Valvetronic is a designation for BMW engines equipped with a variable valve lift system. It is a system that, combined with variable valve timing, allows changing the position of the camshaft independently of the position of the crankshaft. It can also change the lift and length of time the valve is open.

This technology is used to optimize engine parameters. Thanks to the Valvetronic system, engines achieve higher performance, lower fuel consumption, and lower emissions.

MIVEC (Mitsubishi Innovative Valve Timing Electronic Control System) is a designation for the engines of the automobile company Mitsubishi, equipped with a system of variable valve timing and valve lift.

This valve control system is used to improve the engine's volumetric efficiency, thereby increasing engine performance and reducing fuel consumption and the amount of emissions produced.

OHC timing is a type of valve timing of a piston combustion engine, in which, in addition to the valves, the camshaft is also located in the cylinder head. The designation of this type of distribution is derived from the English name OverHead Camshaft.

Usually, only a rocker arm is inserted between the camshaft(s) and the valve. Thus, The OHC distribution contains a few components, which reduce inertial forces. The disadvantage of this type of distribution is only the more complicated construction of the cylinder head.

Valve timing is a mechanism using valves to control the flow of working gases (air, fuel, exhaust gases) through a piston combustion engine. This is the most common type of mechanical distribution, used mainly in four-stroke internal combustion engines.

The opening of the valves is controlled by the respective cam of the camshaft, which is driven by the crankshaft. In four-stroke engines, the camshaft rotates 2x slower than the crankshaft, because one working cycle of the engine takes two revolutions of the crankshaft.

Variable valve timing, or variable timing distribution, is a technology that allows optimizing the parameters of a four-stroke internal combustion engine, thereby increasing its performance and reducing fuel consumption.

With variable valve timing, it is possible to control the lift, valve opening moment or valve opening time, or a combination of the mentioned parameters, independently of the crankshaft position. However, the valve's control depends on the revolutions, engine load, and other factors.