Developments That Can Change Design & Production

Flat Is Better

The title on Tom VanderLaan’s business card is “Manager, Super Integration,Visteon Automotive Systems, Visteon Technical Center.” This makes it fairly clear that VanderLaan and his colleagues in their labs in Dearborn aren’t just thinking about conventional approaches to integration for automotive electronics but are kicking things up several notches.

Their present initiative is what they’re calling the “superintegrated cockpit.” Superlative notwithstanding, this is fundamentally an instrument panel. But not just any IP. It starts with a lightweight magnesium structure. On that base an array of mechanical and electrical components are attached and integrated. Not only is the result said to be ergonomically advantageous compared to what’s ordinarily available, but it also provides weight savings on the order of 25 to 30%. To be sure, the magnesium plays a role in that. But there is something else, too.

Super integration is not just about putting a whole lot of elements (e.g., audio, communications, HVAC, navigation, airbags. . .) together. It is also about howmany of the pieces are being linked. This has led VanderLaan and his colleagues to start develop-ing a resource that is more common in the consumer electronics industry—for things like camcorders and computers—but not typical of automotive. It is called “flat wire.”

This is not to be thought of as a conventional piece of copper wire that’s been drawn through a rectangular die to become flat. VanderLaan explains that the flat wire is a ribbon of polyester material that has encapsulated strands of wire running through it. As he describes it, “It’s like a flexible printed circuit.”

Ordinarily, power is distributed throughout a vehicle with round wires. These wires are bundled together into wiring harnesses. There are numerous wires, terminals and connectors brought together in what is an extremely labor-intensive process. Typically, companies have to chase cheap labor rates to produce the harnesses.

Visteon is not in the wiring harness business. “This allowed us to take a fresh look at ways to conduct electricity around the vehicle,” VanderLaan explains. Their investigations led to flat wire. VanderLaan, prior to joining Visteon, had been in the connector business, so he has familiarity with what he says is an item that has lots of warranty issues associated with it.

A problem, VanderLaan explains, is that when terminals are plugged into connectors in the assembly plant, it is difficult for the assembler to be certain that a complete connection has been made. Using soldered bonding of flat wire strips can eliminate that concern. But VanderLaan admits that automotive assembly plants are set up to handle wiring harnesses and connectors, not to perform operations that are typical of, say, a Panasonic plant.

However, he suggests that as there is greater modularity—such as bringing in an entire cockpit, pre-wired (pre-flat-wired, that is, although he does admit that they’ll still use round wires for such things as connecting to junction boxes)—the flat wire approach has distinct possibilities, especially as the electronic content in vehicles grow (i.e., those wiring harnesses can become increasingly unwieldy and heavy as more wires are added).

“The hard part,” VanderLaan admits, “is if someone places a wiring harness on a table and says, `Replace this.'” From a pure economic standpoint, he acknowledges that wiring harnesses are “extremely cost competitive.” There is an infrastructure in place to make them and to handle them in plants. Flat wire lacks the advantages of the incumbent. One of the challenges that the Visteon personnel are pursing is scaling up the flat wire to automotive-sized capabilities from the comparatively small consumer-item scale devices. Another inhibitor is that flat wire is presently limited to low-current applications; high-current devices—like blowers, for example—still require conventional wire.

But the benefits that flat wire provides can be found in (1) mass reduction and (2) reduced warranty costs due to the minimization of connectors. “Round wire can get you only so far,” VanderLaan says. “If you want to move to the next step…” Go flat.

Let There Be Light

As the number of gizmos and gadgets—from cup holders and map pockets to electrical outlets and entertainment systems, storage systems and video players—in vehicle interiors multiplies, so does the need for illumination. A better-lit interior provides better utility for the consumer and a safer driving environment. But if you look at the average sedan, even the basic controls like the fuel door latch and seat adjustments lie deep within the shadows of the dome light. Even on vehicles that have extra overhead lights or brighter bulbs, illumination far from ideal. Federal-Mogul Lighting Products, however, has a solution it believes is a win-win for both consumers and OEMs alike.

Traditionally, the need to light the interior of the car has been something of an exercise in minimalism for a variety of design and production reasons. Wiring harnesses, sockets and bulbs all add cost and weight to the vehicle, take up increasingly valuable space behind interior panels and headliners, as well as create additional assembly nightmares. These issues become magnified with the burgeoning amount of electronics in vehicles, as electrical drain also becomes an issue. So the obvious solution to the lighting problem would be a way to get more light, better directed, to more places in the vehicle, without adding wires, sockets and bulbs. To that end, Federal Mogul has developed “distributive lighting systems (DLS),” a method by which light from one bulb can be “plumbed” to as many as a dozen different locations.

While the lighting theory of one source-many locations has been around since the `70s, previous attempts to bring it to production failed due to their over-reaching aim of using a single light source for the entire vehicle and reliance on expensive fiber optic cables. Guy Vachon, director of marketing, Federal Mogul Lighting Products, explains that this new approach is much better suited to the reality of the marketplace. Federal Mogul has identified various subsystems—door panels, seats, consoles, IPs, and headliners—and designed DLS to provide all the light for a subsystem from a single bulb, using a combination of fiber optic cables and, more importantly, “light pipes.”

The key to DLS is its thermoplastic light pipe. First, these reflective plastic tubes are much less expensive than fiber optic cables. While they don’t meet fiber optic cable’s performance, light pipes are more than adequate for providing the low levels of interior light needed for most of what Federal Mogul has in mind. It’s not necessary to shine the entire interior with floodlights, just provide very small amounts of illumination for areas of the vehicle that consumers need to interact with.

Take a door panel, for example. It has several different items that need light: power window controls, power lock controls, a map pocket and the door handle. To light all of these with one bulb, a light pipe is injection-molded to perfectly fit the mostly flat backside of the interior panel. It looks very similar to a clear plastic tree branch, with a single bulb housing at its base.

This piece gets snapped into place during assembly (a particularly efficient proposal for those big suppliers that are looking to supply complete interior modules, since this bit of assembly occurs before the door is even present to get into the way). Because the light pipe is rigid, it can be easily handled by automation. This rigidity also helps to reduce the NVH issues associated with flexible wiring. Furthermore, the light pipes don’t occupy any more space than a conventional wiring harness.

In other subsystems, even more functions can be piped to a single light source. Federal Mogul estimates that DLS, fully implemented in each of the subsystems, would reduce the 40 to 60 bulbs in a typical interior to only eight.

Simple

Vehicles are becoming increasingly sensor-centric as devices and systems are installed to provide drivers with an array of advanced capabilities; some—like anti-lock braking—are becoming taken for granted, others—like electronic stability control—are still generally limited to luxury cars.

This proliferation of electronic devices is having at least two financial impacts: (1) the price of the sensors and (2) the cost of installing the sensors in the assembly plant (not just the physical act of assembly, but also of inventory, logistics, etc., etc.).

As for the first point, recognize that yaw sensors used for a variety of systems are originally aerospace technology; if anything is true of aero-tech: it’s pricey. As for the second: automakers and suppliers alike are working modularity in large part to minimize the number of parts that need to be assembled.

Continental General Tire’s Sidewall Torsion Sensor system makes use of something that every car has—tires—in order to provide input to a variety of systems, including ABS and electronic stability control. This approach not only reduces costs compared to implementing conventional sensor systems, but it also simplifies assembly because cars and trucks need tires, so there is no additional steps required for installation.

But what if a system could be developed that provides information about how the vehicle is performing where the rubber—quite literally—meets the road? What if this system took advantage of components that every car has, thereby eliminating the need for handling additional components?

“The tire is fundamentally where everything happens: ride, handling, safety, stopping,” points out Jim Giustino, senior research associate, Continental General Tire (Charlotte, NC). So why not take advantage of the tires? That’s the question that researchers at the world’s fourth-largest tire manufacturing company asked. And the answer that they developed takes the form of what they’re calling the “Intelligent Tire.”

The tire is used to provide data about sidewall deformation that’s picked up by two magnetic field sensors that are mounted to the wheel suspension.

“Wait a minute,” you say. “Sure, everyone has heard of steel-belted radials, but what’s this about `magnetic’ sensors?”

Simple. In fact, so simple that Giustino remarks, “When I started working on this”—some 2-¹/₂years ago—”I wondered, `Why hasn’t this been done a long time ago?'”

What they have done is put ferromagnetic material in the side wall of the tire. (They tried to glue magnets onto tires, but centrifugal forces being what they are…) The powder is polarized in alternating bands around the circumference of the tire. They’re what the sensors detect. The whole package—tire, sensors, processors—is called the “Sidewall Torsion Sensor System” (SWT).

Each tire that Continental General produces is checked for uniformity to assure that it meets static and dynamic performance requirements; when Intelligent Tires are produced, they, too, are run through the tire uniformity optimizer, but with the additional step of having the magnetic signature read, information that is subsequently used to set up the SWT.

Giustino provides a simple analogy about the way the system works. He compares it to a spring-scale used by sportsmen to weigh fish. The weight is based on spring extension. “The tire is like a soft spring,” he says, “a torsional spring: we measure twist rather than stretch.” An algorithm has been developed that uses the measured deformation to calculate the forces (from braking, acceleration and cornering) acting on the tires. This information can then be used for a variety of applications, including ABS, traction control, vehicle stability, adaptive cruise control, brake-by-wire…and even to let the driver know if a tire has deflated.

Continental Teves—the second largest supplier of ABS—is working with Continental General (both of which are owned by Continental AG) on the SWT system.

Giustino admits that the objective is to provide vehicle manufacturers with more than just Intelligent Tires, but entire corner modules. He also acknowledges that because not all manufacturers use Continental brand tires or brakes, it may be necessary to license other companies to produce the technology.