Cleaner than air – Sakuji Arai, Honda’s natural-gas Civic – 1997 Discover Awards: Automotive & Transportation – Brief Article
EIGHTY MILLION PEOPLE IN THE UNITED States are breathing unacceptably high levels of air pollution, according to the U.S. Environmental Protection Agency, and automobile emissions are a major culprit. Engineers at Honda took this gloomy statistic as a challenge. “Building on our latest technologies,” says Sakuji Arai, leader of Honda’s natural-gas group, “I guided my engineering team to design the cleanest internal combustion engine ever made.” They were understandably pleased with themselves when they unveiled their prototype, installed in a Civic, last November. There was only one problem: its exhaust was cleaner than the air in some cities. At official inspection stations, tailpipe emissions would simply not register.
Arai’s team eventually managed to detect their engine’s “nearly unmeasurable” emissions. It suppressed hydrocarbons, nitrous oxides, and carbon monoxide at least 60 times better than the 1997 federal limits for new cars. It even bested California’s much stricter targets for ultralow emission vehicles (ULEV), the world’s toughest goals, by a factor of ten. In fact, Honda’s natural-gas Civic accomplished all this without sacrificing the benefits of good old internal combustion, such as more horsepower and longer driving range, or the lower cost of mass production.
The choice of fuel–natural gas–had much to do with Honda’s record-shattering success. Natural gas contains methane and burns more efficiently than gasoline. And since methane contains less carbon than gasoline, it produces less carbon dioxide, a greenhouse gas. But Honda’s persistence was also crucial to the project. The company had already managed to meet the strict ULEV standards with an experimental gasoline engine, so it had no practical need to make further improvements. Honda engineers nevertheless wanted to see how close they could get to a true zero-emissions car, and they decided to modify the gasoline engine to accept natural gas. This involved designing new software to manage combustion variables such as fuel-to-air ratio, new fuel injectors and engine parts redesigned for higher compression, two catalytic converters, a completely sealed fuel system throughout the car to eliminate evaporative pollution, and a fuel tank made of fiber composites that is strong enough to hold sufficient compressed gas for 220 miles of “real world” driving.
The car is scheduled to roll off the same Ohio assembly line as the gasolineburning Civic this fall and will cost $4,500 more. The catch is that right now only fleet-operating companies that have natural-gas depots will be able to fuel it. That’s why Honda’s engineers pushed not just to beat ULEV standards but to demolish them: they wanted stunning proof that this alternative fuel can rout urban smog–and that more drivers should be able to get it.
FINALISTS
REINVENTING THE CAR
General Motors’ EV1 INNOVATOR: KENNETH R. BAKER
Here’s the problem: Take a standard automobile; reduce the amount of energy it can carry on board to the equivalent of half a gallon of gasoline, and add almost a ton of deadweight in the form of 26 lead-acid batteries; don’t sacrifice air conditioning, power windows, CD player, rear-window defogger, or any other amenities, and make it handle tight to the road like a sports coupe.
Like a trick question on an engineering exam, the solution, it turns out, is to reject the whole premise. You can’t just start with a standard automobile, remove its guts, and plug in electric parts. “We needed to create a new automobile,” says Kenneth Baker, General Motors’ vice president for research and development. But how? One clue came from GM surveys on driving habits, which suggested that a car with a limited range would serve 90 percent of driving needs. A small two-seater with a range of only 70 to 90 miles between rechargings could be trimmed by hundreds of pounds and still serve adequately as a second car for everyday commuting, shopping, and driving the kids to school.
The rest of the solution came down to a fanatic quest for efficiency. Paul MacReady, founder of the engineering firm AeroVironment in Monrovia, California, worked out the basic design in a “concept car” called the Impact, which is lightweight, has a highly aerodynamic shape, low rolling resistance, and regenerative braking. The Advanced Technology Vehicle group, led by engineering director Jim Ellis, then whipped out a proof-of-concept car in just 99 days. Teams assigned to each subsystem, such as the 290-pound aluminum frame, tracked every part’s weight to a thousandth of a gram, through five design generations. “The final product,” Ellis says, “accelerates zero to 60 in less than nine seconds.” That matches the performance of a BMW 3181, but with zero emissions.
Unfortunately, the conventional leadacid batteries that give the EV1 its zip don’t put out much juice in cold weather. For this reason, the EV1, which was first made available in Arizona and California last December, won’t arrive in the smoggy Northeast until somebody invents a better all-weather battery.
THE TURNING OF THE SCREW
Lawrence Livermore National Laboratory’s Spiral al Track Autonomous Robot (Star) INNOVATORS: WILLARD H. WATTENBURG AND MARK L. PEREZ
For all obstacles, hazards, and sheer ugly terrain that would thwart the advance of robotkind, Bill Wattenburg came up with a simple, elegant rebuttal screw’em. Neither sand nor mud, talus nor scree, not swamps, ponds, fallen logs, or even land mines or sniper fire will stop the robot Wattenburg envisioned. It rolls on a pair of giant screws. When they rotate in opposite directions, the robot rumbles forward. When they rotate in the same direction, it scuttles sideways. And when one screw turns while the other holds still, the screwbot deftly pirouettes. In water the hollow screws float and push like propellers.
Wattenburg’s simple idea tool robotic engineers at Lawrence Livermore by storm. “He is, a brainstorm generator,” says Erna Grasz, first leader of the Spiral Track Autonomous Robot project. Wattenburg–an inventive physicist, engineer, and host of a popular Bay Area talk-radio show–suggest ideas, Grasz says, “and we try the really cool ones.” He suggested, for instance, dragging chainlike nets by helicopter over open ground to detonate land mines safely, a scheme tested successfully during the Gulf War. This led him to think about rougher terrain–in Bosnia, say. Wattenburg decided that job would require a cheap but sturdy robot. Later, while watching an Archimedes’ screw lifting sand at a construction site, the eureka moment struck: one of those could move on the ground. “I looked,” he says, “and realized it would give us a mobile vehicle.”
Last October, Grasz’s team finished building a ground-hugging prototype tethered to a power supply. Wattenburg loved it: “This won’t tip over, like that robot in the volcano.” In fact, it even climbed stairs. Mark Perez, the current project leader, then designed an autonomous model that can also run by remote control. One version carries radar for detecting land mines. Various instruments might be mounted on it, Perez suggests, such as a video camera or stun gun to aid police work. The robot could even help with search and rescue missions after disasters, or explore the surfaces of other planets. A disadvantage, Perez found, is the high friction between the screw wheels and the ground, which keeps the machine to a one-and-a-half-mile-per-hour speed limit while moving forward or backward. On the plus side, the robot can travel sideways at a cool 20 miles per hour. It’s also robust, relentless, and relatively cheap–about $15,000 for the mine finder version. And a miniature screwbot made of colorful plastic parts would make a terrific child’s toy.
TURN AND PIVOT ON THREE
Oak Ridge National Laboratory’s Omnidirectional Platform INNOVATOR: STEPHEN KILLOUGH
Anyone who struggles to master parallel parking knows a plague as old as the oxcart: our glorious wheeled vehicles are hellish to maneuver in tight spaces. This mechanical glitch costs us dearly. Watch a forklift backing and forthing in a warehouse, or a wheelchair zigzagging through a twisted corridor and you’ll see magnificent examples of wasted motion. When Stephen Killough, a robotics engineer at Oak Ridge National Laboratory, saw the ancient curse in wheeled robots too, he came up with a solution that is technically sweet, mathematically elegant, and visually discombobulating.
His reasoning started with a simple question: Why couldn’t a car simply pivot like an office chair on casters and slide sideways into a parking spot? Because, he knew, you’d need a minimum of three casterlike wheels on the floor, and each would require two motors: one to drive its rotation and another to make it pivot. Six motors would be too unwieldy, complex, and expensive. According to engineering principles, Killough realized, you should be able to manage with only three independent motors, but nobody had been able to figure out how. Killough looked at the ideas other inventors had tried, including little rollers embedded around the rim of a bigger wheel, allowing it to roll sideways, but they were all flawed in some critical way. While playing around with such embedded rotations, however, he discovered an ideal arrangement.
Picture a round platform with three motors underneath, each governing the motion of two wheels that look like miniature balloon tires. The w heels in each pair are mounted in a cage at right angles to each other; the motor can rotate the cage so that one wheel or the other is touching the ground at any one time. By configuring the three pairs of wheels to allow the same type of motion found in three pivoting casters, and by changing the relative speeds of the motors, Killough can make his robotic platform rotate, follow a straight or curved path, and even rotate while moving forward.
After Killough nailed the mechanical design, Francois Pin helped him control the complicated choreography of the wheels with a computer. There is nothing intuitively obvious about the arrangement they must assume. “It’s almost like you have to trust the mathematics that says it should work,” says Killough. “It’s bizarre to watch. It flabbergasts everybody. It’s like a taffypuller machine.” In 1994 Killough and Pin readied their first public demonstration: they strapped a pen to their robot and wrote cursive letters on the floor. This fluent mobility led to a partnership in January 1996 with Cybertrax Innovative Technologies, a start-up company in Tampa developing a new motorized wheelchair. The U.S. Air Force will also try out the platform to load bombs onto fighter jets. But a forklift manufacturer that sent people to look at it isn’t convinced. “Customer acceptance,” Killough reckons, “is going to make or break this product.”
GARGANTUAN GIRDLES
XXsys Technologies’ Robo-Wrapper II INNOVATOR: LARRY CERCONE
A few years ago Gloria Ma, cofounder and chief executive of XXsys Technologies, a San Diego-based research and development firm, was looking for new ways to exploit materials such as the high-strength carbon composites used in lightweight rocket casings. She took notice when she learned that thousands of concrete columns under California highways were about to fall short of new earthquake standards because they needed more “hoop steel” reinforcement–that is, steel jackets bolted or welded around the columns. Carbon fibers woven and wrapped like Ace bandages around the columns would do the trick just as well, she thought. After all, pound for pound, carbon fibers are several times stronger than steel. Unfortunately, they are also 20 times more expensive than steel. So she asked Larry Cercone, who designed fiber-winding machines for aerospace jobs, if he could adapt his techniques to outdoor highway construction sites.
“Hell, yes,” Cercone replied. Automation, he realized, would be crucial to bringing down the cost of using fiber. It would also provide the fiber technology with a practical advantage over steel: whereas steel casings must be custommanufactured off-site and require heavy equipment to install, a fiber-winding robot could, in theory, wrap any size column on the spot.
Cercone’s prototype, called Robo-Wrapper I, was introduced in 1995, and it indeed spiraled up columns like a mad tailor, weaving 100 linear feet a minute. But that wasn’t fast enough. In September 1996, Cercone unveiled Robo-Wrapper II, which achieves 400 feet a minute by guiding 12 spools of fiber around the column like a bevy of spiders. Its operating crew of three can retrofit columns five to ten times faster than their rivals in steel, without using cranes or other heavy equipment. A doughnut-shaped oven wraps around the column and cures the composite in two hours. The result: a seamless, noncorroding jacket as thin as two hundredths of an inch that doubles or triples the seismic displacement each concrete column can handle.
Surprisingly, a low-tech problem all too familiar to the everyday handyman nearly stymied the project. “You have to get within an inch of the top and bottom of the column,” Cercone says. “Designing a machine capable of placing fibers that close, without running into things–that was the major challenge.”
Cercone has since built Robo Junior for tighter corners, such as those found in parking garages. He is also designing an underwater model for docks and other submerged structures. Although Robo-Wrapper II has won several competitive bids in California, Ma has set her sights on the one-third of all U.S. bridges that have been deemed structurally deficient–a $78 billion repair headache. A rust-weakened 1960s viaduct on Interstate 80 in Utah, one of Robo’s latest projects, turned out to be the kind of structure, Ma says, “that we could not only make as good as new but could actually make stronger than new.”
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