Vehicle auxiliary HVAC system using a coolant loop for cooling a component and vehicle interior

A vehicle includes a heating, ventilation and air conditioning (HVAC) system for heating and cooling a passenger compartment. The HVAC system includes a refrigerant loop and a coolant loop, and an auxiliary heating, ventilation and air conditioning (HVAC) system. The auxiliary HVAC includes an expansion device coupled to the refrigerant loop for controlling a flow of refrigerant to a first heat exchanger, and a second heat exchanger coupled to an auxiliary coolant loop used to regulate a temperature of the component. The auxiliary HVAC further includes a blower for creating an air flow through the first heat exchanger, a first blend door for directing the air flow through the second heat exchanger and/or an outlet, a second blend door for directing the air flow through the outlet and/or a recirculation duct, and a third blend door for controlling the air flow through the recirculation duct.

TECHNICAL FIELD

This document relates generally to vehicle heating/cooling systems, and more specifically to an auxiliary vehicle heating, ventilating, and air conditioning system with an auxiliary coolant loop to cool a component.

BACKGROUND

It is well known to utilize auxiliary heating, ventilating, and air conditioning (HVAC) systems in vehicles. These auxiliary HVAC systems are typically either a blended air system, which is similar to a forced air HVAC system used as a primary HVAC system, or an air conditioning only or heater only system. These auxiliary HVAC systems are typically positioned within a passenger compartment of the vehicle. More specifically, auxiliary HVAC systems are often positioned either in the rear trim assembly, a center console, under a seat, under the vehicle, or otherwise within the compartment.

As with the primary HVAC system, these auxiliary HVAC systems typically have a large footprint or package size considering their positioning within the passenger compartment. In fact, these auxiliary HVAC systems often include some or all of the following: an evaporator core, a heater core, an electric heater, a blower motor and wheel assembly, a blower speed controller, doors, actuators and ducts. Even more, the duct system for the auxiliary HVAC system in larger vehicles, such as sports utility vehicles (SUVs), crossover utility vehicles (CUVs), vans and hybrid vehicles, is typically extensive and extends throughout the passenger compartment in order to distribute conditioned air to varied locations within the compartment (e.g., a second, a third, a fourth, or a fifth row of the vehicle).

While the larger vehicles may provide more cubic feet within the passenger compartment than smaller, more compact, vehicles, the additional space is often utilized for various desired features (e.g., three plus person seating across each row of the passenger compartment). In these scenarios, space within the passenger compartment can become limited. Accommodating this type of seating arrangement or other desired features and a large auxiliary HVAC system, for example, can be difficult and burdensome on vehicle designers. Accordingly, a need exists for an auxiliary HVAC system capable of heating and cooling a passenger compartment, or zones within a passenger compartment, while maintaining a minimal footprint or package size to provide increased flexibility for the vehicle designers.

The auxiliary HVAC system would utilize an auxiliary coolant loop system which is small in size and allows for shorter duct runs for multi-zone conditioning throughout the passenger compartment. Even more, fewer and/or possibly smaller heat exchangers can be utilized limiting the overall package size or footprint of the auxiliary HVAC system. Such an auxiliary HVAC system could also provide spot heating and cooling for lower energy consumption compared to full passenger compartment solutions, and component cooling where components are temperature critical (e.g., a battery pack).

SUMMARY OF THE INVENTION

In accordance with the purposes and benefits described herein, a vehicle is provided. The vehicle may be broadly described as comprising a heating, ventilation and air conditioning (HVAC) system for heating and cooling a passenger compartment, the HVAC system including a refrigerant loop and a coolant loop, and an auxiliary heating, ventilation and air conditioning (HVAC) system including an expansion device coupled to the refrigerant loop for controlling a flow of refrigerant to a first heat exchanger, and a second heat exchanger coupled to an auxiliary coolant loop including a pump for moving a coolant, within the auxiliary coolant loop, near a component in order to regulate a temperature of the component.

The temperature of the coolant within the auxiliary coolant loop is controlled utilizing the flow control valve and the pump.

In one possible embodiment, the auxiliary HVAC system further includes a blower for creating an air flow through the auxiliary HVAC system, and the first heat exchanger is a refrigerant to air heat exchanger and the second heat exchanger is an air to coolant heat exchanger.

In another possible embodiment, the auxiliary HVAC system further includes a blower for creating an air flow through the auxiliary HVAC system and a first blend door, the first blend door positioned downstream of the first heat exchanger for directing the air flow at least partially through an outlet in a passenger compartment cooling mode.

In still another possible embodiment, the auxiliary HVAC system further includes a blower for creating an air flow through the auxiliary HVAC system and a first blend door, the first blend door positioned downstream of the first heat exchanger for directing the air flow at least partially through the second heat exchanger in a component cooling mode.

In yet still another possible embodiment, the auxiliary HVAC system further includes a recirculation duct through which the air flow directed at least partially through the second heat exchanger returns to the blower.

In another possible embodiment, the auxiliary HVAC system further includes a second blend door, the second blend door positioned downstream of the first blend door for further directing the air flow directed at least partially through the second heat exchanger through the recirculation duct.

In yet another, the auxiliary HVAC system further includes a blower for creating an air flow through the auxiliary HVAC system, a first blend door positioned downstream of the first heat exchanger for directing a first portion of the air flow through an outlet and into the passenger compartment and a second portion of the air flow through the second heat exchanger, and a second blend door and a third blend door both positioned downstream of the first blend door for further directing the second portion of the air flow through the outlet, through a recirculation duct back to the blower, or through the outlet and the recirculation duct back to the blower.

In a second possible embodiment, an auxiliary heating, ventilation and air conditioning (HVAC) system for heating and cooling a passenger compartment and cooling a component via an auxiliary coolant loop, includes an expansion device for controlling a flow of refrigerant to a first heat exchanger, a second heat exchanger coupled to the auxiliary coolant loop for regulating a temperature of the component, a blower for creating an air flow through the first heat exchanger, a first blend door downstream of the first heat exchanger for directing the air flow through the second heat exchanger and/or an outlet into the passenger compartment, a second blend door downstream of the first blend door for directing the air flow through the outlet and/or a recirculation duct back to the blower, and a third blend door downstream of the first blend door for controlling the air flow through the recirculation duct.

In one possible embodiment, the component is one or more power storage devices (e.g., a battery), the first heat exchanger is a refrigerant to air heat exchanger, and the second heat exchanger is an air to coolant heat exchanger.

In another possible embodiment, the first blend door directs the air flow through the outlet in a passenger compartment cooling mode. In still another, the first blend door directs the air flow through the second heat exchanger in a component cooling mode.

In still yet another possible embodiment, the second blend door directs the air flow through the third blend door and the recirculation duct in the component cooling mode.

In still another possible embodiment, the first blend door directs a first portion of the air flow through the outlet and a second portion of the air flow through the second heat exchanger in a blended cooling mode.

In another possible embodiment, the second blend door directs the second portion of air flow through the second heat exchanger through the outlet. In still another possible embodiment, the third blend door directs at least a portion of the second portion of air flow through the second heat exchanger through the recirculation duct.

In accordance with the purposes and benefits described herein, a method is provided of cooling a component in a vehicle having an auxiliary heating, ventilation and air conditioning (HVAC) system including an auxiliary coolant loop comprising the steps of: (a) creating an air flow through a first heat exchanger to lower a temperature of the air flow; (b) directing at least a portion of the lowered temperature air flow through a second heat exchanger; (c) pumping coolant through the auxiliary coolant loop to draw heat away from the component; and (d) changing a temperature of the coolant within the auxiliary coolant loop utilizing the second heat exchanger.

In another possible embodiment, the step of changing a temperature of the coolant includes controlling a flow of coolant through the second heat exchanger utilizing a flow valve.

In yet another possible embodiment, substantially all of the lowered temperature air flow is directed through the second heat exchanger in a component cooling mode.

In still another possible embodiment, the method further includes the step of (e) recirculating the lowered temperature air flow directed through the second heat exchanger back to the blower.

In one other possible embodiment, the method further includes the steps of (f) recirculating a first portion of the portion of the lowered temperature air flow directed through the second heat exchanger, and (g) directing a second portion of the portion of the lowered temperature air flow directed through the second heat exchanger through an outlet into a passenger compartment in a blended cooling mode.

In the following description, there are shown and described several embodiments of a vehicle utilizing an auxiliary HVAC system including an auxiliary coolant loop for controlling a temperature of a component. As it should be realized, the methods and systems are capable of other, different embodiments and their several details are capable of modification in various, obvious aspects all without departing from the vehicles and methods as set forth and described in the following claims. Accordingly, the drawings and descriptions should be regarded as illustrative in nature and not as restrictive.

Reference will now be made in detail to the present embodiments of the vehicle utilizing an auxiliary HVAC system including an auxiliary coolant loop for controlling a temperature of a component of the vehicle, examples of which are illustrated in the accompanying drawing figures, wherein like numerals are used to represent like elements.

DETAILED DESCRIPTION

Reference is now made toFIG. 1illustrating a schematic diagram of a typical vehicle heating and cooling system10coupled to an auxiliary heating, ventilation and air conditioning (HVAC) system12for heating and cooling a passenger compartment14. The vehicle cooling and heating system10includes a main heating, ventilation and air conditioning (HVAC) system including a refrigerant loop16and an engine coolant loop17(shown in dashed line) for heating and cooling the passenger compartment14through vents18positioned within an instrument panel20.

In the described embodiment, the refrigerant loop16includes a traditional compressor22driven by a compressor belt24which in turn is driven by a crankshaft26of the vehicle. In operation, the compressor22compresses a fluid, which is a refrigerant in the described embodiment, thereby raising a temperature (T) of the refrigerant. The high temperature, high pressure gas refrigerant leaves the compressor22, as shown by action arrow28, and flows into a condenser30.

Broadly speaking, the condenser30is positioned in the described embodiment at a front section of an engine compartment and cools the refrigerant. Within the condenser, or outside heat exchanger30, the high temperature, high pressure gas refrigerant is condensed due primarily to the effect of outside air, and liquefied. The vehicle may include active grill shutters32which control an amount of air allowed to pass over the outside heat exchanger30. As shown, a fan34is also utilized in the described embodiment to create and regulate the flow of air through the active grill shutters32, over the outside heat exchanger30and an engine radiator36.

The high pressure, liquefied refrigerant is then sent to a first (cooling) expansion device38and a second (cooling) expansion device40, as shown by action arrows42and44respectively. In the first (cooling) expansion device38, the liquid refrigerant is expanded to become a low-temperature, low-pressure liquid and vapor mixture refrigerant. This low-temperature, low-pressure liquid and vapor mixture refrigerant is supplied to a refrigerant to air heat exchanger, or evaporator, designated numeral46. Regulation of the flow of refrigerant, or throttling, is used to control the temperature of the refrigerant within the evaporator46.

In a cooling mode, warm, moist air flowing across the evaporator46transfers its heat to the cooler refrigerant within the evaporator. The byproducts are a lowered temperature air and condensation from the air. The condensation is routed from the evaporator46to an exterior of the vehicle. A blower48blows air across the evaporator46and through the one or more vents18to the passenger compartment14. This process results in the passenger compartment14having a cooler, drier air therein.

As indicated above, the system10further includes an engine coolant loop17including a coolant pump (not shown) that pumps coolant or antifreeze through the engine56. The coolant draws heat from the engine56and routes a portion of the heated coolant through a coolant to air heat exchanger58positioned within the vehicle HVAC case60.

In a heating mode, a blend door (not shown) is used to regulate the flow of air created by the blower48allowing air to travel through, or partially through, the coolant to air heat exchanger58. The heated coolant flowing through the coolant to air heat exchanger58transfers its heat to the air flowing across the coolant to air heat exchanger. The byproducts are a raised temperature air entering the passenger compartment14through vents18and a lowered temperature coolant. The now lowered temperature engine coolant flowing from the coolant to air heat exchanger58, as shown by action arrow62, moves back through the engine56where the coolant is reheated and cycled through the system10as described above.

The auxiliary HVAC system12provides auxiliary cooling of at least portions of the passenger compartment14through ducting68and one or more vents70positioned within the passenger compartment. In the second (cooling) expansion device40, the liquid refrigerant is similarly expanded to become a low-temperature, low-pressure liquid and vapor mixture refrigerant. This low-temperature, low-pressure liquid and vapor mixture refrigerant is supplied to a refrigerant to air heat exchanger, or evaporator, designated numeral72. Regulation of the flow of refrigerant, or throttling, is used to control the temperature of the refrigerant within the evaporator72. In the described embodiment shown inFIG. 1, the evaporator72is positioned within an auxiliary HVAC case130located in the passenger compartment14. In alternate embodiments, however, the auxiliary HVAC case and/or evaporator72may be located under the vehicle, or within an engine or other compartment.

In a cooling mode, warm, moist air flowing across the evaporator72transfers its heat to the cooler refrigerant within the evaporator. The byproducts are a lowered temperature air and condensation from the air. The condensation is routed from the evaporator72to an exterior of the vehicle. A blower64creates the flow of air across the evaporator72and through the one or more vents70to the passenger compartment14. This process results in the passenger compartment14having a cooler, drier air therein.

The low pressure refrigerant exits the refrigerant to air heat exchanger72, as shown by action arrows74, and recombines with low pressure refrigerant exiting evaporator46, as shown by action arrow76, at point80. The combined low pressure refrigerant reenters the compressor22, as shown by action arrow82, where the refrigerant is again compressed and cycled through the system10.

The auxiliary HVAC system12further includes an auxiliary coolant loop66for regulating a temperature of a component84(e.g., a battery, electronics, or food/drinks) within a compartment86. The auxiliary coolant loop66includes a coolant pump88that pumps coolant or antifreeze through the compartment86as shown by action arrow90. The coolant in the auxiliary coolant loop66absorbs heat from the component84as the coolant passes through the compartment86before being pumped into an air to coolant heat exchanger92as shown by action arrow94.

The pump88and a flow control valve96work together to control the temperature of the coolant within the auxiliary coolant loop66. In the cooling mode described above wherein maximum cooling of the passenger compartment14is desired, the flow control valve96and pump88limit, if not stop, movement of the coolant within the auxiliary coolant loop66. Alternatively, in a maximum component cooling mode, the flow control valve96and pump88allow the coolant to flow past the component84within the compartment86.

As generally shown inFIG. 2, the auxiliary HVAC system12includes the expansion valve40, the blower64, the refrigerant to air heat exchanger, or evaporator,72, the air to coolant heat exchanger, or heater core,92, an outlet98connected to the ducting68, and a recirculation duct106and blend door104. Even more, as shown inFIG. 3, the auxiliary HVAC system12includes first, second, and third blend doors100,102, and104, respectively. The blend doors are used to control and/or regulate the flow of air created by the blower64.

In the maximum passenger compartment cooling mode shown inFIG. 3, the first blend door100and the second blend door102are moved to fully closed positions. In these positions, the first and second blend doors100,102prevent the blown air from travelling through the air to coolant heat exchanger92and a recirculation duct106back to the blower64. In this mode, the coolant pump88is turned off and coolant is not circulated through the auxiliary coolant loop66and component compartment86, and the blown air flows directly into the passenger compartment14, as shown by action arrow110, via ducting68.

In a maximum component cooling mode shown inFIG. 4, the first blend door100is moved to a fully open position generally preventing the blown air from entering the passenger compartment14via outlet98. In this mode, the first blend door100directs the blown air through the coolant to air heat exchanger92as shown by action arrows112. The portion of the heated coolant flowing through the coolant to air heat exchanger92transfers its heat to the air flowing across the coolant to air heat exchanger. The byproducts are a raised temperature air and a lowered temperature coolant within the auxiliary coolant loop66.

The second blend door102is similarly moved to a fully closed position in the maximum component cooling mode thereby generally preventing the raised temperature air from entering the passenger compartment14via outlet98. Instead, the third blend door104is opened allowing the heated air flowing through the coolant to air heat exchanger92into the recirculation duct106as shown by action arrows114. The heated air flows through the recirculation duct106back to the blower64where it is recirculated through the evaporator72and cooled prior to entering the coolant to air heat exchanger92. In other words, in the maximum component cooling mode, the first and second blend doors100and102are positioned to prevent air flow from entering the passenger compartment14and the third blend door104is positioned to direct the heated air into the recirculation duct106and back to the blower64.

In one blended mode shown inFIG. 5, the third blend door104is moved to a fully closed position generally preventing air from entering the recirculation duct106. At the same time, the first and second blend doors100and102are used to regulate the flow of air created by the blower64. As shown, both the first and second doors are positioned to allow the flow of air to travel partially through the coolant to air heat exchanger92as shown by action arrows116and partially bypass the coolant to air heat exchanger92into the passenger compartment14as shown by action arrows118.

The portion of the heated coolant flowing through the coolant to air heat exchanger92transfers its heat to the air flowing across the coolant to air heat exchanger. The byproducts are a raised temperature air entering the passenger compartment14via outlet98, as shown by action arrow120, and a lowered temperature coolant. Before entering the passenger compartment14, the raised temperature air is blended with the portion of the air flow allowed to bypass the coolant to air heat exchanger92into the passenger compartment14as shown by action arrows118. Positioning of the first and second blend doors102and104is one method of controlling the temperature of the blended air entering the passenger compartment14. In alternate modes of operation, the third blend door104may be opened or partially opened allowing at least a portion of the raised temperature air to enter the recirculation duct106as described above.

In the heating mode, with the compressor off, no refrigerant is moving through the second (cooling) expansion device40or the refrigerant to air heat exchanger72. In this mode, the pump88may likewise be turned off such that no coolant is moving within the auxiliary coolant loop66. Alternatively, the pump88may continue to operate pumping coolant through the auxiliary coolant loop66such that the coolant is warmed by a transfer of heat within the compartment86. The warmed coolant then moves to the coolant to air heat exchanger92where the warmed coolant transfers heat to the air flowing across the coolant to air heat exchanger created by the blower64. The warmed air flows through outlet98and to one or more vents70positioned within the passenger compartment14through ducting68. This process results in at least a portion of the passenger compartment14having a warmer air therein and provides cooling to the component84within the compartment86.

In other alternate embodiments, a valve may be added to the auxiliary coolant loop66for selectively directing the moving coolant through one or more additional compartments for housing one or more additional components in order to regulate a temperature of the components. The valve would operate to allow the coolant to move normally within the auxiliary coolant loop or to be diverted through the one or more additional compartments when component cooling is desired. Of course, one or more valves may be added to the auxiliary coolant loop if multiple compartments are utilized within the vehicle.

In summary, numerous benefits result from the vehicle utilizing an auxiliary HVAC system for controlling a temperature within a passenger compartment and cooling a component using an auxiliary coolant loop as illustrated in this document. The auxiliary coolant loop maintains the component within an optimum temperature range while waste heat from the component is utilized to reheat the auxiliary discharge air. The use of an auxiliary HVAC system provides increased flexibility for vehicle designers including allowing shorter duct runs for multi-zone air conditioning throughout the passenger compartment and the utilization of fewer and/or possibly smaller heat exchangers. Even more, the system allows for spot heating and cooling resulting in lower energy consumption compared to full passenger compartment solutions, and component cooling without significantly effecting the temperature of the passenger compartment, if at all.

The foregoing has been presented for purposes of illustration and description. It is not intended to be exhaustive or to limit the embodiments to the precise form disclosed. For example, the expansion devices in the described embodiment could be electronic expansion devices. Obvious modifications and variations are possible in light of the above teachings. All such modifications and variations are within the scope of the appended claims when interpreted in accordance with the breadth to which they are fairly, legally and equitably entitled.