Vehicle control device

Abstract

To properly protect a relay when the relay is required to be closed after starting an internal combustion engine in a vehicle that comprises the internal combustion engine, an electric motor inseparatably connected to an output shaft of the internal combustion engine, and a power storage device connected to the electric motor through the relay.SOLUTION: A control device of a vehicle comprises: an internal combustion engine; an electric motor inseparatably connected to an output shaft of the internal combustion engine; and a power storage device connected to the electric motor through a relay, and is configured to permit the relay to be closed when the electric motor is rotated with the output shaft of the internal combustion engine during operation and a voltage of the power storage device is a predetermined value or more and prohibit the relay from being closed when the electric motor is rotated with the output shaft of the internal combustion engine during operation and the voltage of the power storage device is less than the predetermined value.SELECTED DRAWING: Figure 3

Description

[Technical Field]

[0001] The present disclosure relates to a control device for a vehicle including an internal combustion engine, an electric motor inseparably connected to an output shaft of the internal combustion engine, and an electric storage device connected to the electric motor via a relay. [Background technology]

[0002] Conventionally, a hybrid vehicle has been known that includes an engine (internal combustion engine), a clutch disposed in a power transmission path between the engine and drive wheels, a motor / generator (electric motor) disposed in the power transmission path between the clutch and drive wheels, an automatic transmission disposed in the power transmission path between the motor / generator and drive wheels, a battery, a power control unit disposed between the battery and the motor / generator, and a system relay disposed between the battery and the power control unit (see, for example, Patent Document 1). When a driver performs a power-off operation, the control device of this hybrid vehicle disconnects the system relay when the motor / generator's rotation speed is equal to or lower than a specified rotation speed. This prevents welding of the system relay, which may occur when the system relay is disconnected while the back electromotive force generated by the motor / generator is large. Furthermore, the control device stops operation of the engine when the power-off operation is performed while the engine is running, and engages the clutch if the motor / generator is rotating at the time of the power-off operation. As a result, the motor / generator is connected to the stopped engine via the clutch, and the load applied to the motor / generator increases by the inertia of the engine, causing the motor / generator's rotation speed to decrease quickly. As a result, the counter electromotive force generated by the motor generator is reduced early, and the time from when the power is turned off until the system relay is disconnected is prevented from becoming long. [Prior art documents] [Patent documents]

[0003] [Patent Document 1] Japanese Patent Application Publication No. 2020-093727 Summary of the Invention [Problem to be solved by the invention]

[0004] In a vehicle having a configuration in which the clutch between the engine and the motor generator is omitted from the conventional hybrid vehicle, the engine may be started in a state in which the relay is open and the electrical connection between the motor generator and the battery is released. In such a case, after the engine starts, the motor generator rotates (idles) along with the running engine, generating a back electromotive force. Therefore, if the relay between the motor generator and the battery is closed while the motor generator is rotating along with the running engine, an excessive current (back electromotive force) due to the back electromotive force may be applied, causing the relay to malfunction.

[0005] Therefore, the main object of the present disclosure is to effectively protect a relay when a request to close the relay is made after the internal combustion engine is started in a vehicle that includes an internal combustion engine, an electric motor that is inseparably connected to the output shaft of the internal combustion engine, and an electric storage device that is connected to the electric motor via a relay. [Means for solving the problem]

[0006] The vehicle control device disclosed herein is a vehicle control device that includes an internal combustion engine, an electric motor that is inseparably connected to the output shaft of the internal combustion engine, and an electric storage device that is connected to the electric motor via a relay, and when the electric motor is rotating along with the output shaft of the internal combustion engine while it is in operation and the voltage of the electric storage device is equal to or greater than a predetermined value, the control device allows the relay to be closed, and when the electric motor is rotating along with the output shaft of the internal combustion engine while it is in operation and the voltage of the electric storage device is less than the predetermined value, the control device prohibits the relay from being closed. [Brief explanation of the drawings]

[0007] [Figure 1]1 is a schematic configuration diagram of a vehicle controlled by a control device of the present disclosure. [Figure 2] FIG. 2 is a system diagram showing an electric power system of the vehicle of FIG. [Figure 3] 4 is a flowchart showing a relay closure permission / denial routine executed by the vehicle control device of the present disclosure. [Figure 4] 10 is a flowchart showing another relay closing permission / denial routine executed by the vehicle control device of the present disclosure. DETAILED DESCRIPTION OF THE INVENTION

[0008] Next, embodiments of the present disclosure will be described with reference to the drawings.

[0009] 1 is a schematic diagram showing a vehicle 1 controlled by a control device of the present disclosure. The vehicle 1 shown in the figure is a hybrid vehicle including an engine 10, a power transmission device 20 that transmits power from the engine 10 to drive wheels DW, and a motor generator MG. The vehicle 1 also includes an inverter 30 that drives the motor generator MG, a high-voltage battery 40 as a power storage device connected to the motor generator MG via the inverter 30, a low-voltage battery 50 as another power storage device that stores power to be supplied to various accessories, a DC / DC converter 60 as a voltage conversion device connected to the inverter 30, the high-voltage battery 40, and the low-voltage battery 50, an engine electronic control unit (hereinafter referred to as the "engine ECU") 70 that controls the engine 10, a transmission electronic control unit (hereinafter referred to as the "transmission ECU") 80 that controls the power transmission device 20, and a motor electronic control unit (hereinafter referred to as the "MGECU") 90 that controls the inverter 30 (motor generator MG) and the DC / DC converter 60.

[0010] The engine 10 is an internal combustion engine that generates power through the explosive combustion of a mixture of air and hydrocarbon fuel such as gasoline, diesel, or LPG, and includes a plurality of cylinders (combustion chambers) (not shown), a crankshaft (output shaft) 11 connected to pistons (not shown) arranged in each cylinder, an electronically controlled throttle valve (not shown), a plurality of fuel injection valves and spark plugs, a crank angle sensor that detects the rotational position (crank angle) of the crankshaft 11, etc. The engine 10 also 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 position where it meshes with the ring gear and a retracted position, etc., and is controlled by the engine ECU 70.

[0011] 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 transmission ECU 80 to supply hydraulic pressure to the starting device and the speed change mechanism, and other components (all not shown). The starting device includes a front cover connected to the crankshaft 11, a torque converter (hydraulic power transmission) having a pump impeller, a turbine runner, a stator, and other components, 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. 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 multiple clutches and brakes (hydraulic engagement elements), respectively. The speed change mechanism changes the speed of power transmitted from the starting device (damper mechanism) to the input shaft in multiple stages and outputs the power 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.

[0012] The motor generator MG is a synchronous generator motor (three-phase AC motor) including a stator and rotor R (not shown). The rotor R of the motor generator MG is inseparably connected to an end of the crankshaft 11 of the engine 10 opposite 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 R 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 also be a DC motor and may be disposed (directly connected) between the engine 10 and the power transmission device 20.

[0013] The inverter 30 includes, for example, six transistors and six diodes connected in parallel to each transistor in the reverse direction, and is controlled by the MGECU 90. The high-voltage battery 40 is, for example, a lithium-ion secondary battery or a nickel-metal hydride secondary battery having a rated output voltage of 40-50 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. As shown in FIG. 2 , a high-voltage power line LH is connected to the high-voltage battery 40 via a system main relay SMR, and the inverter 30 is connected to the high-voltage power line LH. In this embodiment, the system main relay SMR is, for example, a semiconductor relay whose opening and closing is controlled by the MGECU 90. This enables the system main relay SMR to be miniaturized and have a longer life. In addition, a voltage detection circuit 45 is connected to the power line connecting the high-voltage battery 40 and the system main relay SMR. The voltage detection circuit 45 detects the battery voltage Vb (actual voltage) which is the output voltage of the high-voltage battery 40 (the voltage of the high-voltage power line LH), and outputs (transmits) it to the MGECU 90.

[0014] As shown in FIG. 2 , the DC / DC converter 60 is connected to a high-voltage power line LH (system main relay SMR) and is also connected in parallel to various auxiliary devices, including a low-voltage battery 50 and the starter 15, as loads, via a low-voltage power line LL and an output relay Ro. In this embodiment, the output relay Ro is a semiconductor relay whose opening and closing is controlled by the MGECU 90. As shown in the figure, the DC / DC converter 60 includes first and second switching elements, each having a transistor and a diode, a coil (reactor), and a control IC (control circuit) that controls the switching of the first and second switching elements based on a voltage command value from the MGECU 90 (all of which are not shown). A smoothing capacitor 64 and a voltage detection circuit 65 are connected to the low-voltage power line LL (between the coil and the output relay Ro). The voltage detection circuit 65 detects the voltage on the low-voltage power line LL (the voltage across the smoothing capacitor 64), i.e., the output voltage Vo of the DC / DC converter 60, and outputs (transmits) the detected voltage to the MGECU 90.

[0015] The engine ECU 70 includes a microcomputer having a CPU, ROM, RAM, input / output devices, etc. (not shown), and exchanges information with the transmission ECU 80 and 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 for detecting the shift position of a shift lever, an accelerator pedal position sensor for detecting the amount of depression (operation amount) of an accelerator pedal, a vehicle speed sensor, a throttle opening sensor for detecting the throttle opening of a throttle valve, an air flow meter for detecting the amount of intake air, a cam position sensor of a variable valve timing mechanism (none of which are shown), the crank angle sensor, etc. The engine ECU 70 controls the engine 10 and related accessories such as the starter 15 based on signals from these sensors and from the transmission ECU 80, MGECU 90, etc.

[0016] The MGECU 90 includes a microcomputer having a CPU, ROM, RAM, input / output devices, etc. (not shown), and exchanges information with the engine ECU 70 and the transmission ECU 80 via shared and dedicated communication lines. The MGECU 90 also acquires signals from a rotational position sensor (not shown) that detects the rotational position of the rotor R of the motor-generator MG, a current sensor that detects the phase current applied to the motor-generator MG, a voltage detection circuit 45 that detects the battery voltage Vb, and a voltage detection circuit 65 that detects the output voltage Vo of the low-voltage power line LL. The MGECU 90 is connected to the drive circuit of the inverter 30 and the 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. The functions of the engine ECU 70, the transmission 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 transmission ECU 80, or the functions of the engine ECU 70 and the MGECU 90, may be integrated into a single electronic control device. In addition, an integrated ECU that controls the inverter 30 (motor generator MG) and DC / DC converter 60, manages the high-voltage battery 40, and controls the opening and closing of the system main relay SMR may be integrated with the DC / DC converter 60, for example.

[0017] In vehicle 1 configured as described above, engine 10 is not started when the driver turns on the start switch, and engine ECU 70 sends a command signal to MGECU 90 to start engine 10 with cranking torque from motor generator MG in response to a driver's request to start the vehicle (for example, releasing the brake pedal, not shown). Upon receiving the command signal from engine ECU 70, MGECU 90 closes (turns on) system main relay SMR and then controls the switching of inverter 30 so that motor generator MG outputs cranking torque to crankshaft 11. As a result, cranking torque is output from motor generator MG to crankshaft 11 via transmission mechanism 17, and engine 10 is cranked and started.

[0018] Furthermore, the engine ECU 70 controls the intake air amount, fuel injection, ignition, and the like of the engine 10 based on signals from various sensors, etc., so that the engine 10 outputs power corresponding to the torque requested by the driver and the electric power generated or consumed by the motor generator MG depending on the state of the vehicle 1 during vehicle running. At this time, the MGECU 90 controls the switching 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 running, the motor generator MG mainly operates as a generator that generates electric power using a portion of the power from the engine 10, which is operated under load, and is appropriately driven by electric power from the high-voltage battery 40 to output a driving torque (assist torque) to the crankshaft 11 of the engine 10. Furthermore, during braking of the vehicle 1, the motor generator MG outputs a regenerative braking torque to the crankshaft 11 of the engine 10.

[0019] Furthermore, if a predetermined starter start condition is satisfied immediately after the start switch is turned on, the engine ECU 70 controls the starter 15 to output 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 power from the low-voltage battery 50. In this embodiment, the starter start condition is satisfied when the battery temperature (or the outside air temperature) at the timing to start the engine 10 is lower than a predetermined temperature, when the battery voltage Vb at the timing to start 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 within a predetermined time, when a predetermined timing to forcibly use the starter 15 to prevent deterioration of the starter 15 arrives, etc.

[0020] When engine 10 is started by starter 15 in this way, motor generator MG (rotor R) rotates (idles) along with crankshaft 11 of engine 10 during operation, i.e., after engine start, without receiving power supply from high-voltage battery 40, and in motor generator MG, back electromotive force (back electromotive voltage) is generated as rotor R rotates. For this reason, when system main relay SMR is closed to operate motor generator MG etc. after engine 10 has started, an excessive current (back electromotive current) based on the back electromotive force generated in motor generator MG is applied, which may cause relay failure (on failure or off failure).

[0021] Based on this, in vehicle 1, when the start switch is turned on, a relay closure permission / prohibition routine shown in FIG. 3 is repeatedly executed at predetermined time intervals (very short time intervals) by the MGECU 90 as a control device to determine whether or not to close the system main relay SMR. When starting the routine of FIG. 3, the MGECU 90 acquires information necessary for determining whether or not to close the system main relay SMR, such as the rotation speed Nm of the motor-generator MG, the battery voltage Vb of the high-voltage battery 40, and the value of flag Fsmr (step S100). The rotation speed Nm is calculated separately by the MGECU 90 based on the rotational position of the rotor R of the motor-generator MG detected by a rotational position sensor (resolver) not shown. The battery voltage Vb is detected by the voltage detection circuit 45. The flag Fsmr is set to "0" when the system main relay SMR is open (off), such as immediately after the start switch is turned on, and is set to "1" when the system main relay SMR is closed (on).

[0022] After the processing of step S100, the MGECU 90 determines whether the system main relay SMR is open based on the value of the flag Fsmr (step S110). If it is determined that the system main relay SMR is open (step S110: YES), the MGECU 90 determines whether the rotation speed Nm of the motor generator MG exceeds a predetermined threshold value Nref (step S120). The threshold value Nref used in step S120 is used to determine whether the motor generator MG (rotor R) is rotating, and is set to zero or a positive value close to zero that is less than the idle rotation speed.

[0023] When the system main relay SMR is open and the rotation speed Nm of the motor-generator MG exceeds the threshold value Nref, the engine 10 is started by the starter 15, and the motor-generator MG rotates together with the operating engine 10 (crankshaft 11). In this case, depending on the relationship between the battery voltage Vb and the back electromotive force generated in the motor-generator MG, a back electromotive force current from the motor-generator MG may flow to the high-voltage battery 40 via the inverter 30. Therefore, when it is determined that the rotation speed Nm exceeds the threshold value Nref (step S120: YES), the MGECU 90 determines whether the battery voltage Vb is less than a predetermined relay closing permission voltage Vref (step S130). The relay closing permission voltage Vref used as the threshold value in step S130 is a constant value that is adjusted in advance based on the range of the back electromotive force and back electromotive force generated when the motor-generator MG rotates together with the engine 10, the withstand current of the system main relay SMR, and the like.

[0024] If it is determined that the battery voltage Vb is less than the relay closing permission voltage Vref (step S130: YES), the MGECU 90 determines that there is a risk of a back electromotive force flowing from the motor generator MG to the high-voltage battery 40, and therefore prohibits the closing of the system main relay SMR, i.e., the operation of the motor generator MG (power conversion by the DC / DC converter 60) (step S140), and executes the processing from step S100 onwards when the next execution timing arrives. On the other hand, if it is determined that the battery voltage Vb is equal to or greater than the relay closing permission voltage Vref (step S130: NO), the MGECU 90 determines that there is no risk of a back electromotive force flowing from the motor generator MG to the high-voltage battery 40, and therefore permits the closing of the system main relay SMR (step S150), and executes the processing from step S100 onwards when the next execution timing arrives.

[0025] On the other hand, if the rotation speed Nm of the motor generator MG is equal to or less than the threshold value Nref, the engine 10 has not been started by the motor generator MG or the starter 15, and the rotation of the engine 10 and the motor generator MG has stopped. Therefore, when the MGECU 90 determines that the rotation speed Nm of the motor generator MG is equal to or less than the threshold value Nref (step S120: NO), the MGECU 90 permits the closing of the system main relay SMR, i.e., the operation of the motor generator MG (and the power conversion by the DC / DC converter 60) to allow the subsequent starting (cranking) of the engine 10 by the motor generator MG (step S150), and executes the processing from step S100 onwards in response to the arrival of the next execution timing. Then, the MGECU 90 ends the routine of FIG. 3 when it determines, based on the value of the flag Fsmr, that the system main relay SMR has been closed.

[0026] In this embodiment, once the engine 10 is started by the starter 15, stopping of the engine 10 is prohibited until the start switch is turned off after the vehicle 1 is parked, and a positive determination is made in step S120. Also, once the closing of the system main relay SMR is prohibited in step S140, the high-voltage battery 40 cannot be charged with the electric power generated by the motor generator MG, and the battery voltage Vb(SOC) cannot be increased. Therefore, once the closing of the system main relay SMR is prohibited in step S140 after the start switch is turned on, the closing of the system main relay SMR continues to be prohibited in step S140 until the start switch is turned off after the vehicle 1 is parked.

[0027] As described above, the MGECU 90, which is one of the control devices of the vehicle 1, permits the closure of the system main relay SMR (step S150) when the motor generator MG rotates together with the crankshaft 11 of the engine 10 that has been started by the starter 15 and is running (step S120: YES) and the battery voltage Vb of the high-voltage battery 40 is equal to or higher than the relay closure permission voltage Vref (predetermined value) (step S130: NO). In other words, when the battery voltage Vb of the high-voltage battery 40 is sufficiently high, even if a counter electromotive force is generated in the motor generator MG that rotates together with the crankshaft 11 of the engine 10 during operation, i.e., after start-up, the counter electromotive current does not flow from the motor generator MG to the high-voltage battery 40 side, and therefore the closure of the system main relay SMR can be permitted.

[0028] In contrast, when the motor generator MG rotates together with the crankshaft 11 of the engine 10 that has been started by the starter 15 and is running (step S120: YES) and the battery voltage Vb of the high-voltage battery 40 is lower than the relay closing permission voltage Vref (step S130: YES), the MGECU 90 prohibits closing of the system main relay SMR (step S140). As a result, even if a back electromotive force is generated in the motor generator MG that rotates together with the crankshaft 11 of the running engine 10 when the voltage of the high-voltage battery 40 is low, the system main relay SMR can be opened to prevent the back electromotive current from flowing to the system main relay SMR. As a result, in the vehicle 1 that includes the engine 10, the motor generator MG that is inseparably connected to the crankshaft 11, and the high-voltage battery 40 that is connected to the motor generator MG via the system main relay SMR, it is possible to effectively protect the system main relay SMR when closing of the system main relay SMR is requested after the engine 10 is started by the starter 15.

[0029] In vehicle 1, since motor generator MG is inseparably connected to crankshaft 11 of engine 10, in step S120 of Fig. 3, the rotation speed Ne of engine 10 may be compared with a predetermined threshold value to determine whether motor generator MG is rotating together with crankshaft 11. In addition, the SOC of high-voltage battery 40 is calculated based on battery voltage Vb, battery temperature, etc., and is correlated with battery voltage Vb. Therefore, in step S130 of Fig. 3, the SOC of high-voltage battery 40 may be compared with a predetermined threshold value to determine whether there is a risk of a back electromotive force flowing from motor generator MG to high-voltage battery 40.

[0030] Furthermore, when the engine 10 is started normally by the starter 15, the motor generator MG always rotates together with the crankshaft 11. Therefore, in the vehicle 1, the MGECU 90 may execute a relay closing permission / denial routine shown in FIG. 4. When the relay closing permission / denial routine of FIG. 4 is applied to the vehicle 1, the MGECU 90 acquires the battery voltage Vb of the high-voltage battery 40 (step S105) when it is confirmed that the engine 10 has been started normally by the starter 15, and determines whether the battery voltage Vb is less than the relay closing permission voltage Vref (step S130). When the MGECU 90 determines that the battery voltage Vb is less than the relay closing permission voltage Vref (step S130: YES), it prohibits the closing of the system main relay SMR (step S140) and ends the routine of FIG. 4. On the other hand, if it is determined that the battery voltage Vb is equal to or higher than the relay closing permission voltage Vref (step S130: NO), the MGECU 90 permits the system main relay SMR to be closed (step S150) and ends the routine of FIG.

[0031] In the above embodiment, semiconductor relays are used as the system main relay SMR and the output side relay Ro, but this is not limiting. In other words, both or either one of the system main relay SMR and the output side relay Ro may be contact relays (mechanical relays).

[0032] As described above, the vehicle control device disclosed herein permits the relay to be closed when the electric motor rotates along the output shaft of the internal combustion engine during operation and the voltage of the power storage device is equal to or higher than a predetermined value. That is, when the voltage of the power storage device is sufficiently high, even if back electromotive force is generated in the electric motor that rotates along the output shaft of the internal combustion engine during operation, i.e., after start-up, the back electromotive force does not flow from the electric motor to the power storage device, and therefore the relay can be permitted to be closed. In contrast, the control device prohibits the relay from being closed when the electric motor rotates along the output shaft of the internal combustion engine during operation and the voltage of the power storage device is less than a predetermined value. As a result, when the voltage of the power storage device is low, even if back electromotive force is generated in the electric motor that rotates along the output shaft of the internal combustion engine during operation, the relay is opened, thereby preventing a current based on the back electromotive force (back electromotive current) from flowing through the relay. As a result, in a vehicle including an internal combustion engine, an electric motor inseparably connected to the output shaft of the internal combustion engine, and an electric storage device connected to the electric motor via a relay, it is possible to effectively protect the relay when a request to close the relay is made after the internal combustion engine is started.

[0033] The control device may also determine whether the electric motor is rotating along with the output shaft of the internal combustion engine during operation based on the rotation speed of the electric motor or the rotation speed of the output shaft of the internal combustion engine, and may determine whether the voltage of the storage device is less than a predetermined value based on the actual voltage or SOC of the storage device.

[0034] Furthermore, the internal combustion engine may be driven by electric power from another power storage device different from the power storage device, and may include a starter that outputs cranking torque to the output shaft to start the internal combustion engine, and may be started by cranking using the electric motor or the starter.

[0035] In addition, the control device may allow the relay to be closed when the voltage of the storage device is equal to or greater than a predetermined value after the internal combustion engine is started by the starter, and may prohibit the relay from being closed when the voltage of the storage device is less than a predetermined value after the internal combustion engine is started by the starter.

[0036] Furthermore, the relay may be a semiconductor relay or a contact relay.

[0037] The present invention is not limited to the above-described embodiment, and various modifications can be made within the scope of the present disclosure. Furthermore, the above-described embodiment is merely a specific form of the invention described in the Summary of the Invention, and does not limit the elements of the invention described in the Summary of the Invention. [Industrial Applicability]

[0038] The invention of the present disclosure can be used in the vehicle manufacturing industry and the like. [Explanation of symbols]

[0039] 1 vehicle, 10 engine, 15 starter, 17 power transmission mechanism, 20 power transmission device, 30 inverter, 40 high-voltage battery, 45 voltage detection circuit, 70 engine electronic control unit (engine ECU), 90 motor electronic control unit (MGECU), MG motor generator, R rotor, SMR system main relay.

Claims

[Claim 1] A control device for a hybrid vehicle including an internal combustion engine, an electric motor inseparably connected to an output shaft of the internal combustion engine, and an electric storage device connected to the electric motor via a relay, A control device for a hybrid vehicle that permits the relay to be closed when the electric motor rotates along the output shaft of the internal combustion engine while the internal combustion engine is in operation and the voltage of the storage device is equal to or higher than a predetermined relay closing permission voltage, and that prohibits the relay from being closed when the electric motor rotates along the output shaft of the internal combustion engine while the internal combustion engine is in operation and the voltage of the storage device is lower than the relay closing permission voltage, the relay closing permission voltage being a constant value that is pre-adapted as the voltage of the storage device such that there is no risk of a back electromotive force, based on a back electromotive force generated when the electric motor rotates along the output shaft of the internal combustion engine, flowing into the storage device through the relay.

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