JP2016125960A - Abnormality detection unit and abnormality detection method of vehicular motor temperature sensor - Google Patents

Abstract

PROBLEM TO BE SOLVED: To alleviate a load of processing while effectively discriminating deterioration of a motor temperature sensor.SOLUTION: A CPU5 decides whether a predetermined time or more has elapsed since a start switch 10 of a vehicle is turned off. If the predetermined time or more has elapsed, data of a detected motor temperature Tm detected by a motor temperature sensor 7 and data of a detected coolant temperature Tc detected by a water temperature sensor 8 are recorded in a recording memory 6. The CPU 5 reads the data items of the detected motor temperature Tm and detected coolant temperature Tc stored in the recording memory 6, calculates the relationship (current characteristic) between the temperatures as a linear function, compares the relationship with a normal characteristic stored in advance, and discriminates a deteriorated state of the motor temperature sensor 7. This processing is performed when the start switch 10 is turned on.SELECTED DRAWING: Figure 1

Description

  The present invention relates to an abnormality detection device and an abnormality detection method for a vehicle motor temperature sensor that is mounted on, for example, a hybrid vehicle and detects the temperature of a motor.

  For example, in a hybrid vehicle having both an engine and a motor as a drive source, and a vehicle equipped with a motor as a drive source, a motor temperature sensor including, for example, a thermistor for detecting the motor temperature is provided to monitor the motor temperature. Things have been done. This type of motor temperature sensor is likely to deteriorate with long-term use, and detection characteristics may be deteriorated (abnormal). Therefore, conventionally, it has been considered to provide an abnormality detection device that detects an abnormality that has occurred in the thermistor that measures the motor temperature (see, for example, Patent Document 1).

  The abnormality detection device of Patent Document 1 applies a voltage for measuring a motor coil, detects the behavior of the current flowing in the motor coil and the electrical angle of the motor, and determines the resistance value of the coil from these detected values. The state of the thermistor is determined based on the calculation, estimating the coil temperature from the coil resistance value, and comparing the estimated coil temperature with the coil temperature measured by the thermistor. The above process is executed by the CPU every predetermined time so that the thermistor state is always detected.

Japanese Patent Laid-Open No. 10-62266

  However, in the above conventional motor temperature sensor abnormality detection device, the processing for determining the state is always repeated, so that the processing load on the CPU is large. Moreover, in order to estimate the motor temperature, a relatively complicated process such as the detection of the current behavior and the electrical angle with respect to the application of the measurement voltage, the calculation of the coil resistance, and the estimation of the coil temperature is performed. The amount of calculation required for the estimation (state determination) process has also increased.

  The present invention has been made in view of the above circumstances, and an object thereof is to detect abnormality of a motor temperature sensor for a vehicle that can reduce the load of processing for the deterioration of the motor temperature sensor while effectively determining the deterioration of the motor temperature sensor. It is in providing an apparatus and an abnormality detection method.

  In order to achieve the above object, a vehicle motor temperature sensor abnormality detection device (3) according to the present invention is provided in a vehicle and detects the temperature of a motor (1) serving as a driving source for the vehicle. (7) for determining deterioration, a determination means (5) for determining whether or not a predetermined time has elapsed since the start switch (10) of the vehicle was turned off last time, and the determination means ( 5) A cooler that cools the detected motor temperature detected by the motor temperature sensor (7) and the motor (1) and its drive circuit (2) when it is determined that a predetermined time or more has elapsed. Data of the detected coolant temperature detected by the cooling temperature sensor (8) for detecting the coolant temperature in (4) is recorded in the memory (6) and recorded in the memory (6). Stored detection motor temperature and Current characteristic calculation means (5) for reading a plurality of data of the outgoing coolant temperature and calculating the relationship between the detected motor temperature and the detected coolant temperature as a linear function, and the normal motor temperature and cooling stored in advance A deterioration state of the motor temperature sensor (7) is determined based on a comparison between the normal characteristic obtained as a linear function with respect to the liquid temperature and the current characteristic calculated by the current characteristic calculation means (5). Degradation determination means (5), and the processing by the determination means (5), recording means (5), current characteristic calculation means (5), and degradation determination means (5) is performed when the start switch (10) is turned on. It is characterized in that it is executed (the invention of claim 1).

  According to a fifth aspect of the present invention, there is provided a vehicle motor temperature sensor abnormality detection method for deterioration of a motor temperature sensor (7) that is provided in a vehicle and detects the temperature of a motor (1) that is a driving source for the vehicle. A determination method for determining whether or not a predetermined time has elapsed since the vehicle start switch (10) was turned off last time, and determining that a predetermined time or more has elapsed in the determination step. Temperature sensor for detecting the detected motor temperature detected by the motor temperature sensor (7) and the coolant temperature of the cooler (4) for cooling the motor (1) and its drive circuit (2). A recording step of accumulating and recording data on the detected coolant temperature detected in (8) in the memory (6), and a plurality of data on the detected motor temperature and detected coolant temperature stored in the memory (6). reading A current characteristic calculation step for calculating the relationship between the detected motor temperature and the detected coolant temperature as a linear function, and a normal characteristic obtained by calculating the relationship between the normal motor temperature and the coolant temperature stored in advance as a linear function, A deterioration determination step of determining a deterioration state of the motor temperature sensor (7) based on comparison with the current state characteristics calculated in the current state characteristic calculation step, and each step includes the start switch (10). ) Is executed when it is turned on (the invention of claim 5).

  According to the above configuration, when the vehicle start switch (10) is turned on, a predetermined time or more has passed since the vehicle start switch (10) was previously turned off by the determination means (5) (in the determination step). It is determined whether it has elapsed. When it is determined by the determining means (5) that the predetermined time or more has elapsed (in the determining process), the detected motor detected by the motor temperature sensor (7) by the recording means (5) (in the recording process) Data on the temperature and the detected coolant temperature detected by the cooling temperature sensor (8) is accumulated and recorded in the memory (6). At this time, the “predetermined time” refers to the time required for the motor temperature and the coolant temperature to decrease according to the outside air temperature after the start switch (10) is turned off and finally balance. Just do it. Specifically, for example, it can be any one of 6 hours to 12 hours.

  Here, the temperature of the motor (1) and the temperature of the coolant stored in the memory (6) vary depending on the outside air temperature or the like, but when the temperature sensor is normal, the motor temperature sensor (7) A predetermined linear function relationship should be obtained between the detected motor temperature detected by the above and the detected coolant temperature detected by the cooling temperature sensor (8). Therefore, the normal characteristic obtained by calculating the relationship between the normal motor temperature and the coolant temperature as a linear function is stored in advance, and the relationship between the current motor temperature and the coolant temperature is obtained as a linear function (current characteristic). ), The deterioration state of the motor temperature sensor can be determined.

  In the present invention, a plurality of data stored in the memory (6) is read out by the current characteristic calculation means (5) (in the current characteristic calculation step), and the relationship between the detected motor temperature and the detected coolant temperature (current condition) Characteristic) is calculated as a linear function. Then, the deterioration determination means (5) (in the deterioration determination step) determines the deterioration state of the motor temperature sensor (7) based on comparing the normal characteristic stored in advance with the calculated current characteristic. The Thereby, the deterioration state of the motor temperature sensor (7) can be determined with sufficient certainty by a relatively simple process.

  At this time, the deterioration of the motor temperature sensor (7) progresses gradually, does not occur immediately after the start of use, and does not significantly deteriorate in a short time. In the present invention, each process (deterioration determination process, etc.) such as deterioration determination by the deterioration determination means (5) is executed when the start switch (10) is turned on. Since the deterioration determination is performed at a frequency of, for example, once or several times a day when the start switch (10) is turned on, the processing load can be greatly reduced as compared with the case where the determination process is always performed. it can. Further, even if the frequency of performing the deterioration determination is low, there is no practical problem.

The 1st Embodiment of this invention is a block diagram which shows the electrical structure of the principal part roughly The flowchart which shows the general | schematic procedure of the whole abnormality detection process which CPU performs. The flowchart which shows the procedure of the deterioration determination process which CPU performs. The figure which shows the mode of the fluctuation | variation of the detected value of motor temperature and coolant temperature Diagram showing examples of normal and current characteristic lines The flowchart which shows the 2nd Embodiment of this invention and shows the procedure of the deterioration determination process which CPU performs. The flowchart which shows the 3rd Embodiment of this invention and shows the procedure of the deterioration determination process which CPU performs. The figure which shows the relation between the electric current which flows to the motor and the high load current frequency counter The flowchart which shows the 4th Embodiment of this invention and shows the procedure of the deterioration determination process which CPU performs. The figure for explaining the trouble when the difference between the maximum value and the minimum value of the detected coolant temperature is small

  Hereinafter, some embodiments embodying the present invention will be described with reference to the drawings. In the following embodiments, the present invention is applied to a hybrid vehicle (or an electric vehicle).

(1) First Embodiment A first embodiment of the present invention will be described with reference to FIGS. FIG. 1 schematically shows an electrical configuration of a traveling motor 1 that is mounted on a hybrid vehicle and serves as a traveling drive source, and its peripheral portion. Here, the motor 1 is driven by an inverter device 2 as a drive circuit, and the inverter device 2 is controlled by a motor control device (ECU) 3 for a motor generator (MG).

  Although not shown in detail, the inverter device 2 includes a boost converter that boosts the voltage of the HV battery for a power source, and a three-phase inverter that converts the boosted DC voltage into a three-phase AC to drive the motor 1. A circuit is provided. And the cooler 4 which cools the components etc. which comprise the said motor 1 and the inverter apparatus 2 is provided. In the present embodiment, the cooler 4 circulates and supplies a cooling liquid (for example, cooling water) to a cooling pipe disposed so as to be in thermal contact with each component of the motor 1 and the inverter device 2. It is configured.

  The motor control device 3 includes a CPU 5 that performs calculation processing and the like, and a recording memory 6 that stores calculation results and the like. The motor control device 3 is configured to output a control signal to the inverter device 2 to drive and control the motor 1. The motor 1 is provided with a motor temperature sensor 7 that detects the temperature of the motor 1. The motor temperature sensor 7 is composed of, for example, a thermistor, and a detection signal (detected motor temperature Tm) is input to the motor control device 3 (CPU 5).

  Further, the cooler 4 is provided with a water temperature sensor 8 as a cooling temperature sensor which is also a thermistor for detecting the temperature of the coolant. A detection signal (detected coolant temperature Tc) of the water temperature sensor 8 is also input to the motor control device 3 (CPU 5). Further, a host ECU 9 such as a vehicle control ECU is connected to the motor control device 3 (CPU 5). A vehicle start switch (ignition switch) 10 is connected to the host ECU 9, and an ON / OFF signal of the start switch 10 is input to the motor control device 3 (CPU 5) via the host ECU 9. It has become.

  Now, the CPU 5 of the motor control device 3 determines the deterioration of the motor temperature sensor 7 by its software configuration (execution of the temperature sensor abnormality determination program), and the abnormality detection device according to the present embodiment. Function (each step of the abnormality detection method) is realized. That is, the CPU 5 functions as a determination unit, a recording unit, a current characteristic calculation unit, and a deterioration determination unit. At this time, the recording memory 6 also stores normal characteristic data (normal characteristic line L1), which will be described later. The temperature sensor abnormality determination program may be stored in advance in a ROM or the like, or may be provided via a recording medium such as a network or an optical disk.

  Specifically, as will be described later in the description of the operation (flowchart description), the CPU 5 of the motor control device 3 executes the following processes (each process) when the start switch 10 of the vehicle is turned on. That is, first, the CPU 5 determines whether or not a predetermined time (for example, 6 hours) or more has elapsed since the start switch 10 of the vehicle was turned off last time (determination step). If it is determined that the predetermined time has elapsed, the CPU 5 records data (recording) of the detected motor temperature Tm detected by the motor temperature sensor 7 and the detected coolant temperature Tc detected by the water temperature sensor 8. Are stored and recorded in the recording memory 6 (recording step). Of course, the detected motor temperature Tm and the detected coolant temperature Tc are stored in association with each other so as to form a one-to-one pair.

  Note that the data of the detected motor temperature Tm and the detected coolant temperature Tc are recorded in the recording memory 6 up to, for example, 10 pieces (10 sets), and when the number is exceeded, the oldest data is deleted from the recording memory 6 in order. The latest 10 pieces of data are always stored. In addition, when the predetermined time (6 hours) has not elapsed since the start switch 10 was turned off last time, the data of the detected motor temperature Tm and the detected coolant temperature Tc are recorded in the recording memory 6. Absent.

  Then, the CPU 5 reads a plurality of data of the detected motor temperature Tm and the detected coolant temperature Tc stored in the recording memory 6, and the relationship between the detected motor temperature Tm and the detected coolant temperature Tc is a linear function (current state). Characteristic straight line L2) is calculated (current characteristic calculating step). Subsequently, the CPU 5 determines the deterioration state of the motor temperature sensor 7 based on the comparison between the normal characteristic (normal characteristic straight line L1) stored in advance and the current characteristic (current characteristic straight line L2) (deterioration determination). Process). In this case, the normal characteristic is obtained on a trial (or theoretical) basis as a linear function of the relationship between the normal motor temperature and the coolant temperature on the manufacturer side, and is stored in the recording memory 6 in advance. Each process (each process) described above is executed when a signal indicating that the start switch 10 is turned on is given from the host ECU 9.

  Next, the operation of the above configuration (each step of the abnormality detection method of the motor temperature sensor 7 of the present embodiment) will be described with reference to FIGS. The flowchart of FIG. 2 shows an overall rough processing procedure regarding abnormality detection of the motor temperature sensor 7 that is executed by the CPU 5 of the motor control device 3 when the start switch 10 is turned on. Further, the flowchart of FIG. 3 shows a detailed procedure of the deterioration determination process in step S2 in the process of FIG.

  First, in FIG. 2, when the activation switch 10 is turned on and the abnormality detection process of the motor temperature sensor 7 is started, it is determined in step S1 whether or not the initial flag is “1 (initial)”. The initial flag is configured to be “1: initial” when the start (IG) switch 10 is turned on. When the initial flag is “1 (initial)” (Yes in step S1), the process proceeds to step S2 and the deterioration determination process is executed. Details of this deterioration determination process will be described later. When the deterioration determination process (step S2) ends, the initial flag is set to “0” in step S3, and then the process proceeds to step S4.

  In step S4, the disconnection determination process of the motor temperature sensor 7 is executed. Furthermore, in step S5, a short circuit determination process for the motor temperature sensor 7 is executed. A known technique can be employed for the disconnection determination process (S4) and the short circuit determination process (S5). For example, since it is known in Japanese Patent Application Laid-Open No. 2013-242225 related to the applicant's application, the description thereof is omitted here. When the disconnection determination process and the short circuit determination process are completed, the processes from step S1 are repeated. In this case, since the initial flag is “0” from the second time through step S3 (No in step S1), the deterioration determination process in step S is not executed, and the disconnection determination process and The short circuit determination process is repeatedly executed. That is, the deterioration determination process is executed only once when the start switch 10 is turned on.

  Now, the details of the deterioration determination process will be described with reference to FIG. When the deterioration determination process is started, first, in step S11, a plurality of data (recording array) of the detected motor temperature Tm by the motor temperature sensor 7 is acquired from the recording memory 6. At the same time, in step S12, a plurality of data (recording arrangement) of the coolant temperature Tc detected by the water temperature sensor 8 is acquired from the recording memory 6. In step S13, normal characteristic data (inclination a1 and intercept b1 of the normal characteristic line L1) stored in advance are acquired from the recording memory 6.

  Here, the normal characteristic of step S13 is an equilibrium state (the temperature of the motor 1 and the coolant is lower) when the motor temperature sensor 7 (and the water temperature sensor 8) is operating normally (deterioration has not progressed). The ideal (theoretical) relationship between the detected motor temperature Tm and the detected coolant temperature Tc in a state of being balanced with the outside air temperature is obtained as a linear function. As shown in FIG. 5, the normal characteristic line L1 is represented by a linear function y = a1x + b1 where the detected motor temperature Tm is y and the detected coolant temperature Tc is x.

  Returning to FIG. 3, in the next step S <b> 14, a variable N representing the number of data (recording array data) of the detected motor temperature Tm and the detected coolant temperature Tc is acquired from the recording memory 6. In step S <b> 15, data of the previous off time (time) of the start switch 10 is acquired from the host CPU 9. In step S16, it is determined whether or not a predetermined time (for example, 6 hours as a threshold) has elapsed since the vehicle start switch 10 was turned off last time. The predetermined time is a time required for the temperature of the motor 1 and the temperature of the coolant to decrease according to the outside air temperature after the start switch 10 is turned off and finally balance. For example, it can be any of 6 hours to 12 hours.

  If the predetermined time or more has not elapsed since the previous start switch 10 was turned off (No in step S16), the process directly proceeds to step S23. On the other hand, when a predetermined time or more has elapsed since the time when the start-up switch 10 was previously turned off (Yes in step S16), the current detected motor temperature Tm of the motor temperature sensor 7 is acquired in step S17. And stored in the recording array. At the same time, in step S18, the current detected coolant temperature Tc of the water temperature sensor 8 is acquired and stored in the recording array.

  In step S <b> 19, a new recording arrangement of the detected motor temperature Tm of the motor temperature sensor 7 is stored in the recording memory 6. At the same time, a new recording arrangement of the detected coolant temperature Tc of the water temperature sensor 8 is stored in the recording memory 6 in step S20. In step S21, a variable N representing the number of data (recording array data) of the detected motor temperature Tm and the detected coolant temperature Tc is incremented by 1, and a new variable N is recorded in the recording memory 6 in step S22. Then, the process proceeds to step S23.

  Here, FIG. 4 shows detected temperatures of the detected motor temperature Tm and the detected coolant temperature Tc with respect to ON / OFF of the start switch 10 when the motor temperature sensor 7 (and the water temperature sensor 8) is operating normally. An example of the behavior is shown. In the driving state of the motor 1, the components constituting the motor 1 and the inverter device 2 serve as heat generation sources, and the temperature of the motor 1 and the temperature of the coolant in the cooler 4 are high. On the other hand, in the state where the start switch 10 is turned off, all the heat sources are stopped, so that the temperature of the motor 1 and the coolant (the detected motor temperature Tm and the detected coolant temperature Tc) gradually decreases due to natural cooling. Go.

  And after predetermined time (for example, 6 hours) passes, it comes to equilibrate with external temperature until the next starting switch 10 is turned on. If the motor temperature sensor 7 is normal, a constant linear function that varies according to the outside air temperature or the like is obtained between the detected motor temperature Tm and the detected coolant temperature Tc after a predetermined time has elapsed. It is a spear. The outside air temperature fluctuates depending on the season, time zone, parking state (position) of the vehicle, and the like. In the present invention, the deterioration of the motor temperature sensor 7 is determined using the linear function relationship between the detected motor temperature Tm and the detected coolant temperature Tc after the lapse of the predetermined time.

  Returning to FIG. 3, in step S <b> 23, it is determined whether or not the variable N representing the number of data (recording arrays) is greater than or equal to a predetermined value (for example, 2). If it is less than the predetermined value (No in step S23), the deterioration determination process is terminated. If the variable N is equal to or greater than the predetermined value (Yes in step S23), in step S24, the detected motor is detected from the recording array of the detected motor temperature Tm and the detected coolant temperature Tc using the least square method. A straight line L2 (inclination a2 and intercept b2) of the current characteristics calculated as a linear function of the relationship between the temperature Tm and the detected coolant temperature Tc is obtained. As shown in FIG. 5, the current characteristic line L2 is also represented by a linear function y = a2x + b2 where the detected motor temperature Tm is y and the detected coolant temperature Tc is x.

  In the next step S25, the distances d1 and d2 between the straight lines are obtained from the slope a1 and intercept b1 of the normal characteristic line L1 and the slope a2 and intercept b2 of the current characteristic line L2. As shown in FIG. 5, the distance d1 between the straight lines is a difference in the value of y between the normal characteristic line L1 and the current characteristic line L2 when the detected motor temperature Tm (x) is the temperature T1 (low temperature side). The distance d2 between the straight lines is a difference in the value of y between the normal characteristic line L1 and the current characteristic line L2 when the detected motor temperature Tm (x) is the temperature T2 (high temperature side). In this case, the temperatures T1 and T2 are selected from two temperatures on the low temperature side and the high temperature side in the temperature range measured by the motor temperature sensor 7, for example, the temperature T1 is set to 80 ° C. and the temperature T2 is set to 120 ° C. The

  In step S <b> 26, it is determined whether the values of the distances d <b> 1 and d <b> 2 between the straight lines are larger than a deterioration determination threshold value (for example, 10 ° C.). If either one or both of the distances d1 and d2 between the straight lines is larger than the threshold value (Yes in step S26), it is determined in step S27 that the motor temperature sensor 7 has deteriorated, and the deterioration determination flag is set to “ The deterioration determination process is terminated. If both of the distances d1 and d2 between the straight lines are equal to or less than the threshold value (No in step S26), the deterioration determination process is ended without being determined as deterioration.

  Through the above process, in the deterioration determination step, the normal characteristic (normal characteristic straight line L1) stored in advance is compared with the calculated current characteristic (current characteristic straight line L2). A degradation state is determined. Thereby, the deterioration state of the motor temperature sensor 7 can be determined with sufficient reliability by a relatively simple process. At this time, the deterioration of the motor temperature sensor 7 is gradually progressed and occurs for the first time after several months to several years at the earliest after the start of use of the vehicle, and the deterioration greatly proceeds in a short time. I don't have to. In the present embodiment, each process such as a deterioration determination (a process such as a deterioration determination process) is executed when the start switch 10 of the vehicle is turned on.

  As described above, since the deterioration determination is performed at a frequency of about once or several times a day when the start switch 10 is turned on, the processing load on the CPU 5 is greatly increased as compared with the case where the determination process is always performed. Can be reduced. Further, even if the frequency of performing the deterioration determination is low, there is no practical problem. Therefore, according to the present embodiment, while it is possible to effectively determine the deterioration of the motor temperature sensor 7, it is possible to reduce the processing load for that purpose.

(2) Second Embodiment Next, a second embodiment of the present invention will be described with reference to FIG. In each of the embodiments described below, the present invention is applied to a hybrid vehicle, and the hardware configuration and the like are the same as those in the first embodiment. Therefore, the same parts as those in the first embodiment are denoted by the same reference numerals, and new illustrations and detailed descriptions are omitted. Hereinafter, differences from the first embodiment will be described.

  The second embodiment is different from the first embodiment in the following points. That is, in the deterioration determination process of the motor temperature sensor 7 executed by the CPU 5, when the deterioration of the motor temperature sensor 7 is determined (step S27), the detected value (detection) of the motor temperature sensor 7 is detected in step S31. A process (correction coefficient calculation step) for calculating correction coefficients a3 and b3 for correcting the motor temperature Tm) is executed. Therefore, in the second embodiment, the CPU 5 also functions as a correction coefficient calculation unit.

At this time, a calculation formula for correcting the detected value (detected motor temperature Tm) of the deteriorated motor temperature sensor 7 to the correct motor temperature Tth is obtained by using correction coefficients a3 and b3.
Tth = Tm × a3 + b3
It is represented by The correction coefficient a3 can be obtained by a3 = a1 / a2. The correction coefficient b3 can be obtained by b3 = b2 × (a1 / a2) + b1.

  According to the second embodiment, in addition to the same operations and effects as those of the first embodiment, even when the deterioration of the motor temperature sensor 7 is determined, the correction coefficient calculation step (step S31). By using the calculated correction coefficients a3 and b3, it is possible to obtain a sufficiently accurate motor temperature detection value Tth by correcting the detection value (detected motor temperature Tm) of the motor temperature sensor 7. As a result, the lifetime of the motor temperature sensor 7 can be extended. In addition, as a process when it is determined that the motor temperature sensor 7 is deteriorated, it is possible to notify the user to that effect and prompt repair or replacement.

(3) Third Embodiment FIGS. 7 and 8 show a third embodiment of the present invention. The third embodiment is different from the first embodiment in that the number of times that a large current of a predetermined value E (for example, 100 A) or more flows to the control device 3 (recording memory 6) through the motor 1 is counted. A high load current number counter (accumulation) is provided, and deterioration determination (degradation determination step) by the CPU 5 (degradation determination means) is performed. After that, it is in a point to be executed.

  FIG. 8 schematically shows the relationship between the value of the current flowing through the motor 1 and the high load current number counter over time. Here, when the state where a large current of a predetermined value E (100 A) or more flows through the motor 1 continues for ΔT (for example, several tens of seconds) or more, the high load current number counter is incremented by one. That is, even if a large current flows through the motor 1 for a short time less than ΔT, it does not count. Experimentally (empirically), after the start of use, the value of the high load current number counter gradually increases and becomes a predetermined number F (3,000 times) or more in several months or years.

  As shown in FIG. 7, in the present embodiment, when the deterioration determination process is started, first, in step S41, it is determined whether the value of the high load current number counter is equal to or greater than a threshold value (eg, 3000). . Then, when the value of the high load current number counter is less than the predetermined value (No in step S41), the process is ended as it is. Only after the value of the high load current number counter becomes equal to or greater than a predetermined value, the processing (steps of deterioration determination) from step S11 is executed as in the first embodiment.

  Here, as one factor for the deterioration of the motor temperature sensor 7 to proceed, it is conceivable that a large current of a predetermined value or more flows to the motor 1 and the temperature becomes abnormally high. In other words, the motor temperature sensor 7 does not deteriorate as long as the number of times a large current of a predetermined value or more flows through the motor 1 is still small. Therefore, when the integrated value of the number of times that a large current greater than or equal to a predetermined value flows to the motor 1 is less than the predetermined number, there is very little possibility that the deterioration has progressed, and the deterioration determination need not be performed.

  According to the third embodiment, in addition to the same operation and effect as the first embodiment, when the motor temperature sensor 7 is likely to deteriorate, the deterioration determination is performed for the first time. The processing load can be further reduced.

(4) Fourth Embodiment and Other Embodiments FIG. 9 and FIG. 10 show a fourth embodiment of the present invention. The fourth embodiment differs from the first embodiment in that the deterioration determination process (steps S24 to S27) of the deterioration determination process of the motor temperature sensor 7 executed by the CPU 5 is performed in the recording memory 6. The difference is that the difference between the maximum value and the minimum value of the detected coolant temperature Tc recorded in the above is a predetermined threshold value (for example, 15 ° C.) or more. The threshold value can be set to any one of 10 to 20 ° C., for example.

  Here, as shown in FIG. 10, when the number of data recorded in the recording memory 6 is still small, the difference between the maximum value and the minimum value of the detected coolant temperature Tc is still relatively small (less than a predetermined value). There is a case). The linear function (current characteristic line L21) of the current characteristic obtained from such data by calculation (least square method) has a relatively large inclination error with respect to the straight line L22 that should be originally obtained, and is thus sufficiently correct. There is a possibility that the judgment cannot be made. On the other hand, when the difference between the maximum value and the minimum value of the detected coolant temperature Tc is relatively large (greater than or equal to a predetermined value), the current characteristic line L23 obtained by calculation from a plurality of data is originally obtained. The error from the power line L24 is small.

  As shown in FIG. 9, in the present embodiment, in the deterioration determination process, the CPU 5 determines in step S23 that the variable N representing the number of data (recording arrays) is greater than or equal to a predetermined value (step S23). Is Yes), whether or not the difference between the maximum value and the minimum value of the data (recording array) of the detected coolant temperature Tc detected by the water temperature sensor 8 in the next step S51 is greater than or equal to a predetermined value. To be judged. If the difference between the maximum value and the minimum value is less than the predetermined value (No in step S51), the process is ended as it is. When the difference between the maximum value and the minimum value is equal to or greater than the predetermined value (Yes in step S51), the processing from step S24 (degradation determination step) is executed.

  According to the fourth embodiment, in addition to the same operation and effect as those of the first embodiment, the difference between the maximum value and the minimum value of the detected coolant temperature Tc is predetermined. Since the deterioration determination is executed on condition that the value is equal to or greater than the value, the error can be reduced and determination with higher accuracy can be performed.

  In each of the above embodiments, the present invention is applied to a hybrid vehicle. However, the present invention can be applied to all vehicles including a motor such as an electric vehicle and a fuel cell vehicle as a drive source. Various changes can be made to the configuration of the drive circuit and the cooler. Furthermore, numerical values such as threshold values (predetermined values) in the above-described embodiment are merely examples. In addition, the present invention may be implemented by combining the above-described second to fourth embodiments. The present invention can be implemented with appropriate modifications within a range not departing from the gist.

  In the drawings, 1 is a motor, 2 is an inverter device (drive circuit), 3 is a control device (abnormality detection device), 4 is a cooler, 5 is a CPU (determination means, recording means, current characteristic calculation means, deterioration determination means, Correction coefficient calculation means), 6 is a recording memory (memory), 7 is a motor temperature sensor, 8 is a temperature sensor for cooling, 9 is a host ECU, and 10 is a start switch.

Claims (8)

An abnormality detection device (3) for a vehicle motor temperature sensor for determining deterioration of a motor temperature sensor (7) that is provided in a vehicle and detects a temperature of a motor (1) that is a driving drive source of the vehicle,
A judging means (5) for judging whether or not a predetermined time or more has passed since the start switch (10) of the vehicle was turned off last time;
When it is determined by the determination means (5) that a predetermined time or more has elapsed, the detected motor temperature detected by the motor temperature sensor (7), the motor (1) and its drive circuit (2) Recording means (5) for accumulating and recording in the memory (6) data of the detected coolant temperature detected by the cooling temperature sensor (8) for detecting the coolant temperature of the cooler (4) to be cooled;
Current characteristic calculation means (5) for reading a plurality of data of the detected motor temperature and the detected coolant temperature stored in the memory (6) and calculating a relationship between the detected motor temperature and the detected coolant temperature as a linear function. )When,
Based on the comparison between the normal characteristic obtained as a linear function of the relationship between the normal motor temperature and the coolant temperature stored in advance as a linear function, and the current characteristic calculated by the current characteristic calculation means (5) A deterioration determining means (5) for determining a deterioration state of the temperature sensor (7),
The processing by the determination means (5), recording means (5), current characteristic calculation means (5), and deterioration determination means (5) is executed when the start switch (10) is turned on. Abnormality detection device for motor temperature sensor   Correction coefficient calculation means (5) for calculating a correction coefficient for correcting the detected value of the motor temperature sensor (7) when the deterioration determination means (5) determines the deterioration of the motor temperature sensor (7). The abnormality detection device for a vehicle motor temperature sensor according to claim 1.   The deterioration determination by the deterioration determination means (5) is performed after an integrated value of the number of times that a large current greater than or equal to a predetermined value has flowed to the motor (1) has reached a predetermined number or more. Item 3. A vehicle motor temperature sensor abnormality detection device according to Item 1 or 2.   The deterioration determination by the deterioration determination means (5) is performed on condition that the difference between the maximum value and the minimum value of the detected coolant temperature recorded in the memory (6) is a predetermined value or more. The abnormality detection apparatus for a vehicle motor temperature sensor according to any one of claims 1 to 3. An abnormality detection method for a vehicle motor temperature sensor for determining deterioration of a motor temperature sensor (7) that is provided in a vehicle and detects the temperature of a motor (1) that serves as a travel drive source of the vehicle,
A determination step of determining whether or not a predetermined time has elapsed since the vehicle start switch (10) was turned off last time;
When it is determined in the determination step that a predetermined time or more has elapsed, a detected motor temperature detected by the motor temperature sensor (7), and a cooler that cools the motor (1) and its drive circuit (2) ( A recording step of accumulating and recording data of the detected coolant temperature detected by the cooling temperature sensor (8) for detecting the coolant temperature in 4) in the memory (6);
A current characteristic calculation step of reading a plurality of data of the detected motor temperature and the detected coolant temperature stored in the memory (6) and calculating a relationship between the detected motor temperature and the detected coolant temperature as a linear function;
Based on a comparison between the normal characteristic obtained as a linear function of the relationship between the normal motor temperature and the coolant temperature stored in advance as a linear function and the current characteristic calculated in the current characteristic calculation step, the motor temperature sensor ( 7) a deterioration determination step for determining a deterioration state,
Each of the steps is executed when the start switch (10) is turned on, and the vehicle motor temperature sensor abnormality detection method is characterized.   Executing a correction coefficient calculation step of calculating a correction coefficient for correcting the detected value of the motor temperature sensor (7) when the deterioration of the motor temperature sensor (7) is determined in the deterioration determination step; 6. A method for detecting an abnormality of a vehicle motor temperature sensor according to claim 5.   The deterioration determination in the deterioration determination step is performed after an integrated value of the number of times that a large current greater than or equal to a predetermined value has flowed through the motor (1) has reached a predetermined number or more. 7. An abnormality detection method for a vehicle motor temperature sensor according to claim 6.   The deterioration determination in the deterioration determination step is performed on condition that a difference between a maximum value and a minimum value of the detected coolant temperature recorded in the memory (6) is a predetermined value or more. Item 8. The abnormality detection method for a vehicle motor temperature sensor according to any one of Items 5 to 7.

Images