JP5699615B2 - Hybrid car - Google Patents

Description

  The present invention relates to a hybrid vehicle, and more specifically, an internal combustion engine capable of outputting driving power, and heat exchange between the heat of the exhaust from the internal combustion engine and the cooling medium of the internal combustion engine attached to the exhaust system of the internal combustion engine. An exhaust heat recovery device to be performed, a cooling device for circulating a cooling medium in a circulation flow path including the internal combustion engine and the exhaust heat recovery device by driving an electric pump, an electric motor capable of outputting traveling power, and driving the electric motor A drive voltage system connected to an inverter for a motor, a secondary battery, a battery voltage system to which a secondary battery is connected via a relay and an electric pump is connected, and a drive voltage system to which an inverter for the motor is connected The booster converter that adjusts the voltage within the range of the voltage of the battery voltage system or more and exchanges power between the battery voltage system and the drive voltage system, and the converter attached to the drive voltage system. And a capacitor, a hybrid car with a.

  Conventionally, this type of hybrid vehicle includes a traveling engine and motor generator, a main battery, a converter capable of boosting the power from the main battery and supplying it to the motor generator, and in parallel with the converter as viewed from the main battery. An air conditioner (A / C) compressor that is connected, a main relay that controls the supply and cut-off of power from the main battery to the motor generator and A / C compressor, and a capacitor that is attached to the motor generator side from the converter When the IG key is turned off, the main relay is turned off and the drive system inverter is stopped, and the converter is controlled so that the capacitor charge is supplied to the A / C compressor. / C compressor discharge has been proposed ( In example, see Patent Document 1). In this hybrid vehicle, the durability of the drive system is improved by such control as compared with that in which the residual charge is discharged from the converter on the motor generator side (drive system).

JP 2003-230269 A

  In addition to the engine, motor generator, main battery, converter, main relay, condenser, etc. described above, an exhaust heat recovery device that uses the heat of the exhaust from the engine to heat the engine coolant, or a converter as viewed from the main battery In a hybrid vehicle equipped with a cooling device that circulates cooling water in a circulation flow path including an engine and an exhaust heat recovery device by driving an electric pump connected in parallel, when the IG key is turned off, the exhaust heat recovery device When the temperature is high, it is conceivable to cool the exhaust heat recovery device by circulating the cooling water in the circulation flow path by driving the electric pump using the residual charge of the capacitor as in the hybrid vehicle described above. Depending on the voltage of the capacitor (the amount of residual charge), the exhaust heat recovery device may not be sufficiently cooled.

  The main purpose of the hybrid vehicle of the present invention is to effectively use the charge of the capacitor and more reliably cool the exhaust heat recovery device when the temperature of the exhaust heat recovery device is high when the ignition is off.

  The hybrid vehicle of the present invention employs the following means in order to achieve the main object described above.

The hybrid vehicle of the present invention
An internal combustion engine capable of outputting driving power, an exhaust heat recovery device attached to an exhaust system of the internal combustion engine for exchanging heat between exhaust heat from the internal combustion engine and a cooling medium of the internal combustion engine, and electric A cooling device that circulates the cooling medium in a circulation flow path including the internal combustion engine and the exhaust heat recovery device by driving a pump, an electric motor that can output power for traveling, and an inverter for the electric motor that drives the electric motor; The drive voltage system is connected to a secondary battery, a battery voltage system to which the secondary battery is connected via a relay and to which the electric pump is connected, and a drive voltage system to which the inverter for the motor is connected. A step-up converter that adjusts the voltage within a range equal to or higher than the voltage of the battery voltage system and exchanges power between the battery voltage system and the drive voltage system, and is attached to the drive voltage system A capacitor that is, in the hybrid vehicle equipped with,
When the exhaust heat recovery device is required to be cooled when the ignition is turned off, when the voltage of the capacitor is equal to or higher than the voltage of the secondary battery, the charge of the capacitor is transferred to the boost converter with the relay turned off. The electric pump, the step-up converter, and the relay are controlled so that the electric pump is driven, and when the voltage of the capacitor is less than the voltage of the secondary battery, the relay is in an on state. Control means for controlling the electric pump and the relay so that the electric pump is driven using the power of the secondary battery;
It is a summary to provide.

  In the hybrid vehicle of the present invention, when the ignition is turned off, cooling of the exhaust heat recovery device that is attached to the exhaust system of the internal combustion engine and performs heat exchange between the heat of the exhaust from the internal combustion engine and the cooling medium of the internal combustion engine is performed. When required, when the voltage of the capacitor is equal to or higher than the voltage of the secondary battery, the electric pump and the boost converter are configured so that the electric pump is driven using the charge of the capacitor via the boost converter with the relay turned off. Control the relay. On the other hand, when the voltage of the capacitor is lower than the voltage of the secondary battery, the electric pump and the relay are controlled so that the electric pump is driven using the power of the secondary battery while the relay is on. That is, when the voltage of the capacitor is equal to or higher than the voltage of the secondary battery, the exhaust heat recovery device is cooled by circulating the cooling medium in the circulation flow path by driving the electric pump using the electric charge of the capacitor. When the voltage is lower than the voltage of the secondary battery, the electric pump is driven using the power of the secondary battery to circulate the cooling medium in the circulation flow path to cool the exhaust heat recovery device. Thereby, the electric charge of the capacitor can be effectively used and the exhaust heat recovery device can be cooled more reliably.

1 is a configuration diagram showing an outline of a configuration of a hybrid vehicle 20 as an embodiment of the present invention. 1 is a configuration diagram showing an outline of a configuration of an electric system included in a hybrid vehicle 20; 5 is a flowchart illustrating an example of an ignition-off time processing routine executed by a hybrid electronic control unit 70.

  Next, the form for implementing this invention is demonstrated using an Example.

  FIG. 1 is a configuration diagram showing an outline of the configuration of a hybrid vehicle 20 as an embodiment of the present invention, and FIG. 2 is a configuration diagram showing an outline of the configuration of an electric system included in the hybrid vehicle 20. As shown in the drawing, the hybrid vehicle 20 of the embodiment includes an engine 22 that uses gasoline or light oil as fuel, and is attached to the exhaust system of the engine 22 so that the heat of the exhaust from the engine 22 and the cooling water (long An exhaust heat recovery device 90 that performs heat exchange with a life coolant (LLC), a cooling device 100 that cools the engine 22 using cooling water, and an engine electronic control unit that controls the engine 22 (hereinafter referred to as the engine). ECU) 24, a planetary gear 30 having a carrier connected to the crankshaft 26 of the engine 22 and a ring gear connected to a drive shaft 32 connected to drive wheels 39a and 39b via a differential gear 38, for example, synchronous power generation The rotor is connected to the sun gear of the planetary gear 30 configured as an electric motor. The motor MG1, the motor MG2 configured as a synchronous generator motor, for example, having a rotor connected to the drive shaft 32, inverters 41, 42 for driving the motors MG1, MG2, and the inverters 41, 42 for switching control. Thus, a motor electronic control unit (hereinafter referred to as a motor ECU) 40 for driving and controlling the motors MG1 and MG2, a battery 50 configured as, for example, a lithium ion secondary battery, and a battery electronic control unit for managing the battery 50 ( Hereinafter, the power line (hereinafter referred to as the battery ECU) 52, the power line (hereinafter referred to as the high voltage system power line) 54a connected to the inverters 41 and 42, and the battery 50 via the system main relay 56 (hereinafter referred to as the battery). Connected to the power line 54b). A step-up converter 55 that adjusts the voltage of the system power line 54a within a range equal to or higher than the voltage of the battery voltage system power line 54b and exchanges power between the high voltage system power line 54a and the battery voltage system power line 54b; A smoothing capacitor 57 connected to the positive and negative buses of the high voltage system power line 54a, and a capacitor 57 connected to the positive and negative buses of the high voltage system power line 54a to discharge the electric charge of the capacitor 57. A discharge resistor 59, a smoothing capacitor 58 connected to the positive and negative buses of the battery voltage system power line 54b, and a hybrid electronic control unit 70 for controlling the entire vehicle are provided.

  The exhaust heat recovery device 90 is a heat exchanging portion capable of exchanging heat between the exhaust heat from the engine 22 and the cooling water, and a first leading to the heat exchanging portion side as an exhaust path passing through the exhaust heat recovery device 90 A flow path switching valve that switches between the first path and the second path that passes through the second path. In the exhaust heat recovery apparatus 90, when the cooling water temperature Tw of the cooling water is low and warm-up is required, such as when the system is started, the flow path switching valve is closed and the exhaust from the engine 22 is guided to the heat exchange unit side. Thus, the cooling water is heated by the heat exchange between the heat of the exhaust gas and the cooling water in the heat exchanging section, and warm-up is promoted. When the warm-up is completed, the flow switching valve is opened and the exhaust from the engine 22 is allowed to pass through without being guided to the heat exchanging portion, so that the heat exchange between the heat of the exhaust and the cooling water is performed in the heat exchanging portion. Will not be done so much.

  The cooling device 100 includes a radiator 102 that performs heat exchange between the cooling water and outside air, and an electric pump 106 that circulates the cooling water in the circulation passage 104 including the engine 22, the exhaust heat recovery device 90, and the radiator 102. . Here, the electric pump 106 is connected to the battery voltage system power line 54b (see FIG. 2). In this cooling device 100, the cooling water that has been heat-exchanged with the outside air by the radiator is supplied to the engine 22 and the exhaust heat recovery device 90 by the electric pump 106, thereby suppressing overheating of the engine 22 and the exhaust heat recovery device 90. ing.

  As shown in FIG. 2, the boost converter 55 is configured as a boost converter including two transistors T31 and T32, two diodes D31 and D32 connected in parallel to the transistors T31 and T32 in a reverse direction, and a reactor L. . The two transistors T31 and T32 are respectively connected to the positive bus of the high voltage system power line 54a and the negative bus of the high voltage system power line 54a and the battery voltage system power line 54b, and the reactor L is connected to the connection point. Has been. Further, the positive terminal and the negative terminal of the battery 50 are connected to the reactor L and the negative bus of the battery voltage system power line 54b via the system main relay 56, respectively. Therefore, by turning on / off the transistors T31 and T32, the power of the battery voltage system power line 54b is boosted and supplied to the high voltage system power line 54a, or the power of the high voltage system power line 54a is reduced to reduce the battery voltage. Or can be supplied to the system power line 54b. Hereinafter, the transistor T31 may be referred to as an upper arm and the transistor T32 may be referred to as a lower arm.

  The engine ECU 24 not only controls the drive of the engine 22, but also calculates the rotational speed of the crankshaft 26, that is, the rotational speed Ne of the engine 22 based on the crank position from the crank position sensor. Further, the motor ECU 40 not only performs switching control of the switching elements of the inverters 41 and 42 but also calculates the rotational speeds Nm1 and Nm2 of the motors MG1 and MG2 based on a signal from the rotational position detection sensor. The battery ECU 52 receives signals necessary for managing the battery 50, such as a voltage Vb between terminals from the voltage sensor 51a installed between the terminals of the battery 50, and a current sensor 51b attached to the output terminal of the battery 50. The charge / discharge current Ib, the battery temperature Tb from the temperature sensor 51c attached to the battery 50, and the like are input. The battery ECU 52 is a power storage that is a ratio of the amount of power stored in the battery 50 based on the integrated value of the charge / discharge current Ib detected by the current sensor 51b in order to manage the battery 50 to the total capacity (power storage capacity). The ratio SOC is calculated, and the input / output limits Win and Wout, which are the maximum allowable power that may charge / discharge the battery 50, are calculated based on the calculated storage ratio SOC and the battery temperature Tb.

  The hybrid electronic control unit 70 is configured as a microprocessor centered on a CPU (not shown), and includes a ROM, a RAM, an input / output port, and a communication port in addition to the CPU. In the hybrid electronic control unit 70, the voltage of the capacitor 57 (the voltage of the high voltage system power line 54 a) VH from the voltage sensor 57 a attached between the terminals of the capacitor 57 and the voltage sensor attached between the terminals of the capacitor 58. The voltage of the capacitor 58 from 58a (the voltage of the battery voltage system power line 54b) VL, the cooling water temperature Tw from the temperature sensor 108 attached in the vicinity of the outlet of the exhaust heat recovery device 90 in the circulation flow path 104, from the ignition switch 80 The ignition position signal, the shift position SP from the shift position sensor 82 that detects the operation position of the shift lever, the accelerator opening degree Acc from the accelerator pedal position sensor 84 that detects the depression amount of the accelerator pedal, and the depression amount of the brake pedal are detected. break pedal A brake pedal position BP from Jishon sensor 86, a vehicle speed V from a vehicle speed sensor 88 is input through the input port. The hybrid electronic control unit 70 outputs a switching control signal to the transistors T31 and T32 of the boost converter 55, an on / off signal to the system main relay 56, a drive signal to the electric pump 106, and the like via an output port. . The hybrid electronic control unit 70 is connected to the engine ECU 24, the motor ECU 40, and the battery ECU 52 via a communication port, and exchanges various control signals and data with the engine ECU 24, the motor ECU 40, and the battery ECU 52.

  Next, the operation of the hybrid vehicle 20 of the embodiment configured as described above, particularly the operation when the ignition is turned off will be described. FIG. 3 is a flowchart showing an example of an ignition-off time processing routine executed by the hybrid electronic control unit 70 when the ignition is turned off. In the embodiment, when the execution of this routine is started after the ignition is turned off, the inverters 41 and 42 are stopped.

  When the ignition-off process routine is executed, the hybrid electronic control unit 70 first cools the exhaust heat recovery device 90 by using the cooling water temperature Tw from the temperature sensor 108 attached in the vicinity of the outlet of the exhaust heat recovery device 90. Compared with the threshold value Twref defined as the lower limit of the required temperature range (step S100), when the cooling water temperature Tw is equal to or higher than the threshold value Twref, it is determined that the exhaust heat recovery device 90 needs to be cooled, and the voltage sensor 57a Voltage VH of capacitor 57 is compared with terminal voltage Vb of battery 50 from voltage sensor 51a (step S110).

  When voltage VH of capacitor 57 is equal to or higher than terminal voltage Vb of battery 50, system main relay 56 is turned off (step S120), and the charge of capacitor 57 is supplied to battery voltage system power line 54b via boost converter 55. The boost converter 55 is driven and controlled (step S130), the electric pump 106 is driven and controlled (step S140), and the process returns to step S100. Here, the boost converter 55 is specifically controlled by switching the transistors T31 and T32 so that the charge of the capacitor 57 is stepped down by the boost converter 55 and supplied to the battery voltage power line 54b. It is. In this case, the electric pump 106 is driven using the electric charge of the capacitor 57 via the boost converter 55.

  On the other hand, when voltage VH of capacitor 57 is less than voltage Vb between terminals of battery 50, system main relay 56 is turned on (step S150), boost converter 55 is stopped (step S160), and electric pump 106 is driven and controlled. (Step S170), the process returns to step S100. In this case, the electric pump 106 is driven using the electric power of the battery 50.

  In this way, when the electric pump 106 is driven using the electric charge of the capacitor 57 or the electric power of the battery 50, the cooling water is circulated in the circulation flow path 104 and the cooling water temperature Tw becomes lower than the threshold value Twref, or the ignition. When the cooling water temperature Tw is lower than the threshold value Twref when turned off, the system main relay 56 is turned off when the system main relay 56 is on (step S180), and this routine is terminated. Thereafter, the electric charge of the capacitor 57 is discharged by the discharge resistor 59.

  Now, consider the case where the exhaust heat recovery device 90 is at a high temperature (the cooling water temperature Tw is equal to or greater than the threshold value Twref) and the voltage VH of the capacitor 57 is equal to or greater than the voltage Vb between the terminals of the battery 50 when the ignition is turned off. At this time, first, the electric pump 106 is driven using the electric charge of the capacitor 57 to circulate the cooling water in the circulation flow path 104. When the voltage VH of the capacitor 57 becomes lower than the voltage Vb between the terminals of the battery 50 before the cooling water temperature Tw becomes lower than the threshold value Twref, the charge of the capacitor 57 decreases, but the exhaust heat recovery device 90 continues to be cooled. The electric pump 106 is driven using the electric power of the battery 50 to circulate the cooling water in the circulation passage 104, and when the cooling water temperature Tw becomes lower than the threshold value Twref, the electric pump 106 End driving. On the other hand, when the cooling water temperature Tw becomes lower than the threshold value Twref before the voltage VH of the capacitor 57 becomes lower than the inter-terminal voltage Vb of the battery 50, it is determined that it is not necessary to continue cooling the exhaust heat recovery device 90. The driving of the pump 106 is finished. Therefore, when the exhaust heat recovery device 90 needs to be cooled, the electric charge of the capacitor 57 can be used more effectively than when the electric pump 106 is driven using only the electric power from the battery 50. 50 power consumption can be suppressed. In addition, the electric pump 106 is driven using only the electric charge of the capacitor 57 (the electric pump 106 is stopped when the voltage VH of the capacitor 57 becomes less than the voltage Vb between the terminals of the battery 50). The exhaust heat recovery device 90 can be cooled more reliably. From the above, it can be said that the electric charge of the capacitor can be used effectively and the exhaust heat recovery device 90 can be cooled more reliably.

  According to the hybrid vehicle 20 of the embodiment described above, the system main relay 56 is used when the voltage VH of the capacitor 57 is equal to or higher than the voltage Vb between the terminals of the battery 50 when the cooling water temperature Tw is equal to or higher than the threshold value Twref when the ignition is turned off. The electric pump 106, the boost converter 55, and the system main relay 56 are controlled so that the electric pump 106 is driven using the electric charge of the capacitor 57 via the boost converter 55 when the voltage is off, and the voltage VH of the capacitor 57 is When the voltage between the terminals is less than Vb, the system main relay 56 is turned on and the electric pump 106 and the system main relay 56 are controlled so that the electric pump 106 is driven using the electric power of the battery 50. Can exhaust heat with It is possible to cool the yield device more reliably.

  The correspondence between the main elements of the embodiment and the main elements of the invention described in the column of means for solving the problems will be described. In the embodiment, the engine 22 corresponds to the “internal combustion engine”, the exhaust heat recovery device 90 corresponds to the “exhaust heat recovery device”, the cooling device 100 having the electric pump 106 corresponds to the “cooling device”, and the motor MG2. Corresponds to the “motor”, the inverter 42 corresponds to the “motor inverter”, the battery 50 corresponds to the “secondary battery”, the boost converter 55 corresponds to the “boost converter”, and the system main relay 56 When the cooling water temperature Tw is equal to or higher than the threshold value Twref when the ignition switch is turned off and the voltage VH of the capacitor 57 is equal to or higher than the voltage Vb between the terminals of the battery 50, the system corresponds to the “relay”. When the main relay 56 is off, the electric pump 106 is driven using the charge of the capacitor 57 via the boost converter 55. The electric pump 106, the boost converter 55, and the system main relay 56 are controlled so that when the voltage VH of the capacitor 57 is less than the voltage Vb between the terminals of the battery 50, the system main relay 56 is turned on and the electric power of the battery 50 is used. The hybrid electronic control unit 70 that controls the electric pump 106 and the system main relay 56 so that the pump 106 is driven corresponds to “control means”.

  The correspondence between the main elements of the embodiment and the main elements of the invention described in the column of means for solving the problem is the same as that of the embodiment described in the column of means for solving the problem. Therefore, the elements of the invention described in the column of means for solving the problems are not limited. That is, the interpretation of the invention described in the column of means for solving the problems should be made based on the description of the column, and the examples are those of the invention described in the column of means for solving the problems. It is only a specific example.

  As mentioned above, although the form for implementing this invention was demonstrated using the Example, this invention is not limited at all to such an Example, In the range which does not deviate from the summary of this invention, it is with various forms. Of course, it can be implemented.

  The present invention is applicable to the hybrid vehicle manufacturing industry.

  20 hybrid vehicle, 22 engine, 24 engine electronic control unit (engine ECU), 26 crankshaft, 30 planetary gear, 32 drive shaft, 38 differential gear, 39a, 39b drive wheel, 40 motor electronic control unit (motor ECU), 41, 42 Inverter, 50 Battery, 51a Voltage sensor, 51b Current sensor, 51c Temperature sensor, 52 Battery electronic control unit (battery ECU), 54 Power line, 54a High voltage system power line, 54b Battery voltage system power line, 55 Boost converter, 56 system main relay, 57, 58 capacitor, 57a, 58a voltage sensor, 59 discharge resistance, 70 hybrid electronic control unit, 80 ignition switch, 82 shift positive Sensor, 84 accelerator pedal position sensor, 86 brake pedal position sensor, 88 vehicle speed sensor, 90 exhaust heat recovery device, 100 cooling device, 102 radiator, 104 circulation flow path, 106 electric pump, 108 temperature sensor, D31, D32 diode, L reactor, MG1, MG2 motor, T31, T32 transistors.

Claims (1)

An internal combustion engine capable of outputting driving power, an exhaust heat recovery device attached to an exhaust system of the internal combustion engine for exchanging heat between exhaust heat from the internal combustion engine and a cooling medium of the internal combustion engine, and electric A cooling device that circulates the cooling medium in a circulation flow path including the internal combustion engine and the exhaust heat recovery device by driving a pump, an electric motor that can output power for traveling, and an inverter for the electric motor that drives the electric motor; The drive voltage system is connected to a secondary battery, a battery voltage system to which the secondary battery is connected via a relay and to which the electric pump is connected, and a drive voltage system to which the inverter for the motor is connected. A step-up converter that adjusts the voltage within a range equal to or higher than the voltage of the battery voltage system and exchanges power between the battery voltage system and the drive voltage system, and is attached to the drive voltage system A capacitor that is, in the hybrid vehicle equipped with,
When the exhaust heat recovery device is required to be cooled when the ignition is turned off, when the voltage of the capacitor is equal to or higher than the voltage of the secondary battery, the charge of the capacitor is transferred to the boost converter with the relay turned off. The electric pump, the step-up converter, and the relay are controlled so that the electric pump is driven, and when the voltage of the capacitor is less than the voltage of the secondary battery, the relay is in an on state. Control means for controlling the electric pump and the relay so that the electric pump is driven using the power of the secondary battery;
A hybrid car with

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