BMW 7 Series: Powertrain and chassis







Published by Gerald Ferreira Date: May 25, 2012
Categories: BMW, BMW 7 Series

The new BMW 7 Series is poised to strengthen its position even further as the most innovative sedan in the luxury segment. New and comprehensively revised engine variants set new standards in terms of performance and efficiency. All the engines available for the new 7 Series team up with an intelligent eight-speed automatic transmission and distinguish themselves with significantly reduced fuel consumption and emissions.

BMW 750d XDRIVE

The Auto Start-Stop function, Brake Energy Regeneration and the second-generation Driving Experience Control switch with ECO PRO mode offer additional potential for fuel-saving. Carefully optimised suspension and Electric Power Steering for all rear-wheel-drive models also take driving comfort to a new level, while self-levelling air suspension for the rear axle likewise comes as standard on all models.

Alongside the flagship BMW 760i with 12-cylinder powerplant and the entry-level engine in the BMW 730i (not available in all markets), customers can choose from the new six-cylinder in-line unit powering the BMW 740i and the revised V8 petrol engine in the BMW 750i. The six-cylinder diesel engines in the BMW 730d and BMW 740d also offer drivers the combination of increased output and lower fuel consumption. Making its debut, meanwhile, is the new BMW 750d xDrive. Under its bonnet lies the new TwinPower Turbo six-cylinder diesel engine – the world’s most powerful diesel engine of its kind. Rounding off the range is the second-generation BMW ActiveHybrid 7 with new  six-cylinder in-line engine and significantly reduced emissions.

BMW 760i: refined 12-cylinder engine still top of the tree. The V12 engine with BMW TwinPower Turbo technology, direct petrol injection and continuously variable camshaft control represents the pinnacle of the BMW 7 Series engine range – no change there. The all-aluminium powerplant generates output of 400 kW from its 5,972 cc displacement and makes peak torque of 750 Newton metres available as low down as 1,500 rpm. That’s enough to propel the BMW 760i effortlessly from 0 to 100 km/h in just 4.6 seconds and on to an electronically limited top speed of 250 km/h. With average fuel economy of 12.8 litres per 100 kilometres and CO2 emissions of 299 g/km, this most cultured of power merchants achieves unprecedented efficiency for its output class.

BMW 750i: eight-cylinder engine develops more power but burns less fuel.

The revised V8 petrol engine under the bonnet of the BMW 750i is making its debut. The 4,395 cc eight-cylinder powerplant retains the impressively smooth assurance and spirited power delivery of its pre-update days.

However, optimised high-pressure direct injection and reduced charge cycle losses – thanks in the main to the seamlessly variable control of intake valve lift – have pushed its performance potential to a higher level than its predecessor and substantially reduced its fuel economy and emissions. In its latest development stage, the engine generates peak output of 330 kW (+ 10 %) and unleashes peak torque of 650 Newton metres (+ 8.5 %) between 2,000 and 4,500 rpm.

The engine teams up with the eight-speed automatic transmission, allowing the BMW 750i to sprint from 0 to 100 km/h in just 4.8 seconds and progress on to an electronically governed top speed of 250 km/h. The eight-cylinder engine belies its improved performance with better efficiency than ever; with overall fuel consumption of 8.6 litres per 100 kilometres and CO2 emissions recorded at 199 g/km, the BMW 750i trumps its less powerful predecessor by a clear 25 per cent. In the Chinese market, the BMW 750i is powered by a 4-litre variant of the engine offering 300 kW and 600 Newton metres of torque.

BMW 7 Series

BMW 740i: new six-cylinder petrol engine boasts outstanding efficiency.

The 3-litre six-cylinder in-line engine stands out with its majestic power and unparalleled high-revving character. The state-of-the-art powerplant is one of the first wave of highly efficient petrol engines to bring together BMW TwinPower Turbo technology with High Precision Direct Petrol Injection, twin-scroll turbocharging, Double-Vanos variable camshaft timing and Valvetronic variable valve timing. Peak output of 235 kW and a maximum 450 Newton metres of torque on tap as low down as 1,300 rpm make this ultra-refined engine the performance equal of the outgoing BMW 740i. However, fuel economy in the EU test cycle is an impressive 7.9 litres per 100 kilometres while CO2 emissions of 184 grams per kilometre represent a 21 per cent reduction in its predecessor’s output.

BMW 730i: entry-level engine variant with reduced fuel consumption (not available in all markets – including South Africa).

This proven 3-litre straight-six petrol engine develops, as before, 190 kW and maximum torque of 310 Newton metres at 2,600 rpm. Linking up with the new eight-speed automatic transmission allows the BMW 730i to exploit additional fuel-saving potential; average fuel economy stands at 8.6 litres per 100 km, while CO2 emissions of 199 grams per kilometres are 13 per cent below the level recorded by its predecessor working with a six-speed transmission.

BMW 750d xDrive: new range-topping TwinPower Turbo six-cylinder diesel engine with intelligent all-wheel drive (not available in South Africa).

The brand-new top-of-the-line diesel powerplant under the bonnet of the BMW 750d xDrive provides fresh evidence of BMW’s pre-eminence in the area of engine technology. The world’s most powerful six-cylinder in-line diesel engine grabs the headlines with its innovative and unique technology, and imbues the luxury sedan with impressive dynamics and outstanding efficiency.

The remarkable TwinPower Turbo technology at the heart of the six-cylinder unit works with three turbochargers and a further developed common rail injection system for the first time in order to optimise the engine’s output, torque and responsiveness. The precisely coordinated management of the turbochargers ensures that the 3-litre high-performance diesel engine develops imposing pulling power across the full rev range – and all with an exceptionally high level of efficiency.

The first charger starts work at just over idle so the combustion chambers can be supplied at an early stage. At 1,500 rpm a larger high-pressure turbo kicks in to help the engine reach its maximum torque. Finally, the third turbocharger joins the fray at 2,700 rpm and ensures particularly impressive power delivery until maximum revs are reached. Piezo injectors spray the fuel into the combustion chambers at up to 2,200 bar, with three pre-injections, one main injection and four post-injections of fuel during each power stroke ensuring efficient and clean combustion.

This enviable engine technology enables the six-cylinder in-line powerplant to produce maximum output of 280 kW and impressive peak torque of 740 Newton metres from as low down as 2,000 rpm, endowing the BMW 750d xDrive with extraordinary thrust. Indeed, the Sedan races from 0 to 100 km/h in only 4.9 seconds. The engine’s vast reserves of power also give it a compelling elasticity. Equally impressive as its performance capability, however, are the efficiency benefits of the BMW diesel technology on board; the Sedan posts fuel economy of 6.4 litres per 100 kilometres in the EU test cycle, which means CO2 emissions are also suitably low at 169 g/km. Plus, BMW BluePerformance technology enables the new flagship diesel to meet the EU6 exhaust gas standard comfortably ahead of time.

The permanent, electronically controlled all-wheel drive of the BMW 750i xDrive ensures the power from this range-topping diesel finds its way safely onto the road at all times by dividing engine power between the front and rear wheels in response to the situation at hand. The system’s precision and rapid responses help give the Sedan stable and dynamic driving characteristics even under demanding conditions.

BMW 740d: further reduction in fuel consumption and emissions.

The rigorous further development of BMW TwinPower Turbo technology has also given the dynamics and efficiency of the familiar six-cylinder in-line diesel engine a boost. At 230 kW, the maximum output of the 3-litre six-cylinder diesel is five kilowatts higher than its predecessor’s, while peak torque of 630 Newton metres comes on stream at 1,500 rpm. Added to which, thermodynamic optimisations sharpen the diesel model’s responses and enhance its agility. Linking up with the new eight-speed automatic transmission, the more powerful BMW 740d manages to record even lower fuel consumption of 5.7 litres per 100 kilometres to go with CO2 emissions of 149 g/km. That’s a 17 per cent improvement on its predecessor.

BMW 730d: cleanest diesel in the luxury segment, emitting just 148 g/km.

Another round of fuel consumption and emissions reductions sees the BMW 730d building on its position as the world’s most economical luxury sedan with the lowest emissions. Peak output of the 3-litre six-cylinder diesel engine, whose construction mirrors that of the engine in the BMW 740d, has increased by 10 kilowatts to 190 kW. And its maximum torque has also risen to 560 Newton metres. However, average fuel economy of 5.6 litres per 100 kilometres in the EU test cycle and CO2 emissions of just 148 g/km allow it to outperform its predecessor – married to a six-speed automatic transmission – by 17 per cent. Specifying the engine with the optionally available BluePerformance technology equips it to meet the EU6 standard.

BMW xDrive: available as an option for the BMW 750i, BMW 740d and BMW 730d (not for SA market).

BMW xDrive intelligent all-wheel drive makes the BMW 7 Series Sedan an even more attractive proposition. In addition to the typical benefits of all-wheel drive, the electronically controlled xDrive system – which can vary the power distribution between the front and rear wheels with split-second speed – ensures top-class traction, safety and handling, and optimal power management whatever the weather and road conditions. The system has been set up to deliver greater agility and precision through corners as well, offers an ideal combination of dynamism and comfort, and provides the perfect basis for a refined driving experience.

BMW ActiveHybrid 7: second generation with six-cylinder petrol engine.

As BMW continues to push ahead with the development of intelligent hybrid drive systems, the second generation of the BMW ActiveHybrid 7 is set to celebrate its premiere in 2012. The updated model sets itself apart with lower fuel consumption and emissions, as well as innovative auxiliary functions. This latest evolution stage uses a six-cylinder in-line engine displaying impressive high-revving characteristics, torque and efficiency.

The cutting-edge petrol engine with BMW TwinPower Turbo technology is the 235 kW variant of the unit fitted in the new BMW 740i and replaces the eight-cylinder engine used up to now. Other hybrid components include the 40 kW synchronous electric motor, the hybrid-spec eight-speed automatic transmission, a lithium-ion high-performance battery and power electronics underpinning intelligent energy management. The various components come together into a powerful and harmonious whole, giving the new BMW ActiveHybrid 7 exceptional dynamics and an outstanding balance between performance and fuel economy – and not only in relation to its predecessor.

With system output of 260 kW and peak torque of 500 Newton metres, the new BMW ActiveHybrid 7 accelerates from 0 to 100 km/h in just 5.7 seconds. At the same time, the Sedan posts average fuel economy of 6.8 litres per 100 kilometres and CO2 emissions of 158 g/km. That means the more powerful hybrid technology uses some 14 per cent less fuel than a BMW 740i with a conventional drive system.

A host of innovative functions are involved in enhancing the car’s dynamics and achieving the excellent efficiency of the overall system. For example, the electric motor hands the six-cylinder an extra 210 Newton metres of torque through the boost function, should the driver need to nail a quick sprint or call on some hard mid-range acceleration. In addition, Brake Energy Regeneration, the Hybrid Start Stop function, ECO PRO mode with coasting function and proactive analysis – to prepare the car’s drive system in advance for upcoming situations on the road – ensure the available energy is used as efficiently as possible (more details in the “BMW EfficientDynamics” chapter). The new BMW ActiveHybrid 7 can also run purely on electric power. If the hybrid battery has sufficient charge and the driver goes easy on the accelerator, the car can cover a distance of up to four kilometres (just under 2.5 miles) almost silently and without producing any tailpipe emissions. The top speed possible using electric power alone is 60 km/h.

Innovative eight-speed automatic gearbox now fitted as standard.

For the year 2012 BMW is fitting all 7 Series models with the extremely effective eight-speed automatic transmission previously reserved for the BMW 760i, BMW 740d xDrive and BMW ActiveHybrid 7. Its additional ratios allow the gearbox to combine unbeatable shift comfort and efficiency, while at the same time aiding the dynamic qualities of the BMW 7 Series Sedan. With its intelligent control technology, the eight-speed transmission boasts extremely fast shift and reaction times and direct downshift capability. The electronic transmission controller can also alter the shift characteristics as required, to cater either for a more sporty or for a more relaxed, fuel-saving driving style.

Despite a larger overall spread, eight ratios mean that the spacing between them is smaller, so that the optimal ratio is available in virtually all situations. The close ratios deliver refined and powerful acceleration as well as smooth and fuel-efficient low-rpm operation. Altogether, then, as well as providing dynamic acceleration and smooth shifting, the new eight-speed automatic also allows drivers to maintain a very economical driving style.

The chassis: optimised set-up and extended standard specification noticeably enhance comfort levels for the driver and passengers.

Dynamic performance, ride comfort and active safety are again among the stand-out qualities of the BMW 7 Series Sedan in the year 2012. Sophisticated chassis technology plays a key role here, providing the ideal partner for the refinement and power of the drive systems. A host of measures give the ride comfort of the Sedan a noticeable boost. Complementing the optimised chassis set-up – with modified rubber bearings and new dampers – and the self-levelling air suspension for the rear axle, Electric Power Steering is a standard feature of the models with rear-wheel drive. State-of-the-art electronic control systems with likewise retuned software help to enhance the long-distance attributes of the BMW 7 Series Sedan and ensure that the new edition of the car makes travelling on board even more pleasurable in terms of both dynamics and comfort.

Dynamics made even more comfortable: double-wishbone front axle and integral-V rear axle with self-levelling air suspension.

The front axle of the BMW 7 Series Sedan is based on the familiar aluminium double-wishbone construction combining maximum rigidity and minimised weight. The patent-protected integral-V rear axle of the BMW 7 Series Sedan is also made from aluminium. The use of modified ball joints, stiffer hydraulic dampers, new rubber bearings and carefully tuned elastokinematics has allowed the engineers to minimise vibrations and therefore bring about a perceptible improvement in onboard comfort levels. By effectively cutting the link between the road surfaces and the drive system, the rear axle also allows the driver and passengers to enjoy excellent acoustic comfort and impressively low vibrations.

All BMW 7 Series models are now kitted out with high-comfort rear axle air suspension, which keeps the car riding at a constant height no matter what kind of driving conditions it encounters and regardless of the loads you have on board. This automatic self-levelling suspension responds to any change in load by adjusting the suspension at the relevant wheel. This means that only small interventions are required in response to spring movements caused by road imperfections and cornering tilt.

Always on the safe side: the lightweight braking system and advanced electronic control systems.

The compound braking system with lightweight, inner-vented swing-calliper disc brakes provides outstanding deceleration in any situation and brakes the Sedan to a standstill in a very short space of time, even from high speeds. In so doing, the system also offers extremely high resistance to fade as well as unbeatable braking comfort. The braking system is backed up by various state-of-the-art electronic safety systems which are integrated into the Dynamic Stability Control (DSC) package and assist the dynamic performance and active safety of the luxury sedan to equal effect. DSC incorporates the Anti-lock Braking System (ABS), Automatic Stability Control (ASC), Dynamic Traction Control (DTC), Dynamic Brake Control (DBC) and Cornering Brake Control (CBC), along with Start-Off Assistant, brake drying and an electronic limited slip function for the rear differential, which can be activated using the “DSC Off” button.

BMW 7 Series South-Africa

Dynamics and ride comfort to suit the occasion:

Dynamic Damper Control, Dynamic Drive and the Driving Experience Control switch with ECO PRO mode.

The BMW 7 Series is the world’s first car to come with an electronically controlled damping system whose dampers are adjusted at each wheel individually according to the condition of the road surface and driving style. The compression and rebound settings are adjusted continuously and independently from one another. For example, a stiff chassis setting can be combined with comfortable responses to unevenness in the road surface. The damper settings can be pre-set by the driver using the Driving Experience Control switch. Optimised software tuning improves ride comfort while also giving agility an extra boost.

The Dynamic Drive roll stabilisation system available for the BMW 7 Series reduces, among other things, body roll in high-speed corners and under sudden changes in direction. Sensors calculate the amount of body roll and this is then counteracted quickly and precisely by rotary actuators in the front and rear axle stabilisers. The Sedan’s steering behaviour and load alteration effect are also adjusted as required in this way. This system allows drivers to thread the car through corners with even greater agility and precision.

Driving Experience Control switch with ECO PRO mode and extended functions: extra sporty, comfortable or economical at the touch of a button.

The new BMW 7 Series not only sets a new dynamic benchmark for luxury cars, it also raises the bar in the class when it comes to ride comfort. The driver can alter the overall character of the Sedan towards greater sportiness or comfort using the Driving Experience Control switch with ECO PRO mode. The distinction between the different driving modes is now even more pronounced. The Driving Experience Control switch with ECO PRO mode is part of the standard specification for all models, with the exception of the BMW 760i.

Using the Driving Experience Control switch, the driver is able to customise accelerator response characteristics, engine response, power steering characteristics and the Dynamic Stability Control (DSC) thresholds. Added to which, the Servotronic function, Integral Active Steering, the automatic transmission and Dynamic Damper Control are integrated into the system too. Using the simple-to-operate rocker switch on the centre console, drivers can choose between ECO PRO, COMFORT, SPORT and SPORT+ modes. Each of these predefined set-ups activates different settings for the relevant powertrain and chassis components. The clear ground between the various modes means the differences between them are now more easily perceptible. If the Integral Active Steering option has been specified, COMFORT+ mode is also available. This mode gains rear passengers, in particular, another noticeable increase in ride comfort.

Another button allows the driver to change the DSC settings. Selecting TRACTION mode, for example, makes it much easier to pull away on loose surfaces or in deep snow. In this mode, as well as in SPORT+, the Dynamic Stability Control thresholds are raised and Dynamic Traction Control (DTC) is activated. It is also possible to switch off DSC altogether.

The new ECO PRO mode, meanwhile, helps the BMW 7 Series driver to maintain an extra-efficient and economy-conscious driving style. It does this by changing the accelerator mapping so that the same pedal travel delivers less power than in the standard mode. Also in this mode, the transmission control strategy for the automatic gearbox is modified to bring forward upshifts and delay downshifts, while intelligent energy and climate management reduces mechanical power consumption and also the energy consumption of electrical systems such as heated mirrors and seats.

But the biggest factor influencing fuel consumption figures is the driver’s own personal driving habits. That is why electronic systems provide tips and incentives on how to develop a more economy-conscious driving style for the situation at hand. Special displays in the instrument cluster let the driver know by how much the driving range is being extended and indicate his fuel consumption history. In ECO PRO mode, average fuel consumption can be reduced by up to 20 per cent, with a corresponding increase in driving range.
Extended functions include the new coasting mode (with ECO PRO selected), plus proactive analysis of the driving situation and the subsequent advance preparation of the drive components (in the BMW ActiveHybrid 7). Both functions offer additional potential for fuel saving and are described in greater detail in the “BMW EfficientDynamics” chapter.

Premiere: Electric Power Steering included as standard.
All new BMW 7 Series models – with the exception of the xDrive variants – come equipped with Electronic Power Steering (EPS), which uses an electric motor to provide steering assistance. EPS only operates when steering assistance is actually required: no electrical power is consumed during straightline driving or steady-state cornering. Noticeable attributes of this system include not only its high efficiency and low weight, but also high steering precision with good feedback, and comfort-enhancing self-centering and anti-roll characteristics. BMW 7 Series drivers also have the benefit of the steering system’s standard Servotronic function, which has a more direct set-up overall and requires less steering effort.

Integral Active Steering provides maximum agility and comfort.
Also available as an option for BMW 7 Series models with rear-wheel drive is Integral Active Steering, which combines the Active Steering system for the front wheels familiar from other model series with a steering rear axle. The steering angle and power assistance are controlled at both the front and the rear with the help of electric motors. Here, the optimised system control unit processes information on wheel rotation speeds, steering wheel movement, yaw rate and lateral acceleration to ensure optimum steering behaviour for the driving situation at hand. In addition, Integral Active Steering works with a variable steering ratio on the front axle, which makes parking and manoeuvring easier for the driver and enables impressive precision at higher speeds. In COMFORT+ mode, in particular, a new software set-up gives the car noticeably damped responses. This translates into a perception of greater comfort among those on board when changing lanes and driving through corners. Integral Active Steering – which is unique in this configuration – also improves the car’s manoeuvrability and agility in the interests of enhanced ride comfort.