Full speed ahead for Ford

Associate Editor

Things are starting to heat up at Ford's Special Vehicle Team (SVT) headquarters: This year marks its official 10-year anniversary. But, according to John Coletti, director of SVT programs, "We're just picking up speed." Tucked away in a quiet corner in Dearborn, Mich., SVT works out of an unassuming, rather generic building. But lift the garage doors and there's eye candy as far as a gearhead can see.

Engineers at SVT gave Machine Design a look at vehicles such as the predecessor to the current Ford GT, a supercharged Ford Ranger (no plans for production), a Focus with a hefty 2.5-liter V6 stuffed in the engine bay, and a 2004 Mustang Cobra with its mysterious mystichrome paint scheme. Up on a lift hovered a preproduction Ford GT. However, any new information on the GT was off limits as engineers had the current version sequestered in another garage while they worked out final details.

What color is it?

Only 1,000 SVT Mustang Cobras will get a mystichrome paint job for 2004. The appearance package includes color-shifting exterior paint that changes with viewing angle from green to blue to purple and finally to black. On its 1996 Cobra, Ford used a less vibrant color-shifting paint that changed from black to purple to a reddish brown. The new paint, from DuPont, uses ChromaFlair light-interference pigments from Flex Products Inc. The pigment is opaque, flat, and highly specular. ChromaFlair pigment consists of five ultrathin, multilayer interference films that form micron-sized flakes. The flakes act like prisms, splitting white light into colors. Controlling the thickness of the multiple layers in the pigment's flake structure produces different colors.

To maintain tight color tolerance, the application process must control layer thickness to within a few atoms. This color-generation technology, called Color-By-Physics, consists of eight ChromaFlair pigments that are produced using the same materials. The pigments are stirred into the paint like any additive so they need no special handling or application. The pigment comes in a wetted form. Ten percent of the gross weight is Dowanol PNP, propylene glycol N-propyl ether. It is added to the pigment to minimize airborne particles. The Cobra's new paint also includes aluminum flakes for a metallic sparkle. To complete the look, mystichrome shows up on the seat trim.

Ford GT gets final touches

While Ford prepared three production versions of the GT for the company's centennial celebration, regular production begins in the spring of 2004 as a 2005 model. Price has not yet been confirmed, although it is rumored to be in the $100,000 to $150,000 range. (The price tag hasn't stopped some 5,000 potential owners from getting on a waiting list for the car.) The GT became part of the Living Legends lineup in 2002 and is now part of Ford's Performance Group. This Group consists of SVT, Ford Racing Technology, and the Vehicle Personalization organization.

To create a GT super sports car, Ford engineers developed an all-aluminum space frame consisting of 35 extrusions, seven complex castings, two semisolid-formed castings, and various stamped aluminum panels. A large center tunnel houses a midmounted fuel tank and cutout roof sections for cantilevered doors. "Using CAD/CAM and finite-element analysis, we were able to design and test several iterations of the fuel tunnel and roof structure," says Huibert Mees, chassis supervisor. "That let us significantly stiffen the overall structure," he adds. Another element of chassis rigidity is the application of friction-stir welding used to construct the multipiece aluminum tunnel that houses the fuel tank. A tool rotating at 10,000 rpm applies pressure to a seam and blends the metal there, forming a smooth, consistent seam. When compared to automated MIG welding, friction-stir improves the dimensional accuracy of the assembly, producing a 30% increase in joint strength. Because the seam is continuous, it effectively isolates the fuel tank from the passenger compartment. (For a detailed look at friction-stir welding, see Machine Design's "Causing a stir in welding" article, March 21, 2002).

The center position of the fuel tank helps reduce risks, especially in collisions. Its location also helps keep overall weight distribution and center of gravity consistent at differing fuel levels. The mechanical components -- including fuel pumps, level sensors, and vapor-control valves -- first mount on a steel rail. The single-piece tank then gets blow-molded around the rail to maximize fuel volume and reduce the number of connections to the fuel system. A capless fuel filler neck under an aluminum cover automatically opens when a fuel nozzle inserts, and seals the system when the nozzle is removed.

A "plus-nut" method joins body panels to the frame. The fasteners are aluminum nut inserts, with additional machining stock on the mating surface. When machining the suspension and engine mounts, CNC milling accurately trims each aluminum plus-nut for precise body positioning to eliminate the need for shimming the body. The result is lower assembly costs and better panel fit.

Aluminum body panels are manufactured using superplastic forming. This works by heating an aluminum panel to temperatures near 950°F, then using high-pressure air to plastically form the aluminum panel over a single-sided die. The resulting body panels can have complex shapes not possible with conventional stamping. The technique also cuts tooling costs because it requires only a single-sided die.

As an example, superplastic forming made it possible for the exterior of the rear clamshell engine cover to be one piece. The engine cover also features an aluminum shell hemmed to a carbon-fiber inner panel. The carbon-fiber piece is lightweight and rigid, helping stabilize the clamshell.

For aerodynamic balance, heat extractors in the front cowl were modified to pull heat from front-mounted radiators. Side intakes under the B-pillar are slightly enlarged to drive more cool air into the engine bay and transmission cooler. An additional set of vents on either side of the rear glass help diffuse heat from the engine compartment.

To keep the GT firmly planted on the road, engineers added a front splitter to its underside. This creates a high-pressure area for front downforce and limits the volume of air traveling under the vehicle. Side splitters were added to keep air from sliding under rocker panels. Also, venturi tunnels accelerate exiting air, creating a vacuum that sucks the car to the pavement.

Couple all this technology with a supercharged, 500-hp V8; a double-wishbone suspension with aluminum control arms, coil-over monotube shocks, and stabilizer bars front and rear; Brembo brakes; and fat 18 and 19-in. Goodyear tires. The result is a road-ready sports car that looks like it belongs on the racetrack.

Racing towards clean vehicles

On a completely different front, Ford's Research and Advance Engineering group is making leaps and bounds with its H²RV concept car. We were fortunate enough to take a spin in this eco-friendly vehicle. The 2.3-liter ICE is fueled by hydrogen, boosted by a supercharger (however, the engine is still a bit doggy), and a patented modular-hybrid transmission system. The hydrogen-fueled ICE is rated 110 hp at 4,500 rpm. An extra 33 hp kicks in when the electric motor assists for a total of 143 horses. As with most hybrids, the ICE shuts off after the car brakes to a stop. The resulting total silence gives an odd feeling. The car quickly starts up again when you press the accelerator.

Ford engineers call this the start/stop function. However, if the air conditioning is on, it also shuts off with the ICE. Making a change in the software can eliminate the start/stop function to keep the AC and ICE running continuously. For example, programming the controller to recognize that the compressor is working will keep the stop/start function from kicking in.

The electric motor in the transmission and embedded software stop the ICE as well as start it up again. The modular-hybrid transmission system consists of a single 300-V electric motor, an upgraded automatic transmission, and modified hydraulics. The H²RV also features a 288-V, 3.6 A-hr lithium-ion battery; a 288-V/14-V dc-to-dc converter; electric power-assisted steering; and integrated hydrogen and high-voltage safety systems. The 5,000-psi tank holds approximately 2.8 kg of hydrogen for a range of 125 miles.

The H²RV is considered a transition vehicle between conventional gasoline engines and fuel-cell vehicles. Its future depends on establishing a nationwide hydrogen-fueling infrastructure as well as laws and regulations.

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