Cooling system for internal combustion engine

Field of the invention

The present invention relates to "Cooling system for internal combustion engine" and more particularly to an efficient air-cooling system for a two stroke motorcycle engine.

Background of the invention

Heat dissipation in air cooled engines are carried out by providing cooling fins so that the surface area is increased around the cylinder block and the cylinder head and heat is taken out by the surrounding air. Normally these cooling fins are made of thin plates in order to make the cooling structure light. However, there is non-uniformity in heat dissipation owing to non-uniformity of air distribution around the engine. As a result of this, the engine performance is affected as a result of the limited heat dissipation in existing designs. Therefore, a need arises to provide means for improving the heat dissipation of the engine with respect to the present engine cylinder head and cylinder block designs.

Hence the main objective of the present invention is to provide an internal combustion engine with an improved air cooling system that not only provides a higher level of heat dissipation but also uniform distribution of heat around the engine.

Brief description of the invention

The engine cylinder block includes an extended cylindrical portion defining a cylindrical wall at the top of the combustion chamber, the improvement comprising providing means for receiving and supporting the cylinder head therein. The cylinder block top inner surface defines a portion of the receiving and supporting means for receiving the engine cylinder head, and a corresponding planar outer surface defines cooling fins for cooling the internal combustion engine.

The extended cylinder portion forming a cylindrical wall at the top of the combustion chamber includes plurality fins in an extended manner, such that higher level of heat dissipation and uniform heat distribution can be made possible, and thereby accomplishing the efficient heat exchange, and hence increasing the engine performance by improving the engine cooling efficiency. A ring, giving it a unity of parts, joins the top surface of the extended fins which serves to avoid vibrations, if any, and gives rigidity.

Brief description of the drawings

Figure 1 illustrates a motorcycle having a two-stroke engine

Figure 2 illustrates the front view of the engine block for a two-stroke engine according to the prior art

Figure 3 illustrates the top view of the engine block showing the airflow path according to the prior art

Figure 4 illustrates the front view of the engine block and cylinder head according to the present invention

Figure 5 illustrates the top view of the engine block and cylinder head showing the air flow path according to the present invention

Detailed description of the invention

A selected illustrative embodiment of the present invention will be now described with respect to the accompanying figures.

Figure 1 illustrates a motorcycle having a two-stroke engine 101. The said motorcycle comprises of a frame 102, front fork 103 attached to a pivot tube 104 of the vehicle frame 102, a front wheel 105 attached to these front forks 103, a handle bar 106 connected to the front forks 103, a fuel tank 107, a seat 108 attached to the upper rear portion of the vehicle frame, an two stoke engine unit 101 attached to the lower front section of the vehicle frame 102 below a foot board 109, a swing arm attached to a lower rear section of the vehicle frame 102, suspended by a rear shock absorber 110 from the vehicle frame 102 and a rear wheel 111 attached to a rear end of swing arm. The intake system of the engine comprises of a carburettor, intake duct and an air cleaner. The exhaust system of the engine comprises an exhaust pipe 117. The motorcycle is also provided with a side cover 112 for covering a side section of the vehicle frame 102, a seat cover for covering a rear section of the vehicle frame 102 below the seat 108, a front fender 113 for covering an upper part of the front wheel 105, and a rear fender 114 for covering an upper part of the rear wheel 111. In the present configuration, the engine 101 is arranged horizontally where the cylinder head faces the incoming air and thus cooling of the engine is accomplished. The engine 101 has two parts namely cylinder block 115 and cylinder head 116 as observed from the side view in Figure 1.

Figure 2 illustrates the front view of the engine block 101 along with the cylinder block 115 and cylinder head 116 for a two-stroke engine 101 according to the prior art. Here the peripheral structure of the two-stroke engine has been shown. The cooling fins 201 are arranged on all the sides of the cylinder block 115 and cylinder head 116 of the engine 101. There are gaps 202 between the cooling fins that provide circulation path for the incoming air to take off the heat from the cylinder head 116 and cylinder block 115.

Figure 3 illustrates the top view of the engine block 101 showing the airflow path 301 according to the prior art. The air flowing from the front strike follow the path 301 formed on the cylinder head 116 and consequently tries to cover the cylinder block 115 and has a cooling effect on the total structure. However path 301 formed by the cooling air is not efficient enough to take out the total heat generated in the engine cylinder block 115 and as a result the engine efficiency is affected due to over heating.

Figure 4 illustrates the front view of the engine 101 according to the present invention. The cylinder block 115 includes an extended cylinder portion 401 defining a cylindrical wall at the top of the combustion chamber and provided means for receiving and supporting the cylinder head 116 therein. The cylinder block 115 top inner surface defines a portion of the receiving and supporting means for receiving the engine cylinder head 116, for cooling the internal combustion engine 101. These extended cooling fins 201 facilitate uniform heat dissipation from the engine 101 and thus leading to better cooling efficiency and engine performance.

Figure 5 illustrates the top view of the engine block 101 and cylinder head 116 showing the airflow path 301 according to the present invention. The cylinder head 116 is oriented when assembled to the cylinder block 115 such that the cylinder head 116 receiving wall and the top extended cylindrical wall of the cylinder block 115 defines a clearance space for perfect alignment of the cylinder head 116 onto the cylinder block 115 of the engine.

The cylinder head 116 further includes a curved top ring 402 and plurality of fins 201 at the outer periphery aligned with respect to the fins 201 provided in the cylinder block 115 for cooling the combustion chamber of the engine. The curved top ring 402 helps in maintaining structural integrity and prevention of vibrations. A conical-like protrusion is provided on the outer surface of wall of the cylinder head 116, such being located symmetrically of the point coincident with the respective cylinder axis.

The extended cylinder portion 401 forming a cylindrical wall at the top of the combustion chamber includes plurality fins 201 in an extended manner, such that a higher level of heat dissipation and uniform heat distribution is achieved.

Various modifications of the disclosed subject matter will become apparent to persons skilled in the art upon reference to the description of the subject matter. It is therefore contemplated that such modifications can be made without departing from the spirit or scope of the present subject matter as defined.

Part numbers associated with the description and drawings:
101. Two stroke engine
102. Frame
103. Front fork 113. Front fender
104. Pivot tube 114. Rear fender
105. Front wheel 115. Cylinder block
106. Handle bar 116. Cylinder head
107. Fuel tank 117. Exhaust pipe
108. Seat 201. Cooling fin
109. Foot board 202. Gaps between the cooling fins
110. Rear shock absorber 301. Path for airflow
111. Rear wheel 401. Extended cylindrical portion
112. Side cover

Claims:

We claim:

1. A cooling system for a two stroke internal combustion engine comprising:

a cylinder block having cooling fins on its outer surface; wherein the said cylinder block 115 includes an extended cylinder portion 401 forming cooling fins at the top of the combustion chamber includes plurality fins 201 in an extended manner.

2. A cooling system for a two-stroke internal combustion engine as claimed in Claim 1 wherein the extended cylinder portion 401 is aligned and joined by a ring 402 over its top surface.

3. A cooling system for a two-stroke internal combustion engine as claimed substantially as hereinbefore described with reference to and as illustrated in the accompanying drawings.