JP2002276364A - Cooling system for hybrid electric vehicle - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a cooling system for hybrid electric vehicle capable of being simply constituted at a low cost by integrating an internal combustion engine to the cooling system of an electric motor. SOLUTION: An electric motor cooling water passage 180 branched and combined so as to be parallel to the downstream water passage 171 of a main radiator 130 is provided in an engine cooling water passage 180, and a sub- radiator 140 and the electric motor 120 are arranged in the passage 180 successively to the cooling water flowing direction. A flow regulating valve 210 for regulating the flow distribution of the cooling water passing through the downstream water passage 171 and the passage 180 and the electric pump 220 for circulating the cooling water to the engine cooling water passage 170 are provided in the branch part 171a of the downstream water passage 171, and the opening of the flow regulating valve 210 and the discharge flow rate from the electric pump 220 are controlled by a control means 230 according to the load state of an engine 110 and the electric motor 120.

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.

[0002]

2. Description of the Related Art As a conventional cooling device for a hybrid electric vehicle, as disclosed in Japanese Patent Application Laid-Open No. 10-252664, cooling devices for cooling an internal combustion engine and a motor as power units are provided independently of each other. In the case where one cooling device exceeds the cooling capacity, another cooling device is additionally used.

More specifically, as shown in FIG. 5, an internal combustion engine cooling device 101 having an engine cooling water passage 170, a main radiator 130, and a first pump 220a, an electric motor cooling water passage 180, a sub radiator 140, a second pump 22
0b are provided, respectively.
Further, a plurality of communication water passages 173 for communicating the engine cooling water passage 170 with the motor cooling water passage 180 and a plurality of water flow control valves 211 for opening and closing the water passages 170 and 173 are provided. In addition, a water temperature control ECU 230a that controls opening and closing of the plurality of water flow control valves 211 based on detection signals of the water temperature sensors 241 and 242 and the accelerator sensor 243 is provided.

Normally, the internal combustion engine 110 and the electric motor 120 are cooled by respective cooling devices 101 and 102.
When the cooling capacity required for cooling the cooling water exceeds the cooling capacity of each cooling device 101 or 102, the water temperature control ECU 230a controls the plurality of water flow control valves 2
11 is controlled to open and close, and the other cooling device 102 or 101 is additionally used by the communication water channel 173.

As a result, the cooling capacity can be increased, and each of the cooling devices 101, 102 can be prepared in case of rarely generated high heat.
It is no longer necessary to increase the cooling capacity of the internal combustion engine 110 and the cooling devices 101, 1 of the electric motor 120.
02, the cooling capacity required is reduced, and as a result, the cost and weight of each of the cooling devices 101 and 102 can be reduced.

[0006]

However, usually, the cooling water passages 170 and 180 and the pumps 220a and 220a and the pumps 220a and 220a are used to cool the internal combustion engine 110 and the electric motor 120, respectively.
20b, and a plurality of communication water passages 173 and a water flow control valve 211 are provided in preparation for high heat generation, so that the overall configuration is complicated and expensive.

An object of the present invention is to provide a simple and inexpensive cooling device for a hybrid electric vehicle by integrating a cooling device for an internal combustion engine and an electric motor in view of the above problems.

[0008]

The present invention employs the following technical means to achieve the above object.

According to the first aspect of the present invention, the internal combustion engine (1
10) and a first electric radiator (130) for cooling a cooling water flowing through an internal combustion engine (110) and a motor (120), which is applied to a hybrid electric vehicle including a motor and a motor (120) as a power unit. A cooling device for a hybrid electric vehicle having a second radiator (140) for cooling cooling water;
0) and a cooling water passage (170) in which cooling water circulates between the first radiator (130) and a downstream water passage (171) downstream of the first radiator (130). Motor cooling water channel (1
80), and the second motor cooling water passage (180)
A radiator (140) and a motor (120) are provided. And the branch part (171) of the downstream waterway (171)
a) a flow control valve (210) for adjusting the flow distribution of the cooling water flowing through the downstream water passage (171) and the electric motor cooling water passage (180); and circulating the cooling water through the internal combustion engine cooling water passage (170). An electric pump (220) and a control means (230) for controlling the operation of the flow regulating valve (210) and the electric pump (220) are provided.
0), the internal combustion engine (110) and the electric motor (12)
The valve opening degree of the flow control valve (210) and the discharge flow rate of the electric pump (220) are controlled according to the load state of 0).

Accordingly, the cooling device for the internal combustion engine (110) and the electric motor (120) can be branched from the internal combustion engine cooling water channel (170) by providing the flow control valve (210), even if they are not provided separately. A motor cooling water channel (180) can be formed, and one electric pump (22
0) makes it possible to circulate the cooling water in both cooling water passages (170, 180), and it can be used as a simple and inexpensive cooling device.

Further, by adjusting the flow distribution to the downstream water passage (171) and the motor cooling water passage (180) by the flow control valve (210), and by varying the discharge flow by the electric pump (220), Radiator (130, 14
Since the cooling water required for 0) can be circulated, cooling according to the load state of the internal combustion engine (110) and the electric motor (120) can be performed.

According to the second aspect of the present invention, the second radiator (140) and the electric motor (120) are arranged so that the second radiator (140) and the electric motor (120) are arranged in the direction of the cooling water flow in the electric motor cooling water passage (180). Are arranged in this order.

Thus, the motor (120) can be cooled by the cooling water sequentially cooled by the first radiator (130) and the second radiator (140), so that the motor (120) is normally used for the internal combustion engine (110). Is more effective at cooling at a lower temperature (the electric motor is around 70 ° C. while the internal combustion engine is around 100 ° C.).

Further, according to the third aspect of the present invention, the second radiator (140) is provided with the first radiator (130).
If the motor (120) is arranged at a position not affected by the heat radiation, the temperature difference between the cooling air and the cooling water can be increased, and the temperature drop of the cooling water can be increased. Can be cooled.

Further, in the invention according to claim 4, the first radiator (130) is provided in the cooling water passage (170) of the internal combustion engine.
A bypass water passage (172) is provided to bypass the water passage, and the downstream side of the bypass water passage (172) is connected to the flow control valve (210). The flow control valve (210) is connected to the downstream water passage (171) and the electric motor. In addition to the cooling channel (180)
The first radiator (130) and the bypass waterway (17)
It is characterized in that the flow rate distribution of the cooling water flowing through 2) is also adjusted.

Thus, the normal bypass waterway (172)
The function of the thermostat provided in the
0), a more inexpensive cooling device can be obtained.

The reference numerals in the parentheses of the above means indicate the correspondence with the concrete means described in the embodiment described later.

[0018]

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS (First Embodiment) FIGS. 1 and 2 show a first embodiment of the present invention. The hybrid electric vehicle according to the present invention has an internal combustion engine (hereinafter, engine) 110 and an electric motor 120 as power units, and the engine 110 and the electric motor 120 are selectively used according to a traveling mode.

The electric motor 120 includes an inverter that converts DC power from a battery into AC power, an electric motor that drives a drive shaft of a vehicle with the AC power, and a generator that generates AC power by obtaining the power of the engine 110. And a converter for converting the generated AC power into DC power and charging the battery. The inverter and the converter have a semiconductor element for switching and controlling the generated large current at a high speed. The semiconductor element and the electric motor are main heat sources of the electric motor 120.

A cooling device 100 for a hybrid electric vehicle
Is an engine cooling device 101 for cooling the engine 110.
And a motor cooling device 102 for cooling the motor 120. The cooling water temperature of the engine 110 is controlled at around 100 ° C., and the cooling water temperature of the motor 120 is controlled at around 70 ° C.

The engine cooling device 101 includes an engine 11
The engine 11 has a main radiator 130 as a first radiator for cooling the cooling water flowing through the inside of the engine 11.
An engine cooling water passage 170 through which cooling water circulates between the main radiator 130 and the main radiator 130 is provided.

The engine cooling water passage 170 has a bypass water passage 172 that bypasses the main radiator 130.
Is provided, and the downstream side of the bypass water passage 172 is connected to a flow control valve 210 described later.

On the other hand, the motor cooling device 102
And a sub-radiator 140 as a second radiator for cooling the cooling water 20. The sub-radiator 140 is branched in the engine cooling water passage 170 together with the electric motor 120 so as to be parallel to a downstream water passage 171 downstream of the main radiator 130. , Are arranged in the motor cooling water passage 180 that joins the two. Here, the sub radiator 140 is supplied with high temperature (100) from the engine 110 via the main radiator 130 or the bypass water passage 172 as described later.
(Around 70 ° C.), the temperature needs to be greatly reduced to the water temperature (around 70 ° C.) required for cooling the electric motor 120, and the basic cooling capacity is increased.
The flow rate of the circulating cooling water is set to be small. The sub-radiator 140 and the motor 120 are arranged in this order in the flow direction of the cooling water indicated by the arrow in the drawing.

At the junction 172a between the bypass channel 172 and the downstream channel 171 and at the branch 171a between the downstream channel 171 and the motor cooling channel 180, the flow control valve 21 is provided.
0 is provided. As shown in FIG. 2, the flow control valve 210 includes a motor 210a driven by a control unit 230 described later, and a rotary first valve 210b and a second valve 210c rotated by the motor 210a. As described in detail below, the main radiator 130, the bypass waterway 172, the downstream waterway 1
71, the flow rate distribution of the cooling water flowing through the motor cooling water passage 180 is adjusted.

The first valve 210b is connected to the main radiator 13
0 (hereinafter referred to as radiator flow rate Vr) and the flow rate flowing through bypass water passage 172 (hereinafter referred to as bypass flow rate Vr).
b) is varied. When the main radiator 130 is rotated from the fully closed state to the fully open state, the bypass water passage 172 side is changed from the fully open state to the fully closed state, and the radiator flow rate Vr is sequentially increased, and conversely, the bypass flow rate Vb is sequentially reduced. I have.

The second valve 210c is connected to the downstream water passage 17
1 (hereinafter referred to as the downstream flow rate Vr1) and the flow rate flowing through the motor cooling water passage 180 (hereinafter referred to as the motor flow rate Vr1).
e) is varied. Motor cooling channel 1
When the 80 side is turned from the fully closed state to the fully open state, the downstream water passage 171 side is changed from the fully open state to the fully closed state, and the motor flow rate Ve increases sequentially, and conversely, the downstream flow rate Vr1 decreases. I have.

An electric pump 220 for circulating cooling water through the engine cooling water passage 170 is provided downstream of a junction 180 a where the downstream water passage 171 of the main radiator 130 and the electric motor cooling water passage 180 join. An internal motor and an impeller are rotationally driven by a control means 230 to be described later, so that the discharge flow rate of the cooling water, that is, the circulation flow rate is varied. When the second valve 210c of the flow control valve 210 opens the motor cooling water passage 180 side, the cooling water is also circulated to the motor cooling water passage 180 by the electric pump 220. As a matter of course, the circulation flow rate increases in accordance with the number of rotations of the motor.

Assuming that the discharge flow rate of the electric pump 220 is Vp, the relationship between the above flow rates Vr, Vb, Vr1, and Ve is as follows: Vp = Vr + Vb = Vr1 + Ve.

An electronic control unit (hereinafter referred to as E
The CU (230) controls the operation of the flow control valve 210 and the electric pump 220 according to the load state of the engine 110 and the electric motor 120.

Here, the load state of the engine 110 is determined based on the engine water temperature, the engine speed, and the engine intake pressure, and the water temperature sensor 241, the speed sensor 244, and the pressure sensor 245 detect these. A signal is input to the ECU 230.

The load state of the motor 120 is as follows.
Here, the determination is made based on the rotation speed of the electric motor, the battery voltage, and the current values of the semiconductor elements that control the inverter and the converter. The rotation speed sensor 246, the voltage detection unit 247, and the current detection unit 248 detect these. The detection signal is input to the ECU 230.

In addition, a detection signal from a vehicle speed sensor 249 for detecting the traveling speed of the vehicle is also input to the ECU 230. As a matter of course, the load on the engine 110 and the electric motor 120 is higher as the above detection signal values are larger.

Upon receiving the various detection signals, the ECU 23
A value of 0 changes the valve opening of the flow control valve 210 and the rotation speed of the electric pump 220.

More specifically, the first valve 210b in the flow control valve 210 opens the bypass water passage 172 side fully when the engine water temperature is lower than a predetermined temperature, such as in winter, or when the load on the engine 110 is low. It is rotated so that the 130 side is fully closed. Then, when the engine water temperature becomes equal to or higher than a predetermined temperature or as the load of the engine 110 increases, the bypass water passage 172 side is closed,
The main radiator 130 is rotated so as to be sequentially opened.

The second valve 210 in the flow control valve 210
When the engine 110 is mainly operated, c is rotated so that the downstream water passage 171 side is fully opened and the motor cooling water passage 180 side is completely closed. When the motor 120 is mainly operated, the motor cooling water passage 180 is fully opened and the downstream water passage 171 is fully closed. Further, when the engine 110 and the electric motor 120 are operated in combination, the rotation is performed so that both the downstream water passage 171 and the electric motor cooling water passage 180 are opened at a predetermined opening degree.

With respect to the electric pump 220, the engine 1
When the load of the motor 10 and the motor 120 is low, the rotation is controlled to the low rotation side, and as the load increases, the rotation is controlled to the high rotation side.

The arrangement of the main radiator 130 and the sub radiator 140 is such that the sub radiator 140 and the sub radiator 140 are not affected by the air whose temperature has increased due to heat exchange.
0 is on the upstream side of the main radiator 130. Incidentally, a condenser 150 constituting a refrigeration cycle (not shown) is interposed between the sub radiator 140 and the main radiator 130 to cool the refrigerant flowing inside.

Further, the heater core 16 constituting the heating device
0 is the engine cooling channel 170, the motor cooling channel 1
The heater core water passage 190 is provided separately from the heater core water passage 190. The downstream side of the heater core 160 is connected to the upstream side of the electric pump 220, and the electric pump 220 circulates cooling water in the heater core water passage 190 to heat air passing through the heater core 160. .

Next, the operation based on the above configuration will be described.

The hybrid electric vehicle has an engine 11
The operation of each of the motor 0 and the motor 120 is optimized by utilizing the point where the operation efficiency is optimal, and the operations of the two are used separately or in combination. The operation for specific running conditions will be described below.

When starting the engine, especially when the engine water temperature is low, such as during winter,
Cooling water flowing out of the engine 110 in order to promote warming of the
Circulated back to engine 110 via 72,
The temperature is raised to a predetermined water temperature in a short time without being cooled by the radiator 130. (During this time, the electric motor 120 is stopped.) Thereafter, the engine 110 is stopped. In this case, the discharge flow rate of the electric pump 220 is controlled to be small. (5 L / min level in this embodiment) At the time of starting and at the time of light load The electric motor of the electric motor 120 capable of generating a large operating torque mainly operates (the engine 110 stops).
Mode, and the cooling water flowing out of the engine 110 is
After flowing through the main radiator 130 or the bypass water passage 172, it is guided to the motor cooling water passage 180 side by the second valve 210c of the flow control valve 210, further cooled by the sub radiator 140, and the motor 120 is cooled by the cooling water. After that, the cooling water returns to the downstream channel 171 of the radiator 130 at the junction 180a, and the engine 110
Flows into. At this time, since the load on the motor 120 itself is low, the discharge flow rate of the electric pump 220 is controlled to be small.
(In this embodiment, the level is 5 L / min.) At the time of normal running, the engine 110 mainly operates with the engine 110 capable of running with low torque and optimizing fuel consumption efficiency (the electric motor 12).
0 is stopped) mode, the cooling water flowing out of the engine 110 is cooled by the main radiator 130, and then flows through the downstream water passage 171 by the second valve 210c of the flow control valve 210, flows into the engine 110, The engine 110 is cooled. At this time, since the load on the engine 110 itself is low, the discharge flow rate of the electric pump 220 is controlled to an intermediate amount. (60 L / min level in the present embodiment) At the time of full open load In the case of high-speed running or uphill running, the engine 11
In this mode, the motor 120 is used in combination with the operation mainly performed by the main radiator 130, and the cooling water flowing out of the engine 110 is cooled by the main radiator 130.
A part of the cooling water is guided to the motor cooling water passage 180 side by the second valve 210c of 10, and further cooled by the sub-radiator 140, and the motor 120 is cooled by the cooling water. Thereafter, the cooling water joins the cooling water flowing through the downstream water passage 171 at the junction 180 a and flows into the engine 110. At this time, since the loads on the engine 110 and the electric motor 120 are high, the discharge flow rate of the electric pump 220 is largely controlled.

In the present embodiment, the total discharge flow rate of the electric pump 220 is set at a level of 65 L / min.
The flow rate distribution at the second valve 210c of the flow rate adjustment valve 210 is 60 L / min for the downstream water passage 171 and 5 L / min for the motor cooling water passage 180, respectively.

At the time of deceleration and braking In this case, the driving force on the drive shaft side of the vehicle is applied to the motor 120, and the generator in the motor 120 is operated (the engine 110 is stopped). Performs the same operation as.

As described above, in the present embodiment, the motor cooling water passage 180 branched from the engine cooling water passage 170 by providing the flow control valve 210, even if it is not provided separately, as the cooling device for the engine 110 and the electric motor 120. Can be formed, and the cooling water in both cooling water passages 170 and 180 can be circulated by one electric pump 220, which can be used as a simple and inexpensive cooling device.

The radiators 130 and 140 are required for the radiators 130 and 140 by adjusting the flow distribution to the downstream water passage 171 and the motor cooling water passage 180 by the flow control valve 210 and by changing the discharge flow by the electric pump 220. Since the cooling water can flow, cooling according to the load state of the engine 110 and the electric motor 120 can be performed.

In particular, at the time of starting or light load, in the case of the traveling mode mainly by the motor 120, or when the engine 11
In the case of the driving mode using both the motor 0 and the electric motor 120,
Since the cooling water can be cooled using both the main radiator 130 and the sub radiator 140, a sufficient cooling effect can be obtained.

Further, since the sub radiator 140 and the motor 120 are arranged in the motor cooling water passage 180 in this order from the upstream side, the motor 120 can be cooled by the cooling water sequentially cooled by the main radiator 130 and the sub radiator 140, and the engine The motor 120 is controlled at a lower temperature than the motor 110 (the internal combustion engine is around 100 ° C. and the motor is around 70 ° C.), so that it can be cooled effectively.

Further, since the sub radiator 140 is disposed upstream of the cooling air flow of the main radiator 130 so as not to be affected by the heat radiation of the main radiator 130, the temperature difference between the cooling air and the cooling water is reduced. The cooling water temperature can be increased, and the motor 1
20 can be cooled.

FIG. 3 shows the outlet water temperature of the engine 110 and the electric motor 1 at the time of full load in the prior art and this embodiment.
The results of a simulation study of the inlet water temperature of No. 20 are shown. Here, the physique of the sub radiator 140 of the present embodiment is approximately three times the entire area of the conventional technology,
Circulation flow rate is 5 L / mi compared to 8 L / min of the prior art.
n. Further, the circulation flow rate to the main radiator 130 is 65 L / m compared to 60 L / min of the conventional technology.
in.

At the motor inlet water temperature, as described above, the temperature drop increases due to the reduction in the cooling capacity of the sub-radiator 140, and at the engine outlet water temperature,
The cooling of both the main radiator 130 and the sub radiator 140 has the effect of reducing the water temperature.

The flow control valve 210 has a first valve 210 for controlling the radiator flow Vr and the bypass flow Vb.
Since b is provided, the function of the conventional thermostat can be integrated into the flow control valve 210, and a more inexpensive cooling device can be obtained.

(Other Embodiments) As shown in FIG.
As the flow control valve 210, the first valve 210b is abolished, and only the second valve 210c is provided.
A well-known thermostat 200 may be provided at a junction 172a between the second water passage 171 and the downstream water passage 171. Thus, the structure of the flow control valve 210 can be simplified.

[Brief description of the drawings]

FIG. 1 is a schematic diagram showing an overall configuration of a first embodiment of the present invention.

FIG. 2 is a schematic view showing the structure of a flow control valve.

FIG. 3 is a result of a simulation comparison between an engine outlet water temperature and an electric motor inlet water temperature at full load in the conventional art and the present embodiment.

FIG. 4 is a schematic diagram showing the overall configuration of another embodiment.

FIG. 5 is a schematic diagram showing the entire configuration of a conventional technique.

[Explanation of symbols]

 Reference Signs List 110 engine (internal combustion engine) 120 electric motor 130 main radiator (first radiator) 140 sub radiator (second radiator) 170 engine cooling water passage (internal combustion engine cooling water passage) 171 downstream water passage 171a branch portion 172 bypass water passage 180 motor cooling water passage 210 flow rate Regulating valve 220 Electric pump 230 Electronic control unit (control means)

Claims (4)

[Claims] An internal combustion engine (110) and an electric motor (12)
0) as a power unit, comprising: a first radiator (130) for cooling cooling water flowing through the internal combustion engine (110); and a second radiator (130) cooling cooling water flowing through the electric motor (120). 2
A cooling device for a hybrid electric vehicle having a radiator (140), wherein the internal combustion engine (110) and the first radiator (1)
30), the cooling water circulating through the internal combustion engine (17)
0), and branches and joins in parallel with the downstream water channel (171) downstream of the first radiator (130), and the second radiator (140) and the electric motor (120) Motor cooling water channel to be provided (180)
And a flow control valve () provided at a branch (171a) of the downstream water channel (171) and for adjusting a flow distribution of cooling water flowing through the downstream water channel (171) and the motor cooling water channel (180). 210), an electric pump (220) for circulating cooling water through the internal combustion engine cooling water passage (170), the flow regulating valve (210) and the electric pump (22).
Control means (230) for controlling the operation of the internal combustion engine (110) and the electric motor (120). ) And the electric pump (2)
20) A cooling device for a hybrid electric vehicle, wherein the discharge flow rate is controlled. 2. The motor cooling water passage (180), wherein the second radiator (140) and the electric motor (120) are connected to each other.
Of the second radiator (14
0) The cooling device for a hybrid electric vehicle according to claim 1, wherein the cooling device is arranged in the order of the electric motor (120). 3. The radiator according to claim 1, wherein the second radiator is disposed at a position not affected by heat radiation of the first radiator. A cooling device for a hybrid electric vehicle according to any one of the above. 4. The internal combustion engine cooling water passage (170) has a bypass water passage (172) that bypasses the first radiator (130), and a downstream side of the bypass water passage (172) is connected to the flow control valve (210). ), And the flow control valve (210) is connected to the downstream water passage (17).
1) In addition to the motor cooling water channel (180), the first radiator (130) and the bypass water channel (17)
The cooling device for a hybrid electric vehicle according to any one of claims 1 to 3, wherein the flow rate distribution of the cooling water flowing through (2) is also adjusted.