JPS5939335B2 - Vehicle air conditioner - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION The present invention prevents unnecessary fluctuations in the opening degree of a vehicle air conditioner, particularly an air mix door, and also prevents unnecessary fluctuations in the opening degree of a vehicle air conditioner, and when dehumidifying by driving a compressor when the outside air temperature is relatively low. The present invention relates to an air conditioner configured to switch the operating temperature setting of a compressor to a lower limit.

Conventionally, a vehicle air conditioner has an evaporator 1 installed on the upstream side and a heater core 2 installed on the downstream side, as shown in FIG. 1, compressor 3,
A cooling cycle is constituted by a condenser 6, a liquid receiver 7, and an expansion valve 8, and its drive is performed by turning on and off the electromagnetic clutch 4 of the compressor 3, and its drive is controlled by a control circuit 5. This is done by output.

The heater core 2 has the function of warming the incoming air, and the heating temperature is controlled by opening and closing the water cock 9, and the supply of air is controlled by the actuator 11 for controlling the air mix door 10.

The actuator 11 is controlled by a 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 draws outside air or inside air from the outside air port 13 or the inside air port 14 depending on the position of the inside/outside air switching door 15;
Send to evaporator 1.

The inside/outside air switching door 15 is controlled by an actuator 16.

The most downstream side of this device is the lower air outlet 17 and the air outlet 1.
The air outlet 18 is further branched into a defrost air outlet 18 and a lower air outlet 18□, and the air outlet 18 is further branched into a defrost air outlet 18 and a lower air outlet 18
A door 19 for mode switching is provided at the branching point between and 18, and a door 20 for mode switching is provided at the air outlet 18.
0 is similarly controlled by 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 at which the compressor does not need to be operated, the compressor 3 is turned off to save power. Due to this, the air temperature downstream of the evaporator 1 changes more rapidly than when the compressor 3 is turned on, and the blowout temperature fluctuates.In order to prevent this, a temperature sensor 3 is installed downstream of the evaporator 1.
A mode sensor is provided to detect temperature changes and correct the opening degree of the mix door.

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. 30
Since the temperature applied to the mix door fluctuates drastically, the mix door 10 to be corrected is constantly moved, which tends to fatigue the mechanism driving the mix door 10, and also causes the temperature of the blown air to fluctuate.

An object of the present invention is to provide an air conditioner in which the output of an input signal calculation section is sent to at least a control section for controlling an air mix door and a control section for controlling a compressor, in which a temperature sensor is provided downstream of a blower; This temperature sensor is connected to the input signal calculation section in the compressor non-operation mode setting, and a fixed resistor for adjusting the opening of the mix door is connected to the input signal calculation section in the compressor operation mode setting, so that the mix door is always connected to the input signal calculation section. The opening degree of the mix door can be corrected, and swinging of the mix door is prevented.
This eliminates the above drawbacks.

Furthermore, a temperature switch is provided which operates below a predetermined outside air temperature, so that when dehumidification operation is required, the operating temperature setting of the compressor control section is switched to the lower limit to enable the compressor to be driven.

This will be explained in detail below using examples.

FIG. 2 is a circuit diagram showing an embodiment of the vehicle air conditioner according to the present invention.
1□ to the electromagnetic clutch 4, and the relay 41 is connected to the compressor on mode switch 40 via a protection switch 42 and a contact 43, which are turned on when the outside temperature drops to near 0°C.

The contact 43 is controlled by the compressor control section 43.

A relay 46 that controls a switching contact 45 and a compressor control unit 43 is also connected to the switch 40 via a thermostat (outside air temperature detection switch) 44, and a movable contact 45□ of the switching contact 45 controlled by this relay 46 is connected to the input side of the input signal calculation unit 47, its fixed contact 452 is provided with a fixed resistor 48 that constitutes the air mix door opening correction resistance unit 55, and its fixed contact 453 is provided on the downstream side of the evaporator 1. A mode sensor 49 is connected.

The input signal calculation unit 47 compares and processes the output from the switching contact 45 with the outputs from the vehicle interior temperature setting variable resistor 50, the inside air sensor 51, and the outside air sensor 52, and performs calculation processing on the control unit 53 for controlling the air mix door and the compressor. control unit 43 for
sends a signal to

The compressor control section 43 controls the contact point 4 based on the output of the input signal calculation section 47, the operating state of the relay 46, and the signal of the temperature sensor 54 for detecting the surface temperature of the evaporator 1.
3. Drive.

The thermostat 44 is driven by an outside air switch 56 that detects a signal from an outside air sensor 55. For example, when the outside air temperature is 17 to 20 degrees Celsius or higher, the thermostat 44 is turned on and 17 to 20 degrees Celsius is turned on.
It is controlled so that it is turned off (see FIG. 3) in the following cases.

By operating the relay 46 based on this off state, the compressor control unit 43 lowers the comparison level at which the compressor is turned off to a predetermined level, thereby enabling sufficient operation of the compressor and dehumidification.

Furthermore, when the thermostat 44 is turned off, the set temperature of the compressor control section 43 is switched to the lower limit regardless of the input signal from the input signal calculation section 47.

(Lower dotted line in FIG. 4) Furthermore, when the input signal calculation unit 47 sends out the full cooler mode signal, the control unit 53 controls the air mix door 10 to close the heater core 2, and the full heater mode signal is sent out. Air Mix Door 1
0 controls the air on the evaporator 1 side to be guided toward the core 2.

The control unit 43 controls the evaporator 1 when the temperature detected by the inside air sensor 51 and the outside air sensor 52 is higher than a predetermined value.
The contact 43 is turned on and off until the temperature drops to, for example, freezing temperature.
The off period is set to increase the operating rate of the compressor 3, and when the temperature detected by the inside air sensor 51 and the outside air sensor 52 becomes lower than a predetermined value, the compressor 3 is turned off even if the temperature of the evaporator 1 does not drop much. The operating rate of the compressor 3 is reduced by controlling the rate at which the compressor 3 is turned off.

(See Figure 4) In the above structure, when the compressor on mode switch 4'0 is off, the relay 46 is not excited, the switching contact 45 and the movable contact 45□ are in the state shown by the broken line, and the temperature sensor 49 is in the state shown by the broken line. 12. Detect the air temperature from the evaporator 1 and send its output to the input signal calculation unit 47
As a result, when the compressor 3 is turned off, the opening degree of the mix door 10 is corrected, and a step in the blowout temperature due to switching between inside and outside air is prevented.

Next, when the compressor on mode switch 40 is on and the thermostat 44 is on, the relay 46 is activated.
The compressor control section 43 operates to turn on the contact 43□, turning on the compressor 3, switching the contact 45, and causing the fixed resistor 48 to send an output to the input signal calculation section 47.

The opening degree correction fixed resistor 48 corrects the opening degree of the mix door when the compressor 3 is turned on.

The compressor control unit 43 also includes an input signal calculation unit 47.
Since signals corresponding to the inside air and outside air temperatures and signals corresponding to the surface temperature of the evaporator 1 are sent from the sensor 54, the contact 43 is controlled by these signals to control the evaporator 1.
In addition to preventing freezing of the air, the comparison level at which the contact point 43□ is turned off as the temperature of the air introduced into the evaporator 1 decreases due to a drop in the inside or outside air is increased to increase the rate at which the compressor 3 stops. , to prevent wasteful operation of the compressor 3.

When air conditioning can be sufficiently performed only by introducing outside air, the compressor on mode switch 40 is turned off and the compressor 3 is stopped.

In addition, when the outside temperature is around 0°C, such as in winter, the switch 42
operates to cut off the power circuit of relay 41 and protect the compressor.

That is, conventionally, the temperature sensor and the antifreeze sensor immediately after the evaporator are installed for control, which has the disadvantage that the opening degree of the mix door 10 changes unnecessarily, but according to this embodiment, the opening degree of the mix door 10 changes unnecessarily. When the compressor 3 is set to the on mode, a fixed resistor 35 whose resistance value remains unchanged is connected to the input signal calculation section, and when the compressor 3 is set to the off mode, a sensor that detects the air temperature from the evaporator 1 is connected. Therefore, even if the compressor 3 is stopped and outside air is introduced due to a decrease in the required cooling capacity, the opening degree of the mix door 10 is corrected in response to the difference in resistance value between the fixed resistance and the temperature sensor, and the blowout temperature is adjusted. Steps can be made smaller.

Furthermore, when the on-mode switch of the compressor 3 is turned on, the operating 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 and the cabin air. As a result, the operation of the compressor 3 can be suppressed to the necessary minimum, and power saving can be achieved.

Furthermore, when the outside air temperature is low and it is desired to drive the compressor to achieve a rapid dehumidification operation, the compressor on mode switch 40 is turned on and the thermostat 44 is turned off due to the drop in the outside air temperature.
3 is switched to the lower limit set temperature (lower dotted line in FIG. 4), and the automatic set temperature change of the compressor control unit 43 by the output signal from the input signal calculation unit 47 is canceled. The comparison level of sensor 54 can be reduced to obtain efficient dehumidification operation.

As explained above, according to the present invention, there is provided an input signal calculation unit that compares and processes a signal from the air mix door opening correction resistance unit and a signal from the outside air temperature sensor or the inside air temperature sensor, and When the temperature detected by the control unit that controls the opening degree of the air mix door based on the output from the air mix door and the temperature sensor 54 on the surface side of the evaporator falls to a predetermined comparison level, the compressor is stopped, and the outside air temperature sensor or By installing a control unit that increases the above comparison level and increases the rate at which the compressor stops as the temperature detected by the inside air temperature sensor decreases, power is saved and the dehumidification operation is effective when the outside air temperature drops. In order to do this, the comparison level of the compressor control section is switched to the lower limit by an outside air temperature detection switch, that is, a thermostat, which is activated by the outside air temperature. , a temperature sensor installed downstream of the blower that sends a signal to the input signal calculation section, and a fixed resistor that sends a signal to the input signal calculation section when the compressor is in operation mode, so that the air mix door It is possible to correct the opening degree of the air mix door without causing any fluctuation, and prevent sudden changes in the blowout temperature.

[BRIEF DESCRIPTION OF THE DRAWINGS] 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. 4 and 4 are diagrams showing the operating characteristics of the vehicle air conditioner of the present invention. 1... Evaporator, 3... Compressor, 10... Air mix door, 40...
...Compressor on mode switch, 43, 53.
...Control unit, 44...Thermostat,
45...Switching contact, 47...Input signal calculation unit, 54...Temperature sensor, 55...
・Resistance part for air mix opening correction.

Claims (1)

[Claims] 1. A cooler that cools the air from the blower, a heater that heats the air, an air mix door that adjusts the mixing ratio of cold air and warm air, a mode switch 40 that sets the compressor to on mode or off mode, and a car. Indoor temperature setting section 50
An input signal calculating section 4 that compares and calculates a signal from a mode sensor 49 located downstream of the evaporator and a signal from an inside air temperature sensor.
a first control section 53 that controls the opening degree of the air mix door based on the output from the evaporator surface side temperature sensor 5;
When the temperature detected by 4 falls to a predetermined comparison level, the compressor is stopped, and as the temperature detected by the inside air temperature sensor decreases, the outside air temperature sensor increases the comparison level and stops the compressor. In a vehicle air conditioner including a second control unit 43 that increases the ratio, an outside temperature detection switch 44 that is turned on when the outside air temperature is equal to or higher than a set temperature, a fixed resistor 48 having a predetermined resistance value, and a second control unit 43 that increases the outside air temperature. When the detection switch is on and the compressor is in on mode, the fixed resistor 4
A signal having a magnitude corresponding to the resistance value of 8 is supplied to the input signal calculation unit 47, and when in the off mode, the mode sensor 4
and a switching contact 45 for supplying a signal No. 9 to the input signal calculation section 47, and the second control section lowers the comparison level to a predetermined level when the outside temperature detection switch 44 is in conflict. A vehicle air conditioner characterized by: