Bose Suspension


  • Bose Suspension - Front wheels

    Bose Suspension - Front wheels

    Seen here is the Bose suspension setup for the front wheels. The black semicylindrical object is the linear electromagnetic motor — the heart of the system. | March 18, 2010

4 Photos

Bose. Mention that word and music comes to mind — specifically, audio systems for upscale cars, as well as expensive but worth-the-cost systems for the home. Business travelers might even connect that name with noise-canceling headphones that reduce some of the stress of flying. What one doesn't associate with Bose is automobile suspension. But after nearly a quarter-century of steadfast and costly research and development by the audio giant, we're willing to gamble that that will change within the next five or so years.

One might ask why a company that's seemingly rooted in the home/automobile audio system business would delve into an area that is so unrelated to its core business. We were wondering this as well, until Dr. Bose addressed us and made it as crystal clear as the sound reproduction of the company's best car stereos. In addition to being a major player in the audio biz, Dr. Bose has had more than a passing fancy in automotive suspension design, which began in 1957 when he bought a new 1958 Pontiac Bonneville equipped with air suspension. Although that system was primitive and prone to breaking down, Dr. Bose was fascinated nonetheless.

Ten years later, he replaced the Bonnie with a Citro├źn, again because he was intrigued by the use of air suspension. For over a decade, he pondered modern auto suspension design and how he would do it, if he had the resources. Fortunately, he had both the financial and intellectual resources — and in 1980 decided to get to work on his idea. And what was that idea? It was, in a nutshell, the use of electromagnetic technology to provide a luxury car's ride with a sports car's control.

By and large, today's vehicle suspensions use hydraulic dampers (a.k.a. "shock absorbers") and springs that are charged with the tasks of absorbing bumps, minimizing the car's body motions while accelerating, braking and turning and keeping the tires in contact with the road surface. Typically, these goals are somewhat at odds with each other. Luxury cars are great at swallowing bumps and providing a plush ride, but handling usually suffers as the car is prone to pitch and dive under acceleration and braking, as well as body lean (or "sway") under cornering — think Lincoln Town Car.

On the other end of the spectrum, stiffly sprung sports cars exhibit minimal body motion as the car is driven aggressively, as cornering is flat, but the ride quality generally suffers — think Mazda Miata. Yes, there are a number of current vehicles that do a good job of providing an agreeable balance of ride and handling, such as a BMW 5 Series, the C6 Corvette and even the Cadillac SRV SUV. But Dr. Bose's goal was to offer a suspension design that would provide an even smoother ride than a top luxury car (such as the Lexus LS 430 sedan) while simultaneously providing more body control than a top sports car (such as a Porsche 911).

Twenty-four years after making a commitment to this vision, Dr. Bose presented his idea to the automotive press. Admittedly, that's a long gestation period for his "baby," but one that he could afford thanks to the freedom afforded by a privately held company. And we were stunned by this achievement. To say that this technology is the biggest advance in automobile suspension since all-independent design would be an understatement.

So howzit work? At the risk of oversimplifying, the Bose system uses a linear electromagnetic motor (L.E.M.) at each wheel, in lieu of a conventional shock and spring setup. The L.E.M. has the ability to extend (as if into a pothole) and retract (as if over a bump) with much greater speed than a fluid damper (taking just milliseconds, actually). These lightning-fast reflexes and precise movement allow the wheel's motion to be so finely controlled that the body of the car remains level, regardless of the goings-on at the wheel level. The L.E.M. can also counteract the body motion of a car while accelerating, braking and cornering, giving the driver a greater sense of control and passengers less of a need for Dramamine. To further the smooth ride goal, wheel dampers inside each wheel hub smooth out small road imperfections, isolating even those nuances from the passenger compartment. Torsion bars take care of supporting the vehicle, allowing the Bose system to concentrate on optimizing handling and ride dynamics.

A power amplifier supplies the juice to the L.E.M.s. The amplifier is a regenerative design that uses the compression force to send power back through the amplifier. Thanks to this efficient layout, the Bose suspension uses only about a third of the power of a vehicle's air conditioning system. Of course, there are a few other key components in the system, such as control algorithms that Bose and his fellow brainiacs developed over a few decades of crunching numbers. The target total weight for the system is 200 pounds, a goal Bose is confident of attaining.

The net result was simply something that had to be seen to be believed.

As this project began some time ago, the cars Bose used to develop and demonstrate this technology were a pair of Lexus LS 400 sedans that were purchased new in the early '90s. Anyone who has driven or ridden in one of these Lexus flagships can tell you what a nice, soft ride they have. One car had the stock suspension and the other had the Bose system. After we viewed displays of the individual components of the Bose system, the demos commenced.

First, we were brought to a garage where both cars sat side by side on unique "Four Poster" testing machines. Used to put suspension systems to the test, a Four Poster supports each of the car's wheels independently and has the ability to move up and down in varying amounts and speeds, simulating bumps and ruts in the road. Not satisfied with current Four Poster technology, Bose designed its own. After driving a loop on real roads that offered a variety of bumps, ruts and potholes, engineers were able to program that loop into each machine. They also programmed the stock suspension calibrations into the Bose-equipped LS 400, allowing, at the flick of a button, that car to be switched back and forth between standard suspension mode and Bose suspension mode.

After a couple of us carefully got into the Bose car, the engineers started up the Four Posters. At first, the Bose car was set in stock suspension mode, and the bumps, though not harsh, were felt and it was easy to see the car's body bobbing around via mirrors placed off to the side. The other LS 400, the one without the Bose setup, was moving about in exactly the same way, as the Four Posters played out their identical bump track. The engineer then hit the button that put the Bose system in operation and the difference was astounding. Although we could see the wheels (via the adjacent mirrors) moving up and down in concert with the non-Bose car beside us, the cabin was so still that one could drink coffee without spilling any.

Still amazed by this display of physics-defying technology, we moved outside where the two cars were brought out and driven side by side over a series of staggered bumps. The stock car waddled over the bumps, while the Bose car seemingly floated over them. Only the movement of the wheels over the bumps proved that this was not some magic trick worthy of David Copperfield. Next was the handling course, where the cars, again running side by side, went through a slalom course, executed an emergency lane change and came to a quick stop. Where the normal car leaned to and fro when going through the cones and dipped its nose under hard braking, the Bose car remained eerily flat through it all. Again, something we wouldn't have believed had we not seen it for ourselves. To further emphasize the amazing level of body control the Bose system provides, a new Porsche 911 was brought out and run side by side with the Bose Lexus. You guessed it, that world-class sports car leaned more than the Bose car through the slalom (of course, the sway was minimal, but the Bose car had none at all) and showed some nose dive under hard braking (where again, the Bose car showed zilch).

The grand finale was something out of a Matrix-style movie. A two-by-six piece of wood was placed on edge and the Bose car drove toward it at moderate speed and then leapt over the board as elegantly as a cat, touching down softly. Though this wouldn't be something applicable in the real world (then again, we can already envision scofflaws jumping over speed bumps...), it served to show what this great technology was capable of.

The next obvious question was when would we see this suspension incorporated? Dr. Bose stated that within five years the company hopes to have the Bose suspension offered on one or more high-end luxury cars, and thanks to the system's modular design, it shouldn't be much of a problem to install at the factory. No information was provided as far as cost, though we imagine that it would come down as production goes up.

Some may say that spending nearly 25 years on developing an automotive suspension is too long. But for the fortunate few who were able to witness Dr. Bose's invention firsthand, it was obviously time well spent. One could say that this incredible Bose invention is to current automotive suspension architecture what a CD changer is to an eight-track player. How fitting.

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