Peter Gilbert, Audi AG, explains the Audi V6 FSI camshaft technology, which gives five percent better fuel mileage.

According to Audi:

FSI® direct injection technology increases the torque and power of spark-ignition engines, makes them as much as 15 percent more economical and reduces exhaust emissions. In contrast to conventional intake manifold injection on conventional spark-ignition engines, FSI® engines inject fuel directly into the combustion chambers. This technology dispenses with the throttle plate. That ˜unthrottles the engine, reduces heat loss and thus increases output while reducing fuel consumption.

The system uses two charge-air supply modes: stratified charge at partial load and homogeneous operation at full load. In the stratified charge mode, an combustible fuel-air mixture is only produced in a defined zone around the spark plug. The engine management electronics monitor engine load and adjust injection timing, pressure, quantity parameters as well as the air flow inside the cylinder via the air intake channel. At full load, FSI® increases compression as well as engine efficiency and performance.