Crain News Service
DETROIT - Chrysler Corp. shocked the automotive world in September 1997 when it announced plans to test the feasibility of making a car body encased in plastic.
Now, DaimlerChrysler Corp. wants to shock the auto world again. This time, the company is out to prove that injection-molded plastic bodies are possible for larger, road-toughened vehicles, where a sturdy frame is a must.
The automaker unleashed a prototype sport-utility called the Jeep Commander at the North American International Auto Show this month in Detroit. The concept vehicle features a fiberglass body.
But if the sport-utility goes into production, polyethylene terephthalate most likely would be substituted for the composite material, said Larry Oswald, executive engineer for body panels at DaimlerChrysler's Liberty & Technical Affairs development center in Madison Heights, Mich.
USES OF PLASTIC
Fiberglass would not sustain the same side impact as polyethylene terephthalate, Oswald said. But it offered a quick means to build a prototype vehicle in time for the auto show, he said.
Either way, DaimlerChrysler is showcasing the Commander partly to offset myths about plastic's limitations, Oswald said.
'Some suppliers still think that plastics can't be used for (structural) body panels,' he said. 'We're working on changing that thinking. Now we want to show they can be used for larger vehicles, not just in small cars.'
The Commander is based partly on the 1999 Jeep Grand Cherokee, but it is 80 inches wide, more than seven inches wider than the Grand Cherokee.
But as large as the vehicle is, it also is fuel-efficient. DaimlerChrysler Corp., showcasing a line of advanced powertrains at the news conference, has added a gasoline-powered fuel cell that allows the four-wheel-drive vehicle to run on electricity.
The use of plastics was a way to keep down the vehicle's weight and counterbalance the heavier powertrain, said Bernard Robertson, DaimlerChrysler senior vice president of engineering technologies. Despite the powertrain's weighty 2,100 pounds, the entire vehicle weighs only 5,000 pounds, about that of a typical sport-utility.
The use of plastics would save as much as 50 percent of the vehicle's body weight compared with steel, according to DaimlerChrysler research.
'We'd like to build an SUV with this type of powertrain,' Robertson said. 'The use of injection-molded plastic would help offset the extra weight from the fuel cell.'
The Commander also uses plastic in a variety of other ways, said DaimlerChrysler exterior product designer Steve Won
At high speeds, a rear spoiler lowers from the Commander's roof to aid performance. A roof rack, set flush to the roof, deploys upward when luggage is needed. The plastic side mirror has its own wiper.
The surface also features molded-in color capable of providing a shiny, metallic-silver finish to the vehicle, Oswald said. Current technology allows for surface finishes that approach those gained by painting, he added.