JP2012205448A - Vehicle diagnosis system - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a vehicle diagnosis system which can accurately detect a flow rate and can diagnose an operation state of a cooling pump without adding a new flowmeter.SOLUTION: The vehicle diagnosis system includes: a flow passage 116 which circulates a liquid medium for cooling an inverter 14 of a vehicle; an element temperature sensor 112 which detects temperatures of power control elements Q3 to Q8 in the inverter 14; a pump 104 which is set up in the flow passage to circulate the liquid medium; and a control device 30 which makes the power control elements Q3 to Q8 in the inverter 14 temporarily generate heat to diagnose the operation state of the pump 104 under a state meeting a condition in which other drive command is not given to the inverter 14, and then reduces heat generation of the power control elements Q3 to Q8, to diagnose the operation state of the pump 104 according to a decrease degree in the detection temperature of the element temperature sensor 112.

Description

  The present invention relates to a vehicle diagnostic system, and more particularly to a vehicle diagnostic system for diagnosing a pump operation state for cooling an in-vehicle inverter.

  It has been a long time since the issue of global warming began to be pointed out all over the world. Recently, a plug-in hybrid vehicle that can run like an electric vehicle or an electric vehicle that does not generate exhaust from an engine has been attracting attention as one of countermeasures against this problem.

  Japanese Patent Laying-Open No. 2005-224042 discloses a cooling device that estimates a target flow rate from a cooling water temperature for cooling an inverter mounted on an electric vehicle and controls a water pump.

JP 2005-224042 A

  In JP-A-2005-224042, the flow rate of cooling water is indirectly estimated. However, for example, when the estimated flow rate is used for determining the abnormality of the flow rate of the water pump, it is desirable that the flow rate detection be performed with high accuracy.

  An object of the present invention is to provide a vehicle diagnostic system capable of accurately detecting a flow rate and diagnosing an operating state of a cooling pump without adding a new flow meter.

  In summary, the present invention is a vehicle diagnostic system provided on a flow path for circulating a liquid medium for cooling a vehicle inverter, an element temperature sensor for detecting the temperature of a power control element in the inverter, and the flow path. The power control element in the inverter was temporarily heated in order to diagnose the operation status of the pump under the condition that the pump for circulating the liquid medium and the condition that no other drive command for the inverter was issued And a diagnostic device that reduces heat generation of the rear power control element and diagnoses the operation state of the pump according to the degree of decrease in the temperature detected by the element temperature sensor.

  Preferably, the diagnosis execution condition includes a condition that it is within a predetermined period after the system start signal is given to the vehicle or within a predetermined period after the system stop signal is given to the vehicle.

  More preferably, the diagnosis execution condition further includes a condition that the shift range is set to the parking range and the accelerator pedal is not operated.

  More preferably, the diagnostic device causes the power control element to generate heat by temporarily outputting a command torque to the inverter even when the accelerator pedal is not operated.

  More preferably, the vehicle diagnosis system further includes a liquid temperature sensor that detects the temperature of the liquid medium. The diagnostic device determines the magnitude of the command torque based on the temperature detected by the liquid temperature sensor.

  According to the present invention, it is possible to accurately detect the flow rate without adding a new flow meter, and thus it is possible to accurately diagnose the operating state of the cooling pump.

1 is a circuit diagram showing a configuration of a vehicle 100 equipped with a vehicle cooling system. It is a figure for demonstrating the principle of the estimation of the flow volume in this Embodiment. It is a wave form diagram for demonstrating the diagnosis time of the water pump of a cooling system. It is a flowchart for demonstrating control of the water pump diagnostic time shown in FIG. It is a flowchart for demonstrating the flow volume determination process used at the time of the diagnosis of the water pump of step S2 of FIG. It is the figure which showed an example of the water temperature-command torque map referred in step S23 of FIG. It is a figure for demonstrating the measurement of the fall rate of temperature. It is a figure which shows an example of a descent | fall rate flow map.

  Hereinafter, embodiments of the present invention will be described in detail with reference to the drawings. In the drawings, the same or corresponding parts are denoted by the same reference numerals and description thereof will not be repeated.

  FIG. 1 is a circuit diagram showing a configuration of a vehicle 100 equipped with a vehicle cooling system. The vehicle 100 is an example of an electric vehicle. However, as long as the vehicle is equipped with a cooling system, the present invention can be applied to a hybrid vehicle and a fuel cell vehicle using an internal combustion engine in addition to the electric vehicle.

  Referring to FIG. 1, vehicle 100 includes a battery B that is a power storage device, a voltage sensor 10, a power control unit (PCU) 40, a motor generator MG, and a control device 30. PCU 40 includes a voltage converter 12, smoothing capacitors C 1 and C 0, a voltage sensor 13, and an inverter 14. Note that the PCU 40 may include only the inverter 14 without providing the voltage converter 12. Vehicle 100 further includes a positive electrode bus PL2 that supplies power to inverter 14 that drives motor generator MG.

  Smoothing capacitor C1 is connected between positive electrode bus PL1 and negative electrode bus SL2. The voltage converter 12 boosts the voltage across the terminals of the smoothing capacitor C1. The smoothing capacitor C0 smoothes the voltage boosted by the voltage converter 12. The voltage sensor 13 detects the voltage VH between the terminals of the smoothing capacitor C0 and outputs it to the control device 30.

  Vehicle 100 further includes system main relay SMRB connected between the positive electrode of battery B and positive electrode bus PL1, and system main relay SMRG connected between the negative electrode of battery B (negative electrode bus SL1) and node N2. Including.

  System main relays SMRB and SMRG are controlled to be in a conductive / non-conductive state in accordance with control signal SE provided from control device 30. The voltage sensor 10 measures the voltage VB between the terminals of the battery B. Although not shown, in order to monitor the charging state of the battery B together with the voltage sensor 10, a current sensor for detecting a current IB flowing through the battery B is provided.

  As the battery B, for example, a secondary battery such as a lead storage battery, a nickel metal hydride battery, or a lithium ion battery, or a large capacity capacitor such as an electric double layer capacitor can be used. The negative electrode bus SL2 extends through the voltage converter 12 to the inverter 14 side.

  Voltage converter 12 is a voltage converter that is provided between battery B and positive electrode bus PL2 and performs voltage conversion. Voltage converter 12 includes a reactor L1 having one end connected to positive electrode bus PL1, IGBT elements Q1, Q2 connected in series between positive electrode bus PL2 and negative electrode bus SL2, and parallel to IGBT elements Q1, Q2, respectively. And diodes D1 and D2 connected to each other.

  Reactor L1 has the other end connected to the emitter of IGBT element Q1 and the collector of IGBT element Q2. The cathode of diode D1 is connected to the collector of IGBT element Q1, and the anode of diode D1 is connected to the emitter of IGBT element Q1. The cathode of diode D2 is connected to the collector of IGBT element Q2, and the anode of diode D2 is connected to the emitter of IGBT element Q2.

  Inverter 14 is connected to positive electrode bus PL2 and negative electrode bus SL2. Inverter 14 converts the DC voltage output from voltage converter 12 into a three-phase AC voltage and outputs the same to motor generator MG driving wheel 2. Inverter 14 returns the electric power generated in motor generator MG to voltage converter 12 along with regenerative braking. At this time, the voltage converter 12 is controlled by the control device 30 so as to operate as a step-down circuit.

  Inverter 14 includes a U-phase arm 15, a V-phase arm 16, and a W-phase arm 17. U-phase arm 15, V-phase arm 16, and W-phase arm 17 are connected in parallel between positive electrode bus PL2 and negative electrode bus SL2.

  U-phase arm 15 includes IGBT elements Q3 and Q4 connected in series between positive electrode bus PL2 and negative electrode bus SL2, and diodes D3 and D4 connected in parallel with IGBT elements Q3 and Q4, respectively. The cathode of diode D3 is connected to the collector of IGBT element Q3, and the anode of diode D3 is connected to the emitter of IGBT element Q3. The cathode of diode D4 is connected to the collector of IGBT element Q4, and the anode of diode D4 is connected to the emitter of IGBT element Q4.

  V-phase arm 16 includes IGBT elements Q5 and Q6 connected in series between positive electrode bus PL2 and negative electrode bus SL2, and diodes D5 and D6 connected in parallel with IGBT elements Q5 and Q6, respectively. The cathode of diode D5 is connected to the collector of IGBT element Q5, and the anode of diode D5 is connected to the emitter of IGBT element Q5. The cathode of diode D6 is connected to the collector of IGBT element Q6, and the anode of diode D6 is connected to the emitter of IGBT element Q6.

  W-phase arm 17 includes IGBT elements Q7, Q8 connected in series between positive electrode bus PL2 and negative electrode bus SL2, and diodes D7, D8 connected in parallel with IGBT elements Q7, Q8, respectively. The cathode of diode D7 is connected to the collector of IGBT element Q7, and the anode of diode D7 is connected to the emitter of IGBT element Q7. The cathode of diode D8 is connected to the collector of IGBT element Q8, and the anode of diode D8 is connected to the emitter of IGBT element Q8.

  Motor generator MG is a three-phase permanent magnet synchronous motor, and one end of each of three stator coils of U, V, and W phases is connected to a neutral point. The other end of the U-phase coil is connected to a line drawn from the connection node of IGBT elements Q3 and Q4. The other end of the V-phase coil is connected to a line drawn from the connection node of IGBT elements Q5 and Q6. The other end of the W-phase coil is connected to a line drawn from the connection node of IGBT elements Q7 and Q8.

  Current sensor 24 detects the current flowing through motor generator MG as motor current value MCRT, and outputs motor current value MCRT to control device 30.

  Control device 30 receives the accelerator opening from accelerator sensor 111 and the set position of the shift lever from shift position sensor 113. Control device 30 further receives a rotational speed of motor generator MG, values of current IB and voltages VB and VH, motor current value MCRT, and activation signal IGON. And the control apparatus 30 controls the voltage converter 12 and the inverter 14 based on such information.

  Specifically, the control signal PWU for instructing voltage boosting to the voltage converter 12, the control signal PWD for instructing voltage step-down, and the shutdown signal instructing prohibition of operation are output.

  Further, control device 30 generates a control signal PWMI for instructing inverter 14 to convert a DC voltage output from voltage converter 12 into an AC voltage for driving motor generator MG, and motor generator MG for power generation. A control signal PWMC for performing a regeneration instruction for converting the AC voltage thus converted into a DC voltage and returning it to the voltage converter 12 side is output.

[Description of cooling system]
Referring again to FIG. 1, vehicle 100 includes a radiator 102, a reservoir tank 106, and a water pump 104 as a cooling system for cooling PCU 40 and motor generator MG.

  The radiator 102, the PCU 40, the reservoir tank 106, the water pump 104, and the motor generator MG are annularly connected in series by a flow path 116.

  The water pump 104 is a pump for circulating cooling water such as antifreeze. Radiator 102 receives cooling water after cooling voltage converter 12 and inverter 14 inside PCU 40 from flow path 116, and cools the received cooling water using a radiator fan (not shown).

  In the vicinity of the cooling water inlet of the PCU 40, a temperature sensor 108 for measuring the cooling water temperature is provided. The cooling water temperature TW is transmitted from the temperature sensor 108 to the control device 30. In addition, a temperature sensor 110 that detects the temperature TC of the voltage converter 12 and a temperature sensor 112 that detects the temperature TI of the inverter 14 are provided inside the PCU 40. As the temperature sensors 110 and 112, a temperature detection element or the like built in the intelligent power module is used.

  Control device 30 generates signal SP for driving water pump 104 based on temperature TC from temperature sensor 110 and temperature TI from temperature sensor 112, and outputs the generated signal SP to water pump 104. To do.

  In the configuration shown in FIG. 1, the temperature sensor 112 is used to detect the flow rate of cooling water that has not been detected in the past or whose estimation accuracy is low. By detecting the flow rate, the abnormality diagnosis of the water pump 104 can be performed accurately, or the water pump 104 can be controlled by feeding back the flow rate.

FIG. 2 is a diagram for explaining the principle of flow rate estimation in the present embodiment.
FIG. 2 shows the configuration of the cooling system extracted from the configuration of the vehicle 100 of FIG. The radiator 102, the PCU 40, the reservoir tank 106, the water pump 104, and the motor generator MG are annularly connected in series by a flow path 116. Water pump 104 sucks the cooling water from reservoir tank 106 and circulates the cooling water toward motor generator MG.

  A temperature sensor 108 for measuring the coolant temperature is provided near the coolant inlet of the PCU 40 as shown in FIG. Cooling water temperature TW is transmitted from temperature sensor 108 to control device (ECU) 30. Further, a temperature sensor for detecting temperatures TI and TC of the power control element is provided inside the PCU 40. As the temperature sensor, a temperature detection element or the like built in the intelligent power module is used.

FIG. 3 is a waveform diagram for explaining the diagnosis timing of the cooling system water pump.
Referring to FIG. 1 and FIG. 3, when an activation instruction is given from the driver by the vehicle start button or the like, the vehicle completes the ECU self-check and enters a ReadyON state. Thereafter, in a state where the vehicle is set to the parking range and stopped at times t1 to t2, control device 30 outputs a torque command to inverter 14 for a short time. This torque command is smaller than the torque command during running after time t3. Therefore, if the parking range is set and the accelerator pedal is not depressed, the torque enough to start the vehicle is not generated.

  The short-time torque command is for generating heat in the power control element (IGBT element or the like) of the inverter, and thus does not have to generate torque. For example, the inverter 14 may be controlled so that only the d-axis current of the inverter flows and the q-axis current does not flow so as not to generate torque.

  When the diagnosis of the operation status of the water pump 104 is completed by time t3 and it is confirmed that the operation status is normal, an acceleration / deceleration instruction such as from the accelerator pedal is given as shown at times t3 to t4. In response, a torque command is generated and the vehicle shifts to a state where it can travel. The time point t3 may be defined as the ReadyON state.

  FIG. 4 is a flowchart for explaining control of the water pump diagnosis time shown in FIG. The processing of this flowchart is called from the main routine and executed when the start switch for starting the vehicle system is set to the ON state.

  Referring to FIGS. 3 and 4, in step S <b> 1, it is determined whether or not a charging / discharging operation using inverter 14 is performed from battery B. If there is no charge / discharge operation, the process proceeds to step S2, and the water pump 104 is diagnosed. Thereby, an environment with little noise suitable for diagnosis of the water pump 104 is ensured. If there is a charge / discharge operation in step S1, for example, if the accelerator is depressed immediately, the water pump 104 is not diagnosed and the next opportunity is awaited, and control is returned to the main routine in step S6.

  Prioritizing the diagnosis of the water pump 104, the shift position after the start switch is prohibited from moving from the parking position or the input of the accelerator pedal is not accepted until the diagnosis of the water pump 104 is completed. May be.

  In step S2, the power control element of the inverter 14 is heated for a short time, and then the flow rate is detected based on the degree to which it is cooled. It is possible to diagnose whether the water pump 104 is operating normally based on the detected flow rate. Even if the flow rate is not estimated, whether or not the water pump 104 is operating normally may be diagnosed by comparing with the degree of cooling when the water pump 104 operates normally.

  In step S3, it is determined whether or not the water pump is normal. If it is determined that the water pump is normal, the process proceeds to step S4, and charge / discharge operation using the inverter 14 from the battery B is permitted. As a result, the vehicle can travel. The detected cooling water amount may be fed back and used for pump control. On the other hand, when it is determined in step S3 that the water pump 104 is not normal, a warning is displayed on a display device, a warning lamp, or the like.

  When the process of step S4 or step S5 ends, control is transferred to the main routine in step S6.

  FIG. 5 is a flowchart for explaining the flow rate determination process used at the time of diagnosis of the water pump in step S2 of FIG. The process of this flowchart is called and executed from the process of the flowchart of FIG. 4 which is the main routine.

  Referring to FIG. 5, the process of this flowchart is started based on an operation for instructing vehicle system activation or vehicle system termination. First, in step S21, the control device 30 determines whether or not the condition that the shift range is set to the P (parking) range and the accelerator pedal is not operated (OFF state) is satisfied. While this condition is not satisfied, the process proceeds to step S37, and control is transferred to the main routine. In the case of a hybrid vehicle, there is a case where the motor inverter is energized in order to start the engine when the battery storage amount is low, so the condition that the battery storage amount does not decrease is added. May be.

  If the condition of step S21 is satisfied, the process proceeds to step S22, where the water temperature Tw at that time is stored as a value Tw0, and the inverter element temperature Ti is stored as a value Ti0.

  Subsequently, in step S23, the command torque is determined from the water temperature-command torque map.

  FIG. 6 is a diagram showing an example of a water temperature-command torque map referred to in step S23 of FIG. In the example of the map shown in FIG. 6, the command torque is set so as to decrease as the water temperature rises.

  Referring to FIG. 5 again, following step S23, in step S24, control device 30 provides command torque determined based on the water temperature to inverter 14 (torque ON). In step S25, the command torque is set to zero again (torque OFF). As described above, the power control element in the inverter generates heat for a short time as shown at times t1 to t2 in FIG.

  In step S25, control device 30 returns the command torque to zero, and simultaneously stores the temperature of the power control element in the inverter at that time as peak temperature Ti1, and stores the time at that time as t1.

FIG. 7 is a diagram for explaining the measurement of the temperature decrease rate.
Referring to FIGS. 5 and 7, the temperature of the power control element of the inverter starts to rise at time t0 in response to setting the inverter torque command to the ON state. The element temperature continues to rise until the inverter torque command is set to the OFF state. At time t1 corresponding to setting the inverter torque command to the OFF state, the element temperature takes the peak value Ti1. This peak value Ti1 and the time t1 at that time are recorded in the internal memory or the like of the control device 30 during the process of step S25.

Subsequently, in step S26, a difference value ΔTi01 between the peak temperature Ti1 and the current inverter element temperature Ti0 is calculated based on the following equation (1).
ΔTi01 = Ti1-Ti0 (1)
In step S27, the specified number m is set, and the counter is further initialized. The counter value n is set to “2”.

The processing from step S28 to step S34 is repeated based on the counter value n.
First, in step S28, control device 30 determines a calculated temperature for the rate of temperature decrease of the power control element of the inverter. When the difference of the calculated temperature for calculating the rate of temperature decrease of the power control element of the inverter corresponding to the counter value n is ΔTi1n, the following equation (2) is obtained.
ΔTi1n = ΔTi01 * (n−1) / n (2)
For example, when n = 2, ΔTi12 = ΔTi01 * 1/2, and when the temperature difference is reduced to half, the first measurement is performed. When n = 3, the temperature difference decreases to 1/3.

Subsequently, in step S29, it is determined whether or not the current temperature has dropped to a temperature Tin represented by the following equation (3).
Tin = Ti1-ΔTi1n (3)
In step S29, times t2, t3, and t4 are measured when the temperature differences ΔTi12, ΔTi13, and ΔTi14 calculated in step S28 decrease from the peak value Ti1, respectively. For example, the times t2 and t3 can be times when the temperature difference becomes 1/2 and 1/3 of ΔTi01, respectively. Although not shown in the flowchart of FIG. 5, a time when the temperature becomes slightly higher (for example, + 2 ° C.) than the initial temperature Ti0 can be set as a measurement point, as at time t4 in FIG.

  Based on the measured time tn and the stored time t1, a time difference Δt1n from time t1 is calculated in step S30. As shown in FIG. 7, time differences Δt12, Δt13, Δt14 corresponding to the temperature differences ΔTi12, ΔTi13, ΔTi14, respectively, are calculated. The calculated value is recorded in an internal memory of the control device 30 or the like.

  Subsequently, in step S31, the flow rate is calculated from the temperature difference ΔTin and time difference Δtin and the descending rate flow rate map.

  FIG. 8 is a diagram illustrating an example of a descending rate flow map. Since the descending rate flow rate map of FIG. 8 is different for each cooling system of the vehicle, a value obtained experimentally in advance is used. Note that the vehicle itself may acquire data when the water pump is normal immediately after factory shipment or inspection, and this may be used as a reference value. In step S31, the obtained flow rate Qn is stored.

  Subsequently, in step S32, it is determined again whether or not the condition of step S21 is continued. This condition is a condition that the shift range is set to the P (parking) range and the accelerator pedal is not operated (OFF state).

  If this condition is not satisfied, the process proceeds to step S35, and the flow rate is calculated based on the measurement results so far. On the other hand, if this condition is still satisfied, the process proceeds to step S33, and measurement data is acquired to further increase the accuracy of the detected flow rate.

  In step S33, the counter value n of the counter set in step S27 is increased by 1. In step S24, it is determined whether or not the counter value is smaller than the number of measurements m set in step S27. When n <m, the processing from step S28 is repeated again, and the acquisition of the data set of the time difference Δt1n and the temperature difference ΔTin is continued.

  If n is equal to m in step S34 and the predetermined number of measurements m has been completed, the process proceeds to step S35.

  In step S35, an average value Qout of the flow rate Qj (j = 2,... M) for the measured number of times is calculated. Then, in step S36, it is determined whether or not an appropriate value Qout is detected as the flow rate corresponding to the command value that is commanded to the water pump 104. Specifically, when the value Qout falls outside the range determined in advance with respect to the command value, it is highly probable that a water pump failure has occurred, and the driver is warned or the vehicle is running. Is restricted or prohibited.

  In step S37 following step S36, control is transferred to the flowchart of FIG. 4, which is the main routine.

  Again, this embodiment will be summarized with reference to FIG. The vehicle diagnosis system of the present embodiment includes a flow path 116 for circulating a liquid medium that cools the inverter 14 of the vehicle, an element temperature sensor 112 that detects the temperature of the power control elements Q3 to Q8 in the inverter 14, and an upper flow path. The power control element in the inverter 14 for diagnosing the operation status of the pump 104 under the condition that the pump 104 for circulating the liquid medium provided in the circuit and the condition that no other drive command is issued to the inverter 14 are satisfied. And a control device 30 for reducing the heat generation of the power control elements Q3 to Q8 after causing Q3 to Q8 to generate heat temporarily and diagnosing the operating state of the pump 104 according to the degree of decrease in the temperature detected by the element temperature sensor 112. .

  Preferably, as shown in the start condition of FIG. 5, the diagnosis execution condition is set within a predetermined period after the system start signal is given to the vehicle (at ReadyON) or after the system stop signal is given to the vehicle. It includes a condition that it is within a predetermined period (when ReadyOFF).

  More preferably, as shown in step S21 of FIG. 5, the diagnosis execution condition further includes a condition that the shift range is set to the parking range (P range) and the accelerator pedal is not operated (accelerator OFF). .

  More preferably, as shown in FIGS. 3 (t1 to t2) and FIG. 7 (t0 to t1), the control device 30 temporarily outputs a command torque to the inverter even when the accelerator pedal is not operated. As a result, the power control elements Q3 to Q8 generate heat.

  More preferably, the vehicle diagnosis system further includes a liquid temperature sensor 108 that detects the temperature of the liquid medium. As shown in step S <b> 23 of FIG. 5 and FIG. 6, the control device 30 determines the magnitude of the command torque based on the temperature Tw detected by the liquid temperature sensor 108.

  According to the present invention, since it is possible to detect the flow rate of the coolant medium more accurately than in the past, it is possible to accurately determine the abnormality of the water pump.

  More specifically, by detecting the descending rate of the inverter element temperature, the amount of cooling water can be determined from a map showing the relationship between the “decreasing rate and the flow rate” without adding a new flow rate sensor.

  In addition, in the case of a hybrid vehicle before or after the start of traveling, a pump diagnosis is performed when the engine is stopped and when the vehicle is stopped, thereby removing disturbances that cause an increase in inverter element temperature and enabling accurate flow rate detection.

  Furthermore, by changing the magnitude of the inverter command torque based on the coolant temperature, the inverter element can be raised as a heat source while avoiding destruction of the inverter element.

  In addition, by measuring the descent rate a plurality of times, the coolant flow rate can be calculated with high accuracy from a map showing the relationship between the “descent rate and the flow rate”. In this case, the amount of cooling water is calculated from the descent rate measured before that even if the vehicle starts running or the engine starts before measuring the specified number of times (some hybrid vehicles use an inverter for the motor to start the engine). be able to.

  The embodiment disclosed this time should be considered as illustrative in all points and not restrictive. The scope of the present invention is defined by the terms of the claims, rather than the description above, and is intended to include any modifications within the scope and meaning equivalent to the terms of the claims.

  10, 13 Voltage sensor, 12 Voltage converter, 14 Inverter, 24 Current sensor, 30 Control device, 100 Vehicle, 102 Radiator, 104 Water pump, 106 Reservoir tank, 108, 110, 112 Temperature sensor, 111 Axel sensor, 113 Shift position Sensor, 116 flow path, B battery, C1, C0 smoothing capacitor, D1-D8 diode, L1 reactor, MG motor generator, PL1, PL2 positive bus, Q1-Q8 power control element, SL1, SL2 negative bus, SMRB, SMRG System main relay.

Claims (5)

A flow path for circulating a liquid medium for cooling the inverter of the vehicle;
An element temperature sensor for detecting the temperature of the power control element in the inverter;
A pump for circulating the liquid medium provided on the flow path;
The power control element after the power control element in the inverter is temporarily heated for diagnosis of the operation status of the pump under a condition that satisfies a diagnosis execution condition in which no other drive command is issued to the inverter And a diagnostic device for diagnosing the operating state of the pump according to the degree of decrease in the temperature detected by the element temperature sensor.   The vehicle according to claim 1, wherein the diagnosis execution condition includes a condition that a predetermined period after a system start signal is given to the vehicle or a predetermined period after a system stop signal is given to the vehicle. Diagnostic system.   The vehicle diagnosis system according to claim 2, wherein the diagnosis execution condition further includes a condition that a shift range is set to a parking range and an accelerator pedal is not operated.   The vehicle diagnosis system according to claim 3, wherein the diagnosis device causes the power control element to generate heat by temporarily outputting a command torque to the inverter even when the accelerator pedal is not operated. A liquid temperature sensor for detecting the temperature of the liquid medium;
The vehicle diagnosis system according to claim 4, wherein the diagnosis device determines the magnitude of the command torque based on a temperature detected by the liquid temperature sensor.

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