FIELD OF INVENTION

The present invention relates to a variable valve timing mechanism and more specifically to the variable valve timing mechanism used in an internal combustion engine of a motorized vehicle.

BACKGROUND OF THE INVENTION

Generally, in two wheeled vehicles valve timing for intake and exhaust valve timing is fixed and cannot change with the speed of the engine. In some high power two wheelers hydraulic mechanism is present for variable valve timing but that cannot not be installed in low cost and low power two wheelers due to design and cost constraints. Thus there is a need of a mechanism which can facilitate variable valve timing.

SUMMARY OF THE INVENTION

The present invention related to a variable valve timing mechanism for an internal combustion engine. The variable valve timing mechanism is having a cam shaft assembly, a timing flange and a cam sprocket. Said Cam shaft assembly comprises a camshaft, multiple camshaft bearing, an intake cam lobe and an exhaust cam lobe. The intake cam lobe and the exhaust cam lobe are secured over the cam shaft and the cam shaft bearings are fixed on front and rear ends of the cam shaft. Said timing flange is having multiple timing pins and is secured on front end of the cam shaft. The cam sprocket is having multiple numbers of pin slots, pivot pins, fly weights with multiple pivot pin slots and timing adjustment slots and a spring unit connected to each other. Said cam sprocket is secured over the timing flange through timing pins. The timing pin is fixed timing pin slot and the pivot pin is secured inside the pivot pin slot. The spring unit, mentioned above, is joining the fly weights to each other.

BRIEF DESCRIPTION OF THE ACCOMPANYING DRAWING

The present invention will become more fully understood from the detailed description given herein below and the accompanying drawing which is incorporated in and constitute embodiments of the invention, illustrate several aspects of the invention and together with a description of the embodiments serve to explain the principles of the invention and thus, are not limited of the present invention and a brief description of the drawing is as follows:

Figure 1 is the exploded view of the claimed invention depicting the main embodiments.

Figure 2 is depicting the essential embodiment of the invention in an exemplary enabling condition.

Figure 3 is showing an exemplary representation of the essential embodiment of the invention.

Figure 4 is explaining the enabling mechanism of the claimed invention.

Figure 5 is showing an exemplary arrangement of an embodiment of the claimed invention.

Figure 6 is depicting an exemplary arrangement of another embodiment of the claimed invention.

DETAILED DESCRIPTION OF THE INVENTION

The embodiments disclosed below are not intended to be exhaustive or to limit the invention to the precise forms disclosed in the following detailed description. Rather, the embodiments are chosen and described so that others skilled in the art may utilize their teachings. The invention may have application to all types of two wheeled vehicles.

Figure 1 is an exemplary representation of the embodiments of the claimed valve timing mechanism (114) (hereinafter mechanism). Said mechanism (114) comprises a cam shaft assembly (113) is made up of a cam shaft (102) attached with two cam shaft bearings (101,105) attached on the front (105) and rear (101) end of the cam shaft (102) and an intake cam lobe (103) and an exhaust cam lobe (104) secured over the cam shaft (102).

The mechanism (114) further comprises a timing flange (106) with multiple timing pins (107) and these timing pins (107) are fixed inside the slot (110) provided over the cam sprocket (100). The cam sprocket (100) also comprises of multiple pivot pins (109) provided on the fly weight (111) which are connecting the cam sprocket (100) with the fly weights (111).

In the exemplary figure 1 provided, two flyweights (111) are shown, which provides the best enablement configuration for the mechanism (114). The fly weights (111) are connected through the tension spring unit (108), which is flexible and changes is length are required as per the speed and hence the valve timing got changed.

Further, figure 2 is showing the slow speed mode for the essential embodiments of the invention. As shown in figure 1, cam sprocket (100) is fixed on the front part of the mechanism (114). During slow speed of the engine the tension spring (102) remains at the predefined length and keep flyweights (111) at a specific predefined location, due to timing pin (107) location into the timing adjustment mechanism (slot) (115), which results in the control of the valve timing for intake and exhaust.

Further, as the speed increases, as shown in figure 3, the fly weights (111) spreads apart due to centrifugal force resulting which the tension spring (111) spreads. The fly weights are pivotally attached to the timing adjustment slots (115) through the timing pins (107) and due the change in position of the fly weights (111) positioning of the timing pin (107) changes, resulting which the intake and exhaust angle A changes causes more efficiency in case of the higher speed of vehicle.

Further, reference is made to figure 4 in order to explain the enablement of the claimed mechanism. As shown in stage 4a timing pins 107 are positioned in the lower timing adjustment slot 115 and as the speed increases, fly wheels 111 starts falling apart and the timing pin 115 moves to another slot 115 and hence the intake and exhaust angle changes by A which results into more efficient engine output at higher speed and at a predefined stage the reinforcement unit 108 (tension spring) pulls fly wheels 111 at previous position.

Figure 5 and figure 6 are providing other exemplary embodiments for the reinforcement unit 108 and the timing adjustment mechanism 115. As shown in figure external force for the reinforcement unit 108 can be used for reinforcement of the fly wheels 111 in position and the timing adjustment unit 115 can also be a smooth curved path for the timing pin 107.

WHAT IS CLAIMED IS

1) A Variable valve timing mechanism for an internal combustion engine, comprising a cam shaft assembly defining a camshaft fixed with a plurality of bearings, an intake cam lobe and an exhaust cam lobe secured over the camshaft, a timing flange secured on front end of the cam shaft and comprises atleast one timing pin element, and a cam sprocket secured over the timing flange through said timing pin element and said cam sprocket comprises at least one timing pin slot, at least one pivot pin, a plurality of fly weight with atleast one pivot pin slot and at least one timing adjustment mechanism and atleast one reinforcement unit configured to reinforce position of said plurality of fly weights.

2) The variable valve timing mechanism, as claimed in claim 1, wherein the plurality of timing pin is secured in the timing adjustment mechanism.

3) The variable valve timing mechanism, as claimed in claim 2, wherein, the timing adjustment mechanism is defining a mechanism with a plurality of timing adjustment slots.

4) The variable valve timing mechanism, as claimed in claim 2, wherein, the timing adjustment mechanism is defining a mechanism with a smooth curved path.

5) The variable valve timing mechanism, as claimed in claim 1, wherein, the plurality of pivot pin is secured inside the plurality of pivot pin slot.

6) The variable valve timing mechanism, as claimed in claim 1, wherein, said reinforcement unit is a coiled structure.