Abstract: An integrated capacity control valve for a variable capacity refrigerant compressor includes an integral pressure sensor that is continuously coupled to a discharge port of the valve for measuring the refrigerant discharge pressure. A plunger of the control valve is disposed within a passage coupling the compressor crankcase to the discharge port, and is positioned by pneumatic and electric control elements to regulate the refrigerant suction pressure. The plunger has intersecting axial and lateral bores that define a continuous passage between the discharge port and a cavity in which the pressure sensor is retained so that the sensor is continuously exposed to the discharge pressure regardless of the plunger position, and refrigerant discharge pressure in the lateral bore produces a bias force on the plunger that compensates the pneumatic suction pressure setpoint for a pressure drop between the evaporator and the suction port of the valve.

Abstract: A pneumatically-operated control valve selectively opens and closes a passage between discharge and crankcase chambers of a variable capacity refrigerant compressor for purposes of controlling the compressor capacity, and includes an integral pressure sensor for measuring the compressor discharge pressure. The valve includes a plunger having an axis, a stopper biased against a seat in the passage coupling the discharge and crankcase chambers, an annular bellows and a pressure sensor. A portion of the plunger passes through the annular bellows, and one end of the bellows is attached to the plunger for axially displacing the plunger to unseat the stopper. The stopper and plunger are maintained in engagement, and have axial bores that are aligned to form a passage between the compressor discharge chamber and a cavity in which the pressure sensor is retained.

Abstract: An improved HVAC control method immediately closes an air inlet valve to provide full cabin air recirculation when an outside air quality sensor detects polluted air, and thereafter progressively re-opens the air inlet valve at a determined rate when the air quality sensor detects unpolluted air. Preferably, the air quality sensor quantifies the pollution level of the outside air, and the opening rate of the air inlet valve is determined based on the detected pollution level. Following a high level of detected air pollution, the valve is re-opened at a relatively slow rate, and following a low level of detected air pollution, the valve is re-opened at a relatively fast rate.

Abstract: An improved HVAC control method immediately closes an air inlet valve to provide full cabin air recirculation when an outside air quality sensor detects polluted air, and thereafter progressively re-opens the air inlet valve at a determined rate when the air quality sensor detects unpolluted air. Preferably, the air quality sensor quantifies the pollution level of the outside air, and the opening rate of the air inlet valve is determined based on the detected pollution level. Following a high level of detected air pollution, the valve is re-opened at a relatively slow rate, and following a low level of detected air pollution, the valve is re-opened at a relatively fast rate.

Abstract: An air quality system for controlling air quality in a cabin of a vehicle is provided. The air quality system utilizes three air quality sensors for detecting three air quality parameters. A controller is responsive to the air quality sensors. The controller is programmed to determine a current value of the air quality parameters from the air quality sensors and to determine whether the current value of any of the air quality parameters exceeds a predetermined limit. The predetermined limits for the air quality parameters are based on levels indicative of poor air quality for the cabin. The controller is operable between purging and non-purging modes to purge the air from the cabin in the purging mode when the current value of any of the measured air quality parameters exceeds the respective predetermined limit.

Abstract: A manually controlled motor vehicle HVAC system is activated for automatically pre-heating or pre-cooling the cabin following remote starting of the vehicle engine. When the engine has been remotely started, an HVAC controller estimates initial outside air and cabin air temperatures, and determines if pre-heating or pre-cooling is appropriate based on the estimated initial temperatures, the engine coolant temperature and a measure of the engine soak time. When pre-heating or pre-cooling is deemed to be appropriate, the HVAC parameters normally set by a driver interface panel are selectively overridden based on the estimated initial outside air and cabin air temperatures. In a particularly advantageous embodiment, the initial outside air temperature is estimated based on an inlet air temperature sensor of the engine or on a refrigerant pressure sensor of the HVAC system prior to activation of the refrigerant compressor.

Abstract: A heating, venting, and air conditioning system utilizes a reformer to provide supplemental heat to a passenger compartment and to improve start-up emissions of an engine of a vehicle or power system. A pump circulates a fluid through the engine and throughout the system. A radiator and heater core transfer heat from the fluid. A first circuit cools the fluid upon circulation through the radiator after circulation through the engine to cool the engine, and a second circuit heats the passenger compartment and cools the fluid upon circulation through the heater core after circulation through the engine to cool the engine. The reformer, which converts a hydrocarbon or alcohol fuel into a reformate, generates heat. A third circuit, defined between the reformer and the pump and interconnected with the heater core, provides the supplemental heat from the reformer to the passenger compartment through the heater core and also to the engine.

Abstract: A heating, venting, and air conditioning system utilizes a reformer to provide supplemental heat to a passenger compartment and to improve start-up emissions of an engine of a vehicle or power system. A pump circulates a fluid through the engine and throughout the system. A radiator and heater core transfer heat from the fluid. A first circuit cools the fluid upon circulation through the radiator after circulation through the engine to cool the engine, and a second circuit heats the passenger compartment and cools the fluid upon circulation through the heater core after circulation through the engine to cool the engine. The reformer, which converts a hydrocarbon or alcohol fuel into a reformate, generates heat. A third circuit, defined between the reformer and the pump and interconnected with the heater core, provides the supplemental heat from the reformer to the passenger compartment through the heater core and also to the engine.

Abstract: A capacity control system for a variable capacity refrigerant compressor includes an internal bleed passage coupling a crankcase chamber of the compressor to a suction port, an electrically-operated two-port control valve that selectively opens and closes a passage between the crankcase chamber and a discharge chamber, and pressure sensors for measuring the compressor discharge pressure and suction pressure. A plunger of the control valve is disposed within the passage coupling the crankcase chamber and the discharge chamber, and a solenoid armature linearly positions the plunger within the passage to open and close the passage. The plunger has an axial bore that forms a continuous passage between the discharge chamber and a cavity in which the discharge pressure sensor is retained so that the sensor is continuously exposed to the discharge pressure regardless of the plunger position.

Abstract: A pneumatically-operated control valve selectively opens and closes a passage between discharge and crankcase chambers of a variable capacity refrigerant compressor for purposes of controlling the compressor capacity, and includes an integral pressure sensor for measuring the compressor discharge pressure. The valve includes a plunger having an axis, a stopper biased against a seat in the passage coupling the discharge and crankcase chambers, an annular bellows and a pressure sensor. A portion of the plunger passes through the annular bellows, and one end of the bellows is attached to the plunger for axially displacing the plunger to unseat the stopper. The stopper and plunger are maintained in engagement, and have axial bores that are aligned to form a passage between the compressor discharge chamber and a cavity in which the pressure sensor is retained.

Abstract: An air conditioning system using a refrigerant to control a temperature of a climate-controlled area. The air conditioning system comprises a refrigerant circuit and a compressor coupled to the refrigerant circuit. The compressor includes a compression mechanism comprising a swash plate and at least one piston engaging the swash plate for compressing the refrigerant. An electric motor has a drive shaft that supports the swash plate at an inclination angle. The swash plate is adjustable between a plurality of inclination angles or stroke positions to adjust a current pressure in a low-side pressure portion of the refrigerant circuit. An electronic control valve adjusts the compression mechanism between the plurality of stroke positions to adjust the current pressure. A controller is programmed to control the electronic control valve until the current pressure is within a predetermined limit of a target pressure.

Abstract: A control method for a motor vehicle HVAC system categorizes potentially conflicting override commands for at least one control parameter in order to assign a priority of control. Override commands are categorized as being related to occupant safety, vehicle safety or occupant comfort. Highest priority is assigned to override commands categorized as being related to occupant safety, second-highest priority is assigned to override commands categorized as being related to vehicle safety, and third-highest priority is assigned to override commands categorized as being related to occupant comfort. An HVAC controller carrying out the control method then regulates the control parameter in accordance with the override command that has been assigned the highest priority.

Abstract: A HVAC system is operable in a fresh air mode and a recirculation mode for use in a vehicle is disclosed. The HVAC system includes a blower and a HVAC module in fluid communication with and downstream of the blower for warming and cooling the air to be circulated through the passenger compartment in both the fresh air mode and the recirculation mode. The HVAC module includes an inlet duct in fluid communication with and upstream of the blower and located above the dashboard for drawing air from the passenger compartment above the dashboard and through the blower and the HVAC module in the recirculation mode. The inlet duct above the dashboard improves air circulation within the passenger compartment that improves the air warm-up rate. The inlet duct above the dashboard also improves the airflow across a windshield to prevent fogging of the windshield.

Abstract: An improved method of electric window heater activation automatically and independently activates front and rear window heaters at a variable level based on the respective potential of fogging, within the ability of the vehicle electrical system to supply the requested current without discharging the storage battery. A defog controller develops front and rear fog factors indicative of the relative potential of fogging, and activates the respective electric heaters as required to drive the respective fog factor to zero. The fog factors are based on an estimate of the cabin air dewpoint temperature, the temperature of the respective window surfaces, and a temperature interval over which the fog factor signals only partial activation of the respective heater. The temperature interval is biased in a direction to provide preventative activation of the heaters at a relatively low level when the electrical power requirement is limited, and the activation level is limited as required to prevent battery discharging.

Abstract: An energy-efficient air conditioning control method regulates the capacity of a variable capacity refrigerant compressor based on the compressor suction and discharge pressures and a measure of the ambient temperature. A target suction pressure is selected based on the ambient temperature and the sensed discharge pressure, and the capacity of the compressor is adjusted as required to attain the target suction pressure. In a first embodiment of the control method, the ambient temperature is used to select a target evaporator outlet air temperature, which is used along with the sensed discharge pressure to select the target suction pressure, while in a second embodiment of the control method, the target suction pressure is selected directly on the basis of the ambient temperature and the sensed discharge pressure.

Abstract: An energy-efficient vehicle air conditioning system includes a variable capacity refrigerant compressor having a capacity control valve with integral refrigerant sensors and control circuitry, and a driver interface panel for selecting the discharge air temperature and inlet air source, and for selecting either a normal control mode or an energy-efficient control mode. When the energy-efficient control mode is selected, control setting indicators prompt the driver to request full-cold discharge air temperature and recirculated cabin air, and the control circuitry initiates a compressor capacity control based on the refrigerant sensor information and a measure of the outside air temperature to produce a suitable discharge air temperature at a reduced power consumption level.

Abstract: An improved method of electric window heater activation automatically and independently activates front and rear window heaters at a variable level based on the respective potential of fogging, within the ability of the vehicle electrical system to supply the requested current without discharging the storage battery. A defog controller develops front and rear fog factors indicative of the relative potential of fogging, and activates the respective electric heaters as required to drive the respective fog factor to zero. The fog factors are based on an estimate of the cabin air dewpoint temperature, the temperature of the respective window surfaces, and a temperature interval over which the fog factor signals only partial activation of the respective heater. The temperature interval is biased in a direction to provide preventative activation of the heaters at a relatively low level when the electrical power requirement is limited, and the activation level is limited as required to prevent battery discharging.

Abstract: A capacity control system for a variable capacity refrigerant compressor includes an internal bleed passage coupling a crankcase chamber of the compressor to a suction port, an electrically-operated two-port control valve that selectively opens and closes a passage between the crankcase chamber and a discharge chamber, and at least one pressure sensor within the control valve that is continuously coupled to the discharge chamber for measuring the compressor discharge pressure. A plunger of the control valve is disposed within the passage coupling the crankcase chamber and the discharge chamber, and a solenoid armature linearly positions the plunger within the passage to open and close the passage. The plunger has an axial bore that forms a continuous passage between the discharge chamber and a cavity in which the pressure sensor is retained so that the sensor is continuously exposed to the discharge pressure regardless of the plunger position.

Abstract: Described is an integrated glass fog sensor unit utilized to provide the necessary data to predict glass fog formation. The unit includes a glass surface temperature sensor, an ambient air temperature sensor, and a relative humidity sensor. The unit is mounted on a thermal barrier tray which serves to thermally isolate the ambient air temperature sensor and the relative humidity sensor from the glass surface. A protective dome having a plurality of apertures covers the tray and sensors. A flex circuit, also acting as a thermal barrier, is utilized to complete the circuit between the sensors and the fog control unit.

Abstract: An improved method and apparatus for diagnosing the condition of an automotive HVAC refrigerant compressor based on information contained within the signal produced by a high-side pressure sensor provided for system control purposes. The output signal of the pressure sensor is divided into its DC and AC components, with the DC component being used for system control purposes, and the AC component being used for diagnosing the condition of the compressor. Pulsations of the AC component (which conventionally are removed by filtering for control purposes) correspond to individual piston stroke cycles. The pulsations indicate compressor operation and are counted for purposes of determining the actual compressor speed. Since existing pressure sensor information is utilized to verify compressor operation and to determine compressor speed, the system cost impact due to the diagnostic evaluation is minimal.