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As the use of electric motors in motor vehicles converges with other technologies such as drive-by-wire, stability control, and active suspension, eventually a major paradigm shift in automotive architecture may be required. In preparation for that moment, Siemens VDO is working on something that it calls eCorner, which is a convergence of several technologies into the wheel and hub assembly.

While the centerpiece of the concept is an electric drive motor that's integrated into the hub (clearly intended for use with a fuel cell or series hybrid powertrain), other interesting technologies include an active suspension system and Siemens VDO's electronic wedge brake (EWB) brake-by-wire system. The whole assembly is kept pointed in the correct direction by a steer-by-wire system. Fitting the system at all four corners of a vehicle would enable some rather interesting vehicle dynamics, with the angle of each road wheel and the amount of power applied to each motor being continuously varied to keep the car pointed where the driver intends it to go.

While each of these technologies by themselves aren't necessarily novel, it's certainly interesting to see them bundled as one package. Now, someone just has to take the big leap and put into production a vehicle that uses all this technology.

[Source: Siemens; a hat tip to reader Dan Mohr]

[The press release from Siemens VDO follows]

Siemens VDO engineers are working on plans to integrate the drivetrain, steering, shock absorbers and brakes directly into the wheels of future cars. This concept, called eCorner, is the basis for the ecological "Drive-by-Wire" automobiles, which will become a common sight on roads in 15 years. eCorner replaces the conventional wheel suspension with hydraulic shock absorbers, mechanical steering, hydraulic brakes and, above all, conventional internal combustion engines. For car owners, eCorner translates into improved fuel mileage, more safety and greater convenience. eCorner provides designers with all new freedom to create future cars with an electric drivetrain and electronic control.

There are enormous requirements placed on tomorrow's vehicles. In the future, it will be vital to be as thrifty as possible with every drop of crude oil, making it necessary to find alternatives to large conventional internal combustion engines. As a result, Siemens VDO projects the traditional engine architecture will be replaced by electric wheel hub motors, which act directly on the wheels to accelerate the car. The four independently operating wheel hub motors will offer extremely dynamic driving on the future highway. The possible elimination of the internal combustion engines burning gasoline or diesel fuel will reduce emissions and will even satisfy the extremely strict laws being anticipated in the future. The Siemens VDO eCorner will make it possible to develop Drive-by-Wire vehicles on which the drivetrain, steering and brakes provide common support for the driver in critical driving situations, thus helping to avoid potential accidents.

The intermediate hybrid motors step
Although Siemens VDO will continue to invest in optimization of conventional internal combustion engines in an effort to completely exhaust their potential, the perspectives for the future are even more important. "Hybrid drives are only an intermediate step along the path to future propulsion solutions. We consider the electric motor to be the actual long-term drive solution for fulfilling even the most stringent emission laws of the future", stated Dr. Klaus Egger, Group Vice President of Siemens VDO Automotive.

eCorner combines drivetrain, steering, shock absorbers and brakes
In the future, car wheels will take on a different appearance than today's familiar steel or mag wheels. With eCorner, a tire containing a sensor (Tire Guard) for monitoring the inflation pressure will be in contact with the road. Even the wheels' suspension of the future will significantly differ from today's design. While complex mechanical wheel suspension systems with oil-pressure spring elements ensure a comfortable ride for the passengers and permanent, reliable contact with the road, electronic circuits will play an increasingly significant role in the future. Within eCorner, electric motors will take over the task of ensuring contact between wheel and road. With this new suspension, hydraulic steering can be eliminated, giving automakers new degrees of freedom. In the future, each individual wheel can be moved to its own specific steering angle. When the speed is reduced, the wheel hub motors act as auxiliary brakes using a generator effect. The energy reclaimed in this manner can be used to charge the vehicle battery. Finally, in addition to the generator brakes, the electronic wedge brakes (EWB) can decelerate each wheel separately with maximum precision and enormous braking power to match the need of the driving situation.

eCorner's drivers and automobile manufacturers advantages
The change-over from internal combustion engines to eCorner wheel hub motor concept will be enhanced by various aspects, for drivers as well as for automobile manufacturers, such as energy efficiency and the associated emissions. Under optimum conditions, a future full hybrid system utilizes approximately 85 percent of the theoretically available energy. Today's gasoline and diesel engines is even less than 50 percent. Wheel hub motors are projected to use up to 96 percent of the provided electrical energy for vehicle propulsion. This will make it much easier for automobile manufacturers to satisfy emission regulations and while simultaneously offering extremely dynamic vehicles with excellent fuel economy. Integration of various vehicle components into the wheels allows further modularization of future cars: Vehicle manufacturers only will require different drive wheel layouts for equipping highly differing vehicle concepts. Moreover, eCorner has the potential to allow a completely new vehicle design, when the large central engine with all its accessory parts and transmission are eliminated. Driver assistance systems using eCorner for support will offer drivers entirely new possibilities. Cars that can virtually park sideways using pivoting wheels or electronic steering aids and controlled acceleration of individual wheels for better vehicle stabilization in hazardous situations. Finally the costs for car owners will also be reduced: Fewer components and elimination of the hydraulic systems will reduce wear and service complexity.

On the way to eCorner
Siemens VDO believes the electronic wedge brake's start of mass production is an important milestone on the way to eCorner realization. The first car on public roads at the end of this decade with the Electronic Wedge Brake (EWB) will demonstrate the advantages of a completely electric brake system, opening the door for other elements to be integrated into the wheel. The greatest intermediate step toward eCorner will be the integrated corner module. During the next decade, this system will integrate all systems into the wheel with the exception of electronic shock absorbers and electronic steering. The combustion engine won't have to disappear completely for the time being: it will be able to provide the necessary electrical power for flexible long-distance vehicles.

For Siemens VDO, the Siemens AG network of innovation is the most important base for advancing eCorner's required technologies. This allows Siemens VDO's automotive engineers to utilize the experience of electric motor developers in the railroad sector or in the automation engineering field.

With its wide range of mechatronics and electronics products, Siemens VDO also is well equipped for the automotive future. With its modern systems, the automotive supplier will offer its customers ample freedom for optimization of internal combustion engines in the coming years. At the same time, the company is laying the cornerstone for reaching safe and emission-free cars of the future with the development of the eCorner.

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    • 1 Second Ago
      • 8 Years Ago
      You would definately need a force-feedback system for the steering wheel/joystick.

      Since the suspension is active, it can provide a luxury car ride with go-cart handling... unsprung weight will not be much of an issue because the "motorized" suspension can absorb bumps and vertical momentum 100x better than a passive fluid shock absorber (which can only slow suspension movements where the active suspension can actually push back)... the electronic 4-wheel steering can also counteract the increased gyroscopic forces created by the increased rotational mass, so steering could also be quick and sharp (or smooth like a luxury car, easily programmable in software).

      All of this together could vastly improve handling overall because you lessen the effect of bumps throwing the car around and can nearly eliminate suspension rebound (which is a cause of oscillation/fishtailing after a swerve that can send you off your intended course or cause the vehicle to roll), which should improve the effectiveness of stability control for avoiding rollovers.

      Also the 4-wheel drive with independent wheel velocities is much like Acura SH-AWD where it vectors torque to the outside wheel to help yaw the car around tight turns... and it would also be quite effective in snow/mud because there is no delay for a limited slip differential to kick in (usually already after you've lost traction/momentum).

      You could store batteries where all the drive shafts, brake lines, exhaust, transmission, etc. used to go, so the vehicle interior would remain the same size (unlike some hybrids which fill half the trunk with batteries)... and in a series hybrid configuration, the ICE could be much smaller than a traditional layout becuase it would only need to supply average power to charge the batteries (not acceleration power) along with the absense of a transmission. It also allows the flexibility to do away with the ICE in the same vehicle when batteries become cheaper and better (hold longer charge, charge faster, charge more times).
      • 8 Years Ago
      This is similar to a concept that was developed at the MIT Media Lab about three years ago. Will it be possible to do what hey say?
      • 8 Years Ago
      Combine this with and integrated body of advanced composites, drag coefficient of .25 or less and advanced battery technology... and this could be the electric vehicle that wasn't. VERY exciting as a (name your fuel)-electric hybrid.... should be able to get it to do well over 100mpg gasoline equivalent).
      • 8 Years Ago
      I've seen the 'electric-motor-in-wheel' design several times over the years, and I want it to work. My only concern is the unsprung weight of the motor upsetting the handling. The article doesn't mention if the active suspension moves the wheel in anticipation of a bump.
      • 8 Years Ago
      'limited-slip' differentials don't 'kick in'
      a torque sensitive differential works as torque is applied-so before wheel spin.

      a speed sensitive differential-often as a viscous coupling, takes a second or two for maximum torque biasing effect.
      • 8 Years Ago
      Unsprung weight. Yeah, that's the first thing that comes to my mind. But I also think of how durable those components would have to be. When I think of some of the potholes I encounter every day. Hmmm. and then there is snow and mud and such. that stuff sure seems like it would be vunerable.

      Still, I don't want to be a naysayer. I'd rather have the positive vision that kballs has. Keep working on it guys, we will see!