jonnycowboy
Legacy Member
actually theres quite a bit of development going on with those magetically-movemented valves, where you can just give a voltage and it'll tell the valve where to go.. main problem right now is how to sense where the valve is and give proper feedback.. the best and fastest (lowest time constant) sensing technology is laser inferometry but with sensors costing 1000-2000$ your 32V v-8 will have 32000-64000$ more in sensors, kinda expensive for an engine, but for one-cylinder 2-valve research engines they work well .
btw ferrari used that valve float to great effect in something called 'ballistic valve' which is basically an early v-tec system where theres a sharp drop on the end side of the cam profile, and at high rpms it dosen't follow the profile due to the inertia of the valve overcoming the weak springs, and so keeping the valve open longer. as long as you model your spring-mass system (pretty easy actually) you can avoid having the valve hit the piston and avoid the hard hit when the valve hits the follower.
Ferrari's next variable valve timing system was instead of using a hydraulic cam gear, each cam profile was varying length-wise (ie looking down the axis of the camshaft) and the camshaft would just move in and out (slideways!) in the journal bearings to as the rpm changed, and voila infinitely variable timing! but i don't know how they got the cam gear not to loose the chain. anybody know?
btw ferrari used that valve float to great effect in something called 'ballistic valve' which is basically an early v-tec system where theres a sharp drop on the end side of the cam profile, and at high rpms it dosen't follow the profile due to the inertia of the valve overcoming the weak springs, and so keeping the valve open longer. as long as you model your spring-mass system (pretty easy actually) you can avoid having the valve hit the piston and avoid the hard hit when the valve hits the follower.
Ferrari's next variable valve timing system was instead of using a hydraulic cam gear, each cam profile was varying length-wise (ie looking down the axis of the camshaft) and the camshaft would just move in and out (slideways!) in the journal bearings to as the rpm changed, and voila infinitely variable timing! but i don't know how they got the cam gear not to loose the chain. anybody know?