Each cylinder has an
identical fuel injection nozzle mounted in the pre-combustion chamber. As
the pressure  wave of injection reaches a nozzle, the needle valve is lifted
against spring  force and fuel exits into the pre-combustion chamber of the
cylinder as a  highly atomized spray. A small amount of fuel travels between
the needle valve  and pintle nozzle, providing lubrication. Two passages inside
the upper half  of the nozzle body allow fuel that has lubricated the needle
valve to exit  into the fuel return system.