JPH08258545A - Air conditioner for electric vehicle - Google Patents

Abstract

PURPOSE: To prevent a windshield from a blur at the time of switching to heating operation from cooling operation. CONSTITUTION: Whether dew condensation is generated to a windshield inside a vehicle is predictively computed by a computing means 18 with at least the outside air temperature detected by an outside air sensor 5a, the internal air temperature detected by an internal air sensor 8a and humidity after passing an internal heat exchanger 3, detected by a humidity sensor 3a. At the time of switching to a heating operation mode from a cooling operation mode, an air conditioner control means 18 inhibits switching to the heating operation mode of a heat pump cycle until a signal indicating no generation of dew condensation is outputted from the computing means 18, and also turns on an auxiliary heater 10 provided at an air passage downstream of an interior side heat exchanger 3.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to an air conditioner for an electric vehicle, and more particularly, to an air conditioner for an electric vehicle which prevents fogging of windows when the operation mode is switched from cooling to heating. is there.

[0002]

2. Description of the Related Art Conventionally, in an air conditioner for an electric vehicle, a heat pump cycle consisting of a compressor, a heat exchanger outside the vehicle, an expansion valve and a heat exchanger inside the vehicle is used to change the circulation direction of the heat exchange medium to change the heating operation mode. Alternatively, the mode is switched to the cooling operation mode. In the cooling operation mode, the refrigerant discharged from the compressor is guided from the heat exchanger outside the vehicle to the heat exchanger inside the vehicle to operate the heat exchanger inside the vehicle as an evaporator to cool the inside air or the outside air and blow the air inside the vehicle. In the heating operation mode, the refrigerant discharged from the compressor is guided to the in-vehicle heat exchanger to operate the in-vehicle heat exchanger as a condenser to heat the inside air or the outside air and blow the air into the vehicle.

[0003]

However, in the conventional air conditioner for an electric vehicle, when the cooling operation is switched to the heating operation, the condensed water adhering to the in-vehicle heat exchanger during the cooling operation is rapidly heated. It becomes water vapor and becomes humid blast air, which is blown out toward the inside of the vehicle, so that the front window easily becomes fogged. The fog on the front window deteriorates the visibility of the driver and causes an accident or the like.

The present invention has been made in view of the above problems, and an object of the present invention is to provide an air conditioner for an electric vehicle that does not cause fogging in the front window even when the cooling operation is switched to the heating operation.

[0005]

In order to achieve the above object, the present invention, as set forth in claim 1, comprises a mode selection means for selecting one of the operation modes of cooling and heating,
An in-vehicle heat exchanger that is provided in a heat pump cycle that can be operated in a cooling cycle and a heating cycle by switching the refrigerant circulation direction according to the mode selected by the mode selection means, and that cools or heats the air blown into the vehicle, and the outside of the vehicle Outside temperature detecting means for detecting temperature, inside temperature detecting means for detecting inside temperature, humidity detecting means for detecting air humidity after passing through the inside heat exchanger, at least the outside temperature detecting means, inside temperature detecting means Means for calculating the presence or absence of dew condensation in the vehicle front wind from the vehicle outside temperature, the vehicle interior temperature and the humidity respectively detected by the means and the humidity detecting means, and when the cooling operation mode is switched to the heating operation mode, Prohibit switching to heating operation mode until a signal is issued by the calculation means that no condensation has occurred. It is obtained by a air-conditioning control unit.

Further, according to a second aspect of the present invention, the air conditioner further comprises an auxiliary heater for heating the blown air in the air flow passage on the downstream side of the vehicle interior heat exchanger, and the air conditioner control means cools the air conditioner. When the operation mode is switched to the heating operation mode, the switching to the heating operation mode may be prohibited and the auxiliary heater may be turned on until the calculation unit issues a signal that no condensation occurs.

[0007]

In the air conditioner according to the first aspect of the present invention, when the cooling operation is switched to the heating operation, the calculation means predictively calculates from the outside temperature, the inside temperature and the humidity whether or not dew condensation occurs on the inside front window. The air conditioner control means prohibits the heating operation when it is predicted by this computing means that dew condensation will occur until it is predicted that no dew condensation will occur. As a result, the condensed water that has adhered to the in-vehicle heat exchanger does not evaporate and blow out into the vehicle during the cooling operation, and dew condensation does not occur on the front window.

In the air conditioner according to the second aspect of the present invention, when the cooling operation is switched to the heating operation, the heating operation is prohibited and the auxiliary heater is turned on until the calculation means predicts that no dew condensation will occur. The exchanger does not heat, but the auxiliary heater does. For this reason, the heating desired by the occupant can be achieved while preventing the occurrence of fogging.

[0009]

Next, an embodiment of the present invention will be described with reference to the accompanying drawings. FIG. 1 shows an air conditioner for an electric vehicle according to the present invention. In this device, a heat pump cycle in which a heat exchange medium circulates is formed by the four-way valve 1, the compressor 2, the vehicle interior heat exchanger 3, the expansion valve 4, the vehicle exterior heat exchanger 5, and the accumulator 6.

The four-way valve 1 can be switched between a position shown by a solid line and a position shown by a dotted line by a drive motor 1a. When the four-way valve 1 is switched to the position indicated by the solid line, the heat exchange medium of the heat pump cycle flows in the direction indicated by the solid line to form a heating cycle, and when switched to the position indicated by the dotted line, the heat exchange medium moves in the direction indicated by the dotted line. It flows and becomes a cooling cycle.

The compressor 2 is driven by the electric power supplied from the compressor drive device 7, sucks the heat exchange medium flowing in the heat pump cycle, and discharges it as a high temperature / high pressure state.

The inside heat exchanger 3 and the outside heat exchanger 5 have a structure in which flat tubes and corrugated fins are laminated and integrated, and the heat exchange medium flowing inside the flat tubes and the outside of the flat tubes pass therethrough. It is designed to be able to exchange heat with air.

The in-vehicle heat exchanger 3 is provided in the unit 8 arranged in the front part of the vehicle, and operates as a condenser in the heating cycle and as an evaporator in the cooling cycle. A humidity sensor 3a that detects the humidity of the air is provided in the air flow path on the downstream side of the in-vehicle heat exchanger 3. An inside air sensor 8a for detecting the inside air temperature is provided outside the unit 8. The exterior heat exchanger 5 is attached to the front part of the vehicle, and operates as an evaporator in the heating cycle and as a condenser in the cooling cycle. An outside air sensor 5a for detecting the outside air temperature is provided near the exterior heat exchanger 5.

The accumulator 6 stores a heat exchange medium to separate gas and liquid, and supplies only gas to the compressor 2.

Inside the unit 8, a blower 9 located upstream of the vehicle interior heat exchanger 3, outside the vehicle interior heat exchanger 3, and an auxiliary heater 1 located downstream of the vehicle interior heat exchanger 3.
0 and 0 are provided respectively. Furthermore, the auxiliary heater 1
An outlet position switching unit 11 is provided on the downstream side of 0,
The DEF outlet 13a, the VENT outlet 13b, and the HE are respectively provided by the dampers 12a, 12b, 12c, and 12d.
The AT air outlet 13c and the rear air outlet 13d can be opened and closed.

The blower 9 is a blower air volume setting device 14
The blower air flow rate controller 15 drives the blower air flow rate controller 15 so that a desired air flow rate can be obtained in accordance with the set value input in step 1. The energization of the auxiliary heater 10 is controlled by the auxiliary heater energization control device 16. Each of the dampers 12a to 12d is configured to rotate in conjunction with each other, and the blower mode setting device 17
Each of the predetermined air outlets is opened and closed according to an input signal from.

The input signal from the blower air flow rate setting device 14, the input signal from the blower mode setting device 17, the humidity detected by the humidity sensor 3a, the temperature detected by the outside air sensor 5a,
The temperatures detected by the inside air sensor 8a are input to the air conditioner control device 18, respectively. Further, a mode selection device 19 for selecting the cooling mode or the heating mode and a temperature setting device 20 for setting the air conditioning temperature inside the vehicle are provided, and these input signals are also input to the air conditioner control device 18. Based on these input signals, the air conditioner control device 18 issues control signals to the drive motor 1a of the four-way valve 1, the compressor drive device 7, the auxiliary heater energization control device 16 and the blower air flow control device 15, respectively, to cool and cool the air conditioner. Control heating operation.

The control operation of the air conditioner controller will be described below with reference to the flow chart shown in FIG. First, in step 101, it is judged whether or not the mode selected by the mode selection device 19 is heating, and if it is cooling instead of heating, the heat pump is operated in the cooling cycle in step 102, and the cooling flag is set to 1 in step 103. , Return to step 101. The cooling flag is a flag indicating whether or not the heat pump has been operated in the cooling cycle. When it is 1, it indicates that it has been operated in the cooling cycle, and when it is 0, it indicates that it has not been operated in the cooling cycle.

If the mode selected in step 101 is heating, it is determined in step 104 whether or not the cooling flag is 1, and if it is not 1, it means that the cooling cycle has not been operated before. In step 105, the heat pump is operated in the heating cycle, and the process returns to step 101.

Further, if the cooling flag is 1 in step 104, it has been operated in the cooling cycle before. Therefore, if the selected operation is continued in the heating cycle, the front window may be fogged. Therefore, in step 106, the heat pump cycle is turned off to prohibit switching to the heating cycle, and in step 107, the presence / absence of dew condensation is predicted and calculated based on the vehicle interior temperature, the vehicle exterior temperature, and the humidity. In step 108, as a result of the above calculation,
If the occurrence of dew condensation is not predicted, the prohibition is released and the heat pump is operated in the heating cycle in step 105. If condensation is predicted to occur in step 108, the auxiliary heater 10 is turned on in step 109 while the switching to the heating cycle is prohibited, and the process returns to step 107.

In the cooling cycle operation in step 102 and the heating cycle operation in step 105, the air conditioner control device 18 sets the target outlet temperature according to the set temperature input by the temperature setting device 20 and various internal and external conditions such as the inside and outside air temperatures. After calculating, the blower 9 is controlled via the blower air volume control device 15 so that the air volume set by the blower air volume setting device 14 is reached, and the damper 12a is set so as to enter the air blowing mode set by the air blowing mode setting device 17. .About.12d are driven to open and close the outlets 13a to 13d, the heat pump is switched to the selected cycle by the four-way valve 1, and the drive of the compressor 2 is controlled so that the target outlet temperature is obtained.

In the cooling cycle, the indoor heat exchanger 3 operates as an evaporator and cools air by absorbing heat by the heat exchange medium, so that condensed water in the air adheres to the outer surfaces of the flat tubes and fins. To do. Further, in the heating cycle, the indoor heat exchanger 3 operates as a condenser, and the heat exchange medium radiates heat to heat the air. Therefore, if the heating mode is selected during or after the cooling cycle operation, the condensed water adhering to the indoor heat exchanger 3 is rapidly heated by the cooling cycle operation and is blown into the vehicle, which may cause the front window to become cloudy. There is However, in the above-described embodiment, since the switching from the cooling cycle to the heating cycle is prohibited, the condensed water adhering to the in-vehicle heat exchanger 3 does not evaporate and blow out into the vehicle during the cooling operation. Fogging is prevented. Such prohibition of switching to heating goes against the intention of the occupant who has selected the heating mode.
Is turned on and heating is performed for a time, so that the occupant's discomfort can be minimized.

The condensed water attached to the heat exchanger 3 on the inside of the vehicle during the cooling cycle operation naturally evaporates while the heating is prohibited. Therefore, the humidity sensor 3 provided in the heat exchanger 3 inside the vehicle
The humidity detected by a decreases, and eventually the air conditioner control device 1
When the occurrence of dew condensation is not predicted as a result of the calculation by 8, the prohibition of switching to heating is released and the heating cycle is started.

[0024]

As is apparent from the above description, according to the invention of claim 1, the heating operation is prohibited until it is predicted that no dew condensation will occur when switching from cooling to heating. Fogging of the window due to condensed water adhering to the exchanger is prevented.

According to the second aspect of the present invention, the heating operation is prohibited and the auxiliary heater is turned on until it is predicted that no condensation will occur when the cooling mode is switched to the heating mode. It is possible to prevent fogging of the window due to condensed water adhering to the heat exchanger and to secure a temporary heating by the auxiliary heater, so that discomfort of the occupant is minimized.

[Brief description of drawings]

FIG. 1 is a schematic diagram of an air conditioner for an electric vehicle according to an embodiment.

FIG. 2 is a flowchart of an air conditioning operation.

[Explanation of symbols]

3 ... Heat exchanger inside the vehicle, 3a ... Humidity sensor, 5a ... Outside air sensor, 8a ... Inside air sensor, 10 ... Auxiliary heater, 18 ... Air conditioner control device (air conditioner control means and calculation means), 19
... Mode selection device.

 ─────────────────────────────────────────────────── ─── Continuation of the front page (72) Hideaki Nishii Inventor Hideaki Nishii 5658 Yoshikawa, Hachihonmatsu-cho, Higashihiroshima City, Hiroshima Prefecture Japan Climate Systems Co., Ltd.

Claims (2)

[Claims] 1. A mode selection means for selecting an operation mode of either cooling or heating, and a heat pump cycle capable of operating in a cooling cycle and a heating cycle by switching the refrigerant circulation direction according to the mode selected by the mode selecting means. A heat exchanger inside the vehicle for cooling or heating the air blown into the vehicle, an outside temperature detecting means for detecting the outside temperature of the vehicle, an inside temperature detecting means for detecting the inside temperature of the vehicle, and a heat exchanger passing through the inside of the vehicle. Humidity detection means for detecting the rear air humidity, and whether or not dew condensation has occurred on the front windshield of the vehicle from at least the outside temperature, the inside temperature and the humidity detected by the outside temperature detection means, the inside temperature detection means and the humidity detection means, respectively. And a calculation means for predicting calculation of the above, when the cooling operation mode is switched to the heating operation mode, An air conditioner for an electric vehicle, comprising: an air conditioner control unit that prohibits switching to a heating operation mode until a signal indicating that no dew condensation has occurred is output from the stage. 2. The air conditioner further includes an auxiliary heater that heats blown air in a downstream air flow path of the vehicle interior heat exchanger, and the air conditioner control means is switched from a cooling operation mode to a heating operation mode. At this time, the switching to the heating operation mode is prohibited and the auxiliary heater is turned on until the calculation unit outputs a signal indicating that no dew condensation has occurred, and the auxiliary heater is turned on. apparatus.