Variable Dynamic Effect Intake (VDI) System

Variable Dynamic Effect Intake (VDI) System:

The Variable Dynamic Effect Intake (VDI) System takes advantage of pressure waves naturally created in the intake air flow by rotor rotation to increase high speed performance and engine efficiency. When a rotor closes its intake port, a pressure wave moves toward the open port of the other combustion chamber, compressing intake air as it travels. At low engine speeds, this extra pressurization has no advantage and the VDI valve remains closed, causing the pressure wave path to be long. At high engine speeds, the VDI valve opens to permit a shortened path for compressed intake air to follow into the open port.

The ECU controls VDI system operation by variously opening and closing a solenoid valve that directs air pressure from the air injection pump to the VDI actuator. Air pressure is used to operate the actuator because engine vacuum is low at high engine speeds. The actuator in turn opens and closes the VDI valve in the intake manifold. The ECU utilizes engine speed and intake air flow inputs to calculate VDI system control.