In-vehicle control device

Abstract

To more properly start an electric motor so as to deal with a failure when it occurs in a high-voltage battery.SOLUTION: An on-vehicle control device is mounted on an automobile together with an engine, an electric motor which is connected to a crank shaft of the engine and can generate power, a high-voltage battery connected to the electric motor by a high-voltage system power line, a low-voltage battery, a DC / DC converter connected to the high-voltage power line and a low-voltage system power line, and the like. In the case where a failure occurs in the high-voltage battery, the on-vehicle control device starts the electric motor based on the voltage of the high-voltage system power line, when performing battery-less control by turning off a relay and separating the high-voltage battery.SELECTED DRAWING: Figure 2

Description

[Technical Field]

[0001] The present disclosure relates to an on-board control device, and more particularly to an on-board control device including an engine, an electric motor capable of generating electricity connected to the engine crankshaft, a high-voltage battery connected to the electric motor by a high-voltage power line, a low-voltage battery, and a DC / DC converter connected to the low-voltage power line connected to the low-voltage battery and the high-voltage power line. [Background technology]

[0002] A conventional vehicle control device of this type is one that is mounted on a vehicle together with a planetary gear in which three rotating elements are connected to three shafts: an engine, a first motor, and a drive shaft; a second motor connected to the drive shaft; and a high-voltage battery that exchanges power with the first motor and the second motor (see, for example, Patent Document 1). In this device, when an abnormality occurs in the high-voltage battery, the system main relay is turned off to disconnect the high-voltage battery, and batteryless control is performed in which all of the power generated by the first motor is consumed by the second motor to drive the vehicle. [Prior art documents] [Patent documents]

[0003] [Patent Document 1] Japanese Patent Application Laid-Open No. 2013-060041 Summary of the Invention [Problem to be solved by the invention]

[0004] A vehicle equipped with an engine and an automatic transmission has been proposed that includes a generator-capable electric motor connected to the engine crankshaft and a high-voltage battery that supplies electric power to the electric motor. This vehicle often also includes a low-voltage battery that supplies electric power to auxiliary equipment, and a DC / DC converter connected to a high-voltage power line connected to the high-voltage battery and a low-voltage power line connected to the low-voltage battery. Because this vehicle has a different configuration from the vehicle described in the background art, it is not possible to perform similar batteryless control when a failure occurs in the high-voltage battery.

[0005] The vehicle control device disclosed herein has the primary purpose of more appropriately starting the electric motor in order to deal with the occurrence of a failure in the high-voltage battery in a vehicle equipped with an electric motor capable of generating electricity connected to the engine crankshaft and a high-voltage battery that exchanges power with the electric motor. [Means for solving the problem]

[0006] The in-vehicle control device of the present disclosure employs the following means to achieve the above-mentioned main object.

[0007] The in-vehicle control device of the present disclosure includes: The engine and an electric motor capable of generating electricity connected to a crankshaft of the engine; a high-voltage battery connected to the electric motor by a high-voltage power line; A low voltage battery; an auxiliary device that receives power via a low-voltage power line connected to the low-voltage battery; a DC / DC converter connected to the high-voltage power line and the low-voltage power line; a relay attached to the high-voltage power line on the high-voltage battery side of the DC / DC converter; a capacitor attached to the high-voltage power line on the DC / DC converter side of the relay; An in-vehicle control device mounted on an automobile comprising: When a failure occurs in the high-voltage battery, the relay is turned off to disconnect the high-voltage battery and, when batteryless control is performed, the electric motor is started based on the voltage of the high-voltage power line. It is characterized by:

[0008] The on-board control device disclosed herein is mounted on an automobile including an engine, an electric motor capable of generating electricity connected to the engine crankshaft, a high-voltage battery connected to the electric motor via a high-voltage power line, a low-voltage battery, an auxiliary device supplied with power via a low-voltage power line connected to the low-voltage battery, a DC / DC converter connected to the high-voltage power line and the low-voltage power line, a relay attached to the high-voltage power line closer to the high-voltage battery than the DC / DC converter, and a capacitor attached to the high-voltage power line closer to the DC / DC converter than the relay. When a fault occurs in the high-voltage battery, the on-board control device turns off the relay to disconnect the high-voltage battery. When performing batteryless control, the on-board control device starts the electric motor based on the voltage of the high-voltage power line. Batteryless control involves causing the electric motor to function as a generator, reducing the generated power using the DC / DC converter and supplying it to the low-voltage power line. Therefore, starting the electric motor is necessary when performing batteryless control. Since starting the electric motor requires sufficient power, the electric motor is started based on the voltage of the high-voltage power line, which allows the electric motor to be started more appropriately in case of a failure of the high-voltage battery.

[0009] In the on-board control device of the present disclosure, when the batteryless control is performed, the electric motor may be started using the charge stored in the capacitor when the voltage of the high-voltage power line is equal to or higher than a first threshold. In this way, the electric motor can be started quickly using the charge stored in the capacitor. Here, the first threshold can be predetermined as a voltage of the high-voltage power line that allows the electric motor to be started using the charge stored in the capacitor. As a result, the electric motor can be started more appropriately.

[0010] In the on-board control device of the present disclosure, when the batteryless control is performed, if the voltage of the high-voltage power line is less than the first threshold, the DC / DC converter may boost the power of the low-voltage power line and supply it to the high-voltage power line to start the electric motor. In this way, even if the electric motor cannot be started using the charge stored in the capacitor, the electric motor can be started using the electric power of the low-voltage system. As a result, the electric motor can be started more appropriately.

[0011] In the on-board control device disclosed herein, when the batteryless control is performed, if the voltage of the high-voltage power line is less than the first threshold and the voltage of the low-voltage power line is less than the second threshold, the voltage of the high-voltage power line is increased by the counter electromotive force of the electric motor in association with an increase in the engine speed, thereby storing charge in the capacitor, and the electric motor is started using the charge stored in the capacitor. In this way, even when the electric motor cannot be started using the charge stored in the capacitor and cannot be started using the low-voltage power, the counter electromotive force of the electric motor can be used to store charge in the capacitor and drive the motor using the charge stored in the capacitor. As a result, the electric motor can be started more appropriately. [Brief explanation of the drawings]

[0012] [Figure 1]1 is a diagram showing an outline of the configuration of an automobile 20 equipped with an in-vehicle control device according to an embodiment of the present disclosure. [Figure 2] 4 is a flowchart showing an example of batteryless control executed by a main ECU 70 according to the embodiment. DETAILED DESCRIPTION OF THE INVENTION

[0013] Next, an embodiment of the present disclosure will be described. Fig. 1 is a configuration diagram showing an outline of the configuration of an automobile 20 equipped with an on-board control device according to an embodiment of the present disclosure. As shown in the figure, the automobile 20 of the embodiment includes an engine 22, a starter 25, a motor 30, an inverter 32, an automatic transmission 40, a high-voltage battery 50, a low-voltage battery 60, a DC / DC converter 66, and a main electronic control unit (hereinafter referred to as "main ECU") 70. In the embodiment, the main electronic control unit 70 corresponds to the on-board control device.

[0014] The engine 22 is configured as a multi-cylinder (four-cylinder, six-cylinder, etc.) internal combustion engine that uses gasoline, diesel, etc., supplied as fuel from a fuel tank via a fuel supply system. The operation of the engine 22 is controlled by an engine electronic control unit (hereinafter referred to as "engine ECU") 24.

[0015] Although not shown, the engine ECU 24 is configured as a microcomputer centered around a CPU, and in addition to the CPU, includes a ROM for storing processing programs, a RAM for temporarily storing data, an input port, an output port, and a communication port. The engine ECU 24 receives signals from various sensors required for controlling the operation of the engine 22, such as a crank angle θcr from a crank position sensor 23a that detects the rotational position of a crankshaft 23 of the engine 22, via the input port. The engine ECU 24 outputs various control signals for controlling the operation of the engine 22 via the output port. The engine ECU 24 calculates the rotation speed Ne of the engine 22 based on the crank angle θcr of the engine 22 from the crank position sensor 140.

[0016] The starter motor 25 is connected to a crankshaft 23 serving as an output shaft of the engine 22. The starter motor 25 receives power from a low-voltage battery 60 to crank the engine 22. The crankshaft 23 of the engine 22 is also connected to the input side of a damper 28 serving as a torsion element. A pulley 23b is attached to the crankshaft 23 of the engine 22.

[0017] The motor 30 is configured as, for example, a synchronous generator motor. A pulley 30b is attached to the rotating shaft of the motor 30. The pulley 30b is rotationally driven by power transmitted by a belt 31 that is wound around a pulley 23b attached to the crankshaft 23 of the engine 22. The motor 30 is driven by an inverter 32. The inverter 32 is connected to a high-voltage power line 61. The motor 30 is rotationally driven by the main ECU 70 controlling the switching of multiple switching elements of the inverter 32.

[0018] The automatic transmission 40 includes a torque converter 43, an automatic transmission 45 with, for example, six speeds, and a hydraulic circuit (not shown). The torque converter 43 is configured as a typical fluid-type transmission device. The torque converter 43 amplifies the torque of the input shaft 41 connected to the rotating shaft of the motor 30 and transmits it to an intermediate rotating shaft 44, which is the input shaft of the automatic transmission 45, or transmits the torque directly without amplifying it. The automatic transmission 45 is connected to the intermediate rotating shaft 44 and to an output shaft 42, which is connected to a drive shaft 46. The automatic transmission 45 has multiple planetary gears and multiple hydraulically driven friction engagement elements (clutches, brakes). The drive shaft 46 is connected to drive wheels 49a, 49b via an axle 48 and a rear differential gear 47. The automatic transmission 45 transmits power between the intermediate rotary shaft 44 and the output shaft 42, for example, by forming forward speeds from 1st to 6th speeds and reverse speeds by engaging and disengaging a plurality of friction engagement elements.

[0019] The high-voltage battery 50 is configured as, for example, a lithium-ion battery or a nickel-metal hydride battery. The high-voltage battery 50 is connected to a high-voltage power line 51 that is connected to the inverter 32. A relay 52 is attached to the high-voltage power line 51 for disconnecting the high-voltage battery 50. The low-voltage battery 60 is configured as, for example, a lead battery having a lower rated voltage than the high-voltage battery 50. The low-voltage battery 60 is connected to the low-voltage power line 51 that is connected to the starter motor 25 and auxiliary equipment 68. A DC / DC converter 66 is connected to the high-voltage power line 51 and the low-voltage power line 61. The DC / DC converter 66 is controlled by the main ECU 70 to step down the power from the high-voltage power line 51 and supply it to the low-voltage power line 61, or to step up the power from the low-voltage power line 61 and supply it to the high-voltage power line 51. A smoothing capacitor 54 is attached to the high-voltage power line 51, and a smoothing capacitor 64 is attached to the low-voltage power line 61.

[0020] Although not shown, the main ECU 70 is configured as a microcomputer centered around a CPU, and in addition to the CPU, it is equipped with a ROM for storing processing programs, a RAM for temporarily storing data, an input port, an output port, and a communication port.

[0021] The main ECU 70 receives, via an input port, the rotational position φm of the rotor of the motor 30 from a rotational position sensor (not shown) that detects the rotational position of the rotor of the motor 30, the rotational speed Np of the drive shaft 46 from a rotational speed sensor 46a attached to the drive shaft 46, etc. The main ECU 70 also receives, via the input port, the battery voltage Vb from a voltage sensor 50a attached to the output terminal of the high-voltage battery 50, the charge / discharge current Ib from a current sensor 50b, the battery temperature Tb from a temperature sensor 60c attached to the high-voltage battery 50, the high-voltage system voltage VH from a voltage sensor 54a attached to the high-voltage system power line 51, and the low-voltage system voltage VL from a voltage sensor 64a attached to the low-voltage system power line 61. The main ECU 70 also receives, via the input port, an ignition signal from an ignition switch 80, a shift position SP from a shift position sensor 82 that detects the operating position of a shift lever 81, an accelerator opening Acc from an accelerator pedal position sensor 84 that detects the amount of depression of an accelerator pedal 83, a brake pedal position BP from a brake pedal position sensor 86 that detects the amount of depression of a brake pedal 85, and a vehicle speed V from a vehicle speed sensor 88.

[0022] The main ECU 70 outputs, via its output ports, a control signal to the starter motor 25, a control signal to the inverter 32, a drive control signal to the relay 52, a control signal to the automatic transmission 40, a control signal to the DC / DC converter 66, a drive control signal to the auxiliary equipment 68, and the like.

[0023] The main ECU 70 is connected via a communication port to the engine ECU 24. The main ECU 70 calculates the state of charge (SOC) of the high-voltage battery 60 based on the voltage VH of the high-voltage battery 60, the current Ib flowing through the high-voltage battery 60, and the like.

[0024] While the automobile 20 is traveling, the main ECU 70 sets a drive shaft torque demand Td* required of the drive shaft 46 based on the accelerator pedal position Acc and the vehicle speed V, and also sets a motor torque demand Tm* to be output from the motor 30. The main ECU 70 calculates an effective torque Teg* as the sum of the torque obtained by converting the drive shaft torque Td* to the crankshaft 23 and the torque obtained by converting the motor torque Tm* to the crankshaft 23, and transmits the effective torque Teg* to the engine ECU 24. The engine ECU 24 controls the intake air amount, fuel injection, and ignition so that the received effective torque Teg* is output from the engine 22. The main ECU 70 controls the switching elements of the inverter 32 so that the motor torque demand Tm* is output from the motor 30. The main ECU 70 controls the automatic transmission 40 to shift to a gear position determined by a gear shift map in which gear positions are divided according to the vehicle speed V and the drive shaft torque demand Td*.

[0025] Next, the operation of the automobile 20 of this embodiment, particularly the operation when performing batteryless control by disconnecting the high-voltage battery 50, will be described. FIG.

[0026] When the batteryless processing is executed, the main ECU 70 first determines whether or not a malfunction has occurred in the high-voltage battery 50 (step S100). The determination of whether or not a malfunction has occurred in the high-voltage battery 50 can be made by checking the value of a malfunction determination flag that is set to 1 when a malfunction has occurred in the high-voltage battery 50 by a malfunction diagnosis processing (not shown) that diagnoses a malfunction in the high-voltage battery 50. If it is determined that no malfunction has occurred in the high-voltage battery 50, the main ECU 70 determines that batteryless control is unnecessary and ends this processing.

[0027] If it is determined in step S100 that a fault has occurred in the high-voltage battery 50, the operation of the DC / DC converter 66 is stopped (step S110), the operation of the motor 30 is stopped (step S120), and the relay 52 is turned off to disconnect the high-voltage battery 50 (step S130).

[0028] Next, it is determined whether or not there is voltage in the high-voltage system (step S140). This determination can be made, for example, by determining whether or not the high-voltage system voltage VH from a voltage sensor 54a attached to the high-voltage system power line 51 is equal to or greater than a first threshold. The first threshold can be determined in advance as a voltage on the high-voltage system power line 51 that is sufficient to start the motor 30 with the charge stored in the capacitor 54.

[0029] If it is determined in step S140 that there is voltage in the high-voltage system (high-voltage system voltage VH is equal to or greater than the first threshold), inverter 32 is controlled to start motor 30 using the charge stored in capacitor 34 (step S190), regenerative control is initiated to cause started motor 30 to function as a generator to generate electricity (step S200), and DC / DC converter 66 is controlled to step down the power on high-voltage system power line 51 (power generated by motor 30) and supply it to low-voltage system power line 61 (step S210). This batteryless control, consisting of the power generation control of motor 30 and the step-down control of DC / DC converter 66, continues until the ignition switch is turned off (step S220) and ends when the ignition switch is turned off.

[0030] If it is determined in step S140 that there is no voltage in the high-voltage system (high-voltage system voltage VH is less than the first threshold), it is then determined whether the low-voltage system is sufficient (step S150). The determination of whether the low-voltage system is sufficient can be made, for example, by determining whether the low-voltage system voltage VL from voltage sensor 64a attached to low-voltage system power line 61 is equal to or greater than a second threshold. The second threshold can be predetermined as a voltage at which the DC / DC converter 66 can boost the voltage of low-voltage system power line 61 to a level sufficient to start motor 30 and supply it to high-voltage system power line 51.

[0031] If it is determined in step S150 that the low-voltage system is sufficient (low-voltage system voltage VL is equal to or greater than the second threshold), the controller 10 controls DC / DC converter 66 to boost the power on low-voltage power line 61 (power supplied from low-voltage battery 60) and supply it to high-voltage power line 51 (step S160). The controller 10 then controls inverter 32 to start motor 30 using the power supplied from the low-voltage system (step S190), starts regenerative control to cause started motor 30 to function as a generator and generate power (step S200), and controls DC / DC converter 66 to lower the power on high-voltage power line 51 (power generated by motor 30) and supply it to low-voltage power line 61 (step S210). This batteryless control, consisting of the power generation control of motor 30 and the step-down control of DC / DC converter 66, continues until the ignition switch is turned off (step S220) and ends when the ignition switch is turned off.

[0032] If it is determined in step S150 that the low-voltage system is insufficient (low-voltage system voltage VL is less than the second threshold), a command is issued to engine ECU 24 to increase engine 22 rotation speed Ne (step S170), thereby increasing the engine 22 rotation speed Ne and increasing the back electromotive force of motor 30 (step S180). As the back electromotive force of motor 30 increases, charge is stored in capacitor 34 attached to high-voltage system power line 51. Inverter 32 is controlled to start motor 30 using the charge stored in capacitor 34 (step S190), regenerative control is initiated to cause started motor 30 to function as a generator and generate electricity (step S200), and DC / DC converter 66 is controlled to reduce the power of high-voltage system power line 51 (power generated by motor 30) and supply it to low-voltage system power line 61 (step S210). The batteryless control consisting of the power generation control of the motor 30 and the voltage step-down control of the DC / DC converter 66 continues until the ignition switch is turned off (step S220), and ends when the ignition switch is turned off.

[0033] In the main ECU 70 (on-board control device) mounted on the automobile 20 of the embodiment described above, when a failure occurs in the high-voltage battery 50, the relay 52 is turned off to disconnect the high-voltage battery 50, and the motor 30 is started based on the voltage of the high-voltage system. Since the motor 30 is started based on the voltage of the high-voltage system in this way, the motor 30 can be started more appropriately. When the motor 30 is started, batteryless control is executed in which the motor 30 is controlled to function as a generator and the DC / DC converter 66 is controlled to reduce the power generated by the motor 30 and supply it to the low-voltage power line 61. This makes it possible to execute batteryless control more reliably.

[0034] In the main ECU 70 (on-board control device) mounted on the automobile 20 of the embodiment, the operation of starting the motor 30 based on the voltage of the high-voltage system is as follows: first, it determines whether or not there is voltage in the high-voltage system (whether or not the high-voltage system voltage VH is equal to or greater than a first threshold); if it determines that there is voltage in the high-voltage system (whether the high-voltage system voltage VH is equal to or greater than the first threshold), it starts the motor 30 using the charge stored in the capacitor 34; if it determines that there is no voltage in the high-voltage system (the high-voltage system voltage VH is less than the first threshold), it determines whether or not the low-voltage system is sufficient (whether or not the low-voltage system voltage VL is equal to or greater than a second threshold); if it determines that the low-voltage system is sufficient (the low-voltage system voltage VL is equal to or greater than the second threshold), it controls the DC / DC converter 66 to boost the power supplied from the low-voltage battery 60 and supply it to the high-voltage system power line 51, and starts the motor 30 using the power supplied from the low-voltage system. When it is determined that the low voltage system is insufficient (the low voltage system voltage VL is less than the second threshold), the rotation speed Ne of the engine 22 is increased to increase the back electromotive force of the motor 30, and the motor 30 is started using the charge stored in the capacitor 34 as the back electromotive force of the motor 30 increases. By starting the motor 30 based on the voltage of the high voltage system in this way, the motor 30 can be started more reliably.

[0035] In the automobile 20 of the embodiment, the engine 22 and the motor 30 are connected by two pulleys 23b, 30b and a belt 31 wound around both pulleys 23b, 30b. However, the engine 22 and the motor 30 may be connected by a chain mechanism, via a gear mechanism, or directly.

[0036] The correspondence between the main elements of the embodiment and the main elements of the invention described in the "Means for Solving the Problems" section will be described below. In the embodiment, the engine 22 corresponds to the "engine," the motor 30 corresponds to the "electric motor," the high-voltage battery 50 corresponds to the "high-voltage battery," the low-voltage battery 60 corresponds to the "low-voltage battery," the auxiliary device 68 corresponds to the "auxiliary device," the DC / DC converter 66 corresponds to the "DC / DC converter," the relay 52 corresponds to the "relay," the capacitor 34 corresponds to the "capacitor," and the main electronic control unit (main ECU) 70 corresponds to the "on-vehicle control device."

[0037] The correspondence between the main elements of the embodiments and the main elements of the invention described in the "Means for Solving the Problem" section is not intended to limit the elements of the invention described in the "Means for Solving the Problem" section, since the embodiments are merely examples for specifically explaining the invention described in the "Means for Solving the Problem" section. In other words, the interpretation of the invention described in the "Means for Solving the Problem" section should be based on the description in that section, and the embodiments are merely specific examples of the invention described in the "Means for Solving the Problem" section.

[0038] The above describes forms (embodiments) for implementing the present disclosure, but the present disclosure is not limited to these embodiments in any way, and it goes without saying that the present disclosure can be implemented in various forms within the scope that does not deviate from the gist of the present disclosure. [Industrial Applicability]

[0039] The present disclosure is applicable to the manufacturing industry of in-vehicle control devices, etc. [Explanation of symbols]

[0040] 20 automobile, 22 engine, 23 crankshaft, 23a crank position sensor, 23b pulley, 24 engine ECU, 25 starter motor, 28 damper, 30 motor, 30b pulley, 31 belt, 32 inverter, 40 automatic transmission, 41 input shaft, 42 output shaft, 43 torque converter, 44 intermediate rotating shaft, 45 automatic transmission, 46 drive shaft, 46a rotation speed sensor, 47 rear differential gear, 48 axle, 49a, 49b drive wheel, 50 high-voltage battery, 50a voltage sensor, 50b current sensor, 50c temperature sensor, 51 high-voltage power line, 52 relay, 54 capacitor, 54a voltage sensor, 60 low-voltage battery, 61 low-voltage power line, 64 capacitor, 64a voltage sensor, 66 DC / DC converter, 68 auxiliary equipment, 70 main electronic control unit (main ECU), 80 ignition switch, 81 shift lever, 82 shift position sensor, 83 accelerator pedal, 84 accelerator pedal position sensor, 85 brake pedal, 86 brake pedal position sensor, 88 vehicle speed sensor.

Claims

1. The engine and an electric motor capable of generating electricity connected to a crankshaft of the engine; a high-voltage battery connected to the electric motor by a high-voltage power line; A low voltage battery; an auxiliary device that receives power via a low-voltage power line connected to the low-voltage battery; a DC / DC converter connected to the high-voltage power line and the low-voltage power line; a relay attached to the high-voltage power line on the high-voltage battery side of the DC / DC converter; a capacitor attached to the high-voltage power line on the DC / DC converter side of the relay; An in-vehicle control device mounted on an automobile comprising: When a failure occurs in the high-voltage battery, the relay is turned off to disconnect the high-voltage battery and perform batteryless control, and when the voltage of the high-voltage power line is equal to or higher than a first threshold, the electric motor is started using the charge stored in the capacitor, and when the voltage of the high-voltage power line is lower than the first threshold, the DC / DC converter boosts the power of the low-voltage power line and supplies it to the high-voltage power line to start the electric motor.

1. An in-vehicle control device comprising:

2. An in-vehicle control device according to claim 1, When the batteryless control is performed, if the voltage of the high-voltage power line is less than the threshold value and the voltage of the low-voltage power line is less than a second threshold value, the voltage of the high-voltage power line is increased by the back electromotive force of the electric motor in conjunction with an increase in the rotation speed of the engine, thereby storing charge in the capacitor, and the electric motor is started using the charge stored in the capacitor. In-vehicle control device.

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