JPH11222025A - Heating device for vehicle - Google Patents

Abstract

PROBLEM TO BE SOLVED: To limit heat exchange amount without generating overheat when an exhaust temperature rises, in addition to ensuring sufficient heating ability by the assist of exhaust heat. SOLUTION: An operating fluid receiving exhaust heat by a heat receiving heat exchanger is guided to a radiating heat exchanger by a heat pipe 5 heat exchanging with conditioning air, and heat of the operating fluid flowing in the heat pipe 5 is released to the atmosphere by a radiation control means 8. In this way, according to a rise of exhaust temperature, when a heat exchange amount is made excessive, heat of the operating fluid in the heat pipe 5 is released to the atmosphere through the radiation control means 8 to limit a heat exchange amount, without increasing an engine cooling water temperature.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a vehicle heating system for heating a vehicle interior by using exhaust heat of an engine.

[0002]

2. Description of the Related Art In recent years, the amount of heat generated by an engine has tended to gradually decrease due to lean combustion for the purpose of improving fuel efficiency and reducing emissions, and a conventional heating system utilizing the heat of engine cooling water has a shortage of heating heat. Therefore, many heating devices using exhaust heat of the engine have been proposed as an auxiliary. For example, in Japanese Unexamined Utility Model Publication No. Hei 2-7689, a heat receiving portion is provided in an exhaust path of an engine, and a heat radiating portion is provided in an air duct of an air conditioner, and a working fluid evaporated by exhaust heat in the heat receiving portion is heat piped. Through the radiator to exchange heat with the conditioned air flowing through the air duct, and then return the condensed and liquefied working fluid to the heat receiver with a heat pipe. Heat exchange.

[0003] In this vehicle heating device, when the heat exchange amount becomes excessive due to an increase in the exhaust gas temperature, such as in summer or during high-load operation, a condenser using engine cooling water is used. The steam in the heat pipe is condensed and liquefied, temporarily stored in a reserve tank, and the amount of working fluid actually used for heat exchange is reduced to prevent overheating of the conditioned air.

[0004]

The conventional vehicle heating system limits the amount of heat exchange by absorbing excess heat generated by the increase in exhaust gas temperature into the engine cooling water as described above. At the time of such a high-load operation or in summer, there is not much thermal margin of the vehicle cooling system, so that there is a possibility that overheating may occur as the cooling water temperature rises.

On the other hand, in addition to the heating device in which the radiating section directly heats the conditioned air as described above, the radiating section heats the engine cooling water flowing through the heating heater core, and indirectly controls the conditioned air by the heater core. There is also a heating system that warms the room. However, even in such a heating device, not only the risk of overheating may be caused by implementing the above-described countermeasures using the condenser, but also in the first place, an excessive amount of heat exchange is directly linked to an increase in the temperature of the cooling water. Prevention of overheating has been an issue.

SUMMARY OF THE INVENTION An object of the present invention is to provide a heating device for a vehicle which can secure a sufficient heating capacity with the aid of exhaust heat and can limit the amount of heat exchange without causing overheating when the exhaust temperature rises. Is to do.

[0007]

In order to achieve the above object, according to the present invention, a working fluid having received exhaust heat of an engine by a heat receiving heat exchanger is guided to a heat radiating heat exchanger by a heat pipe. In addition to directly or indirectly exchanging heat with the conditioned air, the heat of the working fluid flowing through the heat pipe can be released into the atmosphere by the heat radiation control means, so that the amount of heat exchange becomes excessive as the exhaust gas temperature rises. For example, when the heat radiation control means releases the heat of the working fluid in the heat pipe to the atmosphere, the heat exchange amount can be limited without increasing the temperature of the engine cooling water.

[0008]

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS (First Embodiment) A first embodiment of a vehicle heating device embodying the present invention will be described below. FIG.
As shown in FIG. 1, a heater core 2 for heating is disposed in an air duct 1 for air conditioning of a vehicle, and engine coolant is circulated in the heater core 2 through an introduction pipe 3 and a discharge pipe 4 in the direction of the arrow. Although not shown, air is blown in the air duct 1 in the direction of the arrow by a fan, and the air warmed by the heater core 2 is mixed with air cooled by an evaporator according to the switching of the damper and introduced into the vehicle interior. Thus, heating, cooling, and dehumidification are appropriately performed.

A heat radiating portion 5 is provided in the introduction pipe 3 of the heater core 2.
a (shown by a solid line) is interposed, and the heat radiating portion 5a is connected to a heat receiving portion 5b provided in an exhaust path 6 of the engine by a heat pipe 5 while keeping the inside airtight. The heat receiving portion 5b is located lower than the heat radiating portion 5a, and a working fluid such as water or alcohol is sealed in the heat receiving portion 5b. When the heat receiving section 5b is heated by the heat of the exhaust gas flowing through the exhaust path 6, the internal working fluid evaporates and is guided as steam through the heat pipe 5 to the heat radiating section 5a. The cooling water flowing through the introduction pipe 3 is heated. On the other hand, the working fluid condensed and liquefied by the heat exchange is returned to the heat receiving portion 5b along the inner wall of the heat pipe 5, and heat exchange between the exhaust heat and the cooling water is performed by repeating this cycle.

As shown in FIGS. 1 to 3, an intermediate portion of the heat pipe 5 is extended to an inside of an engine room 7 of the vehicle and provided with a heat radiation control unit 8, and is provided from the front of the vehicle or below the floor via a front grill or the like. The radiation control unit 8 is exposed to the introduced traveling wind S. Heat dissipation control unit 8
The main body case 9 has a cylindrical shape extending vertically, an upper part thereof being an upper tank 10, a lower part being a lower tank 11, and a core portion 12 between both tanks 10 and 11. The core portion 12 includes a number of tubes 12a extending vertically and each tube 12a.
The upper tank 10 and the lower tank 11 communicate with each other via the tubes 12a. Since each tube 12a is arranged in a direction perpendicular to the flow of the traveling wind S, the traveling wind S passes rearward from the front of the core portion 12 through the tubes 12a, and the fins 12b With each tube 1
Cool 2a.

On the upper and lower sides of the main body case 9, there are disposed cylindrical heat insulating covers 13a and 13b having the same diameter as the bottom. The heat insulating covers 13a and 13b, the upper surfaces of the upper tank 10 and the lower tank 11 are provided. A heat insulating material 14 is filled between the two tanks 10 and 11 to keep the temperature of the two tanks 10 and 11 constant. A slightly large-diameter shielding ring 15 is fitted on the outer peripheral side of the main body case 9, and an actuator 16 is connected to one side of the shielding ring 15. , And can be switched between two positions: an open position where the core 12 is exposed as indicated by a solid line, and a closed position where the core 12 is hidden as indicated by a virtual line. still,
As the actuator 16, a known method such as a motor or a solenoid can be used.

An ECU (Electronic Control Unit) 17 is connected to the actuator 16, and a water temperature sensor 18 for detecting engine cooling water and a vehicle-mounted automatic air conditioner 19 are connected to the ECU 17. Although not described in detail, ECU
Reference numeral 17 denotes control of the automatic air conditioner 19 based on a set temperature input by the driver (specifically, control of a fan, a damper, a compressor, and the like), fuel injection based on a detection value of each sensor such as a water temperature sensor 18, and the like. It comprehensively controls the engine such as the ignition timing, and includes an input / output device (not shown), a storage device, a central processing unit, and the like.

Next, the operation of the vehicle heating system of this embodiment will be described. Now, when the vehicle engine is started, E
The CU 17 drives and controls the actuator 16 to switch the shield ring 15 of the heat radiation control unit 8 to the closed position indicated by the phantom line. When the operation of the engine is continued, first, the temperature of the exhaust gas starts to rise before the rise of the cooling water temperature, the heat receiving portion 5b of the heat pipe 5 is heated, and the above-mentioned heat exchange is performed by evaporation of the working fluid inside. Cycle is started. At this time, since the core portion 12 of the heat radiation control portion 8 is shielded from the traveling wind S by the shielding ring 15, the steam in the heat pipe 5 is guided to the heat radiation portion 5a without being cooled by the core portion 12, The temperature of the heat radiating portion 5a is quickly raised.
As a result, the cooling water flowing in the introduction pipe 3 is heated, and the temperature rise of the heater core 2 is promoted. Even at this time when the engine cooling water temperature is still low, heating and dehumidification using the heater core 2 can be performed.

When the temperature of the cooling water of the engine gradually rises and exceeds a first preset value, the ECU 1
7 switches the shield ring 15 of the heat radiation control unit 8 to the open position indicated by the solid line by the actuator 16. This first set value is set as a sufficiently high temperature that can be used for heating and dehumidification. Since the switching of the shielding ring 15 exposes the core 12 to the traveling wind S, the steam that has reached the core 12 through the heat pipe 5 is cooled in the tube 12a, condensed and liquefied, and heat-received. The cooling water is returned to 5b, and the heating of the cooling water in the radiator 5a is stopped. Therefore, the subsequent cooling water is continuously heated using only the heat generated by the engine as a heat source, and the temperature of the heater core 2 is maintained by the cooling water.

Further, when an operation state in which the engine calorific value is low, such as an idling operation, is continued and the cooling water temperature becomes equal to or lower than a second set value slightly lower than the first set value, E is reached.
The CU 17 is again actuated by the actuator 16 with the shielding ring 15.
Is switched to the closed position, the heat exchange cycle of the working fluid is restarted, and the temperature rise of the heater core 2 is promoted. Therefore, by repeating this, the heater core 2 is always kept in a state usable for heating and dehumidification.

That is, in the heating apparatus according to the present embodiment, the exhaust heat is used to supplement the temperature of the heater core 2 only when the engine calorific value is low and the cooling water temperature is low, such as immediately after starting or during idling. When the cooling water temperature rises, the heating by the exhaust heat is stopped assuming that it is unnecessary. Therefore, when the exhaust gas temperature rises as in summer or during high-load operation, the heating by the exhaust heat is stopped immediately when the cooling water temperature exceeds the first set value, the amount of heat exchange is limited, and the cooling water temperature is reduced. Ascent is prevented.

Since the exhaust heat which has become unnecessary due to the rise of the cooling water temperature is radiated to the atmosphere from the core portion 12 of the radiation control section 8 as described above, for example, the excess heat described in the prior art is used for the engine. There is no danger of causing a further rise in the temperature of the cooling water as in a heating device of the type that absorbs the cooling water. Therefore, even when the thermal margin of the vehicle cooling system is not so large, such as in summer or during high-load operation, it is possible to prevent the engine from overheating.

(Second Embodiment) Next, a second embodiment in which the present invention is embodied in another vehicle heating device will be described. The difference from the first embodiment described above lies in the configuration of the heat radiation control unit 21 and the control contents of the ECU 17 regarding the shielding ring 26, and the overall system configuration is the same as that of the first embodiment.
Therefore, differences will be mainly described.

As shown in FIGS. 4 and 5, the upper tank 22 and the lower tank 23 of the heat radiation control section 21 of this embodiment are formed independently of each other at a predetermined interval, and the upper tank 22 is located on the side of the heat radiation section 5a. The inside of the lower tank 23 communicates with the heat pipe 5 on the side of the heat receiving section 5b. A working fluid is sealed in the upper tank 22 in the same manner as the heat receiving section 5b. The lower surface 22a of the upper tank 22 and the upper surface 23a of the lower tank 23 are formed as two planes parallel to each other, and the both surfaces 22a, 23a are formed of a plurality of rod-shaped heat conducting members 24.
It is connected by. These heat conducting members 24 are made of a material having a high heat conductivity such as copper, and are arranged dispersedly over the entire lower surface 22a and upper surface 23a.

When the heat receiving portion 5b is heated by the heat of the exhaust gas, the evaporated working fluid is guided to the inside of the lower tank 23 through the heat pipe 5, and the heat is transmitted to the upper tank 22 through the heat conducting member 24. Is done. As a result, the working fluid in the upper tank 22 evaporates and is guided as steam through the heat pipe 5 to the heat radiating portion 5a, and the heat heats the cooling water in the introduction pipe 3. The working fluid in the lower tank 23 is condensed and liquefied by heat exchange and returned to the heat receiving portion 5b. Similarly, the working fluid in the heat radiating portion 5a is condensed and liquefied and returned to the upper tank 22, and the above cycle is repeated. It is.

That is, in the present embodiment, the heat conduction utilizing the heat conducting member 24 is interposed between the heat exchange cycles by the working fluid, and the number, thickness, material and the like of the heat conducting member 24 are determined. By making appropriate changes, it is possible to arbitrarily set the maximum value of the amount of heat exchange between the exhaust gas and the cooling water. The upper side of the upper tank 22 and the lower side of the lower tank 23 are covered by bottomed cylindrical heat insulating covers 25a and 25b,
Due to the heat insulating material 27 filled therein, both tanks 22,
23 are kept warm. Insulation covers 25a, 25b
A slightly large-diameter shielding ring 26 is externally fitted on the outer peripheral side of the
At two positions opposed to each other by 180 degrees, a rectangular ventilation opening 26a is provided. The shield ring 26 is rotated in the direction of the arrow in FIG. 5 by the drive of an actuator (not shown), so that the traveling wind S passes between the heat conducting members 24 through the two ventilation ports 26a. The position can be switched between two positions, that is, a closed position indicated by a virtual line that rotates 90 degrees to block the passage of the traveling wind S.

The radiation control unit 21 is configured as described above. When a driver inputs a desired set temperature to the auto air conditioner 19 during operation of the vehicle, the ECU 17 determines the actual vehicle interior temperature. Fans, dampers,
Controls compressors and the like. Although this control content is very general, in addition, in this embodiment, the ECU 17 determines that the control mode of the auto air conditioner 19 is heating or dehumidification, and, for example, immediately after the start of heating, the actual vehicle interior temperature and the set temperature. When the maximum heating capacity is required for the heater core 2, for example, when the difference between the heater core 2 and the heater core 2 is large, the shield ring 26 of the heat radiation control unit 21 is switched to the closed position indicated by the phantom line in FIG. 5.

As described above, the heat exchange by the working fluid from the heat receiving portion 5b to the lower tank 23, the heat conduction by the heat conducting member 24 from the lower tank 23 to the upper tank 22, and the working fluid from the upper tank 22 to the heat radiating portion 5a. At this time, since the heat conducting member 24 is shielded from the traveling wind S by the shielding ring 26, the heat of the lower tank 23 is conducted to the upper tank 22 without being cooled by the heat conducting member 24. You. As a result, the temperature of the heat radiating portion 5a rises, and the temperature of the heater core 2 is promoted, so that the temperature in the vehicle compartment is quickly raised.

Further, when the temperature in the passenger compartment rises due to the above operation, and the damper is opened and closed to limit the heating of the conditioned air by the heater core 2, that is, when the heater core 2 is not required to have the maximum heating capability, The ECU 17 switches the shield ring 26 of the heat radiation control unit 21 to the open position indicated by the solid line. Therefore, since the traveling wind S passes between the heat conducting members 24 and cools, the heat of the lower tank 23 is hardly conducted to the upper tank 22 side, and the evaporation of the working fluid in the upper tank 22 is interrupted, and The heating of the cooling water in 5a is stopped.

As described above, in the heating device of the present embodiment, only when the maximum heating capacity is required for the heater core 2,
The temperature rise of the heater core 2 is promoted by utilizing the exhaust heat as a supplement, and otherwise, the heating by the exhaust heat is stopped assuming that it is unnecessary. Therefore, similarly to the first embodiment, even when the exhaust gas temperature rises, such as in summer or during a high-load operation, an increase in the cooling water temperature is prevented by the restriction of the heat exchange amount. Further, the exhaust heat that has become unnecessary is dissipated to the radiation control unit 21.
Since heat is radiated to the atmosphere from the heat conducting member 24,
There is no danger of causing a rise in cooling water temperature, and it is possible to prevent engine overheating from occurring even when there is not much thermal margin in the vehicle cooling system, such as in summer or during high-load operation. .

In the first and second embodiments, the cooling water flowing through the heater core 2 is heated using the exhaust heat, and the conditioned air is heated by the heater core 2. That is, although the heat of the exhaust gas and the conditioned air are indirectly exchanged with heat, the present invention is not limited to this, and it is sufficient that the conditioned air is heated by the exhaust heat via the working fluid. Therefore, for example, as shown by a phantom line in FIG. 1, the heat radiating portion 5a of the heat pipe 5 may be provided in the air duct 1 so that the conditioned air is directly heated by the heat of the working fluid.

In the first and second embodiments,
Although the shielding rings 15 and 26 of the heat release control units 8 and 21 are switched between the open position and the closed position, the present invention is not limited to this. Any material can be used as long as heat can be radiated from the core 12 and the heat conducting member 24 of the control units 8 and 21 to the atmosphere. Therefore, for example, in the first embodiment, the shielding ring 15 is gradually opened in accordance with the rise in the temperature of the engine cooling water, and in the second embodiment, the shielding ring 26 is opened in accordance with the decrease in the heating capacity required for the heater core 2.
May be gradually opened.

[0028]

As described above, according to the vehicular heating apparatus of the present invention, the heat of the working fluid flowing through the heat pipe can be released into the atmosphere by the heat radiation control means. When the amount of heat exchange becomes excessive, the heat of the working fluid in the heat pipe is released into the atmosphere by the heat radiating means without being absorbed by the engine cooling water, and the amount of heat exchange is reduced without overheating. Can be restricted.

[Brief description of the drawings]

FIG. 1 is a system diagram showing an overall configuration of a vehicle heating device according to a first embodiment.

FIG. 2 is a cross-sectional view illustrating a heat radiation control unit.

FIG. 3 is a perspective view showing a heat radiation control unit.

FIG. 4 is a cross-sectional view illustrating a heat radiation control unit of the vehicle heating device according to the second embodiment.

FIG. 5 is a perspective view showing a heat radiation control unit.

[Explanation of symbols]

 DESCRIPTION OF SYMBOLS 1 Air duct 5 Heat pipe 5a Heat radiating part (heat radiating heat exchanger) 5b Heat receiving part (heat radiating heat exchanger) 6 Exhaust path 8, 21 Radiation controlling part (radiation controlling means)

Claims (1)

[Claims] 1. A heating device for a vehicle in which auxiliary heating can be performed by utilizing exhaust heat from an engine, wherein a working fluid provided in an exhaust path of the engine and receiving the exhaust heat is enclosed therein. A heat exchanger for heat reception, a heat pipe having one end connected to the heat exchanger for heat reception and guiding the working fluid, and an air conditioning system for the working fluid flowing through the heat pipe connected to the other end of the heat pipe. A heat-radiating heat exchanger for exchanging heat with the conditioned air in the air duct; and a heat-radiating control means provided on the heat pipe and capable of releasing the heat of the working fluid guided inside to the atmosphere. A heating device for a vehicle, characterized by: