User:Pimpachu/Advanced VTEC

Differences from other VTEC's
Honda's advanced VTEC technology departs greatly from its previous incarnations by no longer relying on switching between two sets of lobes on a given camshaft. It, now, only uses a single set of cam lobes, and uses a second set of rocker arms to provide the varying cam profile.

Explanation of patent
Advanced VTEC innocently starts with the standard camshaft and rocker arms; attached as they normally are: with camshaft overhead, and rocker arms pushing down on the poppet valves. The camshaft is surrounded by a partially open drum which has secondary rocker arms attached to it via a pivoting point. These secondary rocker arms, which have a varying depth profile (similar to cams), are directly actuated by the camshaft, in a scissor-like manner. The primary rocker arms are actuated by the secondary (drum attached) rocker arms. The drum will only rotate to advance or retard the position of the secondary rocker arms, to take advantage of their varying profiles. Thus, through varying the position of the drum about its axis, each cam profile is changed to an optimal height for maximum engine performance without sacrificing fuel efficiency.