Pneumatic Actuator

Pneumatic Actuator
The cruise control ECU controls the position of the throttle disc by regulating the amount of vacuum applied by the vacuum pump to the pneumatic actuator. The pneumatic actuator is an air tight bellow coupled to the pneumatic pump via a vacuum pipe. The pump evacuates the air inside the bellow and pipe, which collapses the bellow. This pulls on a cable, which moves the throttle disc to the desired position.