The N54 and N52KP meet ULEV II requirements for 2007. There are not many
changes to the emission
systems on these engines. The N54 engine has 2 underbody catalysts in addition
to the "near engine" catalysts
already in use from the N52.
The N51 engine, however, is a SULEV II compliant engine which
GENERAL FUNCTION DESCRIPTION FOR FUEL SUPPLY SYSTEMS
Fuel supply systems, spark-ignition engines
Fuel system
The electric fuel pump in the fuel tank generates the pressure in the fuel
system which is set by the pressure
regulator to a specific level.
Tank venting system
The tank venting system is a