Description:FIELD OF THE INVENTION
[001] The present invention generally relates to an internal combustion engine. More particularly, the present invention relates to a variable valvetrain system for an internal combustion engine.

BACKGROUND OF THE INVENTION
[002] Generally, in conventional motor vehicles, a valvetrain assembly is present in the cylinder head for ensuring that the valves in the cylinders are opened and closed for inlet and outlet of the fuel and air, in synchronization with the movement of the piston. The opening and closing of the valves depend on the configuration of the cam-lobe provided for that specific valve. Generally, the timing of opening and closing of the valve is static and this static timing has an impact on the fuel consumption and generated power.
[003] Conventionally, a cylinder head assembly consists of valvetrain parts which includes a camshaft, a rocker arm, and a timing chain which are all moving parts that are in contact. The multitude of moving parts contributes to the losses in terms of friction due to moving parts, heat generation, wear & tear, vibrations due to unbalanced rocking and unbalanced rotational masses. The high number of parts also makes the cylinder head heavier and bulkier.
[004] Specifically, when a variable valvetrain system is provided such that the timing of the opening and closing of the valves can be varied or adjusted, the number of parts are further increased, which further increases the frictional losses, wear and tear, heat generation and excessive vibrations due to unbalanced rocking and rotational masses.
[005] Thus, there is a need in the art for a variable valvetrain system for an internal combustion engine which addresses at least the aforementioned problems.

SUMMARY OF THE INVENTION
[006] In one aspect, the present invention is directed towards a variable valvetrain system for an internal combustion engine. The variable valvetrain system has a driving mechanism. The system further has a cam-disc, wherein the cam-disc is rotatably driven by the driving mechanism. The cam-disc has a top surface and a bottom surface. The top surface of the cam-disc is configured to be in contact with the driving mechanism, and the bottom surface has a protrusion. The system further has a valve. The valve is in contact with the bottom surface of the cam-disc, wherein on rotation of the cam-disc by the driving mechanism, the protrusion pushes the valve thereby converting the rotational motion of the cam-disc to translational motion of the valve for operating the valve.
[007] In a further embodiment of the invention, the protrusion is provided on an outer periphery of the bottom surface of the cam-disc.
[008] In a further embodiment of the invention, the driving mechanism has at least one of an electric drive means or a mechanical drive means or an electro- mechanical drive means.
[009] In a further embodiment of the invention, the bottom surface of the cam-disc has an endless groove provided on the bottom surface of the cam-disc.
[010] In a further embodiment of the invention, the valve has a valve stem and a valve seat, wherein a top end of the valve stem is configured to be received in the endless groove on the bottom surface of the cam-disc.
[011] In a further embodiment of the invention, the top end of the valve stem has a round profile thus allowing the top end of the valve stem to be received in the endless groove.
[012] In a further embodiment of the invention, the system has a return spring is connected to the valve and the return spring is configured to keep the valve abutted against the bottom surface of the cam-disc.
[013] In a further embodiment of the invention, the driving mechanism has a drive gear. Further, the driving mechanism has a cam-disc having a driven gear provided on the top surface of the cam-disc. Furthermore, the driven gear is configured to mesh with the drive gear for driving the cam-disc.

BRIEF DESCRIPTION OF THE DRAWINGS
[014] Reference will be made to embodiments of the invention, examples of which may be illustrated in accompanying figures. These figures are intended to be illustrative, not limiting. Although the invention is generally described in context of these embodiments, it should be understood that it is not intended to limit the scope of the invention to these particular embodiments.
Figure 1 illustrates a perspective exploded view of an internal combustion engine, in accordance with an embodiment of the present invention.
Figure 2 illustrates a perspective exploded view of a variable valvetrain system for the internal combustion engine, in accordance with an embodiment of the present invention.
Figure 3 illustrates a bottom perspective view of a cam-disc of the variable valvetrain system, in accordance with an embodiment of the present invention.
Figure 4 illustrates a perspective view of the variable valvetrain system, in accordance with an embodiment of the present invention.

DETAILED DESCRIPTION OF THE INVENTION
[015] The present invention relates to an internal combustion engine. More particularly, the present invention relates to a variable valvetrain system for an internal combustion engine. The internal combustion engine of the present invention is typically used in a vehicle such as a two wheeled vehicle, or a three wheeled vehicle, or a four wheeled vehicle, or other multi-wheeled vehicles as required. However, it should be understood that the internal combustion engine as illustrated may find its application in any non-automotive application using an internal combustion engine.
[016] Figure 1 and Figure 2 illustrates a perspective exploded view of a variable valvetrain system 100 for an internal combustion engine 10. As illustrated, the variable valvetrain system 100 comprises a driving mechanism 110. the driving mechanism 110 comprises at least one of an electric drive means or a mechanical drive means or an electro-mechanical drive means.
[017] As illustrated further, the variable valvetrain system 100 comprises a cam-disc 120. As illustrated, the cam-disc 120 is operably connected to the driving mechanism 110 and the cam-disc 120 is rotatably driven by the driving mechanism 110. As further illustrated, the cam-disc 120 has a top surface 122 and a bottom surface 124, wherein the top surface 122 of the cam-disc 120 is configured to be in contact with the driving mechanism 110. Further, the bottom surface 124 comprises a protrusion 126.
[018] As specifically referred in Figure 2, the variable valvetrain system 100 further has a valve 130. The valve 130 is configured to be in contact with the bottom surface 124 of the cam-disc 120. Herein, on rotation of the cam-disc 120 by the driving mechanism 110, the protrusion 126 pushes the valve 130 thereby converting the rotational motion of the cam-disc 120 to translational motion of the valve 130 for operating the valve 130. In an embodiment, as illustrated in Figure 2, the protrusion 126 is provided on an outer periphery of the bottom surface 124 of the cam-disc 120. Thus, in operation, during rotation of the cam-disc 120, whenever the protrusion 126 passes over the valve 130, by virtue of the profile of the protrusion 126, the protrusion 126 pushed down the valve 130, thus opening the valve 130. Further, after the protrusion 126 has passed over the valve 130, the valve 130 is pushed back up again, thus closing the valve 130. In an embodiment, the valve 130 is an intake valve wherein opening of the valve 130 allows the air fuel mixture to enter a cylinder of the internal combustion engine 10. In another embodiment, the valve 130 is an exhaust valve wherein opening of the valve 130 allows the exhaust gases to exit the cylinder of the internal combustion engine 10.
[019] Further, as mentioned hereinbefore, in an embodiment, the driving mechanism 110 comprises at least one of an electric drive means or a mechanical drive means or an electro-mechanical drive means. Thus, the movement of the driving mechanism 110 can be controlled as per requirement, wherein varying the speed of the movement of the driving mechanism 110 results in varying of the timing of the opening and closing of the valve 130, thus achieving a variable valvetrain system 100. In an embodiment, the driving mechanism 110 comprises an electric drive means and movement of the driving mechanism 110 is controlled by means of a control unit.
[020] Reference is made to Figure 3, which illustrates a bottom perspective view of the cam-disc 120. As illustrated in Figure 3, to allow for the valve 130 to remain in contact with the cam-disc 120 and to allow rotational movement of the cam-disc 120, the bottom surface 124 of the cam-disc 120 comprises an endless groove 128 provided on the bottom surface 124 of the cam-disc 120. Further, as referenced in Figure 2, the valve 130 comprises a valve stem 132 and a valve seat 134, wherein the valve seat 134 is configured to open or close the opening in the cylinder of the internal combustion engine 10. Herein, a top end 132A of the valve stem 132 is configured to be received in the endless groove 128 on the bottom surface 124 of the cam-disc 120. Further, to facilitate the communication of the top end 132A of the valve stem 132 with the endless groove 128 on the bottom surface 124 of the cam-disc 120, the top end 132A of the valve stem 132 has a round profile thus allowing the top end 132A of the valve stem 132 to be received in the endless groove 128. The round profile of the top end 132A of the valve stem 132 allows the top end 132A to be received in the endless groove 128 and allows seamless and smooth relative motion between the top end 132 and the endless groove 128.
[021] Reference is made to Figure 1, wherein in an embodiment, the variable valvetrain system 100 comprises a return spring 140 connected to the valve 130. The return spring 140 is configured to keep the valve 130 abutted or pushed against the bottom surface 124 of the cam-disc 120. The provision of the return spring 140 allows the valve 130 to remain in place. Further, specifically after the protrusion 126 has passed over the valve 130, the provision of the return spring 140 results in the valve 130 being pushed back up again, thus closing the valve 130.
[022] In the embodiment depicted in Figure 4, to transmit the motion of the driving mechanism 110 to the cam-disc 120, the driving mechanism 110 comprises a drive gear 112, and cam-disc 120 comprises a driven gear 150. The driven gear 150 is provided at the top surface 122 of the cam-disc 120. Herein, the driven gear 150 configured to mesh with the drive gear 112, and thus movement of the driving mechanism 110 is transmitted to the driven gear 150 for driving the cam-disc 120.
[023] Advantageously, the present invention provides a variable valvetrain system wherein a variable valve timing is achieved by means of a driving mechanism and the cam-disc. Further, the provision of the cam-disc for the variable valvetrain and the valve stem being received in the groove of the cam-disc allows for reduction of frictional losses, heat generation and wear and tear. This also results in an increase in the durability of the variable valvetrain system.
[024] Further, since the variable valvetrain system of the present invention achieves variable valvetrain timing using a compact system, the noise, vibration and harshness (NVH) levels of the internal combustion engine are substantially reduced. Further, the variable valvetrain system being compact also results in reduction in size and weight of the internal combustion engine.
[025] Overall, provision of a variable valvetrain system in which timing of the opening and closing of the valves can be controlled as per requirement results in improved performance of the internal combustion engine, better fuel economy and better pickup and power delivery by the internal combustion engine.
[026] While the present invention has been described with respect to certain embodiments, it will be apparent to those skilled in the art that various changes and modification may be made without departing from the scope of the invention as defined in the following claims.

List of Reference Numerals
10: Vehicle
100: A variable valvetrain system
110: Driving mechanism
112: Drive gear
120: Cam- disc
122: Top surface of the cam-disc
124: Bottom surface of the cam-disc
126: Protrusion
128: Endless Groove
130: Valve
132: Valve stem
132A: Top end of the valve stem
134: Valve seat
140: Return spring
150: Driven gear , Claims:WE CLAIM:
1. A variable valvetrain system (100) for an internal combustion engine (10), the variable valvetrain system (100) comprising:
a driving mechanism (110);
a cam-disc (120), the cam-disc (120) being rotatably driven by the driving mechanism (110), the cam-disc (120) comprising a top surface (122) and a bottom surface (124), the top surface (122) of the cam-disc (120) being configured to be in contact with the driving mechanism (110), and the bottom surface (124) comprising a protrusion (126); and
a valve (130), the valve (130) configured to be in contact with the bottom surface (124) of the cam-disc (120), wherein on rotation of the cam-disc (120) by the driving mechanism (110), the protrusion (126) pushes the valve (130) thereby converting the rotational motion of the cam-disc (120) to translational motion of the valve (130) for operating the valve (130).

2. The variable valvetrain system (100) as claimed in claim 1, wherein the protrusion (126) is provided on an outer periphery of the bottom surface (124) of the cam-disc (120).

3. The variable valvetrain system (100) as claimed in claim 1, wherein the driving mechanism (110) comprises at least one of an electric drive means or a mechanical drive means or an electro-mechanical drive means.

4. The variable valvetrain system (100) as claimed in claim 1, wherein the bottom surface (124) of the cam-disc (120) comprises an endless groove (128) provided on the bottom surface (124) of the cam-disc (120).

5. The variable valvetrain system (100) as claimed in claim 4, wherein the valve (130) comprises a valve stem (132) and a valve seat (134), wherein a top end (132A) of the valve stem (132) is configured to be received in the endless groove (128) on the bottom surface (124) of the cam-disc (120).

6. The variable valvetrain system (100) as claimed in claim 5, wherein the top end (132A) of the valve stem (132) has a round profile thus allowing the top end (132A) of the valve stem (132) to be received in the endless groove (128).

7. The variable valvetrain system (100) as claimed in claim 1, comprising a return spring (140) connected to the valve (130), the return spring (140) being configured to keep the valve (130) abutted against the bottom surface (124) of the cam-disc (120).

8. The variable valvetrain system (100) as claimed in claim 1, wherein the driving mechanism (110) comprises a drive gear (112), and cam-disc (120) comprises a driven gear (150) provided at the top surface (122) of the cam-disc (120), the driven gear (150) configured to mesh with the drive gear (112) for driving the cam-disc (120).

Dated this 03rd day of March 2023
TVS MOTOR COMPANY LIMITED
By their Agent & Attorney

(Nikhil Ranjan)
of Khaitan & Co
Reg No IN/PA-1471