The New BMW 760i Twelve-Cylinder

The New BMW 760i Twelve-Cylinder

The New BMW Twelve-Cylinder Power Unit, Supreme Power without the Slightest Effort.

The twelve-cylinder power unit in a BMW 7 Series luxury performance saloon guarantees a driving and travel experience quite unique in every respect. No other engine offers such an outstanding combination of power and refinement, no other power unit provides the same supreme standard of prestige.
Now these features come out even more clearly, with BMW’s new V12 offering significantly more power and torque compared with their predecessors, optimising engine response and the ongoing surge of power, and further refining the engine’s acoustics. The progress achieved in this way is clearly recognisable right from the start.
These features also stand out clearly from the BMW 750i which, with its modern V8 featuring TwinPower Turbo Technology and High Precision Injection, as such already offers the power and performance of a conventional twelve-cylinder.
Hence, the new V12 maintains the outstanding position of BMW’s twelve-cylinder models also in the new generation of the BMW 7 Series, giving the driver of a BMW 760i and, respectively, a BMW 760Li all the assurance of absolute supremacy in the luxury class. Yet a further point is that the new engines combine the outstanding qualities of a V12 with up-to-date efficiency, offering a level of fuel economy and emission management even better than eight-cylinder models in the same segment as the BMW 7 Series.
By tradition, the twelve-cylinder enjoys a special status worldwide unmatched by other engines of different design and configuration. The twelve-cylinder represents the highest level of competence in engine technology and justifies its outstanding position through qualities only this drive concept is able to offer.
The unique status of the twelve-cylinder as an incomparably powerful and, at the same time, refined power unit is based on a construction and design principle which offers perfect conditions for supreme power and performance achieved without the slightest effort. Benefiting from an angle of 60° between the two rows of cylinders, the V12, in its supreme elimination of vibrations, comes closer to the highest standard conceivable in physics than any other engine.
All components and design features on the all-aluminium engine block are built and constructed for supreme stiffness on minimum weight. Using a closed-deck structure combined with bolts holding the cylinder head down on the floor plate of the crankcase, the engine, to mention just one example, ensures maximum stability on the cylinder liners. Double bolts on the main bearings with an additional connection to the side panels through threaded support bushes and bolts reduce the influence of lateral forces from the crankdrive on the crankcase.
Further components of the engine block serving in typical BMW twelve-cylinder style to reduce vibrations to an absolute minimum are iron-coated aluminium pistons, forged connecting rods assembled through the cracking process, as well as the crankshaft also forged for absolute perfection. This also makes the sound of the engine when idling a very special experience where the driver first has to look at the rev counter to see whether the engine is running at all.
The new V12 power unit comes with 5,972 cc maintaining exactly the same cylinder volume as on the former engine. Displacing 497.7 cubic centimetres per cylinder, the engine therefore offers exactly the right size and dimensions acknowledged by engine specialists as absolutely ideal. Bore of 89 mm/3.50″ and stroke of 80 mm/3.15″ provides a ratio between these two parameters of 0.9, while the compression ratio is a remarkably high 10.0 : 1 quite unusual on a turbocharged power unit.
Introduction of TwinPower Turbo Technology on the twelve-cylinder.
BMW’s new twelve-cylinder comes with a number of special technical features serving to capitalise on the potential it offers through its design principle and basic structure. In particular, this includes the first-ever use on a twelve-cylinder of TwinPower Turbo Technology and ¬High Precision Injection with gasoline injected directly into the combustion chambers.
Featuring this combination of superior technologies already to be admired on BMW’s six- and eight-cylinders, responding sensitively and directly even to small movements of the gas pedal, maintaining a consistent torque curve and offering a level of fuel economy and emission management quite unusual for an engine of this calibre, the new twelve-cylinder again stands out from the competition in every respect.
Thanks to the small cylinder angle of just 60°, the two exhaust gas turbochargers developed specifically for the new V12 fit in compact arrangement on the outside of the two rows of cylinders, each supplying six cylinders with compressed air.
The turbochargers stand out in particular through their unusually good compressor and turbine efficiency – and through their particular position they provide ideal conditions for keeping the pipes between the exhaust manifold and the turbochargers short and straight for ideal flow conditions. Central supply of turbocharger air into the air collector, in turn, helps to optimise both the engine’s acoustics and charge cycle. The exhaust gas manifolds identical on each row of cylinders come in each case with two three-in-one connections geared to the engine’s firing sequence. In combination with the catalytic converters optimised for minimum counter-pressure, this special configuration of the exhaust gas manifolds sets the foundation for outstanding spontaneity in following the gas pedal as well as supreme power and torque coming from the twelve-cylinder.
Peak torque now increased to 750 Newton-metres or 553 lb-ft comes at just 1,500 rpm and is maintained consistently all the way to 5,000 rpm. Compared with the former engine, this means an increase in torque by 25 per cent now developed at an engine speed approximately 2,300 rpm lower.
Engine power is also built up more quickly than on the previous engine, as is borne out by the much steeper power curve leading up to maximum output of 400 kW/544 hp at just 5,250 rpm. On the road, this means performance borne out, for example, by acceleration from a srandstill to 100 km/h in both models in just 4.6 seconds.
Intelligent solution for even more power and supremacy.
The introduction of TwinPower Turbo Technology raises the twelve-cylinder to a level of output and torque a naturally-aspirated power unit would achieve only with much larger displacement. The increase in engine size and weight inevitable in such a case, together with negative effects on the centre of gravity, fuel consumption and the agility of the car, are all avoided most efficiently and intelligently through turbocharger technology.
A further point is that TwinPower Turbo Technology gives the new V12 its unparalleled power and performance characteristics borne out in particular by the superior development of full power and torque right from the start just above idling speed and then maintained over a wide load range.
To ensure sensitive and precise dosage of power at all times, the compressed turbocharger air is cooled by a technically very demanding and elaborate indirect intercooler. This serves to minimise the overall volume of air required and shorten any delay times, again enabling the engine to respond ideally to the driver’s foot on the gas pedal. An additional coolant pump feeds the separate coolant circuit required for this purpose with its air/coolant heat exchanger positioned directly on the intake unit.
The catalytic converters on the new twelve-cylinder come with the most advanced and sophisticated exhaust gas sensors and quickly reach their optimum operating temperature thanks to their special position close to the engine. Efficient treatment of exhaust gases ensures full maintenance of all international emission standards, the BMW 760i and the BMW 760Li fulfilling the EU 5 emission standard in Europe and the ULEV II standard in the USA.
To reduce counter-pressure the exhaust system comes on the underfloor with largely straight pipes and manifolds increased in size to the largest possible diameter. Exhaust flaps around the silencer masterminded by the electronic control unit as a function of engine maps provide exactly the right engine sound precisely geared to current driving conditions. When idling, therefore, the V12 remains absolutely silent, not emitting any noise at all. The same applies to cruising conditions, with only very discreet sound from the engine being emitted to the outside. So it is only at higher engine speeds that the driver receives appropriate acoustic feedback on the development of power, with the engine providing its muscular V12 sound when accelerating fast and under full power. Again, this special sound effect under such dynamic conditions authentically reflects both the capacity of the engine and the intensity of power coming from within the engine compartment, characterising the dynamic qualities of BMW’s twelve-cylinder.
Optimised combustion and maximum efficiency ensured by High Precision Injection.
BMW ¬High Precision Injection is a second-generation direct injection technology serving to optimise the combustion process and use the energy contained in the fuel with maximum efficiency. Piezo-injectors positioned in the middle of the cylinder head allow particularly precise dosage of the fuel injected into the combustion chambers.
In combination with TwinPower Turbo Technology, ¬High Precision Injection is featured in all gasoline engines in the BMW 7 Series. And now, in the new V12 power unit, this technology ensures particularly efficient and clean combustion as the starting point for a level of fuel economy and emission management quite unparalleled in this class of performance.
Opening up to the outside, the piezo-injectors are positioned in the cylinder head between the valves and, as a result, directly next to the spark plugs. They are supplied with fuel through stainless-steel pipes, fuel then being injected into the combustion chambers in finely atomised form at a pressure of up to 200 bar. This system pressure is generated by single-plunge fuel pumps on each row of cylinders and is maintained reliably at all times by short pipes and fuel travel.
The fuel injected in this process spreads out in conical form, thus burning in a particularly smooth and clean process. This, in turn, has a positive effect on engine emissions and sound, the cooling effect of the fuel/air mixture provided by direct fuel injection helping in addition to achieve a higher compression ratio than on a turbocharged engine with manifold injection. The bottom line, therefore, is an even higher degree of engine efficiency generating more power on less fuel.
In their configuration and structure, the cylinder heads largely follow the particular position of the injectors and spark plugs as well as the combustion process provided by ¬High Precision Injection. Short combustion phases optimised for maximum efficiency build up a high level of pressure and temperature requiring optimised cylinder head geometry and an effective flow of coolant. The cylinder head components cast in a gravity process stand out in particular through their very high level of stiffness, while the cylinder head covers are made of aluminium and come with rubber profile seals.
Double-VANOS and volume flow-controlled oil pump for
maximum efficiency.
Again in typical BMW style, the new twelve-cylinder comes with double-VANOS for infinite adjustment of camshaft control timing. This ensures part load running conditions with a high level of residual gas and reduced throttle loss for maximum fuel efficiency.
A further advantage of double-VANOS is its support in giving the engine a particularly direct response. Joined in a thermal process, the camshafts come with forged cams, additional triple cams on the intake side serving to drive the high-pressure fuel pumps. The valves on the exhaust side, in turn, are filled with sodium for optimum cooling and come with chrome-plated shafts.
The supply of oil to the new twelve-cylinder has also been optimised, the volume flow-controlled oil pump operating on individual demand with maximum efficiency: The six-chamber pendulum-slide pump delivers only as much oil as the engine requires at any given point in time under specific driving conditions.
An oil level sensor is integrated in the oil sump made of pressure-cast aluminium. And instead of a manual oil dipstick, an oil level indicator in the instrument cluster also operating while driving informs the driver of the oil level whenever required.
The new twelve-cylinder models in the BMW 7 Series again feature a wide range of technologies for minimum fuel consumption and emissions based on BMW’s strategy of ¬EfficientDynamics. These include Brake Energy Regeneration, electric coolant pumps operating on demand, and the volume flow-controlled oil pump further optimising the balance of load performance and fuel consumption.
With an increase in engine output versus the former models by 22 and an increase in maximum torque by 25 per cent, average fuel consumption in the EU test cycle has been reduced to 12.9 litres/100 kilometres (equal to 21.9 mpg imp) on the BMW 760i and 13.0 litres (21.7 mpg imp) on the BMW 760Li. The emission rating, in turn, is 299 grams and, respectively, 303 grams per kilometre.
The engine coolant system on the new twelve-cylinder excels through consistent integration of all pipes in the crankcase, optimised cross-sections and the surface structure ensuring a maximum heat exchanger function helping to warm up the engine far more quickly than before on the former power unit.
The arrangement of the coolant inlet immediately next to the main inlet duct for supplying oil serves in addition to connect the two media in thermal terms, again helping to warm up engine oil and maintain the ideal temperature at all times.
The flow of coolant is separated on the two rows of cylinders, in each case running diagonally from the rear outside to the front inside. And last but not least, the arrangement of the outlets again helps to consistently spread out and maintain the temperature level over a wide range of engine speed.