision about the deterioration of the brush resulting from the said oxide film can be suppressed suitably.

In a fourth aspect based on any one of the first to third aspects, the diagnosis means is the detection means when the temperature of the contact surface between the brush and the commutator is assumed to be a reference temperature. The diagnosis processing is performed based on the fluctuation amount of the detected value.

  Due to the change in the temperature of the contact surface between the brush and the commutator, the amount of fluctuation of the current flowing through the brush can change. In this case, it may not be possible to appropriately diagnose whether or not the brush has deteriorated based on the fluctuation amount of the detected value. Particularly in a vehicle in which idle stop control is performed, the temperature of the contact surface at the time of detection by the detection means is likely to vary depending on the use mode of the starter by this control, and the decrease in diagnostic accuracy as to whether the brush has deteriorated is significant. There is a risk.

  In this regard, in the above invention, the diagnosis process is performed based on the amount of change in the detected value when the temperature of the contact surface between the brush and the commutator is assumed to be a reference temperature. For this reason, the fall of the diagnostic accuracy resulting from the change of the temperature of the said contact surface can be suppressed suitably.

In a fifth invention, in any one of the first to fourth inventions, when the diagnosis means diagnoses that the brush is deteriorated, a process for notifying the driver of the fact and a process for automatically stopping the brush It further comprises processing means for performing at least one of the processes for prohibiting.

  In the said invention, the process of the said aspect is performed by a process means, and the situation where a starter is used continuously in the state which the brush deteriorated can be avoided appropriately.

The system block diagram concerning one Embodiment. The figure which shows the structure of the brush concerning one Embodiment. The figure which shows the measurement result of the battery voltage at the time of making the brush material concerning one Embodiment differ. The figure which shows the outline | summary of the diagnostic method of the presence or absence of the brush deterioration concerning one Embodiment. The figure which shows the outline of the brush shaping | molding process concerning one Embodiment. The flowchart which shows the procedure of the brush deterioration diagnostic process concerning one Embodiment. The time chart which shows an example of the brush deterioration diagnostic process concerning one Embodiment. (A) is a figure which shows the structure of the brush concerning other embodiment. (B) is AA sectional drawing of a brush.

  Hereinafter, an embodiment in which a diagnostic device according to the present invention is applied to a vehicle including an engine and a starter will be described with reference to the drawings.

  FIG. 1 shows a system configuration according to the present embodiment.

  As shown in the figure, the starter 10 includes a pinion 12, a switch unit (not shown) for pushing out the pinion 12, a motor unit 14 for rotating the pinion 12, and the like.

  The motor unit 14 includes an armature (armature 16), a brush 18, a field coil 20 for generating a magnetic field (field magnetic field) for the armature 16, and the like. The armature 16 includes a rotating shaft 22, a commutator (commutator 24), an armature core (not shown), and the like. An armature coil is provided in a slot formed on the outer periphery of the armature core. In this embodiment, a plurality of pairs (for example, two pairs) of brushes 18 are provided, but only one pair is shown in the figure.

  The commutator 24 is a cylindrical member that is fixed to one end of the rotating shaft 22 while being insulated from the shaft. The commutator 24 is divided into a plurality of segments 24 a formed on the outer periphery thereof, and an insulating portion 24 b made of a resin that insulates each segment. It is configured with. The commutator 24 has a function of rectifying the current flowing through the armature coil so that the polarity of the magnetic field generated by the armature 16 is always constant with respect to the field magnetic field.

  The brush 18 is pressed against the commutator 24 by a spring 26 and is in contact with the commutator 24, and is a member for supplying the power of the battery 28 to the armature coil of the armature 16. Specifically, the brush 18 is a member having a substantially rectangular parallelepiped shape, and has conductivity made of carbon (graphite) and metal (copper). The brushes 18 have the same shape, and the force with which the brush 18 is pressed against the commutator 24 by the spring 26 is the same. The brush 18 is provided with a lead wire 29 (pigtail).

  A starter switch 30 and a relay 32 are provided between the motor unit 14 and the battery 28 for switching power supply to the motor unit 14 or stopping of power supply. The starter switch 30 is switched on and off by a turning operation of the ignition key 34 of the driver. The member operated by the driver to turn on / off the starter switch 30 is not limited to a rotary operation type such as the ignition key 34, and may be a button type operation member, for example.

  In such a configuration, when the starter switch 30 and the relay 32 are turned on, current flows to the armature coil in the armature 16 via the lead wire 29, the brush 18 and the commutator 24 using the battery 28 as a power supply source. The current that flows through the armature coil flows through the commutator 24 to the field coil 20. As a result, the magnetic field formed by the armature coil and the field magnetic field formed by the field coil 20 are linked to each other, so that a rotational force is applied to the rotating shaft 22 and the pinion 12 is rotationally driven. Then, when the pinion 12 is rotationally driven by the motor unit 14 in a situation where the pinion 12 is pushed toward the ring gear 40 mechanically connected to the crankshaft 38 of the engine 36, the pinion 12 meshes with the ring gear 40. Thus, initial rotation is applied to the crankshaft 38 (cranking is performed). When the relay 32 and the like are turned off and the power supply from the battery 28 to the motor unit 14 is interrupted, the meshing between the pinion 12 and the ring gear 40 is released.

  An electronic control device (hereinafter referred to as ECU 42) that operates the starter 10 is mainly composed of a microcomputer including a known CPU, ROM, RAM, and the like. The ECU 42 receives output signals from a voltage sensor 44 that detects the voltage of the battery 28, a current sensor 46 that detects current supplied to the starter 10 (flowing to the brush 18), and the like. The ECU 42 executes the various control programs in accordance with the input, thereby performing a drive control process of the starter 10 by an energization operation of the relay 32 and the like, an idle stop control process, and the like.

  The idle stop control process performs a process of automatically stopping the engine 36 by stopping fuel injection from a fuel injection valve (not shown) when a predetermined stop condition is satisfied, and then a predetermined restart condition is satisfied. This is a process for restarting the engine 36 by the drive control of the starter 10 or the like.

  Next, a diagnosis method for the presence or absence of brush deterioration according to the present embodiment will be described with reference to FIGS. 2 and 4, the commutator 24 does not show the segment 24a and the insulating portion 24b, and the brush 18 shows only one of the plurality of brushes 18.

  In the brush 18 according to the present embodiment, the material of the layer (hereinafter referred to as the wear detecting portion 18a) separated from the surface (contact surface S) in contact with the commutator 24 in the brush 18 toward the brush 18 side is the other portion (hereinafter referred to as normal). It shall be comprised so that it may differ from the material of the part 18b). Specifically, the ratio of copper to carbon is lower in the wear detection portion 18a than in the normal portion 18b. And the presence or absence of deterioration of the brush 18 is diagnosed based on the fluctuation amount of the battery voltage detected by the voltage sensor 44 at the time of cranking. This diagnosis method is based on the fact that when the material of the brush 18 is different, the degree of heat generation of the contact surface S accompanying the sliding of the commutator 24 and the brush 18 due to the rotation of the rotating shaft 22 changes. This is based on the fact that the amount of fluctuation of the current flowing through 18 (starter current) changes, and the amount of fluctuation of the battery voltage changes accordingly. Hereinafter, the change in the amount of change in the starter current and the battery voltage due to the difference in the brush material will be described in detail with reference to FIG. 3, and then a method for diagnosing the presence or absence of brush deterioration will be described in detail with reference to FIG.

  FIG. 3 shows measurement results of the starter current and the battery voltage when the brush materials are different. Specifically, FIG. 3A shows the measurement results of the starter current and battery voltage when a brush having a high copper to carbon ratio (corresponding to the normal portion 18b) is used, and FIG. The measurement result in the case of using a brush (corresponding to the wear detection unit 18a) having a low copper ratio is shown.

  As shown in FIG. 3A, the starter current waveform includes ripples. That is, the starter current varies. This is because, when the commutator 24 and the brush 18 slide, a spark is generated when the contact state of the brush 18 changes from the segment 24a to the insulating portion 24b. When the starter current varies, the battery voltage varies.

  On the other hand, as shown in FIG. 3B, when a brush having a low copper to carbon ratio is used, the ripple included in the waveform of the starter current increases during cranking. That is, the amount of change in the starter current increases. This is due to an increase in the amount of heat generated by sliding between the commutator 24 and the brush 18 when the ratio of copper to carbon is lowered. As the starter current fluctuation amount increases, the battery voltage fluctuation amount increases.

  By utilizing the change in the amount of change in battery voltage based on the difference in brush material described above, it is possible to diagnose the presence or absence of deterioration of the brush 18. Specifically, as shown in FIG. 4, the normal portion 18 b of the brush 18 comes into contact with the commutator 24 at the normal time when the wear of the brush 18 is not progressing. On the other hand, when the wear of the brush 18 progresses and the wear detector 18a of the brush 18 comes into contact with the commutator 24, the amount of battery voltage fluctuation during cranking increases. That is, in this embodiment, when it is determined that the battery voltage fluctuation amount ΔV is equal to or less than the specified value Vα, it is diagnosed that the brush 18 has not deteriorated, and it is determined that the battery voltage fluctuation amount ΔV exceeds the specified value Vα. If so, it is diagnosed that the brush 18 has deteriorated. Here, the fluctuation amount ΔV of the battery voltage may be calculated as a value obtained by subtracting the minimum value from the maximum value of the battery voltage detected in a predetermined period at the time of cranking, for example.

  The specified value Vα is a battery voltage assumed when the normal part 18b contacts the commutator 24 under the condition that the temperature around the starter 10 (engine room temperature) is set to a reference temperature (reference temperature). It is set as a value slightly larger than the fluctuation amount ΔV. Here, when setting the specified value Vα, the temperature-related specification is provided in order to determine a diagnostic criterion for the deterioration of the brush 18. That is, if the temperature around the starter 10 is different and the temperature of the contact surface between the brush 18 and the commutator 24 is different, the amount of change in the starter current and the amount of change in the battery voltage change. For this reason, in setting the prescribed value Vα to be compared with the fluctuation amount, a diagnostic criterion for determining whether or not the brush 18 has deteriorated is established by providing a regulation relating to the temperature. The reference temperature may be set to a temperature around the starter 10 when the engine 36 is warmed up, for example.

  Incidentally, the thickness of the wear detecting portion 18a is determined from the viewpoint that the contact surface between the brush 18 and the commutator 24 is returned to the normal portion 18b as soon as possible after the wear detecting portion 18a is exposed to the commutator 24. (For example, 0.1 to 0.5 mm). That is, the wear detection part 18a is thinner than the normal part 18b. This is for returning the characteristics of the starter 10 to the normal characteristics as soon as possible because the characteristics of the starter 10 deviate from the normal characteristics when the wear detector 18a is exposed to the commutator 24.

  Next, the molding process of the brush 18 according to the present embodiment will be described with reference to FIG.

  First, an apparatus used in the molding process of the brush 18 will be described.

  The above apparatus includes a die 50, an upper punch 52, a lower punch 54, a high copper side feeder 56 for filling a raw material powder (high copper molding powder) having a high copper ratio with respect to carbon, and copper with respect to carbon. Is provided with a low copper side feeder 58 for filling raw material powder (low copper molding powder) with a low ratio. Specifically, a molding space V for pressing the raw material powder of the brush 18 is formed by the die 50, the lower punch 54, and the like.

  The lower punch 54 is arranged to be movable in the vertical (up and down) direction below the molding space V, and the upper punch 52 is arranged to be movable in the vertical (up and down) direction above the molding space V. ing. Moreover, each of the high copper side feeder 56 and the low copper side feeder 58 is arrange | positioned so that the upper part of the die | dye 50 can be moved to a horizontal (left-right) direction. The upper punch 52 is provided with a through hole for inserting the lead wire 29 into the raw material powder in the molding space V.

  Next, the molding process of the brush 18 according to the present embodiment will be described in detail.

  First, in step 1, the high copper side feeder 56 is moved rightward so as to be positioned above the molding space V, and then the high copper side feeder 56 is filled with the high copper molding powder in the molding space V.

  Next, in step 2, the molding space V is filled with the low copper molding powder by the low copper side feeder 58. Specifically, the high copper side feeder 56 is moved leftward from the upper part of the molding space V, and the low copper side feeder 58 is moved leftward so as to be positioned above the molding space V. At this time, the lower punch 54 is moved downward to ensure a molding space V for filling the low copper molding powder. Then, the low copper molding powder is filled into the molding space V by the low copper side feeder 58. That is, in the molding space V, the low copper molding powder is filled into the upper part of the high copper molding powder.

  In the subsequent step 3, the high copper molding powder is filled again into the molding space V by the high copper side feeder 56. Specifically, first, the low copper side feeder 58 is moved to the right from the upper part of the molding space V, and the high copper side feeder 56 is moved to the right to be positioned on the upper part of the molding space V. At this time, the lower punch 54 is moved downward in order to secure a molding space V for filling the high copper molding powder. Then, the high copper molding powder is filled into the molding space V by the high copper side feeder 56. That is, in the molding space V, the high copper molding powder is filled in layers on the top of the low copper molding powder.

  In the subsequent step 4, the raw material powder filled in the molding space V is pressure-molded. Specifically, after the high copper side feeder 56 is moved leftward from the upper part of the molding space V, the upper punch 52 is moved downward and the lower punch 54 is moved upward. Thereby, the raw material powder in the molding space V is pressure-molded. As the upper punch 52 moves downward, the lead wire 29 is inserted into the raw material powder in the molding space V through the through-hole formed in the upper punch 52.

  In the subsequent step 5, the lead wire 29 extending from the pressure-molded raw material powder is cut by a cutter 60 with an appropriate length.

  In step 6, the pressure-molded raw material powder is taken out by raising the lower punch 54. In addition, the raw material powder pressure-molded after that passes through a predetermined baking process and a cutting process, and the brush 18 is completed.

  FIG. 6 shows the procedure of brush deterioration diagnosis processing according to the present embodiment. This process is executed by the ECU 42 at a predetermined cycle, for example.

  In this series of processing, first, in step S10, it is determined whether or not the value of the brush deterioration diagnosis flag F is set to “0”. This process is for determining whether or not the brush 18 has already deteriorated. Here, the brush deterioration diagnosis flag F indicates that the brush 18 is deteriorated by “1”, and indicates that it is not deteriorated by “0”. The value of the diagnostic flag F is stored in a nonvolatile memory (for example, EEPROM) of the ECU 42, and its initial value is set to “0”.

  If it is determined in step S10 that the brush deterioration diagnosis flag F is “0”, it is determined that the brush 18 has not deteriorated, and automatic stop of the engine 36 is permitted in step S12. This process is for avoiding a situation where the engine 36 cannot be restarted. That is, when the engine 36 is automatically stopped under the condition where the brush 18 is deteriorated, when the restart condition is satisfied after that, the starter 10 cannot properly perform cranking, and the engine 36 is restarted. There is a risk that it will not be possible. For this reason, by providing a process for permitting automatic stop, it is possible to avoid a situation in which the engine 36 cannot be restarted.

  In a succeeding step S14, it is determined whether or not a stop condition for the engine 36 is satisfied. If it is once determined that the stop condition is satisfied in this step, an affirmative determination is made in this step until the restart of the engine 36 is completed.

  When it is determined in step S14 that the stop condition is satisfied, the process proceeds to step S16, and it is determined whether or not the restart condition of the engine 36 is satisfied.

  If it is determined in step S16 that the restart condition is satisfied, the process proceeds to step S18, and drive control processing of the starter 10 is performed to perform cranking. That is, power supply from the battery 28 to the starter 10 is started.

  In a succeeding step S20, it is determined whether or not a diagnosis execution condition for the brush deterioration diagnosis process is satisfied. In the present embodiment, the diagnosis execution condition is a condition that the logical product of the following conditions (A) to (C) is true. These conditions are for avoiding a decrease in diagnostic accuracy regarding the deterioration of the brush 18.

  (A) A condition that a first specified time TA (for example, 10 minutes) has elapsed since the engine 36 was initially started by operating the ignition key 34: The engine 36 was initially started by operating the ignition key 34. Then, the temperature around the starter 10 gradually rises and becomes substantially stable when the engine 36 is warmed up. Here, since the temperature around the starter 10 is different and the temperature of the contact surface between the brush 18 and the commutator 24 is changed, the amount of change in the starter current is changed, and the amount of change in the battery voltage is changed. For this reason, when the diagnosis process is executed in a situation where the temperature around the starter 10 is not stable after the engine 36 is started for the first time, the temperature at the time of detection of the battery voltage and the specified value Vα are calculated for the temperature of the contact surface. The temperature corresponding to the reference temperature at the time of setting may deviate greatly. In this case, for example, there is a risk that the presence or absence of deterioration of the brush 18 is erroneously diagnosed, for example, the brush 18 is diagnosed as having deteriorated even though it has not actually deteriorated. For this reason, by providing the condition (A), the detection value of the voltage sensor 44 under the situation where the temperature of the contact surface is assumed to be the reference temperature is used for diagnosis, and the diagnosis accuracy of the deterioration of the brush 18 is reduced. To avoid. The first specified time TA may be set, for example, by measuring in advance the time required for the engine 36 to be warmed up by experiments or the like.

  (B) A condition that the engine 36 is restarted a plurality of times (for example, five times) after the engine 36 is initially started by operating the ignition key 34: The engine 36 is stopped by operating the ignition key 34 An oxide film may be formed on the surface of the brush 18 due to a long elapsed time from when the ignition key 34 is operated until the engine 36 is first started. When an oxide film is generated on the surface of the brush 18, the amount of fluctuation of the battery voltage ΔV changes due to the amount of fluctuation of the starter current at the time of cranking due to an increase in the electrical resistance of the brush 18. Can do. In this case, there is a possibility that the diagnosis accuracy for the deterioration of the brush 18 based on the battery voltage fluctuation amount ΔV is lowered. Here, when cranking is performed by the process of restarting the engine 36, the oxide film on the surface of the brush 18 is removed by the sliding of the commutator 24. If the number of executions of the restarting process is large, the degree of removal of the oxide film increases. For this reason, by providing the condition (B), it is possible to avoid a decrease in diagnostic accuracy with respect to deterioration of the brush 18 due to the oxide film generated on the surface of the brush 18.

  (C) The condition that the second specified time TB has elapsed after the completion of the process of restarting the engine 36 a plurality of times (fifth time): Cranking is started by the process of restarting the engine 36 Then, the temperature of the contact surface between the brush 18 and the commutator 24 rises due to the sliding between the commutator 24 and the brush 18. After that, when the cranking is stopped by completing the restarting process, the temperature of the contact surface gradually decreases toward a temperature corresponding to the temperature around the starter 10. Here, depending on the elapsed time after the restart of the engine 36 is completed, the temperature of the contact surface at the time of detection of the battery voltage greatly deviates from the temperature corresponding to the reference temperature when the specified value Vα is set. As a result, there is a risk that the diagnostic accuracy of the deterioration of the brush 18 may be reduced. For this reason, by providing the condition (C), it is possible to avoid a decrease in diagnostic accuracy for the deterioration of the brush 18. The second specified time TB may be set, for example, by measuring in advance an experiment or the like the time required for the temperature of the contact surface that has risen due to cranking to fall to a temperature corresponding to the reference temperature. .

  If it is determined in step S20 that the diagnosis execution condition is satisfied, the process proceeds to step S22, and the battery voltage fluctuation amount ΔV is set to the specified value Vα in a situation where cranking is performed by the drive control process of the starter 10. It is judged whether it exceeds.

  If it is determined in step S22 that the battery voltage fluctuation amount ΔV exceeds the specified value Vα, the brush 18 is diagnosed as being deteriorated, and the value of the brush deterioration diagnosis flag F is set to “1” in step S24. To do.

  When the value of the brush deterioration diagnosis flag F is set to “1” in step S24, it is determined that the value of the brush deterioration diagnosis flag F is “1” in step S10, and the process proceeds to step S26. For this reason, since the process of step S12 is not performed, the automatic stop of the engine 36 is prohibited.

  In step S26, a process for notifying the driver that the brush 18 has deteriorated is performed. Specifically, for example, the driver may be notified by turning on an engine check lamp (failure warning lamp). Incidentally, the value of the brush deterioration diagnosis flag F is initialized (set to “0”) after repairs such as replacement of the brush 18 at a repair shop, for example.

  When a negative determination is made in steps S14, S16, S20, and S22, or when the processes in steps S24 and S26 are completed, the series of processes is temporarily terminated.

  FIG. 7 shows an example of the brush deterioration diagnosis process according to the present embodiment. Specifically, FIG. 7A shows the transition of the operation state of the ignition key 34, FIG. 7B shows the transition of whether or not the diagnosis execution condition is satisfied, and FIG. 7C shows the engine. The transition of whether or not the 36 restart condition is satisfied is shown, and FIG. 7D shows the transition of the temperature of the contact surface between the brush 18 and the commutator 24.

  As shown in the figure, at the time t1, the engine 36 is started for the first time by performing cranking by operating the ignition key 34 of the driver. After that, after the first start of the engine 36 is made (time t2) and after the timing (time t2) when the first specified time TA elapses, the second specification is started from the timing (time t3) when the restart processing of the plurality of times is completed. The diagnosis execution condition of the brush deterioration diagnosis process is satisfied at the timing (time t4) when the time TB elapses. After that, when the restart condition is satisfied at time t5, the brush deterioration diagnosis process is performed in a situation where cranking is performed.

  Thus, in the present embodiment, it is possible to diagnose with high accuracy whether or not the brush 18 is deteriorated by performing the brush deterioration diagnosis process based on the battery voltage fluctuation amount ΔV.

  According to the embodiment described in detail above, the following effects can be obtained.

  (1) The brush 18 in which the wear detection portion 18a has a lower ratio of copper to carbon than the normal portion 18b is employed. Thereby, when the brush 18 deteriorates, the difference in the battery voltage fluctuation amount ΔV can be appropriately generated.

  (2) When it is determined that the fluctuation amount ΔV of the battery voltage during cranking exceeds the specified value Vα, a brush deterioration diagnosis process for diagnosing that the brush 18 has deteriorated was performed. Thereby, it is possible to diagnose with high accuracy whether or not the brush 18 is deteriorated.

  (3) When it is determined that the logical product condition of the above conditions (A) to (C) is true, it is determined that the diagnosis execution condition is satisfied, and the brush deterioration diagnosis process is performed. Thereby, it is possible to diagnose with high accuracy whether or not the brush 18 is deteriorated.

  (4) When it is diagnosed that the brush 18 is deteriorated, a subsequent automatic stop of the engine 36 is prohibited, and a process of notifying the driver that the brush 18 is deteriorated is performed. As a result, it is possible to avoid a situation in which the starter 10 is continuously used in a state where the brush 18 is deteriorated. As a result, it is possible to avoid a situation in which the engine 36 cannot be restarted.

(Other embodiments)
Each of the above embodiments may be modified as follows.

  The calculation method of the battery voltage fluctuation amount ΔV is not limited to the one exemplified in the above embodiment. For example, subtracting the minimum value from the maximum value for each fluctuation cycle of the battery voltage, calculating a plurality of values obtained by subtracting the minimum value from the maximum value, and calculating the average value of the calculated plurality of subtraction values The fluctuation amount ΔV may be calculated using

  The parameter for diagnosing the presence / absence of the deterioration of the brush 18 is not limited to the battery voltage fluctuation amount ΔV, and for example, the starter current fluctuation amount detected by the current sensor 46 may be used.

  The diagnosis execution conditions for the brush deterioration diagnosis process are not limited to those exemplified in the above embodiment. For example, a sensor that detects the temperature of the engine 36 (for example, a water temperature sensor that detects the temperature of cooling water that cools the engine 36 or an oil temperature sensor that detects the oil temperature of the engine 36) is provided, and the above condition (A) is substituted. The engine 36 may be determined to have been warmed up based on the temperature detected by the sensor. Further, for example, in addition to the above conditions (A) to (C), a condition that the travel distance of the vehicle after the previous execution of the above-described diagnosis process is a specified distance or more may be included. This is based on the fact that the wear of the brush 18 does not proceed immediately.

  -The method of making the materials of the wear detection part 18a and the normal part 18b different is not limited to that exemplified in the above embodiment. For example, the ratio of copper to carbon in the wear detection unit 18a may be higher than that in the normal unit 18b. In this case, when the wear detector 18a is exposed to the commutator 24, the battery voltage fluctuation amount ΔV decreases. For this reason, when it is determined that the variation ΔV is equal to or less than the specified value Vα, it is diagnosed that the brush 18 is deteriorated.

  Further, for example, a material made of a predetermined material (carbon and copper) is used as the normal portion 18b, and a material other than this material (such as molybdenum, silver, or zinc phosphate) is used as the wear detecting portion 18a. By adding, you may make the material of the normal part 18b and the wear detection part 18a different. Further, for example, the material may be made different by changing the particle size of the copper powder as the raw material powder in each of the normal part 18b and the wear detection part 18a. Even in these cases, when each of the wear detection unit 18a and the normal unit 18b comes into contact with the commutator 24, the battery voltage fluctuation amount ΔV changes due to a change in the degree of heat generation on the contact surface. The presence or absence of 18 deterioration can be diagnosed.

  -The surface of the brush 18 that is spaced from the surface that contacts the commutator 24 toward the brush 18 is exposed to the commutator 24, so that the amount of variation in the starter current is different from that before the spaced surface is exposed. The brush 18 is not limited to a material whose material is different. For example, the brush 18 may be configured such that the shape of the layer separated from the contact surface S with the commutator 24 toward the brush 18 in the brush 18 is different from the shape of the other portions. Specifically, for example, as shown in FIG. 8A, for the brush 18 made of the same material, a single or central portion of the side surface of the brush 18 (the surface of the brush 18 that is perpendicular to the contact surface S) or A plurality of depressions (a single depression is illustrated in the figure) may be formed. Even in this case, when the portion where the depression is formed as shown in FIG. 8B is exposed to the commutator 24 due to the progress of the brush wear, the shape of the contact surface between the brush 18 and the commutator 24 changes. The variation amount ΔV of the battery voltage changes due to the change of the spark generation mode. In order to return the characteristics of the starter 10 to the normal characteristics as soon as possible after the portion where the depression is formed is exposed to the commutator 24, it is desirable not to make the depression shape excessively large. Further, instead of the hollow shape, a through hole may be formed on the side surface of the brush 18.

  Furthermore, for example, by adopting a configuration in which the pressing force of a part of the brushes 18 of the brushes 18 included in the starter 10 against the commutator 24 changes as the brush wear progresses, the starter current increases as the brush wear progresses. The brush 18 may be provided with a function of making the variation amount of the brushes different. Specifically, while the length of the part of the brushes 18 is shorter than the length of the other brushes 18, the pressing force of the part of the brushes 18 is the pressing force of the other brushes 18 until the brush deteriorates. A configuration that is substantially the same as that described above may be employed. This is based on the fact that it is considered that when the pressing force changes, the amount of change in the starter current changes due to the degree of heat generation at the contact surface, the change in the contact state between the brush 18 and the commutator 24, and the like. In this case, the surface of the brush 18 that is separated from the surface that contacts the commutator 24 toward the brush 18 is the surface that faces the commutator 24 in the part of the brush 18 that has become shorter due to brush wear. Say.

  The method for setting the specified value Vα is not limited to that exemplified in the above embodiment. For example, the specified value Vα may be variably set based on the temperature of the engine 36 (the temperature of cooling water for cooling the engine 36 or the oil temperature of the engine 36). Thereby, it is possible to set an appropriate specified value Vα that reflects the difference in temperature of the engine 36 when the engine 36 is in a warm-up state.

  -As a diagnostic method of the presence or absence of deterioration of the brush 18, it is not restricted to what was illustrated to the said embodiment. For example, when it is determined a plurality of times that the battery voltage fluctuation amount ΔV exceeds the specified value Vα, it may be diagnosed that the brush 18 is deteriorated. Thereby, a highly reliable diagnosis result can be obtained. Further, for example, the battery voltage fluctuation amount at the initial stage of use shortly after the starter 10 is shipped is stored in the storage means (non-volatile memory or the like) of the ECU 42, and the battery voltage fluctuation amount in the diagnostic processing executed thereafter is Further, it may be diagnosed whether the brush 18 is deteriorated based on the stored fluctuation amount. Specifically, if it is determined that the battery voltage fluctuation amount deviates from the stored fluctuation amount by a predetermined value or more, it may be diagnosed that the brush 18 is deteriorated.

  DESCRIPTION OF SYMBOLS 10 ... Starter, 18 ... Brush, 18a ... Wear detection part, 18b ... Normal part, 24 ... Commutator, 26 ... Spring, 28 ... Battery, 34 ... Ignition key, 42 ... ECU (one embodiment of starter abnormality diagnosis device) .

Claims (4)

A starter configured to have a brush pressed against the commutator and contacting the commutator; and a process of automatically stopping the engine; and after the process of automatically stopping, cranking by the starter is performed to perform the engine Applied to a vehicle comprising means for performing a process of restarting
The brush has a function of making the amount of fluctuation of the current flowing through the brush different from that before the exposure by exposing a surface of the brush that is spaced from the surface in contact with the commutator to the brush side. It is prepared
Detection means for detecting a current flowing through the brush or a parameter value correlated therewith;
Diagnostic means for performing a process of diagnosing the presence or absence of deterioration of the brush based on a fluctuation amount of a detection value of the detection means at the time of the cranking ;
The diagnosis means performs the diagnosis process when it is determined that the restart process has been performed a plurality of times after the engine has been started by the operation of an ignition key of a driver. Diagnostic device.   The brush is configured such that the material or shape of a layer of the brush that is spaced from the surface in contact with the commutator toward the brush is different from the material or shape of other portions. The starter abnormality diagnosis device according to claim 1. The diagnosis unit performs the diagnosis process based on a fluctuation amount of a detection value of the detection unit when a temperature of a contact surface between the brush and the commutator is assumed to be a reference temperature. The starter abnormality diagnosis device according to claim 1 or 2 . When the diagnosis means diagnoses that the brush is deteriorated, the diagnosis means further comprises a processing means for performing at least one of a process for notifying the driver of the fact and a process for prohibiting the automatic stop process. The starter abnormality diagnosis device according to any one of claims 1 to 3 .

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