JPH07215048A - Air conditioning control method for vehicle - Google Patents

Abstract

PURPOSE:To appropriately perform air conditioning in an air conditioner for vehicle in which a refrigerant quantity is adjusted according to the degree of freezing detected with an evaporation sensor by computing a thermal load from inner temperature, target temperature, and open air temperature by the use of a specified formula, even if a trouble is generated in the evaporation sensor, and estimating the degree of freezing. CONSTITUTION:An evaporator 4 cools and dehumidifies passing air by gasifying refrigerant circulated in the interior by driving a compressor 8. A control device 10 controls to drive a changeover damper 2, an air mix damper, and a compressor 8 based on the detected values of an evaporation sensor 11, an open air sensor 12, an inner air sensor 13, and a solar radiation sensor 14, and the input signal value from a target temperature setting switch 15. When the detected values exceed prescribed ranges and the trouble of the evaporation sensor 11 is judged, from the target temperature TT input from the target temperature setting switch 15, the inner air temperature T1 and the open air temperature T0, a thermal load T is computed by the equation T=(T1-TT)Xalpha+T0Xbeta(alpha or beta is constant), and hence the degree of freezing is estimated.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a vehicular air conditioning control method, and more particularly to a vehicular air conditioning control method capable of performing an appropriate air conditioning control even if the evaluation sensor fails.

[0002]

2. Description of the Related Art Conventionally, in an air conditioner for a vehicle, inside air or outside air sucked into a blower unit by a sirocco fan is cooled and dehumidified by an evaporator and then divided by an air mix damper, and then one is heated as it is and the other is heated by a heater core. Then, the two are mixed to adjust the temperature to a predetermined temperature, and the air is blown into the vehicle.

Air-conditioning control in such a vehicle air-conditioning system is carried out based on input signals from various sensors such as an outside air sensor, an inside air sensor or target temperature setting means, and the rotation speed of the sirocco fan and the rotation angle of the air mix damper. Is controlled to adjust the amount of air blown into the vehicle and the temperature of the air blow so that the inside of the vehicle becomes the target temperature.

In the vehicle air conditioner, when the evaporator cools excessively, the condensed water on the evaporator surface freezes and hinders air flow, so that a desired air flow cannot be obtained in the vehicle. There is a problem. Therefore, by attaching an evaporator sensor in the vicinity of the evaporator, when the detected temperature drops below a predetermined value, the compressor is turned off to stop the circulation of the refrigerant, thereby preventing freezing of condensed water on the evaporator surface. I was trying to do it.

[0005]

However, if the evaporator sensor fails, as described above, the evaporator cannot be cooled until the evaporator sensor is repaired by simply turning off the compressor. There was a problem that proper air conditioning control could not be performed. In view of the above problems, it is an object of the present invention to provide a vehicle air conditioning control method capable of appropriately performing air conditioning control even when the EVA sensor fails.

[0006]

Means for Solving the Problems In order to achieve the above object, the present invention detects, from an input signal from an evaporator sensor provided in an evaporator when cooling or dehumidifying the inside air or the outside air sucked in a blower unit by the evaporator. In a vehicle air conditioning control method in which the compressor is controlled to be turned on / off in accordance with the degree of freezing, and the amount of refrigerant circulating to the evaporator is adjusted, if the evaporation sensor fails, the inside air temperature T _I and the target temperature T _The thermal load T is calculated from _T and the outside air temperature T _{O as} follows: T = (T _I −T _T ) × α + T _O × β α, β are constants, and α = 1 to 3 and β = 0.5 to 2 are preferable. According to the heat load, the compressor is turned on and off by estimating the degree of freezing in the evaporator based on the heat load.

Further, when the evaporator sensor has failed, the freezing degree in the evaporator is estimated based on the outside air temperature when the outside air introduction mode is selected and the inside air temperature when the inside air circulation mode is selected. By doing so, the compressor may be on / off controlled. Further, the compressor may be on / off controlled only when the DEF mode is selected.

[0008]

Embodiments of the present invention will be described below with reference to the accompanying drawings. As shown in FIG. 1, an inside / outside air switching damper 2, a sirocco fan 3, an evaporator 4, an air mix damper 5, and a heater core 6 are arranged in this order from the upstream side in the blower unit 1 provided in the front part of the vehicle. ing.

The inside / outside air switching damper 2 adjusts the suction amount of the inside air or the outside air depending on the rotating position. The sirocco fan 3 is rotated by a sirocco fan motor 7 and sucks inside air or outside air into the blower unit 1. The evaporator 4 cools and dehumidifies the air passing through the inside of which the refrigerant circulating therein is vaporized by driving the compressor 8. The air mix damper 5 is rotated by driving the actuator 9, and adjusts a shunting ratio of the air sucked by the sirocco fan 3 depending on a rotation position. The heater core 6 is disposed in one of the air passages divided by the air mix damper 5, and heats the air passing by the engine cooling water circulating therein.

Further, the control device 10 includes an evaluation sensor 11,
Detection signals from the outside air sensor 12, the inside air sensor 13, and the solar radiation sensor 14 and an input signal from a target temperature setting switch 15 which is a target temperature setting means are input. The control device 10 controls the inside / outside air switching damper 2, the air mix damper 5, and the compressor 8 based on these input signals.
Drive control.

The evaporation sensor 11 is attached to the evaporator 4, and a thermistor whose resistance value changes according to the ambient temperature can be used. The change in the resistance value is detected as a voltage value by the control device 10 and converted into a temperature in the vicinity of the evaporator 4.

The outside air sensor 12 is provided in the front part of the vehicle, and the inside air sensor 13 is provided in the instrument panel in the front part of the vehicle. As with the evaluation sensor 11, both thermistors and the like can be used.

The solar radiation sensor 14 is provided on a dashboard in the front of the vehicle, and a photodiode or the like whose current value changes according to the amount of solar radiation can be used. This change in current value is converted into the amount of solar radiation by the control device 10.

The control device 10 controls ON / OFF of the compressor 8 according to the flow chart of FIG. That is, first, in step S1, it is determined whether or not the evaporation sensor 11 is out of order. For example, when the evaluation sensor 11 is disconnected, the detected voltage value is maintained at a constant high value, so that failure detection can be easily determined by whether the detected voltage value is within a predetermined range. .

If it is determined that the evaporation sensor 11 is not in failure, the process proceeds to step S2, and the sensors 12, 13, 14 and the target temperature setting switch 1 are operated as usual.
Based on the input signal from 5, the air flow rate and air temperature are adjusted to control the air conditioning, and the compressor 8 is turned on.
Performs off control.

Further, the detected voltage value exceeds the predetermined range,
If it is determined that the evaporation sensor 11 has failed, step S3
Then, it is determined whether or not the DEF mode is selected.
In this DEF mode, the air supplied from the blower unit into the vehicle directly removes the fog on the window glass (especially the front window).
A blower opening that can be blown to the inside opens.

Therefore, if it is determined in step S3 that the DEF mode has been selected, it is in a state where clouding on the window glass is likely to occur, and the evaporator 4
In step S5, the compressor 8 is controlled to be turned on / off as follows.

That is, the heat load T is calculated from the target temperature T _T input from the target temperature setting switch 15, the inside air temperature T _I detected by the inside air sensor 13 and the outside air temperature T _O detected by the outside air sensor 12 by the following equation T = (T _I −T _T ) × α + T _O × β (α and β are constants). In this case, in terms of comfort, α = 1 to 1
3, β = 0.5 to 2 is preferable, and α = 2 and β = 1 are optimal.

The on / off time ratio of the compressor 8 is determined based on the heat load calculated by the above equation according to the graph of FIG. In this graph, the on-off ratio of the compressor 8 with respect to the change amount of the thermal load (on-time T _ON, when the OFF time _{T OFF, T ON / T OFF} ) ratio of 8/45, i.e., the thermal load The on / off ratio was changed from 1/3 to 3 while the temperature changed by 15 ° C.
It may be changed at a ratio of 1.25 / 22.5.

Specifically, when the target temperature is set to 22 ° C., if the outside air temperature is 30 ° C. and the inside air temperature is 27 ° C., the heat load is 40 ° C. from the above equation. Then, based on this heat load of 40 ° C., the compressor 8 is
It is controlled to be turned on and off in a cycle of 80 seconds in which it is turned on for 0 seconds and turned off for 20 seconds.

In this way, in step S5, the compressor 8
When the on / off control is performed, since the frozen state in the evaporator 4 is not directly detected by the evaporation sensor 11 but is estimated by the heat load, a warning display is given to the occupant in step S6. Call attention to them by notifying them.

If the DEF mode is not selected in step S3, the compressor 8 is maintained in the off state in step S4. This is because, except in the DEF mode, the air supplied to the inside of the vehicle is not directly blown to the window glass, so that even if the compressor 8 is in the off state and the evaporator 4 is not dehumidifying, the occurrence of fog is a serious problem. This is because it does not become.

As described above, since the compressor 8 can be controlled to be turned on / off based on the heat load, even if the evaporator sensor 11 is out of order, the evaporator 4 cools the passing air while preventing freezing. It is possible to dehumidify, and it is possible to properly perform air conditioning in the vehicle.

In the above embodiment, the ON / OFF ratio of the compressor 8 is determined based on the heat load, but it may be determined based on either the outside air temperature or the inside air temperature. . However, when it is based on the outside air temperature, it is necessary to switch to the outside air introduction mode, and when it is based on the inside air temperature, it is necessary to switch to the inside air circulation mode.

Further, in the above embodiment, if the DEF mode is selected, the compressor 8 is forcibly turned on, but the air conditioning control may be performed without making this determination. .

[0026]

As is apparent from the above description, according to the vehicle air conditioning control method of the present invention, even when the evaporator sensor fails, the evaporator load is calculated based on the heat load or the inside / outside air temperature obtained by calculation. Since it is possible to control the compressor on / off by estimating the frozen state, it is possible to cool / dehumidify the passing air while preventing freezing in the evaporator, and it is possible to perform appropriate air conditioning control.

Further, if the compressor is controlled to be turned on / off only when the DEF mode is selected, cooling in the evaporator is stopped and freezing is effectively performed in a state where clouding to the window glass is unlikely to occur. Can be prevented.

[Brief description of drawings]

FIG. 1 is a block diagram of a vehicle air conditioner according to this embodiment.

FIG. 2 is a graph showing the relationship between heat load and compressor on / off time.

FIG. 3 is a flowchart showing on / off control of a compressor.

[Explanation of symbols]

4 ... Evaporator, 8 ... Compressor, 10 ... Control device, 11 ... Evaporator.

Front page continued (72) Inventor Hiroshi Kondo 5658 Yoshikawa, Hachimotomatsucho, Higashihiroshima City, Hiroshima Prefecture Japan Climate Systems Co., Ltd. (72) Hideaki Nishii 5658 Yoshikawa, Hachihonmatsucho, Hiroshima Prefecture Hiroshima Japan Inside Climate Systems (72) Inventor Koji No.5658 Yoshikawa, Hachimotomatsucho, Higashihiroshima City, Hiroshima Prefecture Japan Climate Systems Co., Ltd.

Claims (3)

[Claims] 1. When cooling or dehumidifying the inside air or the outside air sucked into the blower unit by an evaporator, the compressor is controlled to be turned on / off according to a freezing degree detected from an input signal from an evaporator sensor provided in the evaporator, In the vehicle air conditioning control method for adjusting the amount of refrigerant circulating to the evaporator, when the evaporator sensor fails, the heat load T is calculated from the inside air temperature T _I , the target temperature T _T, and the outside air temperature T _O by the following equation T = (T _I −T _T ) × α + _TO × β (α and β are constants), and on / off control of the compressor is performed by estimating the freezing degree in the evaporator based on the heat load. An air conditioning control method for a vehicle, comprising: 2. When the inside air or the outside air sucked into the blower unit is cooled and dehumidified by an evaporator, the compressor is controlled to be turned on and off according to a freezing degree detected from an input signal from an evaporator sensor provided in the evaporator, In a vehicle air conditioning control method adapted to adjust the amount of refrigerant circulating to the evaporator, in the case where the evaporator sensor has failed, when the outside air introduction mode is selected, the outside air temperature and the inside air circulation mode are selected. In the vehicle air conditioning control method, the compressor is controlled to be turned on and off by estimating a freezing degree in the evaporator based on an inside air temperature. 3. The vehicle air conditioning control method according to claim 1, wherein the compressor is on / off controlled only when the DEF mode is selected.