FORM 2
THE PATENTS ACT 1970 (39 of 1970) & THE PATENTS RULES, 2003
COMPLETE SPECIFICATION
(See Section 10; rule 13)
TITLE OF THE INVENTION
Exhaust Brake with Backpressure Controlling Plate
APPLICANTS
TATA MOTORS LIMITED, an Indian company
having its registered office at Bombay House,
24 Homi Mody Street, Hutatma Chowk,
Mumbai 400 001 Maharashtra, India
INVENTORS
M.V. Shridhare
Prasad R Ambekar
An Indian Nationals
of TATA MOTORS LIMITED,
an Indian company having its registered office
at 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 performed

FIELD OF INVENTION
The present invention relates to exhaust system for vehicles and more particularly to an exhaust brake throttle valve with a backpressure controlling plate. The backpressure controlling plate is provided to develop higher backpressure at low revolutions per minute (RPM) and to reduce the overheating of service brake and lining temperatures.
BACKGROUND OF INVENTION
Exhaust brake is a means of slowing a diesel engine by closing off the exhaust path from the engine, causing the exhaust gases to be compressed in the exhaust manifold, and in the cylinder. The exhaust brakes are used as an auxiliary brake and are fitted in the exhaust pipe assembly of the vehicles. Such vehicles are generally powered by an internal combustion engine, often a diesel engine. Such engines displace exhaust under substantial pressure. If obstruction to displacement of exhaust is provided, the engine will operate less efficiently. Thus, blockage of exhaust flow tends to slow engine operation and act as a brake.
A variety of conventional exhaust brakes are known. In general these comprise valves that place a restriction, for example a restricted orifice, of fixed size into or out of alignment with exhaust gas flow. The restriction provides a smaller passageway for the exhaust gases, and thus inhibits exhaust flow. This creates a back pressure, providing the braking action. Generally these systems are designed so that the maximum back pressure provided is within safe operating limits for the engine, to reduce risk of engine damage.
The exhaust brake is used as an auxiliary brake which is fitted in the exhaust pipe assembly of the vehicle. When the exhaust brake is switched ON a throttle valve closes and hence the backpressure rises. This provides resistance to engine motion generating a braking torque. The engine always has backpressure limitation and it should not go beyond certain limit. The engine is converted as a power absorbing

machine. The existing exhaust brake has a throttle valve in it which is opened and closed using air cylinder. This throttle valve has fixed annular space inside the casting for the exhaust gas to pass through and therefore the backpressure generated is directly proportional to revolutions per minute (RPM). Also there is a high load on the brake system during downhill movement of the vehicle. This leads to high brake application resulting in lining wear and brake overheating. Hence there is a need to provide an exhaust brake system for vehicle to generate high backpressure at low RPM with varying area for exhaust gas flow.
OBJECT OF THE INVENTION
The primary objective of the present invention is to provide an exhaust brake with spring steel plate to develop higher backpressure at low RPM within the specification of engine requirements.
Another objective of the present invention is to provide an exhaust brake with spring steel plate to achieve higher backpressure by using a cost effective system to increase the braking efficiency.
Yet another object of the present invention is to reduce overheating of service brake and lining temperatures.
SUMMARY OF THE INVENTION
The embodiments herein provide an exhaust brake throttle valve with one more backpressure controlling plates. The backpressure controlling plate comprises a spring steel plate/stainless steel material mounted on throttle valve. The spring steel plate is mounted on two holes provided on the throttle valve of said exhaust brake such that it shuts the holes provided on the throttle valve for restricting exhaust gas passage through those vents or holes. The spring steel remains in its place at low revolutions per minute (RPM) and gets deflected as the RPM increase. Thus at low RPM higher backpressure is achieved and at high RPM the backpressure is

maintained within the limits of engine specification. The steel plate deflects at higher RPM to allow the air to flow through the vent or hole. An offset throttle valve is mounted on the shaft of the exhaust brake. The shaft will deflect from its place at higher exhaust flow due to pressure difference. Thus at lower RPM higher backpressure will be present as throttle valve will remain on its place and at higher RPM throttle valve will get deflected. The pressure difference between these two areas results in throttle valve movement as exhaust flow changes.
STATEMENT OF THE INVENTION
Accordingly the present invention discloses an exhaust brake system with back pressure controlling plate comprising
an exhaust brake throttle valve (1) provided with at least one back pressure controlling plate (3) configured for controlling the exhaust gas passage through the holes (2) provided on said exhaust brake throttle valve (1) to maintain the predetermined values of back pressure for safe operating of the engine.
The back pressure controlling plate (3) is of spring steel/stainless steel. The back pressure controlling plate (3) is mounted on said throttle valve (1) such that it is configured to cover the holes provided on said throttle valve for exhaust gas passage during lower rpm (revolution per minute) and opens said holes during higher rpm by its deflection for allowing the exhaust gas passage through said holes to maintain the back pressure within predetermined limits.
The exhaust valve is configured to be actuated by operating the exhaust brake pedal to offer resistance to engine motion generating brake torque.
The back pressure controlling plate (3) is configured to be retained in a predetermined annular angle providing a fixed gap and by closing the holes of said exhaust brake throttle valve (1) to develop a predetermined value of the back pressure. The throttle valve provided is an offset throttle valve.

BRIEF DESCRIPTION OF THE DRAWINGS
FIG. 1 shows a perspective view of a typical exhaust brake valve model.
FIG. 2 shows a perspective view of the exhaust valve with spring steel plate covering
throttle valve holes at low RPM, according to present invention.
FIG. 3 shows a perspective view of the exhaust valve with spring steel plate
deflected at high RPM thus controlling backpressure at higher RPM, according to
present invention.
Plate
FIG. 4 shows a cross sectional view of the exhaust valve with a spring steel plate
deflected during higher exhaust flow, according to present invention.
FIG. 5 shows a graph illustrating backpressure V/s RPM curve using existing
exhaust brake.
DETAILED DESCRIPTION OF THE INVENTION
The embodiments herein provide an exhaust brake throttle valve with one more backpressure controlling plates. The backpressure controlling plate comprises a spring steel plate/stainless steel material mounted on throttle valve. The backpressure controlling plate is provided to develop higher backpressure at low revolutions per minute (RPM) and to reduce the overheating of service brake and lining temperatures.
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.
A perspective view of a typical exhaust brake valve model is as shown in FIG. 1. The throttle valve (1) includes a pair of holes (2). When the exhaust brake pedal is operated the throttle valve rotates to block the exhaust gas flow. The fixed area of the

gas flow is equal to the angular gap and the holes on the throttle valve. This provides resistance to engine motion generating a braking torque. The engine always has backpressure limitation and it should not go beyond certain limit. Hence an exhaust valve is provided with spring steel plate to cover the throttle valve holes at low RPM, as shown in FIG. 2. Accordingly, the fixed area of gas flow is equal to the annular gap and closed holes till development of required back pressure. The spring steel plate (3) restricts its movement at lower exhaust flow hence a greater backpressure is obtained. At higher exhaust flow the spring steel plate deflects and allows the air to escape through this hole, as shown in FIG. 3. The spring steel plate is mounted on two holes/vents provided on the throttle valve of said exhaust brake. The spring steel remains in its place at low revolutions per minute (RPM) and gets deflected as the RPM increase. Thus at low RPM higher backpressure is achieved and at high RPM the backpressure is maintained within the limits of engine specification. The steel plate deflects at higher RPM to allow the air to flow through the vent or hole. An offset throttle valve is mounted on the shaft of the exhaust brake. The shaft will deflect from its place at higher exhaust flow due to pressure difference. Thus at lower RPM higher backpressure will be present as throttle valve will remain on its place and at higher RPM throttle valve will get deflected. The pressure difference between these two areas results in throttle valve movement as exhaust flow changes. The cross sectional view of the exhaust valve with a spring steel plate deflected during higher exhaust flow, is as shown in FIG. 4. FIG. 5 shows a graph illustrating backpressure V/s RPM curve using existing exhaust brake.
ADVANTAGE:
• Higher braking effort at high gears.
• Minimized utilization of service brakes.
• Higher average speed during downhill vehicle movement.
• Higher lining life and reduced brake temperatures.
• Higher braking power at low RPM.

• Low cost involved & easy to manufacture.
The foregoing description is a specific embodiment of the present invention. It should be appreciated that this embodiment is described for purpose of illustration only, and that numerous alterations and modifications may be practiced by those skilled in the art without departing from the spirit and scope of the invention. It is intended that all such modifications and alterations be included insofar as they come within the scope of the invention as claimed or the equivalents thereof.

We claim:
1. An exhaust brake system with back pressure controlling plate comprising
an exhaust brake throttle valve (1) provided with at least one back pressure controlling plate (3) configured for controlling the exhaust gas passage through the holes (2) provided on said exhaust brake throttle valve (1) to maintain the predetermined values of back pressure for safe operating of the engine.
2. The exhaust brake system as claimed in claim 1 wherein said back pressure controlling plate (3) is of spring steel/stainless steel.
3. The exhaust brake system as claimed in claim 1 wherein said back pressure controlling plate (3) is mounted on said throttle valve (1) such that it is configured to cover the holes provided on said throttle valve for exhaust gas passage during lower rpm (revolution per minute) and opens said holes during higher rpm by its deflection for allowing the exhaust gas passage through said holes to maintain the back pressure within predetermined limits.
4. The exhaust brake system as claimed in claim 1 wherein said exhaust valve is configured to be actuated by operating the exhaust brake pedal to offer resistance to engine motion generating brake torque.
5. The exhaust brake system as claimed in claim 1 wherein said back pressure controlling plate (3) is configured to be retained in a predetermined annular angle providing a fixed gap and by closing the holes of said exhaust brake throttle valve (1) to develop a predetermined value of the back pressure.
6. The exhaust brake system as claimed in claim 1 wherein said throttle valve provided is an offset throttle valve.

7. An exhaust brake system with back pressure controlling plate substantially as claimed is with referenced to the accompanying drawings.