Fuel/air supply device

A method of controlling an effective calorific value of a fuel/air mixture to be output from a fuel/air supply device comprising a fuel supply arrangement that is designed to convey fuel from a fuel inlet of the fuel/air supply device to a fuel outlet of the fuel/air supply device, and that comprises a fuel compressor designed to take in and pressurize fuel at a position upstream of the fuel outlet of the fuel/air supply device, and the fuel/air supply device further comprising a primary air supply arrangement designed to convey air from an air inlet of the fuel/air supply device to an air outlet of the fuel/air supply device, the method comprising:

• taking a fraction of air flowing through the primary air supply arrangement;
• and
• supplying the air directly to the fuel supply arrangement at a position upstream of the fuel compressor using a secondary air supply arrangement that interconnects the primary air supply arrangement and the fuel supply arrangement by connecting the primary air supply arrangement to the fuel supply arrangement at the position upstream of the fuel compressor, and that includes an air conduit that has a restricted portion at the position of which an area for allowing air to pass through the air conduit is relatively small in the air conduit.