Vehicle air conditioning system

Abstract

To make a thinner electric wire than a conventional electric wire usable and improve a degree of freedom of layout of an electric wire without inhibiting comfortableness in heating, and can reduce the weight and cost of a vehicle.SOLUTION: An air conditioning device for a vehicle includes a temperature estimation part 80 for estimating a temperature around an electric wire for power supply connected to an electric heater 5. When the temperature around the electric wire estimated by the temperature estimation part 80 is higher than a predetermined temperature, a control part 70 sets a current value supplied to the electric wire to be lower compared to a current value when the temperature is lower than the predetermined temperature.SELECTED DRAWING: Figure 8

Description

[Technical field]

[0001] The present invention relates to a vehicle air conditioner that is mounted on, for example, an automobile. [Background technology]

[0002] In general, in a vehicle air conditioner, a cooling heat exchanger for cooling the air to be conditioned, a heating heat exchanger for heating the air to be conditioned, and an air mix damper for changing the amount of the air to be conditioned passing through the cooling heat exchanger and the heating heat exchanger are housed in an air conditioner casing, and the cold air and the hot air that have passed through the cooling heat exchanger and the heating heat exchanger are mixed to generate conditioned air at a desired temperature. The conditioned air generated in the air conditioner casing is supplied to various parts of the vehicle interior through a defroster passage, a vent passage, a heat passage, etc.

[0003] For example, in the vehicle air conditioners disclosed in Patent Documents 1 to 3, an electric heater composed of a PTC heater is provided as an auxiliary heating device inside the air conditioner casing, and this electric heater increases the speed of heating.

[0004] Furthermore, Patent Documents 4 and 5 disclose specific structures of electric heaters provided in vehicle air conditioners. An electric wire for supplying power is connected to the electric heater, and the electric wire is connected to a harness of the vehicle through a predetermined path set outside the air conditioner casing. [Prior art documents] [Patent documents]

[0005] [Patent Document 1] JP 2018-114778 A [Patent Document 2] JP 2018-95074 A [Patent Document 3] JP 2018-95075 A [Patent Document 4] JP 2007-280902 A [Patent Document 5] JP 2009-190541 A Summary of the Invention [Problem to be solved by the invention]

[0006] Generally, an allowable temperature range is set for electric wires from the viewpoint of protecting the wires, and the thicker the wire, the higher the temperature on the high end of the allowable temperature range. In the case of electric wires used in electric heaters for vehicle air conditioners, a thicker wire diameter is selected with a margin in the allowable temperature range because the current value is large and there is a need to ensure sufficient safety. For example, if the ambient temperature of the wire is 60°C, a 10sq wire is selected to pass a current of 80A through a 1000W PTC heater.

[0007] However, the path through which the electric wires are passed is difficult to set in a straight line and is bent in a complex manner due to the shape of the air conditioning casing, the structure of the vehicle body, the presence of other parts, etc. When passing the electric wires through such a path, if the electric wires are thick, it is difficult to bend them to follow the path, and there is a risk that the space required to pass the electric wires will increase.

[0008] Furthermore, if the electric wire is made thicker, the weight of the electric wire will increase accordingly, making it impossible to achieve a lighter vehicle weight and increasing costs.

[0009] The present invention has been made in consideration of the above-mentioned points, and an object of the present invention is to improve the freedom of layout of electric wires by enabling the use of thinner electric wires than before without impairing comfort during heating, and to reduce the weight and cost of a vehicle. [Means for solving the problem]

[0010] In order to achieve the above object, a first invention provides a vehicle air conditioning system including an electric heater that heats air for air conditioning and a control unit that controls the electric heater, and further includes a temperature estimation unit that estimates the temperature around an electric power supply cable connected to the electric heater, and the control unit reduces the value of the current supplied to the cable when the temperature around the cable estimated by the temperature estimation unit is higher than a predetermined temperature, compared to when the temperature is equal to or lower than the predetermined temperature.

[0011] According to this configuration, the temperature around the electric wire connected to the electric heater is estimated by the temperature estimation unit. When the estimated temperature is low, the current value that can be passed through the electric wire is high, and the control unit passes a relatively high current through the electric wire, thereby ensuring the necessary heating performance of the electric heater. On the other hand, when the estimated temperature is high, the current value that can be passed through the electric wire is lower than when the estimated temperature is low. In this case, the current value supplied to the electric wire is reduced by the control of the control unit, so that a current exceeding the heat resistance temperature of the electric wire can be prevented from passing while using a thin electric wire, ensuring high safety. Note that a high estimated temperature is considered to be a case in which the heating capacity of the electric heater may be low, and therefore a low current value through the electric wire does not pose much of a problem in terms of heating performance.

[0012] A second invention is characterized in that the temperature estimation unit estimates the temperature around the electric wire based on a value output from a heater temperature sensor provided in the electric heater.

[0013] According to this configuration, the temperature of the electric heater is detected by the heater temperature sensor. Since the electric wire is connected to the electric heater, the electric heater and the electric wire are close to each other. Therefore, by estimating the temperature around the electric wire using the temperature of the electric heater detected by the heater temperature sensor, the estimation result is accurate.

[0014] A third invention is characterized in that the temperature estimation unit estimates the temperature around the electric wire based on a value output from an inside air temperature sensor that detects a temperature inside the vehicle compartment.

[0015] That is, the inside air temperature sensor is provided in a typical vehicle air conditioner and constantly detects the temperature inside the vehicle cabin. Since the electric heater and the electric wire are provided inside the vehicle cabin, the inside air temperature sensor can indirectly detect the temperature around the electric wire. Therefore, by estimating the temperature around the electric wire using the temperature inside the vehicle cabin detected by the inside air temperature sensor, the estimation result is accurate.

[0016] A fourth invention is characterized in that the temperature estimation unit estimates the temperature around the electric wire based on a value output from a coolant temperature sensor that detects the coolant temperature of an engine mounted on a vehicle.

[0017] That is, a coolant temperature sensor is provided in a general vehicle equipped with an engine and constantly detects the coolant temperature. If the coolant temperature is low, it can be estimated that the temperature inside the vehicle cabin, i.e., the space in which the electric wire is installed, is low, and if the coolant temperature is high, it can be estimated that the temperature in the space in which the electric wire is installed is high. Therefore, by estimating the temperature around the electric wire using the coolant temperature detected by the coolant temperature sensor, the estimation result can be made accurate.

[0018] A fifth invention is characterized in that the temperature estimation unit estimates the temperature around the electric wire based on the elapsed time from the start of supply of power to the electric heater.

[0019] That is, before power is supplied to the electric heater, the air for air conditioning is not heated by the electric heater, so it can be estimated that the temperature around the electric wire is low. On the other hand, when power supply to the electric heater is started, the air for air conditioning is heated by the electric heater, so the temperature around the electric wire becomes higher than before heating. Therefore, the temperature of the electric wire increases as time passes from the start of power supply to the electric heater, so that the estimation result is accurate by estimating the temperature around the electric wire based on the elapsed time from the start of power supply to the electric heater.

[0020] A sixth invention is characterized in that the temperature estimation unit estimates that the temperature around the electric wire is higher as the value of the current supplied to the electric heater is larger.

[0021] The larger the current value supplied to the electric heater, the greater the amount of heating of the air for air conditioning by the electric heater, and therefore the higher the temperature around the electric wire. In this configuration, the estimation result of the temperature around the electric wire is accurate based on the current value supplied to the electric heater.

[0022] A seventh invention is characterized in that the vehicle air conditioning system has a heater core through which cooling water of an engine mounted in the vehicle circulates as a main heating device, and the electric heater is an auxiliary heating device.

[0023] According to this configuration, since the electric heater is an auxiliary heating device, it is mainly used for heating at low temperatures. Therefore, even if the current value is low when the temperature around the electric wire is high, the comfort of the passengers is not impaired.

[0024] An eighth invention is characterized in that the control unit sets the current value supplied to the electric wire to 0 when the temperature around the electric wire estimated by the temperature estimation unit is higher than a predetermined temperature.

[0025] According to this configuration, when the temperature around the electric wire is high, heating by the electric heater may not be necessary, so the comfort of the occupants can be suppressed by setting the current value supplied to the electric wire to zero to suppress heat generation by the electric wire. Effect of the Invention

[0026] According to the present invention, when the temperature around the electric wire is higher than a predetermined temperature, the value of the current supplied to the electric wire can be made lower than when the temperature around the electric wire is lower than a predetermined temperature. This makes it possible to use thinner electric wires than before without impairing comfort during heating, thereby improving the freedom of layout of the electric wires and reducing the weight and cost of the vehicle. [Brief description of the drawings]

[0027] [Figure 1] 1 is a front view of a vehicle air conditioning device according to an embodiment of the present invention; [Diagram 2] FIG. 2 is a rear view of the vehicle air conditioning device. [Diagram 3] FIG. 2 is a left side view of the vehicle air conditioning device. [Figure 4] FIG. 2 is a right side view of the vehicle air conditioning device. [Diagram 5] 3 is a cross-sectional view taken along line VV in FIG. 2. [Figure 6] FIG. 4 is a perspective view of the auxiliary heater as viewed from the downstream side in the air flow direction. [Figure 7] FIG. 4 is a view of the auxiliary heater as seen from the downstream side in the air flow direction. [Figure 8] FIG. 2 is a block diagram of a heating system. [Figure 9] 1 is a graph showing the relationship between a current value and an ambient temperature of an electric wire. DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS

[0028] Hereinafter, the embodiments of the present invention will be described in detail with reference to the drawings. Note that the following description of the preferred embodiments is merely illustrative in nature and is not intended to limit the present invention, its applications, or its uses.

[0029] FIG. 1 is a view of a vehicle air conditioner 1 according to an embodiment of the present invention as viewed from the front side of the vehicle, FIG. 2 is a view of the vehicle air conditioner 1 as viewed from the rear side of the vehicle, FIG. 3 is a view of the vehicle air conditioner 1 as viewed from the left side of the vehicle, and FIG. 4 is a view of the vehicle air conditioner 1 as viewed from the right side of the vehicle.

[0030] The vehicle air conditioner 1 is mounted on a vehicle such as an automobile to condition the passenger compartment, and as shown in FIG. 5, includes an air conditioning casing 2, a cooling heat exchanger 3, a heating heat exchanger 4, an auxiliary heater (auxiliary heating device) 5, an upper air mix damper 6, a lower air mix damper 7, a defroster damper 8, a front seat vent damper 9, and a heat damper 10.

[0031] Although not shown, the vehicle air conditioner 1 also includes a blower unit. The blower unit has a blower casing and a blower, and is disposed on the passenger seat side of the vehicle compartment. The blower is composed of a sirocco fan and a motor for rotating the sirocco fan. The blower casing is configured to be able to select either the air inside the vehicle compartment or the air outside the vehicle compartment and introduce it as air for air conditioning, and the air for air conditioning introduced into the blower casing is sent to the air conditioning casing 2 by the blower. The amount of air for air conditioning can be changed by the voltage applied to the motor.

[0032] The air conditioning casing 2 and the air blower casing are arranged side by side in the vehicle width direction (vehicle left-right direction) and are housed inside an instrument panel (not shown) provided at the front end of the passenger compartment. The air conditioning casing 2 and the air blower casing may be configured as one unit or may be configured separately. The air conditioning casing 2 and the air blower casing may be configured to be arranged in the center of the vehicle width direction without being arranged side by side in the vehicle width direction. Also, the air conditioning casing 2 and the air blower casing are connected. Also, in the description of this embodiment, the front side of the vehicle will be simply referred to as the "front", the rear side of the vehicle will be simply referred to as the "rear", the left side of the vehicle will be simply referred to as the "left", and the right side of the vehicle will be simply referred to as the "right".

[0033] Although not shown, an engine room in which an engine is mounted is provided in front of the passenger compartment of the vehicle. A compressor, a condenser, and other components that constitute a refrigeration cycle are disposed in the engine room. A motor for driving the vehicle may be mounted instead of the engine.

[0034] (Configuration of vehicle air conditioner) The air conditioning casing 2 is configured by combining, for example, a plurality of resin members, and is a member that houses a cooling heat exchanger 3, a heating heat exchanger 4, an auxiliary heater 5, an upper air mix damper 6, a lower air mix damper 7, a defroster damper 8, a front seat vent damper 9, and a heat damper 10. The division structure of the air conditioning casing 2 is not particularly limited, but can be, for example, in the front-rear direction or the up-down direction. In this embodiment, as shown in Figs. 1 to 4, the air conditioning casing 2 is divided into a front casing member 2A and a rear casing member 2B, and the front casing member 2A is divided in the up-down direction and the rear casing member 2B is divided in the left-right direction. Therefore, the air conditioning casing 2 is configured by combining four members.

[0035] As shown in Fig. 4, an air inlet 2a is formed in the right wall portion at the front part of the air conditioning casing 2 to introduce the air for conditioning sent from the blower unit into the inside of the air conditioning casing 2. The vehicle air conditioner 1 is configured so that the temperature of the air for conditioning introduced from the air inlet 2a can be adjusted by the cooling heat exchanger 3, the heating heat exchanger 4, and the auxiliary heater 5. Although details will be described later, the amount of air that passes through the heating heat exchanger 4 and the auxiliary heater 5 out of the air that has passed through the cooling heat exchanger 3 is set by the upper air mix damper 6 and the lower air mix damper 7.

[0036] An intermediate duct portion 2C is integrally formed on the periphery of the air inlet 2a in the air conditioning casing 2. As shown in Fig. 2, the intermediate duct 2C is formed so as to protrude to the right. The air blower casing is connected to the right end of this intermediate duct 2C, and the air for air conditioning blown from the air blower casing flows into the air inlet 2a via the intermediate duct 2C. Note that the air inlet 2a is formed on the side where the air blower casing is disposed, but it may be formed on either the left side wall portion or the right side wall portion of the front part of the air conditioning casing 2.

[0037] As shown in Fig. 5, a defroster outlet 2b for supplying conditioned air toward the inner surface of the windshield of the vehicle is formed on the front side of the upper wall of the air conditioning casing 2. This defroster outlet 2b is elongated in the left-right direction. A defroster duct (not shown) is connected to the defroster outlet 2b. The downstream end of the defroster duct is connected to a defroster port (not shown) formed in the front end of the instrument panel.

[0038] A front seat vent outlet 2c is formed on the upper wall of the air conditioning casing 2 behind the defroster outlet 2b to supply conditioned air toward the upper body of the passenger sitting in the front seat. A vent duct (not shown) is connected to the front seat vent outlet 2c. The downstream end of the vent duct is connected to a center vent port (not shown) formed in the approximate center of the instrument panel in the vehicle width direction and side vent ports (not shown) formed on both sides of the instrument panel in the vehicle width direction. The defroster outlet 2b and the front seat vent outlet 2c are arranged to be aligned in the front-rear direction.

[0039] A heat outlet 2d is formed on the lower side of the rear wall of the air conditioning casing 2 to supply conditioned air toward the vicinity of the feet of the passengers. A heat duct (not shown) is connected to the heat outlet 2d. The heat duct is made up of a front heat duct that extends to the vicinity of the feet of the front seat passengers and a rear heat duct that extends to the vicinity of the feet of the rear seat passengers, and is capable of supplying conditioned air to the vicinity of the feet of the front seat passengers and the rear seat passengers. The heat duct may be made up of only the front heat duct. Also, multiple heat outlets 2d may be provided.

[0040] Inside the air conditioning casing 2, an air introduction passage R1, an upper hot air generation passage R2a, a lower hot air generation passage R2b, a defroster passage R3, a front seat vent passage R4, a heat passage R5, an upper passage R6a, and a lower passage R6b are formed. The air introduction passage R1 is formed in the front part inside the air conditioning casing 2. The upstream end of the air introduction passage R1 is connected to the air introduction port 2a. The air introduction passage R1 extends from the air introduction port 2a to the rear side. A cooling heat exchanger 3 is disposed at the downstream end of the air introduction passage R1.

[0041] The cooling heat exchanger 3 is for cooling the air for air conditioning flowing through the air introduction passage R1. The cooling heat exchanger 3 is located at the front side inside the air conditioning casing 2, and its air passing surface is oriented so as to extend in the vertical direction. The upper and lower parts of the cooling heat exchanger 3 are held by the air conditioning casing 2.

[0042] In this embodiment, the cooling heat exchanger 3 is composed of an evaporator (refrigerant evaporator) having a header tank, tubes, and fins (not shown). The evaporator is a component of a conventionally known refrigeration cycle device. The air for air conditioning is cooled by heat exchange between a low-temperature refrigerant flowing inside the cooling heat exchanger 3 and the air for air conditioning passing outside the cooling heat exchanger 3. Condensed water generated on the surface of the cooling heat exchanger 3 at this time is discharged to the outside of the air conditioning casing 2 from the drain pipe portion 2f shown in Figures 1 to 4. The air introduction passage R1 is also a cold air generation passage that generates cold air.

[0043] The heating heat exchanger 4 is disposed in the vertical middle of the air conditioning casing 2, downstream (rear) of the cooling heat exchanger 3 in the air flow direction. Therefore, the cooling heat exchanger 3 is disposed forward of the heating heat exchanger 4. The heating heat exchanger 4 is disposed away from the cooling heat exchanger 3 on the rear side, and a space is provided between the heating heat exchanger 4 and the cooling heat exchanger 3. The heating heat exchanger 4 is oriented such that its air passing surface extends in the vertical direction.

[0044] Between the heating heat exchanger 4 and the cooling heat exchanger 3, a partition wall portion 21 is provided so as to extend in the vertical direction. An upper hot air generating passage R2a and a lower hot air generating passage R2b are formed behind the partition wall portion 21. The upper hot air generating passage R2a and the lower hot air generating passage R2b are formed in the middle part in the front-rear direction and the middle part in the vertical direction inside the air conditioning casing 2, and the lower hot air generating passage R2b is located below the upper hot air generating passage R2a. The upper hot air generating passage R2a and the lower hot air generating passage R2b are formed so as to extend rearward from the partition wall portion 21. Although not shown, a partition plate extending in the front-rear direction may be disposed between the upper hot air generating passage R2a and the lower hot air generating passage R2b.

[0045] A heating heat exchanger 4 is disposed in the upper hot air generating passage R2a and the lower hot air generating passage R2b. Approximately the upper half of the heating heat exchanger 4 is disposed in the upper hot air generating passage R2a, and approximately the lower half of the heating heat exchanger 4 is disposed in the lower hot air generating passage R2b. The heating heat exchanger 4 is composed of a heater core having a header tank, tubes, and fins (not shown), and engine cooling water circulates through this heater core. The heating heat exchanger 4 is the main heating device.

[0046] The heating heat exchanger 4 is supplied with engine cooling water circulating through an engine (not shown) mounted on a vehicle through a supply pipe 4a (shown in Figs. 1 and 3). The engine cooling water supplied to the heating heat exchanger 4 exchanges heat with the air for air conditioning passing through the outside of the heating heat exchanger 4, thereby heating the air for air conditioning. The engine cooling water supplied to the heating heat exchanger 4 is returned to the engine through a discharge pipe 4b (shown in Figs. 1 and 3). The front sides of the supply pipe 4a and the discharge pipe 4b are held by a bracket 2g (shown in Figs. 1 and 3) provided at the front of the air conditioning casing 2. The upper and lower parts of the heating heat exchanger 4 are held by the air conditioning casing 2. The dimension of the heating heat exchanger 4 in the front-rear direction (the dimension in the direction in which the outside air passes) is set shorter than the dimension of the cooling heat exchanger 3 in the front-rear direction. The heating heat exchanger 4 may be constituted by a condenser of a refrigeration cycle.

[0047] The auxiliary heater 5 is disposed in the vertical middle of the air conditioning casing 2, downstream (rear) of the heating heat exchanger 4 in the air flow direction. The auxiliary heater 5 is disposed away from the rear of the heating heat exchanger 4, and a small space is formed between the heating heat exchanger 4 and the auxiliary heater 5. The distance between the heating heat exchanger 4 and the auxiliary heater 5 is set narrower than the distance between the heating heat exchanger 4 and the cooling heat exchanger 3.

[0048] The auxiliary heater 5 is located in the upper hot air generating passage R2a and the lower hot air generating passage R2b. The auxiliary heater 5 is oriented such that its air passage surface extends in the vertical direction. Approximately the upper half of the auxiliary heater 5 is disposed in the upper hot air generating passage R2a, and approximately the lower half of the auxiliary heater 5 is disposed in the lower hot air generating passage R2b. The upper part of the auxiliary heater 5 is located below the upper part of the heating heat exchanger 4. In addition, the front-to-rear dimension of the auxiliary heater 5 (the dimension in the direction in which external air passes) is set to be shorter than the front-to-rear dimension of the heating heat exchanger 4. Details of the auxiliary heater 5 will be described later.

[0049] The vertical dimensions of the heating heat exchanger 4 and the auxiliary heater 5 are set shorter than the vertical dimensions of the cooling heat exchanger 3, and inside the air conditioning casing 2, a space is formed above the heating heat exchanger 4 and the auxiliary heater 5, and a space is also formed below the heating heat exchanger 4 and the auxiliary heater 5. These spaces become passages, and specifically, above the heating heat exchanger 4 and the auxiliary heater 5 of the air conditioning casing 2, an upper passage R6a through which the cold air that has passed through the cooling heat exchanger 3 flows is formed, and below the heating heat exchanger 4 and the auxiliary heater 5 of the air conditioning casing 2, a lower passage R6b through which the cold air that has passed through the cooling heat exchanger 3 flows is formed.

[0050] The upstream end of the upper passage R6a is disposed so as to face the upper side of the surface of the cooling heat exchanger 3 downstream in the air flow direction, and is connected to the upper part of the downstream end of the air introduction passage R1. The upper passage R6a extends upward beyond the upper parts of the heating heat exchanger 4 and the auxiliary heater 5. The middle part of the upper passage R6a can be connected to the upstream end of the upper hot air generation passage R2a. An upper air mix damper 6 is disposed between the middle part of the upper passage R6a and the upstream end of the upper hot air generation passage R2a.

[0051] The upper air mix damper 6 is for adjusting the amount of air flowing through the upper hot air generating passage R2a by changing the opening degree of the upstream end of the upper hot air generating passage R2a. The upper air mix damper 6 is provided with a rotating shaft 6a extending in the left-right direction and a closing plate portion 6b extending in the radial direction from the rotating shaft 6a. Both left and right ends of the rotating shaft 6a are rotatably supported on both left and right side walls of the air conditioning casing 2. The rotating shaft 6a is disposed near the upper portion of the heating heat exchanger 3. The closing plate portion 6b can be switched from a state in which the upstream end of the upper hot air generating passage R2a is fully closed (as shown in FIG. 5) to a state in which the upstream end of the upper hot air generating passage R2a is fully opened (not shown), by rotating upward, and can be stopped at any position between the fully closed state and the fully open state. When the upper air mix damper 6 fully opens the upstream end of the upper hot air generating passage R2a, the downstream side of the upper passage R6a is blocked by the blocking plate portion 6b, and the cold air in the upper passage R6a flows into the upper hot air generating passage R2a. This is the fully hot state. When the upper air mix damper 6 fully closes the upstream end of the upper hot air generating passage R2a, the downstream side of the upper passage R6a is fully opened by the blocking plate portion 6b, and the cold air in the upper passage R6a no longer flows into the upper hot air generating passage R2a. This is the fully cold state.

[0052] The upstream end of the lower passage R6b is disposed so as to face the lower side of the surface of the cooling heat exchanger 3 downstream in the air flow direction, and is connected to the lower part of the downstream end of the air introduction passage R1. Therefore, the cold air flowing out from the air introduction passage R1 flows into both the upper passage R6a and the lower passage R6b. The lower passage R6b extends from the rear of the cooling heat exchanger 3, passing under the heating heat exchanger 4 and the auxiliary heater 5, toward the rear side of the heating heat exchanger 4 and the auxiliary heater 5, and reaches the lower rear side of the air conditioning casing 2. The lower passage R6b extends from the lower rear side of the air conditioning casing 2 while curving upward, and extends along the rear wall of the air conditioning casing 2 until it reaches the upper part of the air conditioning casing 2.

[0053] The lower passage R6b has a middle portion that can communicate with the upstream end of the lower hot air generating passage R2b. A lower air mix damper 7 is disposed between the middle portion of the lower passage R6b and the upstream end of the lower hot air generating passage R2b.

[0054] The lower air mix damper 7 is for adjusting the amount of air flowing through the lower hot air generating passage R2b by changing the opening degree of the upstream end of the lower hot air generating passage R2b. The lower air mix damper 7 is provided with a rotating shaft 7a extending in the left-right direction and a closing plate portion 7b extending in the radial direction from the rotating shaft 7a. The left and right ends of the rotating shaft 7a are separated downward from the rotating shaft 6a of the upper air mix damper 6 and are supported rotatably on both left and right side walls of the air conditioning casing 2. The rotating shaft 7a is disposed near the lower part of the heating heat exchanger 3. The closing plate portion 7b can be switched from a state in which the upstream end of the lower hot air generating passage R2b is fully closed (as shown in FIG. 5) to a state in which the upstream end of the lower hot air generating passage R2b is fully opened (not shown), by rotating downward, and can be stopped at any position between the fully closed state and the fully open state. When the lower air mix damper 7 fully opens the upstream end of the lower hot air generating passage R2b, the lower passage R6b is blocked by the closing plate portion 7b, and the cold air in the lower passage R6b flows into the lower hot air generating passage R2b. This is the fully hot state. When the lower air mix damper 7 fully closes the upstream end of the lower hot air generating passage R2b, the lower passage R6b is fully opened by the closing plate portion 7b, and the cold air in the lower passage R6b does not flow into the lower hot air generating passage R2b. This is the fully cold state.

[0055] The upper air mix damper 6 and the lower air mix damper 7 can be linked by using a well-known link mechanism, and are driven by, for example, an air mix actuator. The air mix actuator is connected to an air conditioning control device (not shown). The air conditioning control device calculates the opening degree of the upper air mix damper 6 and the lower air mix damper 7 based on the temperature set by the occupant, the temperature outside the vehicle cabin, the temperature inside the vehicle cabin, etc., and controls the air mix actuator so that the upper air mix damper 6 and the lower air mix damper 7 are opened to the calculated opening degree.

[0056] When the opening degree of the upper hot air generating passage R2a and the lower hot air generating passage R2b is increased by the air mix actuator, the amount of cold air flowing into the upper hot air generating passage R2a and the lower hot air generating passage R2b increases, so the amount of hot air generated increases, and the temperature of the conditioned air rises. On the other hand, when the opening degree of the upper hot air generating passage R2a and the lower hot air generating passage R2b is reduced by the air mix actuator, the amount of cold air flowing into the upper hot air generating passage R2a and the lower hot air generating passage R2b decreases, so the amount of hot air generated decreases, and the temperature of the conditioned air drops. The upper air mix damper 6 and the lower air mix damper 7 are configured to rotate so that the temperature of the conditioned air can be set to a target temperature.

[0057] The conditioned air generated as described above forms conditioned wind inside the air conditioning casing 2. The conditioned wind is only hot wind generated by the heating heat exchanger 4 and the auxiliary heater 5 during full hot mode, only cold wind generated by the cooling heat exchanger 3 during full cold mode, and a mixture of hot and cold winds between full hot and full cold modes.

[0058] The defroster passage R3 is formed on the upper side inside the air conditioning casing 2, and conditioned air flows inside. The downstream end of the defroster passage R3 is connected to the defroster outlet 2b. The defroster passage R3 communicates with the vehicle interior via the defroster outlet 2b.

[0059] The defroster damper 8 is for opening and closing the defroster passage R3, and includes a rotary shaft 8a extending in the left-right direction, and closing plate portions 8b, 8b extending radially from the rotary shaft 8a. Both left and right ends of the rotary shaft 8a are rotatably supported on both left and right side walls of the air conditioning casing 2. The rotary shaft 8a is disposed in the middle of the defroster passage R3 in the front-rear direction. As the defroster damper 8 rotates around the rotary shaft 8a, the closing plate portions 8b, 8b switch the defroster passage R3 from a fully closed state (shown in FIG. 5) to a fully open state (not shown), and vice versa, and also switch to intermediate opening degrees.

[0060] A front seat vent passage R4 for supplying conditioned air to the upper body of the occupant is formed on the upper side of the air conditioning casing 2 so as to communicate with the downstream side of the upper passage R6a and the downstream side of the lower passage R6b. That is, the front seat vent passage R4 is formed on the upper side of the interior of the air conditioning casing 2, rearward of the defroster passage R3, so that conditioned air flows inside. The front seat vent passage R4 is formed above the heating heat exchanger 4 and forward of the auxiliary heater 5. The downstream end of the front seat vent passage R4 is connected to the front seat vent outlet 2c. The front seat vent passage R4 communicates with the passenger compartment via the front seat vent outlet 2c.

[0061] The front seat vent damper 9 is for opening and closing the front seat vent passage R4, and includes a rotary shaft 9a extending in the left-right direction and a closing plate portion 9b integrated with the rotary shaft 9a. Both left and right ends of the rotary shaft 9a are rotatably supported on both left and right side walls of the air conditioning casing 2. The rotary shaft 9a is disposed closer to the front side. When the front seat vent damper 9 rotates around the rotary shaft 9a, the closing plate portion 9b switches the front seat vent passage R4 from a fully open state (shown in FIG. 5) to a fully closed state (not shown) and vice versa.

[0062] The heat passage R5 is formed below the front seat vent passage R4 inside the air conditioning casing 2, and the conditioned air flows inside. The downstream end of the heat passage R5 is connected to the heat outlet 2d. The heat passage R5 communicates with the vehicle interior via the heat outlet 2d.

[0063] The heat damper 10 is for opening and closing the heat passage R5, and includes a rotating shaft 10a extending in the left-right direction and closing plate portions 10b, 10b extending radially from the rotating shaft 10a. Both left and right ends of the rotating shaft 10a are rotatably supported on both left and right side walls of the air conditioning casing 2. The rotating shaft 10a is disposed near the upper portion of the upstream end of the heat passage R5. When the heat damper 10 rotates around the rotating shaft 10a, the heat passage R5 is fully closed (as shown in FIG. 5) by the closing plate portion 10b located below the rotating shaft 10a. When the heat damper 10 is rotated from this fully closed state until the closing plate portions 10b, 10b are in a position extending in the front-rear direction, the heat damper 10 is switched to a fully open state (not shown). The heat damper 10 can be rotated from the fully open state to the fully closed state by rotating it in the opposite direction. As shown in Fig. 5, when the heat damper 10 is in a fully closed state, the closing plate portion 10b extends in the vertical direction. On the other hand, when the heat damper 10 is in a fully open state, the closing plate portion 10b extends in the front-rear direction. This prevents the air for air conditioning below the heat damper 10 from flowing above the heat damper 10.

[0064] The defroster damper 8, the front seat vent damper 9, and the heat damper 10 can be linked together by using a known link mechanism, and are driven by, for example, an actuator for switching the blowing direction. The actuator for switching the blowing direction is connected to an air conditioning control device (not shown). The air conditioning control device calculates the opening degree of the defroster damper 8, the front seat vent damper 9, and the heat damper 10 based on the temperature set by the occupant, the temperature outside the vehicle compartment, the temperature inside the vehicle compartment, etc., and controls the actuator for switching the blowing direction so that the defroster damper 8, the front seat vent damper 9, and the heat damper 10 are opened to the calculated opening degree. This allows switching to, for example, a vent mode, a defroster mode, a heat mode, a bi-level mode, a defroster heat mode, etc.

[0065] (Configuration of auxiliary heater 5) The auxiliary heater 5 shown in FIG. 6 is an electric heater that heats the air for air conditioning by supplying electric power from the outside, and in this example, it is a PTC heater. That is, the auxiliary heater 5 includes a heating element (not shown) that generates heat by energization, a housing member 51 that houses the heating element, a plurality of heat dissipation fins 52 to which the heat of the heating element is transferred, a left fixing member 53, and a right fixing member 54. The heating element is composed of a PTC element. The housing member 51 can be composed of a metallic cylindrical member extending in the left-right direction, and in this example, three housing members 51 are provided at intervals from each other in the up-down direction. A plurality of heating elements are arranged side by side in the left-right direction inside one housing member 51. Although not shown, a conductor for supplying electric power is connected to each heating element. Electric power is supplied to each heating element 50 from a vehicle battery or the like via a conductor. The amount of electric power supplied and the ON / OFF switching of the power supply are performed by a control unit 70 shown in FIG. 8. The control unit 70 is a part of the vehicle air conditioner 1, and controls the auxiliary heater 5. The control unit 70 is composed of, for example, a microcomputer, processes signals and various values ​​input from the outside according to a predetermined program, and outputs the processing results.

[0066] The left end of the housing member 51 is fixed to the left fixing member 53. In addition, the right end of the housing member 51 is fixed to the right fixing member 54. The left fixing member 53 and the right fixing member 54 are integrated in a connected state by the housing member 51. The right fixing member 54 is fixed to the right side wall portion of the air conditioning casing 2. In addition, the left fixing member 53 is fixed to the left side wall portion of the air conditioning casing 2.

[0067] Each of the heat dissipating fins 52 is made of a metal plate material (e.g., an aluminum alloy plate material) extending in the vertical direction, and in this embodiment, all of the heat dissipating fins 52 are made of the same material. The heat dissipating fins 52 may be, for example, press-molded products.

[0068] As shown in Figs. 6 and 7, the auxiliary heater 5 is connected to electric power supply wires 60 and 61 for supplying power to the auxiliary heater 5. One of the electric wires 60 and 61 is a ground wire. As shown in Fig. 3, the electric wires 60 and 61 extend from the left side wall of the air conditioning casing 2 to the outside of the air conditioning casing 2, and are arranged so as to pass through a predetermined path that has been set in advance. The path of the electric wires 60 and 61 is set depending on the shape of the air conditioning casing 2, the structure of the vehicle body, the positions and shapes of other parts, and the like. In this embodiment, the electric wire 60 extends from the left side wall of the air conditioning casing 2 to the outside, and then extends upward and forward, and the electric wire 61 extends from the left side wall of the air conditioning casing 2 to the outside, and then extends downward and forward, with the tip side extending backward. In this way, the electric wires 60 and 61 are bent in a complex manner. The ends of the electric wires 60 and 61 are adapted to be connected to a harness (not shown) of the vehicle body.

[0069] As shown in Fig. 8, the vehicle air conditioner 1 includes a temperature estimation unit 80 that estimates the temperature around the electric power supply wires 60, 61 connected to the auxiliary heater 5. The temperature estimation unit 80 is configured with, for example, a microcomputer, and processes signals and various values ​​input from the outside according to a predetermined program and outputs the processing results. The control unit 70 and the temperature estimation unit 80 may be configured with a common microcomputer, in which case the internal processing means can be conceptually divided into the control unit 70 and the temperature estimation unit 80.

[0070] 8, the temperature estimation unit 80 is a part that estimates the temperature around the electric wires 60, 16 based on a value (output value) output from any one of the heater temperature sensor 71 provided in the auxiliary heater 5, the interior air temperature sensor 72 that detects the temperature inside the vehicle cabin, and the coolant temperature sensor 73 that detects the temperature of the coolant circulating through the engine mounted on the vehicle. For example, a table showing the relationship between the output values ​​from the sensors 71-73 and the temperatures around the electric wires 60, 16 is obtained in advance by experiment, and the table is stored in the temperature estimation unit 80, whereby an estimate of the temperature around the electric wires 60, 16 can be obtained based on the output values ​​from the sensors 71-73.

[0071] The heater temperature sensor 71 can be attached to, for example, the surface of the auxiliary heater 5, or can be attached downstream of the auxiliary heater 5 in the air flow direction. This allows the heater temperature sensor 71 to detect the temperature of the auxiliary heater 5. Since the electric wires 60, 61 are connected to the auxiliary heater 5, the auxiliary heater 5 and the electric wires 60, 61 are close to each other and both are disposed inside the vehicle cabin. Therefore, if the temperature of the auxiliary heater 5 detected by the heater temperature sensor 71 is high, the temperature around the electric wires 60, 16 is high, whereas if the temperature of the auxiliary heater 5 detected by the heater temperature sensor 71 is low, the temperature around the electric wires 60, 16 is low. The temperature estimation unit 80 can estimate the temperature around the electric wires 60, 16 using the temperature of the auxiliary heater 5 detected by the heater temperature sensor 71. The criterion for whether the temperature around the electric wires 60, 16 is high or low can be a predetermined temperature, which will be described later.

[0072] The inside air temperature sensor 72 is provided in the vehicle air conditioner 1. The inside air temperature sensor 72 is provided, for example, on an instrument panel inside the vehicle cabin. The inside air temperature sensor 72 constantly detects the temperature inside the vehicle cabin as information for setting a target temperature of the conditioned air. Since the auxiliary heater 5 and the electric wires 60, 61 are provided inside the vehicle cabin, the inside air temperature sensor 72 can indirectly detect the temperature around the electric wires 60, 61. Therefore, the temperature estimation unit 80 can estimate the temperature around the electric wires 60, 61 using the temperature inside the vehicle cabin detected by the inside air temperature sensor 72. Both the inside air temperature sensor 72 and the electric wires 60, 61 may be provided inside the instrument panel, in which case the estimation result will be more accurate.

[0073] Further, a coolant temperature sensor 73 is provided in the vehicle and constantly detects the coolant temperature. The coolant temperature is used to control the engine and is also used as information for setting a target temperature of the air conditioning air. For example, if the coolant temperature detected by the coolant temperature sensor 73 is low, the temperature in the vehicle interior, i.e., the space in which the electric wires 60, 61 are provided, is low, so it can be estimated that the temperature around the electric wires 60, 61 is low. On the other hand, if the coolant temperature detected by the coolant temperature sensor 73 is high, the temperature in the space in which the electric wires 60, 61 are provided is high, so it can be estimated that the temperature around the electric wires 60, 61 is high. Therefore, the temperature estimation unit 80 can estimate the temperature around the electric wires 60, 61 using the temperature of the coolant detected by the coolant temperature sensor 73.

[0074] The heater temperature sensor 71, the inside air temperature sensor 72, and the coolant temperature sensor 73 are connected to an ECU 74 provided in the vehicle, and all output values ​​from the sensors 71, 72, and 73 are input to the ECU 74. The ECU 74 and the temperature estimation unit 80 are connected via a communication line 75. The values ​​input to the ECU 74 from the heater temperature sensor 71, the inside air temperature sensor 72, and the coolant temperature sensor 73 are input to the temperature estimation unit 80 via the communication line 75. The heater temperature sensor 71, the inside air temperature sensor 72, and the coolant temperature sensor 73 may be directly connected to the temperature estimation unit 80, and the output values ​​from the sensors 71, 72, and 73 may be input to the temperature estimation unit 80 without the communication line 75. Also, only some of the heater temperature sensor 71, the inside air temperature sensor 72, and the coolant temperature sensor 73 may be directly connected to the temperature estimation unit 80, and the others may be connected to the ECU 74. Also, other temperature sensors may be connected to the ECU 74.

[0075] The temperature estimation unit 80 may estimate the temperature around the electric wires 60, 61 as described above and output the estimated temperature to the control unit 70, or may set, for example, 30°C as a predetermined temperature and estimate whether the temperature around the electric wires 60, 61 is higher than 30°C or lower than 30°C and output the result to the control unit 70. This predetermined temperature can be set, for example, between 10°C and 40°C.

[0076] In addition to the method of estimating the temperature around the electric wires 60, 61 using the output values ​​of the heater temperature sensor 71, the inside air temperature sensor 72, and the coolant temperature sensor 73, the temperature estimation unit 80 may be configured to estimate the temperature around the electric wires 60, 61, for example, based on the elapsed time from the start of the supply of power to the auxiliary heater 5.

[0077] That is, before the supply of power to the auxiliary heater 5, the auxiliary heater 5 does not heat the air for air conditioning, so it can be estimated that the temperature around the electric wires 60, 61 arranged in the vehicle cabin is low. On the other hand, when the supply of power to the auxiliary heater 5 starts, the auxiliary heater 5 heats the air for air conditioning, so the temperature around the electric wires 60, 61 becomes higher than before the heating. Therefore, the temperature of the electric wires 60, 61 increases as time passes from the start of the supply of power to the auxiliary heater 5, and by utilizing this, the temperature estimation unit 80 estimates the temperature around the electric wires 60, 61 based on the elapsed time from the start of the supply of power to the auxiliary heater 5, so that the estimation result becomes accurate. In this case, for example, if the temperature inside the vehicle cabin is low, the temperature around the electric wires 60, 61 is unlikely to rise, so the temperature around the electric wires 60, 61 may be estimated based on both the temperature inside the vehicle cabin and the elapsed time from the start of the supply of power to the auxiliary heater 5. For example, a table specifying the relationship between the temperature inside the vehicle cabin, the time elapsed since the start of power supply to the auxiliary heater 5, and the temperature around the electric wires 60, 61 can be stored in advance in the temperature estimation unit 80, and the temperature around the electric wires 60, 61 can be estimated based on the detected temperature inside the vehicle cabin and the elapsed time.

[0078] Furthermore, the temperature estimation unit 80 may be configured to estimate that the greater the value of the current supplied to the auxiliary heater 5, the higher the temperature around the electric wires 60, 61.

[0079] That is, the larger the current value supplied to the auxiliary heater 5, the greater the amount of heating of the air for conditioning by the auxiliary heater 5, and therefore the faster the rate at which the temperature rises in the vehicle cabin, and on the other hand, the smaller the current value supplied to the auxiliary heater 5, the lower the amount of heating of the air for conditioning by the auxiliary heater 5, and therefore the slower the rate at which the temperature rises in the vehicle cabin. A faster rate at which the temperature rises in the vehicle cabin means a faster rate at which the temperature around the electric wires 60, 61 rises, and estimating the temperature around the electric wires 60, 61 based on the current value supplied to the auxiliary heater 5 makes it possible to obtain accurate estimation results.

[0080] The control unit 70 controls a switch 76 consisting of a MOS-FET or the like. When the switch 76 is turned ON (closed state), current supplied from a power source such as a battery flows through the electric wires 60 and 61 to the auxiliary heater 5, causing the auxiliary heater 5 to generate heat. The value of the current supplied to the auxiliary heater 5 via the switch 76 is controlled by the control unit 70.

[0081] That is, when the temperature around the electric wires estimated by the temperature estimation unit 80 is higher than a predetermined temperature, the control unit 70 reduces the value of the current supplied to the electric wires 60, 61 compared to when the temperature is lower than the predetermined temperature. Furthermore, the control unit 70 may control the switch 76 to set the value of the current supplied to the electric wires 60, 61 to zero when the temperature around the electric wires 60, 61 estimated by the temperature estimation unit 80 is higher than a predetermined temperature.

[0082] 9 is a graph showing the current value controlled by the control unit 70, with the vertical axis showing the current value and the horizontal axis showing the temperature around the electric wire. In the graph, the dashed line shows the allowable current value of a 10 sq electric wire, and the dashed line shows the allowable current value of an 8 sq electric wire, with the allowable current value decreasing as the temperature around each electric wire increases. This is set as the electric wire standard.

[0083] Meanwhile, the solid line in the graph indicates the current value controlled by the control unit 70. Specifically, when the temperature around the electric wires 60, 61 estimated by the temperature estimation unit 80 exceeds 40°C, the control unit 70 limits the current supplied to the auxiliary heater 5 so as not to exceed the allowable current value of an 8sq electric wire. In addition, in a temperature range where the temperature around the electric wires 60, 61 estimated by the temperature estimation unit 80 is lower than 40°C, a current of 74A is supplied to the auxiliary heater 5 so as to enable 1000W output at a voltage of 13.5V. 74A is lower than the allowable current value of an 8sq electric wire in a temperature range lower than 40°C.

[0084] (Operation of vehicle air conditioner 1) Next, the operation of the vehicle air conditioner 1 configured as above will be described. First, the vent mode shown in Fig. 5 will be described. This vent mode is a mode in which the defroster passage R3 and the heat passage R5 are closed and the front seat vent passage R4 is opened. In Fig. 5, the upper air mix damper 6 and the lower air mix damper 7 fully close the upper hot air generation passage R2a and the lower hot air generation passage R2b, so that the cold air that has passed through the cooling heat exchanger 3 flows through the upper passage R6a and the lower passage R6b. In this way, by providing the upper passage R6a and the lower passage R6b, the passage cross-sectional area can be increased and the ventilation resistance can be reduced.

[0085] Since the front seat vent passage R4 is open, the cool air flows into the front seat vent passage R4 and is supplied to each part of the vehicle interior through the front seat vent outlet 2c.

[0086] If the upper air mix damper 6 and the lower air mix damper 7 keep the upper hot air generating passage R2a and the lower hot air generating passage R2b in a half-open state, hot air is generated in the upper hot air generating passage R2a and the lower hot air generating passage R2b, and this hot air and cold air are mixed together to become conditioned air that is supplied to various parts of the vehicle cabin.

[0087] Next, the heat mode will be described. In this heat mode, the front seat vent passage R4 is closed and the defroster passage R3 and the heat passage R5 are opened. When the upper air mix damper 6 and the lower air mix damper 7 fully open the upper hot air generating passage R2a and the lower hot air generating passage R2b, the cold air that has passed through the cooling heat exchanger 3 is heated by the heating heat exchanger 4 while flowing through the upper hot air generating passage R2a and the lower hot air generating passage R2b. The hot air that has flowed through the upper hot air generating passage R2a mainly flows upward and flows into the defroster passage R3, and is supplied to the vehicle compartment from the defroster outlet 2b. The hot air that has flowed through the lower hot air generating passage R2b mainly flows toward the heat passage R5 and is supplied to the vehicle compartment from the heat outlet 2d.

[0088] Next, the defroster mode will be described. In this defroster mode, the defroster passage R3 is opened and the front seat vent passage R4 and the heat passage R5 are closed. When the upper air mix damper 6 and the lower air mix damper 7 fully open the upper hot air generating passage R2a and the lower hot air generating passage R2b, the cold air that has passed through the cooling heat exchanger 3 is heated by the heating heat exchanger 4 while flowing through the upper hot air generating passage R2a and the lower hot air generating passage R2b. The hot air that has flowed through the upper hot air generating passage R2a and the lower hot air generating passage R2b mainly flows upward and enters the defroster passage R3, and is supplied to the vehicle interior from the defroster outlet 2b.

[0089] (Effects of the embodiment) According to the vehicle air conditioner 1 of this embodiment, when the temperature around the electric wires 60, 61 estimated by the temperature estimation unit 80 is higher than a predetermined temperature, the control unit 70 reduces the current value supplied to the electric wires 60, 61 compared to when the temperature is lower than the predetermined temperature. That is, when the temperature estimated by the temperature estimation unit 80 is low, the current value that can be passed through the electric wires 60, 61 is high, so that the control unit 70 can ensure the necessary heating performance by the auxiliary heater 5 by passing a relatively high current through the electric wires 60, 61. On the other hand, when the temperature estimated by the temperature estimation unit 80 is high, the current value that can be passed through the electric wires 60, 61 is lower compared to when the temperature is low. In this case, the current value supplied to the electric wires 60, 61 is reduced by the control of the control unit 70. Therefore, even when a thin electric wire (e.g., an 8sq electric wire) is used, a current exceeding the heat resistance temperature of the electric wires 60, 61 can be prevented from passing, and high safety is ensured. If the estimated temperature is high at this time, it means that the heating capacity of the auxiliary heater 5 may be low, so there is no problem in terms of heating capacity even if the current value flowing through the electric wires 60, 61 is low. Therefore, it is possible to use thinner electric wires 60, 61 than before without impairing comfort during heating, improving the degree of freedom in the layout of the electric wires 60, 61, and achieving weight reduction and cost reduction of the vehicle.

[0090] The above-described embodiment is merely illustrative in all respects and should not be construed as limiting. Furthermore, all modifications and variations within the scope of the claims are within the scope of the present invention. [Industrial Applicability]

[0091] INDUSTRIAL APPLICABILITY As described above, the vehicle air conditioner according to the present invention can be used as an air conditioner mounted in, for example, an automobile. [Explanation of symbols]

[0092] 1. Vehicle air conditioning system 2 Air conditioning casing 5 Auxiliary heater (electric heater, auxiliary heating device) 70 Control section 71 Heater temperature sensor 72 Inside air temperature sensor 73 Coolant temperature sensor 80 Temperature estimation section

Claims

1. an electric heater for heating air for air conditioning; A vehicle air conditioning system including a control unit for controlling the electric heater, a temperature estimation unit that estimates a temperature around an electric wire for supplying power that is connected to the electric heater, The temperature estimation unit estimates a temperature around the electric wire based on a value output from an interior air temperature sensor that detects a temperature inside the vehicle compartment, The control unit, when the temperature around the electric wire estimated by the temperature estimation unit is higher than a predetermined temperature, reduces the value of the current supplied to the electric wire compared to when the temperature is equal to or lower than the predetermined temperature.

2. 2. The vehicle air conditioning system according to claim 1, The vehicle air conditioning device includes a heater core as a main heating device through which coolant for an engine mounted in a vehicle circulates, 13. A vehicle air conditioning system, comprising: the electric heater being an auxiliary heating device.

3. 3. The vehicle air conditioning system according to claim 1, The vehicle air conditioning system according to claim 1, wherein the control unit sets a value of a current supplied to the electric wire to zero when the temperature around the electric wire estimated by the temperature estimation unit is higher than a predetermined temperature.

Images