Abstract: In a control valve for a variable displacement compressor, for controlling the discharge flow rate of refrigerant to be constant, to dispense with a check valve in a refrigerant outlet port of the compressor. The control valve includes a first control valve that controls the passage cross-sectional area of a refrigerant passage through which refrigerant passes from a discharge chamber of the compressor to a refrigerant outlet port thereof, and a second control valve that controls the flow rate of refrigerant allowed to flow from the discharge chamber to a crankcase such that a differential pressure (Pdh?Pdl) across the first control valve generated by the refrigerant passing therethrough becomes constant. The control valve is configured such that when a solenoid section is not energized, a first valve element is engaged with a piston to forcibly fully open the second control valve.

Abstract: A variable displacement compressor driven by an engine, such as 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: The object is to provide a capacity control valve for a variable displacement compressor, which is not adversely affected by pressure from a pressure-regulating chamber. The cross-sectional area of a valve hole of a high pressure-side valve seat for introducing discharge pressure Pd of a variable displacement compressor into a pressure-regulating chamber is A, the cross-sectional area of a valve hole of a low pressure-side valve seat for introducing pressure Pc1 (=Pc2) of the pressure-regulating chamber into a suction chamber is B, and the average cross-sectional area of a refrigerant passage assumed when a low-pressure valve element is open during most of control time of actual operation is b. A and B are set to A<B to make the effective pressure receiving area (?A) of the high pressure-side valve and the effective pressure receiving area (?B?b) of the low pressure-side valve approximately equal.

Abstract: To provide a fluid control valve which is capable of preventing or suppressing degradation of the accuracy of flow rate control dependent on the lift amount of a valve element from a valve seat. An expansion valve is configured such that a valve portion and a valve portion integrally formed with a valve element move to and away from a valve seat and a valve seat, respectively, simultaneously. Further, the expansion valve is configured such that a flow passage cross-section formed by a gap between the valve portion and the valve seat, and a flow passage cross-section formed by a gap between the valve portion and the valve seat have approximately the same size when the expansion valve is open.

Abstract: To reduce the degree of influence of differential pressure on a pilot valve of a constant flow rate expansion valve. The constant flow rate expansion valve comprises a restriction passage for restricting the flow rate of refrigerant introduced from a refrigerant inlet port, a main valve for controlling the flow rate of refrigerant having flowed out from the restriction passage for discharging the refrigerant to a refrigerant outlet port, a piston for actuating the main valve in the valve-opening/closing direction by the differential pressure between intermediate pressure on the inlet port side of the main valve and pressure in a pressure chamber formed on the opposite side of the main valve, and a pilot valve for sensing the differential pressure proportional to the flow rate of refrigerant flowing through the restriction passage, thereby controlling the pressure in the pressure chamber set by a solenoid.

Abstract: To enable a control valve for a variable displacement compressor, which operates by sensing a differential pressure between discharge pressure and suction pressure or between the discharge pressure and crankcase pressure, to enhance compression efficiency inside the compressor. In the control valve for a variable displacement compressor, according to the present invention, after a valve element on a high pressure side closes a valve hole, a valve element on a low pressure side opens a valve hole. Therefore, it is possible to eliminate a region in which both the valves on the high pressure side and the low pressure side are simultaneously open. This makes it possible to prevent refrigerant introduced into a crankcase from being immediately delivered, which makes it possible to obtain a sufficient compression efficient.

Abstract: To provide a control valve for a variable displacement compressor, which is capable of stably operating in a pressure control area, and causing the compressor to quickly shift to operation with the minimum displacement. The control valve for a variable displacement compressor is capable of realizing stable pressure control, since a force applied to a valve element in a valve-closing direction increases when the valve element is in a pressure control area, and is balanced with a force applied to the valve element in a valve-opening direction by the pressure of refrigerant. Further, when the valve element moves past an end point of the pressure control area, the force applied to the valve element in the valve-closing direction decreases to thereby increase the valve-opening degree of a valve portion when the valve portion is fully open.

Abstract: To provide a low-cost expansion device which is capable of changing a passage cross-sectional area of a restriction passage according to the pressure and temperature of introduced refrigerant, without provision of a high-pressure hermetically sealed space. The expansion device comprises a differential pressure valve for having the valve lift thereof controlled according to the differential pressure across the expansion device, and a temperature-sensing section for further controlling the valve lift of the differential pressure valve according to the temperature of refrigerant. The differential pressure valve includes a piston that has a larger outer diameter than that of a valve element and is integrally formed with the valve element.

Abstract: To provide a constant differential pressure valve which is compact in size and can be realized at low cost. In the constant differential pressure valve according to the present invention, a pipe forming a body thereof not only accommodates internal structures, such as a differential pressure control mechanism, a movable core, and a fixed core, but also serves as part of piping of a refrigeration cycle. Further, a solenoid section including a solenoid coil is disposed outside the pipe in a manner surrounding the same. Therefore, substantial integration of the differential pressure control mechanism into the piping of the refrigeration cycle can be achieved, which makes the entire constant differential pressure valve very simple in construction. As a result, reduction of the size of the constant differential pressure valve and resultant reduction of material costs and manufacturing costs can be achieved, which makes it possible to achieve low costs of the constant differential pressure valve.

Abstract: 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 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: 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 capacity control valve for a variable displacement compressor, which is not adversely affected by pressure from a pressure-regulating chamber. A three-way valve structure is formed in which a high-pressure valve element and a low-pressure valve element are integrally formed at both ends, and valve seats with valve holes having the same diameter are arranged in a manner opposed to the respective valve elements. A discharges pressure is supplied from the upstream side of the valve seat, and a suction pressure is supplied from the downstream side of the valve seat. Pressures from a pressure-regulating chamber are received at the downstream side of the high-pressure valve element and the upstream side of the low-pressure valve element.

Abstract: A small sized and structurally simple capacity controller having a wide control range of a compressor with variable capacity adds a differential pressure to an inhalation pressure on an arbitrary level by a piston valve body actuated by a solenoid and by the inhalation pressure. The differential pressure is transmitted into a capacity variation mechanism of the compressor in order to change the capacity of the compressor.

Abstract: To provide a control valve for use in a variable displacement compressor, for fixed flow rate control, which can be constructed compact in size without necessitating pressure sensors for detecting a differential pressure. The control valve comprises a first valve having configuration of a check valve that opens and closes by the differential pressure between discharge pressure from a discharge chamber and discharge pressure at an outlet port of the compressor, a second valve that opens and closes by sensing the differential pressure between the discharge pressure Pdh and pressure in the crankcase, and a solenoid that sets the differential pressure across the first valve. The motion of a valve element of the first valve is transmitted to a valve element of the second valve via a shaft.

Abstract: To provide a control valve for a variable displacement compressor, which is capable of promptly restoring a high-sensitivity variable displacement compressor to a predetermined discharge capacity without causing hunting even when the rotational speed of the compressor is rapidly changed. A valve section controls the flow rate of refrigerant flowing from a discharge chamber to a crankcase, based on the differential pressure between discharge pressure and suction pressure.

Abstract: To provide a control valve for a variable displacement compressor, which is capable of promptly restoring the compressor to a predetermined discharge capacity even when the rotational speed of an engine is rapidly changed. In a valve section for controlling the flow rate of refrigerant flowing from a discharge chamber into a crankcase of a variable displacement compressor, a pressure-sensing section is provided in a high-pressure port that receives discharge pressure. In the pressure-sensing section, when a pressure-sensing piston which is larger in pressure-receiving area than a valve element receives a change in discharge pressure caused by a rapid change in rotational speed of the engine, differential pressure is produced between discharge pressure Pd and pressure in a pressure-adjusting chamber, which temporarily produces a force for axially moving the piston.

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: 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: To provide a refrigerant relief device capable of operating reliably by a simple construction without causing leakage of refrigerant. A refrigerant-introducing chamber defined in a body that forms a joint for connection to piping of a refrigeration cycle, and an open-to-atmosphere chamber communicating with the atmosphere via openings are isolated by a metal thin film from each other, and the metal thin film is welded to the body to prevent leakage of refrigerant. The metal thin film receiving refrigerant pressure is held by a belleville spring. When the refrigerant pressure becomes higher than a set pressure, the belleville spring is inverted in shape to displace the metal thin film toward the open-to-atmosphere chamber. A piercing rod is disposed at a location where the metal thin film is displaced. The piercing rod breaks the metal thin film, and releases refrigerant in the refrigeration cycle into the atmosphere to thereby suddenly decrease the refrigerant pressure.