Helical camshaft (original) (raw)

A helical camshaft is a type of mechanical variable valve actuation (VVA) system. More specifically it is a camshaft that allows the valve opening duration to be varied over a wide, continuous, step-less range, with all of the added duration being at full valve lift. In this article a “variable duration camshaft” refers to a camshaft with a design that is intended to replace a conventional camshaft in a cylinder head and operate the valves through conventional followers. Further qualifications are: