FORM 2
THE PATENTS ACT 1970
(39 of 1970)
&
THE PATENTS RULES, 2003
COMPLETE SPECIFICATION
(See Section 10; rule 13)


TITLE OF INVENTION An Improved Twin Cylinder Indirect Ignition Uneven Firing Engine
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
Mr. Dattatraya R. Katkar, Mr.Deepak S. Kulkarni
And Mr. Nilesh A. Lende
All are 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 to be performed


FIELD OF INVENTION
This invention relates to I.C. engines and more particularly this relates to twin cylinder indirect ignition (in Pre-combustion chamber) uneven firing Kerosene engine.
BACKGROUND OF INVENTION
Kerosene and similar fuels have higher distillation temperatures than gasoline. In the prior art, a Kerosene engine is started with gasoline and gasoline is mixed with variable quantities with Kerosene to facilitate the smooth operation until the engine reaches the temperature that the kerosene alone can vaporize and can be ignited by spark plug. In a diesel engine, the air temperature is raised high by extra ordinary compression ratio and then fuel is injected and burned; so it is ignited without spark plug.
In many areas of the world kerosene fuel is preferred because it is cheaper, or readily available. It is therefore desirable to provide an engine which can be operated solely on kerosene, without the use of gasoline.
It is generally known in internal combustion engine that in any kinds of fuel one effective means for increasing thermal efficiency is to improve fuel consumption and a better power output is obtained by increasing the compression ratio of engine. However, it is known that a very high compression ratio results in an occurrence of knocking. Kerosene has a lower octane number than gasoline; a kerosene internal combustion engine tends to cause knocking as compared with gasoline internal combustion engine. So in general people make kerosene engine with low compression ratio for avoiding the knocking.
Knocking phenomenon is caused by rapid and spontaneous ignition of un-burnt end gas.

OBJECTS OF INVENTION
The main object of this invention is to provide a twin cylinder indirect ignition uneven firing kerosene engine.
Yet another object of this invention is to provide a twin cylinder indirect ignition uneven firing kerosene engine which is able to give the optimum performance.
Yet another object of this invention is to provide a twin cylinder indirect ignition uneven firing engine with pre-combustion chamber which can work with high compression ratio.
Yet another object of this invention is to provide a twin cylinder indirect ignition uneven firing water cooled engine.
Yet another object of this invention is to provide a twin cylinder indirect ignition uneven firing engine with intake and exhaust ports and inlet and exhaust manifolds provided on either side of cylinder head.
Yet another object of this invention is to provide a twin cylinder indirect ignition uneven firing engine which can start on kerosene & run on kerosene.
STATEMENT OF INVENTION
The novel twin cylinder indirect ignition uneven firing kerosene engine comprises a crank train with its housing, Pre-combustion chamber in cylinder head, Main Combustion chamber, Valve train and its housing, Manifolds and Flywheel, wherein said crank train housing houses crankshaft at its bottom, pistons with rings are connected to the crankshaft by a connecting rod, flywheel having sensor teeth is mounted on one end of said crankshaft, said combustion chamber is provided in the cylinder head, intake and exhaust ports are provided on opposite sides of said

cylinder head, intake and exhaust manifolds are connected to said intake and exhaust ports respectively, at least two spark plugs are provided on cylinder head. i.e. a final part of the mixture to be burned to the flame propagation for controlling the knocking
1. Increase the flame speed to raise a combustion speed.
2. Shortening the distance of flam propagation.
Both requirements can be achieved by indirect ignition in pre-combustion chamber for anti-knocking property.
Accordingly, the present invention relates to an improved twin cylinder indirect ignition uneven firing engine comprising: at least c>ne pre-combustion chamber coupled to one combustion chamber, wherein said pre-combustion chamber is of hemispherical or cylindrical shape to maintain the compression ratio towards higher side and to use various fuels by changing compression ratio and said pre-combustion chamber has closed flat surface at one end and at least one communication hole on the other side and is also provided with at least one spark plug.
The size and number of the communicating holes vary depending on application and requirement of engine. Also, size of said pre-combustion chamber varies according to swept volume of the engine. The shape of said comrnunication hole is cylindrical/ oval to achieve desired performance.
In a preferred embodiment, more than one spark plug is provided for better emissions control and less fuel consumption.
The head is kept same and crank case is changed for longer stroke length to achieve higher torque at low end side and the size of said pre-combustion chamber varies according to fuel properties.

The material of said pre-combustion chamber is the materials which can withstand high compression pressure in high temperature zone such as high carburized steel or aluminum alloys or cast iron or ceramic.
At least one glow plug for heating the pre combustion chamber is provided for smooth cold staring of engine.
The angle of said communication hole varies from 20° to 35° according to emission requirements and quality of fuel used and the angle of spark plug varies from 15° to 90° depending upon the packaging constrain in engine.
The pre-combustion chamber inlet is assembled with the head with help of thread/ fastening arrangement or any joining process to withstand working requirements in high temperature zone.
BRIEF DESCRIPTION DRAWINGS
Now innovation will be described with accomplishing drawings.
Fig. 1 shows an assembly of novel twin cylinder indirect ignition uneven firing
engine.
Fig. 2 shows Working principle of twin cylinder uneven firing engine.
Fig. 3 shows piston along with the combustion system used in this invention.
Fig. 4 shows an isometric view and cross sectional front view of pre combustion
chamber insert with single communication hole.
Fig 5 shows an isometric view and cross sectional front view of the Pre-combustion
chamber insert with multiple holes.
BRIEF DESCRIPTION OF INVENTION
The novel twin cylinder indirect ignition uneven firing Kerosene engine in accordance with this invention basically comprises of Crank train with its housing,

Pre- Combustion chambers, Main Combustion chambers, Valve train and its housing, Manifolds and Flywheel, said crank train primarily comprises of crankshaft, connecting rod, Piston with piston rings. Said valve train housing comprises cylinder head, inlet and exhaust ports and combustion chambers.
Wherein said crank train housing houses crankshaft at its bottom. Piston with rings is connected to the crankshaft by a connecting rod. Flywheel with low inertia mounted on the crankshaft end.
Pre-combustion chamber is provided in the cylinder head. Intake and exhaust valves are actuated by an overhead camshaft. Intake and exhaust ports are provided on the opposite sides of the cylinder head. Intake and exhaust manifolds connect ports to intake and exhaust system respectively. Spark plugs are provided in the pre combustion chambers of the cylinder head.
An object of present invention to provide a knocking free combustion of I. C. Engine with kerosene, comprising: a cylinder head; a piston; a main combustion chamber defined by a lower surface of the cylinder head and an upper surface of the piston with cavity; pre-combustion chamber defined within the cylinder head cylinder and spaced from the main combustion chamber by a partition insert with hole.
Carburetor is used for atomizing the kerosene in air and feeding an air fuel mixture of theoretical or richer fuel ratio to the main combustion chamber; a suction port and an exhaust port adapted to be opened & closed by suction valve and an exhaust valve, respectively. A spark plug is provided in the pre-combustion chamber and an insert with hole forms the communication between pre combustion chamber and main combustion chamber. With this arrangement, a compressed inflammable air-fuel mixture having a theoretical or richer fuel ratio which has been drawn into main combustion chamber is injected in to the pre- combustion chamber and is burned by spark ignition. The burnt gas expanded under high temperature is injected into the main combustion chamber through the hole provided on pre-combustion chamber

insert to spread from the upper surface of the piston located near the top dead center over a wide region. By this method the mixture in the main combustion chamber can be burnt rapidly with a short distance of flame propagation and occurrence of knocking can be suppressed to a possible extent at higher compression ratio for providing a high power kerosene engine. Due to higher compression ratio engine can be started on kerosene without using gasoline. Thus, in cooperation with use of inexpensive kerosene fuel, a high power out put engine can be obtained at extremely low cost.
In addition to this, we can develop existing diesel engine by reducing some expensive components for Kerosene fuel application.
DETAILED DESCRIPTION OF INVENTION
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
Referring to fig. no.l, one over head valve engine is assembled by cylinder head (A) & crankcase block (B) with gasket (C) in between them. Crankcase block (B) includes a piston (3) which is slidable in the cylinder (4) defined therein. Piston (3) is connected to crankshaft (6) through connecting rod (5). Crankshaft (6) is fitted in the crankcase block (B) and revolves in main bearing (7). Reference numeral (8) shows water cooling jackets of crankcase block (B). Piston (3) is having a cavity on it's top and it plays a major roll for forming a main combustion chamber.
Cylinder head (A) assembled with over head cam shaft (9) and valve train (10). Pre-combustion chamber insert (2) is fitted in cylinder head (A) from its lower surface with the help of self locking ball mechanism. Spark plug (1) is fastened in cylinder head (A) and its electrode is opened in the cavity of cylinder head (A) and it is closed by Pre-combustion chamber insert (2). Pre-combustion chamber is formed

between insert (2), cavity inside the cylinder head (A) and some part of spark plug (1) bore. Main combustion chamber is located bellow pre-combustion chamber. Main combustion chamber is formed between top surface of said piston (3) with cavity and bottom portion of cylinder head (A). Pre-combustion chamber and main combustion chamber is separated by pre-combustion chamber insert (2). Reference numerals (11) and (12) indicate the cooling water gallery and oil gallery for cylinder head (A) respectively.
In fig.no.3 close view of combustion chambers is shown. Pre-combustion chamber is cylindrically shaped with spherical upper surface. Pre-combustion chamber (P) is extended in spark plug bore (A) and closed by spark plug (1). (C) is the hole provided in the pre-combustion chamber insert for communication between pre-combustion chamber P and Main combustion (M).
When the engine is under operation, in suction stroke air fuel mixture is sucked in the main combustion chamber (M) and at the time of compression, air fuel mixture injected in pre-combustion chamber (P) through communication hole (C) provided in the pre-combustion chamber insert. At the end of compression, spark is generated through spark plug (1) and air fuel mixture is initially ignited in spark plug bore (A') and then flame is propagated to the whole air fuel mixture existing inside the pre-combustion chamber (P). The burnt gas is expanded by temperature rise, starting to be injected through communication hole (C) into main combustion chamber (M). The injected high temperature gas is speared on all over the entire area of main combustion chamber (M).The combustion is extremely rapidly completed at an extreme speed. The flame from the pre-combustion chamber (P) is injected into main combustion chamber (M) through communication hole (C) so that the flame is rapidly propagated over the entire area in the main combustion chamber (M). The flame speed is increased to raise the combustion speed and distance of flame propagation is reduced, which are primary factors for suppressing the knocking.

Shown Fig.no.2 is self explanatory about the principle of twin cylinder uneven firing of Kerosene engine. 4-strokes of the cycle of both cylinders has been plotted for understanding the behavior of uneven firing. At least the wave form is plotted for understanding the consecutive two power strokes occurred after 360° gap of crank rotation.
In fig4 detailed views of pre-combustion chamber insert is shown. (C) is the communication single through hole with it's opening shape. The shape of hole and the angle (a)) is specific embodiment of present invention. Reference numeral (13) indicates the self locking ball mechanism of the pre-combustion chamber insert.
Figure5 is another kind of design for pre combustion chamber insert. In which a plurality of holes (C) are provided for the air fuel mixture feeding and flame propagation. Such kind of design helps in ignition timing advancing with respect to engine speed increase situation and transient operations of engine. All holes are located radially and open inside the inner surface of the insert. So in flame propagation the high temperature gases sprayed all entire area of main combustion chamber within very less time. The angle (Ω) is important according to present invention.
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 improved twin cylinder indirect ignition uneven firing engine comprising:
- at least one pre-combustion chamber coupled to one combustion chamber,
- wherein said pre-combustion chamber is of hemispherical or cylindrical shape to maintain the compression ratio towards higher side and to use various fuels by changing compression ratio and said pre-combustion chamber has closed flat surface at one end and at least one communication hole on the other side and is also provided with at least one spark plug.

2. Improved twin cylinder indirect ignition uneven firing engine as claimed in claim 1, wherein size and number of said holes vary depending on application and requirement of engine.
3. Improved twin cylinder indirect ignition uneven firing engine as claimed in claim 1, wherein more than one spark plug is provided for better emissions control and less fuel consumption.
4. Improved twin cylinder indirect ignition uneven firing engine as claimed in claim 1, wherein size of said pre-combustion chamber varies according to swept volume of the engine.
5. Improved twin cylinder indirect ignition uneven firing engine as claimed in claim 1, wherein head is kept same and crank case is changed for longer stroke length to achieve higher torque at low end side,
6. Improved twin cylinder indirect ignition uneven firing engine as claimed in claim 1, wherein size of said pre-combustion chamber varies according to fuel properties.
7. Improved twin cylinder indirect ignition uneven firing engine as claimed in claim 1, wherein material of said pre-combustion chamber is the materials which can

withstand high compression pressure in high temperature zone such as high carburized steel of aluminum alloys or cast iron or ceramic.
8. Improved twin cylinder indirect ignition uneven firing engine as claimed in claim 1, wherein at least one glow plug for heating the pre combustion chamber is provided for smooth cold staring of engine.
9. Improved twin cylinder indirect ignition uneven firing engine as claimed in claim 1, wherein angle of said communication hole varies from 20 to 35° according to emission requirements and quality of fuel used.
10. Improved twin cylinder indirect ignition uneven firing engine as claimed in claim 1, wherein angle of spark plug varies from 15° to 90° depending upon the packaging constrain in engine.
11. Improved twin cylinder indirect ignition uneven firing engine as claimed in claim 1, wherein shape of said communication hole is cylindrical/ oval to achieve desired performance.
12. Improved twin cylinder indirect ignition uneven firing engine as claimed in claim 1, wherein said pre-combustion chamber inlet is assembled with the head with help of thread/ fastening arrangement or any joining process to withstand working requirements in high temperature zone.
13. An improved twin cylinder indirect ignition uneven firing engine as herein
above described and shown in accompanying drawings.
Dated this 26th day of March 2009

(Karuna Goleria)
of De PENNING & De PENNING
TATA Motors Limited By their Agent & Attorney