JP5630117B2 - Vehicle cooling device - Google Patents

Description

  The present invention relates to a cooling device that cools an electric heat source such as an internal combustion engine and an inverter mounted on a vehicle.

  In recent years, hybrid vehicles equipped with an internal combustion engine and an electric motor as driving power sources have become widespread. In a hybrid vehicle, the fuel consumption and the exhaust gas amount can be reduced while maintaining a predetermined traveling performance by traveling using an internal combustion engine and an electric motor properly according to the driving state.

  Many hybrid vehicles have an internal combustion engine and an electric motor such as an engine traveling that travels using only the internal combustion engine as a power source, an EV traveling that travels using only the motor as a power source, and an HV traveling that travels using both the internal combustion engine and the motor as a power source. A plurality of driving modes having different operating states are provided, and the driving modes include predetermined mode switching conditions such as a power source map using driving conditions such as vehicle speed (or power source rotation speed) and accelerator operation amount as parameters. It can be switched automatically according to.

  The cooling system of the internal combustion engine mounted on the hybrid vehicle is provided with a cooling water passage (water jacket) in the cylinder block and the cylinder head, as in a general vehicle exclusively using only the internal combustion engine as a power source, and a radiator is provided in the cooling water passage. The installed cooling water circuit is connected. Then, the cooling water in the cooling water circulation path is circulated by the water pump, and the heat generated from the internal combustion engine is radiated by the radiator through the cooling water. The hybrid vehicle has a cooling system for cooling an electric heat source such as an inverter and a boost converter in a PCU (power control unit) in addition to the cooling system for the internal combustion engine (see, for example, Patent Document 1). .)

  FIG. 4 shows an example of a vehicle cooling device mounted on a conventional hybrid vehicle for cooling an electric heat source such as an internal combustion engine (engine) or an inverter.

  As shown in FIG. 4, in the vehicle cooling apparatus of this example, the internal combustion engine cooling system 30 including the cooling water circulation path 31 and the like in which the engine 1 is installed, and the PCU 25 including the inverter 4 and the boost converter 9 and the like. And a cooling system 40 of an electric system heat source constituted by the installed cooling water circulation path 41 and the like. The cooling system 30 of the internal combustion engine and the cooling system 40 of the electric heat source are independent of each other.

  The cooling system 30 of the internal combustion engine includes a first water pump 12, a first radiator 13, a water jacket 14 in a cylinder head of the engine 1, a water jacket 24 in a cylinder block of the engine 1, a heater core 15, a thermostat 16, and the like. Is installed.

  In the internal combustion engine cooling system 30, the cooling water discharged from the first water pump 12 is first supplied to the water jacket 14 in the cylinder head and the water jacket 24 in the cylinder block. Is cooled. The water jackets 14 and 24 are in communication with each other, and the cooling water that has entered the water jacket 24 in the cylinder block flows into the water jacket 14 in the cylinder head through a communication hole provided in a head gasket (not shown). ing. The cooling water that has passed through the water jacket 14 in the cylinder head is split into two at the branching point 17, one being supplied to the first radiator 13 and the other being supplied to the heater core 15. However, when the cooling water temperature is equal to or lower than the predetermined temperature, the thermostat 16 is closed and the supply of the cooling water to the first radiator 13 is stopped. The cooling water dissipates heat when passing through the first radiator 13 or the heater core 15, merges at the junction 18 where the thermostat 16 is installed, and returns to the suction port of the first water pump 12.

  On the other hand, a second water pump 22, a PCU 25, and a second radiator (HV radiator) 23 are installed in the cooling system 40 of the electric heat source.

  In the electric system heat source cooling system 40, the cooling water discharged from the second water pump 22 is supplied to a cooling water passage in the PCU 25, and receives heat generated by the inverter 4, the boost converter 9, and the like in the passage. As a result, these devices 4 and 9 are cooled. Then, the cooling water that has passed through the PCU 25 passes through the second radiator 23 while dissipating heat, and then returns to the suction port of the second water pump 22.

JP 2004-76603 A

  By the way, in a scene where the electric motor is mainly used as a driving power source, such as when the vehicle starts and at a low vehicle speed, the amount of heat generated by the electric heat sources such as the inverter 4 and the boost converter 9 increases. On the other hand, in a scene where the internal combustion engine is mainly used as a driving power source, such as when the vehicle is traveling at a medium or high speed, the amount of heat generated by the electric heat source is reduced. The maximum cooling capacity of the cooling system 40 of the electric heat source is designed based on the case where the load of the electric motor is the highest, such as when the vehicle starts and at a low vehicle speed, and the maximum temperature in the encoper is assumed. For this reason, when the vehicle is traveling at medium to high speeds, the internal combustion engine is mainly used as a power source for traveling, and when the load on the motor is low, surplus capacity is generated in the cooling system 40 of the electric heat source.

  The present invention has been made in view of such circumstances, and an object of the present invention is to provide a vehicle cooling apparatus that can effectively utilize surplus capacity generated in a cooling system of an electric heat source.

  As means for solving the above-described problems, the vehicle cooling device of the present invention is configured as follows.

That is, the vehicle cooling device of the present invention includes a cooling water circulation path, a cooling water circulation apparatus that circulates the cooling water in the cooling water circulation path, and a heat exhaust unit that exhausts the cooling water in the cooling water circulation path. The vehicle is provided with first and second cooling systems that are independent of each other. In the vehicle, the motor is mainly used as a driving power source during low-speed driving, while the internal combustion engine is mainly used during medium-high speed driving. is intended as a power source for running, and the water jacket in the cylinder head of an internal combustion engine, and a water jacket in the cylinder block of an internal combustion engine, it is partitioned into non and out of the cooling water, water in the cylinder head jacket, the first one being installed in the cooling water circulation path of the cooling system has a water jacket of the cylinder block, the driving of the electric motor Electric system heat source that generates heat is disposed in that is characterized by being installed in the cooling water circulation path of the second cooling system has.

  According to the vehicle cooling apparatus having such a configuration, the cylinder block is cooled by the second cooling system when the amount of heat generated by the electric system heat source is relatively small, such as when the vehicle is traveling at a medium to high speed. The surplus capacity of the second cooling system is effectively utilized.

  In the second cooling system, it is desirable that the electric heat source is installed on the upstream side of the cylinder block on the downstream side of the exhaust heat section.

  According to the cooling device for a vehicle having such a configuration, it becomes easy to cool an electric heat source having an allowable temperature lower than that of the cylinder block to a suitable temperature.

  The electric system heat source includes, for example, an inverter.

  According to the vehicle cooling device of the present invention, the cylinder block is cooled by the second cooling system when the amount of heat generated by the electric system heat source is relatively small, such as when the vehicle is traveling at a medium to high speed. The surplus capacity of the cooling system is effectively utilized.

1 is a schematic configuration diagram of a hybrid vehicle equipped with a vehicle cooling device according to an embodiment of the present invention. It is a schematic block diagram which shows the cooling device of the vehicle which concerns on embodiment of this invention. It is a schematic block diagram which shows the cooling device of the vehicle which concerns on other embodiment of this invention. It is a schematic block diagram which shows the conventional vehicle cooling device.

  Hereinafter, embodiments of the present invention will be described with reference to the drawings. FIG. 1 is a schematic configuration diagram of a hybrid vehicle to which a vehicle cooling device according to an embodiment of the present invention is applied.

  FIG. 1 shows a hybrid vehicle having two motors / generators (electric motors) and configured as an FF (front engine / front drive) vehicle. As shown in FIG. 1, the hybrid vehicle includes an engine 1, a first motor / generator MG1, a second motor / generator MG2, a power distribution mechanism 2, a speed reducer 3, an inverter 4, an HV battery 5, driving wheels 7, and a boost converter. 9, ECU (Electronic Control Unit) 100 and the like.

-Engine-
The engine 1 is an internal combustion engine that outputs power by burning fuel such as a gasoline engine or a diesel engine. The engine 1 is configured such that the ECU 100 controls the operation state such as the throttle opening (intake amount), the fuel injection amount, and the ignition timing. Further, the rotational speed (engine rotational speed) of the crankshaft 8 that is the output shaft of the engine 1 is detected by an engine rotational speed sensor (not shown). The engine 1 is driven and controlled by the ECU 100.

-Motor generator-
Motor generators MG1 and MG2 are AC synchronous motors, and function as an electric motor (traveling power source) and also as a generator. Motor generators MG1 and MG2 are connected to HV battery 5 via inverter 4 and boost converter 9, and driving power for motor generators MG1 and MG2 is from HV battery (running power battery) 5 to boost converter 9, It is supplied via the inverter 4. The inverter 4 is controlled by the ECU 100, and the regeneration or power running (assist) of the motor / generators MG1 and MG2 is set by the control of the inverter 4. The regenerative power at that time is charged to the HV battery 5 via the inverter 4. The inverter 4 and the boost converter 9 are installed in a unitized PCU (power control unit) 25.

-Power distribution mechanism-
In the power distribution mechanism 2, a planetary gear mechanism (planetary gear) is used to distribute the power of the engine 1 to both the drive wheels 7 and the first motor / generator MG1. By controlling the rotational speed of the first motor / generator MG1, the power distribution mechanism 2 also functions as a continuously variable transmission. For example, the rotational power of the engine 1 is input to a planetary carrier (not shown), which is transmitted to the first motor / generator MG1 by a sun gear (not shown), and the second motor / generator by a ring gear (not shown). It is transmitted to MG2 and the output shaft (drive wheel 7 side).

  In a hybrid vehicle equipped with a hybrid system as shown in FIG. 1, when the engine 1 is inefficient at the time of starting or running at a low speed, the hybrid vehicle travels (EV) only by the second motor / generator MG2. Run). Further, during normal traveling, for example, the power distribution mechanism 2 divides the power of the engine 1 into two paths, and on the one hand, the drive wheels 7 are directly driven, and on the other hand, the first motor / generator MG1 is driven to generate power. At this time, the second motor / generator MG2 is driven by the generated electric power to assist driving of the driving wheels 7. Further, when driving at high speed, the electric power from the HV battery 5 is further supplied to the second motor / generator MG2 to increase the output of the second motor / generator MG2 to add driving force to the drive wheels 7. Is also possible.

  On the other hand, at the time of deceleration, the second motor / generator MG2 driven by the drive wheels 7 functions as a generator to perform regenerative power generation, and the recovered power is stored in the HV battery 5. When the amount of charge of the HV battery 5 is reduced and charging is particularly necessary, the output of the engine 1 is increased to increase the amount of power generated by the first motor / generator MG1 and the amount of charge to the HV battery 5 is increased. . Of course, control is performed to increase the drive amount of the engine 1 as necessary even during low-speed traveling. The case where the above-mentioned charging is particularly necessary is, for example, the case where the HV battery 5 needs to be charged as described above, the case where an auxiliary machine such as an air conditioner is driven, or the temperature of the cooling water of the engine 1 is reduced to a predetermined temperature. For example.

  The ECU 100 obtains the required output torque of the engine 1 and the output torque of the motor generators MG1 and MG2 based on output signals from a vehicle speed sensor, an accelerator opening sensor, a shift position sensor and the like (not shown), and Generators MG1 and MG2 are controlled.

-Vehicle cooling system-
Hereinafter, a vehicle cooling device mounted on the vehicle for cooling an electric heat source such as the engine 1 or an inverter will be described with reference to FIG.

  As shown in FIG. 2, the vehicle cooling device includes a first cooling system 10 including a first cooling water circulation path 11 and the like indicated by a solid line, and a second cooling water circulation path 21 and the like indicated by a broken line. The second cooling system 20 is provided.

  The first cooling system 10 and the second cooling system 20 are independent of each other. That is, the first cooling system 10 and the second cooling system 20 are not in communication with each other so that cooling water does not enter and exit between the first cooling system 10 and the second cooling system 20. It has become.

  A first water pump 12, a first radiator 13, a water jacket 14 in the cylinder head of the engine 1, and heating of the passenger compartment are provided on the first cooling water circulation path 11 of the first cooling system 10. A heater core 15, a thermostat 16 and the like are provided.

  The first water pump 12 is a cooling water circulation device provided to circulate the cooling water in the first cooling water circulation path 11. The first radiator 13 is a heat radiating unit that radiates heat (exhaust heat) of the cooling water in the first cooling water circulation path 11.

  The water jacket 14 in the cylinder head and the water jacket 24 in the cylinder block, which will be described later, are partitioned by a head gasket (not shown) interposed between the cylinder head and the cylinder block so that the cooling water cannot enter and exit. ing. That is, the head gasket is not provided with a communication hole for communicating both the water jackets 14, 24.

  In the first cooling system 10 illustrated in FIG. 2, the cooling water discharged from the first water pump 12 is first supplied to the water jacket 14 in the cylinder head to cool the cylinder head. When the cooling water passes through the water jacket 14 of the cylinder head, it is divided into two branches at the branching point 17, one being supplied to the first radiator 13 and the other being supplied to the heater core 15. However, when the coolant temperature is equal to or lower than the predetermined temperature, the thermostat 16 is closed and the supply of the coolant to the first radiator 13 is stopped.

  The cooling water that has dissipated heat while passing through the radiator 13 and the heater core 15 joins at a joining point 18 where the thermostat 16 is installed, and returns to the suction port of the first water pump 12.

  On the other hand, a second water pump 22, a PCU (power control unit) 25, a water jacket 24 in a cylinder block of the engine 1, and a second radiator are disposed on the second cooling water circulation path 21 of the second cooling system 20. (HV radiator) 23 etc. are installed.

  The second water pump 22 is a cooling water circulation device provided to circulate the cooling water in the second cooling water circulation path 21. The second radiator 23 is a heat radiating unit that radiates heat (exhaust heat) of the cooling water in the second cooling water circulation path 21. The PCU 25 is a unit obtained by unitizing the inverter 4, the boost converter 9, and the like.

  In the second cooling system 20 illustrated in FIG. 2, the cooling water discharged from the second water pump 22 is first supplied to the cooling water passage in the PCU 25, and in the passage, the inverter 4, the boost converter 9, etc. Receiving the heat generated by it, these devices are cooled. The cooling water that has passed through the PCU 25 is supplied to the water jacket 24 in the cylinder block to cool the cylinder block.

  The cooling water that has passed through the water jacket 24 in the cylinder block passes through the second radiator while dissipating heat, and then returns to the suction port of the second water pump 22.

  On the second cooling water circulation path 21, the inverter 4 and the like in the PCU 25 having different heat generation amounts and the water jacket 24 in the cylinder block are installed. The heat generation amount of the cylinder block is the heat generation amount of the cylinder head. Since it is less than half of the amount and not so large, it is possible to cool both the inverter 4 and the like in the PCU 25 and the cylinder block to an appropriate temperature. However, since the allowable temperature of the inverter 4 etc. in the PCU 25 is lower than that of the cylinder block, the PCU 25 is installed upstream of the cylinder block on the downstream side of the second radiator 23 as described above. Is desirable.

-Other embodiments-
Hereinafter, a modification of the second cooling system will be described with reference to FIG. In addition, the same code | symbol is attached | subjected about the thing similar to the structure demonstrated in above-mentioned embodiment, and description is abbreviate | omitted.

  The second cooling system 20 </ b> A according to the modified example is also independent of the first cooling system 10. The second water pump 22, PCU 25, the water jacket 24 in the cylinder block, the second radiator (HV radiator) 23, and the like are also installed on the second cooling water circulation path 21A of the second cooling system 20A. Has been.

  In the second cooling system 20A illustrated in FIG. 3, the cooling water discharged from the second water pump 22 is first diverted at the branch point 26, and one is supplied to the cooling water passage in the PCU 25. In the passage, the inverter 4 and the boost converter 9 receive heat and cool these devices. Then, the other divided coolant is supplied to the water jacket 24 in the cylinder block to cool the cylinder block. The cooling water that has passed through the cooling water passage in the PCU 25 and the water jacket 24 in the cylinder block joins at the joining point 27, then passes through the second radiator while dissipating heat, and then the suction port of the second water pump 22. To reflux.

  According to the vehicle cooling device described above, the following effects are recognized as compared with the vehicle cooling device according to the conventional example described with reference to FIG.

  That is, when the internal combustion engine is mainly used as a driving power source when the vehicle is traveling at a medium or high speed and the load on the motor is relatively small, the amount of heat generated by the inverter 4 and the boost converter 9 is relatively small. Since the cylinder block is cooled by the second cooling system 20, 20A (electric system heat source cooling system), the surplus capacity of the second cooling system 20, 20A (electric system heat source cooling system) is effectively utilized. .

  In addition, since the cylinder block is excluded from the cooling target of the first cooling system 10, the remaining capacity of the cooling capacity is generated in the first cooling system 10. For this reason, it becomes possible to increase the cooling capacity of the cylinder head. Or, conversely, the radiator (the first radiator 13) can be downsized.

  Further, in the second cooling systems 20 and 20A, the temperature of the cooling water can be set lower than that of the first cooling system 10, so that the cylinder can be used even if the circulating flow rate of the cooling water in the cylinder block is reduced. The block can be sufficiently cooled. As a result, for example, the size of the second water pump 22 can be reduced.

  Further, in the second cooling systems 20 and 20A, the temperature of the cooling water can be set lower than that in the first cooling system 10, and accordingly, the groove depth of the water jacket 24 in the cylinder block is made shallower. By doing so, the cooling effect of the upper part of the cylinder bore can be locally enhanced. This suppresses the upper part of the cylinder bore that is likely to be relatively high in temperature from being deformed into a trumpet shape due to thermal strain (expanding the diameter toward the deck surface). Although it seems that the cooling effect of the middle or lower part of the cylinder bore is deteriorated by reducing the groove depth of the water jacket 24, the cooling effect of the middle part or the lower part is reduced by lowering the cooling water temperature. It is possible to maintain.

  The present invention is applicable to a cooling device that cools an electric heat source such as an internal combustion engine and an inverter mounted on a vehicle.

1 engine (internal combustion engine)
4 Inverter (electric heat source)
9 Boost converter (electric heat source)
DESCRIPTION OF SYMBOLS 10 1st cooling system 11 1st cooling water circulation path 12 1st water pump (cooling water circulation apparatus)
13 First radiator (heat exhaust section)
14 Water jacket in cylinder head (cylinder head)
20 Second cooling system 21 Second cooling water circulation path 22 Second water pump (cooling water circulation device)
23 Second radiator (heat exhaust section)
24 Water jacket in cylinder block (cylinder block)
25 PCU

Claims (3)

The first and second independent from each other, each having a cooling water circulation path, a cooling water circulation device for circulating the cooling water in the cooling water circulation path, and a heat exhaust unit for exhausting the cooling water in the cooling water circulation path. In a vehicle cooling device provided with a cooling system of
In the vehicle, the electric motor is mainly used as a driving power source during low-speed driving, while the internal combustion engine is mainly used as a driving power source during medium-high speed driving.
The water jacket in the cylinder head of the internal combustion engine and the water jacket in the cylinder block of the internal combustion engine are partitioned so that the cooling water cannot enter and exit,
While the water jacket in the cylinder head is installed on the cooling water circulation path of the first cooling system,
Water jacket of the cylinder block, the cooling of the vehicle, characterized in that the electrical system heat source which generates heat when driving the electric motor is installed is installed, the cooling water circulation path of the second cooling system has apparatus. The vehicle cooling device according to claim 1,
In the second cooling system, the electric system heat source is installed on the upstream side of the cylinder block on the downstream side of the exhaust heat unit. The vehicle cooling device according to claim 1 or 2,
The electric system heat source includes an inverter, and includes a cooling device for a vehicle.

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