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What Is Variable Valve Timing (VVT) and How Does It Work?

Model: (Various brands) Various
Part: Engine

Let’s see how Variable Valve Timing (VVT) works. In a combustion engine, the valves open and close to allow air and fuel in and exhaust gases out. Timing is the precise moment this occurs. In traditional engines, this timing is fixed and determined by the shape of the camshaft. The optimal timing for low revs (for relaxed driving in the city) is different from that for high revs (e.g., for overtaking). VVT solves this problem; it is a system that dynamically varies the timing of valve opening/closing based on engine speed and driving conditions to achieve the best performance in every situation. The video shows how it works; the system relies on a "smart" gear, within which there is a mechanism that allows the camshaft to slide slightly forward or backward relative to the gear's rotation, thereby advancing or delaying the camshaft's rotation, and consequently modifying the timing of when the valves open or close, without altering the operation of the pistons or crankshaft. More advanced systems, like Honda's VTEC or Stellantis' Multiair, also modify how long and how far the valves lift, resulting in even more pronounced performance improvements.

Posted on 6 May 2026 by ScegliAuto

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