TWO PHASE OIL COOLING SYSTEM
The present disclosure provides a two phase oil cooling system for a work vehicle. The system includes a condenser, an evaporator, a refrigerant path, and a pump. The condenser cools a refrigerant from vapor form to liquid form. The evaporator exchanges heat between a first fluid of the work vehicle and the refrigerant, and heats the refrigerant from liquid form to vapor form. The refrigerant path comprises a first refrigerant path thermally coupling the condenser to the evaporator and a second refrigerant path thermally coupling the evaporator to the condenser. The refrigerant flows through the refrigerant path. The pump is positioned in the first refrigerant path for pumping the refrigerant from the condenser to the evaporator, such that the evaporator is downstream of the pump and the condenser is downstream of the evaporator.
N/A
FIELD OF THE DISCLOSUREThe present disclosure relates generally to a cooling system applied to a work vehicle.
BACKGROUND OF THE DISCLOSUREThe off-highway industry uses a variety of rotating components: transmissions, axles, e-machines, hydraulic pumps and motors, etc. These components may use oil as a working fluid and/or for lubrication and cooling. A rotating component of a work vehicle, such as axle or transmission, generates heat while in operation. Conventionally, the heat is partially removed by a cooling system/circuit, including a radiator coupled to the work vehicle, a cooling fan, and an oil path. A hot cooling oil from the rotating component flows into the radiator and is cooled by the radiator due to the cooling fan providing an air flow passing through a series of heat dissipation components of the radiator. The cooled cooling oil later flow back to the rotating component. However, since the oil is typically pumped outside the rotating component to the remote single phase oil-to-air heat exchanger for cooling, this cooling circuit is prone to leaks, contamination, pumping losses and has a low heat transfer coefficient.
SUMMARY OF THE DISCLOSUREThe present disclosure includes a two phase oil cooling system that leverages the advantages of two-phase refrigerant applied on oil cooling which has significantly higher heat transfer coefficient. In addition, the present disclosure has the advantage of distributed heat loads from several components and does not require that oil be pumped to a remote cooling system.
According to an aspect of the present disclosure, a two phase oil cooling system is provided for a work vehicle. The two phase oil cooling system includes a condenser, an evaporator, a refrigerant path, and a pump. The condenser cools a refrigerant from vapor form to liquid form. The evaporator exchanges heat between a first fluid of the work vehicle and the refrigerant, thereby heating the refrigerant from liquid form to vapor form. The refrigerant path comprises a first refrigerant path thermally coupling the condenser to the evaporator and a second refrigerant path thermally coupling the evaporator to the condenser. The refrigerant flows through the refrigerant path. The pump is positioned in the first refrigerant path for pumping the refrigerant from the condenser to the evaporator, such that the evaporator is downstream of the pump and the condenser is downstream of the evaporator.
According to another aspect of the present disclosure, a two phase oil cooling system is provided for a work vehicle. The two phase oil cooling system includes a condenser, an evaporator, and a refrigerant path. The condenser cools a refrigerant from vapor form to liquid form. The evaporator is positioned below the condenser and exchanges heat between an oil of a rotating component of the work vehicle and the refrigerant, thereby heating the refrigerant from liquid form to vapor form. The refrigerant path thermally couples the condenser to the evaporator. The refrigerant flows in bi-directions in the refrigerant path, driven by difference of densities of the refrigerant responsive to temperatures of the refrigerant within the refrigerant path, within the condenser, and within the evaporator.
The present disclosure also provides a method for cooling a rotating component. The method includes: pumping a refrigerant at least partial in liquid form to an evaporator and moving the refrigerant at least partial in vapor form to a condenser via the pumping such that a pressure of the refrigerant flowing into the evaporator is higher than another pressure of the refrigerant flowing into the condenser; absorbing a heat from an oil in the rotating component by the evaporator to evaporate the refrigerant from liquid form to vapor form; and cooling the refrigerant at least partial in vapor form via the condenser.
Other features and aspects will become apparent by consideration of the detailed description and accompanying drawings.
The detailed description of the drawings refers to the accompanying figures in which:
Referring to
In a path (suction line) between the evaporator 14′ and the compressor 24′, the refrigerant is at a low pressure and low temperature. In order to run the compressor 24′ properly, the refrigerant is in vapor form (gas or superheat gas). When the refrigerant reaches the compressor 24′, the compressor 24′ compresses the refrigerant in vapor form, such that the refrigerant in a path between the compressor 24′ and the condenser 12′ is at a high pressure (PH) and high temperature (may be superheat). When the refrigerant reaches condenser 12′, the condenser 12′ cools the temperature of the refrigerant and change it into liquid form via a fan (not shown). The fan provides a first air flow AF1′ passing through a heat dissipation element of the condenser 12′ to remove the heat from the condenser 12′. Refrigerant at the exit of the condenser 12′ must be saturated or subcooled liquid for smooth operation of thermal expansion valve (TXV). In a path between the condenser 12′ and the thermal expansion valve (TXV), the refrigerant is still at the high pressure.
The thermal expansion valve (TXV) later collects the refrigerant from the condenser 12′. In the thermal expansion valve (TXV), the pressure of the refrigerant drastically decreases. The temperature of the refrigerant may also drop. Therefore, in a path between the thermal expansion valve (TXV) and the evaporator 14′, the refrigerant is at a low pressure (PL). The low pressure refrigerant flows into the evaporator 14′. Another fan (not shown) adjacent to the evaporator 14′ provides a second air flow AF2′ (indoor) passing through a heat exchange element of the evaporator 14′. The heat of the second air flow AF2′ is absorbed by the refrigerant, because refrigerant in liquid form changing into vapor form requires latent heat (energy potential). Again, the refrigerant is discharged by the evaporator 14′ and flows into the compressor 24′.
A first air flow AF1 is driven by a condenser fan 80 to cool the condenser 12, such that the refrigerant in vapor form flowing from the second refrigerant path 164 can be transformed into liquid form. The pump 20 pumps the refrigerant into the evaporator 14. A first oil flow OF1 flowing from or in the rotating component, transfers the heat to the refrigerant within the evaporator 14. With the vaporization of the refrigerant, the first oil flow OF1 is therefore cooled. The heated refrigerant later exits from the evaporator 14 and enters to the condenser 12 to be liquidized.
The following embodiments include multiple variations derivative from
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It is noted that the features in the second and third embodiments can be combined (referring to
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When the energy recycling unit 30 includes the secondary pump 34, the secondary pump 34 may pump another liquid to obtain additional functions. For example, the secondary pump 34 can be an oil pump 66 as shown in
It is noted that, the energy recycling unit 30 can also be applied to the second refrigerant path 164 in the configuration of
With reference to
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The evaporator 14 is positioned outside the rotating component 60 makes an operator to maintain easily. The filtration process also extends the life of the rotating component 60. The sixth embodiment of the two phase oil cooling system 10 may be used in a work vehicle that normally has a severe duty application.
Referring to
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The antifreeze 92 in this embodiment is glycol. The antifreeze 92 absorbs heat in the first, second, third heat exchangers 902, 904, 906 from the oil of the first, second, and third rotating components 602, 604, 606. The heated antifreeze 92 then flows to the evaporator 14 to heat the refrigerant from liquid form to vapor form such that the cooled antifreeze 92 can flow to the heat exchangers 902, 904, 906 again to cool the oil in the first, second, third rotating components 602, 604, 606.
Alternatively, referring to
In
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The two phase oil cooling system 10 further includes a temperature sensor 122 to measure the temperature of the refrigerant in at least one of the condenser 12, the evaporators 14, and the refrigerant path 16. In the embodiment as shown in
The present disclosure also provides a method for cooling a rotating component:
Step 1: pumping a refrigerant at least partial in liquid form to an evaporator and further to a condenser via a pump such that a pressure of the refrigerant flowing into the evaporator is higher than another pressure of the refrigerant flowing into the condenser.
When the pump is a liquid pump, step 1 also includes separating the refrigerant in vapor form from the refrigerant in liquid form to permit the refrigerant in liquid form to flow through the pump. The refrigerant in vapor form is disposed in two ways:
(1) diverting the refrigerant in vapor form back to the condenser through a reverse refrigerant path; or
(2) compressing the refrigerant in vapor form to the evaporator via a compressor.
Step 2: absorbing a heat from an oil of the rotating component by the evaporator to evaporate the refrigerant from liquid form to vapor form.
Step 2 also includes submerging the evaporator in the oil within the rotating component. In the operation of the rotating component, the oil is driven to flow along at least one surface of the evaporator to increase heat exchange rate.
Alternatively, step 2 includes pumping the oil by an oil pump from the rotating component to the evaporator to exchange the heat between the oil and the refrigerant. This step also includes filtering the oil via an oil filter utilizing the oil pressure created by the oil pump.
Step 2 may also include recycling energy from the refrigerant that exits from the evaporator. The turbine is driven by the refrigerant.
Step 3: cooling the refrigerant at least partial in vapor form via the condenser.
The steps mentioned above will repeat to cool the oil in the rotating component.
Without in any way limiting the scope, interpretation, or application of the claims appearing below, a technical effect of one or more of the example embodiments disclosed herein is to cool the oil in the rotating component with higher heat transfer coefficient refrigerant to reach better cooling performance. Another technical effect of one or more of the example embodiments disclosed herein is to distribute the heat loads from one or more rotating components without the oil being pumped to a remote distance of the work vehicle. Another technical effect of one or more of the example embodiments disclosed herein is to decrease the chance of oil leakage.
As used herein, unless otherwise limited or modified, lists with elements that are separated by conjunctive terms (e.g., “and”) and that are also preceded by the phrase “at least one of” or “one or more of” indicate configurations or arrangements that potentially include individual elements of the list, or any combination thereof. For example, “at least one of A, B, and C” or “one or more of A, B, and C” indicates the possibilities of only A, only B, only C, or any combination of two or more of A, B, and C (e.g., A and B; B and C; A and C; or A, B, and C)
While the above describes example embodiments of the present disclosure, these descriptions should not be viewed in a limiting sense. Rather, other variations and modifications may be made without departing from the scope and spirit of the present disclosure as defined in the appended claims.
Claims
1. A two phase oil cooling system for a work vehicle, comprising:
- a condenser configured to cool a refrigerant from vapor form to liquid form;
- an evaporator configured to exchange heat between a first fluid of the work vehicle and the refrigerant, thereby heating the refrigerant from liquid form to vapor form;
- a refrigerant path comprising a first refrigerant path thermally coupling the condenser to the evaporator and a second refrigerant path thermally coupling the evaporator to the condenser, the refrigerant configured to flow through the refrigerant path; and
- a pump positioned in the first refrigerant path for pumping the refrigerant from the condenser to the evaporator, such that the evaporator is downstream of the pump and the condenser is downstream of the evaporator.
2. The two phase oil cooling system for a work vehicle of claim 1, wherein the first fluid is an oil of a rotating component of the work vehicle.
3. The two phase oil cooling system for a work vehicle of claim 2, wherein the evaporator is at least partially submerged in the oil within the rotating component of the work vehicle.
4. The two phase oil cooling system for a work vehicle of claim 3, wherein when the rotating component operates, the oil is driven to flow with turbulence over at least one surface of the evaporator to increase heat exchange rate.
5. The two phase oil cooling system for a work vehicle of claim 2, wherein the evaporator is positioned outside the rotating component, and the oil of the rotating component is in fluid communication with the rotating component and the evaporator via a first oil path and a second oil path which couple the rotating component to the evaporator.
6. The two phase oil cooling system for a work vehicle of claim 5, wherein the evaporator comprises a refrigerant passage through which flows the refrigerant and the refrigerant passage thermally couples the first refrigerant path to the second refrigerant path, and an oil passage through which flows the oil and the oil passage thermally couples the first oil path to the second oil path, and the refrigerant passage and the oil passage are at least in proximity to or engaged with one another to exchange heat.
7. The two phase oil cooling system for a work vehicle of claim 6, comprising an oil pump positioned in the first oil path, and the oil pump pumping the oil from the rotating component to the evaporator.
8. The two phase oil cooling system for a work vehicle of claim 7, comprising an oil filter positioned in one of the first oil path and the second oil path to filter the oil of the rotating component.
9. The two phase oil cooling system for a work vehicle of claim 1, wherein the pump is a two-phase flow pump, pumping the refrigerant in liquid and vapor forms.
10. The two phase oil cooling system for a work vehicle of claim 1, comprising a separator positioned in the first refrigerant path between the condenser and the pump and configured to separate the refrigerant in vapor form from the refrigerant in liquid form to permit the refrigerant in liquid form to flow through the pump.
11. The two phase oil cooling system for a work vehicle of claim 10, comprising a reverse refrigerant path coupling the separator to the second refrigerant path, through the reverse refrigerant path flows the refrigerant in vapor form from the separator to the second refrigerant path.
12. The two phase oil cooling system for a work vehicle of claim 11, comprising a reverse flow control valve positioned in the reverse refrigerant path.
13. The two phase oil cooling system for a work vehicle of claim 10, comprising a compressor path coupling the separator to the first refrigerant path, and a compressor positioned in the compressor path, the compressor compressing the refrigerant that is vapor form flowing from the separator through the compressor path to the evaporator, and the pump pumping the refrigerant that is liquid form flowing from the separator through the first refrigerant path to the evaporator.
14. The two phase oil cooling system for a work vehicle of claim 13, comprising an energy recycling unit positioned in the second refrigerant path, the energy recycling unit including a turbine driven by the refrigerant.
15. The two phase oil cooling system for a work vehicle of claim 14, wherein the energy recycling unit comprises one of a secondary pump and a generator coupled to the turbine.
16. The two phase oil cooling system for a work vehicle of claim 1, comprising an energy recycling unit positioned in the second refrigerant path, the energy recycling unit including a turbine driven by the refrigerant, and one of a secondary pump and generator coupled to the turbine.
17. The two phase oil cooling system for a work vehicle of claim 2, comprising a flow control valve positioned in the first refrigerant path between the pump and the evaporator, the flow control valve operating based on a temperature of the oil.
18. The two phase oil cooling system for a work vehicle of claim 17, comprising more than one of the evaporators and more than one rotating components having oils, wherein the first refrigerant path divides a plurality of sub-first refrigerant paths, the second refrigerant path divides a plurality of sub-second refrigerant paths, and each of the evaporators is coupled to one of the sub-first refrigerant paths and to one of the sub-second refrigerant paths and exchanges heat between oil of one of the rotating components and the refrigerant flowing through the evaporator.
19. The two phase oil cooling system for a work vehicle of claim 18, comprising more than one flow control valves, each of which is positioned respective to one of the sub-first refrigerant paths, the flow control valves are configured to control the refrigerant flowing in the sub-first refrigerant paths.
20. The two phase oil cooling system for a work vehicle of claim 1, comprising a condenser fan configured to cool the condenser and a pump-condenser fan control logic coupled to the pump and the condenser, and the pump-condenser fan control logic configured to regulate the condenser to cool the refrigerant before the pump pumping the refrigerant.
21. The two phase oil cooling system for a work vehicle of claim 1, comprising a heat exchanger configured to exchange heat between the first fluid and an oil of a rotating component of the work vehicle.
22. The two phase oil cooling system for a work vehicle of claim 21, wherein the first fluid is an antifreeze, the evaporator is positioned outside the rotating component, the first fluid is in fluid communication with the evaporator and the heat exchanger via an antifreeze path which couples the evaporator to the heat exchanger.
23. The two phase oiling cooling system for a work vehicle of claim 22, further comprising an antifreeze pump positioned in the antifreeze paths and configured to pump the antifreeze to the evaporator.
24. The two phase oiling cooling system for a work vehicle of claim 1, comprising a condenser fan configured to cool the condenser, the condenser fan positioned downstream of the evaporator and upstream of the condenser such that the condenser fan is at least partially driven by a volumetric expansion of the refrigerant.
25. A two phase oil cooling system for a work vehicle, comprising:
- a condenser configured to cool a refrigerant from vapor form to liquid form;
- an evaporator positioned below the condenser and configured to exchange heat between an oil of a rotating component of the work vehicle and the refrigerant, thereby heating the refrigerant from liquid form to vapor form; and
- a refrigerant path thermally coupling the condenser to the evaporator, the refrigerant configured to flow in bi-directions in the refrigerant path, driven by difference of densities of the refrigerant responsive to temperatures of the refrigerant within the refrigerant path, within the condenser, and within the evaporator.
26. A method for cooling a rotating component, comprising:
- pumping a refrigerant at least partial in liquid form to an evaporator and moving the refrigerant at least partial in vapor form to a condenser via the pumping such that a pressure of the refrigerant flowing into the evaporator is higher than another pressure of the refrigerant flowing into the condenser;
- absorbing a heat from an oil in the rotating component by the evaporator to evaporate the refrigerant from liquid form to vapor form; and
- cooling the refrigerant at least partial in vapor form via the condenser.
Type: Application
Filed: Mar 28, 2019
Publication Date: Oct 1, 2020
Inventors: STEVEN R. WHITEMAN (DUBUQUE, IA), REGINALD M. BINDL (BETTENDORF, IS), STEVEN R. SASS (DUBUQUE, IA), ZAKIR H. FARUQUEE (ASBURY, IA), ERIC R. ANDERSON (AMES, IA)
Application Number: 16/367,551