FORM 2
THE PATENT ACT 1970 (as amended)
[39 OF 1970]
&
The Patents Rules, 2003
COMPLETE SPECIFICATION
[See Section 10 and rule 13]
TITLE: “TEMPERATURE CONTROLLED BYPASS VALVE”
Name and address of the Applicant:
TATA MOTORS LIMITED, an Indian company having its registered office at
Bombay House, 24 Homi Mody Street, Hutatma Chowk, Mumbai 400 001, Maharashtra,
INDIA.
Nationality: INDIAN
The following specification particularly describes the invention the manner in which it is to be performed.

TECHNICAL FIELD
Embodiments of the present disclosure relates to a bypass valve, more particularly embodiments relates to temperature controlled bypass valve and a gearbox oil cooling system associated with the temperature controlled bypass valve.
BACKGROUND OF DISCLOSURE
Generally bypass valves are fitted in fluid flow lines to bypass the fluid flowing in the fluid flow line to the fluid medium when pressure in the fluid flow line exceeds the preset pressure or when the fluid flow is not required or intermittent flow is required. The bypass valves can be operated manually, based on pressure or based on temperature.
Gearboxes used in current heavy commercial vehicles carry huge amount of torque. Due to high torque and speeds, the gearbox lubricating oil gets heated up. This temperature may go up to 120 ~ 140º C, if not controlled. To facilitate the cooling of the lubricating oil, these vehicle gearboxes are designed often with an integrated oil circulating pump as shown in FIG. 1. The pump is either coupled with any of the counter shaft gears, idler gear or shaft end itself. The pump supplies oil to the oil cooler which is usually located remote place from the gearbox. The oil cooler receives hot gearbox oil from supply tubing and cools it by dissipating heat to the atmosphere. Then, the cooled oil delivered back to the gearbox through return tubing. The oil pump starts running as soon as the gearbox and engine are coupled (i.e. clutch is engaged). At this point of time the gearbox oil starts getting circulated through the oil cooler even at low oil temperatures, which results in more power consumption from the engine. Therefore, efficiency of the engine reduces.
Further, if gearbox oil is cold, such as at start-up conditions, the oil will be viscous and does not flow easily through the cooler. In such cases, the transmission can be starved of oil and this may cause damage or at the least erratic performance. Cumulative damage to the transmission can also occur if the quantity of oil returned is adequate, but is overcooled due to low ambient temperatures.

In light of foregoing discussion, it is necessary to provide a temperature controlled bypass valve in gearbox oil flow line to bypass the oil to the gear box at low temperatures and to supply the oil to the cooler at high temperatures to overcome the problems stated above.
SUMMARY OF THE DISCLOSURE
The shortcomings of the prior art are overcome and additional advantages are provided through the provision of system and method 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 a part of the claimed disclosure.
One aspect of the present disclosure relates to a temperature controlled bypass valve. The bypass valve comprises a valve body having a fluid inlet port and fluid outlet port. A metal diaphragm of predetermined shape placed in bottom end of the valve body expands and contracts when volatile fluid filled in the metal diaphragm vaporizes upon change in temperature of fluid to be bypassed. A spool with a first spool end and second spool end placed perpendicularly to the metal diaphragm inside the valve body for performing atleast one of, opening the fluid inlet and fluid outlet ports of the valve body to bypass the fluid when the metal diaphragm contacts; and closing the fluid inlet and fluid outlet ports of the valve body to restrict the flow of fluid through the ports when the metal diaphragm expands. The bypass valve further comprises a spring located in between the second spool end and a top end of the valve body, said spring configured to push the spool to original position when the metal diaphragm contracts.
In one aspect of the present disclosure, the top end of the valve body is sealed and bottom end of the valve body is open.
In one aspect of the present disclosure, metal diaphragm is held inside the valve body by at least one circlip and at least one O-ring such that said metal diaphragm makes contact with fluid to be bypassed.

Another aspect of the present disclosure provides a gearbox oil cooling system for a vehicle. The gear box oil cooling system comprises an oil pump in fluid communication with the gearbox, coupled to at least one gear of the gear box, wherein outlet of the oil pump is split into two. A temperature controlled bypass valve mounted on the gearbox fluidly connected to first outlet of the oil pump for bypassing the oil supplied by the oil pump to the gearbox when temperature of the gearbox oil is less than preset temperature value. The bypass valve comprises, a valve body having an oil inlet port and oil outlet port, a metal diaphragm of predetermined shape placed in bottom end of the valve body expands and contracts when volatile fluid filled in the metal diaphragm vaporizes upon change in temperature of gearbox oil, a spool with a first spool end and second spool end placed perpendicularly to the metal diaphragm inside the valve body for performing atleast one of opening the fluid inlet and fluid outlet ports of the valve body to bypass the fluid when the metal diaphragm contracts; and closing the fluid inlet and fluid outlet ports of the valve body to restrict the flow of fluid through the ports when the metal diaphragm expands; and a spring located in between the second spool end and a top end of the valve body, said spring configured to push the spool to original position when the metal diaphragm contracts. The gearbox oil cooler further comprises an oil cooler fluidly connected in between second outlet of the oil pump and the gearbox to cool the gearbox oil when temperature of the gearbox oil exceeds the preset value of temperature, and to supply the cooled oil to the gearbox.
In one aspect of the present disclosure, a T- connector is provided at the outlet of oil pump for supplying oil to the temperature controlled bypass valve and oil cooler.
In one aspect of the present disclosure, the temperature controlled bypass valve is mounted on reverse idler gear window plate of the gear box.
Another embodiment of the present disclosure relates to a method of controlling temperature of gearbox oil. The method comprising, performing an operation selected from at least one of: bypassing oil supplied by the oil pump to the gearbox when temperature of the gearbox oil is less than preset value of temperature using a temperature controlled bypass valve, wherein said temperature controlled bypass valve

operates a spool to open oil inlet and oil outlet ports for bypassing the oil. And passing the oil supplied by the oil pump to the oil cooler for cooling the gearbox oil when temperature of the gearbox exceeds the preset value, wherein temperature controlled bypass valve operates the spool to close oil inlet and oil outlet ports for passing oil to the oil cooler.
In one aspect of the present disclosure, the spool is operated by expansion and contraction of a metal diaphragm of the temperature controlled bypass valve.
In one aspect of the present disclosure, expanding the metal diaphragm to close the ports when temperature of the gearbox oil exceeds the preset value of temperature.
In one aspect of the present disclosure, pushing the spool to open the ports when the metal diaphragm contracts using a spring, to bypass the oil to the gearbox when temperature of the gearbox oil exceeds the preset value of temperature.
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.
OBJECTIVES OF THE DISCLOSURE
One object of the present disclosure is to provide a temperature controlled by pass valve which operates based on the temperature of the fluid to be bypassed.
One object of the present disclosure is to provide a temperature controlled by pass valve comprising a metal bellow filled with volatile fluid which expands and contracts based on temperature of the fluid to be bypassed to open and close the bypass valve.
One object of the present disclosure is to provide a gearbox oil cooling system associated with temperature controlled bypass valve which operate based on the temperature of gearbox oil.

One object of the present disclosure is to provide a gearbox oil cooling system associated with temperature controlled bypass valve which bypass the oil from oil pump to gearbox when temperature of the oil is less than preset value.
One object of the present disclosure is to provide a gearbox oil cooling system associated with temperature controlled bypass valve which close the bypass to supply the oil from oil pump to oil cooler when temperature of the oil is more than preset value.
BRIEF DESCRIPTION OF THE ACCOMPANYING FIGURES
The novel features and characteristic of the disclosure are set forth in the appended claims. 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 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:
FIG. 1 illustrates conventional gear box oil cooling system.
FIG. 2a and 2b illustrates sectional views of a temperature controlled bypass valve in open and closed condition respectively.
FIG. 3a illustrates gearbox oil cooling system associated with temperature controlled bypass valve of the present disclosure in open condition.
FIG. 3b illustrates gearbox oil cooling system associated with temperature controlled bypass valve of the present disclosure in closed condition.
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
The foregoing has broadly outlined the features and technical advantages of the present disclosure in order that the detailed description of the disclosure that follows may be better understood. Additional features and advantages of the disclosure will be described hereinafter which form the subject of the claims of the disclosure. It should be appreciated by those skilled in the art that the conception and specific embodiment disclosed may be readily utilized as a basis for modifying or designing other structures for carrying out the same purposes of the present disclosure. It should also be realized by those skilled in the art that such equivalent constructions do not depart from the spirit and scope of the disclosure as set forth in the appended claims. The novel features which are believed to be characteristic of the disclosure, both as to its organization and method of operation, together with further objects and advantages will be better understood from the following description when considered in connection with the accompanying figures. It is to be expressly understood, however, that each of the figures is provided for the purpose of illustration and description only and is not intended as a definition of the limits of the present disclosure.
To overcome the drawbacks mentioned in the background the gearbox oil cooling system associated with temperature controlled bypass valve which bypass the oil from oil pump to the gear box at low temperatures and supplies oil from oil pump to the oil cooler at high temperatures by opening and closing the bypass valve respectively.
FIGS. 2a and 2b illustrates sectional views of a temperature controlled bypass valve (100) in open and closed condition respectively. The temperature controlled bypass valve (100) comprises a valve body (101) of predetermined shape having an open bottom end (101a) and sealed top end (101b). A fluid inlet port (102) and fluid outlet port (103) is provided in the valve body (101) perpendicular to the axis of the valve body (101) to bypass the fluid. A metal diaphragm (104) of predetermined shape is placed in the bottom end (101a) of the valve body (101) to operate a spool (104) of the bypass valve (100). The metal diaphragm (104) is filled with the volatile fluid and said volatile fluid vaporizes and condenses upon change in temperature of the fluid to be bypassed. In one aspect of

the present disclosure, the metal diaphragm (104) is placed inside the valve body (101) using atleast one circlip and O-ring. The spool (105) with first spool end (105a) and second spool end (105b) is disposed axially inside the valve body (101) for opening and closing the fluid inlet (102) and fluid outlet (103) of the bypass valve (100). The first spool end (105a) makes contact with the metal diaphragm (104) such that the first spool end (105a) is perpendicular to the metal diaphragm (104). The spool (105) opens the fluid inlet (102) and fluid outlet (103) ports of the valve body (101) to bypass the fluid when the metal diaphragm (104) contracts. And closes the fluid inlet (102) and fluid outlet (103) ports of the valve body (101) to restrict the flow of fluid through the ports (102 and 103) when the metal diaphragm (104) expands. The temperature controlled bypass valve (100) further comprises a spring located between second spool end (105b) and the sealed top end (101b) of the valve body to push the spool (105) to its original position when the metal diaphragm (104) contracts.
The metal diaphragm (104) makes contact with the fluid to be bypassed and when the temperature of fluid to be bypassed exceeds the preset temperature value the volatile liquid filled inside the metal diaphragm (104) becomes vapor and results in expansion of the metal diaphragm (104). The metal diaphragm (104) when expanded pushes the spool (105) to close the inlet port (102) and outlet port (103) of the valve body (101) to restrict the bypassing of the oil. When the temperature of fluid to be bypassed falls below the preset value then the volatile fluid filled inside the metal diaphragm (104) condenses and results in contraction of the metal diaphragm (104). When metal diaphragm (104) contracts, the spring (106) pushes the spool (105) to its original position to open the inlet port (102) and outlet port (103) of the valve body (101) to bypass the fluid. The volatile fluid filled inside the metal diaphragm (104) is selected from atleast one of methanol the volumetric coefficient of expansion for this is 0.00118 per ºC i.e. 0.00066 per ºF or it can be solid also which expands on heating.
In one aspect of the present disclosure, the spring (106) is compression coil spring, and said spring (106) is preloaded to apply force on the spool (105) for pushing the spool to open the inlet and outlet ports (102 and 103) of the bypass valve (100). The preload on the spring (106) can be varied to adopt the bypass valve (100) for different applications.

Fig. 3a and 3b are exemplary embodiments illustrating gearbox oil cooling system (300) associated with temperature controlled bypass valve (100) of the present disclosure in open condition and closed condition respectively. The gear box oil cooling system (300) comprises an oil pump (301) in fluid communication with the gearbox (302). The oil pump is coupled to at least one gear (302a) such as counter shaft gear, idler gear or shaft end itself of the gear box (302) for receiving the rotary motion from the engine to pump the oil. The oil pump (301) start operating as soon as the gear coupled (clutch is engaged). An outlet (303) of the oil pump (302) is split into two (303a and 303b) by fitting a connector having one inlet and two outlets such as T-connecter at the outlet (303). The first outlet (303a) of the T-connector is connected to the temperature controlled bypass valve (100) mounted on the gearbox (302) of a vehicle. The temperature controlled bypass valve (100) comprises the components as explained in description of FIGS. 2a and 2b for bypassing the oil supplied by the oil pump (301) to the gearbox (302) when temperature of the gearbox oil is less than preset temperature value. The gearbox oil cooling system (300) further comprises an oil cooler (304) fluidly connected in between second outlet (303b) of the T-connector and the gearbox (302) to cool the gearbox oil when temperature of the gearbox (302) oil exceeds the preset value of temperature, and to supply the cooled oil to the gearbox (302).
The bypass valve (100) is mounted on rear window cover of the gearbox (302) and metal diaphragm (104) bypass valve (100) makes contact with the gearbox oil. The metal diaphragm is held by atleast one circlip and o-ring to make oil proof joint. When the gear box oil temperature exceeds preset value, volatile fluid inside the metal diaphragm vaporizes and expands the metal diaphragm (105). The metal diaphragm (104) when expanded push the spool (105) to close the inlet port (102) and outlet port (103) of the valve body (101) to restrict the bypassing of the oil. Due to which the oil flows to the oil cooler (304) which is fluidly connected in between the second outlet (303a) of the T-connector and the gear box (302). The oil cooler (304) comprises plurality of fins on its surface to dissipate the heat contained in the gearbox oil to cool the gearbox oil. The cooled oil is supplied back to the gearbox (302).

When the gear box oil temperature is less than the preset value the volatile fluid filled inside the metal diaphragm (104) condenses and results in contraction of the metal diaphragm (104). When metal diaphragm (104) contracts, the spring (106) pushes the spool (105) to its original position to open the inlet port (102) and outlet port (103) of the valve body (101) to bypass of the gear box oil. The oil pumped by the oil pump (301) is bypassed to the gearbox (302) at least resistance when temperature of the oil is less.
The preset values of gear box oil temperature varies from vehicle to vehicle and preferably the temperature value should be maintained in range about 60oc to the 80oc. If the gearbox oil temperature exceeds 60oc then the volatile fluid inside the metal diaphragm starts vaporizing and expands the metal diaphragm (105). The metal diaphragm (104) when expanded push the spool (105) to close the inlet port (102) and outlet port (103) of the valve body (101) to restrict the bypassing of the oil. The oil is supplied to the oil cooler (304) to cool the oil and cooled oil is supplied back to the gearbox (302).
The bypassing of gearbox oil to the gearbox at lower temperatures reduces the power consumption since the gearbox oil will be more viscous at lower temperatures. As the temperature increases viscosity of the oil decreases and hence the oil pump (301) consumes less power to pump the oil from gearbox (302) to the oil cooler (304). With the bypass mechanism of the present disclosure the idle running of the oil pump (301) is reduced greatly and results in improvements in the overall efficiency.
Advantages:
The present disclosure provides a temperature controlled by pass valve which operates
based on the temperature of the fluid to be bypassed.
The present disclosure provides the temperature controlled by pass valve comprising a metal bellow filled with volatile fluid which expands and contracts based on temperature of the fluid to be bypassed to open and close the bypass valve.

The present disclosure provides a gearbox oil cooling system associated with temperature controlled bypass valve which operate based on the temperature of gearbox oil, and said bypass valve bypasses the oil from oil pump to gearbox when temperature of the oil is less than preset value and close the bypass to supply the oil from oil pump to oil cooler when temperature of the oil is more than preset value. Hence, prevents idle running of the oil pump and consumes less energy from the engine. Which in-turn improves the engine efficiency.
Equivalents
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.
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 "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;

Reference Number Description
100 Temperature controlled bypass valve
101 Valve body
101a and 101b Top and bottom end of the

valve body
102 Inlet port
103 Outlet port
104 Metal diaphragm
105 Spool
105a and 105b First and second spool end
106 Spring
300 Gearbox oil cooling system
301 Oil pump
302 Gearbox
303 Oil pump outlet
303a and 303b First and second outlet of the oil pump
304 Oil cooler

We claim
1. A temperature controlled bypass valve (100) for gearbox comprising:
a valve body (101) having a fluid inlet port (102) and fluid outlet port (103);
a metal diaphragm (104) of predetermined shape placed in bottom end (101a) of the valve body (101) and in contact with the gearbox oil expands and contracts when volatile fluid filled in the metal diaphragm (104) expand upon change in temperature of the gearbox oil;
a spool (105) with a first spool end (105a) and second spool end (105b) placed perpendicularly to the metal diaphragm (104) inside the valve body (101) for performing atleast one of
opening the fluid inlet (102) and fluid outlet (103) ports of the
valve body (101) to bypass the fluid when the metal diaphragm (104)
contacts; and
closing the fluid inlet and fluid outlet ports (102 and 103) of the
valve body (101) to restrict the flow of fluid through the ports (102 and
103) when the metal diaphragm (104) expands;
a spring (106) located in between the second spool end (105b) and a top end (101b) of the valve body (101), said spring configured to push the spool (105) to original position when the metal diaphragm (104) contacts.
2. The bypass valve as claimed in claim 1, wherein the top end (101b) of the valve body (101) is sealed and bottom end (101a) of the valve body (101) is open.
3. The bypass valve as claimed in claim 1, wherein metal diaphragm (104) is held inside the valve body (101) by at least one circlip and at least one O-ring such that said metal diaphragm (104) makes contact with fluid to be bypassed.
4. A gearbox oil cooling system (300) for a vehicle comprising:
an oil pump (301) in fluid communication with the gearbox (302), coupled to at least one gear (302a) of the gear box (302), wherein outlet (303) of the oil pump (302) is split into two (303a and 303b);

a temperature controlled bypass valve (100) mounted on the gearbox (302) fluidly connected to first outlet (303a) of the oil pump (301) for bypassing the oil supplied by the oil pump (301) to the gearbox (302) when temperature of the gearbox oil is less than preset temperature value, said bypass valve (100) comprises;
a valve body (101) having an oil inlet port (102) and oil outlet port (103);
a metal diaphragm (104) of predetermined shape placed in bottom end (101a) of the valve body (101) and in contact with the gearbox oil expands and contracts when volatile fluid filled in the metal diaphragm (104) vaporizes upon change in temperature of gearbox oil;
a spool (105) with a first spool end (105a) and second spool end (105b) placed perpendicularly to the metal diaphragm (104) inside the valve body (101) for performing atleast one of
opening the fluid inlet (102) and fluid outlet (103) ports of the valve body (101) to bypass the fluid when the metal diaphragm (104) contracts; and
closing the fluid inlet and fluid outlet ports (102 and 103)
of the valve body (101) to restrict the flow of fluid through the
ports (102 and 103) when the metal diaphragm (104) expands; and
a spring (106) located in between the second spool end (105b) and
a top end (101b) of the valve body (101), said spring configured to push
the spool (105) to original position when the metal diaphragm (104)
contacts;
an oil cooler (304) fluidly connected in between second outlet (303b) of the oil pump (301) and the gearbox (302) to cool the gearbox oil when temperature of the gearbox (302) oil exceeds the preset value of temperature, and to supply the cooled oil to the gearbox (302).

5. The system as claimed in claim 4, wherein a T- connector is provided at the outlet (303) of oil pump (301) for supplying oil to the temperature controlled bypass valve (100) and oil cooler (304).
6. The system as claimed in claim 4, wherein the temperature controlled bypass valve (100) is mounted on reverse idler gear window plate (305) of the gear box (302).
7. The system as claimed in claim 1, wherein the preset value of temperature ranges from 600c to 800c.
8. A method of controlling temperature of a gearbox oil, said method comprising the steps of:
performing an operation selected from at least one of:
bypassing oil supplied by the oil pump (301) to the gearbox (302) when temperature of the gearbox oil is less than preset value of temperature using a temperature controlled bypass valve (100), wherein said temperature controlled bypass valve (100) operates a spool (105) to open oil inlet and oil outlet ports (105a and 105b) for bypassing the oil; and
passing the oil supplied by the oil pump (301) to the oil cooler (204) for cooling the gearbox oil when temperature of the gearbox exceeds the preset value, wherein temperature controlled bypass valve (100) operates the spool (105) to close oil inlet and oil outlet ports (105a and 105b) for passing oil to the oil cooler.
9. The method as claimed in claim 8, wherein the spool (105) is operated by
expansion and contraction of a metal diaphragm (104) filled with volatile fluid of
the temperature controlled bypass valve (100).

10. The method as claimed in claim 8, wherein expanding the metal diaphragm (104) to close the ports (102 and 103) when temperature of the gearbox oil exceeds the preset value of temperature.
11. The method as claimed in claim 6, wherein pushing the spool (105) to open the ports (102 and 103) when the metal diaphragm contracts using a spring (106), to bypass the oil to the gearbox when temperature of the gearbox oil exceeds the preset value of temperature.