Overview
This document contains information on:
General
Function requirements
Function
General
The intake port shutoff ensures an engine load-dependent vortex and distribution of air masses in the cylinder. The subsequently optimized combustion improves the exhaust characteristics and engine output.
Function requirements
Engine management ON (circuit 87)
Function
For each cylinder, the following two intake ports of the charge-air distributor are available: The tangential intake port and the spiral intake port. The tangential intake port is permanently open and designed so that the sucked in air runs tangentially to the cylinder. It this enables the cylinder to be filled with air.
The spiral intake port functions as an intake port through its design, i.e. the air flows in a spiral formation around the intake valve. Spiral intake ports each have one metal flap. The flaps are connected to each other via a shaft and are controlled by the combustion engine control unit depending on the characteristics map. Depending on the engine speed and engine load range, the flaps of the spiral intake ports are opened or closed. In the bottom range, they are closed. When changing from partial to full load, the flaps are opened depending on the characteristics map. As a result, a larger air volume flows into the cylinder. As a result of the twisting movement, the flow velocity is also increased and the fuel/air mixture thus swirls more strongly.
In the event of an error or failure of the supply voltage, the flaps in the spiral intake ports are opened mechanically by the return spring.