JPS6217555A - Cooling system for vehicle - Google Patents

Abstract

PURPOSE:To avoid the degradation of driving comfortableness by causing the open/close valve to switch the intake port by a control signal so as to modulate the refrigerant delivery rate of compressor. CONSTITUTION:When the sensor 11 detects that the air temperature in the passenger compartment is lower than the predetermined temperature, the open/ close valve 13 moves to close one of the intake ports of compressor 2 based on the operational command controlled by the control unit 12 to reduce the refrigerant delivery rate of compressor 2 by half. In the refrigerating cycle under this condition, the amount of refrigerant supplied to the evaporator 6 is reduced. As a result, the cooling capacity per unit time is reduced, and the time period in which the temperature drops to the predetermined temperature becomes longer. In this time period, the compressor 2 will not stop its operation due to the disengagement of the electromagnetic clutch 4 based on the signal from the air temperature sensor 7. Therefore, there is less repetition of ON-OFF operation of the compressor side electromagnetic clutch, and so, the change of engine load becomes smoother, which improves the driving comfortableness.

Description

[Detailed description of the invention] (Industrial application field) The present invention relates to a vehicle cooling device.

(Prior Art) Conventionally, this type of vehicle cooling system uses a refrigeration cycle system in which the discharge capacity of a refrigerant such as Freon gas compressed by an engine-driven compressor is set at a constant rate. According to this, in order to prevent the interior of the vehicle from becoming too cold due to the cooling air blown out from the evaporator, the electromagnetic clutch on the compressor side is automatically or artificially activated when the interior air falls to a predetermined cooling temperature. Turn OFF to stop compressor operation. When the temperature of the air inside the vehicle rises to a predetermined temperature again, the electromagnetic clutch is turned on to operate the compressor and start cooling.

(Problem to be Solved by the Invention) However, in the case of such a device, the discharge capacity of the refrigerant is constant regardless of environmental changes due to temperature and humidity inside and outside the vehicle. So,
Since the refrigerant discharge capacity becomes excessive (the cooling capacity is excessive), the air inside the vehicle is cooled faster. As a result, the frequency of repeated activation and deactivation of the compressor increases due to the ON and OFF operation of the electromagnetic clutch, and the engine load fluctuates each time, causing a phenomenon similar to knocking and significantly deteriorating the driving feeling. There are some problems.

(Means for Solving the Problems) In order to solve the above-mentioned problems, a vehicle cooling system according to the present invention is provided with a cooling system that reduces the temperature of the air discharged from the discharge port side of the evaporator into the vehicle interior after being cooled. A vehicle cooling system is provided with a compressor that stops operating when an electromagnetic clutch is released when a predetermined temperature is reached, and the air conditioner is installed on the vehicle interior air intake side of the evaporator to control wind humidity, wind humidity, or air volume. detection means for detecting at least one of the following;
The compressor includes an on-off valve provided at a suction port in the compressor to open and close the suction port, and a control unit that outputs a signal to the on-off valve based on a detection signal from the detection means, Alternatively, when any one of the air volume reaches a predetermined value, or when wind humidity or enthalpy determined by wind humidity or air volume reaches a predetermined value, the on-off valve is activated by a control signal from the control unit to the suction port. The refrigerant discharge capacity of the compressor is changed by operating in the direction of switching the refrigerant discharge capacity of the compressor.

As a result, the present invention automatically reduces the refrigerant discharge capacity in an environment where the temperature and humidity of the air inside and outside the vehicle are low, that is, when the amount of heat held in the air at that time is small. By lowering the cooling capacity relative to the amount of retained heat, cooling is accelerated and the frequency of repeated activation and deactivation of the compressor can be reduced, and a suitable running feeling can be obtained.

(Example) Hereinafter, an example of a vehicle cooling device according to the present invention will be described with reference to the drawings.

In FIG. 1, 1 is an engine, 2 is a compressor to which the drive of the engine 1 is transmitted via a transmission belt 3, and 4 is an electromagnetic clutch that connects and disconnects the drive from the engine to the compressor 2. In addition, 5 is a condenser that cools and liquefies refrigerant such as Freon gas that has been compressed by the compressor 2 and becomes high temperature and high pressure, and 6 is a condenser that evaporates the liquefied refrigerant sent from this condenser 5 and An evaporator that removes heat from air and converts it into a gas.

The refrigerant gasified by the evaporator 6 is sucked into the compressor 2 again, and this series of refrigeration cycles is repeated to continue removing heat from the air inside the vehicle, thereby lowering the temperature and humidity. Also,
Reference numeral 7 denotes an air temperature detector installed on the cooling air outlet side of the evaporator 6, which detects when the cooling temperature when the cooled vehicle interior air is discharged falls below a predetermined value and sends the control unit to the control unit. A control signal is input to the electromagnetic clutch 4 from the electromagnetic clutch 12, and power to the electromagnetic clutch 4 is cut off to turn it into an OFF state, and the compressor 2 stops operating. This air temperature detector 7 is also installed in conventional devices.

In the figure, 8 is a liquid tank that separates the refrigerant liquefied by the condenser 5 into gas and liquid, 9 is an expansion valve, and 10 is an electric fan 8 (air blower) that sends air from inside the vehicle to the evaporator 6.

On the other hand, on the cabin air intake side of the evaporator 6, a fin (not shown) installed on the evaporator 6 is provided.
A detector 11 that detects at least one of air temperature, air temperature, and air volume is installed in the passage between the two. 12 is the detector 11
The signal controlled by the control unit 12 is sent to the on-off valve 13 for opening and closing the suction port, which will be described later, provided on the compressor 2 side. As the detector 11 for detecting the wind temperature, for example, there is a thermistor temperature sensor. For air temperature detection, for example, there is a moisture-sensitive resistor made of a porous sintered body of a metal oxide mainly composed of A1t03. For example, a hot wire flow meter is used to detect the air flow rate, but it is also possible to use a simple method that detects the position of the fan switch or fan motor voltage for controlling the air flow rate using the proa fan of the current vehicle air conditioner. It is.

Here, the structure of the compressor 2 employed in the embodiment will be schematically explained with reference to FIGS. 2 to 4.

In this compressor 2, a cam ring 20 having a substantially elliptical cam surface 20a is sealed with front and rear plates 21 and 22 from both sides in the axial direction, and a rotor 23 is rotatably housed inside the cam ring 20. A vane 25 is fitted into a radial slit 24 formed in the rotor 23 so as to be freely retractable. A back pressure passage 26 is formed at the bottom of each slit 24 , and each back pressure passage 26 communicates with a communication hole 27 formed in the rotor 23 . Lubricating oil is supplied. In the space between the cam ring 20 and the rotor 23, a pump chamber 28 is defined by adjacent vanes 25. 2 in this pump chamber 28
A refrigerant such as Freon gas is sucked in from the two suction ports 1-Pl and Pz, and the vane 25 is pressed against the cam surface 20a by the centrifugal force accompanying the rotation of the rotor 23 and the pressure of lubricating oil in the back pressure passage 26 (vane back pressure). It slides into contact and rotates. As a result, the refrigerant is compressed and the corresponding discharge bow) S+, St
It will be discharged from The suction boats P1 and Pt are formed at equal intervals (180° apart) in the circumferential direction of the cam ring 20. For example, as shown in FIGS. 3 and 4, one suction boat Pt is equipped with an on-off valve 13 such as a solenoid valve, and a control signal from the control unit 12 shown in FIG. When input to the valve 13, it operates in the direction of closing the suction boat P2 (see FIG. 3).

Next, the effect will be explained.

The engine l is driven by the input switch of the electromagnetic clutch 4.
With the N operation, the air is transmitted to the vane type rotary compressor 2 to start cooling. The refrigerant compressed by the vane-type rotary compressor 2 is cooled and liquefied by the condenser 5, and then vaporized by the evaporator 6, which removes heat from the air inside the vehicle and cools it. At this time, when the detector 11 provided between the wind guide fins on the side of the cabin air intake port of the evaporator 6 is used as a wind temperature sensor to detect the wind temperature of the cabin air blown by the electric fan IO, When it is detected that the current wind temperature of the air inside the vehicle is below a predetermined value, one suction boat Pz in the compressor 2 is closed based on an operation command controlled by the control unit 12 based on this detection signal. The on-off valve 13 operates in the direction. That is, the suction boat Pz is closed by the operation of the control unit 12 (see FIG. 3), and the discharge capacity of the refrigerant in the compressor 2 is halved, for example, by 50% of the capacity when the suction boat Pt is fully open.

However, the refrigerant discharge capacity is not limited to being halved, and the reduction ratio can be set to various values by adjusting the opening/closing degree of the suction boat Pz.

In this way, in the refrigeration cycle in which the refrigerant discharge capacity from the compressor 2 is halved, the amount of refrigerant sent to the evaporator 6 decreases, and the cooling capacity per hour decreases. Naturally, the time it takes for the temperature to reach a predetermined temperature is longer than in the conventional case, and during this time, based on the detection signal from the air temperature detector 7, the compressor 2 is stopped by turning off the magnetic clutch 4. Never. That is, when the cooling of the cabin air progresses from the state where the refrigerant discharge capacity is halved, and the cooling temperature on the discharge port side of the evaporator 6 falls to a predetermined value,
The air temperature detector 7 detects this, and the electromagnetic clutch 4 is first turned off based on this detection signal.

In the embodiment, the detector 11 has been described as a wind temperature sensor, but it may also be a sensor that detects either wind humidity or air volume, or a sensor that detects all of the above, including wind temperature. It is also possible.

(Effects of the Invention) As can be understood from the above, the vehicle cooling system according to the present invention provides a means for detecting wind temperature, etc., on the interior air intake side of the evaporator. In response to environmental changes such as when the air temperature is low, the refrigerant discharge capacity is reduced by halving or otherwise, and the heat load on the evaporator is reduced, and the cooling temperature at the evaporator discharge port is reduced. The time required to reach the specified temperature is longer than that of conventional products, so
The repeating frequency of ON/OFF of the electromagnetic clutch on the compressor side is reduced, so fluctuations in engine load are smoothed out, and driving feeling is significantly improved.

[Brief explanation of the drawing]

FIG. 1 is an overall view of an embodiment of a vehicle cooling device according to the present invention, and FIGS. 2 to 4 are a front sectional view and a side sectional view taken along the Y-Y line of the compressor adopted in the device of the embodiment. and a structural diagram of main parts. 2... Compressor, 4... Electromagnetic clutch, 5... Capacitor, 6... Evaporator, 11... Detector (detection means ), 12...
・Control TJ unit, 13...Opening/closing valve, P2...Suction boat.

Claims (1)

[Claims] A vehicle cooling system comprising a compressor that releases an electromagnetic clutch and stops operating when the temperature of cooled air discharged into a vehicle interior from the discharge port side of an evaporator reaches a predetermined temperature, a detection means provided on the cabin air intake side of the evaporator to detect at least one of wind temperature, wind humidity, or air volume; and an on-off valve provided at the suction port of the compressor to open and close the suction port. , a control unit that outputs a signal to the on-off valve based on the detection signal from the detection means, and when any one of the wind temperature, wind humidity, or air volume reaches a predetermined value, or the wind temperature or wind When enthalpy determined by humidity or air volume reaches a predetermined value, the on-off valve operates in a direction to switch the suction port in response to a control signal from the control unit, thereby changing the refrigerant discharge capacity of the compressor. A vehicle cooling system featuring: