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BMW
has made 5 and 6-liter engines for the 7
Series and 5-liter engines for the 8
Series model cars. BMW Motorsport also made a 5.6-liter unit for the
850 CSi. All 5-liter 12-cylinder
engines are 2 valve per cylinder units, while the new 6-liter engine has 4
valves per cylinder.
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The latest 7 Series models
with V-12 power are the 760. This DOHC engine has 322.4 Kw / 438.00
BHP @ 6000.00 RPM with torque of Nm / 444.00 Ft-lbs @ 3950.00 RPM. |
The E38
750iL, offered through 2001, was powered by a V-12 of 5.4 liters with
single overhead camshafts and 2 valves per cylinder. The engine's output
was 326 horsepower.
The V-12 powering the new 760Li is a new
design with 6.0 liters of displacement, dual overhead camshafts (per
cylinder bank) and 4 valves per cylinder. Designated the N73, it is also
related to the N62 V-8 engine that powers the two 745 models.
The V-12 configuration has long been
recognized as an ultimate power plant concept, suited for top-class
vehicles. According to BMW, its physics are ideal: 12 cylinders arranged
in a 60° "vee" of two cylinder banks are perfectly balanced; combined with
the relatively even power pulses of so many cylinders, this results in an
extremely smooth propulsion unit.
Direct Fuel Injection
BMW's N73 is the first direct-injected
V-12 engine ever offered in a production automobile, and the first
direct-injected gasoline engine to meet contemporary emission control
standards.
Direct fuel injection means injection of the fuel directly
into the combustion chamber, rather into the intake port as is the norm.
It has been chosen and developed by BMW's power train engineers to boost
power output and fuel efficiency to higher levels than could be achieved
with conventional fuel injection.
BMW's system operates on a
stoichiometrically optimum fuel-air mixture and can be emission-controlled
by conventional, proven 3-way catalyst technology. By contrast, other
direct-injection concepts currently under development in the auto industry
(such as lean-burn or stratified-charge) can achieve greater
fuel-efficiency gains than the concept chosen by BMW, but these depend on
unproven "deNOx" catalyst technology and require sulfur-free fuel, which
is not universally available.
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