Controlling the opening and closing of the intake manifold flaps allows the engine to meet air intake requirements across various operating conditions. At low engine speeds, closing the lower intake passage via the manifold flaps reduces the airflow cross-section, thereby increasing airflow velocity; combined with the specific design of the piston crown, this effectively generates a strong intake swirl, which facilitates the formation and atomization of the air-fuel mixture. Conversely, when the engine operates at high speeds (above 3,000 rpm) using a homogeneous mixture mode, the intake manifold flaps open the lower intake passage, increasing the airflow cross-section to allow for greater air intake and boost engine power output.
