Control device of vehicle

Abstract

To provide a control device of a vehicle which can suppress erroneous determination of welding of a system main relay.SOLUTION: A control device of a vehicle is provided on a vehicle which includes an engine, a high voltage system composed of a rotary electric machine, an inverter, a high voltage battery, a high voltage power line, a capacitor and a system main relay, and a low voltage system composed of an auxiliary machine, a low voltage battery, a DC / DC converter and a low pressure power line, determines welding of the system main relay, on the basis of the voltage of the capacitor after cut-off of the system main relay and discharge, and does not determine welding of the system main relay, when the voltage of the low voltage system or the low voltage battery is higher than a normal time.SELECTED DRAWING: Figure 2

Description

[Technical field]

[0001] The present invention relates to a vehicle control device. [Background technology]

[0002] Patent Document 1 discloses a technique for determining whether a system main relay is welded by using the voltage of a capacitor after discharging. [Prior art documents] [Patent documents]

[0003] [Patent Document 1] JP 2007-250335 A Summary of the Invention [Problem to be solved by the invention]

[0004] In a vehicle equipped with a high-voltage system having an engine, a rotating electric machine capable of cranking the engine via a transmission mechanism, an inverter for driving the rotating electric machine, a high-voltage battery for supplying power to the rotating electric machine, a capacitor attached to a high-voltage power line electrically connecting the high-voltage battery and the inverter, and a system main relay provided on the high-voltage power line closer to the high-voltage battery than the capacitor, and a low-voltage system having a low-voltage battery for supplying power to auxiliary equipment, a DC / DC converter electrically connected to the high-voltage power line, and a low-voltage power line electrically connecting the low-voltage battery and the DC / DC converter, if a welding determination for the system main relay is performed using the voltage of the capacitor during rescue in which a 24V rescue battery is electrically connected to the low-voltage battery, there is a risk that the capacitor will not be sufficiently discharged as the voltage on the low-voltage side increases, resulting in an erroneous determination being made as to whether the system main relay is welded.

[0005] The present invention has been made in consideration of the above-mentioned problems, and an object of the present invention is to provide a vehicle control device that can suppress erroneous determination of welding of a system main relay. [Means for solving the problem]

[0006] In order to solve the above-mentioned problems and achieve the object, a vehicle control device according to the present invention is provided for a vehicle including a high-voltage system including an engine, a rotating electric machine capable of cranking the engine via a transmission mechanism, an inverter for driving the rotating electric machine, a high-voltage battery for supplying power to the rotating electric machine, a capacitor attached to a high-voltage power line electrically connecting the high-voltage battery and the inverter, and a system main relay provided on the high-voltage power line closer to the high-voltage battery than the capacitor, and a low-voltage system including a low-voltage battery for supplying power to auxiliary equipment, a DC / DC converter electrically connected to the high-voltage power line, and a low-voltage power line electrically connecting the low-voltage battery and the DC / DC converter, and the vehicle control device judges whether the system main relay has welded based on the voltage of the capacitor after the system main relay is disconnected and discharged, and is characterized in that the judgment of welded is not performed when the voltage of the low-voltage system or the low-voltage battery is higher than normal. Effect of the Invention

[0007] The vehicle control device according to the present invention has an effect of suppressing erroneous determination of welding of the system main relay. [Brief description of the drawings]

[0008] [Figure 1] FIG. 1 is a schematic configuration diagram of a vehicle according to an embodiment. [Diagram 2] FIG. 2 is a flowchart showing an example of control performed by the MGECU according to the embodiment. [Diagram 3]FIG. 3 is a diagram showing an example of a discharge sequence. DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS

[0009] DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS An embodiment of a vehicle control device according to the present invention will be described below. However, the present invention is not limited to the embodiment.

[0010] 1 is a schematic diagram of a vehicle 1 according to an embodiment. The vehicle 1 according to the embodiment is a hybrid vehicle including an engine 10, a power transmission (T / M) 20 that transmits power from the engine 10 to drive wheels DW, and a motor generator MG. The vehicle 1 further includes an inverter 30 that drives the motor generator MG, a high-voltage battery 40 connected to the motor generator MG via the inverter 30, a low-voltage battery 50 that stores power supplied to an auxiliary device 100, etc., a DC / DC converter 60 connected to the inverter 30, the high-voltage battery 40, and the low-voltage battery 50, an engine ECU 70 that controls the engine 10, a gear shift ECU 80 that controls the power transmission 20, and an MGECU 90 that controls the inverter 30 (motor generator MG) and the DC / DC converter 60.

[0011] The engine 10 includes a crankshaft 11 connected to a plurality of cylinders and pistons arranged in each cylinder, a throttle valve, a fuel injection valve, a spark plug, a crank angle sensor, etc. The engine 10 further includes a starter 15 that outputs cranking torque to the crankshaft 11 to start the engine 10. The starter 15 includes a pinion gear that can mesh with a ring gear that rotates integrally with the crankshaft 11, a DC motor that rotates the pinion gear, an actuator that moves the pinion gear back and forth between a meshing position with the ring gear and a retracted position, etc., and is controlled by the engine ECU 70.

[0012] The power transmission device 20 includes a starting device connected to the crankshaft 11 of the engine 10, a speed change mechanism (automatic transmission) connected to the starting device, a hydraulic control device controlled by a speed change ECU 80 to supply hydraulic pressure to the starting device and the speed change mechanism, and the like (all not shown). The starting device includes a front cover connected to the crankshaft 11, a torque converter (fluid transmission device) having a pump impeller, a turbine runner, a stator, and the like, a damper mechanism that damps vibrations from the engine 10, and a clutch (lock-up clutch) that can connect the front cover and the speed change mechanism via the damper mechanism, and the like. The speed change mechanism is, for example, a 4- to 10-speed automatic speed change mechanism, and includes an input shaft, an output shaft, at least one planetary gear mechanism, and a plurality of clutches and brakes (hydraulic engagement elements), and the like. The speed change mechanism changes the speed of the power transmitted from the starting device (damper mechanism) to the input shaft in a plurality of stages and outputs it to the output shaft. The power output to the output shaft of the transmission mechanism is transmitted to the drive wheels DW via a differential gear DF ​​and a drive shaft DS. The transmission mechanism may be, for example, a belt-type continuously variable transmission (CVT) or a dual clutch transmission.

[0013] The motor generator MG is a synchronous generator motor (three-phase AC motor) including a stator and a rotor. The rotor of the motor generator MG is inseparably connected to an end of the crankshaft 11 of the engine 10 opposite to the power transmission device 20 side via a transmission mechanism 17. In this embodiment, the transmission mechanism 17 is a winding transmission mechanism including a pulley fixed to the crankshaft 11, a pulley fixed to the rotor of the motor generator MG, and a belt wound around both pulleys. The transmission mechanism 17 may be a gear mechanism or a chain mechanism. The motor generator MG may be a DC motor, and may be disposed (directly connected) between the engine 10 and the power transmission device 20.

[0014] The inverter 30 includes, for example, six transistors and six diodes connected in parallel in the opposite directions to each transistor, and is controlled by the MGECU 90. The high-voltage battery 40 is, for example, a lithium-ion secondary battery or a nickel-hydrogen secondary battery having a rated output voltage of 48 V. The low-voltage battery 50 is, for example, a secondary battery such as a lead-acid battery having a rated output voltage of 12 V.

[0015] A high-voltage power line LH is connected to the high-voltage battery 40 via a system main relay SMR. The inverter 30 is connected to the high-voltage power line LH. The system main relay SMR is, for example, a semiconductor relay that is controlled to open and close by the MGECU 90. A capacitor is provided between the system main relay SMR of the high-voltage power line LH and the inverter 30 to smooth the DC voltage supplied from the high-voltage battery 40 and supply the smoothed DC voltage to the inverter 30.

[0016] The DC / DC converter 60 is electrically connected to the high-voltage power line LH (system main relay SMR), and is also electrically connected to the low-voltage battery 50 and the auxiliary equipment 100 via a low-voltage power line LL. The DC / DC converter 60 also includes a first switching element and a second switching element, each of which has a transistor and a diode, a reactor, and a control circuit that controls the switching of the first switching element and the second switching element based on a voltage command value from the MGECU 90.

[0017] The engine ECU 70 exchanges information with the transmission ECU 80 and the MGECU 90 via shared and dedicated communication lines. The engine ECU 70 also acquires signals from a start switch for instructing system startup of the vehicle 1, a shift position sensor, an accelerator pedal position sensor, a vehicle speed sensor, a throttle opening sensor, an air flow meter, a cam position sensor, a crank angle sensor, etc. The engine ECU 70 controls the engine 10, the starter 15, related accessories 100, etc. based on signals from these sensors, the transmission ECU 80, the MGECU 90, etc.

[0018] The MGECU 90 exchanges information with the engine ECU 70 and the shift ECU 80 via shared and dedicated communication lines. The MGECU 90 also acquires signals from a rotational position sensor and various voltage sensors, etc. The MGECU 90 is connected to a drive circuit of the inverter 30 and a control IC of the DC / DC converter 60 via dedicated communication lines, etc., and controls the inverter 30 and the DC / DC converter 60 based on command signals from the engine ECU 70 and signals from various sensors, etc. The functions of the engine ECU 70, the shift ECU 80, and the MGECU 90 may be integrated into a single electronic control device, or the functions of the engine ECU 70 and the shift ECU 80, or the functions of the engine ECU 70 and the MGECU 90 may be integrated into a single electronic control device.

[0019] In the vehicle 1 configured as described above, the engine 10 is not started when the driver turns on the start switch, and the engine ECU 70 transmits a command signal to the MGECU 90 to start the engine 10 with cranking torque from the motor generator MG in response to a start request from the driver. Upon receiving the command signal from the engine ECU 70, the MGECU 90 closes (turns on) the system main relay SMR, and then controls the switching of the inverter 30 so that the motor generator MG outputs cranking torque to the crankshaft 11. As a result, the cranking torque is output from the motor generator MG to the crankshaft 11 via the transmission mechanism 17, and the engine 10 is cranked and started.

[0020] Furthermore, the engine ECU 70 executes intake air amount control, fuel injection control, ignition control, and the like of the engine 10 based on signals from various sensors, etc., so that the engine 10 outputs power according to the torque required by the driver and the electric power generated or consumed by the motor generator MG according to the state of the vehicle 1 when the vehicle 1 is traveling. At this time, the MGECU 90 performs switching control of the inverter 30 and the DC / DC converter 60 so that the motor generator MG generates or consumes the required electric power. In this embodiment, while the vehicle 1 is traveling, the motor generator MG mainly operates as a generator that generates electric power using a part of the power from the engine 10 operated under load, and is appropriately driven by the electric power from the high-voltage battery 40 to output a driving torque (assist torque) to the crankshaft 11 of the engine 10. Furthermore, when braking the vehicle 1, the motor generator MG outputs a regenerative braking torque to the crankshaft 11 of the engine 10.

[0021] Furthermore, when a predetermined starter starting condition is satisfied immediately after the start switch is turned on, the engine ECU 70 controls the starter 15 to output a cranking torque to the crankshaft 11 while keeping the system main relay SMR open, thereby starting the engine 10. At this time, the starter 15 is driven by electric power from the low-voltage battery 50. In this embodiment, the starter starting condition is satisfied when the high-voltage battery temperature (or the outside air temperature) at the timing of starting the engine 10 is lower than a predetermined temperature, when the battery voltage of the high-voltage battery 40 at the timing of starting the engine 10 is lower than a predetermined voltage, when various operation checks executed immediately after the start switch is turned on are not completed even after a predetermined time has elapsed, when a predetermined timing for forcibly using the starter 15 to prevent deterioration of the starter 15 arrives, etc.

[0022] In the vehicle 1 according to the embodiment, a high-voltage system is configured by the motor generator MG, the inverter 30, the high-voltage battery 40, the high-voltage power line LH, the capacitor, the system main relay SMR, etc. In the vehicle 1 according to the embodiment, a low-voltage system is configured by the auxiliary device 100, the low-voltage battery 50, the DC / DC converter 60, the low-voltage power line LL, etc.

[0023] In the vehicle 1 according to the embodiment, the MGECU90 shuts off the system main relay SMR by turning off the ignition, and performs a discharge to remove the charge from the capacitor. At this time, the MGECU90 judges whether the system main relay SMR is welded based on the voltage of the capacitor after the discharge. The MGECU90 judges whether the system main relay SMR is welded if the discharge function is normal and the voltage of the capacitor is lower than a predetermined first voltage (first predetermined voltage) in the welding judgment of the system main relay SMR, and judges whether the system main relay SMR is abnormal if the voltage does not drop below the first voltage. Furthermore, the MGECU90 does not judge whether the system main relay SMR is welded when the discharge function is not normal. Furthermore, the MGECU90 does not judge whether the system main relay SMR is welded when the voltage of the low voltage side (low voltage system or low voltage battery) is higher than normal.

[0024] In the vehicle 1 according to the embodiment, for example, when the high-voltage battery 40 and the low-voltage battery 50 are insufficient in charge capacity (dead battery), the rescue battery of the rescue vehicle and the low-voltage battery 50 of the vehicle 1 are electrically connected by a booster cable, and the engine 10 can be started by the starter 15 by supplying power from the rescue battery of the rescue vehicle. Here, if the rescue battery is a 24 [V] battery, the voltage on the low-voltage side rises to about 24 [V] during rescue. Therefore, even if the capacitor is discharged during rescue, the voltage of the capacitor only drops to about 24 [V] on the low-voltage side, and discharge cannot be performed sufficiently, and there is a risk of erroneous determination of welding of the system main relay SMR based on the voltage of the capacitor on the assumption that the low-voltage side is 12 [V]. Therefore, in this embodiment, when the voltage on the low voltage side increases from the normal state (12 [V]) and reaches or exceeds a predetermined second voltage (second predetermined voltage), the MGECU 90 does not perform a welding determination for the system main relay SMR.

[0025] In the vehicle 1 according to the first embodiment, various voltages such as the voltage of the capacitor are detected by voltage sensors provided corresponding to the respective voltages, and the various voltages detected by the respective voltage sensors are output to, for example, the MGECU 90.

[0026] Fig. 2 is a flowchart showing an example of control performed by the MGECU 90 according to the embodiment. Fig. 3 is a diagram showing an example of a discharge sequence.

[0027] First, the MGECU 90 turns off the system main relay SMR to discharge the capacitor (step S1). Next, the MGECU 90 determines whether the discharge function is normal or not (step S2). If the MGECU 90 determines that the discharge function is not normal (No in step S2), it does not perform a welding determination of the system main relay SMR (step S5) and ends the series of controls.

[0028] In step S2, if the MGECU 90 determines that the discharge function is normal (Yes in step S2), it determines whether the high voltage side (the voltage of the capacitor) is equal to or higher than the first voltage (step S3). If the MGECU 90 determines that the high voltage side (the voltage of the capacitor) is not equal to or higher than the first voltage (No in step S3), it performs a welding determination of the system main relay SMR (step S6) and ends the series of controls.

[0029] In step S3, if the MGECU90 determines that the high-voltage side (the voltage of the capacitor) is equal to or higher than the first voltage (Yes in step S3), it determines whether or not the low-voltage side (the voltage of the low-voltage system or the low-voltage battery) is equal to or higher than the second voltage (step S4). If the MGECU90 determines that the low-voltage side (the voltage of the low-voltage system or the low-voltage battery) is equal to or higher than the second voltage (Yes in step S4), it does not perform a welding determination of the system main relay SMR (step S5) and ends the series of controls. On the other hand, if the MGECU90 determines that the low-voltage side (the voltage of the low-voltage system or the low-voltage battery) is not equal to or higher than the second voltage (No in step S4), it performs a welding determination of the system main relay SMR (step S6) and ends the series of controls.

[0030] In this embodiment, when a 24V rescue battery is electrically connected to a low-voltage battery 50 that has insufficient charging capacity (dead battery) to provide rescue, that is, when the voltage on the low-voltage side (the voltage of the low-voltage system or low-voltage battery) is higher than normal, a welding determination of the system main relay SMR based on the voltage of the capacitor is not performed, thereby suppressing erroneous determination of a welding of the system main relay SMR. [Explanation of symbols]

[0031] 10 Engine 40 High Voltage Battery 50 Low Voltage Battery 60 DC / DC Converter 90 MGECU MG Motor Generator SMR System Main Relay

Claims

[Claim 1] The engine, a high-voltage system including a rotating electric machine capable of cranking the engine via a transmission mechanism, an inverter for driving the rotating electric machine, a high-voltage battery for supplying power to the rotating electric machine, a capacitor attached to a high-voltage power line electrically connecting the high-voltage battery and the inverter, and a system main relay provided on the high-voltage power line closer to the high-voltage battery than the capacitor; a low voltage system including a low voltage battery for supplying power to an auxiliary device, a DC / DC converter electrically connected to the high voltage power line, and a low voltage power line electrically connecting the low voltage battery and the DC / DC converter; The vehicle is provided with determining whether the system main relay is welded based on a voltage of the capacitor after the system main relay is disconnected and discharged; A control device for a vehicle, A vehicle control device, comprising: a control unit for a vehicle that does not perform the determination of welding when the voltage of the low voltage system or the low voltage battery is higher than normal.

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