Air cooling structure for scooter type motorcycle

Field of the invention

The present invention relates generally to a cooling mechanism for a scooter type motorcycle and more particularly pertains to an air cooling structure for a scooter type motorcycle.

Background of the invention

Typically in a scooter type motor cycle, the portion below the seat is covered with a body cover (also called as side panel) present on either side of the vehicle and connected to a body frame. The two body covers coupled with an underseat cover form an enclosed space (or cabin) below the seat to make the motorcycle visually more attractive as the detailed interiors are not visible to an onlooker. A swinging power unit is located below the seat at a lower rear portion of the motorcycle spanning from the underseat cover to the rear wheel hub. In particular, the anterior portion of the power unit comprising a cylinder head is substantially enclosed in the enclosed space.

The partially enclosed power unit is generally cooled by forced cooling through a fan mounted on the right side of the crankcase and forcing the air inside a cooling cowl which further directs this air towards the cylinder head. Additional cooling is obtained by natural air flowing from the motorcycle front into the scooter type motorcycle from underneath the floorboard when the vehicle is in motion or in idle state. This air enters the enclosed space between the body covers.

The construction of body frame of the scooter type motorcycle, however, poses problems for the incoming air. The body frame comprises two side tubes held together by a cross member at a lower portion of the motorcycle. The air travelling underneath the floorboard is obstructed by the cross member of the body frame. The incoming air strikes the cross member and is scattered due to which the cooling effect of the incoming air is reduced considerably. As a result, the power unit inner to the body cover is not optimally cooled. The effect is more profound on the cylinder head as it is substantially enclosed within the respective body covers and the underseat cover and hence requires more cooling. Overall under the present construction, the incoming air does not efficiently cool the cylinder head and hence the air temperature in the enclosed space remains high.

Furthermore the storage component located typically below the seat also becomes heated at its bottom due to increase in temperature of the enclosed power unit when at work. The high temperature may be detrimental to the articles stored in the storage compartment.

A need therefore exists to provide an improved and efficient cooling mechanism for cooling the swinging power unit in a scooter type motorcycle without being deflected by the constituents of the body frame so that the incoming air does not scatter much and is utilized optimally in cooling the power unit. The present invention is directed to overcoming one or more problems as set forth above.

Summary of the invention

It is an object of the present invention to disclose a cooling system comprising an air cooling structure that aims for providing guidance to the incoming air to reduce the resistance caused by body frame constituents thereby increasing the air flow rate into the enclosed space and facilitating efficient cooling of the power unit, particularly cylinder head, enclosed within the body cover of a scooter type motorcycle.

The present invention, in accordance with one embodiment thereof, discloses an air cooling structure for a scooter type motorcycle connected to a bottom cover present underneath a floorboard and is carved out of the bottom cover and extending from an air entry point under the floorboard up to a cross member of a body frame of the scooter type motorcycle. The air cooling structure is angularly disposed with respect to the longitudinal axis of the scooter type motorcycle in such a way that it prevents the incoming air from flowing into the cross member of the body frame so that the incoming air is directed towards the power unit disposed below the seat of the motorcycle.

Another objective of the present invention is to provide an efficient cooling channel for a scooter type motorcycle that increases the cooling efficiency of the natural incoming air thereby reducing the temperature of the power unit as well as the storage compartment and increase the shelf life of various articles placed therein.

Yet another object of the present invention is to decreases the oil consumption owing to reduced oil temperature inside the power unit due to the proposed air cooling structure.

Another object of the present invention is to propose a cooling system for reducing the temperature of the enclosed space below the seat where the power unit is located when the power unit is not in idle condition.

The foregoing objectives and summary provide only a brief introduction to the present invention. To fully appreciate these and other objects of the present invention as well as the invention itself, all of which will become apparent to those skilled in the art, the ensuing detailed description of the invention and the claims should be read in conjunction with the accompanying drawings. However, it should be understood that the detailed description and specific examples, while indicating preferred embodiments of the invention, are given by way of illustration only, since various changes and modifications within the spirit and scope of the invention will become apparent those skilled in the art from this detailed description.

Brief description of the drawings

Figure 1 shows a schematic view of a typical two wheeled scooter type motorcycle.

Figure 2 is an exploded view of an embodiment of a cooling system comprising an air cooling structure according to the present invention.

Figure 3 shows a top view of the air cooling structure according to the present invention.

Figure 4 shows the perspective view of the top surface of the air cooling structure.

Figure 5 shows rear view of the air cooling structure.

Figure 6 depicts top view of a second embodiment of the air cooling structure according to the present invention.

Figure 7 illustrates front view of the second embodiment of the air cooling structure.

Figure 8 is a table showing the enclosed space air temperature with and without the cooling system.

Figure 9 illustrates the temperature at the bottom of storage compartment of the said motorcycle with and without the cooling system.

Detailed description of the invention

In the ensuing exemplary embodiments, the vehicle is a two wheeled scooter type motorcycle with a swinging power unit. However it is contemplated that the disclosure in the present invention may be applied to any like vehicle without defeating the spirit of the invention.

Further "front" and "rear", and "left" and "right" referred to in the ensuing description for the illustrated embodiment refer to front and rear, and left and right directions as seen in a state of being seated on a seat of the scooter type motorcycle and looking forward. Furthermore, a longitudinal axis refers to a front to rear axis relative to the scooter type motorcycle, while a lateral axis refers generally to a side to side, or left to right axis relative to the scooter type motorcycle.

The present invention is now described briefly in connection with the rendered drawings. It should be noted that like elements are denoted by the same reference numerals throughout the description. The detailed explanation of the constitution of parts other than the invention which constitutes an essential part has been omitted at opportune places.

Figure 1 illustrates the side view of a concerned scooter type motorcycle with a swinging power unit. Typically such a vehicle includes a body frame assembly made up of several tubes welded together which usually supports the body of the said vehicle. The vehicle has a steerable front wheel 110 and a driven rear wheel 111 driven by driving force generated by an engine 102.

The frame assembly 101 of the saddle ride type vehicle with the swinging power unit is an elongated structure, which typically extends from a forward end to a rearward end of the vehicle. It is generally convex in shape, as viewed from a side elevational view. The said frame assembly 101 includes a main frame and may also have a sub-frame. The sub-frame is attached to the main frame using appropriate joining mechanism. The frame assembly 101 includes a head tube (not shown) and a down tube that extends downward from head tube. Two side tubes 301 are provided in the frame assembly, one each on either side of the longitudinal axis of the scooter type motorcycle, which are connected by a cross member 302. The side tubes 301 and cross member 302 are not visible to an onlooker in a ready to ride scooter type motorcycle as shown in Figure 1. The frame assembly is covered by a plurality of vehicle body covers including a front panel 115, a leg shield 116, an under seat cover 117 and a side panel 112. For the purpose of illustration, only side panel 112 will henceforth be referred to as "body cover" in the ensuing description.

A handlebar assembly 105 and a seat assembly 106 are supported at opposing ends of the frame assembly and a generally open area is defined there between known as floorboard 107 which functions as a place where the front rider rests his feet. The seat for a driver and a pillion is placed forward to the fuel tank (not shown) and rearwardly of the floorboard 107. A bottom cover (not shown in Figure 1) is provided at the bottom of the floorboard.

A storage compartment for storing important articles is provided immediately below the seat 106. A fuel tank (not shown) that stores fuel that is supplied to the engine is disposed at the rear end of the vehicle above the rear wheel. It is present on the upper side of the power unit along with a fuel tank cap. A muffler is provided to the right side of the rear wheel, and connects to the power unit. A side stand provided in proximity of the power unit and fixed to the left side of the body frame supports the motorcycle such that the motorcycle inclines to the left side. A centre stand may also be provided.

A front fender 113 is located above the front wheel 110 to avoid the said motorcycle and its occupants from being splashed with mud. Likewise a rear fender 109 is placed between fuel tank and rear wheel 111, and to the outer side in the radial direction of rear wheel. Rear fender 109 inhibits rain water or the like from being thrown up by rear wheel 111.

Typically, front 103 and rear 114 suspension assemblies are operatively positioned between the front 110 and rear 111 wheels and the frame assembly. The front suspension assembly 103 commonly is a telescopic fork arrangement while the rear suspension assembly 114 is a hydraulic damped arrangement.

The body cover 112 is present on either side of the longitudinal axis of the scooter type motorcycle such that at least one body cover is present at the rear left side and one on the rear right side portion of the said motorcycle. Together both the body covers form an enclosed space below the seat assembly in close proximity with the underseat cover 117. This enclosed space is substantially surrounded on at least three sides.

In the said motorcycle, the rear suspension typically supports a power unit which is configured to drive the rear wheel 111 of the motorcycle. The power unit is structured such that an engine 102 and a swing case 108, which are well known for this form of scooter type motorcycle, are integrally constructed. The engine may be an internal combustion engine and the swing case is connected to a left side surface of a crankcase of the engine so as to extend forward.

The power unit is disposed on the vehicle frame below the seat 106 with one end of the swing case 108 attached to the rear wheel hub in such a way that the power unit is substantially angularly disposed to the ground. The other end of the power unit is mounted on the rear body frame. The engine 102 is arranged horizontally, that is, its crankshaft is placed at right angles to the longitudinal direction of the motorcycle body. An anterior portion of the power unit including a cylinder head (not shown) is partially enclosed by respective body covers 112 and underseat cover 117.

The said power unit is surrounded by a shroud (not shown) or a covering with a fan to enhance forced cooling of the power unit. This covering present over the power unit is known as cooling cowl and may be made of plastic resin or the likes.

The cooling system according to the present invention comprising an air cooling structure will now be explained in detail. The air cooling structure is referenced by the numeral 200. Figure 2 shows an exploded view of an embodiment of the bottom cover 206 along with air cooling structure 200
according to the present invention in the said scooter type motorcycle. In the figure, a front panel 115 is connected to the body frame and is mounted over it. The floorboard 107 is present behind the front panel 115 on the lower portion of the said motorcycle body. The bottom cover 206 is located underneath the floorboard 107. The construction is such that the body frame constituents of the scooter type motorcycle are sandwiched between the floorboard 107 and the bottom cover 206.

Figure 3 shows the air cooling structure 200 supported on the bottom cover 206. The bottom cover is mounted to the motorcycle body with the help of a plurality of mounting brackets 204. A side tube 301 is provided in the frame assembly on either side of the longitudinal axis of the scooter type motorcycle. The side tubes are connected by the cross member 302.

Figure 4 shows the perspective view of the top surface of the air cooling structure 200. The air cooling structure 200 is attached to the bottom cover 206 and is placed on the upper surface of the bottom cover 206 such that one end of the said structure, namely the bottom cover end 207, is in contact with the upper surface of the bottom cover 206 while the other end, namely the cross member end 203 is upwardly inclined and opens over the cross member 302 of the body frame. The two ends are at different elevations. Thus the air cooling structure 200 is approximately upwardly inclined along the longitudinal axis of the motorcycle.

An air entry point 202 is provided above the bottom cover end 207 of the air cooling structure 200 through which the natural incoming air can enter the construction. It is to be noted that generally the incoming air is cool and at atmospheric temperature. The air entry point 202 may be louvered so that it prevents the water and mud entry.

A space is provided in the air cooling structure 200 between the bottom cover end 207 and the cross member end 203 called as the air channel 201. The air channel 201 can be kept open or closed. In one embodiment of the present invention, the air channel 201 is rectangular in shape and kept open. In yet another embodiment of the present invention, the air channel 201 is kept closed and forms a conduit such that the incoming air after entering from the air entry point 202 flows through inside the said conduit.

There can be a plurality of aforementioned air cooling structures in a scooter type motorcycle. The referenced illustrations show two such air cooling structures, one each on either side of the central longitudinal axis of the scooter type motorcycle and spaced from each other. The space between the two air cooling structures is denoted by the numeral 205. The construction of both the air cooling structures is similar and they together form the said cooling system. The said air cooling structure can be an integrated module with the bottom cover or alternatively can be fitted in separately with the bottom cover.

The air cooling structure may be made of any material including sheet metal or plastic resin. According to one embodiment of the present invention, the air cooling structure is made of sheet metal with two aforementioned ends.

The enclosure of the anterior portion of the power unit by the body covers 112 and underseat cover 117 coupled with working of the power unit leads to temperature increase of the surrounding milieu. Forced cooling by the fan (not shown) through the cooling cowl leads to cooling of the power unit. However further decrease in air temperature of the enclosed space is desirable which is possible when the natural air is properly channelized into the enclosed space. Hence the air cooling structure 200 according to the present invention is structured in such a way that the incoming air is optimally utilised to reduce the air temperature of the enclosed space thereby increasing the cooling efficiency.

The working of the cooling system according to the present invention is now described. The cool incoming air enters at the air entry point 202, follows the path defined by the air cooling structure and strikes the approximately inclined air channel 201 causing the incoming air to flow upwards due to the construction of the air cooling structure. In the embodiment where the air channel 201 is made of sheet metal plate, the incoming air moves along the air channel 201 and does not strike the cross member 302 due to the elevated cross member end 203 of the air cooling structure. In another embodiment where the air channel 201 is made of plastic resin in the form of a conduit, the incoming air from the air entry point directly moves into and flows along the conduit. The conduit surface prevents the incoming air from scattering and focusses it to flow over the cross member 302 through the cross member end 203 of the air channel. In both the embodiments the angled entry of the incoming cool air bypasses the cross member 302 and the incoming air flows over the cross member without being scattered by the cross member thus reaching the enclosed space containing the anterior portion of the power unit, including the cylinder head. The incoming air due to its low temperature cools the power unit, including the cylinder head. The further decrease in temperature of the power unit in addition to forced cooling reduces the temperature of the already existing air in the enclosed space thereby increasing the cooling efficiency. The decrease in temperature also decreases engine oil consumption thereby decreasing the maintenance cost of the said motorcycle.

Furthermore, the temperature of the air in the enclosed space was measured both in presence and absence of air cooling structure as shown in the table of Figure 8. It was found that the presence of the air cooling structure reduces the enclosed space air temperature by about 20%. On the other hand, the temperature of bottom surface of the storage compartment is reduced by about 10% as illustrated in Figure 9. The reduction in the temperature of the storage compartment bottom surface increases the shelf life of any vegetable or articles placed in it.

Another embodiment of the cooling system according to the present invention is depicted in Figure 6 and Figure 7. The natural incoming air directly strikes the air cooling structure without any louvered air entry point from beneath the floorboard and is angularly drifted over the cross member 302. The air cooling structure guides the flow of air over the power unit.

The cooling system can be further enhanced by providing holes or openings at a lower curved portion of the front panel 115 present in proximity with the rear portion of the front fender 113 and invisible to an onlooker. The holes may be provided on either side of vertical axis of the motorcycle along with the air cooling structure provided at aforementioned places. The presence of these openings will further increase the air mass entering the aforementioned enclosed space thereby further reducing the air temperatures in the enclosed space.

From the forgoing description, it will be appreciated that the present invention offers many advantages. The air cooling structure according to the present invention coupled with forced air cooling provides efficient and better cooling to the cylinder head of the power unit. The angled entry of the incoming air bypasses the cross member of the body frame of the scooter type motorcycle and it reduces the air temperature of the enclosed space containing the power unit. Furthermore the said mechanism is easy to manufacture and since less machining operations are required, the cost incurred is less. As the temperature is reduced in the said enclosed space due to the proposed cooling system herein, the temperature at the lower surface of the storage compartment reduces thereby increasing the shelf life of the articles placed therein.

Although the expression "scooter type motorcycle" is used in this specification it is to be construed as including any other type of motor vehicle as well, to which this invention is applicable. The "enclosed space" referred to in the specification does not refer to a completely covered space or area surrounded on all sides but refers to a partially surrounded space or area.

The terms and expressions in this specification are of description and not of limitation and do not exclude any equivalents of the features illustrated and described, but it is understood that various other embodiments are also possible without departing from the scope and ambit of this Invention which will become apparent to those skilled in the art from this detailed description. Accordingly, the description is to be understood as an exemplary embodiment and reading of the invention is not intended to be taken restrictively.

We claim:

1. A cooling system for a scooter type motor cycle, the said scooter type motorcycle comprising a body frame including a cross member, an air cooled swinging power unit, a body cover, an underseat cover, a floorboard, a bottom cover; the said body cover present on either side of a rear portion of the said motorcycle, the said body cover and the underseat cover forming an enclosed space below a seat and the anterior portion of the air cooled power unit partially enclosed in the said enclosed space; the said cooling system comprising:

an air cooling structure positioned in the bottom cover extending from an air entry point under the floorboard up to the cross member of the body frame of said scooter type motorcycle, the said air cooling structure angularly disposed with respect to the longitudinal axis of the said scooter type motorcycle facilitating angled entry of incoming air from the motorcycle front, the incoming air flowing above the said cross member of the body frame so that the incoming air is directed towards the power unit disposed below the seat.

2. A cooling system for a scooter type motor cycle as claimed in claim 1, wherein the said air cooling structure comprises at least two ends, a cross member end in contact with the cross member and a
bottom cover end in contact with the bottom cover, the area connecting the two ends forming an air channel for the incoming air and directing the incoming air to flow over the cross member towards the anterior portion of enclosed power unit.

3. A cooling system for a scooter type motor cycle as claimed in claim 1, wherein one end of the said air cooling structure is located at the same elevation as the air entry point.

4. A cooling system for a scooter type motor cycle as claimed in claim 1 wherein a plurality of openings are provided at a lower inwardly curved portion of a front panel of the said motorcycle, the lower inward curved portion being present rearwardly of the front wheel and proximate to rear portion of the front fender.

5. An air cooling structure for a scooter type motorcycle for reducing the air temperature of a space enclosed by a body cover present on either side of the longitudinal axis of the scooter type motorcycle and an underseat cover, a power unit including a cylinder head present in the said space, the said air cooling structure positioned in contact with a bottom cover underneath a floorboard and structured to facilitate incoming air entry over a cross member of a body frame of the said motorcycle towards the said space for cooling the said power unit.

6. An air cooling structure for a scooter type motorcycle as claimed in claim 5 wherein the said air cooling structure is approximately inclined at an angle to the longitudinal axis of the said motorcycle
such that the said angle ranges from ten to sixty degrees with respect to the longitudinal axis of the said motorcycle.

7. A cooling system comprising an air cooling structure substantially as claimed in any of the preceding claims and illustrated with reference to the accompanying drawings.