JP4052256B2 - Temperature control device - Google Patents

Description

  The present invention relates to a temperature adjustment device, and more particularly to a temperature adjustment device that adjusts the temperature of an electric drive system that inputs and outputs power in an electric vehicle.

2. Description of the Related Art Conventionally, as this type of temperature control apparatus, an apparatus that performs on / off control of an electric pump that circulates cooling water based on the temperature of cooling water that cools a motor has been proposed (see, for example, Patent Document 1). In this device, when the temperature of the cooling water is lower than the predetermined temperature, the electric pump is turned off to stop the supply of the cooling water to the motor. When the temperature of the cooling water is higher than the predetermined temperature, the electric pump is turned on to cool the motor. The temperature of the motor is adjusted by supplying water.
Japanese Patent Laid-Open No. 11-22460

  In the above temperature control device, the temperature of the motor is adjusted by the on / off control of the electric pump. Therefore, the cooling water supply to the motor may be insufficient and the cooling may not be performed sufficiently, or the flow rate may be higher than necessary. If the cooling water is supplied to the motor, the power consumption of the electric pump may become excessive.

  The temperature control device of the present invention is intended to solve such problems and suppress power consumption of an electric pump that circulates a cooling medium while sufficiently cooling an electric drive system that inputs and outputs electric power in an electric vehicle. .

  The temperature control apparatus of the present invention employs the following means in order to achieve the above object.

The temperature control device of the present invention comprises:
A temperature adjustment device for adjusting the temperature of an electric drive system that inputs and outputs electric power in an electric vehicle,
A circulation path connected to the electric drive system;
An electric pump for circulating a cooling medium in the circulation path;
A heat exchanger provided in the circulation path for exchanging heat with the cooling medium;
Temperature detecting means for detecting the temperature of the cooling medium;
Based on the detected temperature of the cooling medium, at least a first flow rate at which the cooling medium flows through the heat exchanger at a laminar flow rate and a second flow rate at which the cooling medium flows through the heat exchanger at a turbulent flow rate. And a drive control means for driving and controlling the electric pump so that the flow rate can be switched.

  In the temperature control device of the present invention, the first flow rate of the cooling medium flowing through the heat exchanger in the laminar flow region and the second flow of the cooling medium flowing through the heat exchanger in the turbulent flow region based on the temperature of the cooling medium in the circulation path. The electric pump is driven and controlled so that the flow rate can be switched. When the cooling medium is circulated at a flow rate in the turbulent flow area, the heat exchange efficiency in the heat exchanger increases. By switching between the flow rate in the turbulent flow region and the flow rate in the laminar flow region based on the temperature, the power consumption of the electric pump can be suppressed while ensuring sufficient cooling of the electric drive system.

  In such a temperature control apparatus of the present invention, the drive control means drives and controls the electric pump so that the second flow rate is switched when the detected temperature of the cooling medium exceeds a first predetermined temperature, The electric pump can be driven and controlled to be switched to the first flow rate when the detected temperature of the cooling medium falls below a second predetermined temperature. In this aspect of the temperature control apparatus of the present invention, the second predetermined temperature may be the same temperature as the first predetermined temperature or a temperature lower than the second predetermined temperature.

  In the temperature adjusting device of the present invention, the drive control means may be means for stopping the driving of the electric pump when the detected temperature of the cooling medium is lower than a third predetermined temperature. In this way, the power consumption of the electric pump can be further suppressed.

  Furthermore, in the temperature control apparatus of the present invention, the electric drive system may be a system including an electric motor that can output power to the drive wheels and a drive circuit that drives the electric motor. If it carries out like this, an electric motor and a drive circuit can be cooled.

  Alternatively, in the temperature control device of the present invention, the electric vehicle includes an internal combustion engine, connected to the internal combustion engine, and formed as a flow path different from the circulation path, and the internal combustion engine A pump that is mechanically driven by the rotational force of the output shaft to circulate the cooling medium in the second circulation path, and a second heat exchange that is provided in the second circulation path and performs heat exchange with the cooling medium. It can also be provided with a vessel.

  Next, the best mode for carrying out the present invention will be described using examples.

  FIG. 1 is a configuration diagram showing an outline of a configuration of an electric vehicle 10 including a temperature control device 20 as an embodiment of the present invention. For convenience of explanation, first, the electric vehicle 10 including the temperature control device 20 of the embodiment will be briefly described, and then the temperature control device 20 of the embodiment will be described. As illustrated, the electric vehicle 10 includes an engine 12, a planetary gear mechanism 14 having a carrier connected to the crankshaft 13 of the engine 12, a motor MG1 capable of generating electricity connected to a sun gear of the planetary gear mechanism 14, and a planetary gear. The motor MG2 connected to the ring gear of the gear mechanism 14, the battery 17 that exchanges electric power with the motors MG1 and MG2 via the inverters 15 and 16, the entire automobile, and a part of the temperature control device 20 of the embodiment. It is comprised as a hybrid vehicle provided with the electronic control unit 40 which also functions. A drive shaft 18 is connected to the ring gear of the planetary gear mechanism 14, and drive wheels 19 a and 19 b are connected to the drive shaft 18 via a differential gear. Therefore, the power output to the drive shaft 18 is finally output to the drive wheels 19a and 19b.

  As shown in the figure, the temperature control device 20 of the embodiment includes a circulation path (not shown) of a cooling medium (cooling water) for cooling the motor / inverter formed in the motors MG1, MG2, and inverters 15 and 16. A circulation pipe 22 that forms a coolant, an electric water pump 24 that circulates cooling water through the circulation pipe 22, a radiator 26 that cools the cooling water using outside air, a cooling fan 28 that is attached to the radiator 26, and a circulation pipe A motor / inverter cooling system comprising a temperature sensor 29 mounted on the path 22 and a circulation path (not shown) for a cooling medium (cooling water) for engine cooling formed in the engine 12 are formed. And the circulation line 32 connected to the crankshaft 13 of the engine 22 and mechanically driven by the rotational force of the crankshaft 13. An engine cooling system comprising a water pump 34 for circulating the cooling water, a radiator 36 for cooling the cooling water by outside air, and a cooling fan 38 attached to the radiator 36, and an electronic control unit 40 for controlling these systems. With.

  The electronic control unit 40 is configured as a microprocessor centered on the CPU 42, and includes a ROM 44 that stores a processing program, a RAM 46 that temporarily stores data, and an input / output port (not shown), in addition to the CPU 42. The electronic control unit 40 includes a signal relating to the operating state of the engine 22 and the motors MG1 and MG2 for controlling the driving of the engine 22 and the motors MG1 and MG2, and cooling water for cooling the motor and inverter detected by the temperature sensor 29. The temperature (cooling water temperature) Tw and the like are input via the input port. Further, the electronic control unit 40 controls the engine 22, the control signals of the switching elements of the inverters 15 and 16 for controlling the motors MG 1 and MG 2, and the drive for driving the electric water pump 24. A signal, a drive signal for driving the cooling fans 28 and 38, and the like are output via the output port.

  Next, the operation of the temperature control apparatus 20 of the embodiment configured in this way will be described. FIG. 2 is a flowchart illustrating an example of a temperature adjustment processing routine executed by the electronic control unit 40 of the temperature adjustment apparatus 20 according to the embodiment. This routine is repeatedly executed every predetermined time (for example, every 20 msec).

  When the temperature adjustment processing routine is executed, the CPU 42 of the electronic control unit 40 first reads the temperature (cooling water temperature) Tw for cooling the motor / inverter detected by the temperature sensor 29 (step S100). The cooling water temperature Tw is compared with the threshold value Twref (step S110). Here, the threshold value Twref is a threshold value for determining whether or not the electric water pump 24 needs to be driven to cool the motors MG1 and MG2 and the inverters 15 and 16, and the motors MG1 and MG2 and the inverters 15 and 16 are determined. It is determined by. When the cooling water temperature Tw is equal to or lower than the threshold value Twref, it is determined that cooling of the motors MG1, MG2 and the inverters 15, 16 is not necessary, the electric water pump 26 is turned off (step S120), and this routine is terminated.

  When the cooling water temperature Tw is larger than the threshold value Twref, the target flow rate Q * of the cooling water is set based on the cooling water temperature Tw (step S130), and the electric water pump 24 is configured so that the cooling water circulates at the set target flow rate Q *. Is controlled (step S140), and this routine is terminated. Here, in setting the target flow rate Q *, in the embodiment, when the relationship between the cooling water temperature Tw and the target flow rate Q * is obtained in advance and stored in the ROM 44 as a target flow rate setting map, the cooling water temperature Tw is given. This is done by deriving and setting the corresponding target flow rate Q * from the target flow rate setting map. An example of this target flow rate setting map is shown in FIG. As shown in the figure, the target flow rate Q * is set so that the cooling water circulates in the laminar flow region when the cooling water temperature Tw is lower than the predetermined temperature T0, and the cooling water is in the turbulent flow region when the cooling water temperature Tw is equal to or higher than the predetermined temperature T0. Set to circulate. FIG. 4 is an explanatory diagram showing the relationship between the flow rate of the cooling water flowing through the radiator 26 and the cooling capacity of the radiator 26. As shown in the figure, when the cooling water is circulated at a turbulent flow rate, the heat exchange efficiency of the cooling water in the radiator 26 is greatly improved, and the cooling of the motors MG1, MG2 and the inverters 15, 16 is promoted. On the other hand, the flow resistance increases and the power consumed by the electric water pump 24 becomes relatively large. When the cooling water is circulated at a laminar flow rate, the heat exchange efficiency of the radiator 26 is greatly reduced, but the power consumption of the electric water pump 26 can be suppressed while the motors MG1 and MG2 and the inverters 15 and 16 are cooled to some extent. Thus, by setting the target flow rate Q * so that the cooling water circulates at a laminar flow rate when the cooling water temperature Tw is lower than the predetermined temperature T0, the motors MG1, MG2 and the inverters 15, 16 are excessively cooled. It suppresses to improve the energy efficiency of the device.

  According to the temperature control device 20 of the embodiment described above, the target flow rate Q * is switched between a laminar flow region flow rate and a turbulent flow region flow rate based on the cooling water temperature (cooling water temperature Tw) for motor / inverter cooling. Therefore, it is possible to suppress power consumption of the electric water pump 24 that circulates the cooling water while ensuring sufficient cooling of the motors MG1 and MG2 and the inverters 15 and 16. As a result, the energy efficiency of the entire apparatus can be further improved.

  In the temperature control device 20 of the embodiment, when the cooling water temperature Tw is less than the threshold value Twref, the electric water pump 24 is turned off to stop the circulation of the cooling water, but the electric water pump 24 is not turned off even if the temperature is lower than the threshold value Twref. The cooling water may be circulated in the laminar flow area.

  In the temperature control device 20 of the embodiment, the flow rate in the laminar flow region and the flow rate in the turbulent flow region are switched at the predetermined temperature T0. However, hysteresis may be provided when the cooling water temperature Tw rises and falls. Further, in the temperature control device 20 of the embodiment, as shown in FIG. 3, the target flow rate Q * in the laminar flow region is constant regardless of the cooling water temperature Tw above the predetermined temperature, and the target flow rate Q * in the turbulent flow region is cooled. Although it is constant regardless of the water temperature Tw, it may be not constant such as changing in a stepped manner or changing proportionally according to the cooling water temperature Tw. Furthermore, in the temperature control apparatus 20 of the embodiment, the flow rate in the transition region is not used as the target flow rate Q *, but may be used.

  In the embodiment, the temperature adjusting device 20 is described as applied to the electric vehicle 10 including the engine 22 and the motors MG1 and MG2. However, the temperature adjusting device 20 may be applied to a normal electric vehicle including only a traveling motor. It is.

  The best mode for carrying out the present invention has been described with reference to the embodiments. However, the present invention is not limited to these embodiments, and various modifications can be made without departing from the gist of the present invention. Of course, it can be implemented in the form.

It is a block diagram which shows the outline of a structure of the electric vehicle 10 provided with the temperature control apparatus 20 as one Embodiment of this invention. It is a flowchart which shows an example of the temperature control process routine performed by the electronic control unit 40 of the temperature control apparatus 20 of an Example. It is explanatory drawing which shows an example of the map for target flow volume setting. FIG. 5 is an explanatory diagram showing the relationship between the flow rate of cooling water and the cooling effect of the radiator 26.

Explanation of symbols

DESCRIPTION OF SYMBOLS 10 Electric vehicle, 12 Engine, 13 Crankshaft, 14 Planetary gear mechanism, 15, 16 Inverter, 17 Battery, 18 Drive shaft, 19a, 19b Drive wheel, 20 Temperature control device, 22 Circulation line, 24 Electric water pump, 26 Radiator, 28 Cooling fan, 29 Temperature sensor, 32 Circulation line, 34 Water pump, 36 Radiator, 38 Cooling fan, 40 Electronic control unit, 42 CPU, 44 ROM, 46 RAM, MG1, MG2 Motor.

Claims (6)

A temperature adjustment device for adjusting the temperature of an electric drive system that inputs and outputs electric power in an electric vehicle,
A circulation path connected to the electric drive system;
An electric pump for circulating a cooling medium in the circulation path;
A heat exchanger provided in the circulation path for exchanging heat with the cooling medium;
Temperature detecting means for detecting the temperature of the cooling medium;
Based on the detected temperature of the cooling medium, at least a first flow rate at which the cooling medium flows through the heat exchanger at a laminar flow rate and a second flow rate at which the cooling medium flows through the heat exchanger at a turbulent flow rate. And a drive control means for driving and controlling the electric pump so that the flow rate can be switched.   The drive control means drives and controls the electric pump so as to switch to the second flow rate when the detected temperature of the cooling medium exceeds a first predetermined temperature, and the detected temperature of the cooling medium is 2. The temperature adjusting device according to claim 1, which is means for driving and controlling the electric pump so that the electric flow is switched to the first flow rate when the temperature falls below a second predetermined temperature.   The temperature adjusting device according to claim 2, wherein the second predetermined temperature is the same temperature as the first predetermined temperature or a temperature lower than the second predetermined temperature.   The temperature control device according to any one of claims 1 to 3, wherein the drive control means is means for stopping the drive of the electric pump when the detected temperature of the cooling medium is lower than a third predetermined temperature.   The temperature control device according to any one of claims 1 to 4, wherein the electric drive system is a system including an electric motor capable of outputting power to drive wheels and a drive circuit for driving the electric motor. The temperature control device according to any one of claims 1 to 5,
The electric vehicle includes an internal combustion engine,
A second circulation path connected to the internal combustion engine and formed as a flow path different from the circulation path;
A pump that is mechanically driven by the rotational force of the output shaft of the internal combustion engine to circulate the cooling medium in the second circulation path;
A temperature control apparatus comprising: a second heat exchanger provided in the second circulation path and performing heat exchange with the cooling medium.

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