Function and characteristics of variable valve

Function and characteristics of variable valve

◆ The valve variable driving mechanism on the engine can be realized in two forms: one is the camshaft and cam variable system, which is to change the valve timing and valve lift through the transformation of the camshaft or cam;The other is a variable valve lifter system. The camshaft and cam do not change during operation, and the valve lifter, rocker arm or pull rod is changed by mechanical force or hydraulic pressure, thereby changing the valve timing and valve lift.

◆ Variable valve means that the valve timing and lift of the engine can be changed according to the driving conditions to improve power performance and fuel economy.

◆ Raising the valves higher (changing the lift), or longer the opening time of valves (changing the timing), can meet the demand and thus increase power. Conversely, at low speeds, it is best to inhale less mixture, which can reduce the lift of the valve or shorten the opening time, thereby saving fuel.

◆ Although the actuators used by various manufacturers are not the same, they basically control the lift or timing of the valve, or control the timing and lift of the valve at the same time, because the intake or exhaust volume of the cylinder mainly depends on valve lift and timing. The variable valve can make the valve intake and exhaust less at low speed, and more intake and exhaust at high speed, so that the combustion is more complete, and it has better effects on power, fuel economy and emission.