The 7 Series is BMW's largest and most expensive car, the ultimate expression of BMW luxury and technology. One might go so far as to say it presents the "state of BMW." Those who purchase 7 Series are typically younger than buyers of competing cars, so BMW, though preserving continuity, sees little value in conservatism. The new car, coded E65, is brim-full of the sort of obsessive engineering excellence and leaps of progress one would expect from BMW, but most interesting are the ways in which it is truly revolutionary.
The most obvious departure is in its styling. Chief designer Chris Bangle decided that, as BMW styling once changed from "shark" to "wedge," it was again time for a new direction in design. The driver interface has been rationalized and vastly simplified through the invention of i-Drive, or "intuitive" drive. The all-new N62 engine is simply amazing. Harmon-Kardon's Logic 7 sound system was developed (and named) for home use, taking the concept of surround sound to new heights, and is integrated into the new 7 Series as could only be achieved when planning for it from the beginning.
The remainder of the car offers such "trifles" as active anti-roll control and active damping, the world's first six-speed automatic transmission, greater use of aluminum structure, and comfort and safety standards ratcheted up several more clicks at every point.
BMW has experimented with new styling directions in the last couple years' show cars. The Z9 and X-Coupe define two extremes of the vision that will give birth to future BMW products. Bangle explained that, 5 years ago, if any BMW stylist had been asked for a concept of the next 7 Series, or virtually any model, it would have been lower, wider and more wedge-shaped than the old one, a look that was arguably destined to become stale.
Today's 7 Series began with three concepts called "avante guardistic," "Sporty" and "luxury," the latter being grand in the Maybach paradigm. What reached fruition was the avante guardistic look, fortified with sporty wheel proportions. Production sizes range from 17 to 19 in., but Bangle said he likes 20-in. wheels best. The new car is both longer and wider by 20cm (7.87 in.), and it's 6cm (2.36 in.) higher than the old. The BMW wedge has been replaced with a balanced shoulder line. The grille is more upright, with a "power bulge" connecting the kidneys and A-pillars. A new stepless door-holding mechanism allows anti-ding trim to be dispensed with. The overall look, Bangle said, has more presence. It is dominating, leading and modern, powerful like an athlete. Where the thin headlights of the old car had the look of a cat crouching, the new lights give the front end upward movement, as if the cat is leaping forward.
The rear, Bangle argues, is a rational solution to engineering requirements. Aerodynamics dictate a relationship between the roof and the rear deck height. The roof height was increased for headroom, yet it was desired to keep the window line sweeping back from the A-pillars as low as possible to give the interior an open, airy feeling. Another European marque solved the same problem with a cut-off "extrusion," a look Chris rejected as terribly unimaginative. The solution worked out for the 7 Series has structural advantages as well as maximizing access to the trunk, which can hold four golf bags full of 46-in. clubs. Whether you love or hate the new styling, BMW's record is of designs that lead aesthetic judgment and age well.
BMW has also made a revolutionary departure in simplifying the driver interface. In 1952, the 502 had 26 control and indicator functions. In 1975, the E21 had a similar count, but thereafter features and functions increased, with the E38 7 Series having approximately 70 functions requiring nearly as many indicators and about 35 control elements. The E65 7 Series vastly increases the number of functions, and future requirements could increase the count beyond 700. Something had to be done to prevent the cabin from looking like a B-52's cockpit.
BMW's answer is i-Drive, or intuitive-Drive. More than a knob, it's a concept, a rationalization of cockpit functions and space. Primary controls, those related to driving the car, are located on the steering column and wheel. Secondary controls, the basics of major cabin systems such as stereo volume control and climate controls, are available at all times on the console. The remaining tertiary functions are accessed through a controller and display, a versatile, upgradeable, software-based interface.
The display is mounted high in the center of the dash so the driver's peripheral vision can be on the road. The controller is a single knob at the end of the armrest, always at hand and large enough to be used blindly. It functions as a button, joystick and rotary dial. Tactile feedback is actively generated rather than mechanical and is tailored to the functions on the screen, reducing the need to take one's eyes from the road. With this system, the number of operating elements is reduced nearly to the figure of 1952.
I found the i-Drive controller to be intuitive. I was able to access many functions with no explanation whatsoever, and a very short briefing enabled me to use all the functions.
Occasionally, having only one control and screen for several functions I was trying to use simultaneously or alternately made navigation a chore. And, having functions available that one isn't likely to imagine on one's own made it possible to get lost. However, getting found was never more complicated than one or two sideways movements of the controller. The solution is to spend 15 to 20 minutes familiarizing oneself with the many functions. I preferred the i-Drive interface to the touchscreens in other luxury vehicles, because my hand was always able to find the controller and my eye was never far from the road.
The i-Drive system has allowed new freedom in interior design, eliminating clutter and the temptation to gadgetry. BMW compares the new 7 Series interior to furniture and architecture, which are more about a style of living than they are a mechanical device. The cockpit and dash are a single element, and the wood that used to be decorative is now used naturally. Traditional ash grain is available, but the simple elegance of Shaker furniture is offered with open-grained black cherry. Luxury is in the look and feel of the materials.
The new 7 Series' optional stereo system, called Logic 7, is the most advanced I have seen. Subwoofers are integrated into the chassis under the front seats, using the rocker panel sections as 20-liter ported enclosures. Logic 7's creator, Dr. David Griesinger, has made a life's work of studying the way the mind hears and interprets sound. He created digital sound processing software methods that go beyond state-of-the-art 5.1 theater standards. Requiring seven speakers plus subwoofers rather than just five, Logic 7 creates a sound stage inside the vehicle, making the mind believe it is in a larger space. To my ears, Logic 7 does exactly what BMW and Harmon-Kardon say it does. It will be truly unusual music that does not sound better through the system.
The remainder of the chassis is nearly as impressive as these parts, but from BMW that's not really surprising. The unibody has 140m of flanges bonded with adhesive prior to welding, giving 15-percent increases in torsional and bending stiffness and the same increase in energy absorption during crashes. The six-speed automatic transmission is 18-percent lighter than the five-speed it replaces. Under the i-Drive concept, there is a PRND stalk on the steering column and shift buttons on the steering wheel. To avoid a gas-guzzler penalty, U.S. models will not feature Steptronic shifting until the sport package and 760Li.
Active roll control, called Dynamic Drive, works by twisting the anti-roll bar hydraulically, providing up to 6 degrees of roll compensation and allowing a maximum of 4 degrees roll at 1g cornering. Up to 0.5 g, there is no body roll at all. Because anti-roll bars can redistribute cornering grip between the front and rear axle, BMW was able to dial in perfect neutrality at lower speeds and gradually change to understeer as cornering loads increase. The active damping system is manufactured by Sachs. Based on a twin-tube damper, a solenoid-controlled valve in the piston functions bi-directionally to make damping whatever the computer wants it to be.
Luxury details include the standard seats, which combine the functionality of the old car's sport and comfort seats. Each of the 85 electric motors in the car (not counting about 50 percent more in the seats) makes exactly the sound it should, as do hydraulic and air movement systems. In most cases, that is no noise at all.
So how does it drive? On Mini-sized Italian roads, often with broken pavement, the big 7 was perfectly controlled and capable at all times. Several of BMW's engineers present expressed both surprise and pleasure that journalists were driving the new 7 Series as if it were a 3 Series. That, in the end, is the genius of BMW: To make cars that drive exactly the way cars should, combining comfort and performance with little compromise between the two.
The EnginesBMW designed two totally new V8s for its flagship car, designated N62, "new" replacing the old M62 V8s. They have all the latest size- and weight-reducing technology such as cast-in-place silicon cylinder liners but the real news is induction, which pairs continuously variable-length intake runners with infinitely variable valve actuation. The intake runners are shaped alternately as a "p" or a "q" to feed the appropriate bank, giving the port a straight shot at the valve. The inner surface of the circular part of the runner is ported to a central plenum via a rotating sleeve. There are two sets of sleeves on counter-rotating shafts, one for each bank. The position of this sleeve can be adjusted to give a resonant length between 8.5 in. and 23.9 in. The principle is the same as opening the valves on a wind instrument to change the resonant frequency. The runners are at maximum length below 3500 rpm. The 236 degrees of movement to reach the shortest length can be swept in less than 1 second.
The real breakthrough is Valvetronic, continuously variable valve actuation. It eliminates the role of the throttle plate-as significant as changing from carburetors to electronic fuel injection. The cam's movement is transmitted to the rocker arm that actuates the valve by a third element, an intermediate follower that floats in the head, captured between its movable fulcrum, the camshaft, and the rocker arm. Rather than pushing up and down conventionally on the primary rocker arm, the cam lobes apply sideways movement to the intermediate follower, which transmits this motion to the rocker arm via a curved ramp. This ramp multiplies the cam's movement by anything from zero to full lift, depending on which portion of the ramp is against the rocker arm. The pivot point of the intermediate follower is at its upper end, where it is pressed by valve-spring pressure against an eccentric shaft. As this shaft rotates, it changes the pivot point of the intermediate follower laterally but not vertically. Thus, the intermediate follower is "rocked" on the camshaft, causing a different portion of the ramp to act on the rocker arm, and hence the valve. The eccentric shaft is actuated by a worm drive, just as a conventional drive-by-wire throttle shaft would be. There are no monster hydraulic pressures nor slapping solenoids. As the intermediate follower rocks around the camshaft, its phasing relative to the camshaft is changed, so VANOS, a well-established BMW technology, is required for Valvetronic to work. These new engines mark the first application of bi-VANOS to a V8.
The foregoing explanation is complicated, because the system is complicated. It took several minutes of watching the system work to understand what was happening, but when I finally did, I achieved a brief moment of Nerdvana.
BMW has accomplished the impossible. Until now, only diesel engines have had no throttle, which has been one of the reasons for their inherent fuel efficiency. Every engineer knows that the throttle decreases efficiency though pumping losses, but until now this has simply been accepted as the cost of doing business with the Otto cycle. By pulling manifold vacuum all the way down the intake stroke, the piston does work that it never gets back. With Valvetronic, the intake valves can be opened to admit just the required charge into the cylinders, then closed. The remainder of the intake stroke, the piston is doing work to expand the gases in the cylinder, but this work is returned to it on the upstroke. The result is a fuel efficiency increase of 10 percent or more under typical driving conditions.
Benefits don't stop there. Because the valves open only 0.5- to 2.0mm under typical light-throttle conditions, the intake charge moves past them at very high speed-the speed of sound, according to Dr. Goschel. This high-speed flow pulverizes the fuel as it enters the chamber, making for a more homogeneous mixture. Valvetronic is superior to existing gasoline direct injection (GDI) technology, because it works with high-sulphur fuels, such as are found in the United States.
Unlike conventional engines, where the intake charge moves past a wide-open valve very slowly, swirl dynamics are maintained at low speeds. Good low-speed combustion dynamics make throttle response with Valvetronic superior even to that of individual throttle butterflies for each cylinder, which eliminate lag that occurs while the intake manifold is filled. The list of wins for Valvetronic is a long one. Torque and efficiency can be maximized at all speeds and load conditions when Valvetronic is combined with variable intake and bi-VANOS, each of which requires very sophisticated controls. Dr. Gfschel calls the present and coming years the "software era" of engine development.
The new 7 Series is not the first application of Valvetronic: It has been available for several months in the 316ti compact in Europe. BMW believes so strongly in the technology that it will eventually be used in every BMW engine. The four-cylinder was redesigned first, so it was the first to receive Valvetronic. We are told that within a year of the first 7 Series reaching customers, a 760Li will be released. Its N73 V12 will be derived from the N62 and will have GDI in addition to Valvetronic-purely for performance, said Dr. Gfschel. We can't hardly wait.
|Capacity ||3600cc |
|Power ||272 bhp @ 6200 rpm |
|Torque ||265 lb-ft @ 3700 rpm |
|Capacity ||4398cc |
|Power ||333 bhp @ 6100 rpm |
|Torque ||332 lb-ft @ 3600 rpm |