SFI SYSTEM


  1. OPERATION


    1. The ECM activates the VSV so that the negative pressure acts on the diaphragm chamber of the actuator. This closes the control valve to match the longer pulsation cycle. As a result, the effective length of the intake manifold is lengthened and the intake efficiency in the low-to-medium engine speed range under heavy load and low-to-high engine speed range under low load is improved due to the dynamic effect of the intake air, thereby increasing the power output.

      A019QF5E02

    2. The ECM deactivates the VSV so that atmospheric air is led into the diaphragm chamber of the actuator. This opens the control valve to match the shorter pulsation cycle. When the control valve is open, the effective length of the intake manifold is shortened and peak intake efficiency is shifted. This benefits the high engine speed range under heavy load, thus providing greater output at high engine speeds.

      A019R26E02