Patent Application
20140060102
The disclosure relates to a vehicular heat pump system for use in mild ambient temperatures.
In conventional heating, ventilating, and air conditioning (HVAC) systems, two separate fluid circuits are present: a refrigerant fluid circuit for cooling the cabin and a coolant fluid circuit for heating the cabin. The cooling circuit circulates a refrigerant which may be a compound such as R-134a or the like. The heating circuit circulates a fluid which may generally be a mixture of ethylene glycol and water. Such HVAC systems may include reversible refrigerant heat pump systems, in which the refrigerant flow is controlled by refrigerant valves, thus, permitting the heat pump system to operate in both cabin heating mode and cabin cooling mode, by reversing the function of the two heat exchangers.
In cabin cooling mode, refrigerant flows from the compressor through an outside heat exchanger acting as a condenser, into an expansion valve, and through an inside heat exchanger acting as an evaporator. Heat is extracted from the air blown across the inside heat exchanger (evaporator), thereby providing cooled air to the passenger compartment.
In cabin heating mode, the refrigerant heat exchanger located outside the passenger compartment (outside heat exchanger) acts as an evaporator. The refrigerant heat exchanger inside the passenger compartment (inside heat exchanger) acts as a condenser. The refrigerant flows from the compressor through the inside heat exchanger acting as a condenser, into a receiver and orifice tube or other type of expansion device, and through the outside heat exchanger acting as an evaporator. Heat from the refrigerant is absorbed by the air flowing across the inside heat exchanger, which is blown into the passenger compartment to provide heat.
A vehicular heat pump system for controlling the temperature of the passenger compartment and vehicle battery, for use in mild ambient temperatures, is provided. The heat pump system may include two operating modes: a cooling mode and a heating mode, which, in operation, may circulate a refrigerant. The refrigerant is generally directed along a heating circuit in heating mode and a cooling circuit in cooling mode. The refrigerant may be directed along one of the respective heating circuit or cooling circuit and through a plurality of components to cool or warm the passenger compartment and to cool the vehicle battery.
The vehicular heat pump system may include a compressor, an AC condenser, a heat pump condenser, a cabin evaporator, a rechargeable energy storage system (RESS) chiller acting as heat pump evaporator, a receiver dryer, a plurality of expansion devices, and a plurality of flow control valves.
The vehicular heat pump system may operate in two operating modes, namely heating mode and cooling mode, either independently or simultaneously. During heating mode, the system employs a heat pump condenser, inside the HVAC module or within the vehicle underhood, and the RESS chiller as the heat pump evaporator. Additionally, the heating circuit may include a cabin evaporator, which may be configured to cool and dehumidify air transmitted to the passenger compartment. In cooling mode, the system utilizes an independent AC condenser outside the HVAC module, and a cabin evaporator.
It is, therefore, not necessary to require the reversal of refrigerant flow when changing operating modes. Absent the requirement to reverse the system, the position of the low-pressure side of the system, defined between one of the plurality of expansion devices and the compressor, remains constant in all operating modes reducing or eliminating the need to de-ice an outside heat exchanger in heating mode, and allowing uninterrupted heating of the passenger compartment.
The above features and advantages, and other features and advantages, of the present invention are readily apparent from the following detailed description of some of the best modes and other embodiments for carrying out the invention, as defined in the appended claims, when taken in connection with the accompanying drawings.
The following description and figures refer to example embodiments and are merely illustrative in nature and not intended to limit the invention, its application, or uses. Throughout the figures, some components are illustrated with standardized or basic symbols. These symbols are representative and illustrative only, and are in no way limiting to any specific configuration shown, to combinations between the different configurations shown, or to the claims. All descriptions of componentry are open-ended and any examples of components are non-exhaustive.
Referring to the figures, wherein like reference numbers correspond to like or similar components throughout the several views, a vehicular heat pump system 100, 200 for controlling the temperature of a vehicle passenger compartment 122 and vehicle battery 115, for use in cool and mild ambient temperatures is provided and shown in a variety of configurations and operating modes, in
The heat pump system 100, may operate in two modes: a cooling mode, as shown in
The heating circuit 125, shown generally in
The heating circuit 125 has a distinct high-pressure side and low-pressure side. The high-pressure side, wherein the refrigerant is in a condensed high pressure state, is defined between a compressor outlet 127 and each of the respective expansion devices 107, 108. The low-pressure side of the system, wherein the refrigerant in an expanded, low pressure state, is defined between each of the respective expansion devices 107, 108 and the compressor inlet 126.
The compressor 102 may be driven by an electric motor (not shown), which may be of the single or variable speed variety. The compressor 102 may also be a pump driven by a belt connected to the engine crankshaft (not shown). The compressor 102 may include a compressor inlet 126 and a compressor outlet 127. The compressor 102 may be configured to receive refrigerant gas on the low-pressure side of the system at the compressor inlet 126 and may pressurize the refrigerant gas into a high-pressure state. The compressor 102 may be further configured to expel compressed refrigerant gas to the compressor outlet 127, exiting on the high-pressure side of the system.
The at least one low-side refrigerant pressure sensor 116 may be positioned on the low-pressure side of the compressor 102 proximate the compressor inlet 126. The at least one high-side refrigerant pressure sensor 117 may be positioned on the high-pressure side of the compressor 102 proximate the compressor outlet 127.
The heating circuit 125 may additionally include a first flow control valve 114 that may be fully open when the heat pump system 100 is operating in heating mode. The first flow control valve 114 may be fully open in heating mode and may be configured to direct and selectively distribute refrigerant to the heat pump condenser 111a. The third flow control valve 104 may be fully closed in heating mode. The second flow control valve 106 may be fully open, in heating mode, if passenger compartment 122 dehumidification is needed; the second flow control valve 106 may be fully closed, in heating mode, if passenger compartment 122 dehumidification is not needed.
The heat pump condenser may be a refrigerant-to-air heat exchanger 111a located within the HVAC module 121, as shown in
The receiver dryer 105 may include a receiver dryer inlet 134 and a receiver dryer outlet 135. The receiver dryer 105 may further include a plurality of desiccants (not shown) to attract and remove moisture from the system 100. The receiver dryer 105 may receive the high-pressure refrigerant liquid at the receiver dryer inlet 134 and expel the high pressure refrigerant liquid from the receiver dryer outlet 135.
The first expansion device 108 may allow the high pressure liquid refrigerant to expand, reducing the pressure in the system 100. The first expansion device 108 may direct and selectively distribute refrigerant to the RESS chiller 110, at a significantly reduced pressure. The first expansion device 108 may be a thermostatic or thermal expansion valve, and may be configured to hold a constant evaporator superheat state as the refrigerant enters RESS chiller 110, which acts as a heat pump evaporator. The thermostatic or thermal expansion valve may be a conventional, mechanically driven, thermal expansion valve, with which no electronic devices are associated, as shown in
The RESS chiller 110 may be located outside the HVAC module 121. The RESS chiller 110 may function as a heat pump evaporator that may include coils (not shown) or the like to dissipate heat from the battery 115 to the cooled refrigerant. The RESS chiller 110 may direct refrigerant over the low-side pressure sensor 116 and back to the compressor 102.
If dehumidification of the passenger compartment 122 is needed, the heating circuit 125 may also circulate refrigerant along flow path 150, as shown in
The second expansion device 107 may control and selectively distribute refrigerant to the cabin evaporator 113, at a significantly reduced pressure. The second expansion device 107 may be a thermostatic or thermal expansion valve, and is configured to hold a constant evaporator superheat state as the refrigerant enters the cabin evaporator 113. The thermostatic or thermal expansion valve may be a conventional, mechanically driven, thermal expansion valve, with which no electronic devices are associated, as shown in
The cabin evaporator 113 may be located within the HVAC module 121. The cabin evaporator 113 may include coils (not shown). The cabin evaporator 113 may be configured to cool and dehumidify the air flowing across the coils (not shown) and into the passenger compartment 122. The cabin evaporator 113 may further include a fan (not shown) to direct air over the coils impregnated with refrigerant, and facilitate the direction of the air into the passenger compartment 122. The cabin evaporator 113 may be further configured to direct refrigerant over the low-side pressure sensor 116 and back to the compressor 102.
The cooling circuit 124, shown generally in
The cooling circuit 124 has a distinct high pressure side and low pressure side. The high pressure side, wherein the refrigerant is in a condensed high pressure state, is defined between a compressor outlet 127 and each of the respective expansion devices 107, 108. The low pressure side of the system, wherein the refrigerant in an expanded low pressure state, is defined between each of the respective expansion devices 107, 108 and the compressor inlet 126.
The compressor 102 may be driven by an electric motor (not shown), which may be of the single or variable speed variety. The compressor 102 may also be a pump driven by a belt connected to the engine crankshaft (not shown). The compressor 102 may include a compressor inlet 126 and a compressor outlet 127. The compressor 102 may receive refrigerant gas on the low pressure side of the system at the compressor inlet 126 and may pressurize the refrigerant gas into a high pressure state. The compressor 102 may direct compressed refrigerant gas to the compressor outlet 127, exiting on the high pressure side of the system 100.
The at least one low-side refrigerant pressure sensor 116 may be positioned on the low-pressure side of the compressor 102 proximate the compressor inlet 126. The at least one high-side refrigerant pressure sensor 117 may be positioned on the high-pressure side of the compressor 102 proximate the compressor outlet 127.
In cooling mode, the first flow control valve 114 may be fully closed. Each of the respective second flow control valve 106 and third flow control valve 104 may be fully open, in cooling mode and may be further configured to receive and expel refrigerant.
The AC condenser 103 may be located outside the HVAC module 121. The AC condenser 103 may include an AC condenser inlet 130 and an AC condenser outlet 131. The AC condenser 103 may receive pressurized refrigerant gas at the condenser inlet 130, and may cool and condense the pressurized refrigerant gas as it flows through the AC condenser 103, to the extent that the pressurized refrigerant gas is cooled and condensed to a point at which it is reclaimed into a liquid state. The AC condenser outlet 131 may be configured to expel cooled liquid refrigerant.
The receiver dryer 105 may include a receiver dryer inlet 134 and a receiver dryer outlet 135. The receiver dryer 105 may further include a plurality of desiccants (not shown) to attract and remove moisture from the system 100. The receiver dryer 105 may receive the high-pressure refrigerant liquid at the receiver dryer inlet 134 and expel the high pressure refrigerant liquid from the receiver dryer outlet 135 to one of the first expansion device 108 and the second expansion device 107.
The first and second expansion devices 108, 107 may allow the high pressure liquid refrigerant to expand, reducing the pressure of the refrigerant as it exits the first and second expansion devices 108, 107. The first and second expansion devices 108, 107 may be further configured to control and selectively distribute refrigerant to each of the respective RESS chiller 110 functioning as a heat pump evaporator and cabin evaporator 113, at a significantly reduced pressure. The first and second expansion devices 108, 107 may be thermostatic or thermal expansion valves, and may be configured to hold a constant evaporator superheat state as the refrigerant enters one of the RESS chiller 110, which acts as a heat pump evaporator and the cabin evaporator 113. Each of the respective first expansion device 108 and second expansion device 107 may be either electronic or mechanical in any of the configurations shown in
The RESS chiller 110 may include coils (not shown) or the like to dissipate heat from the battery 115 to the cooled refrigerant. The RESS chiller 110 may direct refrigerant over the low-side pressure sensor 116 and back to the compressor 102.
The cabin evaporator 113 may be located within the HVAC module 121. The cabin evaporator 113 may include coils (not shown), which may function to allow the refrigerant flow across the coils (not shown). The cabin evaporator 113 may be configured to cool and dehumidify the air flowing across the coils (not shown) and into the passenger compartment 122. The cabin evaporator 113 may further include a fan (not shown) to direct air over the coils impregnated with refrigerant, and facilitate the direction of the air into the passenger compartment 122. The cabin evaporator 113 may be configured to direct refrigerant over the low-side pressure sensor 116 and back to the compressor 102.
As shown in
Illustrative examples of the vehicular heat pump system 100, 200 are shown in
The high pressure refrigerant gas may be expelled from the compressor outlet 127 and directed across a high-side pressure sensor 117, to the first flow control valve 114. The first flow control valve 114 may be fully open in heating mode, and may be configured to direct and selectively distribute the high pressure refrigerant gas to the heat pump condenser 111a.
The heat pump condenser 111a, may be a refrigerant-to-air heat exchanger and may be housed within the HVAC module 121. The heat pump condenser 111a may be configured to receive the high-pressure refrigerant gas from the first flow control valve 114 at the heat pump condenser inlet 128. The heat pump condenser 111a may, additionally, be configured to cool and condense the pressurized refrigerant gas as it flows through the heat pump condenser 111a, to the extent that the refrigerant reclaims liquid form. The heat extracted from the refrigerant may be exchanged to the air flowing across the heat pump condenser 111a. The heated air may be directed to the passenger compartment 122. The cooled liquid refrigerant may be expelled from the heat pump condenser outlet 129 and directed to the receiver dryer 105.
The receiver dryer 105 may be configured to receive the liquid refrigerant at the receiver dryer inlet 134 from the heat pump condenser 111a. The receiver dryer 105 may be further configured to remove moisture from the system 100 through the use of a plurality of desiccants (not shown), which may attract and remove additional moisture from the refrigerant being directed to one of the cabin evaporator 113 and the RESS chiller 110 acting as a heat pump evaporator. After the excess moisture is extracted from the system 100, the refrigerant liquid may be expelled from the receiver dryer outlet 135 and directed to at least one of the first expansion device 108 or second expansion device 107.
If cabin dehumidification is not needed, the second flow control valve 106 may be fully closed and all refrigerant expelled from the receiver dryer 105 may be directed to the first expansion device 108. If cabin dehumidification is needed, the second flow control valve 106 may be fully open and the refrigerant expelled from the receiver dryer 105 may be directed and selectively distributed to one of the first expansion device 108 and the second expansion device 107.
High pressure, liquid refrigerant may be directed from the receiver dryer 105 to the first expansion device 108. The first expansion device 108 may be configured to receive refrigerant and further configured to allow the liquid refrigerant to depressurize and expand. The first expansion device 108 may be further configured to direct and selectively distribute refrigerant to the RESS chiller 110, which may act as a heat pump evaporator.
The RESS chiller 110 acting as a heat pump evaporator may be configured to receive the cooled liquid refrigerant from the first expansion device 108. The RESS chiller 110 may be further configured to dissipate excess heat from the battery 115 to the refrigerant, and expel the refrigerant over the at least one low-side pressure sensor 116 and back to compressor 102.
High pressure, liquid refrigerant may also be directed from the receiver dryer 105 to the second expansion device 107. Refrigerant directed to the second expansion device 107 may flow along flow path 150 and may first pass through the second flow control valve 106, which may be fully open, when cabin dehumidification is needed. The second flow control valve 106 may be configured to direct and selectively distribute refrigerant to the second expansion device 107. The second expansion device 107 may be configured to receive the liquid refrigerant and allow the liquid refrigerant to depressurize and expand. The second expansion device 107 may be further configured to direct and selectively distribute refrigerant to the cabin evaporator 113.
The cabin evaporator 113 may be configured to receive the cooled liquid refrigerant from the second expansion device 107. The cabin evaporator 113 may be further configured to cool and dehumidify the air flowing across the cabin evaporator 113 and into the passenger compartment 122. The cabin evaporator 113 may be further configured to expel the refrigerant over the low-side pressure sensor 116 and back to the compressor 102.
In the second configuration, shown in
The high-pressure refrigerant gas may be directed from the compressor outlet 127 across a high-side pressure sensor 117 and directed to an AC condenser 103. The AC condenser 103 may be configured to receive the high-pressure refrigerant gas at an AC condenser inlet 130. The AC condenser 103 may additionally be configured to cool and condense the high-pressure refrigerant gas, to the extent that the refrigerant reclaims liquid form. The cooled liquid refrigerant may be expelled from the AC condenser outlet 131 and directed to the third flow control valve 104. The third flow control valve 104 may be configured to direct and selectively distribute the high-pressure refrigerant gas to the receiver dryer 105.
The receiver dryer 105 may be configured to receive the liquid refrigerant at the receiver dryer inlet 134. The receiver dryer 105 may be further configured to remove moisture from the system through the use of a plurality of desiccants (not shown), which may attract and remove moisture prior to the refrigerant being directed to one of the cabin evaporator 113 and RESS chiller 110. After the excess moisture is extracted from the system, the refrigerant liquid may be expelled from the receiver dryer outlet 135 and directed and selectively distributed to one of the second flow control valve 106 and the first expansion device 108. The selective direction by the at least one control module 123 may be based on the necessary balance between the cooling of the passenger compartment 122 and the cooling of the battery 115.
If cooling is desired in the passenger compartment 122 only, all refrigerant will be directed to the second flow control valve 106, which will be fully open, and on to second expansion device 107. If cooling is desired for the battery 115 only, all refrigerant will be directed to the first expansion device 108, as the second flow control valve 106 will be fully closed. If both the passenger compartment 122 and the battery 115 require cooling, the refrigerant will be directed and selectively distributed to each of the respective first expansion device 108 and the second expansion device 107.
High-pressure, liquid refrigerant directed to the second expansion device 107 may first pass through the second flow control valve 106, which may be fully open in cooling mode. The second flow control valve 106 may be configured to direct, selectively distribute, and meter refrigerant to the second expansion device 107. The second expansion device 107 may be configured to receive the liquid refrigerant and allow the liquid refrigerant to depressurize and expand. The second expansion device 107 may direct and selectively distribute refrigerant to the cabin evaporator 113.
The cabin evaporator 113 may be configured to receive the cooled liquid refrigerant from the second expansion device 107. The cabin evaporator 113 may be further configured to cool and dehumidify the air flowing across the cabin evaporator 113 and into the passenger compartment 122. The cabin evaporator 113 may be further configured to expel and direct the refrigerant over the low-side pressure sensor 116 and back to the compressor 102.
If battery 115 cooling is needed in addition to passenger compartment 122 cooling, high-pressure liquid refrigerant may also be directed from the receiver dryer 105 to the first expansion device 108 in cooling mode. The first expansion device 108 may be configured to receive the liquid refrigerant from the receiver dryer 105 and allow the liquid refrigerant to depressurize and expand. The first expansion device 108 may be further configured to direct and selectively distribute refrigerant to the RESS chiller 110.
The RESS chiller 110 may act as a heat pump evaporator. The RESS chiller 110 may be configured to receive the cooled liquid refrigerant from the first expansion device 108. The RESS chiller 110 may be further configured to dissipate excess heat from the battery 115 to the refrigerant, and expel and direct the refrigerant over the low-side pressure sensor 116 and back to the compressor 102.
In the fourth configuration of the first embodiment, shown in
The heating circuit 125 of the second embodiment may contain substantially the same structure as described with respect to the first embodiment described above. However, the heat pump condenser 111c may be a refrigerant-to-coolant heat exchanger rather than a refrigerant-to-air heat exchanger 111a. Further, in the third example embodiment, the refrigerant-to-coolant heat pump condenser 111c may be located in the vehicle underhood 152, rather than within the HVAC module 121.
The refrigerant-to-coolant heat pump condenser 111c may include a refrigerant cavity 140 and a coolant cavity 137. The refrigerant cavity 140 may include a refrigerant inlet 146 and a refrigerant outlet 148. The coolant cavity 137 may include a coolant inlet 138 and a coolant outlet 139.
The refrigerant-to-coolant heat pump condenser 111c may be configured to receive pressurized refrigerant gas at the refrigerant inlet 146, and may extract heat from the pressurized gas as it flows through the refrigerant cavity 140 to the extent that the pressurized refrigerant gas is cooled and condensed to a point at which it is reclaimed into a liquid state. The heat extracted from the refrigerant as it flows through the refrigerant cavity 140 may be transferred to the coolant flowing through the coolant cavity 137.
The warmed coolant flowing through the coolant cavity 137 may be expelled from the coolant outlet 139 and directed through a coolant heater core 112. The coolant heater core 112 may be housed in the HVAC module 121. Heat may then be transferred from the coolant flowing through the coolant heater core 112 to the air flowing across the coolant heater core 112. The heated air may be directed across the coolant heater core 112 to the passenger compartment 122.
In vehicles that are electric only propulsion vehicles, the vehicular heat pump system 200 may further include: an electric coolant pump 144. In such systems, coolant may be expelled from the coolant heater core 112 and directed to the electric coolant pump 144. The electric coolant pump 144 may be configured to receive coolant from the coolant heater core 112 and expel coolant to the coolant cavity 137. The coolant cavity 137 may be configured to receive coolant from the electric coolant pump 144 at the coolant cavity inlet 138.
In advanced propulsion vehicles, the vehicular heat pump system 200 may further include an electric coolant pump 144; a heating source 143, such as an internal combustion engine, a fuel cell stack, a fuel operated heater, a thermal storage device or the like; and a coolant valve 142. In such systems, coolant may be expelled from the coolant heater core 112 and directed to the coolant valve 142. The coolant valve 142 may be a three-way, two-position valve and may be configured to direct coolant flow from the heater core 112 to the coolant pump 144, when the heating source 143 is too cold to operate. When the heating source 143 is sufficiently warmed, the coolant valve 142 may be further configured to direct coolant flow from the coolant heater core 112 to the heating source 143, which may expel coolant to the coolant pump 144.
The cooled, liquid refrigerant may be expelled from the heat pump condenser outlet 148 and directed to the receiver dryer 105. The receiver dryer 105 may be configured to receive the liquid refrigerant at the receiver dryer inlet 134. The receiver dryer 105 may be further configured to remove moisture from the system through the use of a plurality of desiccants (not shown), which may attract and remove additional moisture from the refrigerant. After the excess moisture is extracted from the system 100, the refrigerant liquid may be expelled from the receiver dryer outlet 135 and directed to at least one of the respective first expansion device 108 or the second expansion device 107.
If cabin dehumidification is not needed, all refrigerant expelled from the receiver dryer 105 may be directed to the first expansion device 108, as the second flow control valve 106 will be fully closed. If cabin dehumidification is needed, the refrigerant expelled from the receiver dryer 105 may be directed and selectively distributed to one of the first expansion device 108 and the second expansion device 107, through the fully open second control valve 106.
High pressure, liquid refrigerant directed to the second expansion device 107, may flow along flow path 150 and may first pass through the second flow control valve 106. The second flow control valve 106, may be fully open in heating mode if passenger compartment 122 dehumidification is needed. The second flow control valve 106 may be configured to direct and selectively distribute refrigerant to the second expansion device 107. The second expansion device 107 may be configured to receive the liquid refrigerant and allow the liquid refrigerant to depressurize and expand. The second expansion device 107 may be further configured to direct and selectively distribute refrigerant to the cabin evaporator 113.
The cabin evaporator 113 may be configured to receive the cooled, liquid refrigerant from the second expansion device 107. The cabin evaporator 113 may be further configured to cool and dehumidify the air flowing across the evaporator 113 and into the passenger compartment 122. The cabin evaporator 113 may be further configured to expel and direct refrigerant over the low-side pressure sensor 116 and back to the compressor 102.
Refrigerant may also be directed from the receiver dryer 105 to the first expansion device 108. The first expansion device 108 may be configured to receive and allow the liquid refrigerant to depressurize and expand. The first expansion device may be further configured to direct and selectively distribute refrigerant to the RESS chiller 110.
The RESS chiller 110 may act as a heat pump evaporator and may be configured to receive the cooled, liquid refrigerant from the first expansion device 108. The RESS chiller 110 may be further configured to dissipate excess heat from the battery 115 to the refrigerant, and expel and direct the refrigerant over the low-side pressure sensor 116 and back to the compressor 102.
The mild ambient heat pump system 100 maintains an independent heating circuit 125 and an independent cooling circuit 124. Therefore, the system 100 does not require a reversing upon a change to the operating mode. Each of the heat exchangers always function as an evaporator 110, 113 or always functions as a condenser 103, 111a, 111c, rather than as conventional heat exchangers, which switch between evaporator function and condenser function upon a change in operating mode. Accordingly, the position of the low-pressure side of the system remains constant in all operating modes. The low-pressure side of the system is always defined between each of the respective expansion devices 107, 108 and the compressor inlet 126. Additionally, the low-pressure side of the heat pump system is not directly cooled with ambient air. Such a configuration of the vehicular heat pump system 100, 200 allows for passenger compartment 122 heating in EV mode in mild and cold ambient temperatures without interruption, as the de-icing of the RESS chiller 110 during heating mode is not necessary. Such a system 100, 200 also preserves underhood 152 packing space which can be scarce in hybrid or electric vehicle models.
The detailed description and the drawings or figures are supportive and descriptive of the invention, but the scope of the invention is defined solely by the claims. While some of the best modes and other embodiments for carrying out the claimed invention have been described in detail, various alternative designs and embodiments exist for practicing the invention defined in the appended claims.
