Variable Swirl Valve Actuator
The intake manifold has a variable swirl valve actuator located at the rear of the intake manifold. The actuator controls a shaft which in turn moves the swirl valves to vary the swirl ratio into one of the intake ports for each cylinder by adjusting the flow rate. The variable swirl valves make sure that the air entering the cylinder is sufficiently turbulent for good fuel-air mixing even at low engine speeds.
The variable swirl valve actuator is controlled by the Powertrain Control Module (PCM). The PCM constantly adjusts the variable swirl valves to vary the flow rate in relation to engine operating conditions.
The PCM outputs a Pulse Width Modulation (PWM) signal to the variable swirl valve actuator motor. An angular position sensor in the motor is provided with a reference voltage by the PCM. The position sensor returns a ground and a signal proportional to the actuator position.