Variable Valve Timing

(VVT, Variable Valve Timing) is a technology used in automotive piston engines. VVT technology can adjust the overlap time and timing (part or all) of the engine's intake and exhaust systems to reduce fuel consumption and improve efficiency.

The crankshaft drives the camshaft through a timing belt, gear or chain. The profile and position of the cam on the camshaft are usually optimized for a specific engine speed, which usually reduces the engine's performance at low speeds. torque and power at high rpm. VVT technology allows it to change according to engine operating conditions, improving engine efficiency and power.

Extended information

The development history of vvt:

In the late 1950s, Italian FIAT Motors was the first to obtain the patent for variable valve timing and lift used in automobiles, and in In 1980, the Alfa Romeo Spider 2.0L (US Patent 4,231,330), the earliest car using variable valve technology engine, was launched. In 1975, General Motors invented the patented variable valve lift technology in order to reduce automobile exhaust pollution, but it was not put into practical use.

The mechanical VVT system can advance or retard the timing of the intake and exhaust valves. Others like Honda's VTEC technology switch between two sets of cams at different engine speeds. In 1991, Clemson University in the United States invented and patented a more advanced continuously variable valve timing for intake and exhaust valves. After that, BMW Motor Company and the mechanical department of the school became close partners.