JPS6343128Y2 - - Google Patents

Description

[Detailed Description of the Invention] (Industrial Application Field) This invention relates to a device for controlling a compressor and an air mix door in an air conditioner used in an automobile.

(Prior Art) In general, an air conditioner for an automobile has a compressor in its cooling cycle that is driven by a driving engine, dehumidifies and cools air through an evaporator in this cooling cycle, and the dehumidified and cooled air passes through an air mixture door. It is divided into those that pass through the heater core and those that bypass it, and are then mixed and blown into the passenger compartment. Therefore, the evaporator has a temperature control function that works together with the heater core and the air mix door to adjust the amount of heat exchange of the air and adjusts the temperature of the blown air, and also has a dehumidification function that dehumidifies the air passing through. This function is adjusted by turning the compressor on and off.

However, conventionally, as a method that emphasizes the adjustment of the temperature control function of the evaporator, for example,
As shown in Publication No. 58-39083, air cooled by an evaporator is used to control the heater core as well as the opening degree of the air mix door and the on/off temperature of the compressor according to the heat load in the vehicle interior. It is known to reduce the rate at which air passes through and is reheated, lowering the operating rate of the compressor and saving power.

In addition, as an example of placing emphasis on the dehumidifying function of the evaporator, for example, as shown in Japanese Patent Application Laid-open No. 174017/1982, when the wiper switch is turned on, the compressor is turned on and the dehumidified air is sent to the window glass. Furthermore, in Japanese Patent Application Laid-Open No. 59-14564, when the wiper switch is turned on, the operating air temperature of the compressor is set to a low temperature, and when it rains in the spring and autumn, the compressor is turned on. It has also been shown that driving can also be used to prevent fogging of window glass.

(Problem to be solved by the invention) However, in the past, it has been almost impossible to find anything that controls both of the above functions at the same time. This is to switch the compressor on/off temperature to the lower limit when the outside air temperature is below a predetermined value. There was a problem that proper control was not possible because there was only a weak correlation with the fogging of the glass.

Therefore, the object of this invention is to provide a control device for an air conditioner for an automobile that can more appropriately prevent fogging of window glass while performing power-saving control using a variable thermostat.

(Means for solving the problem) The gist of this invention is to provide a heat load detection means for detecting the amount of heat load in the vehicle interior, and to open the air mix door according to the output of the heat load detection means. air mix door control means for controlling the degree of cooling of the evaporator; first control signal generation means for generating a signal for controlling the on/off temperature of the compressor according to the output of the heat load detection means; and an evaporator sensor for detecting the degree of cooling of the evaporator. a second control signal generating means that compares the output of the evaporator sensor with a predetermined value and generates a signal for setting the on/off temperature of the compressor to a lower limit; and generating the first control signal according to the operating state of the wiper. The present invention includes a control signal selection means for selecting the output of the compressor and the second control signal generation means, and a drive control means for turning on and off the compressor in accordance with the control signal selected by the control signal selection means. The control signal selection means may select the output of the second control signal generation means over the output of the first control signal generation means when the wiper switch is turned on.

(Function) Therefore, in the operating state of the wiper, for example, when the wiper switch is turned off and the wiper is stopped, the output of the first control signal generation means is selected by the control signal selection means, and the on/off temperature of the compressor and the output of the first control signal generation means are selected. While the opening degree of the air mix door is controlled according to the heat load in the vehicle interior to achieve power saving control, for example, when the wiper switch is turned on and the wipers are operated, the second control is performed by the control signal selection means. Since the output of the signal generating means is selected and the on/off temperature of the compressor is set to the lower limit, fogging of the window glass can be appropriately prevented, and therefore the above object can be achieved.

(Example) Hereinafter, an example of this invention will be described with reference to the drawings.

In Fig. 1, one embodiment of this invention is shown, in which an inside air inlet 2 and an outside air inlet 3 are formed in the form of two branches on the most upstream side of an air conditioning duct 1, and the inside and outside air switching is done at the divided part. A door 4 is provided, and the air to be introduced is selected between inside air and outside air through the inside/outside air switching door 4.

The blower 5 is for sucking air into the air conditioning duct 1 and sending it to the downstream side, and an evaporator 6 and a heater core 7 are arranged on the downstream side of the blower 5.

The evaporator 6 constitutes a cooling cycle together with a compressor 8, a condenser 9, a liquid tank 10, and an expansion valve 11.
The heater core 7 is inserted into a hot water cycle in which engine cooling water circulates. The compressor 8
is connected to the engine via an electromagnetic clutch 12, and is turned on and off by connecting and connecting this electromagnetic clutch 12.

In front of the heater core 7, there is an air mix door 1.
3 is provided, and this air mix door 13
is the air passing through the heater core 7 and the heater core 7
The ratio of bypassing air to air is determined by its opening degree, and is operated by an actuator 14 connected via a link mechanism.

Furthermore, the downstream side of the air conditioning duct 1 is divided into an upper outlet 15, a lower outlet 16, and a defrost outlet 17, which open into the vehicle interior, and mode doors 18, 19 are provided in the separated parts, door 1
By operating 8 and 19, a desired blowing mode can be obtained.

Further, an interior temperature sensor 20 that detects the temperature inside the vehicle, an outside temperature sensor 21 that detects the outside temperature,
A solar radiation sensor 22 that detects the amount of solar radiation entering the vehicle interior
and a temperature setting device 23 for setting the temperature in the vehicle interior, these detection signals are input to a signal calculation circuit 24, and the heat load in the vehicle interior is comprehensively calculated in this signal calculation circuit 24.
22, a temperature setting device 23 and a signal calculation circuit 24 constitute a thermal load detection means 25.

The signal from the signal calculation circuit 24 is input to the air mix door control circuit 27 together with the output of the potentiometer 26 that detects the opening degree of the air mix door 13, and the control signal from the air mix door control circuit 27 is transmitted via the drive circuit 28. is output to the actuator 14, and the opening degree of the air mix door 13 is controlled according to the heat load while being fed back with the output from the potentiometer 26, and the potentiometer 26, the air mix door control circuit 27, and the drive The circuit 28 and the actuator 14 constitute an air mix door control means 29.

In this embodiment, the evaporator sensor 30 is composed of a temperature sensing element such as a thermistor provided near the outlet side of the evaporator 6, and is adapted to detect the degree of cooling of the evaporator 6 as the temperature of the outlet air. As another embodiment, the refrigerant may be inserted directly into the evaporator 6 to detect its evaporation temperature, or the temperature or pressure of the refrigerant entering the evaporator 6 may be detected. The detection signal from this evaporator sensor 30 is transmitted to a variable thermo circuit 31 constituting a first control signal generating means and a comparison circuit 32 constituting a second control signal generating means described below.
is output to.

The variable thermo circuit 31 receives the detection signal from the evaporator sensor 30 as well as the signal from the heat load detection means 25, and generates a signal for controlling the compressor 8 according to the heat load, as shown in FIG. As shown by the solid line, when the heat load T is small, the compressor on/off temperature t is set high, and as the heat load increases, it gradually decreases until it reaches the lower limit (slightly higher than the evaporator freezing temperature _t0 ). The temperature is set at, for example, 2 to 4°C. On the other hand, the comparison circuit 32 compares the input signal from the evaporator sensor 30 with a predetermined value from the fixed resistor 33, and as shown by the dotted line in FIG.
The compressor on/off temperature t is set to the lower limit.

The selection circuit 34 constituting the control signal selection means is
The outputs from the variable thermo circuit 31 and the comparator circuit 32 are selected depending on the operating state of the wiper, and in this embodiment, the output is controlled by an on/off signal from the wiper switch 36 inputted via a buffer 35. , wiper switch 36
When the wiper switch 36 is off, the output of the variable thermo circuit 31 is selected, and when the wiper switch 36 is on, the output of the comparison circuit 32 is selected. Further, when the wiper switch 36 is turned on, power is supplied to the wiper motor 37 via the wiper control circuit 38 to drive a wiper (not shown) at a predetermined rotation speed. Note that instead of directly controlling the selection circuit 34 with the output of the wiper switch 36 as in this embodiment, as another embodiment, a determination circuit 39 inputting a signal from the wiper control circuit 38 is provided to operate the wiper. The output from the comparator circuit 32 may be selected by counting the frequency of rotation and when the frequency is high, or by detecting the number of rotations of a continuous intermittent wiper and detecting the number of rotations.

The control signal selected by this selection circuit 34 is applied to the air conditioner relay 40 constituting the drive control means.
When the air conditioner switch 41 is on and the air conditioner relay 40 is on, the electromagnetic clutch 12 is energized and the compressor 8 is driven.

In the above configuration, when the main switch (not shown) is turned on, the signal calculation circuit 24 starts calculation, the heat load detection means 25 outputs a signal corresponding to the heat load in the vehicle interior, and the air mix door control means 29 controls the air mix door 13. The opening degree is controlled. That is, when the heat load in the vehicle interior is large, the air mix door 13 is moved to the cool side where the proportion of air passing through the heater core 7 is small, and as the heat load gradually decreases, the proportion of air passing through the heater core 7 is reduced. Moved to the increasing heat side.

Here, when the air conditioner switch 41 is turned on and the wiper switch 36 is kept off, the output of the variable thermo circuit 31 is selected in the selection circuit 34, so the output from the variable thermo circuit 31 is applied to the air conditioner relay 40. As a result, the on/off temperature of the compressor 8 is controlled according to the heat load, as shown by the solid line in FIG. That is, as the heat load decreases, the on/off temperature of the compressor 8 increases, and the operating rate of the compressor 8 decreases, resulting in power savings.

For this reason, the on/off temperature of the compressor 8 is set high even when the heat load is small, such as in spring and autumn, but when it rains, the wiper switch 36 is turned on and the wiper is driven, so the selection circuit 34
In this case, the output of the comparison circuit 32 is selected, and the compressor 8 is turned on and off near the freezing temperature of the evaporator 6. Therefore, the operating rate of the compressor 8 increases to the maximum level, so that the air that has passed through the evaporator 6 is efficiently dehumidified and the window glass is prevented from fogging up.

(Effects of the invention) As described above, according to this invention, the opening degree of the air mix door is controlled according to the heat load inside the vehicle interior, and the on/off temperature of the compressor is controlled according to the heat load inside the vehicle interior. A first control signal generating means for controlling the compressor and a second control signal generating means for setting the on/off temperature of the compressor to a lower limit are provided,
Since the control signal selection means for selecting these control signals depending on the operating state of the wiper is provided, control for power saving and control for dehumidification can be performed simultaneously depending on the operating state of the wiper. Moreover, since there is a high possibility that the window glass will fog up when the wiper is operated in the compressor on mode, it is possible to save power and appropriately prevent the window glass from fogging up. Furthermore, compared to a system in which a new switch is added for dehumidification, this invention can also be used as a wiper switch, etc., so it has fewer parts and is less cumbersome to operate.

[Brief explanation of the drawing]

FIG. 1 is a block diagram showing an embodiment of this invention, and FIG. 2 is a characteristic diagram showing the control characteristics of the on/off temperature of the compressor. 6... Evaporator, 8... Compressor, 1
3... Air mix door, 25... Heat load detection means, 29... Air mix door control means, 31...
...Variable thermo circuit constituting the first control signal generation means, 32...Comparison circuit constituting the second control signal generation means, 34...Selection circuit constituting the control signal selection means, 36...Wiper switch, 40...
...An air conditioner relay that constitutes the drive control means.

Claims (1)

[Scope of Claim for Utility Model Registration] 1. A heat load detection means for detecting the amount of heat load in the vehicle interior, an air mix door control means for controlling the opening degree of the air mix door according to the output of the heat load detection means, and the above heat load detection means. first control signal generating means for generating a signal for controlling the on/off temperature of the compressor according to the output of the means;
an evaporator sensor that detects the degree of cooling of the evaporator; a second control signal generating means that compares the output of the evaporator sensor with a predetermined value and generates a signal that sets the compressor on/off temperature to a lower limit; control signal selection means for selecting the outputs of the first control signal generation means and the second control signal generation means in accordance with the control signal selection means; and drive control for turning on and off the compressor in accordance with the control signal selected by the control signal selection means. 1. A control device for an air conditioner for an automobile, comprising: means. 2. A utility model registration request characterized in that the control signal selection means selects the output of the second control signal generation means with priority over the output of the first control signal generation means when the wiper switch is turned on. A control device for an air conditioner for an automobile according to scope 1.