'All-new car' not so easily defined when 'building blocks' are adapted

  • 08-May-2009 02:45 EDT
hyundaicoupe2.jpg

The Genesis coupe (left) is built primarily on highly flexible assembly lines shared with the eight-passenger, diesel-powered i800 van.

"It's an all-new car" is a popular marketing claim, but what really does that mean? Government agencies typically seek to apply the "new" description liberally, to hasten mandated phase-in installation of new safety, emissions, and fuel-economy upgrades.

When cars are tied clearly to specific platforms, industry observers can see under the sheet metal to determine "newness." Over a period of years, a single platform can spawn everything from a mass-market sedan to a luxury model, minivan, car-like SUV, and crossover.

However, when vehicles are related by "architecture"—i.e., selected building blocks—there is more differentiation possible in derivative models, and it can be a game changer both for the manufacturer and government agencies. The European Union, for example, set a Jan. 1, 2011, date for "new type" vehicles to be equipped with air-conditioning systems that have a low-global-warming refrigerant. Exactly what constitutes a "new type" has emerged as a subject for debate between the regulators and some manufacturers.

The architectural approach combines highly flexible assembly lines, some carryover parts, some brand-new parts, modified "parts bin" components, and sophisticated tuning and calibrations. Creative engineering can employ a surprising amount of carryover componentry—invisible to customers, regulators, even knowledgeable observers—to form what generally will be perceived as "all-new" vs. "spin-off."

An interesting example is the 2010 Hyundai Genesis coupe, a rear-wheel-drive "driver's" car added to the line with the entry-luxury Genesis sedan, but a full price range below it.

If the coupe came down the same assembly lines as the Genesis sedan, that would be a tip-off. But until a future date, the coupe shares highly flexible assembly lines with the far taller, longer, wider, and heavier i800 eight-passenger diesel-powered multipurpose van at a plant in Ulsan, Korea.

The engine is a 2.0-L turbo four, a Hyundai first of sorts but a version of the "world engine" used on other Hyundai and Kia models—also by Chrysler and Mitsubishi. An optional 3.8-L V6 is a version of the V6 in the Genesis sedan, but it also is installed in many other Hyundai and Kia models. Further clouding the issue is that the coupe cowl does not have the same location as the sedan, which would have hinted at a sedan origin. The more forward location on the coupe permits a lower hood line, although it makes unlikely future use of the Genesis sedan's V8, a new engine that highlighted the sedan's "new" appellation.

The coupe's product planners had the assignment of developing a new look, new functionality, and enhanced performance throughout, at much lower cost than the sedan, without skimping on what the customer might see.

Frame rail side members are adopted straight from the sedan, and Hyundai Motor America President John Krafcik called them the "key building blocks ... the key determinants of the crash pulse." Their sedan-proven design provides a confidence for the other front-end systems that interact with them, he added.

Although the engine lineup is different, the coupe's front subframe is the one used for the 3.8-L V6 sedan, but with different locations for bolt holes and specific brackets for the 2.0-L turbo. The change in engine compartment dimensions vs. the sedan also requires specific intake and exhaust systems, which also give the coupe 3.8 V6 a different underhood look.

Front suspensions are different—two-link MacPherson strut for the coupe vs. higher-cost five-link in the sedan. The two models share a five-link rear suspension and rear axle, with the coupe suspension modified to accept the axle.

In addition to the front side members, much of the center and rear floorpan sections are closely related designs, so it is not surprising that the coupe body-in-white's dynamic rigidity numbers are close to those of the highly rated sedan—51.6 Hz vs. 52.1 Hz for the sedan in bending, 32 Hz vs. 40.9 Hz in torsion. Also adopted with modest modifications were fuel tank, propeller shaft, brakes, steering (including the column), and automatic transmission shift mechanism.

The body subassembly setup (with the initial welds) is on a specific coupe line, but from there it goes to highly flexible lines for body respot (primary spot welding), paint, and final assembly, which are shared with the large i800 van. When another rear-drive sedan (Equus) is introduced, the two sedans and coupe probably will come down the same lines.

Electronic architecture is building block from sedan for the coupe. The basic systems for safety and powertrain are on high-speed CAN (500 kbit/s) while other electronics are on medium-speed CAN (100 kbit/s). Both models have a power distribution module in the cabin, but the coupe's lower electronic content means it doesn't need the front-end module used by the sedan. Both cars employ the same strategies for data bursts and module wake-ups.

The sedan also has a high-end infotainment system, which requires a specific fiber-optic network (MOST) not needed on the coupe.

If "new" is in the eye of the beholder, Genesis coupe fits the description. But if it comes down to an engineering argument with regulators, the answer well could be, “not quite.”

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