Variators
Variator is a continuously-variable speed gearbox, working by friction. Most use cones or a spherical surface (concave or convex) to arrange a friction drive between two elements that may be varied in their effective diameter. Before the introduction of hydrostaic transmmisions most combine harvesters used a type of variator drive using a large V belt and two variable width V pulleys to vary transmission speed and drum speeds.A variator is a device that can change its parameters, or can change parameters of other devices.Often a variator is a mechanical power transmission device that can change its gear ratio continuously (rather than in steps).Variator is a system for varying the valve opening of an internal combustion engine. This allows the engine to deliver high power, but also to work tractably and efficiently at low power.There are many systems for variator , which involve changing either the relative timing, duration or opening of the engine's inlet and exhaust valves.