•  The PCM energizes the variable intake air solenoid valve when the engine speed is less than 4,600 rpm, closing the variable intake air shutter valve to enhance the inertia charging effect at the low engine speed range.

•  The PCM blocks energization to the variable intake air solenoid valve when the engine speed is 4,600 rpm or more, opening the variable intake air shutter valve to enhance the inertia charging effect at the high engine speed range.