Relay diagnostic device for vehicle

Abstract

The invention provides a vehicle relay diagnostic device which suppresses the complicated diagnosis of the malfunction of a plurality of relays. A vehicle relay diagnostic device includes: a first detection unit that detects a voltage of a converter; a second detection unit that detects a voltage that is a potential difference between a first electric wire between the first relay and the converter and a second electric wire between the second relay and the power storage unit; a third detection unit that detects a voltage between terminals of the first relay; and a control system. The processing performed by the control system includes: a step of matching the voltage of the power storage unit with the voltage of the converter; a step of diagnosing that the first relay is in a disconnection clamping stagnation abnormity; outputting a closing signal to the second relay; a step of diagnosing that the second relay is in a disconnection clamping stagnation abnormity; a step of diagnosing that the second relay is in a closed clamping stagnation abnormity; and a step of diagnosing that the first relay is in the closing clamping stagnation abnormity.

Description

Technical Field

[0001] The invention relates to a relay diagnostic device for a vehicle. Background Art

[0002] A diagnosis is made to check whether a relay installed in a vehicle is welded (see Patent Documents 1, 2, and 3). In addition, a vehicle is proposed that is not provided with a pre-charging circuit for suppressing the welding of the relay (see Patent Documents 1 and 2).

[0003] Prior art literature Patent Literature Patent Document 1: Japanese Patent Application Publication No. 2020-099129 Patent Document 2: Japanese Patent Application Publication No. 2007-295699 Patent Document 3: Japanese Patent Application Publication No. 2011-055631 Summary of the invention

[0004] Technical issues When diagnosing whether or not multiple relays have malfunctions, in the configurations of Patent Documents 1 and 2, it is necessary to turn on and off the converter at least once in diagnosing one relay. That is, it is necessary to turn on and off the converter multiple times in diagnosing malfunctions of each relay, and there is room for improvement.

[0005] An object of the present invention is to prevent the diagnosis of malfunctions in a plurality of relays from becoming complicated.

[0006] Technical Solution A vehicle relay diagnostic device according to one embodiment diagnoses the operation of the first relay and the operation of the second relay in a vehicle in which a power storage unit and a converter are connected by a first electric wire and a second electric wire, the first electric wire being provided with a first relay, and the second electric wire being provided with a second relay having a different polarity from the first electric wire. The vehicle relay diagnostic device includes: a first detection unit that detects a voltage of the converter; a second detection unit that detects a voltage that is a potential difference between the first electric wire and the second electric wire, the first electric wire being between the first relay and the converter, and the second electric wire being between the second relay and the power storage unit; a third detection unit that detects a voltage between terminals of the first relay; and a control system that includes a processor and a memory and controls the converter, the first relay, and the second relay. The processing executed by the control system includes: a step of matching the voltage of the converter with the voltage of the power storage unit; a step of outputting a closing signal (ON signal) to the first relay when the converter is in an on state; a step of diagnosing that the first relay is in an open stuck abnormality (OFF stuck abnormality) when both the voltage detected by the second detection unit and the voltage between the terminals detected by the third detection unit cannot be detected; a step of outputting a closing signal to the second relay when the converter is in an on state and the first relay is in an on state; a step of diagnosing that the second relay is in an open stuck abnormality when a closing signal (OFF signal) is output to the converter and the voltage of the first detection unit decreases; a step of diagnosing that the second relay is in an open stuck abnormality (ON stuck abnormality) when the voltage of the first detection unit does not decrease after an opening signal (OFF signal) is output to the second relay when the converter is in an off state and the first relay is in an on state; and a step of diagnosing that the first relay is in an open stuck abnormality when the voltage between the terminals of the third detection unit is 0 (V) after an opening signal is output to the first relay when the converter is in an off state and the second relay is in an off state.

[0007] Technical Effects In the vehicle relay diagnosis device of one embodiment, the control system executes each step so as to turn on and off the converter once each, thereby preventing the diagnosis of malfunctions of a plurality of relays from becoming complicated. BRIEF DESCRIPTION OF THE DRAWINGS

[0008] Figure 1 FIG. 1 is a diagram showing a hybrid vehicle including the relay diagnostic device according to the first embodiment.

[0009] Figure 2This is a block diagram showing a schematic configuration of a hybrid vehicle including the relay diagnostic device according to the first embodiment.

[0010] Figure 3 This is a block diagram showing an example of the functional configuration of the control system.

[0011] Figure 4 This is a diagram showing an example of a basic structure of a control unit.

[0012] Figure 5 This is a graph showing the switching timing of closing and opening of the system main relay of the hybrid vehicle according to the first embodiment and each voltage detected at each timing.

[0013] Figure 6 This is a flowchart showing the first half of the execution procedure of the relay diagnosis device according to the first embodiment and the second embodiment.

[0014] Figure 7 This is a flowchart showing the second half of the execution procedure of the relay diagnostic device according to the first embodiment and the second embodiment.

[0015] Figure 8 This is a flowchart showing an example of the execution procedure of the relay diagnostic device according to the second embodiment.

[0016] Fig. 9 This is a block diagram showing the internal structure of a hybrid vehicle including a relay diagnostic device according to a modified example.

[0017] Fig.10 This is a graph showing the switching timing of closing and opening of a system main relay of a hybrid vehicle according to a modification and each voltage detected at each timing.

[0018] Explanation of symbols 10…hybrid vehicle (an example of a vehicle), 26…main battery (an example of a power storage unit), 32…DCDC converter (an example of a converter), 33…first electric wire, 35…second electric wire, 36…positive electrode side relay (an example of a first relay), 38…negative electrode side relay (an example of a second relay), 40…relay diagnostic device (an example of a vehicle relay diagnostic device), 42…first voltage sensor (an example of a first detection unit), 44…second voltage sensor (an example of a second detection unit), 46…third voltage sensor (an example of a third detection unit), 50…control system, 73…processor, 74…memory, 90…relay diagnostic device (an example of a vehicle relay diagnostic device), V1…voltage, V2…voltage, VA…voltage, VB…voltage, VC…voltage DETAILED DESCRIPTION

[0019] Hereinafter, the first embodiment, the second embodiment and the modified example will be described in detail based on the drawings. It should be noted that in the following description, the same or substantially the same configurations and elements are denoted by the same reference numerals, and repeated description is omitted.

[0020] [First embodiment] Figure 1 1 is a diagram showing a hybrid vehicle 10 having a relay diagnostic device 40 according to a first embodiment. The hybrid vehicle 10 is an example of a vehicle. The hybrid vehicle 10 is equipped with a powertrain 16 including an engine 12 and a transmission 14. The powertrain 16 has an output shaft 19. The output shaft 19 is connected to a rear wheel 29 via a propeller shaft 21 and a rear differential 23.

[0021] In addition, a front differential 25 is assembled to the transmission 14. A front wheel 27 is connected to the front differential 25. It should be noted that the hybrid vehicle 10 may be in any of a series mode, a parallel mode, and a series-parallel mode. The powertrain 16 is a powertrain for all-wheel drive, but is not limited thereto, and a power unit for front-wheel drive or rear-wheel drive may also be used.

[0022] Figure 2 It is a block diagram showing a schematic configuration of the hybrid vehicle 10 . Figure 3 : is a block diagram showing an example of the functional configuration of the control system 50 . Figure 4 It is a diagram showing a basic configuration of each control unit included in the control system 50 .

[0023] like Figure 2 As shown, the hybrid vehicle 10 includes an engine 12 , a transmission 14 , a running motor 18 , an inverter 24 , a main battery 26 , a sub-battery 28 , a DCDC converter 32 , and a system main relay 34 . DC is an abbreviation for Direct Current. In addition, the hybrid vehicle 10 includes a relay diagnostic device 40 .

[0024] The hybrid vehicle 10 can switch between an HEV (Hybrid Electric Vehicle) driving mode in which the vehicle is driven by the power of the engine 12 and the driving motor 18 , and an EV (Electric Vehicle) driving mode in which the vehicle is driven by the power of the driving motor 18 with the engine 12 stopped.

[0025] <Engine> The engine 12 is an internal combustion engine that uses gasoline or the like as fuel to generate power. The engine 12 can output power for driving the front wheels 27 and the rear wheels 29 of the hybrid vehicle 10. The crankshaft, which is the output shaft of the engine 12, is connected to the transmission 14 via a torque converter or the like. The power output from the engine 12 is speed-changed by the transmission 14 and transmitted to the front wheels 27 and the rear wheels 29.

[0026] The engine 12 is provided with an ISG (Integrated Starter Generator) 13. The output shaft of the ISG 13 is connected to the crankshaft of the engine 12 via a gear. The power output from the ISG 13 is transmitted to the crankshaft of the engine 12. As an example, the ISG 13 is connected to a sub-battery 28. The ISG 13 generates power using the power supplied from the sub-battery 28. In addition, the ISG 13 can generate power using the power output from the engine 12. The sub-battery 28 can be charged using the power generated by the ISG 13.

[0027] <Transmission, etc.> The transmission 14 includes a travel motor 18 and the like. The travel motor 18 is an electric motor. The travel motor 18 is connected to a main battery 26 via an inverter 24. The travel motor 18 is capable of power operation and regenerative operation. During regenerative operation, the travel motor 18 converts kinetic energy into electrical energy and charges the main battery 26 via the inverter 24. In addition, the travel motor 18 generates power using the electric power supplied from the main battery 26 via the inverter 24.

[0028] <Main battery> The main battery 26 is an example of a storage unit that stores electric power supplied to the travel motor 18. Specifically, the main battery 26 is a battery having a voltage higher than that of the sub-battery 28 (200 (V) as an example). The voltage of the main battery 26 is detected by a sensor 26A. As an example, a secondary battery such as a lithium-ion battery or a nickel-metal hydride battery is used for the main battery 26.

[0029] The main battery 26 is connected to each device in the hybrid vehicle 10 via the DCDC converter 32. Thus, in the hybrid vehicle 10, the power stored in the main battery 26 can be stepped down by the DCDC converter 32 and supplied to each device. A system main relay 34 described below is provided between the main battery 26 and the DCDC converter 32.

[0030] <Sub-battery> The sub-battery 28 is connected to the main battery 26 via the DCDC converter 32, the first wire 33, and the second wire 35. The sub-battery 28 is a battery having a voltage lower than that of the main battery 26 (12V as an example). The sub-battery 28 is charged with power generated by the ISG 13. The power of the sub-battery 28 is supplied to the DCDC converter 32. As an example, the sub-battery 28 uses a secondary battery such as a lead storage battery or a lithium ion battery.

[0031] <DCDC Converter> The DCDC converter 32 is an example of a converter connected to the main battery 26 via the first electric wire 33, the second electric wire 35, and the system main relay 34. The DCDC converter 32 changes the voltage of the sub-battery 28. Specifically, the DCDC converter 32 boosts the voltage of the sub-battery 28. The DCDC converter 32 can output a voltage equivalent to the voltage of the main battery 26.

[0032] <<First Electric Wire>> The first electric wire 33 includes a wiring 33A and a wiring 33B. The wiring 33A connects the DCDC converter 32 to a terminal A of the system main relay 34, which will be described later. The wiring 33B connects a terminal B of the system main relay 34, which will be described later, to the main battery 26. The first electric wire 33 corresponds to the wiring on the positive electrode side. One end of the wiring 41 is connected to the wiring 33A. The other end of the wiring 41 is connected to the converter 24.

[0033] <<Second electric wire>> The second electric wire 35 includes a wiring 35A and a wiring 35B. The second electric wire 35 corresponds to the wiring on the negative electrode side. That is, the polarity of the second electric wire 35 is different from the polarity of the first electric wire 33. The wiring 35A connects the DCDC converter 32 to a terminal C of the system main relay 34 described later. The wiring 35B connects a terminal D of the system main relay 34 described later to the main battery 26. One end of the wiring 43 is connected to the wiring 35A. The other end of the wiring 43 is connected to the converter 24. In this way, in the hybrid vehicle 10, the first electric wire 33 and the second electric wire 35 connect the main battery 26 and the DCDC converter 32.

[0034] <System main relay> The system main relay 34 is capable of disconnecting and connecting the electrical connection between the main battery 26 and the DCDC converter 32 on both the positive side and the negative side. The system main relay 34 becomes an open state (disconnected state) when the hybrid vehicle 10 stops. In addition, the system main relay 34 becomes a closed state (connected state) when the hybrid vehicle 10 starts and travels. In the following description, the action of changing the system main relay 34 to a closed state is referred to as a closing action (ON action), and the action of changing the system main relay 34 to an open state is referred to as a disconnecting action (OFF action). Specifically, the system main relay 34 has a positive side relay 36 and a negative side relay 38. It should be noted that "SMRP" recorded in the figure is an abbreviation for the positive side relay 36. "SMRN" is an abbreviation for the negative side relay 38.

[0035] <<Positive side relay>> The positive electrode side relay 36 is an example of a first relay having a terminal A and a terminal B. The positive electrode side relay 36 is provided on the first electric wire 33 between the main battery 26 and the DCDC converter 32. The closing and opening operations of the positive electrode side relay 36 are controlled by a control system 50 described later.

[0036] <<Negative side relay>> The negative electrode side relay 38 is an example of a second relay having a terminal C and a terminal D. The negative electrode side relay 38 is provided on the second electric wire 35 between the main battery 26 and the DCDC converter 32. The closing operation and the opening operation of the negative electrode side relay 38 are controlled by a control system 50 described later.

[0037] <Relay diagnostic device> The relay diagnostic device 40 is an example of a relay diagnostic device for a vehicle. The relay diagnostic device 40 diagnoses the operation of each of the positive-side relay 36 and the negative-side relay 38 within a time TP of a trip described later. Specifically, the relay diagnostic device 40 diagnoses whether each of the positive-side relay 36 and the negative-side relay 38 has malfunction. It should be noted that in this embodiment, "malfunction" refers to "closing stuck abnormality and opening stuck abnormality".

[0038] The "stuck-closed abnormality" means that the positive-side relay 36 and the negative-side relay 38 cannot be turned off even if the control system 50 described later outputs an off signal to the positive-side relay 36 and the negative-side relay 38. For example, the positive-side relay 36 and the negative-side relay 38 are welded to the terminals.

[0039] The "opening stuck abnormality" means that the positive side relay 36 and the negative side relay 38 cannot be closed even if the control system 50 outputs a closing signal to the positive side relay 36 and the negative side relay 38. For example, there may be a defect such as poor contact in the circuit that causes the positive side relay 36 and the negative side relay 38 to operate.

[0040] The relay diagnosis device 40 includes a first voltage sensor 42, a second voltage sensor 44, a third voltage sensor 46, and a control system 50. The control system 50 also serves as a control system for the entire hybrid vehicle 10.

[0041] <<First voltage sensor>> The first voltage sensor 42 is an example of a first detection unit. The first voltage sensor 42 detects the voltage on the main battery 26 side of the DCDC converter 32. Specifically, the first voltage sensor 42 is connected to the wiring 33A and the wiring 35A near the input and output terminals of the DCDC converter 32. Then, the voltage detected by the first voltage sensor 42 is set to VA.

[0042] <<Second voltage sensor>> The second voltage sensor 44 is an example of a second detection unit. The second voltage sensor 44 is connected to the wiring 33A between the positive-side relay 36 and the DCDC converter 32, and is connected to the wiring 35B between the negative-side relay 38 and the main battery 26. That is, the second voltage sensor 44 detects a voltage that is a potential difference between the first wire 33 between the positive-side relay 36 and the DCDC converter 32 and the second wire 35 between the negative-side relay 38 and the main battery 26. Thereafter, the voltage detected by the second voltage sensor 44 is set as VB.

[0043] <<Third voltage sensor>> The third voltage sensor 46 is an example of a third detection unit. The third voltage sensor 46 detects the voltage between the terminals of the positive-side relay 36. That is, the third voltage sensor 46 detects the voltage between the terminals A and B. Then, the voltage between the terminals detected by the third voltage sensor 46 is set as VC.

[0044] <<Control System>> The control system 50 includes a processor 73 and a main memory 74. The main memory 74 is an example of a memory. The control system 50 controls the operations of the DCDC converter 32, the positive-side relay 36, and the negative-side relay 38. The control system 50 is activated based on the operation of the switch by the driver. When the driver presses the switch while stepping on the brake pedal, the control system 50 controls the hybrid vehicle 10 to a drivable state (Ready ON).

[0045] On the other hand, when the driver depresses the switch while the hybrid vehicle 10 is controlled to be in the drivable state, the control system 50 controls the hybrid vehicle 10 to be in the stopped state (Ready OFF).

[0046] like Figure 2 and Figure 5 As shown in the figure, in this embodiment, the period from when the DCDC converter 32 is turned on to when the diagnosis in the relay diagnostic device 40 is completed is called "one stroke". In the case of this embodiment, the time TP from time t1 to time t9 is equivalent to the time required for one stroke. In one stroke, the opening action (ON action) and closing action (OFF action) of the DCDC converter 32 are each performed once. It should be noted that DCDC on and DCDC off in the figure represent the opening and closing of the DCDC converter 32.

[0047] The time when the diagnosis in the relay diagnostic device 40 is completed refers to the time when the diagnosis of whether there is a malfunction (closing stuck abnormality and opening stuck abnormality) in each of the positive side relay 36 and the negative side relay 38 is completed. That is, the relay diagnostic device 40 completes the diagnosis of the operation of the system main relay 34 within one stroke. It should be noted that hereinafter, the situation of having at least one of the closing stuck abnormality and the opening stuck abnormality is sometimes collectively referred to and recorded as "malfunction".

[0048] The time when the hybrid vehicle 10 changes to a drivable state is t4, and the time when the hybrid vehicle 10 changes to a stopped state is t5. The time t4 is a time later than the time t3 when the closing signal is sent to the negative-side relay 38. The time t5 is a time before the time t6 when the DCDC converter 32 is turned off and a time later than the time t4.

[0049] like Figure 3 As shown, the control system 50 includes an information acquisition portion 52 , a motor control unit 54 , an engine control unit 56 , a relay control unit 58 , a converter control unit 62 , and a diagnosis unit 64 .

[0050] <<<Information Acquisition Department>>> Information acquisition unit 52 acquires various information used in processing performed by control system 50. Information acquisition unit 52 outputs the acquired information to motor control unit 54, engine control unit 56, relay control unit 58, converter control unit 62, and diagnosis unit 64.

[0051] <<<Motor control unit>>> like Figure 2 and Figure 3 As shown, the motor control unit 54 controls the operation of the travel motor 18. For example, the motor control unit 54 controls the supply of power between the travel motor 18 and the main battery 26 by controlling the operation of the switching element of the inverter 24. Thus, the motor control unit 54 can control the generation of power and electricity by the travel motor 18.

[0052] <<<Engine Control Unit>>> The engine control unit 56 controls the operation of the engine 12. For example, the engine control unit 56 controls the throttle opening, ignition timing, fuel injection amount, etc. by controlling the operation of each part of the engine 12. Thus, the engine control unit 56 can control the output of the engine 12. In addition, the engine control unit 56 controls the operation of the ISG 13. Specifically, the engine control unit 56 can control the restart of the engine 12 by the ISG 13 by controlling the supply of power from the sub-battery 28 to the ISG 13.

[0053] <<<Relay control unit>>> The relay control unit 58 controls the closing action (closing action) and the opening action (opening action) of the system main relay 34. The closing action of the system main relay 34 refers to the action of switching the positive side relay 36 and the negative side relay 38 from opening to closing. The opening action of the system main relay 34 refers to the action of switching the positive side relay 36 and the negative side relay 38 from closing to opening.

[0054] When performing a closing operation of the system main relay 34 , the relay control unit 58 transmits a closing signal to the system main relay 34 . When performing an opening operation of the system main relay 34 , the relay control unit 58 transmits an opening signal to the system main relay 34 .

[0055] <<<Converter control unit>>> The converter control unit 62 controls the operation of the DCDC converter 32. Specifically, the converter control unit 62 controls the supply of electric power between the main battery 26 and the sub-battery 28 by controlling the operation of the switching element of the DCDC converter 32.

[0056] <<<Diagnosis Unit>>> The diagnosis unit 64 diagnoses whether there is malfunction in the system main relay 34. Specifically, the diagnosis unit 64 diagnoses whether there is malfunction in the positive electrode side relay 36 and whether there is malfunction in the negative electrode side relay 38. It should be noted that, as an example, the diagnosis result of the diagnosis unit 64 is notified to the driver by lighting a lamp provided on the instrument panel of the hybrid vehicle 10.

[0057] like Figure 4 As shown, motor control unit 54, engine control unit 56, relay control unit 58, converter control unit 62 and diagnosis unit 64 have microcontroller 72 including processor 73, main memory 74 and the like. Main memory 74 stores a predetermined program.

[0058] The processor 73 and the main memory 74 are connected in a manner that they can communicate with each other. The processor 73 executes the program by reading a predetermined program from the main memory 74, expanding the predetermined program and executing it. It should be noted that a plurality of processors 73 may be incorporated into the microcontroller 72. In addition, a plurality of main memories 74 may be incorporated into the microcontroller 72.

[0059] The motor control unit 54, the engine control unit 56, the relay control unit 58, and the converter control unit 62 include an input circuit 76, a drive circuit 77, a communication circuit 78, an external memory 79, and a power supply circuit 81. The diagnosis unit 64 includes an input circuit 76, a communication circuit 78, an external memory 79, and a power supply circuit 81. The input circuit 76 converts signals input from various sensors into signals that can be input to the microcontroller 72. The drive circuit 77 generates drive signals for various devices including the aforementioned engine 12 based on the signals output from the microcontroller 72.

[0060] The communication circuit 78 converts the signal output from the microcontroller 72 into a communication signal to other control units. The communication circuit 78 is connected to other control units via an in-vehicle network 83 such as a CAN (Controller Area Network) so that they can communicate with each other. In addition, the communication circuit 78 converts the communication signal received from other control units into a signal that can be input to the microcontroller 72.

[0061] The power supply circuit 81 supplies power supply voltage to the microcontroller 72, the input circuit 76, the drive circuit 77, the communication circuit 78, the external memory 79, etc. The external memory 79 is composed of a nonvolatile memory, etc. The external memory 79 stores programs and various data.

[0062] exist Figure 2In the hybrid vehicle 10 shown, the control system 50 can execute a plurality of steps for diagnosing the system main relay 34. Specifically, the control system 50 outputs an ON signal to the DCDC converter 32 when the positive-side relay 36 and the negative-side relay 38 are in a disconnected state (open circuit state). Furthermore, the control system 50 can execute a step of matching the voltage VA of the DCDC converter 32 with the voltage of the main battery 26.

[0063] The control system 50 outputs a closing signal to the positive-side relay 36 when the DCDC converter 32 is turned on. Furthermore, when the control system 50 cannot detect both the voltage VB of the second voltage sensor 44 and the voltage VC of the third voltage sensor 46, it can execute a step of diagnosing that the positive-side relay 36 is in an abnormal state of being stuck in disconnection. It should be noted that "a case where the voltage cannot be detected" means a case where the resistance value becomes infinite, which means a case where the tester becomes out of range.

[0064] The control system 50 outputs a closing signal to the negative-side relay 38 after outputting a closing signal when the DCDC converter 32 is turned on and the positive-side relay 36 is closed, and then outputs a closing signal to the DCDC converter 32. In addition, when the voltage VA of the first voltage sensor 42 decreases, the control system 50 can perform a step of diagnosing that the negative-side relay 38 is in an abnormal state of being stuck in the open state.

[0065] The control system 50 maintains the DCDC converter 32 in a closed state and the positive-side relay 36 in a closed state. In addition, the control system 50 can perform the following steps: when the voltage VA of the first voltage sensor 42 does not decrease after the disconnection signal is output to the negative-side relay 38, the control system 50 is able to diagnose that the negative-side relay 38 is in a closed stuck abnormality.

[0066] The control system 50 turns off the DCDC converter 32 and maintains the negative electrode relay 38 in the open state. Furthermore, the control system 50 can diagnose that the positive electrode relay 36 is stuck closed when the voltage VC is 0 (V) after the open signal is output to the positive electrode relay 36.

[0067] [Function of the first embodiment] <Relay diagnostic control: Flowchart> Next, the execution procedure of the relay (system main relay 34 ) diagnosis control will be described. Figure 6 and Figure 7 This is a flowchart showing an example of the execution procedure of the relay diagnosis control. Figure 6 and Figure 7The flowchart shown is connected using the terminals A to E. The terminal F is used in the second embodiment described later. Figure 6 and Figure 7 Each step of the relay control shown is executed by the processor 73 constituting the control system 50. Figures 1 to 5 , and omit the recording of individual figure numbers.

[0068] like Figure 6 As shown, the control system 50 proceeds to step S10, and outputs an on signal to the DCDC converter 32 while the positive-side relay 36 and the negative-side relay 38 are in the off state. Then, the control system 50 proceeds to step S12.

[0069] In step S12, the control system 50 adjusts the voltage VA of the DCDC converter 32 to match the voltage of the main battery 26 based on the voltage of the main battery 26 detected by the sensor 26A. Then, the control system 50 moves to step S14.

[0070] In step S14, the control system 50 outputs a closing signal to the positive electrode side relay 36 while the DCDC converter 32 is in the on state. Then, the control system 50 shifts to step S16.

[0071] In step S16, the control system 50 determines whether both the voltage VB and the voltage VC cannot be detected. For example, when at least one of the voltage VB and the voltage VC can be detected (S16: Yes), such as when VB=V2 and VC=0 (V), the control system 50 proceeds to step S18. When both the voltage VB and the voltage VC cannot be detected (S16: No), the control system 50 proceeds to step S28.

[0072] In step S18 , the control system 50 outputs a closing signal to the negative-side relay 38 while the DCDC converter 32 is in the on state and the positive-side relay 36 is in the closed state. Then, the control system 50 shifts to step S20 .

[0073] In step S20, control system 50 outputs a shutdown signal to DCDC converter 32, and determines whether voltage VA has not decreased relative to voltage V1. If voltage VA has not decreased relative to voltage V1 (S20: Yes), the process proceeds to step S22. If voltage VA has decreased relative to voltage V1 (S20: No), the process proceeds to step S30.

[0074] In step S22, the control system 50 outputs an OFF signal to the negative electrode side relay 38, and determines whether the voltage VA is lower than the voltage V1. If the voltage VA is lower than the voltage V1 (S22: Yes), the process proceeds to step S24. If the voltage VA is not lower than the voltage V1 (S22: No), the process proceeds to step S32.

[0075] like Figure 7 As shown, in step S24, the control system 50 outputs an OFF signal to the positive electrode side relay 36 to determine whether the voltage VC cannot be detected or the voltage VC is 0 (V). If the voltage VC cannot be detected (S24: Yes), the process proceeds to step S26. If the voltage VC is 0 (V) (S24: No), the process proceeds to step S34.

[0076] In step S26, the control system 50 displays the diagnosis result of whether the system main relay 34 (positive side relay 36 and negative side relay 38) has no malfunction. For example, the display may be performed by lighting a lamp indicating the good state of the relay provided in a part of the instrument panel, or the touch panel may display that the operation is good. Then, the program is terminated. The diagnosis result of whether the system main relay 34 has malfunction is recorded in the external memory 79 as the diagnosis information.

[0077] In step S28, the control system 50 displays the diagnosis result that the positive-side relay 36 is in the off-stuck abnormal state, and records the diagnosis result in the external memory 79. Then, the program ends. The method for displaying the diagnosis result may be the same as that in step S26.

[0078] In step S30, the control system 50 displays the diagnosis result that the negative-side relay 38 is in the off-stuck abnormal state, and records the diagnosis result in the external memory 79. Then, the program ends. The method for displaying the diagnosis result may be the same as that in step S26.

[0079] In step S32, the control system 50 displays the diagnosis result that the negative-side relay 38 is in the state of abnormal stuck closing, and records the diagnosis result in the external memory 79. Then, the program ends. The method for displaying the diagnosis result may be the same as that in step S26.

[0080] In step S34, the control system 50 displays the diagnosis result that the positive-side relay 36 is in the closed stuck abnormal state, and records the diagnosis result in the external memory 79. Then, the program ends. The method for displaying the diagnosis result may be the same as that in step S26.

[0081] exist Figure 5The closed state and the open state of the system main relay 34 at each time, and the detected voltages VA, VB, and VC are shown. Figure 1 , Figure 2 , Figure 3 and Figure 4 , and omit the recording of individual figure numbers.

[0082] about Figure 5 The time intervals from time t1 to time t9 shown in the figure are examples and are not limited to the time shown in the figure. It should be noted that there is a time lag from when the control system 50 sends a control signal to the controlled object to when the controlled object starts to operate. Figure 5 This time lag is omitted.

[0083] Figure 5 The curve G1 shown shows the timing of sending the closing signal and the opening signal to the positive electrode side relay 36. That is, the curve G1 does not show whether the positive electrode side relay 36 is in the closed state or in the open state.

[0084] The curve G2 shows the timing of sending the closing signal and the opening signal to the negative-electrode-side relay 38. That is, the curve G2 does not show whether the negative-electrode-side relay 38 is in the closed state or in the open state.

[0085] Curve G3 represents the voltage VA detected by the first voltage sensor 42. Curve G6 represents the voltage VB detected by the second voltage sensor 44. Curve G7 represents the voltage VC detected by the third voltage sensor 46. Figure 5 In FIG. 1 , the curves G4 and G5 indicated by the dotted lines are curves showing different behaviors from the curve G3 .

[0086] exist Figure 5 In FIG. 1 , the area SA, area SB, area SC, and area SD indicated by diagonal lines are areas where voltage cannot be detected.

[0087] like Figure 5 As shown, until just before time t1, the positive side relay 36 and the negative side relay 38 are in the open state. The DCDC converter 32 is in the closed state. In addition, the voltage VA, the voltage VB, and the voltage VC cannot be detected. Here, when the voltage VC=0 (V) during the period until time t2 (the case of the dotted line), it can be seen that the positive side relay 36 is in a closed stuck abnormal state. In other words, it can be seen that the positive side relay 36 is in a state where the opening action cannot be performed.

[0088] At time t1, when DCDC converter 32 is turned on, voltage VA rises to voltage V1. When positive-side relay 36 does not have a stuck-closed abnormality, voltage VB and voltage VC cannot be detected.

[0089] At time t2, when a closing signal is sent to the positive-side relay 36, if the operation of the positive-side relay 36 is normal, the state of the positive-side relay 36 becomes a closed state. The voltage VA is the voltage V1. The voltage VB rises to the voltage V2. The voltage VC is 0 (V). Here, when the voltage VB and the voltage VC cannot be detected, it can be known that the positive-side relay 36 is in a state of abnormal opening stuck. In other words, it can be known that the positive-side relay 36 is in a state where the closing action cannot be performed.

[0090] At time t3, when a closing signal is sent to the negative-side relay 38, if the operation of the negative-side relay 38 is normal, the state of the negative-side relay 38 becomes the closed state. The voltage VA is the voltage V1. The voltage VB is the voltage V2. The voltage VC is 0 (V).

[0091] At time t6, DCDC converter 32 is turned off. Here, when voltage VA decreases as shown in curve G4, negative electrode side relay 38 is in an abnormal state of being stuck in opening. In other words, negative electrode side relay 38 is in a state where closing operation cannot be performed.

[0092] At time t7, when a disconnection signal is sent to the negative-pole side relay 38, if the operation of the negative-pole side relay 38 is normal, the state of the negative-pole side relay 38 becomes the disconnected state. At this time, the voltage VA decreases relative to the voltage V1. The voltage VB is the voltage V2. The voltage VC is 0 (V). Here, when the voltage VA is maintained at the voltage V1 as shown in the curve G5, it can be seen that the negative-pole side relay 38 is in a closed stuck abnormal state. In other words, it can be seen that the negative-pole side relay 38 is in a state where the disconnection action cannot be performed.

[0093] At time t8, when a disconnection signal is sent to the positive-side relay 36, if the operation of the positive-side relay 36 is normal, the state of the positive-side relay 36 changes to the disconnected state. At this time, the voltage VA remains in a state lower than the voltage V1. The voltage VB is the voltage V2. The voltage VC cannot be detected. Here, when the voltage VC is 0 (V), it can be known that the positive-side relay 36 is in a state of abnormal closed stuck.

[0094] <Summary of the First Embodiment> As described above, in the relay diagnostic device 40, the control system 50 outputs a closing signal to the positive-side relay 36. Furthermore, when the relay diagnostic device 40 cannot detect both the voltage VB and the voltage VC, it is diagnosed that the positive-side relay 36 is in a state of an open stuck abnormality. After the control system 50 outputs a closing signal to the negative-side relay 38, it stops the operation of the DCDC converter 32, and when the voltage VA decreases, it is diagnosed that the negative-side relay 38 is in a state of an open stuck abnormality.

[0095] After the control system 50 outputs an opening signal to the negative-side relay 38, if the voltage VA does not decrease, the control system 50 diagnoses that the negative-side relay 38 is in a state of abnormal stuck closing. After the control system 50 outputs an opening signal to the positive-side relay 36, if the voltage VC is 0 (V), the control system 50 diagnoses that the positive-side relay 36 is in a state of abnormal stuck closing.

[0096] In this way, the relay diagnostic device 40 executes each step in such a manner that the DCDC converter 32 is turned on and off once in one diagnosis. In other words, the relay diagnostic device 40 diagnoses whether the positive-side relay 36 and the negative-side relay 38 have malfunctions in one stroke. In this way, in the relay diagnostic device 40, compared with a configuration in which the DCDC converter 32 is turned on and off multiple times, it is possible to suppress the diagnoses of the positive-side relay 36 and the negative-side relay 38 from becoming complicated.

[0097] [Second embodiment] Hereinafter, a relay diagnostic device 40 according to a second embodiment will be described. It should be noted that the same reference numerals are given to the same or similar components as those of the first embodiment, and duplicate descriptions thereof will be omitted. Figures 1 to 5 The configuration and voltage shown are described without reference to individual figure numbers.

[0098] like Figure 6 , Figure 7 and Figure 8 As shown in the flowchart of , the relay diagnosis device 40 of the second embodiment is different in that step S2 and step S4 are added before step S10. Steps after step S10 are the same as those of the first embodiment, and thus description thereof is omitted.

[0099] In the relay diagnostic device 40 of the second embodiment, before the output of the ON signal to the DCDC converter 32 and when the OFF signal is output to the positive-side relay 36, the step of detecting the voltage VC by the third voltage sensor 46 can be executed. In addition, in the relay diagnostic device 40, the program is configured to diagnose whether the positive-side relay 36 has a malfunction (stuck-closed abnormality) by shifting to the next step according to the value of the detected voltage VC before the output of the ON signal to the DCDC converter 32. For example, when the voltage VC detected by the third voltage sensor 46 is 0 (V), it is diagnosed that the positive-side relay 36 is in a state of stuck-closed abnormality.

[0100] [Function of the Second Embodiment] like Figure 8 As shown, in step S2, the control system 50 detects the voltage VC with the third voltage sensor 46 before outputting the on signal to the DCDC converter 32 and when outputting the off signal to the positive-side relay 36. Then, the control system 50 shifts to step S4.

[0101] In step S4 , control system 50 determines whether voltage VC is not 0 (V). If voltage VC is not 0 (V) ( S4 : Yes), the process proceeds to step S10 . If voltage VC is 0 (V) ( S4 : No), the process proceeds to step S34 .

[0102] In the stage before the state of the DCDC converter 32 is changed to the open state, the positive side relay 36 is in the open state, which is a normal state. Here, when the voltage VC is 0 (V), since the state of the positive side relay 36 is in the closed state, the control system 50 diagnoses that there is a closed stuck abnormality for the positive side relay 36. In this way, in the second embodiment, it is possible to diagnose that the positive side relay 36 has a malfunction in the early stage of a stroke. It should be noted that the functions of each step after step S10 are the same as those of the first embodiment, so the description is omitted.

[0103] [Variation] The embodiments of the present invention are not limited to the first and second embodiments, and it goes without saying that various modifications can be made without departing from the gist of the invention.

[0104] like Fig. 9 As shown, as a modified example, a hybrid vehicle 10 equipped with a relay diagnostic device 90 may be used. In addition, the same or similar components as those of the first embodiment and the second embodiment are denoted by the same reference numerals, and the description thereof will be omitted.

[0105] The relay diagnostic device 90 is an example of a relay diagnostic device for a vehicle. The relay diagnostic device 90 diagnoses whether there is malfunction (closing stuck abnormality and opening stuck abnormality) in one stroke for the positive side relay 36 and the negative side relay 38. As an example, the relay diagnostic device 90 includes a first voltage sensor 42, a second voltage sensor 44, a third voltage sensor 46, and a control system 50.

[0106] The difference is that, in the relay diagnostic device 40 of the first embodiment, the relay diagnostic device 90 swaps the configuration of the positive side with the configuration of the negative side. That is, the positive side relay 36 is an example of the second relay, and the negative side relay 38 is an example of the first relay. The first voltage sensor 42 is the same as the first embodiment. The third voltage sensor 46 detects the voltage VC which is the voltage between the terminals of the negative side relay 38.

[0107] Specifically, the second voltage sensor 44 is connected to the wiring 33B between the positive-side relay 36 and the main battery 26, and is connected to the wiring 35A between the negative-side relay 38 and the DCDC converter 32. The second voltage sensor 44 detects a voltage VB which is a potential difference between the first electric wire 33 between the positive-side relay 36 and the main battery 26 and the second electric wire 35 between the negative-side relay 38 and the DCDC converter 32.

[0108] exist Fig.10 Curves GA, GB, GC, GD, GE, GF, and GG for the relay diagnostic device 90 are shown. Curve GA indicates the timing of sending a closing signal and an opening signal to the negative-side relay 38. Curve GB indicates the timing of sending a closing signal and an opening signal to the positive-side relay 36. Curve GC indicates the voltage VA. Curve GD indicates the state in which the voltage VA is reduced when the DCDC converter 32 is turned off. Curve GE indicates the state in which the voltage VA is maintained when the positive-side relay 36 is turned off. Curve GF indicates the voltage VB. Curve GG indicates the voltage VC.

[0109] It should be noted that the curves GA, GB, GC, GD, GE, GF, and GG show the same tendency as the curves G1, G2, G3, G4, G5, G6, and G7 of the relay diagnostic device 40, and thus description thereof is omitted. In this way, in the relay diagnostic device 90 of the modified example, it is also possible to diagnose whether there is malfunction (closing stuck abnormality and opening stuck abnormality) for the positive side relay 36 and the negative side relay 38 within one stroke.

[0110] The vehicle is not limited to the hybrid vehicle 10 , but may be an electric vehicle (EV).

[0111] When the voltage VC=0 (V) is diagnosed, even if the detected voltage is not 0 (V), it can be regarded as 0 (V) as long as it is a value within the range of measurement error with respect to 0 (V).

Claims

1. A relay diagnostic device for a vehicle, It is characterized in that In a vehicle in which a first electric wire and a second electric wire connect a power storage unit and a converter, the operation of a first relay and the operation of a second relay are diagnosed, the first electric wire is provided with the first relay, and the second electric wire has a different polarity from the first electric wire and is provided with the second relay, the vehicle relay diagnostic device having: a first detection unit configured to detect a voltage of the converter; a second detection unit that detects a voltage as a potential difference between the first electric wire between the first relay and the converter and the second electric wire between the second relay and the power storage unit; a third detection unit configured to detect a voltage between terminals of the first relay; as well as a control system having a processor and a memory, and controlling the converter, the first relay and the second relay, The processing performed by the control system includes: a step of matching a voltage of the converter with a voltage of the power storage unit; When the converter is in an on state, outputting a closing signal to the first relay; The step of diagnosing that the first relay is in an opening stuck abnormality when both the voltage detected by the second detection unit and the voltage between the terminals detected by the third detection unit cannot be detected; The step of outputting a closing signal to the second relay when the converter is turned on and the first relay is closed; When a shutdown signal is output to the converter and the voltage of the first detection unit decreases, diagnosing that the second relay is in an abnormal state of being stuck in opening; After the converter is in an off state and the first relay is in a closed state, if the voltage of the first detection unit does not decrease after an opening signal is output to the second relay, diagnosing that the second relay is stuck closed abnormally; and The step of diagnosing that the first relay is stuck closed abnormally when the voltage between the terminals of the third detection unit is 0 V after an opening signal is output to the first relay while the converter is in an off state and the second relay is in an open state.

2. The vehicle relay diagnostic device according to claim 1, It is characterized in that The processing performed by the control system includes: Before outputting an on signal to the converter and when outputting an off signal to the first relay, detecting a voltage between the terminals by the third detector; and A step of diagnosing that the first relay is stuck closed abnormally when the voltage between the terminals detected by the third detection unit is 0 V.

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