JPS6233622Y2 - - Google Patents

Description

[Detailed Description of the Invention] The present invention relates to a vehicle air conditioner, and more particularly to a control device for a air conditioning unit.

Generally, in vehicle cooling systems, the refrigerant compressor is driven by the car engine, and the optimum cooling capacity is obtained at the compressor rotation speed at the normal driving speed (for example, 40 km/h). It is designed to. For this reason, when driving at high speeds, the cooling capacity becomes excessive. Conventionally, on the other hand, a part of the air cooled by the refrigerant evaporator is heated through a heater in the heating unit, and then mixed with the remaining cooling air, which is the so-called air mix method. I am trying to resolve this. However, such an air mix system has the disadvantage that a part of the engine's power is consumed to reheat the cooled air, resulting in a large energy loss.

In addition to this air mix system, in order to prevent frost from forming on the refrigerant evaporator, an electromagnetic clutch is turned on that detects the temperature of the cold air blowing out of the refrigerant evaporator and engages and disconnects power transmission between the engine and the compressor. The compressor is also driven and stopped by turning it off. The temperature of this electromagnetic clutch-off is set to the limit temperature at which frost will form on the refrigerant evaporator, and when the cooling capacity is excessive during high-speed driving, the temperature at the outlet side of the refrigerant evaporator will drop quickly, so the maximum cooling capacity will be achieved. The disadvantage is that the compressor is frequently driven and stopped under the condition that the compressor is running, which places a large shock and load on the drive system and causes discomfort to the driver.

In view of the above-mentioned drawbacks, the present invention provides a control device for a vehicle air conditioner that can suppress the cooling capacity by reducing the compression capacity of the compressor when the cooling capacity becomes excessive due to high-speed driving, etc. This is what we are trying to provide.

Another object of the present invention is to provide a control device that can reduce the shock and load on the drive system due to driving and stopping of the refrigerant compressor.

In the present invention, the above-mentioned air mix damper closes to reduce the amount of cold air passing through the heater when a large cooling capacity is required, and opens to increase the amount of cold air passing through the heater when it is not required. Focusing on the fact that there is a proportional relationship between the required cooling capacity and the opening of the air mix damper, the actual required cooling capacity is calculated from the opening of the air mix damper, and the compressor's compression is adjusted accordingly. It is characterized by being able to change its abilities.

Embodiments of the present invention will be described below with reference to the drawings.

FIG. 1 is a schematic diagram of a vehicle air conditioner using the air mix method.

When used as a cooling device, the inside air inlet 11
The air sucked in by the blower 12 from the refrigerant evaporator 1
The air mix damper 14 adjusts the mixing ratio of the air that has passed through the heater 21 and been reheated and the cold air that has bypassed the heater 21, and the air is cooled and dehumidified by passing through the air outlet 15. By blowing air from the inside of the car, the temperature inside the car is maintained at a comfortable temperature. 2
2 is an outside air inlet, 16, 17, 23, and 24 are switching dampers, and 25 and 26 are air outlets. The opening degree of the air mix damper 14 is adjusted manually, and the opening degree is adjusted by a damper opening adjustment mechanism based on factors such as the temperature inside the vehicle, the temperature outside the vehicle, and the temperature on the outlet side of the refrigerant evaporator 13. There is something.

Figure 2 shows an example of the cooling capacity characteristics of the variable compression volume refrigerant compressor used in the present invention with respect to the rotational speed, and shows the compression volume of two large volume CC ₁ and small volume CC ₂ .
The characteristics of a compressor that is variable in stages are shown by curves C ₁ and C ₂ . Curve C shows the characteristics of a constant volume compressor.

As this type of compressor, a scroll type compressor proposed by the present applicant (Japanese Unexamined Patent Publication No. 148089/1989) is used. To put it simply, this compressor consists of a pair of spiral bodies that are engaged with each other at different angles, and one spiral body is given a relative rotational motion, so that the airtight space formed between the two spiral bodies is centered. The compressed fluid is discharged from the center by moving the compressed fluid in the same direction as the volume decreases. Then, by configuring the first suction fluid in the sealed space formed between the two spiral bodies to escape from the middle to the suction side using a solenoid valve to reduce the actual suction volume, the compression volume can be adjusted in two stages. It is possible to switch to .

Q is the cooling capacity (for example, 2300 Kcal/h) required to maintain the interior temperature of a normal passenger car at a comfortable temperature (23 to 25 degrees Celsius) in the summer, and the value varies depending on outside air conditions, set temperature, etc. different.

A case will be described in which such switching of the volume of the refrigerant compressor is performed using a micro switch attached to an air mix damper.

Figure 3 shows the circuit that controls driving and stopping of the refrigerant compressor to prevent frost formation on the refrigerant evaporator mentioned above.
An embodiment is shown in which an opening/closing circuit of a solenoid valve for switching the volume of a refrigerant compressor is combined.

31 is a battery power supply, 32 is a main switch,
Th is a thermistor that detects the temperature of the air discharged from the refrigerant evaporator, 37 is an electromagnetic clutch excitation winding, 38 is a solenoid for opening and closing the electromagnetic valve, and S is a microcontroller connected to the air mix damper and turned on at a predetermined opening angle. It's a switch. Reference numeral 36 is a comparison amplifier, which calculates the reference voltage V ₀ at point b and the resistance value of the thermistor Th, that is,
The voltage at point a determined by the temperature of the blown air is compared with the voltage _V1 at point a, and the transistor is
The electromagnetic clutch 37 is controlled by turning on and off the Tr.

To briefly explain the operation, the main switch 32
If the temperature of the blowing air is higher than the set value when the ignition is turned on, V ₁ > V ₀ and the output of the amplifier 36 becomes a high level, the transistor Tr is turned on and the electromagnetic clutch 37 is energized, thereby compressing the refrigerant. The machine is driven. When the temperature of the blown air becomes lower than the set value, the transistor Tr is turned off because V ₁ <V ₀ , the electromagnetic clutch 37 is de-energized, and the refrigerant compressor is stopped.

In addition to driving and stopping the refrigerant compressor, the temperature inside the vehicle is controlled by adjusting the opening angle of the air mix damper. When the opening angle of the air mix damper reaches a predetermined value, the micro switch S is turned on. The electromagnetic valve opening/closing solenoid 38 is then energized, and the refrigerant compressor explained in FIG. 1 is driven with a small volume _CC2 . In other words, when the air mix damper starts to open, it means that the cooling capacity of the refrigerant compressor that is being driven at a certain rotation speed exceeds the actually required cooling capacity, and this excess is used as the air mix damper. It is almost proportional to the opening angle of the damper. Therefore, the opening angle of the air mix damper at which the micro switch S is turned on is determined by the excess cooling capacity at that time and the cooling capacity reduced by switching the volume of the refrigerant compressor from the large volume CC ₁ to the small volume CC ₂ . are set to be almost the same.

In this way, when the cooling capacity becomes excessive due to high-speed driving, etc., this is immediately detected and the refrigerant compressor is switched to the small-volume _CC2 , reducing the load on the engine and contributing to energy savings. By switching to CC ₂ , the cooling capacity is reduced and the drop in air temperature on the outlet side of the refrigerant evaporator is also slowed down, so the refrigerant compressor does not start and stop frequently, reducing shock to the engine. can.

Note that when the air mix damper is closed, the micro switch S is also turned off, the solenoid valve is also closed, and the refrigerant compressor is switched to large capacity CC ₁ and driven.

Note that refrigerant compressors with variable compression capacity in stages are not limited to those with variable compression volume; for example, by providing a bypass path between the inlet and outlet of the compressor, the amount of refrigerant bypass can be adjusted in stages. Alternatively, a throttle valve may be provided on the inlet side of the compressor so that the amount of refrigerant supplied can be adjusted in stages, or a compressor with variable clearance volume may be used to vary the compression capacity. Further, in such a method, the compression capacity can be made continuously variable.

Further, the micro switch for detecting the opening degree of the air mix damper may be attached directly to the air mix damper, or may be attached to a temperature control lever or link that drives the air mix damper.

As explained above, this invention uses a refrigerant compressor with variable compression capacity, and when there is excess cooling capacity, the compression capacity is reduced by the amount of excess cooling capacity, thereby reducing the engine load, thereby contributing to energy savings. . In addition, since the compression capacity is variable and cooling capacity close to the required cooling capacity can be obtained, the number of times the compressor is driven and stopped during cooling operation is much smaller than before, contributing to reducing the shock and load on the drive system. The effect is great.

[Brief explanation of drawings]

Figure 1 is a schematic configuration diagram of a vehicle air conditioner using the air mix method, Figure 2 is a cooling capacity characteristic diagram of the variable compression capacity refrigerant compressor used in the present invention versus rotational speed, and Figure 3 is a diagram of the cooling capacity characteristic of the variable compression capacity refrigerant compressor used in the present invention. FIG. 3 is a circuit diagram of an embodiment of the invention. In the figure, 11 is the inside air inlet, 12 is the blower, and 13
14 is a refrigerant evaporator, 14 is an air mix damper, and 15 is a refrigerant evaporator.
21 is a heater, 36 is a comparison amplifier, 3
7 is an electromagnetic clutch excitation winding, 38 is a solenoid for opening and closing the electromagnetic valve, and S is a micro switch.

Claims (1)

[Scope of utility model registration request] a refrigerant compressor with variable compression capacity that receives part of the power of a vehicle engine via an electromagnetic clutch; a refrigerant evaporator that is supplied with refrigerant from the refrigerant compressor;
By detecting the temperature of the air blown from the refrigerant evaporator and controlling the three-terminal active element on and off in accordance with the detection signal, the excitation coil of the electromagnetic clutch connected in series with the three-terminal active element is connected to the power source. In a vehicle air conditioner equipped with a circuit for controlling energization on and off, the opening degree of an air mix damper disposed on the windward side of a heater disposed on the leeward side of the refrigerant evaporator is detected. A vehicle characterized in that a series circuit of a micro switch and a solenoid for opening and closing a solenoid valve for switching the compression capacity of the refrigerant compressor is connected in parallel to a series circuit of the three-terminal active element and the excitation coil. Air conditioner control device.