Mechanical variable valve actuation system for 2-stroke and 4-stroke engine operations
View Patent ↗The invention relates to a mechanical variable valve actuation (VVA) system for the control and actuation of the valves of an internal combustion engine. The system according to the present invention realizes the control of the valve lift by means of a fixed pivot part for an oscillating rocker suitable to actuate the valve, the oscillating rocker being actuated by means of an eccentric control element.
1. Mechanical variable valve actuation system ( 1 ) characterized in that it comprises a control element ( 2 ) which controls by means of adjustable connection means the lift of at least a valve ( 104 ) of a valve system ( 100 ), said adjustable connection means being a lever connection system which connects said control element ( 2 ) with a driven shaft ( 4 ) and with an oscillating rocker ( 6 ) which engages the valve system ( 100 ), wherein said oscillating rocker ( 6 ) comprises a first ( 5 A) and said second lift profiles ( 5 B) for engaging said valve system ( 100 ).
2. Mechanical VVA system according to claim 1 , wherein said oscillating rocker ( 6 ) oscillates around a fixed part ( 30 ) in an oscillation range which is established by the operative position of said control element ( 2 ), said first ( 5 A) and said second profile ( 5 B) engaging said valve system in function of said oscillation range.
3. Mechanical VVA system according to claim 2 , wherein said control element ( 2 ) establishes a first oscillating range (R 1 ) for which only said first lift profile ( 5 A) engages said valve system ( 100 ) during the oscillation of said oscillating rocker ( 6 ).
4. Mechanical VVA system according to claim 3 , wherein said control element ( 2 ) establishes a second oscillating range (R 2 ) for which both lift profiles ( 5 A, 5 B) engage said valve system ( 100 ) during the oscillation of said oscillation rocker ( 6 ).
5. Mechanical VVA system according to claim 1 , wherein said control element ( 2 ) is an eccentric element.
6. Mechanical VVA system according to claim 1 , wherein said control element ( 2 ) is a linear element.
7. Mechanical VVA system according to claim 1 , wherein said lever connection system comprises five rods ( 3 a , 3 b , 3 C, 3 d , 3 e ).
8. Mechanical VVA system according to claim 7 , wherein each end ( 10 , 20 , 30 , 40 , 50 ) of said five rods ( 3 a , 3 b , 3 C, 3 d , 3 e ) is a pivot part.
9. Mechanical VVA system according to claim 7 , wherein said first rod ( 3 a ) of said five rods has a first end ( 10 ) which is suitable to be moved eccentrically around a centre ( 2 a ) of said eccentric element ( 2 ).
10. Mechanical VVA system according to claim 9 , wherein said second end ( 20 ) of said first rod ( 3 a ) is connected to the first end of a second ( 3 b ) and third ( 3 c ) of said five rods in a knee joint ( 5 ).
11. Mechanical VVA system according to claim 10 , wherein said second end ( 50 ) of said second rod ( 3 b ) is connected to the first end of a fourth rod ( 3 d ), the second end ( 60 ) of said fourth rod ( 3 d ) being the center of rotation of the driven shaft ( 4 ).
12. Mechanical VVA system according to claim 7 , wherein said second end ( 40 ) of said third rod ( 3 c ) is connected to the first end of a fifth rod ( 3 e ), the second end ( 30 ) of said fifth rod ( 3 c ) being a fixed pivot part for the rocker ( 6 ) oscillation.
13. Mechanical VVA system according to claim 7 , wherein said rod ends define a first ( 10 , 20 , 50 , 60 ) and a second ( 10 , 20 , 30 , 40 ) pivot systems by means of which said control element ( 2 ) can modify and control the valve ( 104 ) lift.
14. Mechanical VVA system according to claim 7 , characterized in that said rocker ( 6 ) oscillates around the fixed pivot ( 30 ) the oscillating range of said rocker ( 6 ) being controlled and modified by means of the position of the pivot ( 40 ), the position of the pivot ( 40 ) being determined by the movement of the third rod ( 3 c ) which is moved as a function of the position of the first end ( 10 ) of the first rod ( 3 a ) with respect to the center ( 2 a ) of the eccentric element ( 2 ).