Variable valve timing for four-stroke engines
OwnerMichel Baguenainventor
Life of this patent
Estimating the term…
Abstract
A device for internal combustion engines particularly automobile engines, which varies the opening duration and the lift of the timing valves. This variation results from the utilization of all or part of the profile of an alternating cam of which the motion about an axis is provided by rotating main cams which contact rollers carried on the alternating cam, and is transmitted to a roller in contact with the lever which then actuates the valve. The timing is varied by adjusting the position of the roller by means of support arms by which the roller is displaced with respect to the alternating cam and lever.
Claims8
Valve control mechanism for an internal combustion engine, for varying the lift of at least one valve of said engine, and comprising a kinematic chain including:
- main cam means having one driving cam rotating around a first rotation axis which is a fixed axis, for producing an invariable alternating primary movement;
- secondary cam means, consisting of a rocking cam to which said invariable alternating primary movement is transmitted so that said rocking cam produces a valve lift secondary movement for lifting said valve against the action of a return spring, with the help of at least one valve actuating member;
- roller means interposed between and in contact with said valve actuating member and a profile of said rocking cam for transmitting to said valve actuating member said valve lift secondary movement that said roller means receives from said rocking cam;
- and,
- control means allowing to cause a relative displacement between said roller means and said rocking cam for making use of a portion of said rocking cam profile, wherein,
- said rocking cam is a cam oscillating around a second rotation axis and having at least one contact member in contact with said driving cam for transmitting said invariable alternating primary movement from said driving cam to said rocking cam,
- said roller means comprises a roller mounted on a roller axis and which contacts said rocking cam with said roller and said valve actuating member with said roller axis so that said roller receives said valve lift secondary movement from said rocking cam whereas said roller axis communicates said valve lift secondary movement to said valve actuating member;
- and,
- said control means includes support arms which are adjustably fastened about said second rotation axis and present guide grooves in which said roller axis is engaged and guided by its two ends, for changing the relative position between said roller and said rocking cam and thus the valve lift by changing the position of said support arms and thus of said roller around said second rotation axis.
Dependencies are inferred from the claim text.