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FORM 2
THE PATENTS ACT, 1970
[39 OF 1970]
&
THE PATENTS RULES, 2003
COMPLETE SPECIFICATION
[See section 10; rule 13]
TITLE: “A TRACTION COOLING SYSTEM OF A VEHICLE”
Name and Address of the Applicant:
TATA MOTORS LIMITED, Bombay House, 24 Homi Mody Street, Hutatma Chowk, Mumbai 400 001, Maharashtra, India
Nationality: Indian
The following specification particularly describes the invention and the manner in which it is to be performed.
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TECHNICAL FIELD
[001] Present disclosure generally relates to a field of automobiles. Particularly, but not exclusively, the present disclosure relates to an electric vehicle. Further, embodiments of the present disclosure relate to a traction cooling system of the electric vehicle.
BACKGROUND OF THE DISCLOSURE 5
[002] Generally, electric vehicles (EVs) are equipped with a traction system to drive the vehicle. The traction system includes a traction motor and a plurality of electrical components, such as at least one inverter, at least one DC-DC converter, and a motor control unit. Further, conventionally the electric vehicle includes a High-Voltage (HV) battery unit configured to supply power to the traction motor. The at least one inverter is configured to convert direct 10 current (DC) power received from the HV battery unit to alternate current (AC) power that is required to operate the traction motor. Further, the at least one DC-DC converter is configured to convert the high-voltage DC power received from the HV battery unit to a low-voltage DC power. Furthermore, the motor control unit regulates the power being supplied to the traction motor. 15
[003] During the operation of the traction motor, the traction motor generates heat. Further, the flow of current through the plurality of electrical components generates heat due to Joule heating, i.e., due to internal resistance offered by the plurality of electrical components for the flow of current. The traction system is thus cooled using a traction cooling system. The traction cooling system includes a coolant flow path having a radiator disposed upstream and fluidically 20 connected to the traction system. The radiator is configured to receive hot coolant from the traction system for heat exchange. Further, the traction cooling system includes a pump fluidically disposed in the first coolant flow path and is configured to circulate the coolant received from the radiator at a predetermined pressure, in the first coolant flow path, to cool the traction system. 25
[004] In conventional traction cooling systems, the electrical components tend to offer higher resistance to the flow of the coolant. This causes a pressure drop in the coolant flow across the first coolant flow path, which limits the flow of the coolant through the plurality of electrical components. Consequently, the plurality of electrical components and the motor may not receive sufficient coolant, particularly at an elevated ambient temperature, i.e., in an area 30 having elevated temperature. This would affect the efficiency of the motor and the plurality of electrical components. Further, due to the low flow rate of the coolant, the coolant heats up
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quickly and necessitates faster cooling. This necessitates in high power to operate a radiator cooling fan, i.e., the radiator cooling fan operates at its peak capacity, consequently, affecting the range of the EV. Further, the radiator cooling fan generates high Noise, Vibration, and Harshness (NVH) while operating at its peak capacity. Such excess NVH creates discomfort to the passengers and would reduce the life span of the radiator. Increasing the capacity of the 5 pump cannot provide the required cooling as the increase in coolant flow rate increases the pressure drop proportionately, resulting in low coolant flow through the radiator and reduced limiting ambient temperature.
[005] The drawbacks/difficulties/disadvantages/limitations of the conventional techniques explained in the background section are just for exemplary purposes and the disclosure would 10 never limit its scope only to such limitations. A person skilled in the art would understand that this disclosure and below mentioned description may also solve other problems or overcome the other drawbacks/disadvantages of the conventional arts which are not explicitly captured above.
SUMMARY OF THE DISCLOSURE 15
[006] One or more shortcomings of the conventional system are overcome by a traction cooling system as described in the specification and claims. Additional features and advantages are realized through the techniques of the present disclosure. Other embodiments and aspects of the disclosure are described in detail herein and are considered a part of the claimed disclosure. 20
[007] In a non-limiting embodiment of the disclosure, a traction cooling system of a vehicle is disclosed. The traction cooling system includes a radiator defined with an inlet and an outlet. Further, the traction cooling system includes a first coolant flow path fluidically connected to the outlet of the radiator and a traction system, wherein the traction system comprises a plurality of electrical components and a traction motor. Furthermore, the traction cooling system 25 includes a pump fluidically disposed in the first coolant flow path configured to supply coolant at a first predetermined pressure. In addition, the traction cooling system includes a bypass flow path defined with a first end and a second end. The first end is fluidically connected to the pump, and the second end is fluidically connected to the inlet of the radiator. The bypass flow path is configured to maintain the same pressure drop of the coolant at a second 30 predetermined pressure drop across the bypass flow path and the first coolant flow path and a
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traction system, to maintain a predetermined rate of flow of the coolant through the first coolant flow path and the traction system. [008] In an embodiment, the plurality of electrical components comprises at least one DC-DC converter, at least one inverter, and a motor control unit.
[009] In an embodiment, the bypass flow path is one of: at least one conduit, at least one 5 channel, and at least one duct.
[0010] In an embodiment, each of the plurality of electrical components, and the traction motor comprises a plurality of cooling jackets, fluidly connected to the first coolant flow path, wherein the plurality of cooling jackets are structured to absorb heat from each of the plurality of electrical components and the traction motor, and exchange the heat with the coolant in the 10 traction system.
[0011] In an embodiment, the traction cooling system comprising a storage tank, fluidically connected to the radiator, and structured to store and supply the coolant to the first coolant flow path, when the volume of the coolant in the first coolant flow path is below a predetermined volume. 15
[0012] In another non-limiting embodiment of the present disclosure, a vehicle is disclosed. The vehicle includes a traction system having a traction motor. Further, the traction system includes a plurality of electrical components connected to the traction motor. The vehicle further includes a power source connected to the plurality of electrical components. In addition, the vehicle includes a traction cooling system. The traction cooling system includes a radiator 20 defined with an inlet and an outlet. Further, the traction cooling system includes a first coolant flow path fluidically connected to the outlet of the radiator and a traction system. Furthermore, the traction cooling system includes a pump fluidically disposed in the first coolant flow path configured to supply coolant at a first predetermined pressure. In addition, the traction cooling system includes a bypass flow path defined with a first end and a second end. The first end is 25 fluidically connected to the pump, and the second end is fluidically connected to the inlet of the radiator. The bypass flow path is configured to maintain the pressure drop of the coolant at a second predetermined pressure drop across the bypass flow path and the traction system to maintain a predetermined rate of flow of the coolant through the traction system.
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[0013] In an embodiment, the plurality of electrical components comprises at least one DC-DC converter, at least one inverter, and a motor control unit.
[0014] In an embodiment, the bypass flow path comprises is one of: at least one conduit, at least one channel, at least one duct.
[0015] In an embodiment, comprising a storage tank, fluidically connected to the radiator, and 5 structured to store and supply the coolant to the first coolant flow path, when the volume of the coolant in the first coolant flow path is below a predetermined volume.
[0016] In another non-limiting embodiment of the present disclosure, a method to cool a plurality of electrical components and a traction motor of a vehicle is disclosed. The method includes supplying a coolant at a first predetermined pressure, by a pump, to a coolant flow 10 path. The first coolant flow path is fluidically connected to an outlet of a radiator, the plurality of electrical components and the traction motor. Further, the method includes supplying the coolant, by the pump, to a bypass flow path. The bypass flow path is defined with a first end and a second end. The first end is fluidically connected to the pump and the second end is fluidically connected to the inlet of the radiator. The bypass flow path is configured to maintain 15 the pressure drop of the coolant at a second predetermined pressure drop across the first coolant flow path and the bypass flow path, to maintain a predetermined rate of flow of the coolant through the first coolant flow path.
[0017] In an embodiment, the traction cooling system of the present disclosure aids in maintaining the constant pressure drop of the coolant at the second predetermined pressure 20 drop across the bypass flow path and the traction system, thereby increasing the limiting ambient temperature of the traction cooling system, because of increased coolant flow from the radiator, as the heat dissipation capacity increases. Such increase in the limiting ambient temperature enables the vehicle to operate in harsh climatic conditions. Since the constant pressure drop of the coolant is maintained across the bypass flow path and the first coolant flow 25 path, the desired flow rate through the traction system can be achieved without any substantial pressure drop, thereby increasing the efficiency of the traction motor and the plurality of electrical components. Further, the hot coolant received from the traction system is mixed with the cooled coolant from the bypass flow path. This reduces the temperature of the coolant entering the inlet of the radiator, thereby reducing the power required to operate the radiator 30 cooling fan, and consequently, increasing the range of EV. Due to the radiator cooling fan operating at low power, the Noise, Vibration, and Harshness generated by the radiator is also
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low. Such low NVH increases comfort of the passengers and enhances life span of the radiator cooling fan. [0018] The foregoing summary is illustrative only and is not intended to be in any way limiting. In addition to the illustrative aspects, embodiments, and features described above, further aspects, embodiments, and features will become apparent by reference to the drawings and the 5 following detailed description.
BRIEF DESCRIPTION OF THE ACCOMPANYING DRAWINGS
[0019] The novel features and characteristics of the disclosure are set forth in the appended description. The disclosure itself, however, as well as a preferred mode of use, further objectives, and advantages thereof, will best be understood by reference to the following 10 detailed description of an illustrative embodiment when read in conjunction with the accompanying figures. One or more embodiments are now described, by way of example only, with reference to the accompanying figures wherein like reference numerals represent like elements and in which:
[0020] Figure 1 is a schematic layout of a traction cooling system of a vehicle, according to 15 an embodiment of the present disclosure;
[0021] Figure 2 illustrates a perspective view of the traction cooling system of Figure 1, according to an embodiment of the present disclosure;
[0022] Figure 3a illustrates a rear perspective view of a portion of the vehicle depicting the traction cooling system with a first coolant flow path and a bypass flow path, according to an 20 embodiment of the present disclosure;
[0023] Figure 3b illustrates a front perspective view of Figure 3a depicting a radiator and a storage tank, according to an embodiment of the present disclosure;
[0024] Figure 4 is a flow chart of a method to cool a plurality of electrical components and a traction motor of the vehicle, according to an embodiment of the present disclosure. 25
[0025] The figures depict embodiments of the disclosure for purposes of illustration only. One skilled in the art will readily recognize from the following description that alternative embodiments of the system illustrated herein may be employed without departing from the principles of the disclosure described herein.
DETAILED DESCRIPTION 30
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[0026] While the embodiments in the disclosure are subject to various modifications and alternative forms, specific embodiments thereof have been shown by the way of example in the figures and will be described below. It should be understood, however, that it is not intended to limit the disclosure to the particular forms disclosed, but on the contrary, the disclosure is to cover all modifications, equivalents, and alternatives falling within the scope of the disclosure. 5
[0027] It is to be noted that a person skilled in the art would be motivated by the present disclosure and modify various features of a traction cooling system and a method, without departing from the scope of the disclosure. Therefore, such modifications are considered to be part of the disclosure. Accordingly, the drawings show only those specific details that are pertinent to understand the embodiments of the present disclosure, so as not to obscure the 10 disclosure with details that will be readily apparent to those of ordinary skilled in the art having the benefit of the description herein.
[0028] The terms “comprises”, “comprising”, or any other variations thereof used in the disclosure, are intended to cover non-exclusive inclusions, such that a device, an assembly, a mechanism, a system, and a method that comprises a list of components does not include only 15 those components but may include other components not expressly listed or inherent to such device, or assembly, or mechanism, or system, or method. In other words, one or more elements in a device/assembly/mechanism/system/method proceeded by “comprises… a” does not, without more constraints, preclude the existence of other elements or additional elements in the device or assembly or mechanism or system or method. 20
[0029] In the present disclosure, the term “exemplary” is used herein to mean “serving as an example, instance, or illustration”. Any embodiment or implementation of the present subject matter described herein as “exemplary” is not necessarily to be construed as preferred or advantageous over other embodiments.
[0030] Unless the context of the disclosure describes or indicates a different interpretation, any 25 reference to an object in the specification that is preceded by a definite or indefinite article, such as 'the', 'a', or 'an', should be understood to encompass both the singular and the plural forms of the object. Accordingly, “a” means “at least one/one or more”. The phrase “a/an X” may be construed as “at least one/one or more X”.
[0031] The following paragraphs describe the present disclosure with reference to Figures. 1, 30 2, 3a, 3b, and 4. In the figures, the same element or elements that have similar functions are
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indicated by the same reference signs. With general reference to the drawings, a portion of a vehicle is illustrated and generally identified with reference numeral (200). [0032] Figures 3a and 3b illustrate a portion of the vehicle (200), according to an embodiment of the present disclosure. As an example, the vehicle (200), in accordance with an embodiment of the present disclosure, may be an electric vehicle (EV). However, it will be understood that 5 the teachings of the present disclosure are not limited to any particular vehicle and may be employed in a myriad of categories of vehicles including, but not limited to, hybrid vehicles, internal combustion engine vehicles, passenger vehicles, commercial vehicles, and among others.
[0033] Referring to Figure 1 in conjunction with Figure 3a, the vehicle (200) includes a 10 traction motor (110). The traction motor (110) may include a rotor (not shown in Figures) which is rotatably connected to wheels of the vehicle (200), to propel the vehicle (200) upon operation of the traction motor (110). Further, the vehicle (200) includes a plurality of electrical components (106a, 106b, 108, 112) connected to the traction motor (110). The plurality of electrical components (106a, 106b, 108, 112) comprises at least one DC-DC converter (108), 15 at least one inverter (106a, 106b), and a motor control unit (112). The traction motor (110) and the plurality of electrical components (106a, 106b, 108, 112) form a traction system (114). In an embodiment, the traction motor (110) and the motor control unit (112) may be connected in series with the at least one DC-DC converter (108) and the at least one inverter (106a, 106b). Furthermore, the vehicle (200) includes a power source (not shown in Figures) connected to 20 the plurality of electrical components (106a, 106b, 108, 112) and is configured to supply power to the traction motor (110). The power source may be a High-Voltage (HV) battery unit having a plurality of rechargeable batteries. The at least one inverter (106a, 106b) is configured to convert direct current (DC) power received from the power source to alternate current (AC) power that is required to operate the traction motor (110). Further, the at least one DC-DC 25 converter (108) is configured to convert the high-voltage DC power received from the power source to a low voltage DC power. Furthermore, the motor control unit (112) is configured to regulate the power supplied to the traction motor (110). The motor control unit (112) may vary the supply of power from the power source to the plurality of electrical components (106a, 106b, 108, 112) and the traction motor (110), based on the actuation of at least one control 30 pedal (not shown in Figs.) by a driver of the vehicle (200). In an embodiment, the at least one control pedal may be an accelerator pedal and a brake pedal. In addition, the vehicle (200)
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includes a traction cooling system (100) to cool the traction motor (110) and the plurality of electrical components (106a, 106b, 108, 112) by absorbing the heat generated in the traction motor (110) and the plurality of electrical components (106a, 106b, 108, 112). [0034] As illustrated schematically in Figure 1, the traction cooling system (100) includes a radiator (116) defined with an inlet (116a) and an outlet (116b). The radiator (116) may be 5 mounted on a chassis (202) of the vehicle (200) and may be positioned at a frontal or a rear portion of the vehicle (200) to receive ram air onto the radiator (116) with forced air from at least one cooling fan (118). The radiator (116) is structured to receive the hot coolant, i.e., the coolant with a second predetermined temperature, from the traction system (114), i.e., from the plurality of electrical components (106a, 106b, 108, 112) and the traction motor (110), through 10 the inlet (116a), to cool the coolant to a first predetermined temperature. The radiator (116) includes a radiator housing (not shown in Figures). The radiator housing may include a plurality of tubes (not shown in Figures) parallelly disposed along a height of the radiator housing to allow passage of the coolant. The cooling air exchanges heat with the hot coolant flowing through the plurality of tubes of the radiator (116) to reduce the temperature of the coolant 15 from the second predetermined temperature to the first predetermined temperature. Each tube of the plurality of tubes may be defined with a plurality of fins (not shown in Figures) extending radially or at an angle from the outer surface of the corresponding tube, to improve heat transfer between the hot coolant and the cooling air.
[0035] The traction cooling system (100) further includes a first coolant flow path (102) 20 fluidically connected to the outlet (116b) of the radiator (116) and a traction system (114). The traction system (114) includes the plurality of electrical components (106a, 106b, 108, 112), and the traction motor (110). Furthermore, the traction cooling system includes a pump (104) fluidically disposed in the first coolant flow path (102). The pump (104) is configured to supply the coolant received from the outlet (116b) of the radiator (116) to the first coolant flow path 25 (102), i.e., to the traction system (114), at a first predetermined pressure and at a predetermined flow rate. The coolant may be at least one of a water, a combination of water and a glycol, and among others, which is capable of absorbing the heat from the plurality of electrical components (106a, 106b, 108, 112) and the traction motor (110). The pump (104) is defined with an inlet (104a) and an outlet (104b). The outlet (104b) of the pump (104) is fluidly 30 connected to one of the plurality of electrical components (106a, 106b, 108, 112) in the first coolant flow path (102). The inlet (104a) of the pump (104) receives the coolant at the first
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predetermined temperature from the outlet (116b) of the radiator (116). In an embodiment, the pump (104) may be at least one of a centrifugal pump, an axial pump, a rotary pump, and among others, which is capable of supplying the coolant at the first predetermined pressure to the first coolant flow path (102), i.e., to the traction system (114). [0036] The traction cooling system (100) includes a bypass flow path (120) defined with a first 5 end (120a) and a second end (120b). The first end (120a) is fluidically connected to the outlet (104b) of the pump (104), and the second end (120b) is fluidically connected to the inlet (116a) of the radiator (116). In an embodiment, at least one of the first end (120a) and the second end (120b) of the bypass flow path (120) may be connected at any other locations in the traction system (114), without limiting the scope of the present disclosure. The bypass flow path (120) 10 may be one of: at least one conduit, at least one channel, at least one duct. The bypass flow path (120) is configured to maintain the pressure drop of the coolant at a second predetermined pressure drop across the bypass flow path (120) and the traction system (114) to maintain a predetermined rate of flow of the coolant through the traction system (114). That is, the bypass flow path (120) is structured to create a resistance for the flow of the coolant to generate a 15 pressure drop which is equivalent to the pressure drop caused at the traction system (114) due to the flow of coolant through the traction system (114). In other words, the bypass flow path (120) maintains the coolant across the bypass flow path (120) and in the first coolant flow path (102), i.e., in the traction system (114), at a constant pressure drop, thereby maintaining the constant flowrate through the traction system (114) without any substantial pressure drop. In 20 an embodiment, the bypass flow path (120) may be configured to maintain the pressure drop of the coolant at the second predetermined pressure drop across any one or more components of the traction system (114), i.e., across the plurality of electrical components (106a, 106b, 108, 112) and the traction motor (110). Consequently, the mass flow rate of the coolant flowing through the traction system (114) is improved, even at a low or medium speed of the pump 25 (104).
[0037] Since the constant flow rate through the traction system (114) can be maintained without any substantial pressure drop, the efficiency of the traction motor (110) and the plurality of electrical components (106a, 106b, 108, 112) can be increased. Further, the hot coolant received from the traction system (114) is mixed with the cooled coolant from the 30 bypass flow path (120). This reduces the temperature of the coolant entering the inlet (116a) of the radiator (116), thereby reducing the power required to operate the radiator cooling fan,
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and consequently, increasing the range of EV. Due to the radiator operating with low power, the Noise, Vibration, and Harshness (NVH) generated by the radiator cooling fan are low. Such low NVH increases comfort of the passengers and enhances the life span of the radiator cooling fan. [0038] Referring to Figure 1, in an exemplary embodiment of the present disclosure, the 5 traction system (114) includes two inverters (106a, 106b) arranged parallel to each other in the first coolant flow path (102). Further, the traction system (114) includes one DC-DC converter (108) and the motor control unit (112), arranged in parallel in the first coolant flow path (102). Furthermore, the traction system (114) includes at least two manifolds (125) provided in the first coolant flow path (102). Each manifold (125) may include at least two conduits (125a) 10 connected to each of the two inverters (106a, 106b), the DC-DC converter (108), and the motor control unit (112), to receive the first predetermined volume of the coolant at the first predetermined temperature from the outlet (104b) of the pump (104).
[0039] Now referring to Figure 2 in conjunction with Figure 1, a perspective view of the traction cooling system (100) is depicted. The at least one inverter (106a, 106b) and the at least 15 one DC-DC converter (108) are positioned downstream and proximate to the radiator (116). The traction motor (110) is positioned downstream to the at least one inverter (106a, 106b) and the at least one DC-DC converter (108), and at a distance from the radiator (116). Further, the motor control unit (112) is disposed proximal to the traction motor (110). As depicted in Figure 3a, the pump (104) is mounted below the radiator (116) and the at least one DC-DC converter 20 (108). The pump (104), the at least one inverter (106a, 106b), the at least one DC-DC converter (108), the traction motor (110), and the motor control unit (112) are sequentially disposed in the first coolant flow path (102) in a closed loop configuration.
[0040] In an embodiment, the first coolant flow path (102) may include a plurality of conduits (102a, 102b, 102c) disposed within the traction system (114) and are structured to allow the 25 flow of coolant therewithin. That is, each of the plurality of conduits (102a, 102b, 102c) are branched into further extensions or conduits for connecting with each of the at least one DC-DC converter (108), the at least one inverter (106a, 106b), the motor control unit (112), and the traction motor (110). Referring to Figures 3a and 3b, the traction system (114) may include at least two manifolds (125) having a plurality of set of conduits (128, 130, 132) structured to 30 divide the coolant in the first coolant flow path (102) and supply the coolant through the plurality of electrical components (106a, 106b, 108, 112).
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[0041] The traction cooling system (100) may include a storage tank (124), fluidically connected to the radiator (116). The storage tank (124) may be structured to store and supply the coolant to the first coolant flow path (102), when the volume of the coolant in the first coolant flow path (102) is below a predetermined volume. The storage tank (124) is structured to supply the coolant in an event of leakage or expansion of the coolant in the first coolant flow 5 path (102). The storage tank (124) is defined with a first outlet (124a) and a second outlet (124b). The first outlet (124a) may be connected to the pump (104) through an auxiliary pipe (124c). The second outlet (124b) may be defined opposite to the first outlet (124a) of the storage tank (124) and the second outlet (124b) may be connected to the inlet (116a) of the radiator (116) for supplying the backup coolant to the radiator (116). 10
[0042] Again, referring to Figures 3a and 3b, the pump (104) is connected to the chassis (202) of the vehicle (200). In an embodiment, the pump (104) may be connected to at least one surface of the chassis (202) by at least one bracket (not shown in Figures). The pump (104) may be connected to the at least two manifolds (125) through the first conduit (102a). The plurality of conduits (128, 130, 132) may extend perpendicularly from each of the at least two 15 manifolds (125). The plurality of conduits (128, 130, 132) may include a first set of conduits (128) and a second set of conduits (130) extending from the at least two manifolds (125). The first set of conduits (128) may be connected to the at least one inverter (106a, 106b) and the second set of conduits (130) may be connected to the auxiliary inverter (106b). Each conduit of the first and second set of conduits (128, 130) may act as an inlet and an outlet for the coolant 20 to flow in and out of the inverter (106a) and the auxiliary inverter (106b), respectively. Further, a third set of conduits (132) may be connected to the at least one DC-DC converter (108) to allow the coolant flow into and out of the at least one DC-DC converter (108).
[0043] The at least two manifolds (125) may be further defined with a manifold inlet (125b) and a manifold outlet (125c). The manifold inlet (125b) may be connected to the first conduit 25 (102a) to receive the coolant from the pump (104). The manifold outlet (125c) may be connected to a second conduit (102b). The second conduit (102b) may extend from the manifold outlet (125c) towards the traction motor (110). The second conduit (102b) may be connected to the traction motor (110) to supply the coolant from the manifold outlet (125c) to the traction motor (110). The second conduit (102b) may extend across the traction motor (110) 30 and may connect to the motor control unit (112). The coolant received from the second conduit (102b) may further absorb the heat generated by the traction motor (110) and the motor control
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unit (112) during the operation of the vehicle (200) and dissipates heat to the coolant to the third predetermined temperature. The hot coolant at the third predetermined temperature is then transferred to the radiator (116) through a third conduit (102c). The third conduit (102c) is connected to the inlet (116a) of the radiator (116). The coolant at the third predetermined temperature is mixed with the coolant at the second predetermined temperature received from 5 the bypass flow path (120) and is supplied to the radiator (116). The hot coolant at the second predetermined temperature is passed through the radiator (116) for heat transfer between the hot coolant and the ram air to cool the coolant to the first predetermined temperature. The coolant coming out of the outlet (116b) of the radiator (116) is again transferred to the inlet (104a) of the pump (104) to continue the cooling cycle. 10 [0044] Again, referring to Figures 3a and 3b, the bypass flow path (120) may be defined with a bypass conduit (120c) connected to the inlet (104a) of the pump (104) and the third conduit (102c). The bypass conduit (120c) is structured with a predefined diameter, a predefined length having a predefined internal surface roughness to create the required pressure drop to maintain the coolant at the second predetermined pressure drop. The predefined diameter and the 15 predefined length of the bypass conduit (120c) may be derived by evaluating the pressure drop across the first coolant flow path (102) between the traction system (114), i.e., between the plurality of electrical components (106a, 106b, 108, 112) and the traction motor (110). The pressure drop in the traction system (114) may be compensated or mitigated by the bypass flow path (120) such that the pressure drop of the coolant flowing across the first coolant flow path 20 (102) of the traction system (114) is equal to the pressure drop of the coolant within the bypass flow path (120). This ensures uniform coolant flow along the first coolant flow path (102) with an improved flow rate of the coolant through the radiator (116) to cool the traction system (114). Further, maintaining the constant pressure drop of the coolant at the second predetermined pressure drop across the bypass flow path (120) and the traction system (114) 25 aids in increasing a limiting the ambient temperature of the entire traction cooling system (100), because of increased coolant flow from the radiator, as the heat dissipation capacity increases. Such an increase in limiting ambient temperature enables the vehicle to operate in harsh climatic conditions.
[0045] In an operational embodiment, the motor control unit (112) is configured to determine 30 the ignition ON condition of the vehicle (200). The pump (104) is actuated to discharge the coolant at the first predetermined temperature and at the first predetermined pressure, wherein
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a first predetermined volume of the coolant is discharged to the traction system (114) through the first coolant flow path (102) and a second predetermined volume of the coolant is discharged to the first end (120a) of the bypass flow path (120). The coolant flows through the bypass flow path (120) to maintain the pressure drop of the coolant at the second predetermined pressure drop across the bypass flow path (120) and the traction system (114). The first 5 predetermined volume of the coolant flows through the traction system (114) through the first coolant flow path (102), where the coolant absorbs the heat generated by the traction system (114), i.e., the plurality of electrical components (106a, 106b, 108, 112) and the traction motor (110), and heat the coolant to the third predetermined temperature. The inlet (116a) of the radiator (116) receives hot coolant from the traction system (114) at the third predetermined 10 temperature and is mixed with the coolant received from the bypass flow path (120) having the first predetermined temperature, to cool the coolant to the second predetermined temperature before entering the inlet (116a) of the radiator (116). In other words, the hot coolant received from the traction system (114) is partially cooled by supplying the cooled coolant through the bypass flow path (120). The inlet (116a) of the radiator (116) receives the hot coolant with the 15 second predetermined temperature. The hot coolant at the second predetermined temperature is passed through the radiator (116) for heat transfer between the hot coolant and the ram air to cool the coolant to the first predetermined temperature. The coolant at the first predetermined temperature is received by the inlet (104a) of the pump (104) and the pump (104) discharges the coolant at the first predetermined temperature and at the first predetermined pressure to the 20 bypass flow path (120) and the first coolant flow path (102), i.e., to the traction system (114), and the cycle repeats. [0046] In an embodiment, each of the plurality of electrical components (106a, 106b, 108, 112), and the traction motor (110) comprises a plurality of cooling jackets (not shown in Figures), fluidly connected to the first coolant flow path (102). The plurality of cooling jackets 25 are structured to absorb heat from each of the plurality of electrical components (106a, 106b, 108, 112) and the traction motor (110), and exchange the heat with the coolant in the traction system (114). Further, the traction cooling system (100) may include a control unit. The control unit may be configured to determine an ignition ON condition of the vehicle (200) and actuate the pump (104) to initiate the cooling process of the traction cooling system (100). In addition, 30 the control unit may be configured to turn OFF the pump (104) upon detection of an ignition OFF condition of the vehicle (200) to stop the said cooling process.
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[0047] In another non-limiting embodiment of the present disclosure, a method (300) to cool a plurality of electrical components (106a, 106b, 108, 112) and a traction motor (110) of a vehicle (200) is disclosed. At step (302), the method (300) includes supplying (302) a coolant at a predetermined pressure, by a pump (104), to a first coolant flow path (102). The first coolant flow path (102) is fluidically connected to an outlet (116b) of a radiator (116), the 5 plurality of electrical components (106a, 106b, 108, 112) and the traction motor (110). Further, at step (304) the method (300) includes supplying the coolant, by the pump (104), to a bypass flow path (120). The bypass flow path (120) is defined with a first end (120a) and a second end (120b). The first end (120a) is fluidically connected to the pump (104) and the second end (120b) is fluidically connected to the inlet (116a) of the radiator (116). The bypass flow path 10 (120) is configured to maintain the pressure drop of the coolant at a second predetermined pressure drop across the first coolant flow path (102) and the traction system (114) to maintain a predetermined rate of flow of the coolant through the traction system (114).
[0048] In an embodiment, the traction cooling system (100) of the present disclosure aids in maintaining the constant pressure drop of the coolant at the second predetermined pressure 15 drop across the bypass flow path (120) and the traction system (114), thereby increasing a limiting ambient temperature of the traction cooling system (100). Such an increase in limiting ambient temperature enables the vehicle (200) to operate in harsh climatic conditions. Since the constant pressure drop of the coolant is maintained across the bypass flow path (120) and the traction system (114), a constant flowrate through the traction system (114) can be achieved 20 without any substantial pressure drop, thereby increasing the efficiency of the traction motor (110) and the plurality of electrical components (106a, 106b, 108, 112). Further, the hot coolant received from the traction system (114) is mixed with the cooled coolant from the bypass flow path (120). This reduces the temperature of the coolant entering the inlet (116a) of the radiator (116), thereby reducing the power required to operate the radiator cooling fan, and 25 consequently, increasing the range of EV. Due to the radiator cooling fan operating with low power, the Noise, Vibration, and Harshness (NVH) generated by the radiator cooling fan is low. Such low NVH increases comfort of the passengers and enhances the life span of the radiator cooling fan.
[0049] It is to be understood that a person of ordinary skill in the art may develop a traction 30 cooling system (100) of a similar configuration without deviating from the scope of the present disclosure. Such modifications and variations may be made without departing from the scope of the present invention. Therefore, it is intended that the present disclosure covers such
16
modifications and variations provided they come within the ambit of the appended claims and their equivalents.
COMPARISION TABLE
[0050] The traction cooling system (TCS) (100) of the present disclosure is compared with the conventional/existing cooling system with all the inputs viz. heat loads, the cooling 5 airflow and the temperature, the radiator and the cooling fans remaining the same and the results are summarized in terms of variables in below table:
Table 1
[0051] From the Table 1, it is evident that the limiting ambient temperature is around T1 oC for the existing layout due to lower coolant flow “x” because of the pressure drop generated 10 across the traction motor and the plurality of electrical components such as, the at least one DC-DC Converter, the at least one inverter, and the motor control unit during the operation of the vehicle. Further, the power of the water pump which is required to supply the coolant through the existing cooling system is also high up to P1 watts. However, the traction cooling system (100) of the present disclosure has provided higher coolant flow rate around “2x” which 15 is double or 100% more than the existing traction cooling system. Consequently, this increase in the coolant flow rate further increased the limiting ambient temperature, for example, by 2 oC in vehicle test condition 1, and by 4 oC in vehicle test condition 2, with exceptionally low
Existing
Layout of TCS
TCS of the
present disclosure
Sr. no.
Parameter
Units
Test Condition 1
Test Condition 2
Test Condition 1
Test Condition 2
1
Coolant flow [1d]
lpm
x
x
2x
2x
2
Design ambient
oC
T
T
T
T
3
Limiting Ambient Temperature
[1d simulation] > T
oC
T1
T2
T1 + 2 o C
T2 + 4 o C
4
Water pump speed
rpm
N1
N2 = 0.5 N1
5
water pump power [1d simulation]
W
P1
P2= 0.5 P1
17
requirement of pump capacity which can be achieved only at P2 watt power (half of existing layout pump power requirement) at half the pump speed.
EQUIVALENTS
[0052] With respect to the use of substantially any plural and/or singular terms herein, those having skill in the art can translate from the plural to the singular and/or from the singular to 5 the plural as is appropriate to the context and/or application. The various singular/plural permutations may be expressly set forth herein for sake of clarity.
[0053] In addition, where features or aspects of the disclosure are described in terms of Markush groups, those skilled in the art will recognize that the disclosure is also thereby described in terms of any individual member or subgroup of members of the Markush group. 10
[0054] While various aspects and embodiments have been disclosed herein, other aspects and embodiments will be apparent to those skilled in the art. The various aspects and embodiments disclosed herein are for purposes of illustration and are not intended to be limiting, with the true scope and spirit being indicated by the following claims.
[0055] It will be understood by those within the art that, in general, terms used herein, and 15 especially in the appended claims (e.g., bodies of the appended claims) are generally intended as “open” terms (e.g., the term “including” should be interpreted as “including but not limited to,” the term “having” should be interpreted as “having at least,” the term “includes” should be interpreted as “includes but is not limited to,” etc.). It will be further understood by those within the art that if a specific number of an introduced claim recitation is intended, such an intent 20 will be explicitly recited in the claim, and in the absence of such recitation no such intent is present. For example, as an aid to understanding, the following appended claims may contain usage of the introductory phrases “at least one” and “one or more” to introduce claim recitations. However, the use of such phrases should not be construed to imply that the introduction of a claim recitation by the indefinite articles “a” or “an” limits any particular 25 claim containing such introduced claim recitation to inventions containing only one such recitation, even when the same claim includes the introductory phrases “one or more” or “at least one” and indefinite articles such as “a” or “an” (e.g., “a” and/or “an” should typically be interpreted to mean “at least one” or “one or more”); the same holds true for the use of definite articles used to introduce claim recitations. In addition, even if a specific number of an 30 introduced claim recitation is explicitly recited, those skilled in the art will recognize that such recitation should typically be interpreted to mean at least the recited number (e.g., the bare
18
recitation of “two recitations,” without other modifiers, typically means at least two recitations, or two or more recitations). Furthermore, in those instances where a convention analogous to “at least one of A, B, and C, etc.” is used, in general such a construction is intended in the sense one having skill in the art would understand the convention (e.g., “a system”) having at least one of A, B, and C” would include but not be limited to the system that have A alone, B alone, 5 C alone, A and B together, A and C together, B and C together, and/or A, B, and C together, etc.). In those instances, where a convention analogous to “at least one of A, B, or C, etc.” is used, in general, such a construction is intended in the sense one having skill in the art would understand the convention (e.g., “a system having at least one of A, B, or C” would include but not be limited to system that have A alone, B alone, C alone, A and B together, A and C 10 together, B and C together, and/or A, B, and C together, etc.). It will be further understood by those within the art that virtually any disjunctive word and/or phrase presenting two or more alternative terms, whether in the description, claims, or drawings, should be understood to contemplate the possibilities of including one of the terms, either of the terms, or both terms. For example, the phrase “A or B” will be understood to include the possibilities of “A” or “B” 15 or “A and B.” While various aspects and embodiments have been disclosed herein, other aspects and embodiments will be apparent to those skilled in the art. The various aspects and embodiments disclosed herein are for purposes of illustration and are not intended to be limiting, with the true scope and spirit being indicated by the following claims.
REFERRAL NUMERICALS 20
Part
Numeral
Traction cooling system
100
Vehicle
200
First coolant flow path
102
First conduit
102a
Second conduit
102b
Third conduit
102c
Pump
104
Inlet of the pump
104a
Outlet of the pump
104b
At least one inverter
106a
Auxiliary inverter
106b
19
At least one DC-DC converter
108
Traction motor
110
Motor control unit
112
Traction system
114
Radiator
116
Inlet of the radiator
116a
Outlet of the radiator
116b
At least one cooling fan
118
Bypass flow path
120
First end of the bypass flow path
120a
Second end of the bypass flow path
120b
Bypass conduit
120c
Storage tank
124
First outlet of the storage tank
124a
Second outlet of the storage tank
124b
Auxiliary pipe
124c
At least two manifolds
125
At least two conduits
125a
Manifold inlet
125b
Manifold outlet
125c
First set of conduits
128
Second set of conduits
130
Third set of conduits
132
Vehicle
200
Chassis
202
Method
300
Method step
302, 304
20
We claim:
1. A traction cooling system (100) of a vehicle (200), comprising:
a radiator (116) defined with an inlet (116a) and an outlet (116b);
a first coolant flow path (102) fluidically connected to the outlet (116b) of the radiator (116) and a traction system (114), wherein the traction system (114) comprises 5 a plurality of electrical components (106a, 106b, 108, 112), and a traction motor (110);
a pump (104) fluidically disposed in the first coolant flow path (102) configured to supply coolant at a first predetermined pressure; and
a bypass flow path (120) defined with a first end (120a) and a second end (120b), the first end (120a) is fluidically connected to the pump (104), and the second end 10 (120b) is fluidically connected to the inlet (116a) of the radiator (116), the bypass flow path (120) is configured to maintain the same pressure drop of the coolant at a second predetermined pressure drop across the bypass flow path (120) and the first coolant flow path (102) and traction system (114), to maintain a predetermined rate of flow of the coolant through the traction system (114). 15
2. The traction cooling system (100) as claimed in claim 1, wherein the plurality of electrical components (106a, 106b, 108, 112) comprises at least one DC-DC converter (108), at least one inverter (106a, 106b), and a motor control unit (112).
3. The traction cooling system (100) as claimed in claim 1, wherein the bypass flow path (120) is one of: at least one conduit, at least one channel, and at least one duct. 20
4. The traction cooling system (100) as claimed in claim 1, wherein each of the plurality of electrical components (106a, 106b, 108, 112), and the traction motor (110) comprises a plurality of cooling jackets, fluidly connected to the first coolant flow path (102), wherein the plurality of cooling jackets are structured to absorb heat from each of the plurality of electrical components (106a, 106b, 108, 112) and the traction motor (110), 25 and exchange the heat with the coolant in the traction system (114).
5. The traction cooling system (100) as claimed in claim 1, comprising a storage tank (124), fluidically connected to the radiator (116), and structured to store and supply the coolant to the first coolant flow path (102), when the volume of the coolant in the first coolant flow path (102) is below a predetermined volume. 30
21
6. A vehicle (200), comprising:
a traction system (114) comprising:
a traction motor (110); and
a plurality of electrical components (106a, 106b, 108, 112) connected to the traction motor (110); 5
a power source connected to the plurality of electrical components (106a, 106b, 108, 112); and
a traction cooling system (100), comprising:
a radiator (116) defined with an inlet (116a) and an outlet (116b);
a first coolant flow path (102) fluidically connected to the outlet (116b) of 10 the radiator (116) and the traction system (114);
a pump (104) fluidically disposed in the first coolant flow path (102) configured to supply coolant at a first predetermined pressure; and
a bypass flow path (120) defined with a first end (120a) and a second end (120b), the first end (120a) is fluidically connected to the pump (104), and the 15 second end (120b) is fluidically connected to the inlet (116a) of the radiator (116), the bypass flow path (120) is configured to maintain the pressure drop of the coolant at a second predetermined pressure drop across the bypass flow path (120) and the traction system (114) to maintain a predetermined rate of flow of the coolant through the traction system (114). 20
7. The vehicle (200) as claimed in claim 8, wherein the plurality of electrical components (106a, 106b, 108, 112) comprises at least one DC-DC converter (108), at least one inverter (106a, 106b), and a motor control unit (112).
8. The vehicle (200) as claimed in claim 8, wherein the bypass flow path (120) comprises is one of: at least one conduit, at least one channel, and at least one duct. 25
9. The vehicle (200) as claimed in claim 8, comprising a storage tank (124), fluidically connected to the radiator (116), and structured to store and supply the coolant to the first coolant flow path (102), when the volume of the coolant in the first coolant flow path (102) is below a predetermined volume.
10. A method (300) to cool a plurality of electrical components (106a, 106b, 108, 112) and 30 a traction motor (110) of a vehicle (200), the method (300) comprising:
22
supplying (302) a coolant at a predetermined pressure, by a pump (104), to a first coolant flow path (102), wherein the first coolant flow path (102) is fluidically connected to an outlet (116b) of a radiator (116), the plurality of electrical components (106a, 106b, 108, 112) and the traction motor (110);
supplying (304) the coolant, by the pump (104), to a bypass flow path (120), 5 wherein the bypass flow path (120) is defined with a first end (120a) and a second end (120b), the first end (120a) is fluidically connected to the pump (104), the second end (120b) is fluidically connected to the inlet (116a) of the radiator (116), the bypass flow path (120) is configured to maintain the pressure drop of the coolant at a second predetermined pressure drop across the first coolant flow path (102) and the traction 10 system (114) to maintain a predetermined rate of flow of the coolant through the traction system (114).