JP3474972B2 - Automotive air conditioners - Google Patents

Description

Description: BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to an air conditioner for a motor vehicle, and more particularly, to independently controlling the flow of refrigerant to a front seat evaporator and a rear seat evaporator. The present invention relates to an air conditioner for a vehicle using a motor-operated valve. 2. Description of the Related Art A conventional refrigeration cycle for a car air conditioner in which the inside of a car is divided into a plurality of areas and air-conditioning is carried out or a car-mounted refrigerator is provided, as shown in FIG. 2, a liquid receiver 3, an electromagnetic valve 41, an expansion valve 42, a refrigerant evaporator 5, and a receiver tank 6. Each device is connected by a pipe 9 to form a refrigerant circulation path. are doing.
The expansion valve 42 is provided with a sensor 8 provided on the outlet side of the refrigerant evaporator 5.
The degree of opening is controlled by the outlet temperature detected by 1,
The flow rate of the refrigerant flowing into the refrigerant evaporator 5 is controlled. The refrigerant evaporator 5 includes a front-seat refrigerant evaporator 5a that forms a front-seat system, and a rear-seat refrigerant evaporator 5b that forms a rear-seat system.
And a refrigerant evaporator 5c for a refrigerator constituting a system for a refrigerator
Are arranged. On the refrigerant inlet side of each refrigerant evaporator 5,
Solenoid valves 41a, 41b, 41c and expansion valves 42a, 42
b and 42c are inserted in series as shown to constitute each system. In such a refrigeration cycle for a car air conditioner, for example, when there is no occupant in the rear seat, a solenoid valve 41b disposed on the refrigerant inlet side of the rear-seat refrigerant evaporator 5b is closed to waste cooling output. To improve cooling output efficiency. [0004] In such a refrigeration cycle for a car air conditioner, when cooling is started by opening the inlet side electromagnetic valve 41 of the refrigerant evaporator 5 of another system during cooling operation using one of the systems. When the solenoid valve 41 is suddenly opened, the high-pressure liquid refrigerant at the inlet side of the solenoid valve passes through the expansion valve 42 and passes through the refrigerant evaporator 5.
Is rapidly released into the low-pressure gas refrigerant, causing vibration noise (noise like shooting an empty cannon) due to pulsation of the fluid (refrigerant) and abnormal pressure change, and impairing the quietness of the cabin. was there. Further, when the cooling operation of any of the systems is stopped during the cooling operation using a plurality of systems, if the solenoid valve 41 of the system is closed suddenly, the liquid from the condenser 2 to the liquid receiver 3 and the expansion valve are expanded. Since the flow of the refrigerant toward the refrigerant evaporator 5 via the valve 42 is suddenly blocked, vibration noise due to the pulsation of the refrigerant (water hammer effect: water hammer phenomenon) is generated in the piping, and the quietness of the vehicle compartment is impaired. There was a problem. [0006] This generation of noise is a very unpleasant factor in a closed narrow space such as a car,
It is necessary to reduce as much as possible. At this time,
In an air conditioner for an automobile, it is particularly necessary to suppress the generation of noise in the piping since the piping for the refrigerant must be provided near the vehicle interior. In order to cope with this, it is conceivable to perform a soundproofing treatment on the piping, but there is a problem from the viewpoint of cost and increase in weight. [0007] These problems of noise generation occur depending on the operating characteristics of a solenoid valve used as an on-off valve in a conventional car air conditioner refrigeration cycle. That is, this solenoid valve has a structure in which, when power is supplied to the electromagnetic coil, the plunger instantaneously moves in the valve opening direction and opens, and when the power is turned off, the plunger instantaneously moves in the valve closing direction and closes. For this reason, it has been caused by a sudden inflow or interruption of the refrigerant due to the opening and closing of the solenoid valve. Further, the solenoid valve needs to always apply a voltage during its operation, and always consumes energy in the operating state. Therefore, there is a problem in using an electromagnetic valve when it is necessary to minimize energy consumption as in an air conditioner for an automobile. Further, when an electromagnetic valve is used, it is necessary to use an expansion valve for controlling the flow rate of the refrigerant in combination, so that the number of parts and the weight become heavy, and there is a problem in adopting it for an automotive air conditioner. The present invention has been made in order to solve the above-mentioned conventional problems in a refrigeration cycle for a car air conditioner, and has an opening / closing valve 41 provided on a refrigerant inlet side of a refrigerant evaporator 5. With a structure that opens and closes slowly, the change in the flow rate of refrigerant during opening and closing of the on-off valve is gradual, generating vibration noise due to pulsation of fluid when the valve is opened and water when closing the valve. It is an object of the present invention to provide an automotive air conditioner that prevents the generation of vibration noise due to the hammer phenomenon. Further, the present invention reduces the energy consumption of the on-off valve, makes the on-off valve small and lightweight, reduces the size and weight of the entire device, and contributes to the improvement of the power performance and fuel efficiency of the automobile. Aim. In order to solve the above problems, the present invention provides a refrigeration cycle having a plurality of refrigerant evaporators and supplying a refrigerant compressed by a compressor to each of the refrigerant evaporators. provided in an automotive air conditioner, an opening and closing valve for controlling the flow rate of refrigerant the provided coolant conduit to the refrigerant evaporator, and control means for controlling the opening and closing speed of the opening and closing valve having a
Then, the on-off valve was an incompletely closed electric valve. The opening and closing operation of the motor-operated valve can be gently controlled by a pulse signal based on the temperature of the refrigerant evaporator of the refrigeration cycle of an air conditioner for an automobile. The flow of the refrigerant into or out of the heat exchanger is slowly increased or decreased, and the flow rate of the refrigerant to the refrigerant evaporator can be accurately and slowly controlled. It is possible to prevent the occurrence of abnormal noise due to the water hammer phenomenon. Embodiments of the present invention will be described below with reference to the drawings. FIG. 1 is a conceptual diagram of a refrigeration cycle of an automotive air conditioner according to the present invention. In the figure, the same reference numerals as those in FIG. 6 indicate the same or equivalent parts. The refrigeration cycle of the automotive air conditioner of the present invention will be described using an example having two evaporator systems, an evaporator system for a front seat and an evaporator system for a rear seat. The refrigeration cycle of the automotive air conditioner includes a compressor 1, a condenser 2, a liquid receiver 3, an electric valve 4, a refrigerant evaporator 5, a receiver tank 6, and an inlet of the evaporator 5. A first temperature detector 7 composed of, for example, a temperature-sensitive resistance element for detecting the temperature of the refrigerant on the side, and a second temperature detector 8 composed of, for example, a temperature-sensitive resistance element for detecting the temperature of the refrigerant on the outlet side of the evaporator 5
And each device is connected by a pipe 9 through which a refrigerant flows to form a refrigerant circulation path. Further, in this automotive air conditioner, the opening and closing of the motor-operated valve is controlled by the control device 10. The control device 10 can be configured by a microcomputer including an arithmetic unit 11, an input circuit 12, and an output circuit 13. Outputs of the first temperature detector 7 and the second temperature detector 8 are input to the input circuit 12, and a drive signal of the motor-operated valve 4 is output from the output circuit 13. The control device 10 calculates the flow rate of the refrigerant to be supplied to the evaporator 5 from the inlet temperature and the outlet temperature of the evaporator 5, and calculates the drive amount of the electric valve corresponding thereto. As the motor-operated valve 10 used in the refrigeration cycle of such an automotive air conditioner, a general motor-operated valve 4 driven by a stepping motor as shown in FIG.
Is used. The motor-operated valve 4 driven by the stepping motor includes an orifice 44 provided between a pipe 91 and a pipe 92 and a needle 43 rotated by a stepping motor 49. Needle 43
It is connected to a rotor 46 of a stepping motor 49 via a feed screw 45. The rotor 46 is driven and rotated by energizing a stator (drive winding) 48 provided outside a can 47 that separates the refrigeration cycle from the outside. The flow rate of the refrigerant flowing through the orifice is adjusted by driving the stepping motor 49 to move the needle 43 up and down in the axial direction to change the gap between the orifice 44 and the needle 43. The driving of such a stepping motor is as follows.
This is performed as follows. That is, FIG. 3 is a conceptual diagram showing an arrangement relationship between the rotor 46 of the stepping motor 49 and the drive winding 48. FIG. 4 is a chart showing the timing of the voltage applied to the drive winding 48. The stepping motor shown in FIG. 3 has four drive windings W _{1 to} W ₄ , the drive windings W ₁ and W ₂ have the same polarity, and the drive windings W ₃ and W ₄ have the other polarity. Of the same polarity. The timing of the drive pulse when the stepping motor is driven in two phases will be described with reference to FIG. Each drive winding W ₁ to _W-4,
Each driving pulse P ₁ to P ₄ is applied in a predetermined order according to the opening direction or closing direction of the valve. The rotor 46 made of a permanent magnet rotates in a predetermined direction by a rotation angle corresponding to the number of supply pulses. That is, at time t ₀ at the start, is first voltage to the winding W ₁ is applied, at time t _1, a voltage is applied to the windings W _1, W _2. Then the time t ₂ in winding W _2, W _3, the time t ₃ in winding W _3, W _4, a voltage is applied to the time t ₄ in winding W _4, W _1. Further, the time t at ₅ windings W _1, W _2, a voltage is applied i.e. in the same manner as the time t _1. Thereafter, by sequentially applying a voltage to the drive winding, the rotor 46 continues to rotate at a predetermined angle. By changing the voltage application sequence, the rotation direction of the rotor can be changed, and the opening and closing directions of the motor-operated valve can be controlled. The rotation of the rotor 48 causes the needle 43 to move up and down via the feed screw 45, and the gap between the needle valve 43 and the orifice 44 changes in proportion to the rotation angle. As a result, the flow rate of the refrigerant is controlled according to the pulse number, that is, the valve opening degree, as shown in the flow rate characteristic diagram shown in FIG. In this flow rate characteristic diagram, the horizontal axis indicates the pulse number, that is, the valve opening, and the vertical axis indicates the refrigerant flow rate (l / min). In the figure, a region A is a linear control unit which is controlled to perform a normal electric valve operation in which the flow rate changes in proportion to the valve opening degree, and a region B is a unidirectional refrigerant in which the valve is fully opened. This is the flow control area. Such a characteristic having an inflection point can be obtained by forming the tip of the needle 43 into a shape as shown in FIG. Hereinafter, a motor-operated valve having such a configuration is provided.
The operation of the refrigeration cycle of the automotive air conditioner will be described. First, a state when the cooling operation of the front seat system is performed will be described. At this time, the electric valve 4a of the front seat system is opened, the refrigerant flows to the refrigerant evaporator 5a, and the cooling of the front seat is performed. The temperature control of the cooling is performed by the controller 10 using the refrigerant inlet side temperature of the refrigerant evaporator 5a input from the first temperature detector 7a and the refrigerant evaporator 5a input from the second temperature detector 8a. Data on the valve opening calculated based on the refrigerant outlet temperature and other parameters such as room temperature and set temperature (in this case, rotation direction and number of pulses)
Is output to the drive stepping motor of the motor-operated valve 4a. That is, when increasing the flow rate of the refrigerant, a pulse in the order of increasing the valve opening is generated, and when decreasing the flow rate of the refrigerant, a pulse in the order of decreasing the valve opening is generated. In this state, when starting the cooling operation of the rear seat system, it is necessary to first open the electric valve 4b of the rear seat system. At this time, if the motor-operated valve 4b is opened rapidly, vibration noise is generated due to the pulsation of the refrigerant and abnormal pressure change as in the case of the solenoid valve. Therefore, the driving speed of the pulse motor is reduced, and the increase rate of the flow rate of the refrigerant is reduced. Must be loose. In the case of a pulse motor such as a stepping motor, the rotation speed can be controlled to an arbitrary value by controlling the applied pulse speed (frequency). When an air-conditioning operation start command is issued or a new system air-conditioning operation start command is issued, the rotation speed of the stepping motor is reduced by lowering and outputting the frequency of the drive pulse of the stepping motor for driving the electric valve, The opening speed of the valve is reduced to prevent the generation of vibration noise.
Hereinafter, the two systems can be operated by generating a pulse of a normal frequency for each system. Next, a description will be given of an operation in a case where the operation of one system is stopped when the two systems of the front system and the rear system are performing the cooling operation. The control device 10 that has received the command to stop the air-conditioning operation reduces the rotation speed of the stepping motor by lowering and outputting the frequency of the driving pulse of the stepping motor for driving the electric valve, as in the start of the operation, and closing the valve. Slow the speed to prevent the generation of vibration noise. Hereinafter, the remaining systems are operated by generating pulses of a normal frequency. The above control is performed by the arithmetic unit 11 of the control device 10.
Is being executed by the program stored in.
Therefore, the motor-operated valve 4 is controlled to open and close according to a predetermined program, and the refrigerant changes in the region A shown in FIG. 5, so that high-pressure refrigerant suddenly flows into the refrigerant evaporator or flows through the refrigerant evaporator. Will not be cut off abruptly. FIG. 7 is a view showing a main part of another embodiment of the motor-operated valve used in the present invention. The motor-operated valve is closed when the motor-operated valve is closed so that a predetermined amount of refrigerant can be secured even when the motor-operated valve is closed. 2 shows a configuration of a non-closing valve that is not performed. In the figure, it is an explanatory view showing the relationship between the valve element 43 and the orifice 44 in the closed state of the non-closing valve. In the present embodiment, as compared with the inside diameter H ₁ of the orifice 44, it is formed small outer diameter D ₁ of the valve body 43. Therefore, even when the valve body 43 is in the valve-closed state inserted into the orifice 44, the minimum flow path is formed, and the flow of a small amount of refrigerant is ensured. Valve element 43
By changing the taper angle of the tapered portion 51, the change in the flow rate that increases in proportion to the lift amount of the valve body can be selected. In the motor-operated valve of this embodiment, the characteristics shown in FIG. 8 can be obtained. Curve C ₁₂ shows the variation between the valve body 43 of the closed state is increased through the orifice 44 to lift L _2, during which the flow rate is constant without change from the predetermined flow rate Q _1. Curve C ₁₀ is lift indicates a change in the flow rate for the valve holder of the lift while the tapered portion 51 becomes L ₂ or more is gradually withdrawn from the valve seat 50 is proportional to the extraction cost of the valve body 43 And the flow rate increases. By using such an electric valve of the non-closing valve, the minimum flow rate can be ensured even when the flow rate is squeezed the most, so that the pressure in the pipe suddenly increases when the valve is closed. Can be reduced,
Vibration noise caused by water hammer development of the piping when the valve is closed can be further reduced. In the above description, the cooling operation is described. However, the heating operation is performed only by reversing the flowing direction of the refrigerant, so that it is possible to suppress the rapid change of the refrigerant. As described above, according to the present invention,
In a refrigeration cycle of an automotive air conditioner having a plurality of refrigerant evaporators, it is possible to slowly realize the inflow of the refrigerant into the refrigerant evaporator and to gradually shut off the flow of the refrigerant flowing in the refrigerant evaporator. So you can
Abnormal vibration noise can be effectively prevented. According to the present invention, the occurrence of abnormal vibration noise can be prevented without applying a soundproofing treatment to the piping, which is extremely effective for an air conditioner for an automobile for cooling or heating a very limited closed space. is there. Further, the present invention uses a small, electrically operated valve capable of freely controlling the opening / closing angle and the opening / closing speed instead of the conventional opening / closing means comprising an electromagnetic valve and an expansion valve, thereby reducing the energy consumption of the on / off valve. At the same time, the opening and closing valve is small and light, and the entire device can be reduced in size and weight, thereby contributing to improvement in the power performance and fuel efficiency of the automobile.

BRIEF DESCRIPTION OF THE DRAWINGS FIG. 1 is a conceptual diagram showing a configuration of a refrigeration cycle of an automotive air conditioner according to the present invention. FIG. 2 is a longitudinal sectional view showing a configuration of a motor-operated valve used in the present invention. FIG. 3 is a conceptual diagram showing the concept of the configuration of a stepping motor used in the present invention. FIG. 4 is a chart for explaining the timing of a drive pulse of a stepping motor used in the present invention. FIG. 5 is a characteristic diagram showing a relationship between an opening degree of an electric valve and a flow rate. FIG. 6 is a conceptual diagram showing a configuration of a refrigeration cycle of a conventional automotive air conditioner. FIG. 7 is an explanatory view showing a configuration of a main part of a motor-operated valve used in another embodiment of the present invention. FIG. 8 is a characteristic diagram illustrating operating characteristics of the motor-operated valve shown in FIG. [Description of Signs] 1 Compressor 2 Condenser 3 Liquid receiver 4 Motor-operated valve 5 Refrigerant evaporator 6 Receiver tank 7 First temperature detector 8 Second temperature detector 9, 91, 92 Piping 10 Control device 11 Operation Unit 12 Input circuit 13 Output circuit 41 Solenoid valve 42 Expansion valve 43 Needle (valve element) 44 Orifice 45 Screw part 46 Rotor 47 Can 48 Stator (drive winding) 49 Stepping motor 50 Valve seat 51 Tapered part

Claims (1)

(57) An automotive air conditioner having a refrigeration cycle having a plurality of refrigerant evaporators and supplying a refrigerant compressed by a compressor to each of the refrigerant evaporators is provided. An electric valve comprising an on-off valve for controlling the flow rate of refrigerant provided in a refrigerant pipe to a refrigerant evaporator and control means for controlling the on-off speed of the on-off valve, wherein the on-off valve is not completely closed. An air conditioner for a vehicle characterized by the above-mentioned.