Engineering News 7690

Sport utilities cruise the Detroit Auto Show
Consumer demand for fun, multipurpose vehicles
sparks bold concept introductions

Detroit--All-activity, recreation-utility, global-adventure utility: Call them what you will, but these vehicles share one common element--fun.

Collectively referred to as Sport-Utility Vehicles (SUVs), this relatively new market segment dominated the recent North American International Auto Show. A collection of durable, Tonka-truck-like vehicles pushed sports cars and luxury limos alike out of the spotlight.

About 1.5 million buyers chose SUVs last year, which accounts for approximately 9% of the overall industry, says Lincoln-Mercury Vice President Keith Magee. Automakers are scrambling to stake a claim in the SUV segment, and analysts predict that it could grow to as much as 11% of the market this year.

Versatile space. As early as the Jeeps of the 1940s, sport utilities have derived their appeal from a combination of durability and useful space. New concept vehicles such as Mitsubishi's "Global-Ad-venture Utility System," or GAUS, take this to the ex-treme. At about 14 feet in length, the GAUS' cab-forward design emphasizes interior flexibility. Rear seats travel 900 mm (about 35 inches), or can be removed entirely. Front seats rotate 180 degrees, turning the vehicle into a greenhouse sitting-room when it's not in motion.

In place of conventional vertically hinged doors, the GAUS uses wide horizontal doors on its left side. A hydraulic cantilever system slides the larger upper door over the roof at the touch of a button, and hinges the smaller door out and downward to provide an access step. A semi-trailing independent rear suspension and McPherson struts in front make the GAUS "great for on- and off-road driving," claim Mitsubishi engineers.

Like the GAUS, Subaru's Streega SUV concept uses a four-cylinder, turbo-charged 2.0-l DOHC engine. Citing studies indicating that fewer than 5% of sport utilities ever go off-road, Subaru President George Muller positions the Streega concept as "more car-like than most SUVs." The all-wheel-drive Streega's advantage is its four-wheel inde- pendent suspension and braking, paired with a new microprocessor, according to Subaru.

Wheel-speed sensors and a longitudinal G sensor provide input to the microprocessor to detect wheel slip, allowing engine output and torque to be adjusted. This modified traction-control system manages specific road and friction levels, and if necessary, also applies the brakes for improved safety. The Streega isn't scheduled for production but indicates "where SUVs might be heading in the near future," says Subaru.

Due to be released early this year, the Toyota Recreational Active Vehicle (RAV4) combines passenger-car elements with those of a light off-road vehicle. The four-cylinder RAV4 offers full-time four-wheel-drive and an optional torque-sensing limited-slip rear differential.

Mercury's answer to SUV demand, the Mountaineer, joins the fray just as several other automakers debut a first SUV. Due to be introduced this spring, the Mountaineer offers optional all-wheel drive, dual airbags and standard ABS.

Under normal driving conditions, a transfer gear box delivers 65% of the engine power to the rear axle and 35% to the front axle. A viscous coupling in the transfer case increases torque to either axle, depending on road conditions.

Upscale. Automakers known for luxury sedans are now eager to produce deluxe SUVs. "Market research reveals that a large percentage of luxury-car owners intend to purchase an up-scale SUV for their next vehicle," says Rich Thomas, Acura executive vice president and general manager. Acura's first entry, the SLX, is powered by an all-aluminum 3.2-l, 24-valve, V-6 engine rated at 190 hp.

This sport utility offers shift-on-the-fly four-wheel drive and an automatic four-speed transmission with "winter mode" that starts in third gear for improved traction. But it's no simple work-horse. The premium package includes leather interior, heated seats, power moonroof, cruise control, and air conditioning.

Likewise, the new LX 450 marks a first in the SUV market for Lexus. Based on the Land Cruiser platform and powertrain, the LX 450 uses a 4.5-l, twin-cam, six-cylinder engine and will offer the interior appointments of a luxury car. Lexus positions it as a competitor to Range Rover, Ford Explorer, and Jeep Grand Cherokee.

Not to be left out, Mercedes-Benz displayed its "AAVision" design concept: A prototype of the All-Activity Vehicle slated for fall '97. With an emphasis on safety, the AAVision uses ABS and Mercedes' Electronic Stability Program to correct for over- and under-steer. A dual-range transfer gearbox and electronically controlled full-time four-wheel-drive automatically sense wheel slip for traction control.

-- Andrea Baker, Associate Editor

GM becomes first Big-Three automaker to design electric car for mass production

Los Angeles--For the first time in U.S. automotive history, a Big Three carmaker will be mass-producing a zero-emission electric vehicle designed from the ground up for battery power.

The General Motors EV1 accelerates from 0 to 60 mph in 9 seconds, runs up to 80 mph, goes 70 to 90 miles between charges, and takes roughly three hours to recharge, the company says. It will be sold under the Saturn nameplate beginning this fall in Southern California and Arizona, at an estimated price in the mid-$30,000 range.

EV1's number-one design challenge: "Having to make the vehicle very, very efficient, and keeping that in mind in every part of the design," says Bruce Zemke, staff development engineer at General Motors' Electric Vehicle Group. "There's so little energy in lead-acid batteries."

The drive for efficiency led designers to create a car with a 0.19 drag coefficient--"30% less than any other production car in the world," Zemke notes. A conventional Saturn, by comparison, rates over 0.30.

GM engineers used a 137-hp, three-phase ac induction motor to power the car, after deciding that brushless-dc technology was not advanced enough when the EV1 project launched in 1990. The motor is lightweight, with high power density and efficiency of more than 90%.

A regenerative braking system helps extend the EV1's range, GM officials say. As a driver slows the car, the motor turns into a generator, using some kinetic energy to recharge the battery.

The car's inductive-charging system uses a 220V, 6.6-kW charger. The charge port in the front of the automobile is used in conjunction with a paddle-shaped outside device, he explains. The EV1's charge port has two coils that fit on either side of the outer portion. The off-board charger creates an HF ac current, which is then converted to dc to charge the battery. The system is totally encapsulated for safety, he says. "We've even done the charging under water, in an aquarium." Toyota will be licensing the technology, developed by Hughes Electronics and produced by Delco Electronics.

For the EV1, the standard 6.6-kW system is permanently mounted--in the driver's garage, for example, according to Hughes. A 1.5-kW portable charger can plug into standard 110V wall outlets. Southern California Edison also announced plans to open 18 charging stations around Los Angeles by August. The first, opened in January, is in a Wal-Mart parking lot.

Polyamide-imide tips the scale for wafer tips

Sunnyvale, CA--When it comes to handling silicon wafers, high purity becomes an essential ingredient. Even minute impurities can negatively impact process yields.

Thus, the silicon wafers, from which microchips are made, can't be touched by human hands or the oil transferred from fingers would contaminate the wafers. Even gloves cannot be used, because fine dust might get on the wafers.

To solve such handling problems, chip makers use ultra-clean, hand-held vacuum wands to pick up the wafers and transfer them to handling trays. However, the wafers come out of a forced-air oven hot and can have high static charges. The wands must have non-conductive, heat-resistant tips.

H-Square Corp., which makes such wands, met this demanding set of criteria by machining the tips from 3/8-inch-thick Torlon(R) polyamide-imide (PAI) plate. Supplied by the Polymer Corp., Reading, PA, the Torlon PAI retains its high strength and stiffness at temperatures up to 520F. Further, the material has low levels of ionic impurities (sodium, potassium, and iron) that are of most concern.

To accommodate wafers up to eight inches in diameter, H-Square makes the PAI vacuum tips in several different configurations. Basically, the tip has a flat contact surface, which has a vacuum port, and a narrow-diameter hole through its center. The hole runs from the vacuum port to the base of the tip.

A stainless-steel tube on the end of the wand attaches, by a light press-fit, to the hole in the base of the vacuum tip. A metal screw holds the tip in place.

Because of the press-fit design and the mechanical fastener, the PAI tip had to have a high degree of dimensional stability over a broad temperature range. Unfilled Torlon PAI has a low coefficient of linear thermal expansion of 1.7 x 10^-5 inch/inch/F up to 300F.

"We take great pride in offering the most complete range of quality semiconductor-handling equipment," says Howard Hendricsen H-Square president. "That's why we provide the PAI tips, which combine excellent heat resistance, electrical insulation, and cost."

'Jewel Cube' speakers sound like a real gem

Framingham, MA--Bose Corp. believes that when it comes to speakers, good things do come in small packages.

The company's Jewel Cube(TM) speakers measure about 4 x 2 x 3 inches--not much bigger than a cellular flip phone. They comprise part of the Bose Lifestyle(R) 20 music system, which Bose calls its most technologically advanced yet.

A smaller vibrating surface can actually provide better speaker performance, Bose engineers say, because a wider bandwidth can be produced without unwanted frequency response aberrations.

Such small speakers need a very powerful motor structure--the voice coil and magnet. To get this power, Bose uses a magnet made of neodymium iron boron, providing ten times the magnetic energy of a strontium ferrite magnet. This magnet is about the size of a quarter; but, used with a one-inch voice coil, it provides the high-performance motor structure required.

Another innovation is the cone/dust cap. Traditional methods of gluing the dust cap onto the cone don't give the necessary precision for two-inch trandsducers. Bose designed a one-piece cone/dust cap with no adhesive bond for the new speaker system. Tests show the speaker's transducers to be within .50 of 1 dB of each other--an inaudible speaker difference.

"We were looking for the most consistent structure," says Tim Holl, manager of research operations at Bose. "But with such a small cone and a large dust cap, the use of glue as well as the positioning of the two pieces would affect the sound performance consistency. A one-piece cone/dust cap meets our objectives: consistency and wide-range performance."

In order to get needed acoustic output from the tiny speaker, the enclosure is ported. But such a small enclosure calls for a very long port of roughy four inches. So, taking a cue from nature, the Jewel Cube speaker port is wrapped around itself into a nautilus shell shape. "The nautilus port de-sign generates the maximum sound output with the minimum amount of cone excursion down to the lowest frequency produced by the cube (about 190 Hz)," Holl explains.

The cubes are matched with an Acoustimass(R) bass module. The Lifestyle 20 music system retails for about $2,500.

Ford opens VR lab

Detroit--Ford Motor Co.'s new virtual-reality lab hopes to discover how best to use VR in designing automobiles of the future. "There are a number of areas that have a lot of potential," Software Engineer James Korotney told Design News shortly after the center opened.

Among them: interior ergonomics, allowing engineers to test things like the placement of steering wheels for drivers of different heights. Ford is also investigating VR tools for designing engine packaging to check for part interference and engine maintainability.

"There's a lot of concern about accuracy," he admits. For now, Ford engineers are working to validate the tools, checking virtual models with actual prototypes. While engineers are not likely to create their designs inside "virtual worlds" anytime soon, realistic simulations can help engineers narrow their design choices before prototypes are made. In addition, the technology can be useful during design-review meetings, where engineers might meet "inside" a virtual world to consider the merits of a simulated automobile.

Ford recently purchased dVISE and dVS VR software from Division Inc., which will be used with existing VR peripherals, such as the Fakespace BOOM viewer and Virtual Technologies CyberGlove. Much of the VR lab's hardware comes from Silicon Graphics.

"Now it's not a primary tool. It's still in its infancy," Korotney says. "But I think for sure it's going to be an integrated tool."

Computer cranks out a trillion calcs per second

Eagan, MN--Engineers with intensive computing needs may now have the ultimate solution for their technical problems: a new "scalable" supercomputer with peak speeds in excess of a trillion calculations per second.

The new machine, Cray Research's T3E, could be a boon for engineers doing analytical work involving highly repetitive calculations. Such work includes crash analysis, metal stamping simulation, and study of turbulent fluid flow in aerospace and automotive applications.

By lashing together as many as 2,048 microprocessors, the new machine reaches speeds of 1.2 trillion calculations per second. Such speeds enable it to solve large-scale "compute-intensive" problems in hours, rather than weeks. Cray Research officials say the T3E's peak speed operation is comparable to that of 3,000 personal computers, or 50 top-of-the-line workstations, working simultaneously. By comparison, a person with a hand calculator, punching in one calculation per second, would need approximately 38,000 years to reach 1.2 trillion calculations.

Scalable supercomputers, sometimes called massively parallel computers, differ from the traditional supercomputers made famous by Cray Research. Machines such as the CRAY-1 and CRAY T90 employed a few large, custom-designed processors. Their printed circuit boards often measured as much as two feet wide and used as many as 54 layers. In contrast, the T3E employs commodity microprocessor chips made by Digital Equipment Corp. Entry-level, air-cooled versions of the T3E use as few as eight such microprocessors. A top-of-the-line, liquid-cooled CRAY T3E incorporates 2,048 processors.

Cray engineers say that the ability to scale up from eight to 2,048 processors is augmented by the development of a special scalable operating system and a custom-designed input/output system. Such new systems should help solve the programming challenges often associated with massively parallel computing.

Cray Research expects the T3E to be used for weather prediction, petroleum exploration, environmental studies, and atomic-energy research. Its most likely application in engineering is in the automotive field, for such applications as crash testing. Automakers have long used large supercomputers for crash analysis, enabling them to save tens of millions of dollars on prototype vehicles.

The Pittsburgh Supercomputing Center was the first user to receive a T3E in January, 1996. The center's new machine, a liquid-cooled model, is expected to be used for studies in quantum chemistry, material science, and protein sequence analysis.

--Charles J. Murray, Senior Regional Editor

Silicon Graphics boosts high-end power

Mountain View, CA--Silicon Graphics Inc. has created its most powerful graphics supercomputer ever: Onyx InfiniteReality, which offers up to 100 times faster visualization capabilties than SGI's former high-end computer, RealityEngine².

"Engineers can put things together digitally and fly through whole models and assemblies," says Daniel Vivoli at SGI. "Multiprocessing technology gives InfiniteReality supercomputing power and interactive visualization at the same time."

The newest Onyx processes more than 10 million polygons per second, provides 5 GFLOPS for image processing, downloads 200 MB/sec of image data into its visualization pipeline, and boasts a pixel fill rate of more than 800 million textured, anti-aliased pixels/sec. The system design features 230 million custom transistors for graphics performance. It can be configured with 1 to 24 MIPS R4400 processors and one to three InfiniteReality or Reality-Engine² graphics subsystems. Prices start at $125,000 for a uniprocessor system.

SGI officials say that technology appearing in the new supercomputer of today will eventually come down into the graphics desktop workstations of tomorrow.

Also this month, Silicon Graphics beefed up its Indigo² workstation family with Indigo² Solid IMPACT, boasting four times the overall graphics performance at a lower price than the model it replaces. The entry-level $22,000 model actually delivers more than two times the raw graphics performance of SGI's higher-end Extreme graphics, the company notes, based on the OpenGL DataExplorer benchmark. However, SGI officials say, Extreme still outperforms Solid IMPACT on certain other graphics tasks.

The entry-level Solid IM-PACT configuration comes with a 200-MHz MIPS R4400 processor, 2M secondary cache, 32M main memory, 1G disk, and 20-inch monitor. SGI says that the new MIPS R10000 processor will be available across the entire Indigo² line in the first half of this year.
For more information, see SGI's World Wide Web site at
http://www.sgi.com .

Infrared link speeds data at 4Mbps

Mahwah, NJ--Sharp Electronics Corp. is one of the first companies out of the gate with notebook PCs sporting infrared communications links that run at 4 Mbps.

The Infrared Data Association's (IrDA) previous standard supported 115-kbps bidirectional transfers. The new standard--which Sharp's PC-9000 series notebooks support--is 35 times faster. For example, the notebooks can send or receive text at approximately 160 pages per second, compared with 4 to 5 pages per second for 115-kbps devices. The Series 900 notebooks can also exchange computer graphics and still-picture video images, which comprise huge amounts of data.

At 4 Mbps, says Brian Greer, national marketing manager in Sharp's computer products division, the infrared link becomes a practical way of connecting notebook computers to corporate local-area networks when in the office. Previously, the notebook infrared links were mainly useful for printing short documents without hooking up printer cables and for exchanging limited amounts of data with desktop computers.

Additional PC-9000 series features include Pentium processors, removable quad-speed CD-ROM drives, memory expandable up to 40 Mbytes, Glide- Point pointing devices, 28.8-kbps voice/fax/data modems, lithiumion batteries, and MPEG video decoders for video compression. This combination of features plus the 4-Mbps infrared link virtually make the notebooks portable desktops.

Three configurations are available. Model 9010 has an 11.3-inch dual- scan color screen and 8 Mbytes of RAM. The 9040 comes with an active-matrix screen and a faster, 120-MHz Pentium processor. Finally, the 9070 has 16 Mbytes of memory and a 1-Gbyte hard drive instead of the 772-Mbyte version of the other two models. The notebooks are available this month.

Technology shortens journey to Darkstar

Palmdale, CA--With the assistance of new computer hardware and software tools, engineers at Lockheed Martin Skunk Works (LMSW) designed and built Darkstar--considered to be the world's most advanced unmanned aerial vehicle (UAV)--in just 17 months. The rapid development, said to be roughly 25% faster than normal for such a project, was accomplished through the use of CATIA (Dassault Systems, marketed by IBM, White Plains, NY) running on 27 IBM RS/6000 workstations and servers.

The UAV is the first-ever military aircraft to be completely electronically "built" in a CAD system without benefit of the many physical models normally used for structural or aerodynamic analysis. "We didn't have to do a mockup," says Bob Fischer, chief engineer on the program. "Everything, including the verification of fit, was done on the RS/6000." Workstation models covered IBM's product range including the 3CT, 3BT, 320, 360, 370, and a 560 server.

Fischer believes that CATIA's "pre-assembly" capability--pioneered on such aircraft as Boeing's 777--cut as much as six months from the design process. "When you can find out if you have interference before you have a (drawing) release, you save a lot of grief," he explains.

A network link allowed extensive data exchange between LMSW and Boeing, contractor for the detail design and manufacture of Darkstar's wing. While not unprecedented, such sharing was particularly important due to the unforgiving nature of the UAV's all-composite construction. Exceptional levels of fit had to be maintained for not only aerodynamic reasons, but also to minimize gaps that could compromise the aircraft's stealthiness.

"Unlike metal, you can't just hit (composite) with a hammer to make it fit," says Joe Kline, LMSW information resource manager. The wings, shipped thousands of miles from Boeing to LMSW, mated with the fuselage in less than three hours, including the attachment of plumbing and wiring. "I don't think you could do that without good computer tools," Kline says.

CATIA proved to be more powerful for 3-D modeling than LMSW's previous software. "It was especially good at surfacing the complex surfaces involved in a low observable radar signature," says Josh Lavinsky, technology manager for information services. Not limited to running just CATIA, engineers pushed the RS/6000 workstations with versions of NASTRAN; DOS emulation packages; SDRC's (Milford, OH) Master Series integrated design package; and Vericut, a tool-path verification package.

The first completely autonomous reconnaissance aircraft, Darkstar can stay on station for up to 8 hours, fly at 45,000 feet, maintain a headway of 250 kts, and range over a useful radius of 500 miles. Just 5 feet tall and 15 feet long with a 69-ft wingspan, it weighs a substantial 8,600 lbs loaded. Synthetic aperture radar and other electro-optic sensors gather reconnaissance information such as bomb assessment damage or enemy missile placements in near real time.

Most importantly--and unlike existing UAVs--Darkstar doesn't have to perform its duty from a safe distance. Says Fischer, "We can overfly targets--defended targets--and survive."

--Mark A. Gottschalk, Western Technical Editor