FORM 2
THE PATENTS ACT 1970
[39 OF 1970]
&
The Patents Rules, 2003
COMPLETE SPECIFICATION
[See section 10 and rule 13]
TITLE: “A PNEUMATIC BRAKING SYSTEM FOR A VEHICLE AND A METHOD
THEREOF”
NAME AND ADDRESS OF THE APPLICANT:
TATA MOTORS LIMITED, having address at 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.

TECHNICAL FIELD
Present disclosure generally relates to the field of automobiles. Particularly, but not exclusively, the present disclosure relates to a pneumatic braking system and a method of braking a vehicle in an event of failure in at least one of a brake line circuits and signal circuits of the vehicle.
BACKGROUND OF DISCLOSURE:
Now-a-days, demand for automobiles is increasing at a rapid pace. Many vehicles emerging in the market come with various smart and advanced features such as anti-lock braking system (ABS), electronic braking system (EBS) etc., that are mostly controlled by an electronic control unit (ECU) of the vehicle. A braking system is the most critical system in a vehicle for deceleration of the vehicle as per the requirement of a driver for safety purpose. Various braking systems are classified based on use of a working fluid such as hydraulic braking system, pneumatic braking system, mechanical braking system and electromagnetic braking system. Pneumatic braking system (or) air braking system is commonly used in all the commercial vehicles such as trucks and buses considering a large braking force is required to decelerate and stop the vehicle. Further, as compressed air can be easily provided to brakes through a compressor, the pneumatic air system is more reliable than any other braking system. Generally, the compressor produces the compressed air and supplies the same into a storage tank which stores the compressed air at a pressure higher than an atmospheric pressure. A foot control valve (or) a brake pedal is actuated by the driver to initiate brake application by allowing the compressed air to pass through brake chambers connected to a disc or drum brakes that are installed on a rotor of a vehicle wheel. Each brake chamber includes a diaphragm, a pushrod, and a return spring. The compressed air actuates the diaphragm to provide a mechanical force that actuates a brake shoe or brake pads within a brake drum. The brake shoes come into contact with a rotating drum (or) a brake drum to decelerate and stop the vehicle due to frictional contact between the brake shoes and the brake drum. In case of the disc brakes, the brake pad holds and locks rotation of the rotor for stopping the vehicle.
Conventionally, the air braking system includes a front braking circuit and a rear braking circuit that are configured to supply braking force to a front brake unit and a rear brake unit connected to a front axle and a rear axle of the vehicle respectively. The front and rear braking circuits are connected to individual storage tanks and operate independently. Each of the front and rear braking circuits comprises a relay valve connected to the foot valve by a main supply circuit. A signal line

circuit is fluidly connected with the foot valve and the relay valve. The signal line circuit provides an actuation signal to the relay valve such that the compressed air from the main supply valve is transferred to a front axle brakes and a rear axle brakes. The actuation signal is provided by supplying the compressed air or the brake fluid at a faster rate through the signal line circuit to mitigate brake lag upon actuating the foot valve and thereby improving the brake response time of the vehicle. In an event of failure of the main supply circuit, the control unit detects a lack of pressure in the main supply circuit and provides a visual indication to a driver about a brake failure in at least one of the front and rear braking circuits. Therefore, in such cases, only a single braking circuit will be operational for decelerating and stopping the vehicle.
However, if there is a failure in the signal line circuit, no such visual indication is provided to the driver as the main supply line contains the compressed air required for braking. Consequently, if the driver actuates the brake pedal, the actuation signal will not be transmitted to the relay valve to enable flow of the compressed air through the main supply circuit. This is risky and results in severe accidents which jeopardizes the safety of a driver and passengers. Additionally, in some of the vehicles, the driver is misinformed about the signal line circuit being damaged. Therefore, a need exists for a braking system that provides correct indications to the driver, and which is capable of supplying the compressed air or the brake fluid in emergency conditions i.e., in an event of brake failure.
The present disclosure is intended to overcome one or more above stated limitations.
SUMMARY OF THE DISCLOSURE:
One or more shortcomings of a conventional pneumatic braking system are overcome, and additional advantages are provided through a system and a method of the present disclosure. Additional features and advantages are realized through the arrangement of the components of the system to supply a brake fluid to a front brake unit and a rear brake unit at a predefined pressure in an event of a brake failure due to leakage or rupture in at least one front and a rear brake unit of the pneumatic braking system. Other embodiments and aspects of the disclosure are described in detail herein and are considered a part of the claimed disclosure.

In one non-limiting embodiment of the present disclosure, a pneumatic braking system for a vehicle is disclosed. The pneumatic braking system comprises a front brake unit and a rear brake unit. A first brake circuit is fluidly connected with the front brake unit. A second brake circuit is fluidly connected with the rear brake unit. At least one reservoir is fluidly connected to the front brake unit and the rear brake unit. At least one reservoir is fluidly connected to the front brake circuit and the rear brake circuit. The at least one reservoir is configured to store and supply a brake fluid to the first brake circuit and the second brake circuit at a predefined pressure. A first control valve is fluidly connected with the first brake circuit and the second brake circuit. A relay valve is fluidly connected with the first control valve and the at least one reservoir. The relay valve is configured to receive a first actuation signal from the first control valve and supply the brake fluid to the front brake unit and the rear brake unit. At least one sensor is disposed between the first control valve and the relay valve and the at least one sensor is configured to determine a pressure of the brake fluid within the first brake circuit and the second brake circuit. An auxiliary brake circuit is fluidly connected with the relay valve and the at least one reservoir. The auxiliary brake circuit comprises a second control valve configured to provide a second actuation signal to the relay valve. Further, a control unit is communicatively coupled to the at least one sensor and the second control valve. The control unit is configured to receive a third actuation signal from the at least one sensor when the pressure of the brake fluid is lower than the predefined pressure and actuate the second control valve to supply the brake fluid to the front brake unit and the rear brake unit.
In an embodiment, the first control valve is fluidly connected to a brake pedal. The first control valve is configured to supply the brake fluid to the front brake unit and the rear brake unit through the relay valve.
In an embodiment, the relay valve comprises a first inlet in fluid communication with the at least one reservoir in the first brake circuit. The first inlet is configured to receive the brake fluid from the at least one reservoir at the predefined pressure. A second inlet is in fluid communication with the first control valve and the second inlet is configured to receive the brake fluid from the first control valve and generate the first actuation signal allow the brake fluid from the at least one reservoir to the front brake unit and the rear brake unit. A third inlet is in fluid communication with the second control valve. The third inlet is configured to receive

the brake fluid from the second control valve and generate the second actuation signal to supply the brake fluid to the front brake unit and the rear brake unit.
In an embodiment, the first actuation signal corresponds to the supply of the brake fluid from the first control valve to the first inlet of the relay valve.
In an embodiment, the first control valve is defined with at least two inlets and at least two outlets. The at least two inlets are connected to the at least one reservoir of the first brake circuit. The at least two outlets are connected to the relay valve of the second brake circuit.
In an embodiment, the system further comprises an alarm unit communicatively coupled to the control unit. The control unit is configured to activate the alarm unit to provide an acoustic warning upon receipt of the third actuation signal from the at least one sensor.
In an embodiment, the control unit is configured to provide a visual indication on a display unit associated with an instrument cluster of the vehicle upon receipt of the third actuation signal. The visual indication corresponds to a brake failure.
In an embodiment, the at least one sensor is at least one of a pressure gradient sensor and a flow rate sensor.
In an embodiment, the first control valve is at least one of a dual brake valve, foot brake valve, dual treadle valve, hydraulic brake valve and electric brake valve and brake pedal valve or by any means of brake pedal actuation.
Present disclosure also discloses a method of operating a pneumatic brake unit. The method comprises the steps of initially determining a pressure of a brake fluid within the first brake circuit and the second brake circuit by at least one sensor. The at least one sensor is fluidly connected with first control valve and a relay valve. The relay valve is fluidly connected to a second control valve. The first control valve is actuated by a driver to supply the brake fluid to the relay valve in order to generate a first actuation signal. Upon receiving the first actuation signal, the relay valve supplies the brake fluid to a front brake unit and a rear brake unit at a predefined pressure. The front brake unit and the rear brake unit are fluidly connected with the

relay valve. Further, the at least one sensor generates a third actuation signal upon detecting a pressure drop of the brake fluid within the first brake circuit and the second brake circuit. Later, a control unit actuates the second control valve to supply the brake fluid to the relay valve and generate a second actuation signal to supply the brake fluid from the relay valve to the front brake unit and the rear brake unit at the predefined pressure based on the third actuation signal from the at least one sensor. The control unit activates an alarm unit to generate an alert corresponding to a brake failure within at least one of the first brake circuit and the second brake circuit. Lastly, the control unit displays a visual indication corresponding to the brake failure on an instrument cluster of the vehicle.
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 description.
BRIEF DESCRIPTION OF ACCOMPANYING DRAWINGS:
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 description of an illustrative 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:
Fig. 1 is a schematic layout of a pneumatic braking system for a vehicle, in accordance with an embodiment of the present disclosure; and
Fig. 2 is a flow diagram depicting a method of operating the pneumatic braking system of Fig. 1.
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:
While the embodiments of 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 alternatives falling within the scope of the disclosure.
It is to be noted that a person skilled in the art would be motivated from the present disclosure and modify a system and a method for the purpose of achieving braking of a vehicle in an event of failure in at least one of a brake line circuit and a signal line circuit of the vehicle. However, such modification should be construed within the scope of the present 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 skill in the art having benefit of the description herein.
The terms “comprises”, “comprising”, or any other variations thereof used in the present disclosure, are intended to cover a non-exclusive inclusion, such that a system, a method, an apparatus or a device, 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, apparatus or the device. In other words, one or more elements in the system or the apparatus preceded by “comprises… a” does not, without more constraints, preclude the existence of other elements or additional elements in the system, the method, or the apparatus.
In the following description of the embodiments of the disclosure, reference is made to the accompanying figures that form a part hereof, and in which are shown, by way of illustration, specific embodiments in which the present disclosure may be practiced. These embodiments are described in sufficient detail to enable those skilled in the art to practice the present disclosure, and it is to be understood that other embodiments may be utilized and that, changes

may be made without departing from the scope of the present disclosure. The following description is, therefore, not to be taken in a limiting sense.
Embodiments of the present disclosure discloses a pneumatic braking system for a vehicle. Conventionally, a pneumatic braking system includes a front braking circuit and a rear braking circuit that are configured to supply braking force to a front brake unit and a rear brake unit connected to a front axle and a rear axle of the vehicle respectively. The front and rear braking circuits are connected to individual storage tanks and operate independently. Each of the front and rear braking circuits comprises a relay valve connected to the foot valve by a main supply circuit. A signal line circuit is disposed between the foot valve and the relay valve. The signal line circuit provides an actuation signal to the relay valve such that the compressed air from the main supply valve is transferred to a front axle brakes and a rear axle brakes. The actuation signal is provided by supplying the compressed air at a faster rate through the signal line circuit to mitigate brake lag upon actuating the foot valve. In an event of failure of the main supply circuit, the control unit detects a lack of pressure in the main supply circuit and gives visual indication to a driver of a brake failure in one of the front and rear braking circuits. However, if there is any failure in the signal line circuit, no such visual indication is given to the driver as the main supply line contains the compressed air required for braking. Consequently, if the driver actuates the brake pedal, the actuation signal will not be transmitted to the relay valve to enable flow of the compressed air through the main supply circuit. This is risky and results in severe accidents which jeopardizes the safety of the driver. Additionally, in some of the vehicles, the driver is misinformed by the control unit that the brakes are fully functional even if the signal line circuit is damaged.
In view of the above, a pneumatic braking system for a vehicle is disclosed. The system comprises a front brake unit and a rear brake unit. A first brake circuit is fluidly connected with the front brake unit. A second brake circuit is fluidly connected with the rear brake unit. At least one reservoir is configured to store and supply a brake fluid to the first brake circuit and the second brake circuit at a predefined pressure. A first control valve is fluidly connected with the first brake circuit and the second brake circuit. A relay valve is fluidly connected with the first control valve and the at least one reservoir. The relay valve is configured to receive a first actuation signal from the first control valve and supply the brake fluid to the front brake unit

and the rear brake unit. At least one sensor is disposed between the first control valve and the relay valve and the at least one sensor is configured to determine a predefined pressure of the brake fluid within the first brake circuit and the second brake circuit. An auxiliary brake circuit is fluidly connected with the relay valve and the at least one reservoir. The auxiliary brake circuit comprises a second control valve configured to provide a second actuation signal to the relay valve. Further, a control unit is communicatively coupled to the at least one sensor and the second control valve. The control unit is configured to receive a third actuation signal from the at least one sensor when the pressure of the brake fluid is lower than the predefined pressure and actuates the second control valve to supply the brake fluid to the front brake unit and the rear brake unit. This configuration of the at least one sensor and the auxiliary brake circuit provides the brake fluid to the front and rear brake units in case of any failure in the first and second brake circuits. This ensures effective braking of the vehicle in emergency conditions to prevent accidents and provide safety to a driver and passengers seated inside the vehicle. Further, the auxiliary brake circuit is in communication with the control unit to provide a visual indication in an instrument cluster of the vehicle when there is a failure in the first and second brake circuits. This keeps the driver informed about a leakage or lack of pressure in the first and second brake circuits and appropriate repairs or maintenance should be done to the braking system.
Referring to Fig.1 which illustrates a schematic layout of the pneumatic braking system (100) for a vehicle (not shown in Figs.). The system (100) comprises a front brake unit (103) and a rear brake unit (105). The front brake unit (103) is connected with a pair of front wheels (not shown in Fig) of a front axle (not shown in Fig) and the rear brake unit (105) is connected to a pair of rear wheels (not shown in Fig) of a rear axle (not shown in Fig) of the vehicle. In an embodiment, the front brake unit (103) and the rear brake unit (105) comprises a brake chamber (103a) coupled to each wheel of the pair of the front and rear wheels. Each brake chamber (103a) comprises a diaphragm (not shown in Figs.), a pushrod (not shown in Figs.) connected to the diaphragm and a return spring (not shown in Figs.). The diaphragm is configured to actuate the push rod to apply mechanical force on a rotor (not shown in Figs.) of the front wheels. In an embodiment, a disc-type brake (not shown in Figs.) may be used for each wheel of the pair of front wheels and the pair of rear wheels and however, this cannot be construed as

a limitation and a drum type brake (not shown in Figs.) and the disc-type brakes may be used interchangeably for the pair of front wheels (not shown in Figs.) and the pair of rear wheels (not shown in Figs.) depending on the requirement.
A first brake circuit (102) is fluidly connected with the front brake unit (103) and a second brake circuit (104) is fluidly connected with the rear brake unit (105). The first brake circuit (102) is configured to supply a brake fluid to the front brake unit (103) at a predefined pressure to decelerate and stop the front wheels. The second brake circuit (104) is configured to supply the brake fluid to the rear brake unit (105) at the predefined pressure to decelerate and stop the rear wheels of the vehicle. The front brake unit (103) and the rear brake unit (105) are constructionally similar in configuration and operate independently for braking. In an embodiment, the first and second brake circuits (102, 104) may operate in tandem with each other to decelerate and stop the pair of front and rear wheels simultaneously. The first brake circuit (102) comprises a main supply path (102b) and a signal supply path (102a). The main supply path (102b) is structured as a conduit to supply the brake fluid to the front brake unit (103). The signal supply path (102a) is configured to provide a signal to activate the supply of the brake fluid from the main supply path (102b) to the front brake unit (103). In an embodiment, the signal supply path (102a) is also structured as a conduit having lesser diameter than that of the main supply path (102b). In an embodiment, the brake fluid from the signal supply path (102a) is supplied at an increased velocity compared to the velocity of the brake fluid supplied through the main supply path (102a).
At least one reservoir (106) is fluidly connected with the first brake circuit (102) and the second brake circuit (104) respectively. The at least one reservoir (106) is configured to store and supply the brake fluid to each of the first brake circuit (102) and the second brake circuit (104) at a predefined pressure. In an embodiment, two reservoirs (106) are fluidly connected with the first brake circuit (102) and the second brake circuit (104) respectively. In an embodiment, each reservoir (106) stores compressed air at the predefined pressure which is used as the brake fluid. In an embodiment, the compressed air is generated by a compressor (150) positioned proximate to an engine (not shown in Figs.) of the vehicle. In an embodiment, at least one of a reciprocating air compressor, rotary air compressor, centrifugal air compressor and axial air compressor may be used to generate compressed air based on the requirement. In an embodiment, the

compressed air generated by the compressor (150) is transferred to each reservoir (106) through an air processing unit (152). In an embodiment, the air processing unit (152) is disposed between the compressor (150) and each reservoir (106). The air processing unit (152) is configured to filter the compressed air generated by the compressor (150) and supplies useable brake fluid into each reservoir (106) without any dust, moisture and particulates. In an embodiment, the air processing unit (152) may include a particulate filter, and/or sediment filter to purify the compressed air from impurities. The air processing unit (152) is fluidly connected with the at least one reservoir (106) associated with each of the first brake circuit (102) and the second brake circuit (104). In an embodiment, the air processing unit may be connected to the at least one reservoir (106) through a system protection valve (154). The system protection valve (154) may include various input and output ports (not shown in Figs.) configured to provide the compressed air on demand to various auxiliary systems of the vehicle such as a foldable seats, automated armrest etc.
The pneumatic braking system (100) further comprises a first control valve (108) fluidly connected with the first brake circuit (102) and the second brake circuit (104). The first control valve (108) is a dual brake valve having at least two inlets (108a) and the at least two outlets (108b). Each inlet (108a) of the at least two inlets (108a) is fluidly connected with each reservoir (106) associated with the first brake circuit (102) and the second brake circuit (104). In an embodiment, the first control valve (108) comprises a housing (not shown in Fig) and at least one plunger (not shown in Fig) which is displaceable within the housing. The at least one plunger is fluidly connected to a brake pedal (not shown in Figs.) disposed inside a cabin (not shown in Figs.) of the vehicle. The brake pedal is operated to actuate the first control valve (108) to supply the brake fluid through the at least two outlets (108b) upon displacement of the at least one plunger. The brake fluid is then transferred from the first control valve (108) to the front brake unit (103) through a relay valve (110).
The relay valve (110) is fluidly connected between the first control valve (108) and the at least one reservoir (106) of the first brake circuit (102). The relay valve (110) is configured to receive a first actuation signal (140) from the first control valve (108) and supply the brake fluid to the front brake unit (103). The relay valve (110) comprises a first inlet (110a), a second inlet (110b) and a third inlet (110c). In an embodiment, the first inlet (110a) may be in a normally closed

position. In an embodiment, the second inlet (110b) along with the third inlet (110c) may be in an open position. The first inlet (110a) is in fluid communication with the at least one reservoir (106) associated with the first brake circuit (102). The first inlet (110a) is configured to receive the brake fluid from the at least one reservoir (106) at the predefined pressure. The second inlet (110b) is in fluid communication with the first control valve (108) through the signal supply path (102a). The second inlet (110b) is configured to receive the brake fluid from the first control valve (108) and generate a first actuation signal (140) to allow the supply of the brake fluid from the at least one reservoir (106) to the front brake unit (103). In other words, when the brake pedal connected with the first control valve (108) is operated, the brake fluid is supplied into the second inlet (110b). This brake fluid generates a force within the relay valve (110) that is sufficient to open the first inlet (110a) such that the brake fluid is supplied from the at least one reservoir (106) to the front brake unit (103) and the rear brake unit (105) through the first inlet (110a). A third inlet (110c) is configured to receive the brake fluid and generate a second actuation signal (142) to supply the brake fluid to the front brake unit (103). In an embodiment, an anti-compounding relay valve (110) is used in the first brake circuit (102) and the second brake circuit (104).
In an embodiment, the second brake circuit (104) also comprises the main supply path (104a), the signal supply path (104b) and the relay valve (110) which is fluidly connected to the first control valve (108) and the at least one reservoir (106) associated with the second brake circuit (104). The relay valve (110) of the second brake circuit (104) is configured to supply the brake fluid from the main supply path (104a) of the second brake circuit (104) to the rear brake unit (105) to decelerate and stop the pair of rear wheels of the vehicle.
At least one sensor (112) is disposed between the first control valve (108) and the relay valve (110) associated with the first brake circuit (102) and the second brake circuit (104). The at least one sensor (112) is configured to determine a predefined pressure of the brake fluid within the first brake circuit (102) and the second brake circuit (104). In an embodiment, the at least one sensor (112) detects a pressure ramping rate or a pressure gradient within the signal supply path upon actuation of the brake pedal. In an embodiment, the at least one sensor (112) may be a pressure gradient sensor, a flow rate sensor, and any suitable sensors to detect the pressure

ramping rate and flow characteristics of the brake fluid within the first and second brake circuits (102, 104).
Furthermore, an auxiliary brake circuit (114) is fluidly connected with the relay valve (110) and the at least one reservoir (106) associated with the first brake circuit (102) and the second brake circuit (104). The auxiliary brake circuit (114) comprises a second control valve (116) configured to provide the second actuation signal (142) to the relay valve (110). The second control valve (116) is fluidly connected with the third inlet (110c) of the relay valve (110) which is associated with the first brake circuit (102) and the second brake circuit (104) respectively. In an embodiment, the second control valve (116) may be a 3/2 solenoid valve having three ports which are input, output, and an exhaust ports. In an embodiment, two ports are pneumatically operated, and one port is electrically operated. The second control valve (116) may be electronically connected to an alarm unit (130) of a vehicle. The alarm unit (130) is configured to provide an acoustic alert to the driver upon actuation of the second control valve (116). In an embodiment, the alarm unit (130) may be communicatively connected to an instrument cluster (125) of the vehicle to provide a feedback to the driver. In an embodiment, the alarm unit (130) provides an acoustic warning to the driver corresponding to the brake failure in the first and second brake circuits (102, 104).
The pneumatic braking system (100) further comprises a control unit (120). In an embodiment, the control unit (120) may be an electronic control unit (ECU) of the vehicle. The control unit (120) is communicatively coupled with the at least one sensor (112), the auxiliary brake circuit (114), the alarm unit (130) and the instrument cluster (125). The control unit (120) is configured to receive a third actuation signal (144) from the at least one sensor (112) when the pressure of the brake fluid is lower than the predefined pressure. The control unit (120) actuates the second control valve (116) of the auxiliary brake circuit (114) upon receiving the third actuation signal (144). The second control valve (116) is configured to supply the brake fluid to the third inlet (110b) of the relay valve (110) and generate the second actuation signal (142) such that, the relay valve (110) is actuated to supply the brake fluid to the front brake unit (103) and the rear brake unit (105).

Present disclosure also discloses a method (200) for operating the pneumatic braking system (100). Referring to Fig. 2, the method (200) of operating the pneumatic braking system (100) in an event of a brake failure in the first brake circuit (102) or the second brake circuit (104) is disclosed. In an embodiment, the brake failure may occur in a main supply path (102a, 104a) or a signal supply path (102b, 104b) due to rupture in the corresponding conduits of the first brake circuit (102) and/or the second brake circuit (104). The method (200) comprises the steps of initially actuating the first control valve (108) to supply the brake fluid to the relay valve (110) and generate the first actuation signal (140). In an embodiment, the first control valve (108) may be actuated by operating the brake pedal by the driver. At step 202, the relay valve (110) gets activated upon receiving the first actuation signal (140), to supply the brake fluid to the front brake unit (103) and the rear brake unit (105) at the predefined pressure. In an embodiment, compressed air may be used as the brake fluid. In an embodiment, the relay valve opens the first inlet (110a) to allow the passage of the brake fluid from the at least one reservoir (106) to the front and rear brake units (103, 105). At step 203, the at least one sensor (112) determines pressure of the brake fluid within the first brake circuit (102) and the second brake circuit (104). In an embodiment, a pressure ramp rate within the signal supply path (102b, 104b) is determined by the at least one sensor (112). The pressure ramp rate corresponds to a rise in pressure of the brake fluid within the signal supply path (102b, 104b) between the first control valve (108) and the relay valve (110) upon actuation of the brake pedal. At step 204, the at least one sensor (112) generates a signal upon detecting a drop in pressure of the brake fluid within the first brake circuit (102) and/or the second brake circuit (104). The drop in pressure corresponds to a decrease in the predefined pressure of the brake fluid within the signal supply path (102b, 104b) of the first brake circuit (102) and the second brake circuit (104). Further, at step 205, the control unit (120) receives the third actuation signal (144) from the at least one sensor (112) to actuate the second control valve (116). The second control valve (116) supplies the brake fluid to the third inlet (110c) to generate a second actuation signal (142). Upon receipt of the second actuation signal (142), the relay valve (110) gets activated to supply the brake fluid to the front brake unit (103) and the rear brake unit (105) at the predefined pressure at step 205. Later, at step 206, the control unit (120) activates the alarm unit (130) to generate an alert corresponding to the brake failure within the at least one of the first brake circuit (102) and the second brake circuit (104). Lastly, at step 207, the control unit (120) provides a visual indication

corresponding to the brake failure on an instrument cluster (125) of the vehicle. In an embodiment, the instrument cluster (125) may display a notification indicating the brake failure in the first and second brake circuits (102, 104) to alert the driver to make necessary repairs to the main supply path (102a, 104a) and the signal supply path (102b, 104b)) of the first and second brake circuits (102, 104).
In an embodiment, a modulator unit (115) is connected to the brake chamber (103a) and is disposed in the first brake circuit (102) and the second brake circuit (104). The modulator unit (115) is provided to regulate the supply of the brake fluid from the relay valve (110) to the brake chamber (103a). In an embodiment, the modulator unit (115) may be at least one of an anti-lock braking system (ABS) or an electronic braking system (EBS) which are associated with the electronic control unit (ECU) of the vehicle. In an embodiment, the preferred brake fluid used in the pneumatic braking system (100) of the present disclosure is compressed air.
In an embodiment, the predefined pressure of the brake fluid is in a range of 1 bar to 14 bar. However, this cannot be construed as a limitation and the predefined pressure value will depend on a type of vehicle and capacity of the pneumatic braking system (100).
In an embodiment, the at least one sensor (112) continuously monitors the pressure of the brake fluid within the signal supply path (102b, 104b) and sends a signal corresponding to a pressure drop observed within the first and second brake circuits (102, 104).
The pneumatic braking system (100) of the present disclosure can be easily installed in variety of the vehicles such as commercial as well as passenger vehicles to achieve effective braking even in a condition of a brake circuit failure. Advantageously, this makes the system safe and reliable irrespective of different running conditions.
The pneumatic braking system (100) of the present discloses instantly activates the alarm unit (130) upon activation of the second control valve (116) of the auxiliary brake circuit (114). This alerts the driver about the situation and provides information about the failure in the first and second brake circuits (102, 104). This ensures safety of the driver and co-passengers traveling in the vehicle.

The pneumatic braking system (100) of the present disclosure ensures safety of pedestrians crossing the road and in a vicinity of the vehicle by activating the auxiliary brake circuit (114) for decelerating and stopping the vehicle even at a failure condition of the first and second brake circuits (102, 104).
The pneumatic braking system (100) of the present disclosure provides a braking force to the vehicle even when there is a failure in any of the first and the second brake circuits. This effectively prevents accidents to the vehicle caused due to the brake failure and does not require immediate assistance upon failure of any brake circuit. This reduces significant costs incurred in maintenance and repairs of the vehicle.
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.
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.
Reference numerals:

Part Numeral
Pneumatic braking System 100
Method 200
First brake circuit 102
Main supply path 102a, 104a
Signal supply path 102b, 104b
Front brake unit 103
Brake chamber 103a

second brake circuit 104
Rear brake unit 105
At least one reservoir 106
First control valve 108
At least two inlets 108a
At least two outlets 108b
Relay valve 110
First inlet 110a
Second inlet 110b
Third inlet 110c
At least one sensor 112
Auxiliary brake circuit 114
Modulator unit 115
Second control valve 116
Control unit 120
Instrument cluster 125
Alarm unit 130
First actuation signal 140
Second actuation signal 142
Third actuation signal 144
Compressor 150
Air processing unit 152
System protection valve 154

We claim:
1. A pneumatic braking system (100) for a vehicle, the system (100) comprising:
a front brake unit (103) and a rear brake unit (105);
a first brake circuit (102) fluidly connected with the front brake unit (103);
a second brake circuit (104) fluidly connected with the rear brake unit (105);
at least one reservoir (106) fluidly connected to the first brake circuit (102) and the second brake circuit (104), the at least one reservoir (106) configured to store and supply a brake fluid to each of the first brake circuit (102) and the second brake circuit (104) at a predefined pressure;
a first control valve (108) fluidly connected with the first brake circuit (102) and the second brake circuit (104), and a relay valve (110) fluidly connected with the first control valve (108) and the at least one reservoir (106), wherein the relay valve (110) is configured to receive a first actuation signal (140) from the first control valve (108) and supply the brake fluid to the front brake unit (103) and the rear brake unit (105);
at least one sensor (112) disposed between the first control valve (108) and the relay valve (110), wherein the at least one sensor (112) is configured to determine a pressure of the brake fluid within the first brake circuit (102) and the second brake circuit (104);
an auxiliary brake circuit (114) fluidly connected with the relay valve (110) and the at least one reservoir (106), the auxiliary brake circuit (114) comprises a second control valve (116) configured to provide a second actuation signal (142) to the relay valve (110); and
a control unit (120) communicatively coupled to the at least one sensor (112) and the second control valve (116);
wherein the control unit (120) is configured to receive a third actuation
signal (144) from the at least one sensor (112) when the pressure of the brake
fluid is lower than the predefined pressure and actuate the second control valve
(116) to supply the brake fluid to the front brake unit (103) and the rear brake
unit (105).

2. The pneumatic braking system (100) as claimed in claim 1, wherein the first control valve (108) is fluidly connected to a brake pedal, and the first control valve (108) is configured to supply the brake fluid to the front brake unit (103) and the rear brake unit (105) through the relay valve (110).
3. The pneumatic braking system (100) as claimed in claim 1, wherein the relay valve (110) comprises:
a first inlet (110a) in fluid communication with the at least one reservoir (106) in the first brake circuit (102); wherein the first inlet (110a) is configured to receive the brake fluid from the at least one reservoir (106) at the predefined pressure;
a second inlet (110b) in fluid communication with the first control valve (108), the second inlet (110b) is configured to receive the brake fluid from the first control valve and generate the first actuation signal (140) to allow the brake fluid from the at least one reservoir (106) to the front brake unit (103) and the rear brake unit (105); and
a third inlet (110c) in fluid communication with the second control valve (116), the third inlet (110c) is configured to receive the brake fluid from the second control valve (116) and generate the second actuation signal (142) to supply the brake fluid to the front brake unit (103) and the rear brake unit (105).
4. The pneumatic braking system (100) as claimed in claim 3, wherein the first actuation signal (140) corresponds to the supply of the brake fluid from the first control valve (108) to the first inlet (110a) of the relay valve (110).
5. The pneumatic braking system (100) as claimed in claim 1, wherein the first control valve (108) is defined with at least two inlets (108a) and at least two outlets (108b), and the at least two inlets (108a) are connected to the at least one reservoir (106) of the first brake circuit (102) and the at least two outlets (108b) connected to the relay valve (110) of the second brake circuit (104).
6. The pneumatic braking system (100) as claimed in claim 1, comprises an alarm unit (130) communicatively coupled to the control unit (120), wherein the control unit (120)

activates the alarm unit (130) to provide an acoustic warning upon receipt of the third actuation signal (144) from the at least one sensor (112).
7. The pneumatic braking system (100) as claimed in claim 1, wherein the control unit (120) is configured to provide a visual indication on a display unit associated with an instrument cluster (125) of the vehicle upon receipt of the third actuation signal (144), and the visual indication corresponds to brake failure.
8. The pneumatic braking system (100) as claimed in claim 1, wherein the at least one sensor (112) is at least one of a pressure gradient sensor and a flow rate sensor.
9. The pneumatic braking system (100) as claimed in claim 1, wherein the first control valve (108) is at least one of a dual brake valve, foot brake valve, dual treadle valve, hydraulic brake valve and electric brake valve and brake pedal valve or by any means of brake pedal actuation.
10. A method (200) of operating a pneumatic brake system of a vehicle, the method (200) comprises of:
determining, by at least one sensor (112) a pressure of a brake fluid within a first brake circuit (102) and a second brake circuit (104), the at least one sensor (112) is fluidly connected with a first control valve (108) and a relay valve (110), the relay valve (110) is fluidly connected to a second control valve (116);
actuating by a driver, the first control valve (108) to supply the brake fluid to the relay valve and generate a first actuation signal (140);
supplying, by the relay valve the brake fluid to a front brake unit and a rear brake unit at a predefined pressure based on the first actuation signal (140), wherein the front brake unit (103) and the rear brake unit (105) are fluidly connected with the relay valve (110);
generating, a third actuation signal (144) by the at least one sensor (112) upon determining a pressure drop of the brake fluid within the first brake circuit (102) and the second brake circuit (104);

actuating, by a control unit (120), the second control valve (116) to supply the brake fluid to the relay valve (110) and generate a second actuation signal (142) to supply the brake fluid from the relay valve (110) to the front brake unit (103) and the rear brake unit (105) at the predefined pressure based on the third actuation signal (144) from the at least one sensor (112),
activating, by the control unit (120), an alarm unit (130) to generate an alert corresponding to a brake failure within at least one of the first brake circuit (102) and the second brake circuit (104); and
displaying, by the control unit (120), a visual indication corresponding to the brake failure, on an instrument cluster (125) of the vehicle.