Many models open the hood, see the engine has the word VVT, has not understood today with you to understand.

(VVT,VariableValveTiming) engine variable valve timing.

It is according to the operation of the engine, adjust the intake (exhaust) amount, and valve opening and closing time, Angle. Make the amount of air into the best, improve the combustion efficiency.

The crankshaft drives the camshaft to rotate through the toothed transmission device, so that the valve will be opened and closed when the action and crankshaft rotation Angle form a certain relationship. The flow of gas will change with the speed of the engine. How to make the cylinder at different speeds can obtain good intake efficiency? The timing of valve opening and closing must be changed. Through the oil pressure device installed at the front of the camshaft, the camshaft can be rotated at some other small angles, so that the intake valve can be opened early when the speed increases.

Variable valve timing mechanism can improve engine performance. Different engine speed requires different valve timing. This is because: when the engine speed changes, due to the intake velocity and forced exhaust gas velocity also changes, so the effect of using airflow inertia to increase intake and promote exhaust during late valve closing will be different. When the automobile engine is running at a low speed, the airflow inertia is small. If the valve timing remains unchanged at this time, part of the intake will be pushed out of the cylinder by the piston, so that the intake volume is reduced, and the residual exhaust gas in the cylinder will increase. When the engine is running at high speed, the air flow inertia is large. If the intake late Angle and valve overlap Angle are increased, the intake volume will be increased and the residual waste gas amount will be reduced, and the engine ventilation process will be perfected.