No respect: EV1's aluminum body shouldn't stand in Prowler's shadow

Chrysler Corp.'s Plymouth Prowler is so over-exposed in Detroit, even street people can tell you about its innovative aluminum body between sips of cheap wine. "And at only $35,000, it will be very affordable," they say. Then they ask for spare change.

But the equally ingenious aluminum structure of General Motors Corp.'s EV1 electric car, which hits the marketplace this fall -- about six months before Prowler -- gets no such respect or notoriety, even though it will officially be the first production car in North America to feature an all-aluminum structure.

Perhaps the EV1's unique propulsion technology overshadows all other aspects of the car. Then again, maybe it's because few automotive journalists think electric vehicles are sexy enough to lovingly write about every last nut and bolt.

But my guess is that Alcoa's role in co-developing the Prowler body is a lot better known than competitor Alcan Aluminum Ltd.'s contribution to the EV1 because Chrysler -- in characteristic fashion -- has aggressively promoted the development work of its supplier "partners." GM hasn't. Just promoting the idea of a sellable electric car probably is an overwhelming task in itself.

Whatever the reasons, Chrysler's Prowler -- despite the fact that 30% of its exterior panels are made of plastic sheet molding composite (SMC) -- has become a poster child for aluminum and imaginative, lightweight vehicle bodies. Meanwhile the EV1's aluminum body structure has remained anonymous, a stranger encased in the electric car's plastic body panels.

This lack of visibility is unfortunate because Alcan -- like Alcoa -- has spent well over $100 million for auto-related research and development in recent years. But more importantly, the unique aluminum technology in the EV1 arguably has more significance to the real world of high production than the Prowler.

Critics may argue that EV1 sales volume will be so low (GM won't offer projections) that its construction doesn't warrant serious scrutiny from the high-volume sector. But Alcan officials say the EV1 actually employs an Aluminum Vehicle Technology (AVT) system that has been engineered for high-volume use, with more than 15 years of continuous development. It's already in use successfully on low-volume supercars such as the Jaguar XJ220. The EV1's aluminum body-in-white may have started years ago as a fancy, hand-built experiment, but it's now capable of greater things.

Unlike Prowler, which uses lots of extrusions connected with cast aluminum nodes, has a full perimeter frame, and resembles race-car construction in many ways, the EV1 features a more conventional sheet-based body frame that integrates the functions of the car body and chassis in the same way as a conventional unibody. The structure is made from pre-treated, lubricated aluminum sheet, stamped into structural panels using traditional production techniques, then assembled with a specially formulated adhesive, spot welds and/or mechanical fasteners.

All mechanical components of the vehicle and the plastic exterior panels are attached to this weld-bonded aluminum body structure. Extrusions, castings and other sheet fabrications or "foldings" are integrated into the design to simplify assembly. Half of the parts are stamped, which keeps tooling costs low, Alcan says.

All-in-all it's not exotic-sounding stuff. Compatibility with today's high-volume manufacturing methods -- and existing metal stamping and assembly techniques -- is a key part of the AVT design, emphasizes Donald Macmillan, vice president and general manager-Automotive for Alcan Rolled Products Co.

Officials at Alcan say the AVT allows for use of virtually all forms of aluminum, which enables the material to be used economically for both low- and medium-volume vehicle production. Yet because it is compatible with high-volume production processes, it also is feasible for large-scale production.

And despite the emphasis on cost, the EV1's body is as rigid and durable as some of the world's best, Mr. Macmillan says.

In other words, the EV1 may not attract potential trophy wives like the Prowler, but it's every bit its equal in the materials race.