Title of Invention	INTERNAL COMBUSTION ENGINE WITH IMPROVED COMBUSTION CHARACTERISTICS
Abstract	An improved Internal Combustion Engine working on four stroke principle having two valves per cylinder, for efficient burning of lean air fuel mixture used in engines wherein the diameter of cylinder bore ranges between 45 mm and 70 mm characterized in that said Internal Combustion Engine comprises a pair of spark plugs, namely a first spark plug (21) and a second spark plug (22), a cylinder head (25), a sleeve (23). A pair of sealing means (24, 24a), fixing means (26) and a sleeve cap (27); said first and a second spark plugs (21 and 22) being fitted to said cylinder head (25) and capable of igniting air fuel mixture at predetermined instant; said second spark plug (22) being housed within said sleeve (23) located within timing chain cavity; said sleeve (23) being detachably push fitted to said cylinder head (25) and held in position by said fixing means (26), said sealing means (24, 24a) being adapted between said cylinder head (25) and the outer periphery of said sleeve (23) and said sleeve cap (27) being fitted on said cylinder head (25)

Title of Invention

INTERNAL COMBUSTION ENGINE WITH IMPROVED COMBUSTION CHARACTERISTICS

Abstract

An improved Internal Combustion Engine working on four stroke principle having two valves per cylinder, for efficient burning of lean air fuel mixture used in engines wherein the diameter of cylinder bore ranges between 45 mm and 70 mm characterized in that said Internal Combustion Engine comprises a pair of spark plugs, namely a first spark plug (21) and a second spark plug (22), a cylinder head (25), a sleeve (23). A pair of sealing means (24, 24a), fixing means (26) and a sleeve cap (27); said first and a second spark plugs (21 and 22) being fitted to said cylinder head (25) and capable of igniting air fuel mixture at predetermined instant; said second spark plug (22) being housed within said sleeve (23) located within timing chain cavity; said sleeve (23) being detachably push fitted to said cylinder head (25) and held in position by said fixing means (26), said sealing means (24, 24a) being adapted between said cylinder head (25) and the outer periphery of said sleeve (23) and said sleeve cap (27) being fitted on said cylinder head (25)

Full Text	FORM - 2 THE PATENTS ACT, 1970 ( 39 of 1970 ) PROVISIONAL / COMPLETE SPECIFICATION SECTION 10 TITLE APPLICANT An improved internal contribution BAJAJ AUTO LIMITED, an Indian Limited Company, of Akurdi, Pune 411 035, Maharashtra, India The following specification particularly describes the nature of the invention and the manner in which it is to be performed This invention relates to improvement in the combustion characteristics of a two valve per cylinder internal combustion engine working on four stroke principle. This invention particularly relates to small displacement engines of swept cylinder volume ranging from 75 cc to 225 cc and cylinder bore diameter 45 mm to 70 mm, preferably in the range of 100 cc to 200 cc, employed as prime movers for operation of 2 and 3 wheeled vehicles or other motorized vehicles. For the simplicity of explanation, such engines are termed as 'engines' in the subsequent paragraphs in this specification. These engines are provided with two valves namely inlet valve and exhaust valve. These valves open in a cavity in the cylinder head conventionally known as combustion chamber. The valves are actuated by rocker arms. The actuation of the rocker arms is by a cam that is driven by the crankshaft through a timing chain and driving and driven sprockets. Such engines are provided with one spark plug per cylinder. The spark plug is an essential part of the engine that develops a spark inside the combustion chamber of cylinder head that ignites the air-fuel mixture and : 2 : develops power. This type of arrangement is well known to the prior art and it is not essential to explain the same in detail. The location of the spark plug inside the combustion chamber is in between the two valves and opposite to the location of the chain and driven sprocket arrangement. The utility of a spark plug in such engines is explained in greater details in the following paragraph. The air fuel mixture commonly referred to as a 'charge' is in the compressed condition at the near end of the compression stroke (also known as Top Dead Centre or TDC). This charge may, as a result of the entry geometry of the intake valve and other factors have swirling and tumbling motion inside the combustion chamber. Due to the swirling and tumbling motion, the flame inside the combustion chamber propagates in a desired manner and the peak of the developed power occurs at an instant as required by the design. In order to achieve optimum performance, the location of spark plug top, velocity of the charge, the direction of swirl and tumble are some of the important parameters. There are various methods known to improve the engine performance by optimizing the combustion characteristics. Some of these are improved ignition timing, improved combustion chamber design, improved valve timing and valve angles etc. 3 One of the disadvantages associated with the arrangement explained above is that since there is only one spark plug, the process of combustion from initiation of the spark to its completion takes a comparatively longer duration. At higher speeds of revolution, this available time is may be insufficient and result in incomplete combustion and consequent loss of power, fuel wastage and increase in emissions. A further disadvantages of the prior art is the need of a richer or more mixture of fuel and air in the charge to achieve better driveability. Yet another disadvantage of the prior art is that the flame is not able to propagate adequately in the combustion chamber if the mixture is lean which results in inadequate power. In order to avoid at least some of the above note difficulties and provide for improved combustion characteristics through rapid completion of the combustion even with a lean air fuel mixture, we have inventetd an engine wherein there are two spark plugs provided for generating sparks at two predetermined locations at the same time. These spark plugs are located in the cylinder head one on timing chain side and the other plug : 4 : opposite to the timing chain side. Thus, the twin spark plug arrangement enables the engine to run efficiently which results in decreased emission, decreased fuel consumption and good driveability. Use of two spark plugs in an engine with three valves and of relatively larger bore diameter (more than 70 mm) is known, eg. as described in US Patent No.4534322 Al. In the engines with three valves, the space restriction in the cylinder head does not provide an optimum place for the spark plug (ideally to be mounted centrally) and it is necessary to adopt two spark plugs to achieve proper combustion even with the normal mixture ratios. Use of two spark plugs for an engine with only two valves is therefore not normally necessitated from space constraints. Furthermore, as the bore size (and therefore the swept volume) of a cylinder increases, the flame propagation distance increases and therefore the use of twin spark plugs becomes a consideration. In contrast it is counterintuitive to consider the use of twins sparkplugs in a small bore cylinder application as the flame propagation distance is not normally an issue that arises in conventional engines. The cavity in which the timing chain is located opens in the crankcase that is filled with oil for lubrication of moving parts. The chain : 5 : while driving the driven sprocket carries oil with it for lubrication and if the opening for spark plug is provided in this cavity the lubricating oil spreads over the spark plug and affects its function. In order to have the spark plug on the timing chain side and to prevent the above disadvantage we have further invented an arrangement wherein the plug is located on the same side of the timing chain by providing a replaceable sleeve, which is push fitted in the cavity, which encompasses the spark plug. In contrast, US 453 432 teaches the use of a sleeve; which is threaded into cylinder head. Fixation of the sleeve by the screwing leads to two difficulties, one of maintaining concentricity of the sleeve with respect to the spark plug and possible damage to the O ring. This has been solved by fixing the replaceable sleeve by push fitting instead of using threads. This arrangement will now be explained in detail with reference to accompanying figures wherein Figure 1 shows the cross-section of the prior art engine with one Spark plug. 6 Figure 2 shows the cross-section of the improved engine with two spark plugs. The invented two valve per cylinder engine with improved combustion characteristics for efficient air fuel mixture burning, essentially comprises of a pair of spark plugs (21 & 22), sleeve (23), O rings (24 and 24a), cylinder head (25), circlip (26) and sleeve cap (27). With reference to figure 1, the spark plug (1) is located in the cylinder head (2) opposite to the timing chain (7) side. The spark plug (1) is fixed to the cylinder head (2) to reach in combustion chamber (3). The inlet (4) and exhaust (5) valves also open in the combustion chamber (3). The cylinder head (2) is having a cavity (6) through which the timing chain (7) drives the driven sprocket (8). The driven sprocket (8) further drives the cam shaft (9) which actuate the valves (4) and (5) through rocker arms (not shown). When the engine runs, the timing chain carries oil from the crankcase (not shown) for the lubrication of the driven sprocket (8) and the cavity (6) is splashed with oil. Any opening made on this side exposes the passage of the oil to outside and the oil starts leaking. 7 When the charge is compressed at the end of the compression stroke in the combustion chamber (3), a spark is initiated by the spark plug (1), and the flame propagates from the tip (la) of the spark plug (1). The combustion of the charge takes place in the combustion chamber (3) to produce power. It is clear from the figure that the flame has to propagate from the tip (la) and ignite the entire mixture in the combustion chamber (3) that needs comparatively more time, particularly at higher speeds of the engine. This results in incomplete combustion and consequent loss of power, fuel wastage, and increase in emissions and poor part throttle efficiency. With reference to figure 2, the two valve per cylinder engine with improved combustion characteristics for lean air fuel mixture burning has two spark plugs (21 & 22) which are located in the cylinder head (25). These spark plugs are located in the cylinder head (25) diametrically opposite to each other. One of the spark plug (21) is located in the same location as in the prior art and the other spark plug (22) is located on the same side as the timing chain (7). The sleeve (23) is detachably push fitted in the cylindrical portion of the cylinder head (25). Between the outer periphery of the sleeve and the inner periphery of the cylindrical 8 portion, two 'O' rings (24 and 24a) are provided. The sleeve (23) is retained in position by means of a screw (26) and this arrangement is closed by a sleeve cap (27) snugly fitted on to the sleeve (23) with its outer lip covering the opening in the cylinder head (25), which provides protection from entry of dust, water etc. The sleeve cap (27) is manufactured by molding of non-metallic materials like nylon, PVC, rubber etc. The energy for spark, in case of twin spark plug engine is provided through the same system as single spark plug where the conventional components like H.T. coil, H.T. cable, etc. are provided in duplicate. By providing two spark plugs, the initiation of the spark starts at two places, ie. tips (21a & 22a) in the combustion chamber. These places are diametrically opposite to each other. Due to this, the combustion is completed in a comparatively shorter duration of time leading to reduction in emission and improved fuel consumption while maintaining the predetermined level of performance. This reduced time of achieving near complete combustion permits use of less amount of fuel air mixture or lean mixture without affecting the performance, especially at part throttle condition. 9 The applicants have developed a two valve, per cylinder 150 cc capacity engines with invented features of this application and the same has been evaluated. The table given below indicates the comparative test values of the engines with and without the invented feature. The emission values are as tested with statutorily applicable Indian Driving Cycle on Chassis dynamometer. Test results conducted on a 150 cc engine. No. Parameters Single sparkplugconfiguration Twin spark plug Configuration 1 CO mass emission (g/km) 1 0.6 2 HC mass Emission (g/km) 0.7 0.5 3 Nox mass emission (g/km) 0.5 0.5 4 Fuel consumption (km/1) 55 62 5 Max power (Ps) 11.7 12.5 10 It can be concluded from the above test values that there is a significant reduction in CO emissions from 1 g/km to 0.6 g/km and HC emissions from 0.7 g/km to 0.5 g/km. There is significant increase in fuel efficiency from 55 km/litre to 62 km/litre. The advantages mentioned above are obtained along with an improvement in peak power of the engine. As can be seen from the figures, when the engine runs, the oil carried by the timing chain (3) when splashed, falls on the outer periphery of the sleeve (23) and leads its way back to the crankcase without being exposed to outside and causing leakage. Usage of this sleeve (23) enables the use of a conventional "endless" type timing chain without any difficulty. The inner diameter of the sleeve (23) is so chosen that the spark plug can be removed without a spark plug spanner without any difficulty. This type of design is very critical since the same available in said engines is limited unlike in bigger engines. 11 The description and the figures provided in this patent application, indicate the location of spark plugs diametrically opposite to each other. However, depending upon the design requirements, it may be necessary to change the locations at predetermined angular positions. It will be appreciated that the invented engine with improved combustion characteristics for efficient air fuel mixture burning as described and illustrated in the drawing that it would be possible to modify and/or alter the various features thereof by person skilled in the art without deviating from the scope of the invention. The applicant intends to include those modifications and variations within the scope and the ambit of this invention. 12 WE CLAIM; 1. An improved Internal Combustion Engine working on four stroke principle, having two valves per cylinder, for efficient burning of lean air fuel mixture used in engines wherein the diameter of cylinder bore ranges between 45 mm and 70 mm characterized in that said Internal Combustion Engine comprises a pair of spark plugs, namely a first spark plug (21) and a second spark plug (22), a cylinder head (25), a sleeve (23), a pair of sealing means (24, 24a), fixing means (26) and a sleeve cap (27); said first and second spark plugs (21 and 22) being fitted to said cylinder head (25) and capable of igniting air fuel mixture at predetermined instant; said second spark plug (22) being housed within said sleeve (23) located within timing chain cavity; said sleeve (23) being detachably push fitted to said cylinder head (25) and held in position by said fixing means (26), said sealing means (24, 24a) being adapted between said cylinder head (25) and the outer periphery of said sleeve (23) and said sleeve cap (27) being fitted on said cylinder head (25). 2. An improved Internal Combustion Engine as claimed in Claim 1 wherein the said pair of spark plugs (21 and 22) are fitted subsequently diametrically opposite to each other. 13 3. An improved Internal Combustion Engine as claimed in Claims 1 and 2 wherein said fixing means (26) is a circlip or a screw. 4. An improved Internal Combustion Engine as claimed in Claims 1 and 2 wherein said pair of sealing means (24 and 24a) is an O ring or an oil seal. 5. An improved Internal Combustion Engine as claimed in any of the preceding claims wherein the sleeve cap (27) is made of resilient material, such as Nylon, PVC, rubber. 6. An improved Internal Combustion Engine working on four stroke principle, having two valves per cylinder, for efficient burning of lean air fuel mixture used in engines wherein the diameter of cylinder bore ranges between 45 mm and 70 mm characterized in that said Internal Combustion Engine comprises a spark plug (22), a cylinder head (25), a sleeve (23), a pair of sealing means (24, 24a), fixing means (26) and a sleeve cap (27); said spark plug (22) being fitted to said cylinder head (25) and capable of igniting air fuel mixture at predetermined instant; said spark plug (22) being housed within said sleeve (23) located within timing chain cavity; said sleeve (23) being detachably push fitted to said 14 cylinder head (25) and held in position by said fixing means (26), said sealing means (24, 24a) being adapted between said cylinder head (25) and the outer periphery of said sleeve (23), and said sleeve cap (27) being fitted on said cylinder head (25). 7. An improved single cylinder Internal Combustion Engine working on four stroke principle having two valves for efficient burning of lean air fuel mixture used in engines wherein the diameter of said cylinder bore ranges between 45 mm and 75 mm substantially as herein described and as illustrated in the drawings accompanying the Specification. Dated this 5th day of November 2004. M K CHAKRABARTI OF L S DAVAR & CO Agent for the applicant 15

Full Text

FORM - 2
THE PATENTS ACT, 1970
( 39 of 1970 )
PROVISIONAL / COMPLETE
SPECIFICATION
SECTION 10
TITLE

APPLICANT
An improved internal contribution

BAJAJ AUTO LIMITED, an Indian Limited Company, of Akurdi, Pune 411 035, Maharashtra, India
The following specification particularly describes the nature of the invention and the manner in which it is to be performed

This invention relates to improvement in the combustion characteristics of a two valve per cylinder internal combustion engine working on four stroke principle. This invention particularly relates to small displacement engines of swept cylinder volume ranging from 75 cc to 225 cc and cylinder bore diameter 45 mm to 70 mm, preferably in the range of 100 cc to 200 cc, employed as prime movers for operation of 2 and 3 wheeled vehicles or other motorized vehicles. For the simplicity of explanation, such engines are termed as 'engines' in the subsequent paragraphs in this specification.
These engines are provided with two valves namely inlet valve and exhaust valve. These valves open in a cavity in the cylinder head conventionally known as combustion chamber. The valves are actuated by rocker arms. The actuation of the rocker arms is by a cam that is driven by the crankshaft through a timing chain and driving and driven sprockets. Such engines are provided with one spark plug per cylinder. The spark plug is an essential part of the engine that develops a spark inside the combustion chamber of cylinder head that ignites the air-fuel mixture and
: 2 :

develops power. This type of arrangement is well known to the prior art and it is not essential to explain the same in detail. The location of the spark plug inside the combustion chamber is in between the two valves and opposite to the location of the chain and driven sprocket arrangement. The utility of a spark plug in such engines is explained in greater details in the following paragraph.
The air fuel mixture commonly referred to as a 'charge' is in the compressed condition at the near end of the compression stroke (also known as Top Dead Centre or TDC). This charge may, as a result of the entry geometry of the intake valve and other factors have swirling and tumbling motion inside the combustion chamber. Due to the swirling and tumbling motion, the flame inside the combustion chamber propagates in a desired manner and the peak of the developed power occurs at an instant as required by the design. In order to achieve optimum performance, the location of spark plug top, velocity of the charge, the direction of swirl and tumble are some of the important parameters. There are various methods known to improve the engine performance by optimizing the combustion characteristics. Some of these are improved ignition timing, improved combustion chamber design, improved valve timing and valve angles etc.
3

One of the disadvantages associated with the arrangement explained above is that since there is only one spark plug, the process of combustion from initiation of the spark to its completion takes a comparatively longer duration. At higher speeds of revolution, this available time is may be insufficient and result in incomplete combustion and consequent loss of power, fuel wastage and increase in emissions.
A further disadvantages of the prior art is the need of a richer or more mixture of fuel and air in the charge to achieve better driveability.
Yet another disadvantage of the prior art is that the flame is not able to propagate adequately in the combustion chamber if the mixture is lean which results in inadequate power.
In order to avoid at least some of the above note difficulties and provide for improved combustion characteristics through rapid completion of the combustion even with a lean air fuel mixture, we have inventetd an engine wherein there are two spark plugs provided for generating sparks at two predetermined locations at the same time. These spark plugs are located in the cylinder head one on timing chain side and the other plug
: 4 :

opposite to the timing chain side. Thus, the twin spark plug arrangement enables the engine to run efficiently which results in decreased emission, decreased fuel consumption and good driveability.
Use of two spark plugs in an engine with three valves and of relatively larger bore diameter (more than 70 mm) is known, eg. as described in US Patent No.4534322 Al. In the engines with three valves, the space restriction in the cylinder head does not provide an optimum place for the spark plug (ideally to be mounted centrally) and it is necessary to adopt two spark plugs to achieve proper combustion even with the normal mixture ratios. Use of two spark plugs for an engine with only two valves is therefore not normally necessitated from space constraints. Furthermore, as the bore size (and therefore the swept volume) of a cylinder increases, the flame propagation distance increases and therefore the use of twin spark plugs becomes a consideration. In contrast it is counterintuitive to consider the use of twins sparkplugs in a small bore cylinder application as the flame propagation distance is not normally an issue that arises in conventional engines.
The cavity in which the timing chain is located opens in the crankcase that is filled with oil for lubrication of moving parts. The chain
: 5 :

while driving the driven sprocket carries oil with it for lubrication and if the opening for spark plug is provided in this cavity the lubricating oil spreads over the spark plug and affects its function.
In order to have the spark plug on the timing chain side and to prevent the above disadvantage we have further invented an arrangement wherein the plug is located on the same side of the timing chain by providing a replaceable sleeve, which is push fitted in the cavity, which encompasses the spark plug. In contrast, US 453 432 teaches the use of a sleeve; which is threaded into cylinder head. Fixation of the sleeve by the screwing leads to two difficulties, one of maintaining concentricity of the sleeve with respect to the spark plug and possible damage to the O ring. This has been solved by fixing the replaceable sleeve by push fitting instead of using threads.
This arrangement will now be explained in detail with reference to accompanying figures wherein
Figure 1 shows the cross-section of the prior art engine with one Spark plug.
6

Figure 2 shows the cross-section of the improved engine with two spark plugs.
The invented two valve per cylinder engine with improved combustion characteristics for efficient air fuel mixture burning, essentially comprises of a pair of spark plugs (21 & 22), sleeve (23), O rings (24 and 24a), cylinder head (25), circlip (26) and sleeve cap (27).
With reference to figure 1, the spark plug (1) is located in the cylinder head (2) opposite to the timing chain (7) side. The spark plug (1) is fixed to the cylinder head (2) to reach in combustion chamber (3). The inlet (4) and exhaust (5) valves also open in the combustion chamber (3). The cylinder head (2) is having a cavity (6) through which the timing chain (7) drives the driven sprocket (8). The driven sprocket (8) further drives the cam shaft (9) which actuate the valves (4) and (5) through rocker arms (not shown). When the engine runs, the timing chain carries oil from the crankcase (not shown) for the lubrication of the driven sprocket (8) and the cavity (6) is splashed with oil. Any opening made on this side exposes the passage of the oil to outside and the oil starts leaking.
7

When the charge is compressed at the end of the compression stroke in the combustion chamber (3), a spark is initiated by the spark plug (1), and the flame propagates from the tip (la) of the spark plug (1). The combustion of the charge takes place in the combustion chamber (3) to produce power. It is clear from the figure that the flame has to propagate from the tip (la) and ignite the entire mixture in the combustion chamber (3) that needs comparatively more time, particularly at higher speeds of the engine. This results in incomplete combustion and consequent loss of power, fuel wastage, and increase in emissions and poor part throttle efficiency.
With reference to figure 2, the two valve per cylinder engine with improved combustion characteristics for lean air fuel mixture burning has two spark plugs (21 & 22) which are located in the cylinder head (25). These spark plugs are located in the cylinder head (25) diametrically opposite to each other. One of the spark plug (21) is located in the same location as in the prior art and the other spark plug (22) is located on the same side as the timing chain (7). The sleeve (23) is detachably push fitted in the cylindrical portion of the cylinder head (25). Between the outer periphery of the sleeve and the inner periphery of the cylindrical
8

portion, two 'O' rings (24 and 24a) are provided. The sleeve (23) is retained in position by means of a screw (26) and this arrangement is closed by a sleeve cap (27) snugly fitted on to the sleeve (23) with its outer lip covering the opening in the cylinder head (25), which provides protection from entry of dust, water etc. The sleeve cap (27) is manufactured by molding of non-metallic materials like nylon, PVC, rubber etc.
The energy for spark, in case of twin spark plug engine is provided through the same system as single spark plug where the conventional components like H.T. coil, H.T. cable, etc. are provided in duplicate.
By providing two spark plugs, the initiation of the spark starts at two places, ie. tips (21a & 22a) in the combustion chamber. These places are diametrically opposite to each other. Due to this, the combustion is completed in a comparatively shorter duration of time leading to reduction in emission and improved fuel consumption while maintaining the predetermined level of performance. This reduced time of achieving near complete combustion permits use of less amount of fuel air mixture or lean mixture without affecting the performance, especially at part throttle condition.
9

The applicants have developed a two valve, per cylinder 150 cc capacity engines with invented features of this application and the same has been evaluated. The table given below indicates the comparative test values of the engines with and without the invented feature. The emission values are as tested with statutorily applicable Indian Driving Cycle on Chassis dynamometer.
Test results conducted on a 150 cc engine.

No. Parameters Single sparkplugconfiguration Twin spark plug Configuration
1 CO mass emission (g/km) 1 0.6
2 HC mass Emission (g/km) 0.7 0.5
3 Nox mass emission (g/km) 0.5 0.5
4 Fuel consumption (km/1) 55 62
5 Max power (Ps) 11.7 12.5
10

It can be concluded from the above test values that there is a significant reduction in CO emissions from 1 g/km to 0.6 g/km and HC emissions from 0.7 g/km to 0.5 g/km. There is significant increase in fuel efficiency from 55 km/litre to 62 km/litre. The advantages mentioned above are obtained along with an improvement in peak power of the engine.
As can be seen from the figures, when the engine runs, the oil carried by the timing chain (3) when splashed, falls on the outer periphery of the sleeve (23) and leads its way back to the crankcase without being exposed to outside and causing leakage.
Usage of this sleeve (23) enables the use of a conventional "endless" type timing chain without any difficulty. The inner diameter of the sleeve (23) is so chosen that the spark plug can be removed without a spark plug spanner without any difficulty. This type of design is very critical since the same available in said engines is limited unlike in bigger engines.
11

The description and the figures provided in this patent application, indicate the location of spark plugs diametrically opposite to each other. However, depending upon the design requirements, it may be necessary to change the locations at predetermined angular positions.
It will be appreciated that the invented engine with improved combustion characteristics for efficient air fuel mixture burning as described and illustrated in the drawing that it would be possible to modify and/or alter the various features thereof by person skilled in the art without deviating from the scope of the invention. The applicant intends to include those modifications and variations within the scope and the ambit of this invention.
12

WE CLAIM;
1. An improved Internal Combustion Engine working on four stroke principle, having two valves per cylinder, for efficient burning of lean air fuel mixture used in engines wherein the diameter of cylinder bore ranges between 45 mm and 70 mm characterized in that said Internal Combustion Engine comprises a pair of spark plugs, namely a first spark plug (21) and a second spark plug (22), a cylinder head (25), a sleeve (23), a pair of sealing means (24, 24a), fixing means (26) and a sleeve cap (27); said first and second spark plugs (21 and 22) being fitted to said cylinder head (25) and capable of igniting air fuel mixture at predetermined instant; said second spark plug (22) being housed within said sleeve (23) located within timing chain cavity; said sleeve (23) being detachably push fitted to said cylinder head (25) and held in position by said fixing means (26), said sealing means (24, 24a) being adapted between said cylinder head (25) and the outer periphery of said sleeve (23) and said sleeve cap (27) being fitted on said cylinder head (25).
2. An improved Internal Combustion Engine as claimed in Claim 1 wherein the said pair of spark plugs (21 and 22) are fitted subsequently diametrically opposite to each other.
13

3. An improved Internal Combustion Engine as claimed in Claims 1 and 2 wherein said fixing means (26) is a circlip or a screw.
4. An improved Internal Combustion Engine as claimed in Claims 1 and 2 wherein said pair of sealing means (24 and 24a) is an O ring or an oil seal.
5. An improved Internal Combustion Engine as claimed in any of the preceding claims wherein the sleeve cap (27) is made of resilient material, such as Nylon, PVC, rubber.
6. An improved Internal Combustion Engine working on four stroke principle, having two valves per cylinder, for efficient burning of lean air fuel mixture used in engines wherein the diameter of cylinder bore ranges between 45 mm and 70 mm characterized in that said Internal Combustion Engine comprises a spark plug (22), a cylinder head (25), a sleeve (23), a pair of sealing means (24, 24a), fixing means (26) and a sleeve cap (27); said spark plug (22) being fitted to said cylinder head (25) and capable of igniting air fuel mixture at predetermined instant; said spark plug (22) being housed within said sleeve (23) located within timing chain cavity; said sleeve (23) being detachably push fitted to said
14

cylinder head (25) and held in position by said fixing means (26), said sealing means (24, 24a) being adapted between said cylinder head (25) and the outer periphery of said sleeve (23), and said sleeve cap (27) being fitted on said cylinder head (25).
7. An improved single cylinder Internal Combustion Engine working on four stroke principle having two valves for efficient burning of lean air fuel mixture used in engines wherein the diameter of said cylinder bore ranges between 45 mm and 75 mm substantially as herein described and as illustrated in the drawings accompanying the Specification.
Dated this 5th day of November 2004.
M K CHAKRABARTI OF L S DAVAR & CO
Agent for the applicant
15

Documents:

649-MUM-2002-CANCELLED PAGES(8-11-2004).pdf

649-MUM-2002-CLAIMS(GRANTED)-(7-7-2005).pdf

649-mum-2002-claims.doc

649-mum-2002-claims.pdf

649-MUM-2002-CORRESPONDENCE 1(10-3-2010).pdf

649-MUM-2002-CORRESPONDENCE(26-10-2010).pdf

649-MUM-2002-CORRESPONDENCE(8-12-2004).pdf

649-MUM-2002-CORRESPONDENCE(IPO)-(3-12-2010).pdf

649-mum-2002-correspondence-others.pdf

649-mum-2002-correspondence-received-030304.pdf

649-mum-2002-correspondence-received-040703.pdf

649-mum-2002-correspondence-received-051104.pdf

649-mum-2002-correspondence-received-090802.pdf

649-mum-2002-correspondence-received-140504.pdf

649-mum-2002-correspondence-received.pdf

649-mum-2002-correspondnece(17-11-2004).pdf

649-mum-2002-correspondnece(ipo)-(11-11-2004).pdf

649-mum-2002-descripiton (complete).pdf

649-MUM-2002-DESCRIPTION(COMPLETE)-(7-7-2003).pdf

649-MUM-2002-DESCRIPTION(GRANTED)-(7-7-2005).pdf

649-MUM-2002-DESCRIPTION(PROVISIONAL)-(16-7-2002).pdf

649-MUM-2002-DRAWING(16-7-2002).pdf

649-MUM-2002-DRAWING(7-7-2003).pdf

649-MUM-2002-DRAWING(GRANTED)-(7-7-2005).pdf

649-mum-2002-drawings.pdf

649-MUM-2002-FORM 1(12-8-2002).pdf

649-MUM-2002-FORM 1(16-7-2002).pdf

649-MUM-2002-FORM 13(27-4-2010).pdf

649-MUM-2002-FORM 2(COMPLETE)-(7-7-2003).pdf

649-MUM-2002-FORM 2(GRANTED)-(7-7-2005).pdf

649-MUM-2002-FORM 2(PROVISIONAL)-(16-7-2002).pdf

649-MUM-2002-FORM 2(TITLE PAGE)-(COMPLETE)-(7-7-2003).pdf

649-MUM-2002-FORM 2(TITLE PAGE)-(GRANTED)-(7-7-2005).pdf

649-MUM-2002-FORM 2(TITLE PAGE)-(PROVISIONAL)-(16-7-2002).pdf

649-MUM-2002-FORM 26(26-10-2010).pdf

649-MUM-2002-FORM 3(16-7-2002).pdf

649-mum-2002-form-1.pdf

649-mum-2002-form-13.pdf

649-mum-2002-form-19.pdf

649-mum-2002-form-2.doc

649-mum-2002-form-2.pdf

649-mum-2002-form-26.pdf

649-mum-2002-form-3.pdf

649-mum-2002-form-5.pdf

649-MUM-2002-PETITION UNDER RULE 137(8-11-2004).pdf

649-MUM-2002-SCHEDULE TO FORM 3(8-11-2004).pdf

649-MUM-2002-SPECIFICATION(AMENDED)-(8-11-2004).pdf

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Patent Number

195904

Indian Patent Application Number

649/MUM/2002

PG Journal Number

01/2010

Publication Date

01-Jan-2010

Grant Date

Date of Filing

16-Jul-2002

Name of Patentee

BAJAJ AUTO LTD

Applicant Address

Indian Limited Company Akurdi, Pune 411 035

Inventors:

#	Inventor's Name	Inventor's Address
1	JOSEPH A	Indian Limited Company Akurdi Pune 411 035

PCT International Classification Number

F02P15/02

PCT International Application Number

N/A

PCT International Filing date

PCT Conventions:

#	PCT Application Number	Date of Convention	Priority Country
1			NA