DESC:TECHNICAL FIELD
[001] The present subject matter relates to an internal combustion engine of a vehicle, more particularly, to a rocker shaft assembly for an internal combustion engine.
BACKGROUND
[002] Traditionally, internal combustion engines have been used for driving different kinds of automobiles. An internal combustion engine relies on burning fuel and produce power for driving a vehicle. In the recent past, there is a necessity to reduce fuel consumption and to provide higher power output without increasing number of parts. Hence, there is need to improve working of the internal combustion engine for improved fuel efficiency and reduced pollution.
BRIEF DESCRIPT ION OF THE DRAWINGS
[003] The present invention is described with reference to an embodiment of a two wheeled straddle type vehicle along with the accompanying figures. This invention is implementable in two-wheeled, three-wheeled vehicles and four wheeled vehicles. The same numbers are used throughout the drawings to reference like features and components. Further, the inventive features of the invention are outlined in the appended claims.
[004] Figure 1 illustrates a left side view of a vehicle, in accordance with an embodiment of the present subject matter.
[005] Figure 2 illustrates a front view of an internal combustion engine () of the vehicle, in accordance with an embodiment of the present subject matter.
[006] Figure 3 illustrates a sectional view of the cylinder block of the internal combustion engine , in accordance with an embodiment of the present subject matter.
[007] Figure 4 illustrates an exploded view of a valve lifting system for the internal combustion engine, in accordance with an embodiment of the present subject matter..
[008] Figure 5a illustrates a left side view of the valve lifting system in a disengaged position, in accordance with an embodiment of the present subject matter.
[009] Figure 5b illustrates a sectional view of the valve lifting system in the disengaged position, in accordance with an embodiment of the present subject matter.
[010] Figure 6a illustrates a left side view of the valve lifting system in an engaged position, in accordance with an embodiment of the present subject matter.
[011] Figure 6b illustrates a sectional view of the valve lifting system in the engaged position, in accordance with an embodiment of the present subject matter.
[012] Figure 7 illustrates a graphical plot of a high-lift condition and a low-lift condition of the valve lift vs. a crank angle as per the present invention.
DETAILED DESCRIPTION
[013] In order to improve fuel economy and performance of an internal combustion engine, manufacturers have attempted to improve valve timing. Valve timing is a precise timing of opening and closing of an intake and an exhaust valve. The intake valve allows air-fuel mixture to enter a combustion chamber and the exhaust valve controls exit of exhaust gases from the combustion chamber. Generally, the valve timing is controlled by a camshaft.
[014] Aligning to the desire of improving valve timing, manufacturers have introduced various types of valve timing mechanisms. Various valve timing mechanisms include a fixed valve timing and a variable valve timing mechanism. Under the fixed valve timing, the internal combustion engine needs a period of valve overlap at an end of an exhaust stroke when both the intake valve and the exhaust valve are open for achieving effective combustion process. The exhaust valve is closed just as fresh charge from the intake valve reaches a combustion chamber, to prevent loss of fresh charge or unscavenged exhaust gas. Generally, the fixed valve timing mechanism is used in low speed vehicles. In such vehicles, achieving high performance over a wide range of speeds is not possible.
[015] The variable valve timing mechanism is a technology where alteration is done in a timing of valve lifting. The internal combustion engine requires large amount of air during high operating or rotational speeds of the engine. If the intake valve is closed earlier, required quantity of air will not enter the combustion chamber within available time resulting in poor combustion process. On the contrary, if the intake valve is open for longer duration, the internal combustion engine will experience problems at lower speeds again leading to poor combustion process. Typically, the internal combustion engine of a straddle type vehicle may operate at more than several thousand revolutions per minute. Such vehicles are often restricted in freedom of layout space available to package vehicle aggregates and necessitate trade-off on plurality of vehicle and / or engine performance parameters. Therefore, achieving precise valve timing in a frugal way and within a compact layout of the straddle type two or three wheeled trike type vehicle is a major challenge.
[016] In a known valve timing mechanism, a valve control system is deployed wherein a poppet valve of the internal combustion engine is controlled through a rocker arm and a camshaft. The camshaft has a cam profile with a base circle portion and a lift portion. The rocker arm assembly has a profile with a valve pad in engagement with a stem portion of the poppet valve. The rocker arm includes a first cam follower adapted to be engaged by a lift portion of the cam profile as the camshaft rotates. The rocker arm includes a second cam follower which is disposed to be engaged by a lift portion of the cam profile. The engagement is at approximately the same time the lift portion of the cam profile moves out of engagement with the first cam follower. The second cam follower is movable relative to the rocker arm between an activated position in which engagement with the lift portion of the cam profile maintains the poppet valve in an open position, and a deactivated position in which engagement with the lift portion of the cam profile does not maintain the poppet valve in the open position. In such known art, a major drawback is that both the cam followers are actuated always during engagement.
[017] In another known art, a variable valve timing system is provided where the valve is operated selectively by either a first rocker arm or a second rocker arm which are supported for pivotal movement on the same rocker arm shaft. However, a major disadvantage of such selective variable valve timing system is that only one of the rocker arms operates the valve. Further, the lifting is changed selectively coupling the rocker arms for simultaneous operation and coupling between the rocker arms is achieved through an adjusting shim. Provision of adjusting shim even complicates the assembly of the valve timing system.
[018] In another known art, a main rocker arm is pivotally mounted on a rocker shaft and has a sub-rocker arm pivotally mounted thereon. The main rocker arm is arranged to open and close at least one poppet valve. A hydraulic lash adjuster is arranged at a free end of the main rocker arm to reduce valve clearance to zero. The sub-rocker arm is provided with a roller type cam follower which follows a low speed cam. The sub-rocker arm is provided with a follower which engages a high-speed cam and the main rocker arm is provided with a follower which engages a low speed cam. Provision of a sub-rocker arm makes valve timing a tedious process and may complicates the structure of the rocker shaft assembly. Additionally, such configuration ma increase the size of the cylinder head.
[019] In some conventional engines, multiple valves are used to cut off fuel supply at different valve timings during different speed requirement of the vehicle. However, use of multiple valves makes the engine bulky and increases the cost and weight of the vehicle.
[020] Furthermore, in conventional engines, there is a compromise between operation of the valve detection system either at high speed conditions or at low speed conditions. Thus, this makes the system partially workable or sub-optimal and does not satisfy all operating conditions of the vehicle.
[021] The conventionally known valve timing mechanism aims to achieve variable valve timing through several complex means. Such conventional valve timing mechanisms deploy of complex movement of cam follower. For example: provision of a second cam follower disposed to be engaged by a lift portion of the cam profile at approximately the same time the lift portion of the cam profile moves out of engagement with the first cam follower. Other complex means includes provision of the hydraulic lash adjuster arranged at a free end of the main rocker arm to reduce valve clearance to zero. Another known complex mechanism includes provision of driving mechanism configured with an output straight-line displacement driving force. Therefore, the objective of the present invention includes simplification of the variable valve timing mechanism to achieve precise valve lifting at a wide operating speed range of the internal combustion engine.
[022] Hence, it is an object of the present invention to overcome all the above stated and other related problems existing in the prior arts, with respect to valve deactivation system at a wide operating speed ranges of the vehicle as well as other problems of known art.
[023] Another objective of the present invention is to provide ease of operation in opening plurality of valves of the engine simultaneously.
[024] Another objective of the present invention is to provide a simplified cam and rocker mechanism in a compact arrangement wherein plurality of cam lobes can interact with plurality of rocker arms at the same time.
[025] Another objective of the present invention is to prevent rocker arm assembly and the cam shaft assembly to rotate freely and ensuring that rocker arm assembly and the cam shaft assembly operate in a controlled manner as per desired degree of movement.
[026] Another objective of the present invention is to provide an optimal force on the rocker shaft to achieve optimum stress which can cause the opening and closing of the engine valve without any hindrance.
[027] The present subject matter provides an improved valve lifting system for an internal combustion engine. The valve lifting system comprising: a rocker assembly, a camshaft assembly and an actuator assembly. The rocker assembly includes a rocker shaft and plurality of rocker arms. The plurality of rocker arms are mounted on a rocker shaft. The camshaft assembly includes plurality of cam lobe and plurality of cam lobe are mounted on a camshaft. The actuator device, includes an actuator and a drive pin.. The camshaft assembly being operatively connected to the rocker arm assembly. The drive pin is disposed on the rocker arm assembly at a predetermined angle from an axis of the rocker shat. In an embodiment, the drive pin is perpendicular to the axis of the rocker shaft.
[028] As per an aspect of the present invention, the rocker shaft assembly being disposed in the internal combustion engine. The internal combustion engine includes a combustion chamber, plurality of inlet valve and plurality of exhaust valve. The plurality of inlet valve being configured to permit a fuel mixture to pass to the combustion chamber. The plurality of exhaust valve being configured to permit an engine exhaust to pass from the combustion chamber of the internal combustion engine.
[029] As per an aspect of the present invention, the drive pin operatively engages and disengage with the plurality of rocker arm of the rocker arm assembly after an activation input from the activator is passed to the drive pin.
[030] As per an aspect of the present invention, the plurality of rocker arm includes a slot for engagement of the drive pin.
[031] As per an aspect of the present invention, the plurality of rocker arm includes a first rocker arm and a second rocker arm and where the second rocker arm is connected to plurality of inlet valves of the internal combustion engine.
[032] As per an aspect of the present invention, the plurality of cam lobe includes a first cam lobe and a second cam lobe. The second cam lobe being configured to operatively engage the second rocker arm during low and revolutions per minute of the internal combustion engine.
[033] As per an aspect of the present invention, the plurality of cam lobe includes a first cam lobe and a second cam lobe. The first cam lobe being configured to operatively engage the first rocker arm during high revolutions per minute of the internal combustion engine. The first cam lobe lifts the first rocker arm and the first rocker arm engages with the drive pin. The first cam lobe, the first rocker arm, the drive pin and the second rocker arm mechanically operate as an integrated unit for opening and closing of plurality of valves of the internal combustion engine.
[034] As per an aspect of the present invention, the drive pin being disposed perpendicular to the rocker shaft.
[035] As per an aspect of the present invention, the drive pin being 80 degree to 110 degree from a rocker shaft axis.
[036] As per an aspect of the present invention, the actuator device includes a supporting portion for supporting the drive pin from an upper end of the drive pin.
[037] As per an aspect of the present invention, the drive pin is connected to a compression spring and the compression spring aids in retraction of the drive pin towards the actuator device during disengagement of the drive pin from plurality of rocker arm of the rocker arm assembly.
[038] As per an aspect of the present invention, the first cam lobe being is engaged with the first rocker arm through a torsion spring during a wide range of engine speeds
[039] In accordance with the present configuration, one of the advantages is that provision of first rocker arm and the second rocker arm ensures that precise valve opening and closing is achieved during both low and high speeds. Also, during low load conditions and high load conditions the first rocker arm and the second rocker arm operate in high lift conditions and low lift conditions.
[040] In accordance with the present configuration, one of the advantages is that a simplified variable valve timing is achieved in comparison to the existing mechanisms. The provision of an aligned drive pin with the first rocker arm and the second rocker arm ensures that the first rocker arm, the second rocker arm, the drive pin and the first cam lobe act as an integrated unit. This results in quick movement of valve in high speed and high load conditions.
[041] In accordance with the present configuration, one of the advantages is that plurality of intake valves can be operated simultaneously. This results in high performance and better fuel efficiency.
[042] The present subject matter is further described with reference to accompanying figures. It should be noted that the description and figures merely illustrate the principles of the present subject matter. Various arrangements may be devised that, although not explicitly described or shown herein, encompass the principles of the present subject matter. Moreover, all statements herein reciting principles, aspects, and examples of the present subject matter, as well as specific examples thereof, are intended to encompass equivalents thereof.
[043] The foregoing disclosure is not intended to limit the present disclosure to the precise forms or particular fields of use disclosed. As such, it is contemplated that various alternate embodiments and/or modifications to the present disclosure, whether explicitly described or implied herein, are possible in light of the disclosure. Having thus described embodiments of the present disclosure, a person of ordinary skill in the art will recognize that changes may be made in form and detail without departing from the scope of the present disclosure. Thus, the present disclosure is limited only by the claims.
[044] Additionally, all numerical terms, such as, but not limited to, “first”, “second”, “third”, “primary”, “secondary”, “main” or any other ordinary and/or numerical terms, should also be taken only as identifiers, to assist the reader's understanding of the various elements, embodiments, variations and/or modifications of the present disclosure, and may not create any limitations, particularly as to the order, or preference, of any element, embodiment, variation and/or modification relative to, or over, another element, embodiment, variation and/or modification.
[045] The embodiments of the present invention will now be described in detail with reference to the accompanying drawings.
[046] Figure 1 illustrates a left side view of a vehicle (100), in accordance with an embodiment of the present subject matter. A vehicle (100) comprising a frame assembly (not shown) being disposed inside the vehicle (100). The frame assembly comprising a head tube (not shown) being disposed in a front portion of the vehicle (100). The frame assembly further comprising a main tube (not shown) extending rearwardly downward in the vehicle (100). The frame assembly further supports a front suspension assembly being connected to a front wheel (103). The rear suspension of the vehicle (100) is connected to a rear wheel (106). The front portion of the vehicle (100) is covered by a front cover (102) and a side portion of the vehicle (100) is covered by plurality of side covers (108). A seat (109) is provided above in a middle and a rear portion of the vehicle (100). Also, a step-through portion (111) is provided on the vehicle (100) rearward to the front portion of the vehicle and forward to the middle portion of the vehicle (100). Also, the vehicle (100) is provided with an instrument cluster (110) for the rider to see various vehicle indicators. A head lamp assembly (101) is provided on the front portion of the vehicle (100). On a rearward end of the vehicle (100) a taillamp assembly (107) is provided for disposition of indicating lamps and a tail lamp. An internal combustion engine (not shown) is configured to be disposed beneath the seat assembly (109) in a downward region of the vehicle (100). The internal combustion engine (not shown) is covered by the side covers (108) to protect the internal combustion engine (120) from sideward impacts. In another embodiment, the internal combustion engine (not shown) is deployed in a three or multiwheeled vehicle.
[047] Figure 2 illustrates a front view of the internal combustion engine (105) of the vehicle (100), in accordance with an embodiment of the present subject matter. The internal combustion engine (105) of the vehicle (100) comprises a cylinder head (130) and a cylinder block (120). The cylinder head is mounted on a top region of a cylinder block (120). The cylinder block (120) being covered by a cylinder head cover (not shown). The cylinder block (120) includes plurality of vanes for guiding air around the internal combustion engine (105) for cooling purposes.
[048] Figure 3 illustrates a sectional view of the cylinder block (120) of the internal combustion engine (105), in accordance with an embodiment of the present subject matter. The cylinder block (120) comprising plurality of intake port (123), plurality of exhaust port (124), a combustion chamber (125), plurality of intake valve (121) and plurality of exhaust valve (122). The plurality of intake valve is configured to allow air-fuel mixture pass to the combustion chamber (125) as per the rotational speed of a crankshaft (not shown) of the internal combustion engine (120). The rotational speed of the crankshaft (not shown) of the internal combustion engine (120) is measured in revolutions per minute (rpm).
[049] Figure 4 illustrates an exploded view of a valve lifting system (200) for the internal combustion engine (105), in accordance with an embodiment of the present subject matter. The valve lifting system (200) includes an actuation device (250), a rocker assembly (230) and a camshaft assembly (240). The camshaft assembly (240) includes a plurality of cam lobes (202, 203), plurality of bearings (204,205) and a flange (206). The plurality of cam lobes (202, 203) includes a first cam lobe (202) and a second cam lobe (203). Alternatively, the first cam lobe (202) is also referred as a high lift cam lobe and the second cam lobe (203) is referred as a low lift cam lobe. The rocker assembly (230) includes a rocker shaft (207), a torsional spring (208), a spacer (209), and the plurality of rocker arms (210, 220). The plurality of rocker arms (210, 220) includes a first rocker arm (210) and a second rocker arm (220). Alternatively, the first rocker arm (210) is also referred as a high lift rocker arm and the second rocker arm (220) is also referred as a low lift rocker arm. The plurality of rocker arm (210, 220) is having a roller portion (222) which engages with a plurality of cam lobe (202, 203). Also, the plurality of rocker arm (210, 220) have a tip portion (221) which engages with valves (not shown) of the internal combustion engine (not shown). Additionally, plurality of rocker arm (210,220) is provided a slot (not shown) to accommodate the drive pin (223). The actuation device (250) includes an actuator (225), a supporting portion (224), a drive pin (223) and a spring (226). The actuator (225) enables disposition or engagement and disengagement of the drive pin (223) with the rocker shaft (207) through a push/retraction mechanism.. The spring (226) being a compression spring supports the drive pin (223) for a smooth push/retraction. In an embodiment, the supporting portion (224) being an arc slider. The arc slider ensures support to the drive pin (223) in a predetermined angular range with respect to axis A-A’ of the actuator (225) (shown in fig 5a). The actuator (225) is interchangeably referred as an actuation device. Further, the arc shaped supporting portion (224) provides sufficient offset to the drive pin (223) during engagement of the drive pin (223) with the rocker shaft assembly (230).
[050] Figure 5a illustrates a left side view of valve lifting system (200) in a disengaged position of the driver pin (223), in accordance with an embodiment of the present subject matter. Figure 5b illustrates a sectional view of valve lifting system (200) in a disengaged position of the driver pin (223), in accordance with an embodiment of the present subject matter. For brevity, figures 5a and 5b are described together. As per an embodiment of the present subject matter, the drive pin (223) is abuttingly coupled with the rocker shaft (230) at a predetermined angle Dpa from an axis (AA’) of the actuator (225). The axis (AA’) being perpendicular to the rocker shaft (230). In an embodiment, the predetermined angle Dpa being zero degrees i.e. the drive pin (223) is perpendicular to the rocker shaft (207). The rocker shaft (230) is disposed along a rocker shaft axis (M-M’).
[051] In another embodiment, the drive pin (223) is slightly offset from the perpendicular axis (AA’) when seen along a rotary axis of the camshaft assembly (240). In this configuration, the drive pin (223) being oriented at an angle Dpa ranging between 80 degree to 110 degree from said rocker shaft (207). The drive pin (223) is disposed between the first rocker arm (210) and the second rocker arm (220). During low rpm of the crankshaft (preferably less than 3000 rpm) the speed is considered as low speed and more than or equal to 3000 rpm the engine is considered to be running at a higher speed. During low rpm the one or more intake valve (121) is being operated only through the second rocker arm (220). During low rpm conditions, the first cam lobe (202) of the camshaft assembly (240) is engaged with the first rocker arm (210) and the second cam lobe (203) is engaged with the second rocker arm (220). The second cam lobe (203) engages with the roller portion (222) of the second rocker arm (220) and consequently cause the tip portion (221) of the second rocker arm (220) to engage the one or more intake valve (121). Such condition is also known as low-lift condition.
[052] Figure 6a illustrates a left side view of valve lifting system (200) in an engaged position of the driver pin (223), in accordance with an embodiment of the present subject matter. Figure 6b illustrates a sectional view of valve lifting system (200) in an engaged position of the driver pin (223), in accordance with an embodiment of the present subject matter. For brevity, figures 6a and 6b are described together Fig 6a illustrates a left side view of valve lifting system (200) with the drive pin (223) of the internal combustion engine (105) being in an engaged position, in accordance with an embodiment of the present subject matter. As described above, during low rpm conditions, the relative movement of the one or more intake valve (121) is controlled by only the movement of the second rocker arm (220). However, during high rpm conditions, the movement of the first rocker arm (210) and the second rocker arm (220) combined is necessary to engage the one or more intake valve (121). During high rpm conditions, a second roller portion (222) of the second rocker arm (221) engages with a first roller portion (222’) of the first rocker arm (210) thereby causing a vertical push to the first rocker arm (210) resulting in slight upward movement of the first rocker arm (210). The engagement of the first roller portion (222’) and the second roller portion (222) is achieved by a higher centrifugal force at higher rpms. The first rocker arm (210) causes the drive pin (223) to be engaged in a slot (211). The slot (211) is provided in the plurality of rocker arm (210, 220) to accommodate the drive pin (223). Due to an aligned fitment of the drive pin (223) in the slot (211) of the first rocker arm (210) and the second rocker arm (220) a single integrated rocker arm unit is formed. The single integrated unit includes the first rocker arm (210), the drive pin (223) and the second rocker arm (220). During such conditions, the first cam lobe (202) cause a movement of the first rocker arm (210) and the motion is transferred to the second rocker arm (220) through the drive pin (223). Here, the contact between the second cam lobe (203) and the second rocker arm (220) is temporarily suspended. Such condition is also known as high-lift condition.
[053] Figure 7 illustrates a graphical plot of high-lift condition and low-lift condition, in accordance with an embodiment of the present subject matter. The x axis of the graphical illustration represents the increasing crank angle in degrees and the y axis of the graphical illustration represents the valve lift in millimeters (mm). As per the graphical illustration, a first curve (301), a second curve (302) and a third curve (303) are plotted. The first curve (301) represents the exhaust valve operation. The second curve (302) represents low lift condition operation of the exhaust valve (122). The third curve (303) represents high lift condition operation of the exhaust valve (122). As per the graphical representation, the third curve (303) achieves higher valve lifting when compared to the second curve. This is necessary because the high lift conditions are necessitated only during high rpm conditions. During such conditions, a higher air is required in the combustion chamber therefore higher valve opening is desirable.
[054] In an embodiment, a timing of opening and closing of said one or more inlet valve (121) and said one or more exhaust valve (122) being based on said selective engagement and disengagement of said drive pin (223) of said actuator device (250), said engagement causing a high valve lift above a predetermined rpm threshold of said engine (105) and said disengagement causing a low valve lift below a predetermined rpm threshold of said engine (105).
[055] Fig. 8 illustrates a method for valve lifting. The method is comprising the following steps: At step 301, the second rocker arm (210) of the rocker shaft assembly (230) is coupling with one or more inlet valves (121). At step 302, the rocker shaft assembly (230) and the camshaft assembly (240) receives input about the engine speed. Based on the input of step 302, at step 303, if engine speed is above a predetermined value, and if the engine speed is above predetermined value step 304 is followed. At step 304, lifting of the first rocker arm (220) is achieved with a first cam lobe (20) of a camshaft assembly (240). At step 305, the drive pin (223) is actuated from the actuating device (250). At step 306, the first rocker arm (220) engaged with the drive pin (223) in a slot (211) of the first rocker arm (220) and the second rocker arm (210). At step 307, the first rocker arm (220), the driven pin (223) and the second rocker arm (210) are integrated for selectively opening and closing of one or more inlet valves (121). In an embodiment the drive pin (223) is disengaging from the first rocker arm (220) if engine speed is less than the predetermined value.
[056] The claimed steps as discussed herein are not routine, conventional, or well understood in the art, as the claimed steps enable the following solutions to the existing problems in conventional technologies.
[057] The primary aim of the present invention is to achieve variable valve lifting in an optimal manner. To achieve the stated objective, the present invention provides the drive pin (223) which is selectively engaged and disengaged with the rocker arm assembly (230) based on the engine speeds. During high engine speeds or high lift conditions, the drive pin (223) is engaged with the first rocker arm (210) and the second rocker arm (220) in an integrated manner and cause opening and closing of the one or more inlet valves (121). Whereas, during the low engine speed or low lift condition, the one or more inlet valves are opened or closed only by the force of the second rocker arm (220) and the second cam lobe (203). During low lift conditions, the drive pin is in disengaged condition and consequently, the force of the first rocker arm (210) is selectively prevented in opening and closing of the one or more inlet valves (121).The selectively variable valve lifting thereby achieves an improved combustion and better performance of the IC engine (105). Additionally, the IC engine (105) assembly is kept compact without putting in place a complex mechanism to achieve variable valve lifting.
[058] While the present invention has been shown and described with reference to the foregoing preferred embodiments, it will be apparent to those skilled in the art that changes in form, connection, and detail may be made therein without departing from the spirit and scope of the invention.

List of Reference Numerals:



100: Vehicle
101: Headlamp Assembly
102: Front Cover
103: Front Wheel
104: Transmission Assembly
105: Internal Combustion Engine
106: Rear Wheel
107: Rear Lamp Assembly
108: Side Cover
109: Seat Assembly
110: Instrument Cluster
111: Step Through Portion
120: Cylinder Block
121: Inlet Valve
122: Exhaust Valve
123: Inlet Port
124: Exhaust Port
125: Combustion Chamber
130: Cylinder Head
200: Valve Lift System
201: Camshaft
202: First cam Lobe
203: Second Cam Lobe
204: First Bearing
205: Second Bearing
206: Flange
207: Rocker Shaft
208: Torsion Spring
209: Spacer
210: First Rocker Arm
211: Slot
220: Second Rocker Arm
221: Tip Portion
222: second rocker arm Roller Portion
222’: first rocker arm roller portion
223: Drive Pin
224: Arc Slider
225: Actuator
226: Spring
230: Rocker Assembly
240: Camshaft Assembly
250: Actuation Device
300: Valve Lift and Crank Angle Graph
301: First Curve
302: Second Curve
303: Third Curve
AA’: Axis
P-P’ : Camshaft plane
D-D’: Drive Pin offset plane

M-M’: Rocker shaft axis
,CLAIMS:I/We Claim:
1. A valve lifting system (200) for an internal combustion (IC) engine (105), said valve lifting system (200) comprising:
a rocker assembly (230), said rocker assembly (230) comprising:
a rocker shaft (207); and
a plurality of rocker arm (210, 220), said plurality of rocker arm (210, 220) being rotatably mounted on said rocker shaft (207);
a camshaft assembly (240), said camshaft assembly (240) comprising:
a plurality of cam lobe (202, 203), said plurality of cam lobe (202, 203) being rigidly connected to a camshaft (201), said plurality of plurality of cam lobe (202, 203) being capable of opening plurality of valve (121, 122) of said IC engine (105);
an actuator device (250), said actuator device (250) comprising:
an actuator (225); and
a drive pin (223),
wherein said camshaft assembly (240) being operatively coupled to said rocker arm assembly (230), and
said drive pin (223) being configured to selectively engage and disengage with said rocker arm assembly (230).
2. The valve lifting system (200) for said IC engine (105) as claimed in claim 1, wherein said drive pin (223) being disposed at a predetermined angle (Dpa) from an axis (AA’), wherein said axis (AA’) being an axis perpendicular to a rotary axis of said rocker shaft (230) and being along an actuating axis of said actuator device (250).
3. The valve lifting system (200) for said internal combustion engine (105) as claimed in claim 1, wherein said rocker shaft assembly (230) being disposed in said internal combustion engine (105), wherein said internal combustion engine (105) includes a combustion chamber (125), one or more inlet valve (121) and one or more exhaust valve (122), wherein said one or more inlet valve (121) being configured for permitting a fuel mixture to pass to said combustion chamber (125) and said one or more exhaust valve (122) being configured to permit an engine exhaust to pass from said combustion chamber (125) of said internal combustion engine, wherein a timing of opening and closing of said one or more inlet valve (121) and said one or more exhaust valve (122) being based on said selective engagement and disengagement of said drive pin (223) of said actuator device (250), said engagement causing a high valve lift above a predetermined rpm threshold of said engine (105) and said disengagement causing a low valve lift below a predetermined rpm threshold of said engine (105).
4. The valve lifting system (200) for said internal combustion engine (105) as claimed in claim 1 or claim 3, wherein said drive pin (223) being configured for operatively engaging and disengaging with said plurality of rocker arm (210, 220) of said rocker arm assembly (230), wherein said drive pin (223) engages with said plurality of rocker arm (210, 220) after an activation input from said actuator (225) being passed to said drive pin (223).
5. The valve lifting system (200) for said internal combustion engine (105) as claimed in claim 1, wherein said plurality of rocker arm (210, 220) includes a slot for engagement of said drive pin (224).
6. The valve lifting system (200) for said internal combustion engine (105) as claimed in claim 1, wherein said plurality of rocker arm (210, 220) includes a first rocker arm (210) and a second rocker arm (203), wherein said second rocker (220) being coupled to one or more inlet valves (121) of said internal combustion engine (105).
7. The valve lifting system (200) for said internal combustion engine (105,)as claimed in claim 1, wherein said plurality of cam lobe (202, 203) includes a first cam lobe (202) and a second cam lobe (203), wherein said second cam lobe (203) being configured to operatively engage said second rocker arm (220) low engine speeds, wherein said low engine speed implies revolutions per minute of said internal combustion engine (105) at below pre-determined value.
8. The valve lifting system (200) for said internal combustion engine (105) as claimed in claim 5 and claim 7 wherein said first cam lobe (202) being configured to operatively engage said first rocker arm (210) during high engine speed, wherein high engine speed implies revolutions per minute of said internal combustion engine (105) being above said pre-determined value wherein said first cam lobe (202) being configured for lifting said first rocker arm (210) and said first rocker arm (210) engaging with said drive pin (223), wherein said first cam lobe (202), said first rocker arm (210), said drive pin (223), and said second rocker arm (220) mechanically operating as an integrated unit for opening and closing of said plurality of valves (121, 122) of said internal combustion engine (105).
9. The valve lifting system (200) for said internal combustion engine (105) as claimed in claim 1, wherein said drive pin (223) being disposed perpendicular to said rocker shaft (230) and along actuating axis A-A’ of said actuator device (250).
10. The valve lifting system (200) for said internal combustion engine (105) as claimed in claim 1, wherein said drive pin (223) being 80 degree to 110 degree from a rocker shaft axis (M-M’).
11. The valve lifting system (200) for said internal combustion engine (105) as claimed in claim 1, wherein said actuator device (250) includes a supporting portion (224) for supporting said drive pin (223), wherein a first end of said drive pin (223) being coupled with said supporting portion (224) and a second end of said drive pin (223) being capable of engaging with a slot (211) of said rocker shaft assembly (230).
12. The valve lifting system (200) for said internal combustion engine (105) as claimed in claim 1, wherein said drive pin (223) being engaged with a compression spring (226), wherein said compression spring (226) aids in retraction of said drive pin (223) towards said actuator device (250) during disengagement of said drive pin (223) from said plurality of rocker arm (210, 220) of said rocker arm assembly (230).
13. The valve lifting system (200) for said internal combustion engine (105) as claimed in claim 1, wherein said first cam lobe (202) being abuttingly engaged with said first rocker arm (210), said engagement being through a elastic load applied by a torsion spring (208) during a wide range of engine speeds.
14. A method for valve lifting comprising steps of:
coupling (301), a second rocker arm (210) of a rocker shaft assembly (230) with one or more inlet valves (121);
receiving (302) input by the rocker shaft assembly (230) and a camshaft assembly (240) about an engine speed;
determining (303), if engine speed is above a predetermined value, and if the engine speed is above predetermined value;
lifting (304), a first rocker arm (220) of the rocker shaft assembly (210) with a first cam lobe (20) of a camshaft assembly (240);
actuating (305) a drive pin (223) from an actuating device (250);
engaging (306) the first rocker arm (220) with the drive pin (223) in a slot (211) of the first rocker arm (220) and the second rocker arm (210);
integrating (307) the first rocker arm (220), the driven pin (223) and the second rocker arm (210), for selectively opening and closing of one or more inlet valves (121).
15. The method for valve lifting as claimed in claim 14, wherein drive pin (223) is disengaging from the first rocker arm (220) if engine speed is less than the predetermined value.