Waste heat utilization system

Abstract

To provide a waste heat utilization system capable of efficiently utilizing waste heat.SOLUTION: The waste heat utilization system 1 includes an oil flow path 10 that supplies oil to a travel motor 8A, a heating unit 14 that heats air used to heat a passenger compartment, and heat pipes 16 that are provided across the oil flow path 10 and the heating unit 14 and are formed of a heat transfer material, and the heat pipes 16 recover heat that is generated by the travel motor 8A from the oil on one end side and dissipate the heat to the heating unit 14 on the other end side.SELECTED DRAWING: Figure 2

Description

[Technical Field]

[0001] The present invention relates to a waste heat utilization system that utilizes waste heat in a vehicle. [Background technology]

[0002] Conventionally, electric vehicles without internal combustion engines have been used. In such electric vehicles, when heating is required during cold weather, a heat pump is used to heat the vehicle interior. However, when the outside temperature is even lower, the heat pump may not be able to operate, and temperature control is performed using an electric heater or the like. Temperature control using such an electric heater consumes a lot of power, which can cause a deterioration in power consumption. Therefore, technology for heating the vehicle interior while suppressing a deterioration in power consumption has been studied (for example, Patent Document 1).

[0003] Patent Document 1 describes a heating system for an automobile. This heating system includes a cooling path that cools the motor that drives the automobile, an air path through which heating air flows, a heat pump type heating path that exchanges heat with the air in the air path, and a heat pipe that connects a first heat exchanger disposed on the cooling path with a second heat exchanger that exchanges heat with a refrigerant flowing through the heat pump type heating path. This allows waste heat from the motor to be recovered in the cooling path, and the recovered heat is used for heating, thereby improving electricity efficiency. [Prior art documents] [Patent documents]

[0004] [Patent Document 1] Japanese Patent Application Laid-Open No. 2014-91507 Summary of the Invention [Problem to be solved by the invention]

[0005] In the heating system described in Patent Document 1, heat is first exchanged between the heat of the oil circulating in the motor and the heat pipe, then between the heat pipe and the external heat exchanger, and finally between the external heat exchanger and the refrigerant. Because multiple heat exchanges are performed in this way, loss is significant. Therefore, the heating system described in Patent Document 1 has room for improvement in terms of efficiently utilizing the waste heat from the vehicle.

[0006] Therefore, a waste heat utilization system that can efficiently utilize waste heat is required. [Means for solving the problem]

[0007] The waste heat utilization system according to the present invention is characterized by comprising an oil flow path that supplies oil to the vehicle's traction motor, a heating unit that heats the air used to heat the passenger compartment, and a heat pipe made of a heat-conductive material that is provided between the oil flow path and the heating unit, with one end of the heat pipe recovering heat from the oil generated by the traction motor and the other end radiating the heat to the heating unit.

[0008] With this characteristic configuration, a heat pipe is provided between the oil flow path through which oil heated by the motor flows and the heating section that heats the air used for heating, allowing the air used for heating to be heated using the waste heat of the motor. This allows the heating of the vehicle cabin to be started quickly even when the vehicle is cold. Furthermore, since oil has a lower specific heat capacity than water, it has a high temperature rise rate, allowing the air used for heating to be heated more quickly than when water is used for heating. Furthermore, by utilizing the waste heat of the motor, it is possible to improve power consumption. In this way, this waste heat utilization system makes it possible to efficiently utilize the waste heat of the motor. [Brief explanation of the drawings]

[0009] [Figure 1] FIG. [Figure 2] FIG. 1 is a diagram illustrating a configuration of a waste heat utilization system. [Figure 3] 3 is a flowchart showing the process of the waste heat utilization system. [Figure 4] FIG. 10 is a diagram showing the configuration of a waste heat utilization system according to another embodiment. DETAILED DESCRIPTION OF THE INVENTION

[0010] The waste heat utilization system according to the present invention is configured to efficiently utilize waste heat in a vehicle and quickly heat the vehicle's interior even when it is cold. The waste heat utilization system 1 according to this embodiment will be described below. However, the waste heat utilization system 1 is not limited to the following embodiment and various modifications are possible without departing from the spirit and scope of the invention.

[0011] 1 is a side view of a vehicle 2 equipped with a waste heat utilization system 1 according to this embodiment. In this embodiment, the front side of the vehicle 2 in the traveling direction is indicated by "F," and the rear side of the vehicle 2 in the traveling direction is indicated by "B." Furthermore, the upper side of the vehicle 2 in the vertical direction is indicated by "U," and the lower side of the vehicle 2 in the vertical direction is indicated by "D."

[0012] As shown in FIG. 1 , a battery 3 that stores power used for propelling the vehicle 2 is mounted on the bottom 2A of the vehicle 2. The vehicle 2 is equipped with a vehicle drive device 4. The vehicle drive device 4 is housed in a motor room 7 on the front side F in the direction of travel, which is separated from the passenger compartment 5 by a partition wall 6A of the dashboard 6. The vehicle drive device 4 has a traveling drive unit 8 and a power supply module 9. The traveling drive unit 8 is provided in the lower part of the vehicle drive device 4, and the power supply module 9 is provided in the upper part of the vehicle drive device 4.

[0013] The traveling drive unit 8 has a motor 8A (corresponding to a "travel motor") that outputs power that enables the vehicle 2 to travel, and a gear mechanism 8B. The motor 8A and the gear mechanism 8B are arranged side by side along the vehicle width direction. The motor 8A is driven by a power supply module 9. The motor 8A and the gear mechanism 8B are connected via a motor shaft, and the rotation of the motor 8A is input to the gear mechanism 8B via the motor shaft. The gear mechanism 8B reduces the rotation of the motor 8A and outputs it from the gear shaft. The vehicle 2 travels using the output of the motor 8A via the gear mechanism 8B.

[0014] The power supply module 9 includes an OBC (On Board Charger) board 9A, a motor drive board 9B, and a control board 9C that controls the OBC board 9A and the motor drive board 9B. An inverter and a converter are mounted on the OBC board 9A. The inverter receives AC power consisting of AC voltage from a commercial power source and converts the AC power into DC power including DC voltage. The converter receives DC power generated by the inverter and boosts the DC voltage that constitutes the DC power supplied from the inverter to a DC voltage with a voltage value required to charge the battery 3. Therefore, the power supply module 9 can supply power to the battery 3 of the vehicle 2.

[0015] A drive inverter that controls the drive current that drives the motor 8A is mounted on the motor drive board 9B. A control unit that controls the inverter and converter is mounted on the control board 9C. Therefore, the power supply module 9 can supply power to the motor 8A. Note that this configuration of the power supply module 9 is merely an example and can be modified as appropriate.

[0016] Fig. 2 is a diagram schematically illustrating the configuration of the waste heat utilization system 1. As shown in Fig. 2, the waste heat utilization system 1 includes an oil flow path 10, an oil cooler 12, a heating unit 14, a heat pipe 16, a heater core 35, and a flap 37 (switching mechanism).

[0017] The oil flow path 10 supplies oil to the motor 8A of the vehicle 2. The oil is discharged to the motor 8A from the vertically upper side U of the motor 8A. This cools and lubricates the motor 8A. The oil discharged to the motor 8A is stored in the oil pan OP below. In this embodiment, the oil flow path 10 corresponds to an oil path through which the oil is sent from the oil cooler 12, discharged to the motor 8A, stored in the oil pan OP, and flows before returning to the oil cooler 12. Therefore, the oil circulates through the oil flow path 10.

[0018] The oil stored in the oil pan OP is cooled by an oil cooler 12 attached to the oil pan OP. The oil cooler 12 is provided on the oil flow path 10. Coolant is introduced into the oil cooler 12, and heat exchange occurs between the oil and the coolant. This cools the oil. After exchanging heat with the oil, the coolant is discharged from the oil cooler 12.

[0019] The vehicle 2 is provided with an air conditioning unit 30, which includes a blower 31, a cooler core 33, a heating section 14, a heater core 35, and a flap 37. The blower 31 draws in outside air and sends the drawn outside air to the cooler core 33.

[0020] The cooler core 33 exchanges heat between the air and the coolant to cool or heat the vehicle interior 5. The air is outside air drawn in by the blower 31. The cooler core 33 is configured to allow a relatively low-temperature coolant to flow through it. The cooler core 33 has the function of condensing and removing moisture from moisture-containing air, converting it into dry air. Therefore, the cooler core 33 functions as an adsorption section that adsorbs moisture. The cooler core 33 is provided between the blower 31 and the heater core 35. Therefore, the outside air sent from the blower 31 is sent to the heater core 35 via the cooler core 33.

[0021] The heater core 35 exchanges heat between air and coolant to heat or cool the vehicle interior 5. The air is air sent from the cooler core 33. A coolant with a relatively high temperature is introduced into the heater core 35. Therefore, in the heater core 35, heat exchange occurs between the air sent from the cooler core 33 and the coolant with a relatively high temperature, and the air after the heat exchange is introduced into the vehicle interior 5. Specifically, the air heated in the heater core 35 is introduced into the vehicle interior 5 as hot air through the duct 6B. This makes it possible to heat the vehicle interior 5.

[0022] When heating the passenger compartment 5, the air introduced by the blower 31 is heated by heat exchange with the coolant introduced into the heater core 35, which has a relatively high temperature. However, when the vehicle is cold, the coolant is not sufficiently warmed and the air cannot be heated, and as a result, the passenger compartment 5 cannot be heated. Therefore, the waste heat utilization system 1 is provided with a heating unit 14 between the cooler core 33 and the heater core 35, and is configured so that the heating unit 14 uses waste heat in the vehicle 2 to heat the air used to heat the passenger compartment 5. The air used to heat the passenger compartment 5 is air introduced into the air conditioning unit 30 by the blower 31. This air is configured to be introduced into the heating unit 14.

[0023] A heat pipe 16 made of a heat-conductive material is provided between the oil flow path 10 and the heating unit 14. A heat-conductive material is a material with high thermal conductivity, such as copper or aluminum. The heat pipe 16 is made of such a material and is provided to connect the oil flow path 10 and the heating unit 14.

[0024] The heat pipe 16 is configured to collect heat generated by the motor 8A from the oil at one end and radiate the heat to the heating unit 14 at the other end. The heat generated by the motor 8A is heat generated by the passage of current through the motor 8A. In this embodiment, the heat of the oil after cooling the motor 8A is utilized. Therefore, the heat pipe 16 collects heat from the oil from the oil cooler 12 at one end. The heating unit 14 is configured, for example, using a heat sink with multiple fins to increase the surface area, and the other end of the heat pipe 16 is connected to the heat sink. This allows the heat pipe 16 to radiate heat to the heating unit 14. That is, air from the blower 31 is introduced into the heat sink, and heat is exchanged between this air and the heat sink, thereby radiating heat from the heat pipe 16 to the heating unit 14. Therefore, the heat pipe 16 collects heat from the oil circulating from the oil cooler 12 at one end and radiates heat to the heat sink constituting the heating unit 14 at the other end.

[0025] In this embodiment, a heat exchanger 20 is provided in the oil flow path 10 between the oil cooler 12 and the oil discharged to the motor 8A. One end of the heat pipe 16 is connected to the heat exchanger 20, and the oil flow path 10 flows through the heat exchanger 20. This allows heat exchange between the oil flowing through the oil flow path 10 and the heat pipe 16, and the one end of the heat pipe 16 is heated by the oil. Therefore, it is possible to recover heat generated by the motor 8A through heat exchange with the oil flowing out of the oil cooler 12.

[0026] The air conditioning unit 30 is provided with a flap 37 (switching mechanism) that switches between a first state and a second state depending on the temperature of the heater core 35 and the temperature of the oil. The first state is a state in which air is introduced into the heating unit 14 (the state shown by the solid line in FIG. 2). Therefore, in the first state, the air introduced by the blower 31 is heated by the heating unit 14. The second state is a state in which air is blocked from entering the heating unit 14 (the state shown by the two-dot chain line in FIG. 2). Therefore, in the second state, the air introduced by the blower 31 is not heated by the heating unit 14.

[0027] As a result, when the engine is cold, even if the heater core 35 is not yet warmed up at start-up, the flap 37 can be set to the first state, which causes the motor 8A to drive and heat the oil, and the heat from this oil can be used to heat the air. Once the heater core 35 has warmed up, the flap 37 can be set to the second state, which allows the heater core 35 to heat the air instead of the heating unit 14. For this reason, it is preferable that the flap 37 be switched between the first state and the second state depending on the temperature of the heater core 35 and the temperature of the oil.

[0028] Specifically, the first state may be set when the temperature of the heater core 35 is lower than the temperature of the heating section 14, and the second state may be set when the temperature of the heater core 35 is higher than the temperature of the heating section 14. Of course, depending on the temperatures of the heater core 35 and the oil, the flap 37 may introduce a portion of the air introduced by the blower 31 into the heating section 14 and the remainder directly into the heater core 35. Also, when cooling the interior of the passenger compartment 5, the second state may be set so that the air cooled by the cooler core 33 is not heated in the heating section 14.

[0029] Next, the processing of the waste heat utilization system 1 will be described with reference to the flowchart of Fig. 3. First, the supply of electricity to the motor 8A begins (step #1). As the electricity is supplied to the motor 8A, the supply of oil to the motor 8A begins (step #2).

[0030] When there is a request to heat the passenger compartment 5 (Step #3: Yes), and the oil temperature is higher than the temperature of the heater core 35 (Step #4: Yes), the air conditioning unit 30 is switched to the first state by the flap 37 (Step #5). In this case, the passenger compartment 5 is heated using the heat of the oil.

[0031] On the other hand, in step #4, if the oil temperature is not higher than the temperature of the heater core 35 (step #4: No), the air conditioning unit 30 is switched to the second state by the flap 37 (step #6). In this case, the heat of the heater core 35 is used to heat the passenger compartment 5. When the heating of the passenger compartment 5 in step #5 or #6 is terminated (step #7: Yes) and the driving of the motor 8A is terminated (step #8: Yes), the waste heat utilization system 1 terminates the processing.

[0032] In step #7, if heating of the passenger compartment 5 is not to be terminated, the process returns to step #4 and continues. In step #8, if operation is not to be terminated, the process returns to step #3 and continues. Furthermore, in step #3, if there is no request for heating of the passenger compartment 5 (step #3: No), the process continues from step #8. The waste heat utilization system 1 performs processing based on this flowchart. This makes it possible to use waste heat in the vehicle 2 to heat the air used for heating.

[0033] Other Embodiments Next, other embodiments of the waste heat utilization system 1 will be described.

[0034] In the above embodiment, the vehicle drive device 4 is described as being housed in the motor room 7 on the front side F in the traveling direction, which is separated from the passenger compartment 5 by the partition wall 6A of the dashboard 6. However, the vehicle drive device 4 may also be disposed on the rear side B in the traveling direction of the partition wall 6A.

[0035] In the above embodiment, an example was given in which the heat exchanger 20 was provided in the oil flow path 10, but the heat exchanger 20 may be provided at a position between when the oil is supplied to the motor 8A and when it accumulates in the oil pan OP. Alternatively, a configuration may be adopted in which the heat exchanger 20 is not used. In this case, for example, a through-hole that connects the oil flow path 10 to the outside is formed in the housing that accommodates the traveling drive unit 8, and a heat pipe 16 is inserted into the through-hole with one end positioned inside the oil flow path 10. In this manner, heat can also be recovered from the oil flowing in the oil flow path 10 at one end of the heat pipe 16.

[0036] In the above embodiment, heat exchange is described as occurring between the oil and the heat pipes 16 in the heat exchanger 20. However, as shown in Fig. 4, the waste heat utilization system 1 may be provided with a switching valve 50 that switches between a state in which the oil from the oil cooler 12 is circulated to the motor 8A after heat exchange and a state in which the oil is circulated to the motor 8A without heat exchange. In this case, in the second state described above, the oil from the oil cooler 12 may be configured to bypass the heat exchanger 20 and be supplied directly to the motor 8A.

[0037] [Summary of the above embodiment] The waste heat utilization system 1 described above will now be outlined.

[0038] (1) The waste heat utilization system 1 includes an oil flow path 10 that supplies oil to a motor 8A (travel motor) of a vehicle 2, a heating section 14 that heats the air used to heat the passenger compartment 5, and a heat pipe 16 made of a heat-conductive material that is provided between the oil flow path 10 and the heating section 14. The heat pipe 16 recovers heat from the oil generated by the travel motor at one end and dissipates the heat to the heating section 14 at the other end.

[0039] According to this configuration, a heat pipe 16 is provided between the oil flow path 10, through which oil heated by the motor 8A flows, and the heating section 14, which heats the air used for heating, so that the air used for heating can be heated using the waste heat of the motor 8A. This allows heating of the passenger compartment 5 to be started quickly even when the vehicle is cold. Furthermore, since oil has a lower specific heat capacity than water, it has a high temperature rise rate, and the air used for heating can be heated more quickly than when water is used for heating. Furthermore, by utilizing the waste heat of the motor 8A, it is possible to improve power consumption. In this way, the waste heat utilization system 1 allows for efficient utilization of the waste heat of the motor 8A.

[0040] (2) In the waste heat utilization system 1 described in (1), it is preferable to provide an oil cooler 12 that is provided on the oil flow path 10 and cools the oil, and to recover the heat generated by the motor 8A by heat exchange with the oil flowing out from the oil cooler 12.

[0041] According to this configuration, heat exchange with the oil supplied to the motor 8A can be performed, thereby reducing the temperature of the oil used to cool the motor 8A. Therefore, it is possible to simultaneously heat the passenger compartment 5 and cool the motor 8A.

[0042] (3) In the waste heat utilization system 1 described in (1) or (2), the heating section 14 is preferably provided in the air conditioning unit 30, the air conditioning unit 30 has a heater core 35, and the air conditioning unit 30 is preferably provided with a flap 37 (switching mechanism) that switches between a first state in which air is introduced into the heating section 14 and a second state in which air is blocked from entering the heating section 14, depending on the temperature of the heater core 35 and the temperature of the oil.

[0043] According to this configuration, when the oil temperature is higher than the heater core 35, the flap 37 is set to the first state and the air is heated by the heating unit 14, thereby heating the interior of the passenger compartment 5. On the other hand, when the oil temperature is lower than the heater core 35, the flap 37 is set to the second state and the air is heated by the heater core 35, thereby heating the interior of the passenger compartment 5.

[0044] (4) In the waste heat utilization system 1 described in (3), it is preferable to provide a switching valve 50 that switches between a state in which oil from the oil cooler 12 flows to the motor 8A after heat exchange and a state in which oil flows to the motor 8A without heat exchange.

[0045] With this configuration, for example, when the outside temperature is high, the heat pipe 16 is heated by the warm air introduced into the waste heat utilization system 1, and it is possible to prevent the oil from being heated by this heat pipe 16. Therefore, when the outside temperature is high, it is possible to suppress an increase in the temperature of the oil supplied to the motor 8A. [Industrial Applicability]

[0046] The technology disclosed herein can be used in a waste heat utilization system that utilizes waste heat in a vehicle. [Explanation of symbols]

[0047] 1: Waste heat utilization system, 2: Vehicle, 5: Vehicle compartment, 8A: Motor (travel motor), 10: Oil flow path, 12: Oil cooler, 14: Heating section, 16: Heat pipe, 30: Air conditioning unit, 35: Heater core, 37: Flap (switching mechanism), 50: Switching valve

Claims

1. an oil flow path that supplies oil to a drive motor of the vehicle; a heating unit that heats air used to heat the passenger compartment; a heat pipe formed of a heat conductive material and provided across the oil flow path and the heating portion, The heat pipe is a waste heat utilization system that recovers heat generated by the traction motor from the oil at one end and dissipates the heat to the heating section at the other end.

2. an oil cooler provided on the oil flow path to cool the oil; 2. The waste heat utilization system according to claim 1, wherein heat generated by the traction motor is recovered by heat exchange with the oil flowing out of the oil cooler.

3. The heating unit is provided in an air conditioning unit, the air conditioning unit has a heater core; 3. The waste heat utilization system according to claim 2, wherein the air conditioning unit is provided with a switching mechanism that switches between a first state in which the air is introduced into the heating section and a second state in which the air is blocked from the heating section, depending on the temperature of the heater core and the temperature of the oil.

4. 4. The waste heat utilization system according to claim 2, further comprising a switching valve for switching between a state in which the oil from the oil cooler undergoes the heat exchange and flows to the driving motor, and a state in which the oil from the oil cooler does not undergo the heat exchange and flows to the driving motor.

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