By-Wire Replacing Mechanical Systems
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AN_suppl_051031_4-6.qxd 19.10.2005 19:22 Uhr Page 4 Chassis & Materials By-wire replacing mechanical systems TIM MORAN AUTOMOTIVE NEWS EUROPE y-wire systems can eliminate some of the Bjumble of hydraulic and mechanical links in the car, replacing them with an electric architecture controlled by microprocessors. A big benefit is that by-wire requires fewer mechanical parts. That gives automakers greater flexibility in a vehicle’s design. For example, the driver could be positioned anywhere inside the car. Even in the back seat. Here’s why: Drive-by-wire technology uses sensors to translate steering or braking movements by the driver into electronic signals. Onboard computers interpret the movements and relay them to Steer-by-wire means the end of the mechanical connection between the steering wheel electric motors and actuators connected to and the road wheels. Electronically controlled actuators set the steering angles. the moving parts of the car. The systems respond more quickly than today’s controls Hybrid vehicles including the Toyota and can give feedback to the computer as Prius and Honda Civic Hybrid have Losing the link they operate, allowing the car to deliver introduced drivers to the advantages of Primary suppliers of by-wire solutions: precise performance. regenerative braking, a kind of brake-by- By-wire systems already have replaced wire system that converts forward motion ● Bosch ● Mitsubishi Electric direct links in one area. into stored battery energy. ● Continental ● Motorola “Most cars nowadays don’t have a Shift-by-wire technology is available on ● Delphi ● Siemens VDO mechanical linkage between the accelerator high-end autos such as the Aston Martin DB9 ● ● pedal and the fuel injection system. It’s and Rolls-Royce Phantom, as well as some Denso SKF done electronically, and most people don’t BMW, Mercedes-Benz and Lexus models. ● Johnson Controls ● Toyota even realize there’s no mechanical linkage,” Also, comfort and safety systems such as ● Hitachi ● TRW says Steven Brown, director of North adaptive cruise control, automated parallel ● Magneti Marelli ● Valeo American Programs for SKF Automotive’s parking and steering intervention for lane- ● Magna Steyr ● Visteon drive-by-wire business unit. keeping, such as those shown by Continental Teves at last month’s IAA in Little fanfare Frankfurt, rely on by-wire control of some By-wire adaptation stumbled when While General Motors demonstrated steering and braking functions. promised 42-volt electrical systems failed to drive-by-wire on its Autonomy and Hy-wire Any supplier doing work in the by-wire become an industry standard, but new dual- fuel cell concept cars in 2002 and 2003, more arena will tell you there are obstacles to mass voltage systems offer promise of enough progress has happened with less fanfare in adoption of the technology. The auto industry power for high-force uses such as braking recent years – especially in European-built is used to the highly refined technology and steering. vehicles. Brakes, transmissions and safety currently in place. Also, car buyers are not A European consortium called SPARC – systems are bringing by-wire technology clamoring for a change and some early by- short for Secure Propulsion using Advanced into the vehicle in small steps. wire technology features haven’t sold well. Redundant Control – and organized by Electronic parking brakes such as those Until by-wire systems combine more DaimlerChrysler and Fiat is working on by- on the BMW 7 series, Audi A8 and Renault advantages into a single system, adoption of wire accident-avoiding truck and car Vel Satis are examples. the technology will be gradual. demonstration vehicles. ANE ELECTRIC POWER most common in Europe and integrated electric power STEERING Japan but can also be found in steering.” Continental has the US. Globally, about half of all addressed this need by using new cars are expected to have an electronic control unit to lectric power steering electric power steering by 2010. link its second-generation Eremoves the need for hoses The majority of the new electronic stability control to and pumps, and offers fuel small cars in Europe and its electric power steering. savings over hydraulic steering. Japan now have the Another issue is that electric technology. The 2005 power steering is only starting HOW IT WORKS Volkswagen Passat is the first to have enough power to be A battery-driven electric volume car above the lower- Delphi supplies its column- used in the upper-medium motor provides the drive on the medium segment in Europe to drive electric power steering segment and above. The axle steering system rather than a get the technology. In North to the Opel Meriva. The weight and the associated hydraulic device operated by America, electric power electric motor is mounted on torque loads required to turn the engine. The solution also steering is standard on the steering column (circled). the wheels in bigger cars disconnects the steering Chevrolet Malibu. The would quickly drain the system’s power needs from the technology also is available on relatively high, said Peter battery. engine resulting in better fuel the new Lexus GS and typically Rieth, head of advanced economy than hydraulic is found in hybrid cars. engineering at Continental PRIMARY SUPPLIERS steering in a typical small car. Automotive Systems. As a Delphi, Koyo, NSK, Showa, OBSTACLES result, he said, “OEMs [are] TRW Automotive, Visteon, ZF WHERE TO FIND IT For suppliers, the cost of very keen to have extra Lenksysteme. Electric power steering is electric power steering is still functions when they have – Alex Graham ◆ 4 Automotive News Europe October 31, 2005 AN_suppl_051031_4-6.qxd 19.10.2005 19:22 Uhr Page 6 Chassis & Materials ELECTRONIC STABILITY PLASTIC PARTS CONTROL uppliers are substituting super- S strength plastic for steel in some lectronic stability control helps prevent components such as front-end modules Eskids and swerves that can happen in an and instrument panels. It’s a trend that emergency. This makes ESC especially began in Europe and is finding its way into effective in combating rollover accidents. North American vehicle programs. HOW IT WORKS HOW IT WORKS The electronic control unit at the heart of Injection molded plastic is mixed with the ESC system brakes each wheel glass fibers to create high-strength individually and decreases engine torque to structural frames and carriers for maintain a stable direction of travel. ESC components. These structural parts are continuously monitors key inputs such as stronger than standard plastic parts. yaw rate and wheel speed. The modulator (1) and electronic WHERE TO FIND IT WHERE TO FIND IT control unit (2) are at the heart of Faurecia of France announced in July The overall installation rate in 2004 was Continental’s second-generation 2005 that it won a contract with the Chrysler about 40 percent in western Europe. It took electronic stability control system. group, which includes Chrysler, Dodge and antilock brakes twice as long to achieve The system provides individual wheel Jeep, to make what it calls High Integrated a similar level, according to data from braking to keep a vehicle from sliding Module door systems in the US using a German supplier Robert Bosch. out of control. carrier made with an injection-molded long- A law adopted in August 2005 requires US fiber thermoplastic. The module consists of a regulators to develop standards aimed at little or no cost, we can increase the single structural plastic part that includes preventing rollover crashes. Even without performance of the ESC.” mechanical functions such as the window lift the new law, the US National Highway unit, internal and external handles, speakers Traffic Safety Administration appeared OBSTACLES and electrical harness. In addition, headed toward adoption of an antirollover Consumer and dealer awareness of ESC ArvinMeritor recently introduced what it rule. Automakers also have been increasing remains relatively low, especially in North terms as its Highly Integrated Plastic door installation rates for electronic stability America. As a result, Bosch in particular module, which also uses a thermoplastic control systems in the US. As a result, has put considerable effort into holding composite to replace a steel inner structure. installation rates should grow to about events to raise awareness among 50 percent of all passenger cars in North consumers. ESC systems are increasingly OBSTACLES America by 2009. required to interact with a number of other Although the price of steel is high, the TRW Automotive has cooperated with systems in the vehicle – such as steering, resins used to make high-strength plastics Goodyear to develop ESC that can be linked adaptive cruise control and tires – may cost more per pound than steel. to the characteristics of the tires. New tires increasing the risk of electronics problems. are often fitted with identity tags. Using PRIMARY SUPPLIERS those tags “we can tailor the ESC software PRIMARY SUPPLIERS Faurecia, ArvinMeritor, HBPO (a joint to suit different tires and wheels,” says Phil Advics, Bosch, Continental Teves, Delphi, venture with Hella, Behr and Plastic Cunningham, product business director for TRW Automotive. Omnium), RheTech Inc., Owens Corning. chassis systems at TRW Automotive. “For – Alex Graham – Rhoda Miel, Chaz Osburn CONTINUOUS components align differently, this direction.” DAMPING CONTROL rendering it thicker or thinner In 2004, ZF Sachs provided as needed. A computer continuous damping control ontinuous damping control controls the coil to provide very to 175,000 vehicles. For Cis an electronic system that fast reaction to road inputs 2005, it will supply can adjust the tension in a based on input from sensors about 225,000 shock absorber to create a that monitor body and wheel vehicles. The new more dynamic ride quality for motions. Others, including ZF Ford Galaxy large the vehicle. The technology Sachs of Germany, use a valve minivan will includes the use of magneto- control mechanism for have Ford’s rheological fluid that can be damping.