Abstract: In a thermal fluid system, a control valve includes a flow valve and a solenoid pilot valve. The flow valve has an inlet and an outlet; a control chamber for receiving a pilot pressure; and a valve member operable by the pilot pressure to selectively open and close a fluid path from the inlet to the outlet. The pilot pressure acts in a closing direction of the flow valve. The pilot valve provides the pilot pressure to the control chamber and is a 3/2 way valve with a first port in fluid communication with the control chamber, a second port to be connected to a pressure source, and a third port. The pilot valve has a first position connecting the first port with the second port and a second position connecting the first port with the third port.

Abstract: In a thermal fluid system, a control valve includes a flow valve and a solenoid pilot valve. The flow valve has an inlet and an outlet; a control chamber for receiving a pilot pressure; and a valve member operable by the pilot pressure to selectively open and close a fluid path from the inlet to the outlet. The pilot pressure acts in a closing direction of the flow valve. The pilot valve provides the pilot pressure to the control chamber and is a 3/2 way valve with a first port in fluid communication with the control chamber, a second port to be connected to a pressure source, and a third port. The pilot valve has a first position connecting the first port with the second port and a second position connecting the first port with the third port.

Abstract: A heating, ventilation, and air conditioning (HVAC) system and a method of controlling a HVAC system that is configured to provide a perceived comfortable ambient environment to an occupant seated in a vehicle cabin. The system includes a nozzle configured to direct an air stream from the HVAC system to the location of a thermally sensitive portion of the body of the occupant. The system also includes a controller configured to determine an air stream temperature and an air stream flow rate necessary to establish the desired heat supply rate for the sensitive portion and provide a comfortable thermal environment by thermally isolating the occupant from the ambient vehicle cabin temperature. The system may include a sensor to determine the location of the sensitive portion. The nozzle may include a thermoelectric device to heat or cool the air stream.

Abstract: An internal heat exchanger assembly for an air conditioning system, having a substantial cylindrical cavity in which a helical coil tube is coaxially disposed within the cylindrical cavity. A bleed valve assembly is incorporated into the helical coiled tube, in which the bleed valve assembly is adapted to open at a predetermined differential pressure between the high pressure side and low pressure side of the internal heat exchanger. The bleed valve selectively bleeds refrigerant from the high pressure side to the low pressure side, thereby increasing the pressure and mass flow rate of the refrigerant to the suction side of a compressor.

Abstract: A vehicle air conditioner system having, and method of operating, an externally controlled variable displacement compressor and a compressor clutch. If the system is operating during conditions when the operating displacement is low, the efficiency of the system is increased by duty cycling the clutch. Operating an externally controlled variable displacement compressor in this manner can also prevent overcooling by the air conditioner.

Abstract: A heating, ventilation, and air conditioning (HVAC) system and a method of controlling a HVAC system that is configured to provide a perceived comfortable ambient environment to an occupant seated in a vehicle cabin. The system includes a nozzle configured to direct an air stream from the HVAC system to the location of a thermally sensitive portion of the body of the occupant. The system also includes a controller configured to determine an air stream temperature and an air stream flow rate necessary to establish the desired heat supply rate for the sensitive portion and provide a comfortable thermal environment by thermally isolating the occupant from the ambient vehicle cabin temperature. The system may include a sensor to determine the location of the sensitive portion. The nozzle may include a thermoelectric device to heat or cool the air stream.

Abstract: An internal heat exchanger assembly for an air conditioning system, having a substantial cylindrical cavity in which a helical coil tube is coaxially disposed within the cylindrical cavity. A bleed valve assembly is incorporated into the helical coiled tube, in which the bleed valve assembly is adapted to open at a predetermined differential pressure between the high pressure side and low pressure side of the internal heat exchanger. The bleed valve selectively bleeds refrigerant from the high pressure side to the low pressure side, thereby increasing the pressure and mass flow rate of the refrigerant to the suction side of a compressor to reduce or eliminate compressor rattle.

Abstract: An exhaust gas heat recovery (EGHR) heat exchanger for an internal combustion engine having a housing, a cylindrical body disposed within the housing, an annular exhaust gas passageway, and a central exhaust gas passageway. The EGHR heat exchanger also includes a bypass valve disposed within the central passageway and adapted to selectively by-pass a portion of the exhaust gas from the central exhaust gas passageway to the annular passageway, and at least one twisted tube having at least one edge coiled within the annular exhaust gas passageway.

Abstract: A control methodology for dynamically adjusting the switching limits of a cycled refrigerant compressor in an air conditioning system with the objective of achieving an optimal or specified tradeoff between compressor cycling frequency and discharge air temperature variation under all operating conditions. In a first embodiment, the compressor cycling limits are controlled to maintain a virtually constant discharge air temperature variation for all operating conditions. In a second embodiment, the compressor cycling limits are controlled so that the discharge air temperature variation changes in relation to the discharge air temperature to provide a virtually constant human comfort level for the occupants. And in a third embodiment, the compressor cycling limits are controlled so that the discharge air temperature variation changes in relation to the ambient or outside air temperature to provide a virtually constant human comfort level for the occupants.

Abstract: A vehicle air conditioner system having, and method of operating, an externally controlled variable displacement compressor and a compressor clutch. If the system is operating during conditions when the operating displacement is low, the efficiency of the system is increased by duty cycling the clutch. Operating an externally controlled variable displacement compressor in this manner can also prevent overcooling by the air conditioner.

Abstract: A cylindrical stainless steel housing includes an exhaust inlet collar and exhaust outlet collar allowing exhaust gas to travel therethrough at a mean flow velocity in accordance with a velocity formula. A plurality of stainless steel tubes extend through the housing from a steam inlet manifold to a steam outlet manifold. A number and size of the tubes is determined by formulas and dependent on an Euler number, a Reynolds number, a number of transfer units, a Prandtl number, a porosity factor and a system efficiency. The tubes may comprise an S-shape or a U-shape. The tube walls have a thickness determined according to wall thickness formulas and the walls include a plurality of cavities on an interior surface of each tube wall. The cavities may comprise a conical or semi-spherical shape and have a diameter determined according to formulas.

Abstract: A method for heating ambient air for a passenger compartment of a motor vehicle is disclosed herein. The method includes the step of positioning a first heat exchanger proximate to a passenger compartment of a vehicle. The method also includes the step of passing ambient air for the passenger compartment through a first heat exchanger. The method also includes the step of concurrently directing distinct flows of engine coolant and steam to the first heat exchanger to heat the ambient air.

Abstract: A control methodology for dynamically adjusting the switching limits of a cycled refrigerant compressor in an air conditioning system with the objective of achieving an optimal or specified tradeoff between compressor cycling frequency and discharge air temperature variation under all operating conditions. In a first embodiment, the compressor cycling limits are controlled to maintain a virtually constant discharge air temperature variation for all operating conditions. In a second embodiment, the compressor cycling limits are controlled so that the discharge air temperature variation changes in relation to the discharge air temperature to provide a virtually constant human comfort level for the occupants. And in a third embodiment, the compressor cycling limits are controlled so that the discharge air temperature variation changes in relation to the ambient or outside air temperature to provide a virtually constant human comfort level for the occupants.

Abstract: A high efficiency air conditioning system includes a pneumatically-controlled variable displacement compressor and a compressor clutch that is selectively cycled on and off to minimize series re-heating of conditioned air. Conditioned air is discharged after passing through an evaporator core, and a target value for the evaporator outlet air temperature is determined based on the desired air discharge temperature. The compressor clutch is cycled off when the evaporator outlet air temperature falls below the target value by at least a calibrated amount, and is thereafter cycled on again when the evaporator outlet air temperature rises above the target value. The target value is preferably biased to prevent compressor operation when the desired air discharge temperature exceeds outside air temperature by at least a calibrated amount and to prevent the relative humidity in the air-conditioned space from rising above a desired level.

Abstract: A method of operating a directed relief valve (28) for an air conditioning system (10) preferably for a vehicle. The air conditioning system (10) includes a compressor (12), a condenser (16), an expansion device (20), and an evaporator connected to one another by refrigerant lines. The system (10) also includes the directed relief valve (28), which is disposed inline with at least one of the refrigerant lines to ventilate the refrigerant. The directed relief valve (28) includes a detonable squib (36) that explodes in response to a ventilation signal. A controller (40) generates the ventilation signal in response to a refrigerant leak being detected by a sensor (38). The sensor (38) is preferably located within an air space (27) and adjacent to the evaporator (22). If there is a malfunction of one of a plurality of sensors (38), a partial malfunction message is sent to the operator.