JPH11200858A - Hybrid electric vehicle cooling system - Google Patents

Abstract

(57) [Problem] To provide a cooling device for a hybrid electric vehicle that enables two radiators to control the refrigerant temperature of three different cooling systems and improves the volumetric efficiency when mounted on a vehicle. An engine cooling system having a high target cooling water temperature,
A motor cooling system with a medium target cooling water temperature, a battery with a low target cooling water temperature, and a weak electric cooling system are provided, and a phase difference between the target control temperature of the motor cooling system and the target control temperature of the battery and the weak electric cooling system is provided. A heat storage device 116 having a changing temperature is provided, and the refrigerant of the three cooling systems is configured to exchange heat in the heat storage device 116.
The refrigerant of the engine cooling system or the refrigerant of the heat storage device is selectively introduced.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a cooling device for a hybrid electric vehicle, and more particularly, to a hybrid electric vehicle having a plurality of cooling systems each having a different target control temperature. A technique for achieving and minimizing the occupied volume of a heat exchanger.

[0002]

2. Description of the Related Art A conventional cooling device for a hybrid electric vehicle has a structure as shown in FIG. 8 as disclosed in, for example, JP-A-7-253020. This prior art includes a driving electric motor 1 for driving wheels, a battery 2 for supplying electric power to the electric motor 1,
Third cooling that connects an engine 4 that drives a generator 3 to supply power to the battery 2, at least a first cooling water circulation passage R1 that cools the electric motor 1, and a second cooling water circulation passage R2 that cools the engine 4. A cooling means having a water circulation passage R3 is provided, and as a heat exchange means, a first radiator 5a for the electric motor 1 connected via the first cooling water circulation passage R1 and a heat exchange means connected via a second cooling water circulation passage R2. And a second radiator 5b.

[0003]

However, in such a conventional cooling device for a hybrid electric vehicle, a radiator is required for each of an engine cooling system and a motor cooling system. A radiator (third radiator) for the cooling system of the weak electric system or the battery system, which is not considered, is also required. Here, in the above-mentioned prior art, there is also proposed a method of cooling the motor cooling system and the engine cooling system by the same radiator. In this case, the cooling water temperature is equal between the engine and the motor. It is difficult to control Also, the third
Including the radiator described above, three heat exchangers are required, and there is a problem in that the mountability on a vehicle is impaired.

The present invention has been made in view of such a conventional problem, and enables two radiators to control the temperature of a refrigerant in three different cooling systems, thereby improving the volumetric efficiency when mounted on a vehicle. An object of the present invention is to provide a cooling device for a hybrid electric vehicle that can be improved.

[0005]

SUMMARY OF THE INVENTION The present invention solves the above-mentioned problems by providing a mode in which the vehicle runs on an internal combustion engine.
In a hybrid electric vehicle having a mode in which a battery is driven by driving a motor, an engine cooling system having a high target cooling water temperature, a motor cooling system having a medium target cooling water temperature, a battery having a low target cooling water temperature, and cooling of a weak electric system. A heat storage device having a phase change temperature between a target control temperature of the motor cooling system and a target control temperature of the battery and the weak electric system cooling system, wherein the three cooling system refrigerants are used in the heat storage device. In addition to performing heat exchange, it is possible to selectively introduce a refrigerant of the engine cooling system or a refrigerant of the heat storage device into the motor cooling system.

[0006]

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS Embodiments of a cooling device for a hybrid electric vehicle according to the present invention will be described below in detail with reference to the accompanying drawings. FIG. 1 is a diagram showing an embodiment of a cooling device for a hybrid electric vehicle according to the present invention.

First, the structure will be described with reference to FIG. 1. An engine 101 is mounted by an internal combustion engine and outputs to an axle. The engine 101 has an engine cooling water pipe 1
02 and the first radiator 103 are connected. Water is passed through the cooling water pipe 102 by a mechanical water pump 104 driven by the engine 101. Since an engine using an internal combustion engine has a high operating temperature, the target control temperature (T _H ) of the engine cooling system refrigerant is set to a relatively low temperature.

On the other hand, the electric motor 107 is used for output to an axle and for energy regeneration when the vehicle is decelerated. For output to the axle, the engine 101 and the electric motor 107 are selectively used. For example, the motor running at low vehicle speed and the engine running at middle to high vehicle speed. Therefore, the frequency at which both the engine 101 and the electric motor 107 operate is low. The electric motor 107 is connected to a cooling water pipe 108 for the electric motor. The inlet side is connected to the outlet tank 105 of the first radiator 103 via the electric water pump 109 for the motor cooling system and the three-way switching valve 110. Connected to the first radiator 1
03 is connected to the inlet tank 106. In general, the higher the temperature of an electric motor, the lower the efficiency. Therefore, the target refrigerant temperature (T _M ) of the motor cooling system is set lower than the engine cooling system refrigerant temperature.

The control unit 1 of the electric motor 107
11 and a battery 112 for supplying or charging electric power to the electric motor 107, a cooling water pipe 113 for the weak electric system is connected, and an electric water pump 114 for the weak electric cooling system and the second radiator 115 are connected. Have been. Since this path includes an electric circuit,
The target is control at the lowest target temperature (T _L ) as compared with the cooling system of the system.

[0010] Further, a heat storage device 116 utilizing latent heat due to a phase change is provided. This heat storage device 1
Details of 16 are shown in FIG. A heat storage agent 117 utilizing latent heat or the like is sealed in the center. The heat storage agent 117 is set to have a phase change temperature between the target cooling water temperature (T _M ) of the electric motor 107 system and the target cooling water temperature (T _L ) of the weak electric cooling system. Around the heat storage agent 117, a water jacket 1 communicating with a cooling system of the electric motor 107 is provided.
18 and a water jacket 119 communicating with the cooling system of the weak electric system. Each jacket 118, 11
9 and the heat storage agent 117 are thermally connected by heat pipes 120 and 121 having different operating temperatures. The operating temperature depends on the heat pipe 1 connected to the electric motor cooling system.
At 20, the temperature is higher than the heat storage agent operating temperature, and at the heat pipe 121 connected to the weak electric system cooling system, the temperature is set to be approximately the same as the target control temperature of the weak electric system cooling system.

The three-way switching valve 110 includes a path from the output tank 105 of the first radiator 103 to the electric motor 107 via the motor cooling system electric water pump 109, and a heat storage device 116 to the motor cooling system electric water pump. It functions to switch the path to the electric motor 107 via the power supply 109.

The electric water pumps 109 and 114 and the three-way switching valve 110 are connected to the control unit 12.
2 is controlled. In the control unit 122, control is performed by inputting signals of the refrigerant temperature sensor 123 in the outlet tank 105 of the first radiator 103 and the heat storage agent temperature sensor 124 in the heat storage device 116.

Next, the operation of this embodiment will be described. First, the necessity of dividing the refrigerant temperature into a plurality will be described.
The calorific value of the engine Q _H, the target refrigerant temperature T _H, the heat value of the electric motor Q _H, the target refrigerant temperature T _M, the heating value of the light electric system Q _L, the target refrigerant temperature is T _L. Here, as described above, a _{T H> T M> T L} . Performance required for the radiator, the cooling air temperature is T _a, respectively _{K H = Q H / (T} H -T a) K M = Q M / (T M -T a) K L = Q L / to become (T _L -T _a).

Here, if one cooling system is used and the whole is to be cooled by one radiator, the target refrigerant temperature must be adjusted to the lowest temperature (T _L ).
The performance of heat-sensitive components such as weak electrical systems will be reduced. Accordingly, the performance required of the _{radiator, K = (Q H + Q} M + Q L) / (T L -T a) = Q H / (T L -T a) + Q M / (T L -T a) + Q _L
To become (T _L -T _a). Here, T _H> T _M> because it is _{T L, K = Q H /} (T L -T a) + Q M / (T L -T a) + Q
_{L (T L -T a)>} Q H / (T H -T a) + Q M / (T
_M− T _a ) + Q _L (T _L −T _a ) = K _H + K _M + K _{L In} other words, it is possible to individually have a cooling system corresponding to the refrigerant temperature corresponding to each target control temperature and to control each of them optimally. This leads to minimizing the required volume of the heat dissipation system. In this sense, three radiators, an engine cooling system radiator, an electric motor cooling system radiator, and a weak electric system radiator, are required.

However, in the vehicle targeted by the present invention, since the driving of the axle by the engine and the driving of the axle by the electric motor are switched, a radiator for cooling the engine and a radiator for the electric motor are used. However, it can be said that there is no condition that requires large heat radiation at the same time. This indicates that the engine cooling system radiator and the electric motor cooling system radiator may be shared.

However, as described above, since the target control temperature of the engine cooling system is different from the target control temperature of the electric motor cooling system, the target control temperature of the electric motor cooling system is changed from the state controlled to the target control temperature of the engine cooling system. It takes time to reduce the temperature to the control temperature, and there is a risk that the electric motor may overheat. For example, when the electric motor drive mode is entered immediately after high-load running with the engine, the cooling water temperature may not immediately decrease, and the motor performance may not be sufficiently brought out.

Therefore, in the present invention, the first radiator 10
3 is used as a radiator for an engine cooling system when the engine 101 is running, and is used as a radiator for an electric motor cooling system when the electric motor 107 is operated. Hereinafter, the description will be made in conjunction with the flowchart shown in FIG.

FIG. 3 shows the flow of water when the engine 101 is operating (FIG. 7: step S1, Yes) and the electric motor 107 is not operating (FIG. 7: step S2, No).
Shown in

The mechanical water pump 104 rotates to allow the refrigerant to flow through the cooling water pipe 102 for the engine and the first radiator 103 to release the heat absorbed by the engine 101 to the atmosphere. Here, the first radiator 103
Of course, the heat radiation performance of the engine 101 is controlled by, for example, a cooling fan (not shown) so as to reach the target refrigerant temperature of the engine 101. During that time, the three-way switching valve 110 opens the heat storage device 116 and the electric motor-driven water pump 109 for the motor cooling system, thereby opening the first radiator 1.
03 and the electric motor cooling system are separated. But,
Since the electric motor 107 is not operating, the motor cooling system electric water pump 109 is not operating.

Here, the heat storage agent 117 in the heat storage device 116
However, if the temperature is equal to or lower than a predetermined temperature (for example, phase change temperature −10 ° C.) (FIG. 7: Step S3, Yes), the electric water pump 114 for the weak electric cooling system does not operate (FIG. 7: Step S4).

On the other hand, if the heat storage agent 117 is at or above a predetermined temperature (for example, a phase change temperature + 10 ° C.), the electric motor 10
7, the electric water pump 114 for the cooling system for the weak electric system is operated irrespective of the operation / non-operation of the step 7 (FIG. 7: Step S).
5). This indicates that the second radiator 115 acts as a radiator of the heat storage device 116, and the heat storage agent 117 is always kept in a state capable of absorbing latent heat.

Next, when the engine 101 is operating (FIG. 7: step S1, Yes) and the electric motor 107 is also operating (FIG. 7: step S2, Yes), the outlet tank 105 of the first radiator 103 is operated. The control differs depending on the refrigerant temperature at.

First, a temperature sensor 1 for detecting the temperature of the refrigerant
When the signal of 23 is lower than the target control temperature of the electric motor cooling system (when the engine operation is a light load or the time after starting is short) (FIG. 7: step S6, Yes), As shown in FIG.

The three-way switching valve 110 "opens" the space between the outlet tank 105 of the first radiator 103 and the electric water pump 109 for the electric motor cooling system, and cools the first radiator 103 to cool the engine 101 and the electric motor 107. Use as a container. In this case, the control temperature of the refrigerant is controlled to the target temperature of the electric motor 107.

On the other hand, the electric water pump 114 for the cooling system for the weak electric system is also operated, and the control unit 11 of the electric motor 107 is operated.
1 and the battery 112 are cooled by the second radiator 115. The control temperature of the refrigerant here is controlled to the target temperature of the weak electric cooling system.

Next, when the signal of the temperature sensor 123 is higher than the target control temperature of the electric motor cooling system (when the engine operation is under a heavy load or the time after starting is long) (FIG. 7: step S6). No.) is shown in FIG.

The three-way switching valve 110 includes a heat storage device 116
And the electric water pump 109 for the electric motor cooling system is opened, and the first radiator 103 is connected to the engine 101.
, And the electric motor 107 is cooled by the latent heat of the heat storage device 116.

Also, the water pump 11 for the weak electric cooling system
4 is also operating, and the control unit 1 of the electric motor 107
11 and the battery 112 are cooled by the second radiator 115. In this case, since the heat of the heat storage agent 117 is also radiated by the second radiator 115, the second radiator 115 also functions as a radiator of the electric motor 107.

Here, when the refrigerant temperature of the weak electric system is higher than the target temperature, the heat of the heat storage 117 cannot be recovered. Therefore, in the present invention, heat exchange between the heat storage agent 117 and the weak electric cooling system is performed by the heat pipe 121, and the operating temperature of the heat pipe 121 is set to about the target temperature of the weak electric cooling system. When the refrigerant of the system cooling system is higher than the target temperature, the working medium in the heat pipe 121 cannot be completely condensed, so that the heat exchange performance is reduced.

Next, the engine 101 does not operate (FIG. 7:
(Step S1, No), the water flow state when the electric motor 107 is operating (FIG. 7: Step S9, Yes)
As shown in FIG.

Since the mechanical water pump 104 does not operate, the electric water pump 109 for the electric motor cooling system is operated to allow water to flow through the first radiator 103. That is, the three-way switching valve 110 is connected to the outlet tank 105 and the electric water pump 1 for the electric motor cooling system.
09 is set to “open”. The first radiator 103 is dedicated to cooling the electric motor 107.

Finally, the engine 101 is connected to the electric motor 10
7 does not operate (FIG. 7: Step S1, No, Step S9, No), there is no need for cooling, so the electric water pump 109 for the electric motor cooling system is not operated, but the heat storage agent 117 of the heat storage device 116 is not operated. In order to keep the temperature below the phase change temperature, the temperature of the temperature sensor 124
Only when the temperature is equal to or higher than the phase change temperature of 7, the electric water pump 114 for the weak electric cooling system is operated.

[0033]

As described above in detail, according to the present invention, a hybrid electric vehicle having a configuration in which a mode in which the vehicle runs on an internal combustion engine and a mode in which the vehicle runs by driving a motor with a battery is provided. An engine cooling system having a high target cooling water temperature, a motor cooling system having a medium target cooling water temperature, a battery having a low target cooling water temperature, and a weak electric system cooling system. A heat storage device having a phase change temperature between the target control temperature of the system cooling system and the three cooling system refrigerants exchanging heat in the heat storage device; Engine cooling system
While selectively introducing the refrigerant of the heat storage device, in the heat storage device, heat exchange between the battery and the weak electric cooling system uses a heat transfer element having an operating temperature range such as a heat pipe. Since the heat exchange performance is degraded at a certain temperature or higher,
The three radiators can control the refrigerant temperatures of the three cooling systems differently, thereby improving the volumetric efficiency when mounted on a vehicle. Further, since unnecessary resistors are not placed in the ventilation system of the cooling air, the effect that the cooling performance of the engine room is secured is obtained.

[Brief description of the drawings]

FIG. 1 is a diagram showing an embodiment of a cooling device for a hybrid electric vehicle according to the present invention.

FIG. 2 is a detailed view of a heat storage device.

FIG. 3 is an operation explanatory diagram of the present embodiment.

FIG. 4 is an operation explanatory diagram of the present embodiment.

FIG. 5 is an operation explanatory view of the present embodiment.

FIG. 6 is an operation explanatory diagram of the present embodiment.

FIG. 7 is a flowchart for explaining the operation of the present embodiment.

FIG. 8 is a diagram illustrating a cooling device for a hybrid electric vehicle according to the related art.

[Explanation of symbols]

 101 engine 102 cooling water pipe for engine 103 first radiator 104 mechanical water pump 105 outlet tank 106 inlet tank 107 electric motor 108 cooling water pipe for electric motor 109 electric water pump for electric motor cooling system 110 three-way switching valve 111 electric motor 107 Control unit 112 battery 113 weak electric system cooling water pipe 114 weak electric system cooling system electric water pump 115 second radiator 116 heat storage device 117 heat storage agent 118, 119 water jacket 120, 121 heat pipe 122 control unit 123 refrigerant temperature sensor 124 Thermal storage agent temperature sensor

Continued on the front page (51) Int.Cl. ⁶ Identification code FI F01P 7/04 F01P 7/04 A

Claims (2)

[Claims] 1. A mode for running on an internal combustion engine,
In a hybrid electric vehicle that has a mode in which a motor is driven by a battery and runs, an engine cooling system with a high target cooling water temperature, a motor cooling system with a medium target cooling water temperature, a battery with low target cooling water temperature, and cooling of the weak electric system A heat storage device having a phase change temperature between a target control temperature of the motor cooling system and a target control temperature of the battery and the weak electric system cooling system, wherein the three cooling system refrigerants are used in the heat storage device. A cooling device for a hybrid electric vehicle, wherein the cooling device is configured to exchange heat and selectively introduces a refrigerant of the engine cooling system or a refrigerant of the heat storage device to a motor cooling system. 2. The cooling device for a hybrid electric vehicle according to claim 1, wherein in the heat storage device, heat exchange between the battery and the weak electric cooling system has an operating temperature range such as a heat pipe. A cooling device for a hybrid electric vehicle, wherein the heat exchange performance is reduced at a certain temperature or higher.