JPH0125692Y2 - - Google Patents

Description

[Detailed Description of the Invention] [Industrial Application Field] The present invention relates to a vehicle air conditioning system, and particularly to a vehicle air conditioning system that compensates for a failure of a defrost mode switching actuator.

[Conventional technology]

Conventionally, a vehicle air conditioner has, as shown in FIG. 5, an inside/outside air switching door 2 provided in a duct 1, a blower 3, a cooler 4, an air mix door 5,
Heater 6, mode switching doors 7, 8, defrost outlet 9, face outlet 10, foot outlet 1
1. Here, the cooler 4 includes a compressor 12, a condenser 13, and a receiver tank 1.
4, an expansion valve 15 constitutes a cooling cycle, and the engine 1 is connected to the compressor 12.
6 is transmitted through the magnetic clutch 17.

The inside/outside air switching door 2 includes an inside/outside air switching circuit 20,
The blower 3 is controlled by a blower rotation speed control switch 24 via a blower control circuit 23, and the cooling cycle is controlled by an air conditioner control circuit 25 via a compressor control circuit 25. The air mix door 5 is controlled by the operation switch section 26, and the air mix door 5 is controlled by the air mix door operating section 2 via the air mix door drive circuit 27 and the actuator 28.
The mode switching doors 7 and 8 are controlled by a mode control circuit 30, an actuator 31, and
32 and is controlled by the mode changeover switch section 31.

[Problem that the invention attempts to solve]

However, conventional vehicle air conditioners
As disclosed in JP-A-58-128918, if the defrost mode switching actuator fails, the drive power for the actuator is simply turned off by a thermal fuse or other means, and if the actuator fails, the defrost function will not function at all. I lose it. Therefore, if the defrost mode switching actuator does not operate while the vehicle is running, the window glass becomes cloudy and the vehicle becomes unable to drive.

[Means for solving problems]

In the present invention, when the defrost mode switching actuator fails, the failure compensation means sets the inside/outside air switching door to the outside air introduction mode, increases the speed of the blower, or operates the compressor according to the outside temperature.

This compensates for the defrost function.

[Effect]

When the detection means detects that the defrost switch is on and the defrost mode switching actuator is malfunctioning, the failure compensation means switches the inside/outside air switching door to the outside air introduction mode according to the output (outside air temperature) of the outside air temperature sensor. Increase the speed of the blower or turn on the compressor.

〔Example〕

FIG. 1 is a simplified configuration diagram showing an embodiment of a vehicle air conditioner according to the present invention, and the same parts as in FIG. 5 are denoted by the same reference numerals.

In the figure, reference numeral 40 indicates failure detection means for detecting a failure of the drive motor (not shown) of the defrost mode switching actuator 32 due to any cause, and 41 indicates the on/off state of the defrost switch in the mode selection switch section 31. The on/off detection means 42 uses outputs from both of these detection means to set the inside/outside air switching door 2 to the outside air introduction mode when the outside air temperature detected by the outside air temperature sensor 43 is lower than a set value, for example, 5°C. It outputs a signal to the inside/outside air switching circuit 20 and also sends a signal to the blower control circuit 2 to increase the speed of the blower 3.
3, and outputs a signal to the compressor control circuit 25 to turn on the compressor 12 of the cooler 4 when the outside air temperature is higher than the set value.

Here, the specific configuration of both the detection means 40 and 41 will be explained using FIG. 2. In this figure, the same reference numerals as in Figure 1 indicate the same parts, and 50
is a servo motor for driving the defrost mode switching actuator, 51 is a drive circuit for driving and controlling this motor 50, 52 to 54 are mode switching switch sections, and 55 is a detection resistor connected in series to the servo motor 50. .

Now, when the defrost switch 52 of the mode changeover switch section is turned on, the on/off detection means 41 detects the current flowing through the line of the defrost switch 52 and outputs a signal indicating that the switch 52 is on. On the other hand, at the same time, the drive circuit 51 operates to flow the drive current i to the servo motor 50. At this time, if the motor 50 fails and does not rotate, a large drive current i flows, so the failure detection means 40 detects this as the voltage Vout between the terminals of the detection resistor 55.
detects the defrost mode switching actuator and outputs a signal indicating that the defrost mode switching actuator is malfunctioning.
FIG. 3 shows the relationship between the drive current i and the terminal voltage Vout.

Next, the operation of the failure compensating means 42 will be explained using the flowchart shown in FIG. If the defrost switch is off based on the output from the on/off detection means 40, the step does not proceed and the failure compensation means does not output any output. On the other hand, if it is on, the process proceeds to the next step and the output from the failure detection means 40 is determined. As a result, if there is no failure (NO),
Defrost mode can be obtained normally. If there is a failure (YES), the process proceeds to the next step and is divided into two processes depending on the output from the outside temperature sensor 43. That is, when the outside air temperature is less than 5° C., the failure compensation means 42 outputs a signal to the outside air switching circuit 20 to set the outside air introduction mode, and also outputs a signal to the blower control circuit 23 to increase the speed of the blower 3. Output.

On the other hand, when the outside temperature is 5℃ or higher, the cooler 4
A signal to turn on the compressor 12 is output to the compressor control circuit 25.

In this embodiment, although the outside air introduction mode and the speed increase of the blower are made to compete with each other, it is also possible to selectively perform only one of the operations.

〔effect〕

As explained above, according to the present invention, if the defrost mode actuator fails, the defrost function is compensated for by other means, so that fogging prevention can be performed at all times, contributing to safe driving and accident prevention. do. Furthermore, even people who do not know how to operate an air conditioner can prevent fogging.

[Brief explanation of drawings]

FIG. 1 is a simplified configuration diagram showing an embodiment of a vehicle air conditioner according to the present invention, FIG. 2 is a circuit diagram showing the main parts of the embodiment, and FIG. 3 is a graph showing the operation of the embodiment. FIG. 4 is a flowchart showing the operation of the same embodiment, and FIG. 5 is a simplified configuration diagram showing the conventional example. 40...Failure detection means, 41...On/off detection means, 42...Failure compensation means, 43...Outside air temperature sensor.

Claims (1)

[Scope of utility model registration request] In a vehicle air conditioner equipped with a cooler that cools air introduced by a blower from the outside air switching door side, an air mix door that adjusts the mixing ratio of warm air and cold air, and a mode switching door, the outside air temperature A sensor, a defrost mode switching actuator failure detection means, a defrost switch on/off detection means, and the outputs of both of these detection means determine that when the outside air temperature detected by the outside air temperature sensor is lower than a set value, the inside/outside air switching door is activated. An air conditioner for a vehicle, characterized in that it is provided with a failure compensating means for setting the air conditioner to outside air introduction mode or increasing the speed of the blower and turning on the compressor of the cooler when the speed is higher than a set value.