JPS6241126B2 - - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION The present invention relates to an air conditioner for a vehicle, and more particularly to an air conditioner that prevents unnecessary fluctuations in the opening degree of an air mix door.

Conventionally, an automatic air conditioner has an evaporator 1 installed on the upstream side and a heater core 2 on the downstream side, as shown in FIG. 1. The evaporator 1 has the function of cooling incoming air. Compressor 3, condenser 6, receiver 7
and an expansion valve 8 constitute a cooling cycle, which is driven by turning on and off the electromagnetic clutch 4 of the compressor 3, and its drive is controlled by the output from the control circuit 5. .

The heater core 2 has the function of warming the incoming air, and the heating temperature is controlled by opening and closing the water tap 9, and the supply of air is controlled by the actuator 11 for controlling the air mix door 10. Actuator 11 is controlled by control circuit 5 . That is, the air mix door 10 is provided upstream of the heater core 2, and the temperature is appropriately controlled by changing the mixing ratio of cold air and hot air depending on the opening degree of the air mix door 10.

The blower 12 selectively sucks outside air or inside air from an outside air port 13 or an inside air port 14 depending on the position of the inside/outside air switching door 15, and sends it to the evaporator 1.

The rotation speed of the blower 12 is sequentially controlled from stop to maximum rotation by the output from the control circuit 5. The inside/outside air switching door 15 is controlled by the output of the control circuit 5 via the actuator 16. The most downstream part of this device is branched into an upper outlet 17 and an outlet 18, and the outlet 18 is further branched into a defrost outlet ₁₈₁ and _a lower outlet 182. A door 19 for mode switching is provided at the branching point of the air outlet 18, and a door 20 for mode switching is provided at the air outlet 18. The door 19 is controlled by an actuator 22, and the door 20 is similarly controlled by an actuator 23. .

In the above configuration, conventionally, the outside air temperature is detected and when the outside air temperature becomes lower than a predetermined temperature, the compressor 3 is turned off and some outside air is introduced in order to save power. According to this, based on the introduction of outside air, the evaporator 1
Since the air temperature on the downstream side of the evaporator 1 changes more rapidly than when the compressor 3 is turned on, and the blowout temperature fluctuates, a temperature sensor 30 is installed downstream of the evaporator 1 to prevent this from happening. The degree is corrected.

However, according to the above configuration, a temperature sensor for freezing prevention is installed in the evaporator 1, and the compressor 3 is turned on and off by this temperature sensor to prevent the evaporator 1 from freezing. Since the temperature applied to the mixer door 30 fluctuates wildly, the mixer door 10, which is compensated for by this, is constantly moved, and the mixer door 10
The mechanism that drives this is likely to become fatigued, and the temperature of the blown air will also fluctuate.

The object of the present invention is to locate a temperature sensor upstream of the evaporator, to connect this temperature sensor to the mix door control circuit in the compressor non-operation mode, and to connect a fixed resistor for adjusting the opening of the mix door in the compressor operation mode. By connecting to the mix door control circuit, the opening degree of the mix door can always be corrected, and the swing of the mix door is prevented, thereby eliminating the above drawbacks. .

FIG. 2 is a circuit diagram showing an embodiment of the vehicle air conditioner according to the present invention, and the same parts as in FIG. 1 are designated by the same reference numerals. In the figure, 40 is a temperature sensor located upstream of the evaporator 1, and one end of this is a movable contact 31 with a switching contact _31.
and the other end is grounded. Fixed contact 31 ₂
is connected to the fixed contact ₃₂₁ of the switching point 32, and the fixed contact ₃₁₃ is connected to the compressor control circuit 33, and the contact ₃₃₁ , which is turned on by the output of this circuit 33, is used to drive the electromagnetic clutch control contact ₃₄₁ . Connected to relay 34. One fixed contact ₃₂₂ of the switching contact 32 is grounded via a fixed resistor 35, and this movable contact ₃₂₃ is connected to the control circuit 5 via a solar radiation sensor 36, an outside air sensor 37, and an inside air sensor 38.
The output of the mix door control circuit 5 is
It is supplied to the actuator 11. Note that the actuator 11 is feedback-controlled by a position detector 39. The compressor control circuit 33 includes a temperature sensor 41 for detecting the temperature of the evaporator 1.
is connected to the evaporator 1, which is installed close to the evaporator 1. Further, 45 is a variable resistor serving as a room temperature setting section.

The compressor control circuit 33 includes a sensor 40,
When the temperature t of the air _introduced into the evaporator 1 is higher than the predetermined temperature _t1 as shown in FIG. When the temperature of the introduced air is lower than a predetermined temperature _t1 , the compressor is controlled to be turned off when the temperature P of the evaporator 1 is higher than _P1 , thereby preventing freezing. In addition, the compressor 3 is controlled based on the temperature of the introduced air, thereby eliminating unnecessary operations of the compressor 3.

This compressor control circuit 33 includes, for example, a fourth
As shown in the figure, it has a comparator 33b that compares the temperature P of the air introduced into the evaporator side taken in by the temperature sensor 40 and the off level signal l from the off level setting device 33a. When P decreases and reaches the off level signal l, the relay 33c is turned off. here,
If the contact 331 is configured to turn off when the relay _33c is deenergized, the temperature P of the evaporator will not fall below the off level signal l. in this case,
In this embodiment, as the temperature t of the air introduced into the evaporator side taken in by the temperature sensor 40 increases, the off-level signal l gradually decreases in accordance with the characteristics shown in FIG. 3, and then saturates to a low level. By configuring the off-level setter 33a in the above-mentioned manner, efficient operation rate control of the compressor can be performed based on the temperature P of the introduced air, as described above.

Here, the resistance value of the fixed resistor 35 is determined by the temperature sensor 3, which is conventionally used for correcting the opening degree of the air mix door.
It is set to the average value of the resistance value of 0. That is, the resistance value corresponds to the average temperature on the downstream side of the evaporator 1 when the compressor 3 is turned on. Note that each of the switching contacts 31 and 32 is controlled by a relay ₃₁ that is controlled by a signal from an operating mode detector of the compressor 3.

In the above structure, when the compressor 3 is off, the movable contacts 31 ₁ , 32 of the switching contacts 31, 32
₃ is the state shown by the solid line, the temperature sensor 40 detects the inside and outside air from the blower 12, and sends its output along with the sensors 36, 37, and 38 to the control circuit 5 for driving the actuator, thereby turning off the compressor 3. At times, the opening degree of the mixer door 10 is corrected to prevent differences in blowout temperature. next,
When the compressor 3 is on, the relay ₃₁ is activated, the switching contacts 31 and 32 are switched, and the temperature sensor 40 is switched on.
sends an output to the compressor control circuit 33.
Furthermore, a fixed resistor 35 for correcting the opening of the mixer door is connected to the circuits of the sensors 36, 37, and 38.
The opening degree of the mixer door when the switch is on is corrected.

The compressor control circuit 33 also includes a sensor 4.
Since a signal is sent from terminals 0 and 41, this controls the contact _33-1 to prevent the evaporator 1 from freezing, and also sets the off level at which the contact _33-1 turns off as the temperature of the air introduced into the evaporator 1 decreases. is increased to increase the rate at which the compressor 3 stops, thereby preventing wasteful operation of the compressor 3.

In other words, conventionally, the temperature sensor 30 immediately after the evaporator and the anti-freeze sensor are provided for control, which has the disadvantage that the opening degree of the mix door 10 changes unnecessarily, but according to this embodiment, the compressor When the compressor 3 is on, a fixed resistor 35 whose resistance value remains unchanged is connected to the control circuit 5, and when the compressor 3 is off, a sensor 4 that detects the temperature of the air introduced into the evaporator 1 is connected.
0 is connected, even if the compressor 3 is turned off due to a drop in the outside air temperature and outside air is introduced, the opening degree of the mix door 10 will be adjusted according to the difference in resistance value between the resistor 35 and the sensor 40. Correction is added to reduce the level difference in the blowout temperature due to the introduction of outside air, and it can perform almost the same function as the conventional temperature sensor 30, and the compressor 3 is connected to the control circuit 3.
Even if it is turned on and off by the output 3, there is almost no change in the resistance of the resistor 35 and sensor 40, so the mix door does not swing, reducing fatigue of the mix door drive mechanism and reducing the difference in air blowing temperature. can. In addition, the off level of the compressor 3, which is controlled based on the temperature of the evaporator 1, is controlled by the temperature of the air introduced into the evaporator 1 in the operating mode of the compressor 3, so the operation of the compressor 3 is not necessary. Since it can be kept to a minimum, it is possible to save power.

As explained above, according to the present invention, a temperature sensor for detecting the temperature of the air introduced into the evaporator is connected to the input side of the control circuit of the air mixer in the non-operating mode of the compressor, and A fixed resistor with a predetermined resistance value was connected to the side to correct the opening degree of the air mix door, so
The opening degree of the air mix door can be corrected without causing the air mix door to swing, and power can be saved by using the temperature sensor when the compressor is in the operating mode to adjust the off level of the compressor.

[Brief explanation of the drawing]

FIG. 1 is a simplified configuration diagram showing an example of a conventional vehicle air conditioner, FIG. 2 is a circuit diagram showing an embodiment of the vehicle air conditioner according to the present invention, and FIG. 3 is an operating characteristic of a compressor control circuit. FIG. 4 is a circuit diagram showing a specific example of the compressor control circuit 33. 3... Compressor, 5... Control circuit, 10...
... Air mix door, 33 ... Compressor control circuit, 32, 33 ... Switching contact, 35 ... Fixed resistance, 36, 37, 38 ... Sensor, 40, 41 ...
...Temperature sensor.

Claims (1)

[Claims] 1. An air mix door that adjusts the mixing ratio of cold air from the cooler and warm air from the heater, and a mix door control circuit that controls the opening degree of the air mix door by comparing the inside temperature, the outside temperature, and a signal from a room temperature setting section;
In a vehicle air conditioner, the air conditioner has a compressor control circuit that turns off the compressor when the temperature detected by the cooler temperature sensor 41 reaches a predetermined off level in the operating mode of the compressor. A sensor 40 is provided, the temperature sensor 40 is connected to the input side of the mix door control circuit in the non-operating mode of the compressor, and a fixed resistor having a predetermined resistance value is connected to the input side of the mix door control circuit in the operating mode of the compressor. At the same time, the temperature sensor 40 is connected to the input side of the compressor control circuit, and as the temperature of the air introduced into the cooler side detected by the temperature sensor 40 becomes lower, the compressor control circuit An air conditioner for a vehicle, characterized in that the off level is raised to reduce the operating rate of a compressor.