WO2015195633A1

WO2015195633A1 - Coolant isolation system

Info

Publication number: WO2015195633A1
Application number: PCT/US2015/035984
Authority: WO
Inventors: Long K. Hwang; Michael J. Marthaler; Richard E. Kleine; Adam E. THOMPSON
Original assignee: Cummins Inc.
Priority date: 2014-06-16
Filing date: 2015-06-16
Publication date: 2015-12-23

Abstract

A coolant isolation system for isolating the coolant used within an engine cooling circuit and a vehicle HVAC circuit is provided comprising a first fluid circuit coupled to an engine of the vehicle, the first fluid circuit providing a flow path through the engine for a first fluid; a second fluid circuit in a passenger compartment of the vehicle, the second fluid circuit providing a flow path for a second fluid; and a fluid isolator coupled to the first fluid circuit and the second fluid circuit, the fluid isolator structured to transfer heat from the first fluid to the second fluid, wherein the first and second fluids flow through the fluid isolator but do not contact one another.

Description

PATENT APPLICATION of LONG K. HWANG MICHAEL J. MARTHALER

RICHARD E. KLEINE and ADAM E. THOMPSON for COOLANT ISOLATION SYSTEM

Attorney Docket No.: CI-14-0198-02-WO-E Cummins Reference No.: 14-0198-EBU COOLANT ISOLATION SYSTEM CROSS-REFERENCE TO RELATED APPLICATION

[0001] This application claims priority to U.S. Provisional Application Serial No. 62/012,498, filed on June 16, 2014, the disclosure of which is expressly incorporated herein by reference. FIELD OF THE DISCLOSURE

[0002] The present disclosure generally relates to engine cooling and vehicle climate control systems, and more particularly to a coolant isolation system which isolates an engine cooling system from a vehicle’s Heating Ventilation and Air Conditioning (“HVAC”) system. BACKGROUND OF THE DISCLOSURE

[0003] In general, many vehicles, such as transit and passenger buses, typically include HVAC systems as well as engine cooling systems to facilitate heating/cooling of passenger compartments and cooling of critical engine hardware components. Thermal management systems, or cooling systems, are generally standard within conventional internal combustion engine vehicles. Conventional systems typically employ a single coolant circuit that circulates coolant within both the engine cooling system and the vehicle HVAC system. In such systems, engine component failures occur due to loss of coolant or air ingestion from a vehicle’s HVAC system. Such failures increase the costs of warranty repairs by manufacturers in the transit vehicle market. Additionally, such failures often result in costly Exhaust Gas Recirculation (EGR) cooler failures.

[0004] Isolation of the engine cooling circuit from the vehicle HVAC circuit addresses each of the above-mentioned concerns. Regarding EGR cooler failures, as is known, EGR is used to reduce peak combustion temperatures by recirculating cooled exhaust gas. Portions of the exhaust gas are routed through a cooler then the cooled exhaust gases are reintroduced into the fresh charge air. The new mixture contains fewer oxygen molecules per mass which reduces the flame temperature during combustion thus reducing engine exhaust emissions. EGR reduces NO_x, a generic term for mono-nitrogen oxides NO and NO₂, which is produced from the reaction of nitrogen and oxygen gases in the air during internal engine combustion, especially at high temperatures. The reduction of NO_x occurs by taking exhaust gas from the exhaust manifold, circulating it through a cooler, and then mixing it with fresh air before the mixture enters the combustion chamber. The EGR cooler is a heat exchanger installed within the EGR circuit that utilizes engine coolant to absorb heat from the exhaust gas and thus cools the gas to a desired temperature prior to reentry into the combustion chamber. As prior art engine cooling and vehicle HVAC systems did not employ a coolant isolator to separate the coolant used in the engine cooling circuit from the coolant used in the vehicle HVAC circuit, air would get trapped within the shared coolant lines which led to reduced coolant levels and poor heat transfer properties within the EGR coolers. Poor heat transfer properties ensuing from the reduced coolant levels have led to the failure of multiple EGR cooler units.

SUMMARY OF THE DISCLOSURE

[0005] In one embodiment of the present disclosure a fluid isolation system for a vehicle is provided comprising a first fluid circuit coupled to an engine of the vehicle, the first fluid circuit providing a flow path through the engine for a first fluid; a second fluid circuit in a passenger compartment of the vehicle, the second fluid circuit providing a flow path for a second fluid; and a fluid isolator coupled to the first fluid circuit and the second fluid circuit, the fluid isolator structured to transfer heat from the first fluid to the second fluid, wherein the first and second fluids flow through the fluid isolator but do not contact one another. In one aspect of this embodiment the first fluid and the second fluid comprise at least one of water and coolant and the fluid isolator is a fluid-to-fluid heat exchanger, and wherein a temperature in the passenger compartment increases in response to the heat transferred from the first fluid to the second fluid. In another aspect of this embodiment the fluid isolation system further includes a first pump coupled to the first fluid circuit and a second pump coupled to the second fluid circuit, wherein the first pump facilitates movement of the first fluid within the first fluid circuit and the second pump facilitates movement of the second fluid within the second fluid circuit. In a variant of this aspect the fluid isolation system further includes a booster pump coupled to the second fluid circuit, the booster pump providing a supplemental pumping force in addition to a pumping force provided by the second pump, the supplemental pumping force facilitating movement of the second fluid within the second fluid circuit.

[0006] In another aspect of this embodiment the fluid isolation system further includes a surge tank in fluid communication with the first fluid circuit, the surge tank configured to receive fluid from the first fluid circuit in response to a characteristic of the first fluid exceeding a predetermined threshold and to provide fluid to the first fluid circuit in response to the characteristic of the first fluid falling below a predetermined threshold. In a variant of this aspect the fluid isolation system further includes a surge tank in fluid communication with the second fluid circuit, the surge tank configured to receive fluid from the second fluid circuit in response to a characteristic of the second fluid exceeding a predetermined threshold and to provide fluid to the second fluid circuit in response to the characteristic of the second fluid falling below the predetermined threshold. In yet another embodiment the fluid isolation system further includes at least one heating system including a fan, wherein the at least one heating system is disposed adjacent the passenger compartment and a portion of the second fluid moves through the at least one heating system wherein the fan moves air heated by the second fluid into the passenger compartment thereby increasing the temperature within the passenger compartment.

[0007] In another embodiment of the present disclosure a fluid isolation system is provided comprising a fluid isolator; a first fluid circuit coupled to an engine of a vehicle including a first fluid and a first section disposed in the fluid isolator wherein the first fluid moves through the fluid isolator by way of the first section; a second fluid circuit including a second fluid and a second section disposed in the fluid isolator wherein the second fluid moves through the fluid isolator by way of the second section; the fluid isolator structured to transfer heat from the first fluid to the second fluid in response to the first fluid and the second fluid moving through the fluid isolator, wherein the first fluid does not contact the second fluid; and at least one controller coupled to the first fluid circuit and the second fluid circuit and configured to control at least one flow characteristic of the first fluid separately from at least one flow characteristic of the second fluid. In one aspect of this embodiment the vehicle comprises a passenger compartment and an engine compartment, the first fluid circuit being disposed in the engine compartment and the second fluid circuit being disposed adjacent the passenger compartment. In a variant of this aspect the first fluid and the second fluid comprise at least one of water and coolant and the fluid isolator is a fluid-to-fluid heat exchanger, and wherein a temperature in the passenger compartment increases in response to the heat transferred from the first fluid to the second fluid.

[0008] In another aspect of this embodiment, the fluid isolation system further includes a first pump coupled to the second fluid circuit and a second pump coupled to the second fluid circuit, the second pump providing a supplemental pumping force in addition to a pumping force provided by the first pump to facilitate movement of the second fluid within the second fluid circuit. In yet another aspect of this embodiment, the at least one flow characteristic includes at least one of fluid temperature and fluid pressure. In a variant of this aspect, the fluid isolation system further includes a fluid reservoir in fluid communication with the first fluid circuit, the fluid reservoir configured to receive fluid from the first fluid circuit in response to the at least one flow characteristic of the first fluid exceeding a predetermined threshold and to provide fluid to the first fluid circuit in response to the at least one flow characteristic of the first fluid falling below the predetermined threshold. In a variant of this aspect the fluid isolation system further includes a fluid reservoir in fluid communication with the second fluid circuit, the fluid reservoir configured to receive fluid from the second fluid circuit in response to the at least one flow characteristic of the second fluid exceeding a predetermined threshold and to provide fluid to the second fluid circuit in response to the at least one flow characteristic of the second fluid falling below the predetermined threshold.

[0009] In yet another embodiment of the present disclosure a fluid isolation system is provided comprising: an engine disposed in a vehicle; an electronic controller disposed in the vehicle and configured to provide one or more control signals; a first fluid circuit including a first fluid that receives heat from the engine; a second fluid circuit including a second fluid that receives heat from the first fluid; at least one pump coupled to the electronic controller and in fluid communication with the second fluid circuit, wherein the at least one pump causes the second fluid to move through the second fluid circuit in response to receiving one or more control signals from the electronic controller; a fluid isolator coupled to the first fluid circuit and the second fluid circuit wherein the first fluid and the second fluid move through the fluid isolator such that heat from the first fluid is transferred to the second fluid, wherein the first fluid does not contact the second fluid and at least one flow characteristic of the first fluid is controlled separately from at least one flow characteristic of the second fluid. In one aspect of this embodiment, the vehicle comprises a passenger compartment and an engine compartment, the first fluid circuit being disposed in the engine compartment and the second fluid circuit being disposed adjacent the passenger compartment. In a variant of this aspect the first fluid and the second fluid comprise at least one of water and coolant and the fluid isolator is a fluid-to-fluid heat exchanger, and wherein a temperature in the passenger compartment increases in response to the heat transferred from the first fluid to the second fluid.

[0010] In another aspect of this embodiment, the fluid isolation system further includes a heating device coupled to the second fluid circuit and communicably coupled to the electronic controller, wherein the heating device provides supplemental heat to the second fluid in response to receiving one or more control signals from the electronic controller. In another aspect of this embodiment, the at least one flow characteristic includes at least one of fluid temperature and fluid pressure. In yet another aspect of this embodiment, the fluid isolation system further includes a fluid reservoir in fluid communication with the first fluid circuit, the fluid reservoir configured to receive fluid from the first fluid circuit in response to the at least one flow characteristic of the first fluid exceeding a predetermined threshold and to provide fluid to the first fluid circuit in response to the at least one flow characteristic of the first fluid falling below the predetermined threshold. In yet another aspect of this embodiment, the fluid isolation system further includes a fluid reservoir in fluid communication with the second fluid circuit, the fluid reservoir configured to receive fluid from the second fluid circuit in response to the at least one flow characteristic of the second fluid exceeding a predetermined threshold and to provide fluid to the second fluid circuit in response to the at least one flow characteristic of the second fluid falling below the predetermined threshold.

BRIEF DESCRIPTION OF THE DRAWINGS

[0011] The above-mentioned and other features of this disclosure and the manner of obtaining them will become more apparent and the disclosure itself will be better understood by reference to the following description of embodiments of the present disclosure taken in conjunction with the accompanying drawings, wherein:

[0012] FIG. 1 is a conceptual diagram of a prior art engine cooling and vehicle HVAC system.

[0013] FIG. 2 is a conceptual diagram of a coolant isolation system according to an embodiment of the present disclosure.

[0014] FIG. 3 is a conceptual side view of a vehicle having an HVAC system according to an embodiment of the present disclosure.

DETAILED DESCRIPTION OF EMBODIMENTS

[0015] The embodiments disclosed herein are not intended to be exhaustive or to limit the disclosure to the precise forms disclosed in the following detailed description. Rather, the embodiments were chosen and described so that others skilled in the art may utilize their teachings.

[0016] FIG. 1 is a conceptual diagram of a prior art engine cooling and vehicle HVAC system. Engine cooling and vehicle HVAC system 100 generally includes a plurality of engine cooling system components and a plurality of vehicle HVAC system components. The engine cooling system components generally include an Engine Control Module (ECM) 124, a water pump 112, a thermostat 114, a radiator 116, a transmission cooler 120, and a radiator fan 118. The vehicle HVAC system components generally include a rooftop air conditioning (A/C) unit 134, a front defroster 132, a street side floor heater 130, a curb side floor heater 128, a step heater 126, and a defroster heater 122. Engine 110 generally includes a cylinder head 138 and an engine block 136. Engine cooling and vehicle HVAC system 100 also includes conduit system 142 which facilitates circulation of coolant 140 through the plurality of engine cooling system components and the plurality of vehicle HVAC system components. Coolant 140 is generally a water-based liquid that includes antifreeze and anti-boil chemical additives which respectively lower the freezing point and raise the boiling point of water-based liquids. Coolant 140 includes chemical attributes that achieve freezing-point depression for cold environments and boiling- point elevation to allow higher coolant temperature such that coolant 140 can withstand the elevated internal temperatures of internal combustion engine 110. Conduit system 142 comprises a plurality of interconnecting hoses that form the supply lines and return lines in which coolant 140 flows.

[0017] Engine 110 further includes a plurality of internal passages (not shown) within cylinder head 138 and engine block 136 wherein coolant 140 circulates through engine 110 as is known in the art. Water pump 112, a standard centrifugal pump driven by a belt connected to the crankshaft of engine 110, causes coolant 140 to further circulate through engine 110 and throughout the plurality of engine cooling system components and the plurality of vehicle HVAC system components. As coolant 140 leaves engine block 136 and cylinder head 138 it flows through radiator 116 then into water pump 112 and circulates through other components until finally re-entering engine block 136 and cylinder head 138. As coolant 140 circulates through engine 110 and other engine cooling system components, thermostat 114 monitors and regulates the temperature of coolant 140. Radiator 116 provides additional coolant temperature regulation by removing heat from coolant 140 as it flows through radiator 116. Radiator 116 is a type of heat exchanger used to transfer heat from coolant 140 to the air blown through it by radiator fan 118 and external air streams 144 caused by movement of the vehicle. Radiator fan 118 is an axial fan that forces air through radiator 116 to facilitate the removal of heat from heated coolant 140. In other prior art configurations, coolant 140 flows through transmission cooler 120 prior to entry into radiator 116.

[0018] The engine cooling and vehicle HVAC system 100 depicted in FIG. 1 accomplishes engine cooling by utilizing water pump 112 to facilitate circulation of coolant 140 through passages within engine block 136 and cylinder head 138. As coolant 140 flows through the passages within engine block 136 and cylinder head 138, coolant 140 absorbs heat generated by internal combustion within engine 110. Conduit system 142 then routes heated coolant 140 through a plurality of interconnected hoses to radiator 116 which may be located in the front of the vehicle or any other location suitable to accomplish coolant heat transfer. As heated coolant 140 flows through thin passages within radiator 116 heated coolant 140 is cooled by both radiator fan 118 and air streams 144 entering the compartment (not shown) where radiator 116 resides. Air streams 144 generally enter the compartment via an air inlet mechanism, such as a grill (not shown), located typically in the front of the vehicle where high velocity streams of air are likely to traverse radiator 116. As cooled coolant 140 exits radiator 116 via conduit system 142, the cooled coolant 140 then flows past thermostat 114 which monitors the temperature of coolant 140 to ensure radiator 116 has adequately removed sufficient heat from coolant 140. Once coolant 140 is cooled, it returns to engine 110 to absorb more heat and the cycle repeats for the duration that engine 110 is operating.

[0019] Vehicles such as transit buses have large interior areas that require heating, ventilation, and air conditioning to ensure passenger comfort when seated in the interior areas. FIG. 1 of the present disclosure depicts a plurality of vehicle HVAC system components through which heated coolant 140 flows to heat the vehicle’s interior during cold weather conditions. Engine cooling and vehicle HVAC system 100 includes rooftop air conditioning (A/C) unit 134 which may be mounted at the top rear of the vehicle. In an alternate configuration as depicted in FIG. 3, rooftop A/C unit 134 may also include auxiliary coolant heater 214 and coolant booster pump 216 integrated therein. Street side floor heater 130 and curb side floor heater 128 are generally located inside the vehicle’s interior below passenger seating units and may be disposed approximately towards the middle or aft section of the vehicle. Front defroster 132 and defroster heater 122 are generally disposed in the front of the vehicle near the driver seating area while step heater 126 is generally disposed adjacent the vehicle’s passenger entry and exit areas to aid in defrosting or melting snow and ice that may accumulate during cold weather conditions.

[0020] The prior art engine cooling and vehicle HVAC system 100 of FIG. 1 accomplishes vehicle cabin warming at least in part by circulating heated coolant 140 from engine 110 through conduit system 142. In an alternate embodiment, as provided in FIG. 3, heated coolant 140 circulates through the plurality of HVAC system components by means of coolant supply line 310 and coolant return line 312. In FIG. 1, as heated coolant 140 circulates through conduit system 142 heat is transferred from the hot coolant to heater coil 146 disposed within the heater and defroster units. Supply fan 148 integrated within street side floor heater 130 and curb side floor heater 128 blow fresh air through heating coil 146 disposed within the heater and defroster units. The fresh air picks up heat by means of conduction via heated coolant 140 flowing through fluid tubes (not shown) within heater coil 146. In addition to the tubes, heater coil 146 may also include fins (not shown) attached to the tubes to facilitate the heat transfer. More particularly, supply fan 148 within street side floor heater 130 and curb side floor heater 128 circulate supply air through ductwork (not shown) in which air flows from supply fan 148 to the conditioned space within the vehicle interior. Likewise, front defroster 132 and defroster heater 122 function in substantially the same manner as the heater units, except that a portion of coolant 140 flowing through cylinder head 138 and water pump 112 is supplied directly to defroster heater 122. Additionally, front defroster 132 blows fresh air through heating coil 146 disposed within defroster heater 122 thereby defrosting front windshield 318 (FIG. 3) during cold weather conditions.

[0021] FIG. 2 provides an exemplary embodiment of the present disclosure designed to overcome one or more shortcomings of the prior art engine cooling and vehicle HVAC system 100 and/or offer features noted herein below. As shown in FIG. 2, coolant isolation system 200 does not circulate hot engine coolant through a single coolant loop such as conduit system 142 of engine cooling and vehicle HVAC system 100; rather coolant isolation system 200 comprises two independent coolant transfer circuits– vehicle HVAC circuit 202 and engine cooling circuit 204. Coolant isolation is facilitated by coolant isolator 206, which may be mounted, for example, on the driver’s side of engine 110 and disposed adjacent oil pan 146. Coolant isolator 206 is configured to facilitate heat transfer from the hot engine coolant circulating within engine cooling circuit 204 to the coolant circulating within vehicle HVAC circuit 202. In one embodiment, coolant isolator 206 comprises a water-to-water heat exchanger which includes a series of plates and fins (not shown) configured to ensure rapid coolant flow in order to facilitate efficient heat transfer. In one embodiment, coolant isolator 206 has a maximum coolant flow of 61.6 gallons per minute (GPM), an engine coolant heat rejection of 2300 BTU/min at 2100 RPM, and a heat transfer efficiency of greater than 98%. Coolant isolator 206 may be selected from a variety of commercially available water-to-water heat exchangers such as heat exchanger part number 34564131 manufactured by Alfa Laval. Referring to the independent coolant transfer circuits of FIG. 2, coolant isolator 206 further provides complete isolation of coolant 140 such that coolant circulating within engine cooling circuit 204 does not combine with or contact coolant circulating in vehicle HVAC circuit 202. [0022] As shown in FIG. 2, coolant isolation system 200 further includes HVAC surge tank 208, engine cooling surge tank 210, controller 212, auxiliary coolant heater 214, coolant booster pump 216, engine cooling conduit 218, HVAC conduit 220, and HVAC coolant pump 222. Due to the high temperature of coolant 140 and shorter circulation path within the two separate systems, pressures within the independent circuits of coolant isolation system 200 may be higher than in prior art systems, thus methods to depressurize the circuits without excessive coolant loss may be employed to maintain system integrity. HVAC surge tank 208 and engine cooling surge tank 210 provide overflow burp tank functionality by storing excess coolant released during system depressurization. Surge tanks 208 and 210 provide a mechanism to capture and reuse coolant released by vehicle HVAC circuit 202 and engine cooling circuit 204 during depressurization events. Therefore, as fluid temperatures cool down and system pressure lowers, surge tanks 208 and 210 cause excess fluid/coolant to return to their respective coolant circuits. HVAC coolant pump 222 causes coolant 140 to circulate within HVAC conduit 220 and through the plurality of system components that comprise vehicle HVAC circuit 202. In one embodiment, during vehicle interior heat-up assessment, comparative analysis of baseline versus isolated circuits showed that use of coolant isolation system 200 resulted in faster vehicle interior heating than the baseline circuit. Moreover, as shown in FIG. 2, an optional coolant booster pump 216 may be employed to provide additional circulation force and increased flow speed of coolant 140 through HVAC conduit 220. Likewise, an optional auxiliary coolant heater 214 may be included within vehicle HVAC circuit 202 to supplement coolant heat transferred by coolant isolator 206 and expedite warming of a vehicle’s interior during cold weather conditions. The use of coolant isolator 206 in conjunction with coolant booster pump 216 and auxiliary coolant heater 214 can significantly increase the available heat supplied to a parallel plumbed system such as vehicle HVAC circuit 202. This may permit increased heated coolant volume and flow through HVAC conduit 220 therefore ensuring efficient heat transfer through all heater coils 146 and enhanced warming of a vehicle’s interior.

[0023] FIG. 3 is a conceptual side view of a vehicle having an HVAC system according to an embodiment of the present disclosure, wherein, as shown in FIG. 2, coolant isolation system 200 entirely isolates coolant used to cool engine 110 from the coolant used to heat vehicle interior 318. Coolant isolator 206 isolates a controlled amount of engine coolant 140 while also transferring heat from coolant circulating in engine cooling conduit 218 to coolant circulating in HVAC conduit 220. As shown in FIG. 3, coolant from engine 314 supplies coolant 140 to rooftop A/C unit 134. Heated coolant 140 then flows via coolant supply line 310 to heater coil 146 within street side floor heater 130, curb side floor heater 128, step heater 126, front defroster 132 and defroster heater 120. Heated coolant 140 flows through tubes within heater coil 146 while heat transfer is accomplished by supply fan 148 blowing fresh air across the heater coil 146 such that warm air flows through ductwork (not shown) and into the transit bus interior 318. Coolant return line 312 provides a return path for coolant 140 to continuously re-enter coolant isolator 206 and absorb additional heat thereby causing coolant supply line 310 to consistently supply heated coolant 140 to the plurality of heater and defroster devices.

[0024] Referring again to FIG. 3, heated coolant 140 flows through coolant isolator 206, absorbs heat from engine cooling circuit 204, and ultimately flows through a plurality of heater and defroster devices. Each one of the plurality of heater and defroster devices adds some restriction resulting in decreased coolant flow. Likewise, the temperature of heated coolant 140 is reduced with each successive heat transfer resulting in heater coil 146 within the last heater device receiving coolant with a minimal heat load. Auxiliary coolant heater 214 as well as coolant booster pump 216 can be selectively positioned in order to maintain a nominal heat load for heated coolant 140 or increase the coolant’s temperature such that expedited warming may be accomplished. As shown in FIG. 3, rooftop A/C unit 134 may also include auxiliary coolant heater 214 and coolant booster pump 216 integrated therein. While in another aspect of this embodiment, as provided in FIG. 2, auxiliary coolant heater 214 and coolant booster pump 216 may be disposed in an alternate location in closer proximity to coolant isolator 206.

[0025] Coolant isolation system 200 provides additional opportunities for improved control of heat drawn by vehicle HVAC circuit 202. By separating the cabin and engine cooling circuits, coolant isolation system 200 permits coolant flow of engine coolant circuit 204 and coolant flow of vehicle HVAC circuit 202 to be controlled separately. In one embodiment, HVAC coolant pump 222 may be shut off in order to limit vehicle HVAC heat draw when engine 110 has not yet reached sufficient internal operating temperature. Implementation of the selective shut off feature for HVAC coolant pump 222 helps to reduce engine warm-up times during cold ambient conditions. In prior art cooling system applications, excessive heat draw during low engine operating temperatures have led to higher soot production and engine component failures due to excessive soot. Therefore, isolation of engine cooling circuit 204 from vehicle HVAC circuit 202 enables selective operation of HVAC coolant pump 222, which helps ensure sufficient engine operating temperature has been reached before HVAC heat draw is initiated, and mitigates engine component failures due to excessive soot production.

[0026] Coolant isolation system 200 of the present disclosure also ensures that coolant loss within the vehicle HVAC circuit 202 will not affect the performance of engine 110 and will not cause engine 110 to fail due to low coolant level. As indicated above, Exhaust Gas Recirculation coolers have had a history of failures due to low coolant level, thus engine component failures due to a loss of coolant in vehicle HVAC circuit 202 may be prevented by implementation of coolant isolation system 200. Moreover, implementation of coolant isolation system 200 to isolate engine cooling circuit 204 also reduces engine cooling system volume and overall complexity. This reduction in volume and simplified cooling circuit reduces the time required to fill and deaerate the engine cooling and vehicle HVAC system which in turn reduces system maintenance times for engine cooling circuit 204 and vehicle HVAC circuit 202.

[0027] In the foregoing specification, specific embodiments of the present disclosure have been described. However, one of ordinary skill in the art will appreciate that various modifications and changes can be made without departing from the scope of the disclosure as set forth in the claims below. Accordingly, the specification and figures are to be regarded in an illustrative rather than a restrictive sense. The benefits, advantages, solutions to problems, and any element(s) that may cause any benefit, advantage, or solution to occur or become more pronounced are not to be construed as critical, required, or essential features or elements of any or all the claims. The invention is defined solely by the appended claims including any amendments made during the pendency of this application and all equivalents of those claims as issued.

Claims

CLAIMS 1. A fluid isolation system for a vehicle comprising:

a first fluid circuit coupled to an engine of the vehicle, the first fluid circuit providing a flow path through the engine for a first fluid;

a second fluid circuit in a passenger compartment of the vehicle, the second fluid circuit providing a flow path for a second fluid; and

a fluid isolator coupled to the first fluid circuit and the second fluid circuit, the fluid isolator structured to transfer heat from the first fluid to the second fluid, wherein the first and second fluids flow through the fluid isolator but do not contact one another.

2. The fluid isolation system of claim 1, wherein the first fluid and the second fluid comprise at least one of water and coolant and the fluid isolator is a fluid-to-fluid heat exchanger, and wherein a temperature in the passenger compartment increases in response to the heat transferred from the first fluid to the second fluid.

3. The fluid isolation system of claim 1, further including a first pump coupled to the first fluid circuit and a second pump coupled to the second fluid circuit, wherein the first pump facilitates movement of the first fluid within the first fluid circuit and the second pump facilitates movement of the second fluid within the second fluid circuit.

4. The fluid isolation system of claim 4, further including a booster pump coupled to the second fluid circuit, the booster pump providing a supplemental pumping force in addition to a pumping force provided by the second pump, the supplemental pumping force facilitating movement of the second fluid within the second fluid circuit.

5. The fluid isolation system of claim 1, further including a surge tank in fluid

communication with the first fluid circuit, the surge tank configured to receive fluid from the first fluid circuit in response to a characteristic of the first fluid exceeding a predetermined threshold and to provide fluid to the first fluid circuit in response to the characteristic of the first fluid falling below a predetermined threshold.

6. The fluid isolation system of claim 5, further including a surge tank in fluid communication with the second fluid circuit, the surge tank configured to receive fluid from the second fluid circuit in response to a characteristic of the second fluid exceeding a predetermined threshold and to provide fluid to the second fluid circuit in response to the characteristic of the second fluid falling below the predetermined threshold.

7. The fluid isolation system of claim 1, further including at least one heating system including a fan, wherein the at least one heating system is disposed adjacent the passenger compartment and a portion of the second fluid moves through the at least one heating system wherein the fan moves air heated by the second fluid into the passenger compartment thereby increasing the temperature within the passenger compartment.

8. A fluid isolation system comprising:

a fluid isolator;

a first fluid circuit coupled to an engine of a vehicle including a first fluid and a first section disposed in the fluid isolator wherein the first fluid moves through the fluid isolator by way of the first section;

a second fluid circuit including a second fluid and a second section disposed in the fluid isolator wherein the second fluid moves through the fluid isolator by way of the second section;

the fluid isolator structured to transfer heat from the first fluid to the second fluid in response to the first fluid and the second fluid moving through the fluid isolator, wherein the first fluid does not contact the second fluid; and

at least one controller coupled to the first fluid circuit and the second fluid circuit and configured to control at least one flow characteristic of the first fluid separately from at least one flow characteristic of the second fluid.

9. The fluid isolation system of claim 8, wherein the vehicle comprises a passenger compartment and an engine compartment, the first fluid circuit being disposed in the engine compartment and the second fluid circuit being disposed adjacent the passenger

compartment.

10. The fluid isolation system of claim 9, wherein the first fluid and the second fluid comprise at least one of water and coolant and the fluid isolator is a fluid-to-fluid heat exchanger, and wherein a temperature in the passenger compartment increases in response to the heat transferred from the first fluid to the second fluid.

11. The fluid isolation system of claim 8, further including a first pump coupled to the second fluid circuit and a second pump coupled to the second fluid circuit, the second pump providing a supplemental pumping force in addition to a pumping force provided by the first pump to facilitate movement of the second fluid within the second fluid circuit.

12. The fluid isolation system of claim 8, wherein the at least one flow characteristic includes at least one of fluid temperature and fluid pressure.

13. The fluid isolation system of claim 11, further including a fluid reservoir in fluid communication with the first fluid circuit, the fluid reservoir configured to receive fluid from the first fluid circuit in response to the at least one flow characteristic of the first fluid exceeding a predetermined threshold and to provide fluid to the first fluid circuit in response to the at least one flow characteristic of the first fluid falling below the predetermined threshold.

14. The fluid isolation system of claim 11, further including a fluid reservoir in fluid communication with the second fluid circuit, the fluid reservoir configured to receive fluid from the second fluid circuit in response to the at least one flow characteristic of the second fluid exceeding a predetermined threshold and to provide fluid to the second fluid circuit in response to the at least one flow characteristic of the second fluid falling below the predetermined threshold.

15. A fluid isolation system comprising:

an engine disposed in a vehicle;

an electronic controller disposed in the vehicle and configured to provide one or more control signals;

a first fluid circuit including a first fluid that receives heat from the engine;

a second fluid circuit including a second fluid that receives heat from the first fluid; at least one pump coupled to the electronic controller and in fluid communication with the second fluid circuit, wherein the at least one pump causes the second fluid to move through the second fluid circuit in response to receiving one or more control signals from the electronic controller;

a fluid isolator coupled to the first fluid circuit and the second fluid circuit wherein the first fluid and the second fluid move through the fluid isolator such that heat from the first fluid is transferred to the second fluid, wherein the first fluid does not contact the second fluid and at least one flow characteristic of the first fluid is controlled separately from at least one flow characteristic of the second fluid.

16. The fluid isolation system of claim 15, wherein the vehicle comprises a passenger compartment and an engine compartment, the first fluid circuit being disposed in the engine compartment and the second fluid circuit being disposed adjacent the passenger

compartment.

17. The fluid isolation system of claim 16, wherein the first fluid and the second fluid comprise at least one of water and coolant and the fluid isolator is a fluid-to-fluid heat exchanger, and wherein a temperature in the passenger compartment increases in response to the heat transferred from the first fluid to the second fluid.

18. The fluid isolation system of claim 15, further including a heating device coupled to the second fluid circuit and communicably coupled to the electronic controller, wherein the heating device provides supplemental heat to the second fluid in response to receiving one or more control signals from the electronic controller.

19. The fluid isolation system of claim 15, wherein the at least one flow characteristic includes at least one of fluid temperature and fluid pressure.

20. The fluid isolation system of claim 15, further including a fluid reservoir in fluid communication with the first fluid circuit, the fluid reservoir configured to receive fluid from the first fluid circuit in response to the at least one flow characteristic of the first fluid exceeding a predetermined threshold and to provide fluid to the first fluid circuit in response to the at least one flow characteristic of the first fluid falling below the predetermined threshold.

21. The fluid isolation system of claim 15, further including a fluid reservoir in fluid communication with the second fluid circuit, the fluid reservoir configured to receive fluid from the second fluid circuit in response to the at least one flow characteristic of the second fluid exceeding a predetermined threshold and to provide fluid to the second fluid circuit in response to the at least one flow characteristic of the second fluid falling below the predetermined threshold.