BMW X5: Emissions Management
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 meets the 2007
requirements. In addition to
the 5 existing SULEV states of California, New York, Maine, Massachusetts, and
Vermont - four states have
been added for 2007. These states include, Connecticut, Rhode Island, Oregon and
Washington State.
The N51 emissions measures include:
- Secondary Air System with mini-HFM
- Radiator with "Prem-air" coating
- Lower compression ratio (10:1) via modified combustion chamber and
pistons
- Underbody catalyst in addition to "near engine" catalyst
- Activated carbon air filter in air filter housing
- Steel fuel lines with threaded fittings and sealed fuel tank
- Crankcase ventilation system integrated into cylinder head cover
- Purge system piping made from optimized plastic
NOTE: The SULEV II information above is only preliminary and is
accurate as of 8/06.
Additional information will be released as it becomes available.
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Cooling System
The cooling system of the N54 engine consists of a radiator circuit and an
isolated oil cooling circuit. The fact
that there is an isolated oil-cooling circuit ensures that heat is not
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The N52KP and N51 engine continue to use the conventional "manifold
injection" system carried over from the N52. The fuel supply components are also
carried over with regard to the EKP module, fuel pump etc.
Fig. 50: Identifying Fuel Supply System
N54 Engine
The N54 engine uses the new High Preci
Special tools required:
11 4 281
11 4 481
IMPORTANT: Aluminium screws/bolts must be replaced each time they
are released.
The end faces of aluminium screws/bolts are painted blue for the purposes of
reliable identification.
Jointing torque and angle of rotation must be observed without fail (