JPS591957A - Air conditioner for car - Google Patents

Abstract

(57) [Summary] This bulletin contains application data before electronic filing, so abstract data is not recorded.

Description

[Detailed description of the invention] The present invention relates to a vehicle air conditioner.

In a conventional automobile air conditioner, as shown in the system diagram in Figure 1, an engine l drives a refrigerant compressor (hereinafter referred to as a compressor) 2 through a magnetic latch, and the high temperature discharged from the compressor 2 is The high-pressure refrigerant is cooled and liquefied in the condenser 4 by air blown by an engine-driven fan 8, and is temporarily stored in the receiver 5. It is expanded by the expansion valve 6 where the amount is determined, is evaporated in the evaporator 7, and is sucked into the compressor 2.

Here, 9', 9, 10, 11.12 are the pipes that connect these devices.

The operation control of such a refrigerant circuit is carried out by turning on and turning on the electromagnetic clutch 3 to stop driving the compressor 2 so that the temperature of the evaporator or the evaporator outlet temperature remains constant using a thermostat 14 that turns on and off at a predetermined temperature. The air introduced by the blower 13 is cooled by the evaporator 7, and is introduced into the heater 16 as cold air. 18yo υ
Hot water is introduced into the heater 16, and the cold air blown from the eno (bore tuff) passes through the heater 16 according to the opening degree of the air mix damper 19 and is mixed with the heated warm air and the heater 16.
)(inno(su)), and then the heater 16
The cold air and the warm air are mixed downstream and are blown into the vehicle interior 20 at an appropriate temperature.

At this time, the opening degree of the air mix damper 19 is operated by the passenger, but recently there are some models that automatically control the opening degree of the air mix damper 19 so that the temperature inside the vehicle is at the set value. 15 is a heat sensitive part of the thermostat 14.

However, in such an air conditioning system, the cold air cooled by the evaporator 7 is reheated by a heater and blown into the car so that the temperature inside the car becomes an appropriate temperature, and the reheated air by the heater is not cooled by the evaporator. The compressor is frequently turned on and off in order to keep the evaporator temperature or the temperature of the air blown from the evaporator constant, which is contrary to energy saving and wasteful operation, which deteriorates the durability of the electromagnetic clutch and the drivability due to the turning on and off of the compressor.

The present invention was proposed in view of the above circumstances, and aims to provide a vehicle air conditioner that not only saves energy but also increases the durability of the electromagnetic clutch and avoids deterioration of drivability. , refrigerant compressor, condenser, expansion valve.

In a vehicle air conditioner equipped with a refrigerant circuit such as an evaporator, a refrigerant flow control valve is inserted into the refrigerant circuit between the evaporator and the refrigerant compressor to control the refrigerant flow rate. The valve is characterized in that the amount is controlled according to the air conditioning load.

An embodiment of the present invention will be explained with reference to the drawings. Fig. 2 is a system diagram thereof, Fig. 3 is an enlarged cross-sectional view showing the refrigerant control valve shown in Fig. 2, and Fig. 4 is a circuit diagram showing the controller shown in Fig. 2. , FIG. 5 is a diagram showing the relationship between the refrigerant control valve opening degree and electrical resistance of the upstream sensor and potentiometer 29 in FIG. 2.

In the above figure, the same symbols as in Fig. 1 indicate the same members as in the same figure, and first, in Figs.
The high-pressure liquefied refrigerant flowing from the refrigerant is rapidly expanded by the expansion valve 6, vaporized by the evaporator 7, and sucked into the compressor 2 via the refrigerant control valve 21.

Here, the refrigerant control valve 21 is controlled by a controller 24, which will be described later, in response to a signal from an upstream sensor 23 that detects the air temperature on the upstream side of the evaporator (which may be provided in the air inside the car or outside the car). When the temperature of the upstream sensor 23 is high, the opening degree becomes small, and when the temperature of the upstream sensor 23 is low, the opening degree becomes small. 22 is a sensor that detects the temperature of the evaporator tough or a temperature near it (the temperature of the blown air may also be used);
When the evaporator temperature or the temperature near it reaches a predetermined temperature (in this case, a temperature of about 0°C to prevent frosting), a thermo circuit is configured that turns off the electromagnetic clutch 3 by the controller 24, thereby turning off the converter 2. . 25
2 is an air conditioner switch that operates the cooler, 26 is a butterfly valve that controls the flow rate by changing the opening degree, and its shaft 26' is a mechanical seal 2 that prevents refrigerant leakage.
7 is directly connected to the electric motor 28, it is also connected to a potentiometer (rotary type variable resistor) 29 that detects the valve opening, and the rotation of the electric motor 28 by the controller 24 changes the pulp opening. By controlling the refrigerant flow rate by changing the refrigerant flow rate and configuring the valve body of the refrigerant control valve 21 as a butterfly valve, it is advantageous to reduce the operating force. The upstream sensor 23 and the potentiometer 29 have characteristics as shown in FIG. 5, and the opening degree of the refrigerant control valve 21 is controlled via the controller 24 and the electric motor 28 so that the sum of their respective resistance values is always a constant value. Control.

That is, in FIG. 4, the branch voltage VA at the branch point A due to the combined resistance of the upstream sensor 23 and potentiometer 29 and the fixed resistor R1 of the controller 24 is input to the comparators OPI and OF2, and the branch voltage VA is input to the comparators OPI and OF2,
, R4, for example, if the branch voltage VA is high (cooling negative is turned on, Tr3
is turned off and +12V is applied to the electric motor 28.

At this time, comparator OP2 is off and transistors Tr4.
Tr5 is turned off, and Tr6 is turned on and becomes the ground side of the shimmo motor 28, so that the shimmo motor 28 operates in the direction of closing the refrigerant control valve opening, and therefore the potentiometer 29 interlocked with this When the resistance value of is small, the branch voltage VA decreases, the comparator OPl is turned off, and the electric motor is turned off.

Second, when the cooling load increases and the temperature of the upstream sensor 23 rises, its resistance decreases.

Branch voltage VA decreases, comparator OP2 turns on, and transistor T r 4. Tr 5 turns on and Tr
6 is off, +12V is applied to the electric motor 28, and at this time, the transistor Tr3 at the other end is on and connected to the ground side, so the electric motor 28 operates to open the refrigerant control valve 21, and therefore the potentiometer 29 increases, the branch voltage VA rises, the operation of the comparator OP2 is turned off, and the shimming motor 28 stops.

On the other hand, when the valve opening degree of the refrigerant control valve 21 increases and the refrigerant flow rate increases, the cooling capacity increases and the evaporator temperature decreases.When the temperature drops to around 70 strokes, the resistance value of the evaporator sensor 22 increases. 1, the branch voltage VB of the branch point B rises, the comparator OP3 turns off, and the transistor T r7. The Tr8 is turned off, the electromagnetic clutch 3 is turned off, the compressor 2 is stopped, and frosting of the vaporizer is prevented.

The heat sensitive part 6' of the expansion valve 6 detects the pipe temperature close to the refrigerant temperature between the evaporator outlet and the refrigerant control valve 21, and controls the opening degree of the expansion valve 6 so that the degree of superheating of the refrigerant at the evaporator outlet is optimized. By doing this, the amount of refrigerant inflow is controlled. One! When the opening degree of the refrigerant flow control valve 21 becomes smaller, the evaporation pressure inside the evaporator increases, and if the expansion valve opening degree remains unchanged from the previous state, a liquid back-up state occurs, so the temperature of the expansion valve heat-sensitive part 6' increases. decreases, its internal pressure decreases, and the expansion valve operates to close the valve opening.In the opposite case, it operates to open the valve opening, and the refrigerant flow rate is also controlled by this.

According to such a device, when the cooling load is large according to the upstream sensor 23 and when the temperature of the upstream sensor 1 is high, the valve opening of the refrigerant control valve 21 increases, increasing the refrigerant flow rate and increasing the cooling capacity. However, when the cooling load decreases, that is, when the temperature of the upstream sensor decreases, the degree of opening of the refrigerant control valve 21 is reduced, the refrigerant flow rate is reduced, and the cooling capacity is reduced.

At that time, the driving power of the compressor is determined by the amount of work and the flow rate of the refrigerant.

By controlling the refrigerant flow rate to the optimum state according to the cooling load, it is possible to maintain the compressor power in the optimum state and eliminate unnecessary power that is used in conventional systems. Second, in the refrigerant flow rate control range, the evaporator temperature rises and does not reach the frost temperature, allowing continuous operation of the compressor, which eliminates problems caused by frequent turning on and off of the compressor as in conventional systems. In addition, when the refrigerant control valve 21 is fully open, the compressor is automatically turned off when the evaporator temperature reaches the frost point, and all these controls are performed automatically.
By controlling the cooling capacity appropriately to maintain a comfortable temperature inside the vehicle, the operation by the occupants is omitted, contributing to safe driving.

In addition, in the above embodiment, when the cooling load is small and the refrigerant control valve opening is small, the suction pressure to the compressor decreases too much and there is a tendency to operate in a vacuum, so in order to prevent this, the compressor suction pressure It is practical to provide a protection device that turns on below a predetermined pressure.

In short, according to the present invention, in a vehicle air conditioner equipped with a refrigerant circuit including a refrigerant compressor, a condenser, an expansion valve, and an evaporator, a refrigerant flow rate is provided in the refrigerant circuit between the evaporator and the refrigerant compressor. By inserting a control valve and controlling the refrigerant flow rate control valve according to the air conditioning load, energy savings can be achieved.
The present invention is extremely useful industrially because it provides a vehicle air conditioner with good durability and drivability.

[Brief explanation of drawings]

Fig. 1 is a system diagram of a known automobile air conditioner, Fig. 2 is a system diagram showing an embodiment of the present invention, Fig. 3 is an enlarged sectional view showing the refrigerant control valve of Fig. 2, and Fig. 4 is a system diagram showing an embodiment of the present invention. 10 is a circuit diagram showing the controller of FIG. 9. FIG. FIG. 5 is a diagram showing the relationship between the refrigerant control valve opening degree and electrical resistance of the upstream sensor and potentiometer 29 in FIG. 2. l...Engine, 2...Compressor, 3...Electromagnetic clutch, 4...Condenser, 5...Receiver, 6...Expansion valve, 6'...Heat sensitive part, 7...Evaporator, 8-71:
/, 9. 9', 10゜11.12...Piping, 16
...Heater, 17..Water pipe% 18..Exit vibe, 19..Air mix damper, 20..Inside the car, 2
1...Refrigerant control valve, 22...Sensor, 23...Upstream sensor% 24...Controller, 25...-Air conditioner switch, 26...Butterfly valve, 26'...Shaft, 27...Mechanical seal, 28... electric motor, 2
9...Potentiometer, OPI, OF2...Comparator, Trl, Tr2. Tr3. 'rr51 Tr6゜Tr
7. Tr8...transistor, sub-agent patent attorney Masafumi Tsukamoto

Claims (1)

[Claims] In a vehicle air conditioner equipped with a refrigerant circuit including a refrigerant compressor, a condenser, an expansion valve, and an evaporator, a refrigerant flow control valve is inserted into the refrigerant circuit between the evaporator and the refrigerant compressor,
An air conditioner for a vehicle, characterized in that the refrigerant flow rate control valve is configured to control the amount according to the air conditioning load.