JP2006103537A - Cooling system - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a cooling system reduced in the number of parts, simplified in constitution and miniaturized at low cost. <P>SOLUTION: In this system, a first flow passage 33 interposed with a water-cooled engine 51 and a second flow passage 35 interposed with an inverter unit 57, a generator 59 and a driving motor 61 are connected to a radiator 31 in parallel. By the system, an engine cooling system and a hybrid system cooling system are integrated. A switching element of the inverter unit 57 is constituted of a SiC semiconductor device. <P>COPYRIGHT: (C)2006,JPO&NCIPI

Description

  The present invention relates to a cooling system for a hybrid vehicle.

  FIG. 3 is a schematic diagram of a cooling system for a conventional hybrid vehicle. In the conventional cooling system, as shown in FIG. 3, the engine cooling system for cooling the water-cooled engine and the hybrid system cooling system for cooling the hybrid system are separated from each other and provided separately.

  That is, in the engine cooling system, the radiator 3, the cylinder head 5, and the cylinder block 7 are inserted together with the water pump 9 in the flow path 1 for circulating the cooling water, and the water pump 9 circulates the flow path 1 as indicated by the arrow A1. The cylinder head 5 and the cylinder block 7 are cooled by the cooling water. Further, the flow path 11 is branched from the portion of the cylinder head 5 of the flow path 1, and a part of the cooling water that has passed through the cylinder head 5 passes through the flow path 11 and the throttle body 13 and the heater 15 as indicated by an arrow A2. To be supplied. Further, a bypass flow path 17 is provided attached to the flow path 1, and when it is cold, the cylinder head 5 and the cylinder block 7 are cooled by cooling water circulated through the bypass flow path 17 as indicated by an arrow A3. Done. Switching between the flow path 1 and the bypass flow path 17 is performed by a thermostat 19.

  In the hybrid system cooling system, a radiator 22, a drive motor 23, a generator 25, and an inverter unit 27 are inserted together with an electric pump 29 and a reservoir tank 30 in a flow path 21 for circulating cooling water. Then, the drive motor 23, the generator 25, and the inverter unit 27 are cooled by the cooling water circulated through the flow path 21 as indicated by the arrow A4 by the electric pump 29.

  The switching element for power conversion provided in the inverter unit 27 which is a circuit unit for driving the drive motor 23 is configured using a Si semiconductor.

  However, since the engine cooling system and the hybrid system cooling system are provided independently in the above cooling system, the number of parts is increased, the configuration is complicated and large, and the cost is high.

  Accordingly, a first problem to be solved by the present invention is to provide a low-cost cooling system that can reduce the number of parts, simplify the configuration, and reduce the size.

  The second problem to be solved by the present invention is to provide a cooling system capable of integrating the engine cooling system and the hybrid system cooling system while preventing the reliability of the circuit unit from being lowered.

  In order to solve the above-mentioned problems, the invention of claim 1 is a cooling system for a hybrid vehicle, in which a radiator and a water-cooled engine are inserted, and the cooling water flowing out from the radiator is passed through the water-cooled engine to the radiator. And a circuit unit for driving the drive motor, and a second channel for returning the cooling water flowing out from the radiator to the radiator through the circuit unit.

  According to a second aspect of the present invention, in the cooling system according to the first aspect of the invention, the first flow path and the second flow path are inserted into the first flow path and the second flow path. A flow rate adjusting means for adjusting the flow rate of the cooling water flowing through the passage is further provided.

  According to a third aspect of the present invention, in the cooling system according to the first or second aspect of the present invention, the first flow path and the second flow path have integrated portions integrated with each other in a part thereof. The cooling system further includes a pump unit that is inserted in the integrated portion and circulates cooling water through the first flow path and the second flow path.

  According to a fourth aspect of the present invention, in the cooling system according to any one of the first to third aspects, a wide band gap semiconductor is used for the switching element constituting the circuit unit.

  According to a fifth aspect of the present invention, in the cooling system according to the fourth aspect of the present invention, SiC is used as the wide band gap semiconductor.

  According to a sixth aspect of the present invention, in the cooling system according to any one of the first to fifth aspects, the drive motor is inserted in the second flow path and circulates in the second flow path. The drive motor is cooled by the cooling water.

  According to a seventh aspect of the present invention, in the cooling system according to any one of the first to sixth aspects of the present invention, a cooling water circulating through the second flow path is provided with a generator interposed in the second flow path. Thus, the generator is cooled, and the circuit unit also converts the power generated by the generator.

  According to the first aspect of the present invention, the first flow path in which the water-cooled engine is inserted and the second flow path in which the circuit unit is inserted are connected in parallel to the radiator, thereby the engine cooling system. And the hybrid system cooling system are integrated, the number of parts can be reduced, the configuration can be simplified and the size can be reduced, and the cost of the system can be reduced.

  According to the second aspect of the present invention, the flow rate of the cooling water flowing through the first and second flow paths can be adjusted by the flow rate adjusting means according to the operation status of the water-cooled engine, the circuit unit, and the like. It is possible to perform detailed temperature management of the target.

  According to invention of Claim 3, since it is the structure which provides a pump means in the integrated part of a 1st flow path and a 2nd flow path, it is the 1st and 2nd flow path by a single pump means. Cooling water can be circulated in the tank.

  According to the invention described in claim 4, since the wide band gap semiconductor is used for the switching element constituting the circuit unit, the heat resistance of the switching element can be improved, and the cooling water of the water-cooled engine is supplied to the circuit unit. By sharing the cooling, the circuit unit can be stably operated even when the operating temperature of the circuit unit rises. As a result, the engine cooling system and the hybrid system cooling system can be integrated while preventing a reduction in the reliability of the circuit unit.

  According to the invention described in claim 5, since SiC is used for the switching elements constituting the circuit unit, the heat resistance of the switching elements can be improved.

  According to the sixth aspect of the present invention, since the drive motor can be cooled along with the cooling of the circuit unit, it is possible to realize cooling of the drive motor with cooling water while suppressing complication of the configuration. it can.

  According to the seventh aspect of the present invention, since the generator can also be cooled along with the cooling of the circuit unit, it is possible to realize cooling of the generator with the cooling water while suppressing complication of the configuration.

  Further, since the circuit unit is configured to convert the power generated by the generator, there is no need to provide a dedicated circuit unit for converting the power generated by the generator and its cooling means.

  FIG. 1 is a schematic diagram of a cooling system according to an embodiment of the present invention. This cooling system is mounted on a hybrid vehicle and used for cooling the water-cooled engine and the hybrid system. As shown in FIG. 1, the cooling system includes a radiator 31, first and second flow paths 33 and 35, an electric pump (pump means) 37, a flow rate adjusting valve (flow rate adjusting means) 39, A bypass channel 41 and a thermostat 43 are provided.

  The first and second flow paths 33 and 35 are connected to the radiator 31 in parallel with each other. The predetermined sections on both ends of both flow paths 33 and 35 are integrated with each other to form integrated portions 45 and 47, which are connected to the outlet 31a and the inlet 31b of the radiator 31, respectively. ing.

  The electric pump 37 is inserted in either one of the integrated portions 45 or 47 (in the present embodiment, the integrated portion 45), and is connected to the first and second flow paths 33 and 35 as indicated by arrows A5 and A6. Circulate cooling water.

  In the valve 39, the first and second flow paths 33 and 35 are inserted into a branch portion branched from the integrated portion 45, and are controlled by a control section (not shown). Adjust the flow rate of the cooling water flowing out. The control unit controls the valve 39 in accordance with the operation status of the water-cooled engine 51 and the drive motor 61 and adjusts the flow rate of the cooling water flowing through the first and second flow paths 33 and 35. . As a modification, the valve 39 may be inserted in a joining portion where the first and second flow paths 33 and 35 join the integrated portion 47.

  A water-cooled engine 51 is inserted into the first flow path 33 (part other than the integrated portions 45 and 47 of the flow path 33), and when the electric pump 37 is driven, the flow path 33 is interposed. Then, the circulating cooling water is passed through the water cooling engine 51. In the water cooling engine 51, the cooling water is guided in the order of the cylinder block 51a and the cylinder head 51b, and these are cooled.

  The first flow path 33 is provided with a branch path 53. This branch path 53 is branched from the cylinder head 51b portion of the first flow path 33, and the coolant passing through the cylinder head 51b passes through the throttle body 55 and the heater 56 by the branch path 53 as shown by an arrow A7. To be supplied. The cooling water that has passed through the throttle body 55 and the heater 56 is returned to the flow path 33 by the branch path 53.

  In the second channel 35 (portions other than the integrated portions 45 and 47 of the channel 35), an inverter unit 57, a generator 59, and a drive motor 61 are inserted in series in the order closer to the outlet 31a of the radiator 31. When the electric pump 37 is driven, the cooling water circulated through the flow path 35 is passed through the inverter unit 57, the generator 59, and the drive motor 61, and these are cooled. The order of insertion of the objects to be cooled (57, 59, 61) into the flow path 35 is an example, and other orders can be adopted.

  The bypass flow path 41 is a flow path for bypassing the radiator 31 and connects, for example, the integrated portions 45 and 47 at both ends of the first and second flow paths 33 and 35. At the connection part between one end 41a, 41b of the outflow side and inflow side both ends 41a, 41b of the bypass channel 41 and the first and second channels 33, 35 (for example, the integrated portion 47). Is inserted with a thermostat 43 for channel switching. The position of the bypass channel 41 to the channels 33 and 35 is determined such that the electric pump 37 is included in an annular path formed by the bypass channel 41 and the channels 33 and 35. In other words, in this embodiment, the outflow side end 41 a of the bypass flow path 41 is connected to the upstream side portion (the portion between the electric pump 37 and the radiator 31) of the electric pump 37 in the integrated portion 45. In addition, arrow A8 in FIG. 1 has shown the flow direction of the cooling water in the bypass flow path 41. FIG.

  The thermostat 43 distributes the cooling water flowing in from the first and second flow paths 33 and 35 to the radiator 31 side and the bypass flow path 41 side, and the distribution ratio depends on the cooling water temperature. To be determined. For example, as the coolant temperature rises due to engine startup, the flow on the radiator 31 side is changed from the state in which the flow path on the radiator 31 side in the thermostat 43 is fully closed and the flow path on the bypass flow path 41 side is fully opened. When the passage is gradually opened and the passage on the bypass passage 41 side is gradually closed and the cooling water temperature exceeds a predetermined temperature, the passage on the radiator 31 side is fully opened and the bypass passage 41 side is opened. The flow path is fully closed.

  With such a configuration, when the electric pump 37 is driven, cooling water is circulated through the first and second flow paths 33 and 35, and the water cooling engine 51 is cooled by the cooling water circulated through the first flow path 33. Then, the inverter unit 57, the generator 59, and the drive motor 61 are cooled by the cooling water circulated through the second flow path. And the cooling water which passed the 1st and 2nd flow paths 33 and 35 is distributed by the thermostat 43 to the radiator 31 side or the bypass flow path 41 side according to cooling water temperature as mentioned above, thereby The engine 51 is warmed up. The cooling water that has passed through the radiator 13 or the bypass channel 41 is sent again to the first and second channels 33 and 35 and circulated.

  Further, the valve 39 is controlled in accordance with the operating conditions of the water cooling engine 51 and the drive motor 61, and the flow rate of the cooling water circulated through the first and second flow paths 33 and 35 is adjusted. .

  FIG. 2 is a diagram illustrating a circuit configuration of the inverter unit 57. The inverter unit 57 is for performing power conversion for driving the drive motor 61, conversion of power generated by the generator 59, and the like, and includes a converter unit 65 and an inverter unit 67 as shown in FIG. Configured.

  The converter unit 65 boosts the voltage supplied from the battery 69 to drive the drive motor 61 and supplies it to the inverter unit 67, and reduces the regenerative current supplied from the drive motor 61 via the inverter unit 67 to the battery. 69, and a function of stepping down the current generated by the generator 59 and DC-converted by the inverter 67 and supplying the current to the battery 69. For this reason, the converter unit 65 includes a reactor L and switching elements S1 and S2 that step up or step down by chopping the current supplied to the reactor L.

  The inverter unit 67 includes first and second conversion units 67a and 67b. The first converter 67a converts the DC voltage from the battery 69 boosted by the converter 65 into an AC voltage and applies it to the drive motor 61, and converts the regenerative current supplied from the drive motor 61 into a DC converter. And a plurality of switching elements S3 for power conversion. The second conversion unit 67b has a function of converting the current generated by the generator 59 into a direct current and supplying the current to the converter unit 65, and includes a plurality of switching elements S4 for power conversion.

  The switching elements S1 to S4 provided in the converter unit 65 and the inverter unit 67 are elements formed using a wide band gap semiconductor (here, SiC semiconductor) such as SiC (silicon carbide), and are used at a high temperature ( For example, the operation is possible at 250 ° C. or higher). For this reason, for example, even when the temperature of the cooling water of the water-cooled engine 51 is stabilized to about 90 ° C., the switching elements S1 to S4 of the inverter unit 57 are stably operated under the cooling water temperature. Can do.

  As described above, according to the present embodiment, the first flow path 33 in which the water-cooled engine 51 is inserted and the second flow path 35 in which the inverter unit 57, the generator 59 and the drive motor 61 are inserted are the radiators. Since the engine cooling system and the hybrid system cooling system are integrated in parallel, the number of parts can be reduced, the configuration can be simplified and the size can be reduced, and the cost of the system can be reduced. For example, the number of radiators can be reduced.

  Further, the first and second flow paths 33 according to the operating conditions of the water-cooled engine 51 and the drive motor 61 (for example, various operating conditions such as when the engine is running, when the motor is running, and when the engine and the motor are running). , 35 can be adjusted by a valve 39, and fine temperature management of each cooling target is possible.

  In addition, since the electric pump 37 is provided in the integrated portion 45 of the first flow path 33 and the second flow path 35, the first and second flow paths 33 and 35 are operated by the single electric pump 37. The cooling water can be circulated.

  Further, since the switching elements S1 to S4 of the inverter unit 57 are composed of SiC semiconductor devices, the heat resistance of the switching elements S1 to S4 can be improved, and the cooling water of the water-cooled engine 51 is used to cool the inverter unit 57. By sharing, even if the operating temperature of the inverter unit 57 rises, the inverter unit 57 can be stably operated. As a result, the engine cooling system and the hybrid system cooling system can be integrated while preventing the reliability of the inverter unit 57 from decreasing.

  In addition, since the drive motor 61 and the generator 59 can be cooled along with the cooling of the inverter unit 57, it is possible to realize cooling of the drive motor 61 and the generator 59 with cooling water while suppressing complication of the configuration. it can.

  Further, since the inverter unit 57 is configured to convert the power generated by the generator 59, there is no need to provide a dedicated circuit unit for converting the power generated by the generator 59 and its cooling means.

It is a mimetic diagram of a cooling system concerning one embodiment of the present invention. It is a figure which shows the circuit structure of an inverter unit. It is a schematic diagram of the conventional cooling system.

Explanation of symbols

31 Radiator 33 1st flow path 35 2nd flow path 37 Electric pump 39 Valve 41 Bypass flow path 43 Thermostat 45, 47 Integrated part 51 Water-cooled engine 57 Inverter unit 59 Generator 61 Drive motor S1-S4 Switching element

Claims (7)

A cooling system for a hybrid vehicle,
With radiator,
A first flow path in which a water-cooled engine is inserted and cooling water flowing out of the radiator is returned to the radiator through the water-cooled engine;
A second flow path in which a circuit unit for driving the drive motor is inserted, and cooling water flowing out from the radiator is returned to the radiator through the circuit unit;
A cooling system comprising: The cooling system of claim 1, wherein
It further comprises flow rate adjusting means that is inserted in the first flow channel and the second flow channel and adjusts the flow rate of the cooling water flowing through the first flow channel and the second flow channel. Cooling system. The cooling system according to claim 1 or 2,
The first flow path and the second flow path have integrated portions integrated with each other in a part thereof,
The cooling system includes:
The cooling system further comprising a pump unit that is inserted in the integrated portion and circulates cooling water through the first flow path and the second flow path. The cooling system according to any one of claims 1 to 3,
A cooling system characterized in that a wide band gap semiconductor is used for the switching elements constituting the circuit unit. The cooling system according to claim 4.
A cooling system using SiC as the wide band gap semiconductor. The cooling system according to any one of claims 1 to 5,
The cooling system, wherein the drive motor is inserted in the second flow path, and the drive motor is cooled by cooling water circulating in the second flow path. The cooling system according to any one of claims 1 to 6,
A generator is inserted in the second flow path, and the generator is cooled by cooling water circulating in the second flow path.
The cooling system according to claim 1, wherein the circuit unit also performs conversion of electric power generated by the generator.

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