Siemens VDO is testing a totally redesigned braking system called "Wedge Brakes" - no hydraulics. This is reported to be coming to BMW in 2008. Maybe on the M3??? See picture after article below, from Autoweek.
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"The idea behind the system is not exactly new, with similarities to the arrangement found on horse-drawn carriages from the 18th century, where a wedge was used to bring the wheel to a standstill. But rather than relying on a hardened piece of wood for a binder, the electronic wedge uses state-of-the-art electronics and an innovative wedge-shaped connection to provide the sort of stopping ability that existing hydraulic units cannot match.
Unlike today’s traditional hydraulic brake, which requires the buildup of forces before the caliper is able to grip the disc, the electronic wedge brake uses a series of interlocking triangular teeth that offset between the caliper and the disc. In all, it is claimed to require just one-tenth the energy used by hydraulic braking. A small electric motor pushes the pad toward the rotor by a lateral movement—much like how a watermelon seed can be ejected at high velocity by squishing it between your fingers. The entire system runs on the standard 12-volt electrical system found in most cars.
Really clever, however, is that the kinetic energy of the car automatically increases the braking performance. In theory, the faster you are traveling when the brakes are applied, the more powerful they become. When the pad is applied to the disc, the momentum of the rotating disc draws the pad farther up an interlocking series of wedges, applying greater braking pressure and increasing stopping efficiency.
A series of electric motors push in and pull out at an extremely high frequency, while a torque sensor controls the braking force and keeps the wheels from locking up, thus alleviating the need for a conventional antilock braking system. With each brake unit operating independently from the others, it also means the electronic stability control can be programmed to operate on a much finer calibration, without the typical pulsating effect evident in some cars today.
In tests, a prototype with the wedge brakes regularly required less than half the distance to come to a complete stop than the prototype with the standard brakes, a company official said.
As well as providing greatly improved braking ability, wedge brakes are significantly lighter than today’s most advanced hydraulic units. With fewer moving parts, they also could be more reliable and last longer.
When will we see the new brakes begin filtering through to the road? Sources say the first car with wedge brakes, an Audi, BMW, Mercedes-Benz or Porsche, is planned for launch in 2008."
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"The idea behind the system is not exactly new, with similarities to the arrangement found on horse-drawn carriages from the 18th century, where a wedge was used to bring the wheel to a standstill. But rather than relying on a hardened piece of wood for a binder, the electronic wedge uses state-of-the-art electronics and an innovative wedge-shaped connection to provide the sort of stopping ability that existing hydraulic units cannot match.
Unlike today’s traditional hydraulic brake, which requires the buildup of forces before the caliper is able to grip the disc, the electronic wedge brake uses a series of interlocking triangular teeth that offset between the caliper and the disc. In all, it is claimed to require just one-tenth the energy used by hydraulic braking. A small electric motor pushes the pad toward the rotor by a lateral movement—much like how a watermelon seed can be ejected at high velocity by squishing it between your fingers. The entire system runs on the standard 12-volt electrical system found in most cars.
Really clever, however, is that the kinetic energy of the car automatically increases the braking performance. In theory, the faster you are traveling when the brakes are applied, the more powerful they become. When the pad is applied to the disc, the momentum of the rotating disc draws the pad farther up an interlocking series of wedges, applying greater braking pressure and increasing stopping efficiency.
A series of electric motors push in and pull out at an extremely high frequency, while a torque sensor controls the braking force and keeps the wheels from locking up, thus alleviating the need for a conventional antilock braking system. With each brake unit operating independently from the others, it also means the electronic stability control can be programmed to operate on a much finer calibration, without the typical pulsating effect evident in some cars today.
In tests, a prototype with the wedge brakes regularly required less than half the distance to come to a complete stop than the prototype with the standard brakes, a company official said.
As well as providing greatly improved braking ability, wedge brakes are significantly lighter than today’s most advanced hydraulic units. With fewer moving parts, they also could be more reliable and last longer.
When will we see the new brakes begin filtering through to the road? Sources say the first car with wedge brakes, an Audi, BMW, Mercedes-Benz or Porsche, is planned for launch in 2008."
