FORM 2
THE PATENTS ACT 1970
[39 OF 1970]
&
THE PATENTS RULES, 2003
COMPLETE SPECIFICATION
[See section 10; rule 13] TITLE: “A REFRIGERATION CYCLE APPARATUS”
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 nature of the invention and the manner in which it is to be performed.

TECHNICAL FIELD
[001] Present disclosure generally relates to the field of automobiles. Particularly, but not exclusively, the present disclosure relates to a refrigeration cycle apparatus. Further, embodiments of the present disclosure discloses about the refrigeration cycle apparatus having an oil bypass line for recirculating oil separated from an oil separator back to a compressor.
BACKGROUND OF THE DISCLOSURE
[002] Refrigeration cycle apparatus such as an air conditioning (AC) system includes a compressor, a condenser, an expansion valve and an evaporator which are connected in a sequence, through fluid lines through which a refrigerant flows. Generally, when the refrigerant passes through the compressor, part of the refrigerant gets mixed with a compressor oil. The mixture of refrigerant and the compressor oil flows through the fluid lines and through the components of the refrigeration cycle apparatus to cater cooling effect. During circulation of the mixture of refrigerant and the oil, some portion of the oil gets traps within the fluid lines, inside the condenser, the evaporator and the expansion valve. This leads to reduction in the amount of oil circulated back to the compressor, which causes deficiency of oil in the compressor. Deficiency of oil inside the compressor leads to mechanical failure of the compressor such as damage to the moving parts, damage to bearings, damage to compressor sealing and the like. Further, the oil trapped inside a surface of the condenser and the evaporator, causes reduction in efficiency of the heat exchanging capability of the refrigeration cycle apparatus, thereby affecting efficiency of the refrigeration cycle apparatus.
[003] The present disclosure is directed to overcome one or more limitations stated above or other such limitations associated with the prior art.
SUMMARY OF THE DISCLOSURE
[004] One or more shortcomings of conventional systems are overcome and additional advantages are provided through configuration of a refrigeration cycle apparatus as claimed in the present disclosure. 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 as a part of the claimed disclosure.
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[005] In one non-limiting embodiment of the disclosure, a refrigeration cycle apparatus is disclosed. The apparatus includes a compressor, an oil separator, a condenser, an expansion valve and an evaporator, fluidly coupled to each other. Further, the apparatus includes a first flow path fluidly coupled to the compressor and the oil separator. The first flow path is configured to allow flow of mixture of refrigerant and oil from the compressor to the oil separator. Furthermore, the apparatus includes a second flow path fluidly coupled to the oil separator and a suction side of the compressor. The second flow path is configured to allow flow of the oil from the oil separator into the compressor. Additionally, the apparatus includes a flow control valve fluidly disposed in the second flow path, the flow control valve is configured to selectively allow flow of oil into the compressor. The apparatus further includes a control unit which is communicatively coupled to the flow control valve. The control unit is configured to receive a first signal corresponding to a level of oil in the oil separator, receive a second signal corresponding to suction pressure at the suction side of the compressor and actuate, the flow control valve to allow flow of oil into the compressor, when one of the first signal and the second signal exceeds a threshold limit.
[006] In an embodiment of the disclosure, the control unit is configured to operate the flow control valve, when the first signal corresponds to oil level in the oil separator exceeding 50% of total volume.
[007] In an embodiment of the disclosure, the control unit is configured to operate the flow control valve, when the second signal corresponds to delta suction pressure between successive time interval of the compressor being more than a threshold value.
[008] In an embodiment of the disclosure, the refrigeration cycle apparatus includes a level sensor disposed in the oil separator. The level sensor is configured to generate the first signal corresponding to the oil level in the oil separator.
[009] In an embodiment of the disclosure, the refrigeration cycle apparatus includes a pressure sensor disposed in the second flow path, proximal to the suction side of the compressor. The pressure sensor is configured to generate the second signal corresponding to the suction pressure of the compressor.
[010] In an embodiment of the disclosure, the flow control valve is a solenoid valve.

[011] In an embodiment of the disclosure, the oil separator include a filter unit, the filter unit filters the mixture of oil and refrigerant to separate the oil and the refrigerant.
[012] It is to be understood that the aspects and embodiments of the disclosure described above may be used in any combination with each other. Several of the aspects and embodiments may be combined together to form a further embodiment of the disclosure.
[013] 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 following detailed description.
BRIEF DESCRIPTION OF ACCOMPANYING DRAWINGS
[014] The novel features and characteristic of the disclosure are set forth in the appended claims. The disclosure itself, however, as well as a mode of use, further objectives and advantages thereof, will best be understood by reference to the following detailed description of an embodiment when read in conjunction with the accompanying drawings. One or more embodiments are now described, by way of example only, with reference to the accompanying drawings wherein like reference numerals represent like elements and in which:
[015] Figure. 1 illustrates a refrigerant flow circuit diagram of a refrigeration cycle apparatus, in accordance with an embodiment of the present disclosure.
[016] Figure. 2 illustrates a schematic view of a part of the refrigerant flow circuit depicting a first flow path and a second flow path, in accordance with another embodiment of the present disclosure.
[017] 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 structures and methods illustrated herein may be employed without departing from the principles of the disclosure described herein.

DETAILED DESCRIPTION
[018] While the embodiments in the disclosure are subject to various modifications and alternative forms, specific embodiments thereof have been shown by 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 alternative falling within the scope of the disclosure.
[019] It is to be noted that a person skilled in the art would be motivated from the present disclosure and modify various features of the refrigeration cycle apparatus, 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 disclosure with details that will be readily apparent to those of ordinary skilled in the art having benefit of the description herein. Also, the refrigeration cycle apparatus of the present disclosure may be employed in variety of vehicles of different configurations.
[020] The terms “comprises”, “comprising”, or any other variations thereof used in the disclosure, are intended to cover a non-exclusive inclusion, such that the steering assembly and the mechanism that comprises a list of components does not include only those components but may include other components not expressly listed or inherent to such system, method, or assembly, or device. In other words, one or more elements in a system or device proceeded by “comprises… a” does not, without more constraints, preclude the existence of other elements or additional elements in the system or device.
[021] Reference will now be made to the exemplary embodiments of the disclosure, as illustrated in the accompanying drawings. Wherever possible, same numerals will be used to refer to the same or like parts. Embodiments of the disclosure are described in the following paragraphs with reference to Figures. 1 and 2, the same element or elements which have same functions are indicated by the same reference signs.
[022] Figure. 1 illustrates a refrigerant flow circuit (100) diagram of a refrigeration cycle apparatus. In an example, the refrigeration cycle apparatus may be but not limiting to an air conditioner. The refrigeration cycle apparatus may broadly include a compressor (101), a
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condenser (102), an expansion valve (103) and an evaporator (104) which are fluidly coupled to each other in a sequence through fluid lines, which allows flow of refrigerant through these components sequentially. The compressor (101) may be configured to compress and discharge the refrigerant. Refrigerant discharged out of the compressor (101) may possess high temperature and high pressure. The condenser (102) may be configured to exchange heat between the compressed refrigerant and the outdoor air to liquify the refrigerant. In an embodiment, the condenser (102) may be provided with a condenser (102) fan that causes outdoor air to flow over the condenser (102) for exchanging heat. The expansion valve (103) may be configured to adjust the flow of refrigerant from the condenser (102) by changing the opening degree thereof, adjust the pressure of the refrigerant. The evaporator (104) may be configured to exchange heat between air and refrigerant having low pressure.
[023] Referring further to Figure. 2 in tandem with Figure. 1, the refrigeration cycle apparatus may include an oil separator (107) which may be fluidly coupled to the compressor (101) and the condenser (102). The oil separator (107) may receive mixture of oil and refrigerant from the compressor (101) and separate the oil and the refrigerant. The oil separated may be expelled from the oil separator (107) into the compressor (101) and separated refrigerant may be expelled into the condenser (102). In an embodiment, oil separator (107) comprises a filter unit (112). The filter unit (112) may filter the mixture of oil and refrigerant to separate the oil and the refrigerant. In an embodiment, the refrigeration cycle apparatus may include a level sensor which may be disposed in the oil separator (107). The level sensor may be configured to generate a first signal corresponding to an oil level in the oil separator (107).
[024] As apparent from Figure. 2, in an embodiment, the refrigeration cycle apparatus may include a first flow path (105) which may be fluidly coupled to the compressor (101) and the oil separator (107). In other words, the first flow path (105) may extend between the compressor (101) and the oil separator (107) there by fluidly coupling the compressor (101) and the oil separator (107). The first flow path (105) may be configured to allow flow of mixture of refrigerant and oil from the compressor (101) to the oil separator (107). Further the refrigeration cycle apparatus may include a second flow path (106) which may be fluidly coupled to the oil separator (107) and a suction side of the compressor (101). In other words, the second flow path (106) may extend between the oil separator (107) and the suction side of the compressor (101) thereby fluidly coupling the oil separator (107) and the suction side

of the compressor (101). In an embodiment, the refrigeration cycle apparatus may include a pressure sensor (110) which may be disposed in the second flow path (106), proximal to the suction side of the compressor (101). The pressure sensor (110) may be configured to generate a second signal corresponding to a pressure of the compressor (101) at its suction side. In an embodiment, pressure at suction side undergoes less fluctuation and thereby generating the second signal corresponding to the suction side pressure aids in effectively determining deficiency of oil in compressor (101).
[025] Referring further to Figure. 2, refrigeration cycle apparatus may include a flow control valve (108) which may be fluidly disposed in the second flow path (106). The flow control valve (108) may be configured to selectively allow flow of oil into the compressor (101). That is, the flow control valve (108) may allow flow of oil which is separated from the mixture of oil and refrigerant from the oil separator (107) into the compressor (101). As an example, the flow control valve (108) may be but not limiting to a solenoid valve. Further, the refrigeration cycle apparatus may include a control unit (109) which may be communicatively coupled to the flow control valve (108). The control unit (109) may be configured to receive the first signal and the second signal from the flow level sensor (111) and the pressure sensor (110), respectively, and actuate the flow control valve (108) to allow flow of oil into the compressor (101), when one of the first signal and the second signal exceeds a threshold limit. In an embodiment, the threshold limit of the first signal may correspond to oil level in the oil separator exceeding 50% of total volume and threshold limit of the second signal may correspond to delta suction pressure between successive time interval of the compressor (101) being more than a threshold value.
[026] In an operational embodiment, the gaseous refrigerant may pass through a compressor (101), where the gaseous refrigerant may be compressed to high temperature and high pressure. The refrigerant passing through the compressor (101) may get mixed with oil present in the compressor (101) thereby making a mixture of refrigerant and oil. The mixture of refrigerant and oil may then pass into an oil separator (107), through the first flow path (105), where the oil and refrigerant get separated from each other. The separated refrigerant may be then pass into the condenser (102), the expansion valve (103), the evaporator (104) and then back into the compressor (101), in order to cater cooling effect. In an embodiment, refrigerant may be subjected to heat dissipation through heat exchange with an outside air and then condensed.

[027] Once the mixture of oil and refrigerant get separated in the oil separator (107), the flow level sensor (111) in the oil separator (107) may generate the first signal corresponding to the level of oil in the oil separator (107). The first signal may be received by the control unit (109), which analyses the first signal to determine whether the first signal exceeds a threshold limit. If the first signal exceeds the threshold limit, it is an indication that the compressor (101) is deficient with oil and the control unit (109) may actuate the flow control valve (108) to allow flow of oil into the compressor (101). Actuating the flow control valve (108) based on the first signal exceeding the threshold limit ensures maintaining optimum level of oil in the compressor (101). Further, if the control unit (109) determines that the first signal is within the threshold limit, the control unit (109) may receive the second signal from the pressure sensor (110) corresponding to pressure at a suction side of the compressor (101). The control unit (109) may analyse the second signal to determine whether the second signal exceeds the threshold limit. If the second signal exceeds the threshold limit, it is an indication that the compressor (101) is deficient with oil and the control unit (109) may actuate the flow control valve (108) to allow flow of oil into the compressor (101).
[028] The configuration of the refrigeration cycle apparatus of the present disclosure, ensures maintaining optimum quantity of oil in the compressor (101), thereby increases service life of the compressor (101).
[029] It is to be understood that a person of ordinary skill in the art may develop the refrigeration cycle apparatus of 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 modifications and variations provided they come within the ambit of the appended claims and their equivalents.
[030] Equivalents:
[031] 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 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.

[032] It will be understood by those within the art that, in general, terms used herein, and 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 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 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 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 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 systems that have A alone, B alone, 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 systems that have A alone, B alone, C alone, A and B together, A and C 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
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“A” or “B” 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 Numerals:

Component Reference numeral
Refrigerant circuit 100
Compressor 101
Condenser 102
Expansion valve 103
Evaporator 104
First flow path 105
Second flow path 106
Oil separator 107
Flow control valve 108
Control unit 109
Pressure sensor 110
Flow level sensor 111
Filter 112

We Claim:
1. A refrigeration cycle apparatus, the apparatus comprising:
a compressor (101), an oil separator (107), a condenser (102), an expansion valve (103) and an evaporator (104), fluidly coupled to each other;
a first flow path (105) fluidly coupled to the compressor (101) and the oil separator (107), wherein the first flow path (105) is configured to allow flow of mixture of refrigerant and oil from the compressor (101) to the oil separator (107);
a second flow path (106) fluidly coupled to the oil separator (107) and a suction side of the compressor (101), wherein the second flow path (106) is configured to allow flow of the oil from the oil separator (107) into the compressor (101);
a flow control valve (108) fluidly disposed in the second flow path (106), the flow control valve (108) is configured to selectively allow flow of oil into the compressor (101); and
a control unit (109) communicatively coupled to the flow control valve (108), the control unit (109) configured to:
receive, a first signal corresponding to a level of oil in the oil separator (107);
receive, a second signal corresponding to suction pressure at the suction side of the compressor (101); and
actuate, the flow control valve (108) to allow flow of oil into the compressor (101), when one of the first signal and the second signal exceeds a threshold limit.
2. The apparatus as claimed in claim 1, wherein the control unit (109) is configured to operate the flow control valve (108), when the first signal corresponds to oil level in the oil separator exceeding 50% of total volume.
3. The apparatus as claimed in claim 1, wherein the control unit (109) is configured to operate the flow control valve (108), when the second signal corresponds to delta suction pressure between successive time interval of the compressor (101) being more than a threshold value.
4. The apparatus as claimed in claim 1, comprising a level sensor disposed in the oil separator (107), the level sensor is configured to generate the first signal corresponding to the oil level in the oil separator (107).

5. The apparatus as claimed in claim 1, comprising a pressure sensor (110) disposed in the second flow path (106), proximal to the suction side of the compressor (101), wherein the pressure sensor (110) is configured to generate the second signal corresponding to the suction pressure of the compressor (101).
6. The apparatus as claimed in claim 1, wherein the flow control valve (108) is a solenoid valve.
7. The apparatus as claimed in claim 1, wherein the oil separator (107) comprises a filter unit (112), the filter unit (112) filters the mixture of oil and refrigerant to separate the oil and the refrigerant.
8. A vehicle comprising refrigeration cycle apparatus, as claimed in claim 1.