Abstract: To provide an expansion valve having a low-pressure passage that is bent at right angles therein, which is reduced in untoward noise and noise of the flow of refrigerant generated when the refrigerant passes through the low-pressure passage. In an intersecting portion of a low-pressure passage, the axis of a port for introducing refrigerant returned from an evaporator, and the axis of a port for guiding out refrigerant having passed through a body block to a compressor are orthogonal to each other. A hole is formed in the body block in a direction of insertion of a shaft that transmits a driving force from a power element to a valve element, and a holder for holding the shaft.

Abstract: The object of the present invention is to provide a refrigeration cycle for an automotive air conditioner, which is reduced in costs and uses an ejector. A variable displacement compressor driven by an engine for driving an automotive vehicle is used as a compressor, and the capacity of the compressor is controlled by a capacity control valve such that the differential pressure between discharge pressure and suction pressure of refrigerant becomes equal to a predetermined differential pressure determined by an external signal. Pressure substantially equal to pressure applied across the compressor is applied across the ejector, and therefore to control the differential pressure across the compressor is to control the differential pressure across the ejector. A differential pressure valve disposed between a gas-liquid separator and an evaporator is set to a differential pressure approximately proportional to the differential pressure across the ejector.

Abstract: A four-way switching valve free from leakage of a refrigerant is disclosed. The valve includes two three-way switching valves arranged side by side, each having a pressure-regulating chamber, a piston, and a plug coaxially arranged. One of the pressure-regulating chambers selectively communicates with a low-pressure chamber or a high-pressure chamber via a three-way solenoid valve. The other pressure-regulating chamber communicates with another chamber in which the pressure increases or decreases as the pressure within one of the pressure-regulating chambers decreases or increases. As a result, refrigerant leakage is prevented, in turn preventing degradation of the refrigerating power of a system.

Abstract: A four-way switching valve includes a first three-way switching valve having a valve element for connecting a port B to a port A, or to a port D via a sleeve, in a switching manner; a second three-way switching valve having a valve element for connecting a port C to the port A, or to the port D, in a switching manner; and a piston for actuating these three-way switching valves. The three-way valves and piston are coaxially arranged within a hollow cylindrical body. A three-way solenoid valve introduces high pressure into a pressure chamber on the upper side of the piston to actuate the valve elements held on the sleeve downward, while the upward actuation is effected with a driving force produced by reducing the pressure in the pressure chamber and configuring guides to have a larger pressure-receiving area than that of a guide.

Abstract: The object of the present invention is to provide a method of controlling a refrigeration cycle such that maximum refrigerating capacity can be educed when the refrigeration cycle is started, the driving torque of a variable displacement compressor can be reduced when an automotive vehicle performs standing start or acceleration, and the refrigeration cycle can be operated with the maximum efficiency in a steady operating condition.

Abstract: To provide a small-sized and low-cost proportional solenoid valve which is capable of controlling a bidirectional fluid flow. A core is fixed in a pipe, and a hollow shaft having an extreme end thereof closed by a valve seat and a portion adjacent thereto formed with valve holes is fixed in the core. Within the pipe, there are arranged a hollow cylindrical valve element axially movable using the shaft as a guide and urged in a direction away from the core by a spring, for opening and closing the valve holes, and a plunger, while outside the pipe, there is arranged a solenoid coil. The proportional solenoid valve has a body formed by the pipe, and the component parts for opening and closing the valve are arranged within the pipe, so that it is possible to reduce the size of the proportional solenoid valve, the number of component parts, and machining costs and material costs, which contributes to reduction of costs of the valve.

Abstract: The object of the present invention is to provide a method of operating a refrigeration cycle which is capable of preventing oil from staying in an evaporator and ensures high coefficient of performance as well as sufficient circulation of oil. An electronic expansion valve is controlled such that during normal operation, refrigerant is always in a superheated state at the outlet of an evaporator, and the refrigerant is periodically forced to have negative superheat for a predetermined time by a superheat control device. Thus, during normal operation, the refrigerant sucked into a variable displacement compressor always has superheat, whereby the refrigeration cycle can operate with high coefficient of performance and an engine driving the variable displacement compressor can be operated at high fuel efficiency. Also, the refrigerant is temporarily controlled so as to have negative superheat.

Abstract: The object of the present invention is to prevent refrigerant from flowing out into a vehicle compartment due to damage to an evaporator or piping associated therewith. A solenoid valve is arranged at an inlet of an evaporator, and a check valve is arranged at an outlet of the evaporator. When operation of a system is to be stopped, the solenoid valve is closed while a compressor is kept operating for a predetermined time to suck out refrigerant from the evaporator to a downstream side of the check valve, so that during stoppage of the operation, the check valve prevents the refrigerant from flowing back into the evaporator. Thus, even if the evaporator arranged in the vehicle compartment or piping associated therewith is damaged, a situation where a large amount of refrigerant flows out of the evaporator into the vehicle compartment does not occur because no refrigerant remains in the evaporator, making it possible to prevent occupants in the vehicle compartment from being put in a grave situation.

Abstract: An object of the invention is to provide a variable displacement compressor which is capable of using a solenoid control valve which does not require a large solenoid force. The compressor is configured such that an electromagnetic proportional flow rate control valve is arranged in a refrigerant passage leading from a discharge chamber to a condenser, that a differential pressure regulating valve is arranged in a refrigerant passage leading from the discharge chamber to a crank chamber, and that a fixed orifice is arranged in a refrigerant passage leading from the crank chamber to a suction chamber, whereby the differential pressure regulating valve senses a differential pressure Pd, Pd′ generated across the electromagnetic proportional flow rate control valve, for control of pressure introduced into the crank chamber.

Abstract: The object of the present invention is to provide a control valve for a variable displacement compressor, which is capable of controlling the variable displacement compressor to the minimum capacity without using an electromagnetic clutch, and can be constructed without accommodating a solenoid in a pressure chamber. A plunger of a solenoid is formed by a first plunger and a second plunger, and a diaphragm is disposed between them, for sensing suction pressure Ps, such that the first plunger controls a valve element via a shaft, with component elements of the solenoid except for the first plunger being disposed on a side of the diaphragm where the atmospheric pressure is received. Further, when the solenoid is not energized, the high suction pressure Ps urges the second plunger toward the core via the diaphragm, and a spring causes the first plunger to urge the valve element to the fully open position, which enables the variable displacement compressor to be controlled to the minimum capacity.

Abstract: To provide a low-cost block-type expansion valve containing a strainer. A block-type expansion valve is configured such that a hollow cylindrical strainer is arranged in a space for introducing high-pressure liquid refrigerant, in a manner surrounding a valve element, and the refrigerant introduced into a refrigerant pipe-connecting hole is permitted to flow into a space on the upstream side of the valve element 17 via the strainer. Therefore, since the shape of a body is not substantially changed, it is possible to provide the expansion valve at low costs by suppressing an increase in the manufacturing costs to the cost of the strainer.

Abstract: The object of the present invention is to provide a solenoid valve-equipped expansion valve simplified in construction. A common valve element in which a valve element of an expansion valve and a valve element of a stop valve are integrally formed as a unitary member is disposed such that the common valve element can be axially movably guided by a shaft having the driving force of a power element transmitted thereto. A first core of a solenoid, holding the common valve element, is urged by a spring such that the common valve element is seated on a valve seat. When the solenoid is energized, the first core holding the common valve element is attracted by a second core rigidly fixed to the shaft such that the common valve element operates with the shaft in an interlocked fashion. As a result, when the solenoid is deenergized, the common valve element can function as a stop valve, whereas when the solenoid is energized, the common valve element can function as an expansion valve.

Abstract: The object of the present invention is to provide a capacity control valve for a variable displacement compressor that controls flow rate without the need for increased solenoid power. A compact, low-cost capacity control valve is provided as an integrated structure of a first control valve and a second control valve. The first control valve, placed on a passageway of refrigerant discharged from a variable displacement compressor, functions as a variable orifice whose cross-sectional area can be set as desired by varying the power of a solenoid unit. Part of the refrigerant discharged at pressure PdH is supplied to the crank chamber, in which the pressure is Pc. The second control valve controls this refrigerant flow to the crank chamber in such a way that the differential pressure between upstream pressure PdH and downstream pressure PdL of the discharged refrigerant will be regulated at a specified level.

Abstract: The object of the present invention is to provide a proportional valve which does not open or close by itself and is free of internal leakage. A valve element is formed integrally with a piston having a cross-sectional area equal to that of a valve hole constituting a valve seat, and a diaphragm having an outer peripheral portion secured to a body by a holder is disposed in contact with a pressure-receiving end face of the piston. The diaphragm is mounted in a displaced state such that when the valve element is seated on the valve seat, the pressure receiving area of the diaphragm is at a maximum and is equal to that of the valve element. Change in the pressure receiving area of the valve element corresponding to the lift amount thereof is canceled out by change in the pressure receiving area of the diaphragm corresponding to the amount of displacement thereof, thus preventing the valve from opening or closing by itself due to the difference between the pressure receiving areas.

Abstract: The object of the present invention is to provide a differential pressure control valve capable of preventing refrigerant from leaking along the outer periphery of a piston for actuating a main valve. An annular diaphragm has an inner peripheral edge portion clamped between a main valve piston and a fixing ring secured to the main valve piston, and an outer peripheral edge portion clamped between a body and a cylindrical member secured to the body, and the cylindrical member slidably receives the main valve piston. Thus, the outer periphery of the main valve piston is completely sealed by the diaphragm and inlet pressure P1 is introduced from a refrigerant introduction chamber into a piston chamber only through an orifice, whereby characteristics of the differential pressure control valve can be stabilized.

Abstract: A refrigerating cycle is capable of performing both an operation in which the maximum cooling power is desired to be unleashed and an operation in which the most excellent performance coefficient is attained. A refrigerating cycle is configured such that a differential pressure-regulating valve forming a pressure-reducing device is arranged between a condenser and a receiver. As a result, by setting the differential pressure regulated by the differential pressure-regulating valve 3 to 0, it is possible to cause the refrigerating cycle to perform an operation in which the maximum cooling power is desired to be unleashed, whereas by setting the same to a desired value, it is possible to cause the same to perform an operation in which an excellent performance coefficient is attained.

Abstract: The object of the present invention is to provide a constant flow rate expansion valve which is sufficiently reduced in leakage of refrigerant. A constant flow rate expansion valve includes a refrigerant passage having a fixed flow path cross-sectional area smaller than that of a refrigerant inlet, a differential pressure control valve for controlling the differential pressure (P1−P2) between an inlet pressure P1 and an intermediate pressure P2 generated by refrigerant flowing through the refrigerant passage to be constant, and a solenoid capable of setting the differential pressure by the value of an electric current externally supplied. In the differential pressure control valve, a piston and a valve element integrally formed with each other sense the differential pressure (P1−P2), change a gap between the valve element and a valve seat such that the differential pressure is held constant, and adiabatically expand the refrigerant at the gap.

Abstract: The object of the present invention is to provide a method of controlling a refrigeration cycle such that maximum refrigerating capacity can be educed when the refrigeration cycle is started, the driving torque of a variable displacement compressor can be reduced when an automotive vehicle performs standing start or acceleration, and the refrigeration cycle can be operated with the maximum efficiency in a steady operating condition.

Abstract: A displacement control valve which is capable of shortening a time period for transition in operating displacement, and operating without necessitating a large solenoid force even if the size of the valve is increased so as to increase the amount of refrigerant. A differential pressure-sensing section is separated from a valve section, and caused to sense the differential pressure by a small-diameter piston rod such that even a small-sized solenoid section can set a differential pressure. A valve element, which is formed to have a larger diameter than that of the piston rod to increase the amount of refrigerant, is configured to operate as a member formed in one piece with a shaft.

Abstract: A displacement control valve that performs transition between operating capacities in a reduced time period. A valve element for introducing refrigerant from a discharge chamber into a pressure-regulating chamber after reducing discharge pressure Pd of the refrigerant to pressure Pc1, and a valve element for introducing refrigerant having pressure Pc2 from the pressure-regulating chamber into a suction chamber under suction pressure Ps are configured to open and close in an interlocked fashion, and a displacement control valve is comprised of the valve elements and a solenoid section that applies to a solenoid force corresponding to a predetermined differential pressure to these valve elements.