JP3295214B2 - Vehicle air-conditioning control method - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a vehicle air-conditioning control method, and more particularly to a vehicle air-conditioning control method capable of performing appropriate air-conditioning control even when its evaporative sensor fails.

[0002]

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

The air conditioning control in such an air conditioner for a vehicle is performed based on an input signal from various sensors such as an outside air sensor and an inside air sensor or an input signal from a target temperature setting means and a rotation angle of the air mix damper. Is controlled, the amount of air blown into the vehicle and the temperature of the air are adjusted, and the inside of the vehicle is set as the target temperature.

In the vehicle air conditioner, if the cooling in the evaporator becomes excessive, the condensed water on the surface of the evaporator freezes and blocks the air flow, so that a desired air volume cannot be obtained in the vehicle. There is a problem. For this reason, by installing an evaporator near 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 the condensed water on the evaporator surface from freezing. I was trying to do it.

[0005]

However, if the evaporator fails, it is impossible to cool down the evaporator until the evaporator is repaired by simply turning off the compressor as described above. There was a problem that appropriate air conditioning control could not be performed. The present invention has been made in view of the above problems, and has as its object to provide a vehicle air conditioning control method capable of appropriately performing air conditioning control even when an evaporator sensor fails.

[0006]

According to the present invention, in order to achieve the above-mentioned object, when cooling or dehumidifying inside air or outside air sucked into a blower unit by an evaporator, detection is performed from an input signal from an evaporator provided in the evaporator. In the vehicle air-conditioning control method in which the compressor is turned on and off in accordance with the degree of freezing and the amount of refrigerant circulating through the evaporator is adjusted, when the evaporator sensor fails, the inside air temperature T _I and the target temperature T _{From the T} and the outside air temperature T _O , the heat load T is given by the following equation: T = (T _I −T _T ) × α + T _O × β α and β are constants, preferably α = 1 to 3 and β = 0.5 to 2. The compressor is turned on and off by estimating the degree of freezing in the evaporator based on the heat load.

The compressor may be controlled to be turned on / off 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 order from an upstream side in a blower unit 1 provided in a front part in 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 rotation 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 that passes through the refrigerant circulating inside by being driven by the compressor 8. The air mix damper 5 is rotated by the drive of the actuator 9, and adjusts a diverting ratio of the air sucked by the sirocco fan 3 according to the rotation position. The heater core 6 is disposed in one of the air passages diverted by the air mix damper 5, and heats the air passing therethrough by circulating engine coolant.

The control device 10 includes an evaporative 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 as target temperature setting means are input. The control device 10 controls the inside / outside air switching damper 2, the air mix damper 5, the compressor 8 based on these input signals.
And the like.

The evaporator sensor 11 is attached to the evaporator 4, and a thermistor or the like whose resistance 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 is converted into a temperature near 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. A thermistor or the like can be used together with the evaluation sensor 11.

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

The control device 10 performs on / off control of the compressor 8 in accordance with the flowchart of FIG. That is, first, in step S1, it is determined whether the evaluation sensor 11 has failed. For example, when the evaluation sensor 11 is disconnected, the detected voltage value is maintained at a constant high value, so that the failure detection can be easily determined based on whether or not the detected voltage value is within a predetermined range. .

If it is determined that the evaluation sensor 11 has not failed, the process proceeds to step S2, and the sensors 12, 13, and 14 and the target temperature setting switch 1 are operated as usual.
The air conditioning control is performed by adjusting the air volume and the air temperature based on the input signal from
OFF control is performed.

The detected voltage value exceeds the predetermined range,
If it is determined that the evaluation sensor 11 has failed, the process proceeds to step S3.
It is determined whether the DEF mode has been selected.
In this DEF mode, the air supplied from the blower unit to the interior of the vehicle is directly removed from the window glass (particularly, the front window) in order to remove fogging of the window glass.
An air outlet that can be sprayed is opened.

Accordingly, 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
It is determined that it is necessary to dehumidify in step S5, and in step S5, the compressor 8 is turned on / off as follows.

That is, based on the target temperature T _T inputted 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, the heat load T is calculated by the following equation. = (T _I -T _T ) × α + T _O × β (α and β are constants). In this case, in terms of comfort, α = 1 to
3, β = 0.5 to 2 is preferred, 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 (T _ON / T _OFF when the _ON time T _ON and the OFF time T _OFF are assumed to be 8/45) with respect to the change amount of the heat load, that is, the heat load The on / off ratio was changed from 1/3 to 3 while the temperature changed by 15 ° C.
What is necessary is just to make it change in the 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. according to the above equation. Then, based on the heat load of 40 ° C., the compressor 8
On / off control is performed in a cycle of 80 seconds, which is on for 0 seconds and off for 20 seconds.

As described above, in step S5, although the evaporator sensor 11 is out of order, the compressor 8
When ON / OFF control is performed, since the frozen state in the evaporator 4 is not directly detected by the evaporator 11 but is estimated by the heat load, a warning is displayed in step S6 and a warning is displayed to the occupant. Alerts you by informing.

If the DEF mode has not been selected in step S3, the compressor 8 is kept off in step S4. This is because, in modes other than the DEF mode, the supply air into the vehicle is not directly blown onto the window glass. Therefore, even when the compressor 8 is off and the dehumidification is not performed by the evaporator 4, the occurrence of clouding is a serious problem. It is because it does not become.

As described above, since the on / off control of the compressor 8 can be performed based on the heat load, even if the evaporator 11 is out of order, the evaporator 4 cools the passing air while preventing freezing. It is possible to dehumidify and 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. However, the on / off ratio may be determined based on only one of the outside air temperature and the inside air temperature. . However, if it is based on the outside air temperature, it is necessary to switch to the outside air introduction mode, and if it is based on the inside air temperature, it is necessary to switch to the inside air circulation mode.

In the above-described embodiment, the control for forcibly turning on the compressor 8 is performed when the DEF mode is selected. However, 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 if the evaporator sensor fails, the frozen state of the evaporator can be estimated based on the heat load obtained by calculation. To turn on the compressor
Since the off control can be performed, cooling and dehumidification of the passing air can be performed while preventing freezing in the evaporator, and appropriate air conditioning control can be performed.

If the compressor is controlled to be turned on / off only when the DEF mode is selected, the cooling by the evaporator is stopped and the freezing is effectively performed in a state where fogging is not easily generated in the window glass. Can be prevented.

[Brief description of the drawings]

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

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

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

[Explanation of symbols]

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

──────────────────────────────────────────────────続 き Continuing from the front page (72) Inventor Yasufumi Kurahashi 5658 Yoshikawa, Oazahonmachi-cho, Higashihiroshima-shi, Hiroshima Inside Japan Climate Systems Corporation (72) Inventor Hiroshi Kondo 5658 Yoshikawa, Hachimotomatsu-cho, Higashihiroshima-shi, Hiroshima Japan Climate Systems Inc. (72) Inventor Hideaki Nishii Hiroshima Prefecture, Hiroshima Prefecture, Hachihonmatsu-cho, Ogawa 5658 No. 5650 Yoshikawa Tanaka, Higashihiroshima City, Hiroshima Pref. Japan Climate Systems Corporation (56) References JP-A-4-372420 (JP, A) JP-A-5-16655 (JP, A) JP-A-57-147906 (JP, A) JP-A-57-147906 166437 (JP, A) JP-A-2-57422 (JP, A) JP-A-60-128018 (JP, A) 08 (JP, U) Fully open sho 59-139415 (JP, U) Fully open sho 55-37729 (JP, U) (58) Fields investigated (Int. Cl. ⁷ , DB name) B60H 1/32 F25B 1 / 00 F25B 47/02 F25B 49/02 B60H 1/00 B60H 3/00

Claims (2)

(57) [Claims] When cooling or dehumidifying inside air or outside air sucked into a blower unit by an evaporator, on / off control of a compressor is performed according to a degree of freezing detected from an input signal from an evaporator provided in the evaporator. In the air conditioning control method for a vehicle in which the amount of refrigerant circulating in the evaporator is adjusted, 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 according} to the following equation: (T _I -T _T ) × α + _TO × β (α and β are constants), and controlling the compressor on / off by estimating the degree of freezing in the evaporator based on the heat load. An air conditioning control method for a vehicle, comprising: 2. The air conditioning control method for a vehicle according to claim 1, wherein the on / off control of the compressor is performed only when the DEF mode is selected.