FORM 2
THE PATENTS ACT, 1970
(39 OF 1970)
AND
THE PATENTS RULES, 2003
COMPLETE SPECIFICATION
(See Section 10; rule 13)
TITLE OF THE INVENTION
“AIR BRAKE SYSTEM AND OPERATING METHOD THEREOF”
APPLICANT(S)
TATA MOTORS LIMITED
Bombay House, 24 Homi Mody Street,
Hutatma Chowk, Mumbai 400 001, Maharashtra, India; an Indian company.
PREAMBLE TO THE DESCRIPTION
The following specification particularly describes the invention and the manner in which it is to be performed.

TECHNICAL FIELD OF THE INVENTION
Present disclosure, in general, relates to a field of automobiles. Particularly, but not exclusively, the present disclosure relates to an air-brake system for a vehicle having an internal combustion engine.
BACKGROUND OF THE INVENTION
Conventionally, air-brake systems are used on commercial vehicles such as heavy trucks and buses for controlling brake function of the vehicles. The air-brake system includes a compressor to pump air, with a governor to control the compressor, air-lines to allow the pressurized air to flow between air-brake system components, air tanks to store the compressed air and a brake pedal (referred as called a foot valve) to apply the brakes by directing compressed air from the air tanks to the vehicle brakes. Particularly, the air-brake systems rely on compressor to supply compressed air to air tanks which in turn supply air, under pressure, to the air-brake, thereby releasing the brakes. Release of the brakes requires air -tank pressure of at least 8.3 bar at normal operation of the air-brake system.
Typically, due to wear or faulty fittings of the components, unsuitable seals, corrosion, loose fitting gasket or flexible hose of brake-lines, the air- brake system develops air-leakage. Thus, when air-brake system leaks occur, the vehicle loses adequate continuous air pressure. This causes the brakes to set and lock if the air tank pressure is below the desired air tank pressure. In such condition, the driver of the vehicle tends to fill air in air tanks at engine full-throttle to release brakes of vehicle. That is, in order to perform refilling of air in air tanks the vehicle driver rapidly accelerate and decelerate the engine, thereby causing an increase and decrease in the engine RPM. This results in fuel loss states of the fuel in deceleration and acceleration and formation of lean and rich air-fuel mixture. Thus, further causing high fuel consumption and an increased emission due to large amount of unburnt fuel in exhaust gases.

Present disclosure is directed to overcome one or more limitations stated above or any other limitations associated with the known arts.
SUMMARY OF THE INVENTION
One or more shortcomings of the prior art are overcome by a system as claimed and additional advantages are provided through the device and a system 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.
In one non-limiting embodiment of the disclosure, an air-brake system for a vehicle having an internal combustion engine is disclosed. The air-brake system includes a front axle air tank, a rear axle air tank, a compressor for supplying compressed air to the front axle air tank and the rear axle air tank, a vehicle speed sensor configured for generating a vehicle speed signal indicative of a vehicle speed, air pressure sensors in communication with the front axle air tank and the rear axle air tank respectively, for measuring air tank pressure therein and generating air pressure signals. Further, the air-brake system includes a control module. The control module, in response to the vehicle speed signal indicative of a vehicle predetermined speed and at least one air pressure signal indicative of an air tank pressure value below a predetermined air tank pressure value, is configured to accelerate the engine until an engine RPM level corresponds to a predetermined threshold RPM level and actuate the compressor upon the engine acceleration to supply the compressed air to the front axle air tank and the rear axle air tank until the air tank pressure therein corresponds to the predetermined air tank pressure value.
In an embodiment, the predetermined air tank pressure value is equal or greater than 8.3 bar.

In an embodiment, the predetermined threshold engine RPM level corresponds to an engine maximum RPM threshold level.
In an embodiment, the engine upon attaining the predetermined threshold RPM level remains at the engine maximum RPM threshold level until the air tank pressure corresponds to the predetermined air tank pressure value and gradually comes to normal RPM value.
In an embodiment, the vehicle predetermined speed corresponds to a standstill speed at which the vehicle enters the vehicle standstill position.
In one non-limiting embodiment of the disclosure, a method of operating an air-brake system for a vehicle having an internal combustion engine is disclosed. The method includes aspects of operating the air-brake system and including a front axle air tank, a rear axle air tank, a compressor for supplying compressed air to the front axle air tank and the rear axle air tank, a vehicle speed sensor configured for generating a vehicle speed signal indicative of a vehicle speed, air pressure sensors in communication with the front axle air tank and the rear axle air tank, respectively, for measuring air tank pressure therein and generating air pressure signals. Further, method comprising steps of accelerating by control unit the engine in response to a vehicle speed signal indicative of a vehicle predetermined speed and at least one air pressure signal indicative of an air tank pressure value below a predetermined air tank pressure value and actuating, by control unit, the compressor upon the engine acceleration to deliver compressed air to the front axle air tank and the rear axle air tank until the air tank pressure therein equals to the predetermined air pressure value.
The foregoing summary is illustrative only and is not intended to be in any way limiting. In addition to the illustrative aspects, embodiments, and features described above, further aspects, embodiments, and features will become apparent by reference to the drawings and the following detailed description.

BRIEF DESCRIPTION OF THE ACCOMPANYING DRAWINGS
The novel features and characteristics 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 embodiments 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:
Figure. 1 illustrates a schematic block diagram of an air-brake system for a vehicle
having an internal combustion engine, in accordance with an embodiment of the
present disclosure.
Figure. 2 illustrates an engine performance curve, in accordance with an
embodiment of the present disclosure.
Figure. 3 is a flow-chart illustrating a method of operating an air-brake system for
a vehicle, in accordance with an embodiment of the present disclosure.
The figures depict embodiments of the disclosure for purposes of illustration only. One skilled in the art will readily recognize from the following description that alternative embodiments of the system and method illustrated herein may be employed without departing from the principles of the disclosure described herein.
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 forms the subject of the claims of the disclosure. It should be appreciated by those skilled in the art that, the conception and specific embodiments disclosed may be readily utilized as a basis for modifying other

devices, systems, assemblies and mechanisms 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 scope of the disclosure as set forth in the appended claims. The novel features which are believed to be characteristics of the disclosure, to its device or system, 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.
The terms “comprises”, “comprising”, or any other variations thereof, are intended to cover a non-exclusive inclusions, such that a system or a device that comprises a list of components or steps does not include only those components or steps but may include other components or steps not expressly listed or inherent to such setup or device. In other words, one or more elements in a system or apparatus proceeded by “comprises… a” does not, without more constraints, preclude the existence of other elements or additional elements in the system or apparatus.
Embodiments of the present disclosure relates to an air-brake system and a method of operating thereof. In an embodiment, the disclosed air-brake system facilitates an automatic acceleration of an engine and actuation of compressor to supply compressed air to a front axle air tank and a rear axle air tank of the air-brake system when the air tank pressure is below the predetermined air tank pressure value and the vehicle is at a predetermined speed. Additionally, the disclosed air-brake system is configured to maintain the engine at maximum RPM output level, while compressor continues to supply the compressed air to the front axle air tank and/or the rear axle air tank until the air tank pressure corresponds to the predetermined air tank pressure value. Thus, in an embodiment, the improved air-brake system discloses an automatic actuation of the compressor to supply compressed air to fill the front axle air tank and/or the rear axle air tank, while maintaining the maximum

engine RPM output until the air tank pressure is equal or greater than 8.3 bar. This facilitates in achieving an ideal stoichiometric air-fuel ratio indicating an improved vehicle performance with minimal fuel requirement.
According to an embodiment, the present disclosure discloses an improved air-brake system configured to draw atmospheric air to fill the front axle air tank and the rear axle air tank by an automatic engine acceleration to an ideal RPM output level at a vehicle standstill position without driver intervention. Further, in an embodiment, the disclosed air-brake system for a vehicle having an internal combustion engine includes the front axle air tank, the rear axle air tank, a compressor for supplying compressed air to the front axle air tank and the rear axle air tank, a vehicle speed sensor configured for generating a vehicle speed signal indicative of a vehicle speed, air pressure sensors in communication with the front axle air tank and the rear axle air tank respectively, for measuring air tank pressure therein and generating air pressure signals. Further, the air-brake system includes a control module. The control module, in response to the vehicle speed signal indicative of a vehicle predetermined speed and at least one air pressure signal indicative of an air tank pressure value below a predetermined air tank pressure value, is configured to accelerate the engine until an engine RPM level corresponds to a predetermined threshold engine RPM level and actuate the compressor upon the engine acceleration to supply the compressed air to the front axle air tank and the rear axle air tank until the air tank pressure therein corresponds to the predetermined air tank pressure value. In an embodiment, the predetermined air tank pressure value is equal or greater than 8.3 bar. The predetermined threshold engine RPM level corresponds to an engine maximum RPM threshold level. The engine upon attaining the predetermined threshold RPM level remains at the engine maximum RPM threshold level until the air tank pressure corresponds to the predetermined air tank pressure value and gradually comes to normal RPM value. In an embodiment, the vehicle predetermined speed corresponds to a standstill speed at which the vehicle enters the vehicle standstill position.

Reference will now be made to the exemplary embodiments of the disclosure, as illustrated in the accompanying drawings. Wherever possible, same numerals have been used to refer to the same or like parts. The following paragraphs describe the present disclosure with reference to Figs. 1-3. It is to be noted that the system and method may be employed in any vehicle including but not limited to a passenger vehicle, a utility vehicle, commercial vehicles, and any other vehicle with an exhaust system.
A vehicle including a prime mover such as, an IC engine, braking systems in the form of a pneumatically-driven arrangement (or “air brake arrangement”) are required for slowing and stopping vehicles. The air brake systems rely on compressors to supply pressurized air to air tanks which in turn supply air, under pressure, to the brake system. Due to wear or faulty fittings of the components, unsuitable seals, corrosion, loose fitting gasket or flexible hose of brake-lines, the air-brake systems can develop air leaks. Thus, due to occurrence of leakage, the air tank pressure goes below the predetermined air tank pressure value and thus the vehicle driver is unable to release brakes to drive the vehicle.
To facilitate in release of the park brake and vehicle start, an improved air-brake system is included in the vehicle, where the engine is automatically accelerated by the control unit and upon the engine acceleration, the compressor is actuated by the control unit to supply air-pressure to the air tank when air tank pressure is below the predetermined air tank pressure value.
Advantageously, according to an embodiment, the improved air-brake system facilitates in an automatic actuation of compressor to fill the front axle air tank and the rear axle air tank without involving driver intervention and at the same time maintains the air-fuel ratio at an ideal stoichiometric air-fuel ratio to achieve an improved vehicle performance with substantially reduced fuel consumption and emissions.

Figure 1 illustrates a schematic block diagram of an air-brake system (100) for a vehicle having an internal combustion engine (113), in accordance with an embodiment of the present disclosure. In an illustrated embodiment, the air-brake system (100) includes a front axle air tank (101a) and a rear axle air tank (101b), a compressor (105) for supplying compressed air to the front axle air tank (101a) and the rear axle air tank (101b). In an illustrated embodiment, an air dryer (103) is operatively connected to the compressor (105) to receive compressed air therefrom. The air-dryer (103) includes a drying or desiccant material through which the compressed air can flow to provide a clean and dry compressed to the air-supply unit (104). The drying or desiccant material is configured to remove moisture from compressed air. Further, the air-supply unit (104) is configured to supply the compressed air to the front axle air tank (101a) and the rear axle air tank (101b) for operating the system (100).
In an illustrated embodiment, a governor device (106) is mounted on the compressor (105) and configured for loading and unloading of the compressor (105). That is, once a desired pressure level in the front axle air tank (101a) and/or the rear axle air tank (101b) is equal or greater than a predetermined air tank pressure value, the compressor is unloaded and a signal is transmitted to a purge valve (not shown) carried within the air-dryer (103) which causes stored compressed air to backflow through the desiccant material at a controlled rate. In other words, compressing of air is intermittently cycled on and off automatically in response to the air tank pressure in the front axle air tank (101a) and the rear axle air tank (101b) by the governor device (106) and thereby regulates the pressure inside the front axle air tank (101a) and the rear axle air tank (101b) in which the compressed air having passed through the air supply unit (104) device is stored.
In the illustrated embodiment, the compressed air through the air-supply unit (104) is supplied through a flow-supply path divided into a first air-flow path conducted to a front axle air tank (101a) and a second air-flow path conducted to a rear axle tank (101b). Further, the system (100) includes a foot brake valve (110). The foot

brake valve (110), also referred as brake pedal, controls delivery of compressed air to front axle brake circuit (111) and a rear axle brake circuit (112) of the vehicle. And, as illustrated, upon actuation of the foot brake valve (110), a brake request signal is generated and the compressed air is conducted in a rear axle brake circuit (112) and a front axle brake circuit (111) through the rear-axle air tank (101a) and the front-axle air tank (101b), respectively for activating the air-brake system (100) and hence applying the vehicle brake.
Further, in an illustrated embodiment, the air-brake system (100) includes a vehicle speed sensor (107) configured for generating a vehicle speed signal indicative of a vehicle speed and air pressure sensors (108),(109) in communication with the front axle air tank (101a) and the rear axle air tank (101b), respectively, for measuring air tank pressure therein and generating air pressure signals. In an illustrated embodiment, the air pressure sensor (108) is communicatively connected to the rear axle air tank (101b) and configured to send air pressure signals to the control module (102). Further, the air pressure sensor (109) is communicatively connected to the front axle air tank (101a) and configured to send corresponding air pressure signals to the control module (102).
As illustrated, in response to the vehicle speed signal from the vehicle speed sensor (107) being indicative of a vehicle predetermined speed and at least one air pressure signal from the air-pressure sensors (108), (109) indicative of an air tank pressure value being below a predetermined air tank pressure value, the control module (102) is configured to accelerate the engine (113) until an engine RPM level corresponds to a predetermined threshold RPM level. And, at the same time upon engine acceleration, the control module (102) actuates the compressor (105) to supply the compressed air to the front axle air tank (101a) and the rear axle air tank (101b) until the air tank pressure corresponds to the predetermined air tank pressure value. Thus, as illustrated in an embodiment of the present disclosure, the control module (102) is configured for automatic engine acceleration and actuation of compressor to supply compressed air to the front axle air tank (101a) and the rear axle air tank

(101b) until the air tank pressure thereof corresponds to the predetermined air tank pressure value.
In an illustrated embodiment, the predetermined air tank pressure value is equal or greater than 8.3 bar. Upon attaining the predetermined threshold RPM level, the engine continues to remain at the engine maximum RPM threshold level until the air tank pressure value corresponds to the predetermined air tank pressure value. In an illustrated embodiment, after the air tank pressure of the front axle air tank (101a) and the rear axle air tank (101b) is equal or greater than the predetermined air tank pressure value, the control module (102) automatically decelerates the engine (113) to an initial RPM level at the predetermined vehicle speed. In an embodiment, the predetermined threshold engine RPM level corresponds to an engine maximum RPM threshold level in the predefined range of 2400 to 2800 RPM. As illustrated, an RPM sensor (114) is, mounted on a transmission output end of engine (113) and configured to collect revolution per minute (rpm) data from the engine (113) and transmits the same to the control module (102).
Further, in the illustrated embodiment, the vehicle predetermined speed corresponds to a standstill speed at which the vehicle enters the vehicle standstill position.
Figure.2 illustrates an engine performance curve (200), in accordance with an embodiment of the present disclosure. In an illustrated embodiment, the engine performance curve (200) is analyzed through the engine torque-power curve (201), (202) with a torque curve (201) and a power curve (202). These curves show the engine performance at vehicle standstill position, ignition ON, maximum torque output and at the engine maximum RPM level.
In an illustrated embodiment, the engine (113) operates at a predetermined torque based on the engine design for various engine RPMs/speeds. The engine speed/RPM is determined by an engine speed signal generated by the RPM sensor (114) (shown in Figure 2).

In the illustrated embodiment, the numbers utilized are representative and not meant to be limiting in the application of the present disclosure, but are only used to demonstrate one embodiment of the present disclosure. In an embodiment, for actuating the air-brake system (100) to drive the vehicle, it is desirable to provide a predetermined amount of torque output from the engine (113) upon the ignition ON and at the vehicle standstill position. In operation, the control module (102) of the vehicle is configured to accelerate the engine (113) to the predetermined engine RPM level upon the ignition ON and at the vehicle standstill position and when the air tank pressure is below the predetermined air tank pressure value. As the engine accelerate, the amount of torque increases to help the vehicle to accelerate more rapidly. At the same time, the control unit (102) actuates the compressor (105) to supply the compressed air to the front axle air tank (101a) and the rear axle air tank (101b) until the air tank pressure is equal or greater than a predetermined air tank pressure value.
Referring again to Figure 2, a predetermined torque output corresponding to a maximum torque output is determined at about 240 Nm of the torque curve (201). At maximum torque output of about 240 Nm, the engine RPM reaches in the range of about 3000 rpm to 4000 rpm. In an illustrated embodiment, the predetermined engine RPM indicative of the engine maximum output is defined in the range of about 3000 rpm to 4000 rpm. Thus, upon reaching the maximum torque output, the engine acceleration is controlled by the control module (102) such that the engine (113) is maintained at the engine maximum RPM output until the air tank pressure in the rear axle air tank and front axle air tank (101) is equal or greater than the predetermined air tank pressure of 8.3 bar. Thus, an ideal stoichiometric air-fuel ratio is achieved while maintaining the engine maximum RPM output by the control module (102) of the engine (113).It should be noted that for an internal combustion engine, the ideal stoichiometric air-fuel ratio is a mass ratio for complete fuel combustion. The ideal stoichiometric air-fuel ratio is approximately 14.7:1; i.e., 14.7 kilograms of air to 1 kilogram of fuel. In terms of volume, approximately 10,000 liters of air is required for 1 liter of fuel.

Further, in an embodiment, while the compressor (102) upon actuation continues to supply the compressed air to the front axle air tank (101a) and the rear axle air tank (101b), the engine (113) remains at maximum engine RPM output until the air tank pressure of the one or more tanks (101) is equal or greater than the predetermined air tank pressure value. In an embodiment, in the power curve (202), the engine (113) is configured to supply sufficient power at the engine maximum RPM output and when the torque is maximum such that the compressor (102) continues to supply the compressed air to the tanks until the air tank pressure corresponding to the predetermined air tank pressure value is achieved to permit release of the park brake and vehicle drivability. That is, as illustrated in the power curve (202), the engine’s maximum power supply is indicated at predefined power value of 280 Kw which may indicate that the air tank pressure of one or more air tanks (102) is equal or greater than the predetermined air tank pressure of 8.3 bar.
Figure.3 illustrates a flow-chart of a method (300) illustrating the operational sequence of the air-brake system (100) for the vehicle, in accordance with an embodiment of the present disclosure. In an embodiment, the air-brake system (100) for a vehicle having an internal combustion engine (113) is disclosed. In an illustrated embodiment, the air-brake system (100) includes a front axle air tank (101a) and a rear axle air tank (101b), a compressor (105) for supplying compressed air to the front axle air tank (101a) and the rear axle air tank (101b). Also, the air¬brake system (100) includes a vehicle speed sensor (107) configured for generating a vehicle speed signal indicative of a vehicle speed. Further, air- pressure sensors (108),(109) in communication with the front axle air tank (101a) and the rear axle air tank (101b), respectively, for measuring air tank pressure therein and generating air pressure signals.
With reference to an illustration, the method (300) starts at step 301. In an illustrated embodiment, once the ignition of the vehicle is in the ON condition, the vehicle speed sensor (107) determines the predetermined vehicle speed and generates the vehicle speed signals. The vehicle speed signal indicative of the vehicle

predetermined speed at which the vehicle enters the vehicle standstill position at the ignition ON condition is determined at step 302. At step 303, the air pressure signals being indicative of air tank pressure is continuously measured by the air pressure sensors (108), (109). At step 304, the air-pressure sensors (108), (109) determines if the air tank pressure is below the predetermined pressure value. Further, upon determining the air tank pressure below a predetermined air-pressure value, the control module (102) accelerates the engine (113) to the predetermined threshold RPM level. In an illustrated embodiment, the predetermined threshold engine RPM level corresponds to an engine maximum RPM threshold level in the predefined range of 2400 to 2800 RPM. Further, upon engine acceleration, the control module (102) actuates the compressor (105) to supply the compressed air to the front axle air tank (101a) and the rear axle air tank (101b) until the air tank pressure corresponds to the predetermined air tank pressure value, at step 307. If air tank pressure is determined to be equal or greater than the engine maximum RPM threshold level, the air-brake system (100) is actuated and release the parking brakes of the vehicle, at step 306. A parking brake of vehicle is released, at step 306. At step 308, the releasing of the parking brake, enables the driving of the vehicle. At step 309, the method (300) ends.
It should be imperative that the construction and configuration of the device, the system and any other elements or components described in the above detailed description should not be considered as a limitation with respect to the figures. Rather, variation to such structural configuration of the elements or components should be considered within the scope of the detailed description.
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."
In addition, where features or aspects of the disclosure are described in terms of Markush groups, those skilled in the art will recognize that the disclosure is also thereby described in terms of any individual member or subgroup of members of the Markush group.
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 Air-Brake System
101a Front axle air tank
101b Rear axle air tank
102 Control Module
103 Air Dryer
104 Air Supply Unit
105 Compressor
106 Governor
107 Vehicle Speed Sensor
108 Pressure Sensor
109 Pressure Sensor
110 Front Brake Valve
111 Front Axle Brake Circuit
112 Rear Axle Brake Circuit
113 Engine
114 RPM sensor
200 Engine RPM-Torque Graph
201 Engine Curve
202 Torque Curve
300 Method flow chart
301-309 Flow-chart steps

We Claim:
1. An air-brake system (100) for a vehicle having an internal combustion engine
(113), the system (100) comprising:
a front axle air tank (101a);
a rear axle air tank (101b);
a compressor (105) for supplying compressed air to the front axle air tank
(101a) and the rear axle air tank (101b);
a vehicle speed sensor (107) configured for generating a vehicle speed signal
indicative of a vehicle speed;
air pressure sensors (108),(109) in communication with the front axle air tank
(101a) and the rear axle air tank (101b), respectively, for measuring air tank
pressure therein and generating air pressure signals; and
a control module (102), in response to the vehicle speed signal indicative of a
vehicle predetermined speed and at least one air pressure signal indicative of
an air tank pressure value below a predetermined air tank pressure value,
configured to accelerate the engine (113) until an engine RPM level
corresponds to a predetermined threshold RPM level and actuate the
compressor (105) upon the engine acceleration to supply the compressed air
to the front axle air tank (101a) and the rear axle air tank (101b) until the air
tank pressure therein corresponds to the predetermined air tank pressure
value.
2. The system (100) as claimed in claim 1, wherein the predetermined air tank pressure value is equal or greater than 8.3 bar.
3. The system (100) as claimed in claim 1, wherein a predetermined threshold engine RPM level corresponds to an engine maximum RPM threshold level in the predefined range of 2400 to 2800 RPM.

4. The system (100) as claimed in claim 3, wherein the engine (113) upon attaining the predetermined threshold RPM level continue to remain at the engine maximum RPM threshold level until the air tank pressure corresponds to the predetermined air tank pressure value and gradually comes to normal RPM value.
5. The system (100) as claimed in claim 1, wherein the vehicle predetermined speed corresponds to a standstill speed at which the vehicle enters the vehicle standstill position.
6. A method of operating an air-brake system (100) for a vehicle having an internal combustion engine (113) and comprising a front axle air tank (101a) and a rear axle air tank (101b), a compressor (105) for supplying compressed air to the front axle air tank (101a) and a rear axle air tank (101b), a vehicle speed sensor (107) configured for generating a vehicle speed signal indicative of a vehicle speed, air pressure sensors (108),(109) in communication with the front axle air tank (101a) and the rear axle air tank (101b), respectively, for measuring air tank pressure therein and generating air pressure signals, the method comprising:
accelerating, by control unit, an engine (113) in response to a vehicle speed signal indicative of a vehicle predetermined speed and at least one air pressure signal indicative of an air tank pressure value below a predetermined air tank pressure value; and
actuating, by control unit, the compressor (105) upon the engine acceleration to deliver compressed air to the front axle air tank (101a) and the rear axle air tank (101b) until the air tank pressure therein corresponds to the predetermined air tank pressure value.
7. The method as claimed in claim 6, wherein the predetermined air pressure
value is equal or greater than 8.3 bar.

8. The method as claimed in claim 6, wherein a predetermined threshold engine RPM level corresponds to an engine maximum RPM threshold level.
9. The method as claimed in claim 6, wherein the engine (113) upon attaining the predetermined threshold RPM level remains at the engine maximum RPM threshold level until the air tank pressure corresponds to the predetermined air tank pressure value and gradually comes to normal RPM value.
10. The method as claimed in claim 6, wherein the vehicle predetermined speed corresponds to standstill speed at which the vehicle enters the vehicle standstill position.
11. The method as claimed in claim 6, wherein a predetermined threshold engine RPM level corresponds to an engine maximum RPM threshold level in the predefined range of 2400 to 2800 RPM.