Variable valve timing system works
Piston engines typically draw and throttle through a throttle valve that is driven directly or indirectly by a cam on the camshaft. In each intake and exhaust cycle, the cam drives the valve to open (lift) for a certain time (overlap time).
At high rotational speeds, the engine requires more air, but the intake valves may close before the required air is fully entered, causing performance degradation, so the timing of valve opening and closing is important. A continuously open valve will cause the fuel to exit the engine without being burned, which will degrade the performance of the engine and increase exhaust pollution, so the engine idle speed of the game should not be too low. On the other hand, if the cam continues to open the valve for a long time, like in the case of a racing car, problems will occur at lower speeds.
The crankshaft drives the camshaft through a timing belt, gear or chain. The contour and position of the cam on the camshaft is usually optimized for a specific engine speed, which typically reduces the engine's torque and high speed at low speeds. power. VVT technology enables it to change engine conditions and improve engine efficiency and power.