FORM 2
THE PATENTS ACT, 1970
(39 of 1970)
&
THE PATENTS RULES, 2003
COMPLETE SPECIFICATION
[See section 10, rule 13]
TITLE OF THE INVENTION
“A SYSTEM AND METHOD TO DETECT CLUTCH FAILURE AND DISENGAGE THE
CLUTCH IN SUCH SITUATION”
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.
INVENTOR
MR. ATUL MADHUKARRAO KAJALKAR
An Indian National of
TATA MOTORS LIMITED
Bombay House, 24 Homi Mody Street,
Hutatma Chowk, Mumbai 400 001,
Maharashtra, INDIA.
PREAMBLE TO THE DESCRIPTION
The following specification particularly describes the invention and the manner
in which it is to be performed

TECHNICAL FIELD
The present invention generally relates to automotive vehicle and more particularly it relates to a clutch system for vehicles.
Definition:
“No Fault state” - is a state in which the slave cylinder is functioning properly in absence of internal external leakages, accordingly the slave cylinder is capable to develop the required hydraulic pressure to operate the clutch release lever to disengage the clutch;
"Fault state"– is a state arising due to malfunction of “slave cylinder”, due to internal / external leakages in cylinder or hoses or for any other reason, wherein the slave cylinder (3) is incapable to develop the required hydraulic pressure to operate the clutch release lever to disengage the clutch;
BACKGROUND OF THE INVENTION
A failure of clutch actuation system in vehicle running condition creates most unsafe situation for vehicle user.
If clutch actuation system fails (malfunction of clutch slave cylinder) in vehicle running condition, then vehicle user will not be able to change gears. This is because the clutch will not get disengaged and engine power cannot be cut off. If vehicle user has to safely take the vehicle to side or halt, then only braking option will be at disposal with the driver. If vehicle is already in high gear with considerable speed, this option will also not work. If user forcefully tries to change the gear or brakes harshly, then there is every possibility of damage to transmission/engine components which will render the vehicle in break-down condition. This poses a grave safety and life threatening risk to the vehicle occupants.
Accordingly, there is a need for a clutch fault detection and clutch assist system that not detects "Fault state" in clutch slave cylinder during manual clutch operation of the clutch but also assists in disengaging the clutch in such situation, thereby avoiding the dangerous situations arising due to "Fault state" of the slave cylinder.
OBJECTS OF THE INVENTION
The object of the present disclosure is to provide a clutch fault detection and clutch assist system that obviates the drawbacks of the conventional clutch system;

Another object of the present invention is to provide a clutch fault detection and clutch assist
system that not only detects "Fault state" in clutch slave cylinder during manual clutch
operation of the clutch but also assists in disengaging the clutch in such condition, thereby
avoiding the dangerous situations arising due to "Fault state" of the slave cylinder;
Still another object of the present invention is to provide a clutch fault detection and clutch
assist system that alerts the driver incase "Fault state" in clutch slave cylinder is detected
through audible alert signal, thereby prompting the driver to take necessary precautions such
as approaching the nearest service center for assistance.
Another object of the present invention is to provide a clutch fault detection and clutch assist
system that enables the driver to safely negotiate the vehicle in case of clutch “fault state” by
downshifting the gear and moving the vehicle to roadside or continue to drive the vehicle in
only one low gear, thereby ensuring safety of the occupants.
Still another object of the present invention is to provide a clutch fault detection and clutch
assist system that enables the driver to carry out clutch operation without the intervention of
vehicle occupant.
Another object of the present invention is to provide a clutch fault detection and clutch assist
system that take charge of clutch disengaging function even in case of clutch “fault state”.
SUMMARY OF THE INVENTION
In case of malfunction state of “slave cylinder”, a slave cylinder (14) is incapable to develop the required hydraulic pressure (due to internal / external leakages in cylinder or hoses or for any other reason) to operate the clutch release lever (28) to disengage the clutch and such condition can lead to dangerous conditions, wherein the clutch becomes inoperative and the driver is not able to downshift the gear while at a higher speed. With the system 100 and method of the proposed invention, the malfunction state of clutch “slave cylinder” is automatically detected by a sensing mechanism/ sensing cylinder 16 using hydraulic principle. More specifically, a small floating piston (17) inside a hydraulic chamber (16) acts as a sensing mechanism to detect the malfunction state of clutch slave cylinder (14). One side of floating piston (17) is subjected to pressure from vehicle clutch “slave cylinder” (14) and other side of floating piston (17) is subjected to pressure from vehicle clutch “Master Cylinder” (12). The magnitude of differential pressure on floating piston (17) decides the state of clutch “Slave Cylinder” (14) (working or malfunctioning). The pressure developed inside the clutch “Master cylinder” (12) at this juncture directs the flow of oil either to clutch

“Slave Cylinder” (14) in case of “no fault” state (as illustrated in FIG. 2) or to an auxiliary hydraulic cylinder (18) in case of “fault” state (as illustrated in FIG. 3). In case of “fault” state, the auxiliary hydraulic cylinder (18) actuates the clutch release fork to cause clutch disengagement. Also upon detection of above malfunction state, the user will be intimated (warned) through audible warning about the failure. Further, case of “no fault” state, the “Slave Cylinder” (14) actuates the clutch release fork to cause clutch disengagement.
BRIEF DESCRIPTION OF THE ACCOMANYING DRAWINGS
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 a schematic representation of a clutch fault detection and clutch assist system along with various elements thereof and intern-connection between the various elements thereof in accordance with an embodiment of the present disclosure;
FIG. 2 illustrates a schematic representation of the clutch fault detection and clutch assist system of FIG. 1, depicting pressures inside various chambers of the system, when clutch pedal is fully pressed and “no fault” condition exists; and
FIG. 3 illustrates a schematic representation of the clutch fault detection and clutch assist system of FIG. 1, depicting pressures inside various chambers of the system, when clutch pedal is fully pressed and “fault” condition is detected.
DETAILED DESCRIPTION OF THE INVENTION
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.
Referring now to the drawings wherein the showings are for the purpose of illustrating a preferred embodiment of the invention only, and not for the purpose of limiting the same. Fig. 1 illustrates a schematic representation of a clutch fault detection and clutch assist system (100) (hereinafter referred to as “system”) along with various elements thereof and inter-connection between the various elements thereof in accordance with an embodiment of the present disclosure. The system (100) not only detects "Fault state" in clutch slave cylinder during manual clutch operation of the clutch but also assists in disengaging the clutch in such condition, thereby avoiding the dangerous situations arising due to "Fault state" of the slave cylinder, wherein the driver is unable to downshift the gear while at driving at a higher speed, thereby leading to accidents due to vehicle getting out of control. The system (100) enables the driver to safely negotiate the vehicle in case of clutch “fault state” by downshifting the gear and moving the vehicle to roadside or continue to drive the vehicle in only one low gear, thereby ensuring safety of the occupants. The system (100) further alerts the driver incase "Fault state" in clutch slave cylinder is detected through audible alert signal, thereby prompting the driver to take necessary precautions such as approaching the nearest service center for assistance. The system (100) operates on hydraulic principle along with malfunction detection mechanism and uses additional elements such as a sensing cylinder (16) and an auxiliary actuation cylinder (18).
The clutch fault detection and clutch assist system (100) includes a clutch pedal (04) disposed along with the brake pedal (06) and the accelerator pedal (08). The clutch pedal (04) is disposed in the cabin and is accessible to the driver, upon actuation of the clutch pedal, the clutch disengagement is initiated, provided that the “slave cylinder” is functioning properly and there are no external internal leakages that may adversely affect the clutch operation. The clutch fault detection and clutch assist system (100) further includes a master cylinder (12) with a piston (13) disposed therein, a slave cylinder (14) with a piston (15) disposed therein, a sensing cylinder (16) with a piston (17) disposed therein, an auxiliary cylinder (18) with a piston (19) disposed therein. The clutch fault detection and clutch assist system (100) further includes a first cylinder (22) with a piston (23) disposed therein and the second cylinder (24)

with piston (25) disposed therein. The piston (25) divides the second cylinder chamber (24) between two portions 24a and 24b, with spring in one portion (24a). Further, a non-return valve (NRV) (26) connects two portions (24a) and (24b) of the second cylinder chamber (24). In case of “No fault” condition, refer FIG. 2, when clutch pedal (04) is further pressed from its position, the fluid in the master cylinder (12) is at high pressure as there are no leakages. This high pressure fluid is transmitted from the master cylinder (12) to the first portion (24a), this high pressure fluid entering the first portion (24a) cannot move the piston (25) due to spring forces of the spring S1 resisting the movement of the piston 25, but the high pressure fluid forces the pilot operated NRV (26) to open and directs the “High Pressure” fluid from “RH side” (24a) portion to “LH side” portion (24b) of the cylinder chamber (24). This in turn, directs the “High Pressure” fluid form Port “E” of cylinder (24) to the slave cylinder (14), via Port “H”. Accordingly, the piston (15) of the slave cylinder (14) moves outwards along with the piston rod (15a) and causes rotation of the clutch release lever (28) about its center to disengage the clutch. The mechanical connection between the end of release lever 28 and respective piston rod is such that the release lever 28 acts in one direction only. i.e. when the respective piston rod move in outward direction. Specifically, the connection between the end of release lever 28 and respective piston rod is such that the piston rod can only push the release lever 28 but the release lever 28 will not be able to pull the respective rod. Hence, in this case, even if the piston rod 15a pushes the release lever 28, the release lever 28 will not be able to pull the piston rod 19a, hence there will not be any clash between two cylinders 14 and 19. The clutch remains in “disengaged” state as long as clutch pedal is in fully pressed condition.
Similarly, when “Fault” is there in the clutch “Slave” cylinder 14, refer FIG. 3, then clutch pedal is further pressed from its position, due to fault in the clutch “Slave Cylinder” 15, any further flow of oil from sensing cylinder (16), via Port “K” to Cylinder (3) and Port “J” is unable to create a “High Pressure” region in bottom side of the slave cylinder (15) and it remains in “Low Pressure” state and cannot actuate the clutch release lever (28) about its center to disengage the clutch.
“High Pressure” fluid flow from the master cylinder (12), moves from the master cylinder (12) to the cylinder portion (24a) but cannot move the piston 25 nor can the fluid pressure open the NRV, the high pressure fluid moves from the master cylinder (12) to the cylinder (22) via the Port “A” and Port “B”. From there, “High Pressure” fluid flows from Port “C” of

cylinder 22 to auxiliary cylinder (18), via port “F”. The high pressure fluid then moves the piston 19 of auxiliary cylinder (18) outwards and rotates the clutch release lever (28) about its center to disengage the clutch. The clutch remains in “disengaged” state as long as clutch pedal is in fully pressed condition.
In case of malfunction state of “slave cylinder”, a slave cylinder (14) is incapable to develop the required hydraulic pressure (due to internal / external leakages in cylinder or hoses or for any other reason) to operate the clutch release lever (28) to disengage the clutch and such condition can lead to dangerous conditions, wherein the clutch becomes in-operative and the driver is not able to downshift the gear while at a higher speed. With the system 100 and method of the proposed invention, the malfunction state of clutch “slave cylinder” is automatically detected by a sensing mechanism/ sensing cylinder 16 using hydraulic principle. More specifically, a small floating piston (17) inside a hydraulic chamber (16) acts as a sensing mechanism to detect the malfunction state of clutch slave cylinder (14). One side of floating piston (17) is subjected to pressure from vehicle clutch “slave cylinder” (14) and other side of floating piston (17) is subjected to pressure from vehicle clutch “Master Cylinder” (12). The magnitude of differential pressure on floating piston (17) decides the state of clutch “Slave Cylinder” (14) (working or malfunctioning). The pressure developed inside the clutch “Master cylinder” (12) at this juncture directs the flow of oil either to clutch “Slave Cylinder” (14) in case of “no fault” state (as illustrated in FIG. 2) or to an auxiliary hydraulic cylinder (18) in case of “fault” state (as illustrated in FIG. 3). In case of “fault” state, the auxiliary hydraulic cylinder (18) actuates the clutch release fork to cause clutch disengagement. Also upon detection of above malfunction state, the user will be intimated (warned) through audible warning about the failure. Further, case of “no fault” state, the “Slave Cylinder” (14) actuates the clutch release fork to cause clutch disengagement. Fig. 2 illustrates a schematic representation of the clutch fault detection and clutch assist system 1, depicting pressures inside various chambers of the system along the oil flow path, when clutch pedal is fully pressed and “no fault” condition exists.
FIG. 3 illustrates a schematic representation of the clutch fault detection and clutch assist system of (100), depicting pressures inside various chambers of the system along the oil flow path, when clutch pedal is fully pressed and “fault” condition is detected.
Advantages:
A clutch fault detection and clutch assist system that

• obviates the drawbacks of the conventional clutch system;
• not only detects "Fault state" in clutch slave cylinder during manual clutch operation of the clutch but also assists in disengaging the clutch in such condition, thereby avoiding the dangerous situations arising due to "Fault state" of the slave cylinder;
• alerts the driver incase "Fault state" in clutch slave cylinder is detected through audible alert signal, thereby prompting the driver to take necessary precautions such as approaching the nearest service center for assistance;
• enables the driver to safely negotiate the vehicle in case of clutch “fault state” by downshifting and moving the vehicle to roadside or continue to drive the vehicle in only one low gear, thereby ensuring safety of the occupants;
• enables the driver to carry out clutch operation without the intervention of vehicle occupant; and
• enables the driver to take charge of clutch disengaging function even in case of clutch “fault state”.

Referral Numerals:
Reference Number Description
(100) clutch fault detection and clutch assist system
(04) a clutch pedal;
(06) brake pedal
(08) accelerator pedal
(12) a master cylinder, with a piston (15) disposed therein, a sensing cylinder (16) with a piston (17) disposed therein, an auxiliary cylinder (18) with a piston (19) disposed therein
(13) a piston of the master cylinder (12)
(14) a slave cylinder
(15) a piston received in the slave cylinder (14)
(15a) a piston rod of piston 15
(16) a sensing cylinder

(17) a piston received in the sensing cylinder
(18) an auxiliary cylinder
(19) a piston received in the auxiliary cylinder
(22) a first cylinder
(23) a piston received in the first cylinder (22)
(24) a second cylinder;
(25) a piston received within the second cylinder and diving interior of the second cylinder in first and second portions;
(24a and 24b) portions of the second cylinder;
S1 spring disposed in cylinder portion 24a
(26) a non-return valve
S2 Spring S2

WE CLAIM
1. A clutch control system in a vehicle comprising a master cylinder (12), a sensing cylinder (16) and a slave cylinder (14), an auxiliary cylinder (18) wherein said master cylinder (12) is connected to first cylinder (22) and second cylinder (24); said second cylinder (24) contains a piston (25) which divides the second cylinder chamber (24) in two portions (24a) and (24b) with spring in one portion (24a); two portions (24a) and (24b) of the second cylinder chamber (24) are connected with a non-return valve (NRV) (26); wherein said sensing cylinder (16) provided with floating piston (17) detects the clutch state through magnitude of differential pressure on floating piston (17) and said auxiliary cylinder (18) moves high pressure fluid through piston of auxiliary cylinder (18) outwards and rotates the clutch release lever (28) about its center to disengage the clutch.
2. The clutch control system in a vehicle as claimed in claim 1 wherein when high pressure fluid flow from the master cylinder (12) to the cylinder portion (24a), due to fault operation condition in cylinder (14), the fluid pressure fluid neither moves the piston (25) of cylinder (24) not open the NRV (26) then the high pressure fluid moves from the master cylinder (12) to the cylinder (22) and further to auxiliary cylinder (18); the high pressure fluid then moves the piston of auxiliary cylinder (18) outwards and rotates the clutch release lever (28) about its center to disengage the clutch.
3. The clutch control system in a vehicle as claimed in claim 1 wherein said sensing cylinder (16) is having a floating piston (17) for providing a sensing mechanism to detect the working of malfunction state of clutch slave cylinder (14).
4. The clutch control system in a vehicle as claimed in claim 3 wherein said sensing mechanism is attained when one side of floating piston (17) of sensing cylinder (16) is subjected to pressure from vehicle clutch slave cylinder (14) and other side of floating piston (17) is subjected to pressure from vehicle clutch master cylinder (12); magnitude of differential pressure on floating piston (17) detects the state of clutch slave cylinder (14).
5. The clutch control system in a vehicle as claimed in claim 1 wherein said sensing cylinder (16) detects the clutch state and the pressure developed inside the clutch master cylinder (12) directs the flow of oil to an auxiliary hydraulic cylinder (18) which actuates the clutch release fork (28) to cause clutch disengagement in case of

“fault” state OR to clutch slave cylinder (14) which actuates the clutch release fork (28) to cause clutch disengagement.
6. A clutch control method for a clutch fault detection and clutch assist system in a
vehicle comprising:
detecting clutch fault in a vehicle through audible alert signal provided by a sensing cylinder (16) an thereby prompting the driver to take necessary precautions such as approaching the nearest service center for assistance.
assisting gear shifting to disengage the clutch with auxiliary cylinder (18) that enables the driver to safely negotiate the vehicle in case of clutch “fault state” by down shifting the gear and moving the vehicle to roadside or continue to drive the vehicle in only one low gear, thereby ensuring safety of the occupants.
7. The clutch control method for a clutch fault detection and clutch assist system in a
vehicle as claimed in claim 6 wherein said clutch fault is detected with signal
provided by a sensing cylinder (16) with floating piston (17) through magnitude of
differential pressure of fluid on floating piston (17) and said auxiliary cylinder (18)
moves high pressure fluid through piston of auxiliary cylinder (18) outwards and
rotates the clutch release lever (28) about its center to disengage the clutch assisting
shifting of gear in clutch fault state.