They can adjust your seat, operate side window and mirrors, assist braking and make steering more comfortable all at the touch of a button. With as many as 80 electric motors buried inside a family car, we take a look at some novel applications.
Electric motors perform a variety of functions that were formerly consigned to cranks, gears and levers. They are typically found in anything that has an electrical movement or solenoid function – such as window-lifts, fuel pumps, mirror and headlamp adjusters, ABS, clutches, automated manual transmissions, parking brakes and steering systems. The driving force behind market growth is motorists’ insatiable demand for safety, comfort, economy, a clean environment and overall quality of driving.
Opening new doors
The popularity of minivans in Europe, Japan and the US has spurred many innovations, not least power sliding doors. In 2002, Citroen , Fiat , Lancia and Peugeot became the first European manufacturers to offer mass production vehicles fitted with an electric power sliding door.
Dave Gregory, power products marketing manager, Delphi ’s advanced development team, predicts a ‘revolution’ in door-opening designs and technology. “Today, when we think of power sliding doors on a vehicle, we think of a passenger van, but the technology can be applied to all types of closures and all types of vehicles. For example, gull-wing and scissor doors, typically just on luxury sports cars, may be installed on small cars, sedans, trucks and sport-utility vehicles. It’s a matter of providing total vehicle access and finding the best way to do that. By total vehicle access, I mean improved entry and exit. Right now, it’s usually a tight squeeze between seats and the door opening with a conventional two-door vehicle. Imagine opening just one door and easily sliding into the front or the back seat. Fewer doors also mean fewer moving parts and more door, window and vehicle styling possibilities. We may not change the way doors are made overnight, but we want manufacturers to know that we have the know-how to make their innovative designs a reality.”
Delphi is currently the largest supplier of power sliding doors both in the US and in Europe with a market share of 75%. In the US, Delphi has supplied more than 2 million power sliding doors since 1993. The company is expecting further growth in demand for power sliding doors well into the next decade. “Power products are — and will continue to be — customer exciters,” added Gregory. “Once you have experienced them, you expect them, and then you want those features on your next vehicle. Today, most power products are value-added options. As they come to be viewed as not just convenient, but necessary, they will become standard equipment.”
Are we sitting comfortably?
Seats are becoming safer and more comfortable through a multitude of additional equipment, powered by a battery of electric motors. A top-range Mercedes-Benz , for example, has around ten electric motors hidden under each seat – powering the seat lumbar, headrest and recliner. Although the preserve of luxury cars, power adjustable seating systems are gradually permeating down the segments.
With each motor typically weighing in at 16oz, however, that’s a hefty addition for a complete car seat set. Although a multiplex system could eliminate three motors from each seat, the relative high cost of this technology means it won’t appear just yet. Its reliability – compared to stuffing the front seats with standard DC electric motors – is also still in question.
While electric motors are typically used to improve seat comfort and safety, they are also being used to prevent theft. For example, Nissan has developed a simple, low-cost anti-theft system for vehicles in Japan. The vehicle maker has modified the driver’s seat adjustment unit such that the seat can be placed and locked in an extreme forward position encasing the steering wheel, thus making it impossible to drive the vehicle. The system is operated with the touch of a button in vehicles with electrically powered seats. Nissan says the system does not involve extra costs as it makes use of the existing parts.
Losing the handbrake
The need for convenience and the increasing safety requirements, following the more widespread use of power-window units, electronic seat or mirror adjustment and air conditioning, have finally led to development of the electric parking brake (EPB).
Launched in 2002, the BMW 7-Series was the first car to feature an EPB, replacing the hand-brake with a button on the dashboard. The new solution offers a number of benefits; it ensures that the maximum pressure is applied to the wheels, requires no physical effort or maintenance, takes up minimal space and can be programmed in various safety-enhancing ways.
As electric motors proliferate in the car, manufacturers have also developed lighter and more compact units. Bosch , for example, has introduced a new generation of lightweight miniature motors for use in various systems. Its new generation of actuator motors has an installation depth of just 30mm with an armature shaft diameter of 4mm. In addition to using these motors for conventional applications such as seat- and steering column-adjustments functions, they are also being produced for side-window blinds, convertible folding tops and seat belt extenders.