Paris debut for GM fuel-cell/by-wire concept

GM has more than 30 patents in progress covering business models, technologies, and manufacturing processes related to its Hy-wire fuel-cell by-wire concept.

General Motors Corp. has developed what it claims is the world's first driveable vehicle that combines a hydrogen fuel cell with by-wire technology. The appropriately named Hy-wire incorporates features envisioned in the AUTOnomy concept vehicle from the 2002 NAIAS Show held this past January in Detroit. The concept vehicle will be introduced to the public at the Paris Motor Show in late September.

Hy-wire was developed as a driveable concept vehicle in just eight months (from its introduction in Detroit). According to Larry Burns, GM's Vice President of research and development and planning, "With Hy-wire, we have taken the technology as it exists today and packaged it into an innovative driveable vehicle comparable in size and weight to today's luxury automobiles." It is the next step in the company's goal to have "compelling and affordable" fuel-cell vehicles on the road by the end of the decade.

GM designers in the U.S. developed the vehicle's chassis and body in close cooperation with Stile Bertone in Turin, where the body was built. Engineering and electrical-system integration were also carried out in the U.S. Engineers in Germany integrated the fuel-cell propulsion system originally designed for the HydroGen3 concept. The SKF Group developed the by-wire technology.

The Hy-wire's propulsion and control systems are contained within a skateboard-like chassis (similar to the AUTOnomy's) that maximizes interior space for five occupants and their gear. The combination of fuel-cell and by-wire technologies opens up new possibilities in chassis architectures and customized bodies, according to Chris Borroni-Bird, Director of GM's Design and Technology Fusion Group and Program Director of the Hy-wire concept. Added Ed Welburn, Executive Director of GM Design for Body-on-Frame Architectures, "The design is built around the fact that there is no engine compartment; the vehicle is very open from front to rear. This is intentional to highlight the openness in the interior and the range of possibilities." To show off the new architecture, the front and rear panels are transparent, and the seatbacks are open, so onlookers can see through the car from front to rear. There are no B-pillars.

Steering, braking, and other vehicle systems are controlled electronically rather than mechanically by an X-drive by-wire unit that is easily configured for left- or right-hand drive. The controller provides greater freedom for the driver, who has the option of braking and accelerating with either the right or left hand. Acceleration is made possible by twisting either the right or left handgrip, and braking is handled by squeezing an actuator on the handgrips. The handgrips glide up and down for steering. The X-drive also incorporates an electronic monitor for vital car functions and moves easily from left to right on a cross-car horizontal bar.

A docking port provides the electrical connection between the all-aluminum chassis and fiberglass body, which are linked mechanically by 10 body attachments. The fuel-cell stack, which produces 94 kW, is installed in the back of the chassis. Most of the chassis is 11 in (280 mm) thick, tapering to 7 in (180 mm) at its edges. Propulsion is provided by an electric motor positioned transversely between and driving the front wheels. Three cylindrical 5000-psi (34.5-MPa) Quantum hydrogen-storage tanks are located centrally in the chassis.

Though still fairly heavy at 1900 kg (4180 lb), most of the Hy-wire's technical elements are placed centrally and low in the chassis for a low center of gravity, giving the architecture high safety and driving-dynamics potential. GM says passive safety requirements will be fulfilled by adding impact-absorbing elements at a later stage of development.

- Kevin Jost

Dodge's racy Viper

DaimlerChrysler is going to build 30 to 50 3200-lb (1450-kg) 2003 Dodge Viper Competition Coupes per year.

With performance estimates of 0 to 60 mph (0 to 97 km/h) in 3.8 s, 0 to 100 mph (0 to 160 km/h) in 9.2 s, as well as 100 to 0 mph (160 to 0 km/h) braking in 260 ft (30 m), the new Dodge Viper Competition Coupe is a speed-and-stop demon.

"The Viper Competition Coupe is a nonstreet legal race car that we're building for the semi-pro racer who wants a turn-key car that's safe, reliable, and competitive," said Herb Helbig, Senior Manager of Vehicle Synthesis for DaimlerChrysler Corp.'s Performance Vehicle Operations.

Based on the 2003 model year Dodge Viper RT-10 convertible chassis, the Competition Coupe is the latest iteration in the Viper racing heritage. (The Dodge Viper GTS-R claimed five international GT championships, including the 1999 and 2000 American Le Mans Series GTS class title and the 1997-1999 FIA GT Championships.) The Viper Competition Coupe is eligible to compete in the Skip Thomas Viper Racing League, the Grand American Cup's Grand Sports Class (which includes the Chevrolet Corvette and Porsche 911), and SCCA Pro Racing Speedvision World Challenges.

The Competition Coupe's carbon-fiber body sports unique aerodynamic trimmings—rear wing, rear diffuser, and front splitter. "It gives the car substantially more downforce to allow it to corner and brake harder," said Eric Petersen, Lead Development Engineer on the Viper Competition Coupe.

The single-seat Competition Coupe's 8.3-L 10-cylinder engine produces an estimated 520 hp (388 kW) at 5600 rpm and 540 lb•ft (732 N•m) at 4600 rpm. "The engine has a higher performance camshaft and different engine calibration as well as a lower back-pressure exhaust than the 2003 Viper convertible," said Petersen.

The Viper Competition Coupe's interior features a Recaro seat, Team Tech restraint, and a Motec race dash and date-acquisition system.

The suspension package includes cast aluminum unequal-length upper and lower A-arm front and rear arms with spherical bearing frame attachments, high-rate anti-roll bar, and front and rear compression and rebound adjustable dampers.

The rear-wheel-drive car also is equipped with four-piston Brembo brake calipers, carbon-fiber front cooling ducts, Michelin Pilot racing slicks, Recaro Pro Racer competition seat, Team Tech six-point driver restraint system, driver-activated fire suppression system, custom-fitted side window netting, and a six-speed manual transmission with overdrive. Racers can track performance progress via a Motec race dash and data-acquisition system. "You can download information to a laptop. It allows the driver to compare laps and monitor the car and the driver's performance," said Petersen. An air jack system is available. "You plug in a supply of nitrogen—by a nozzle at the rear of the car—and it lifts the car up to change the tires," said Petersen.

The $100,000 car unfolded from a 15-month development program. "We're going to hand-build 30 to 50 cars per year," said Petersen.

- Kami Buchholz

Porsche gives Boxster more punch

The revised Porsche Boxster receives subtle aerodynamic changes to its front end and a redesigned rear spoiler configuration.

Of all the world's automotive manufacturers, Porsche is the master of model evolution. The latest 911 may, in pure technological terms, be light years away from the 1960s original, but it remains true to its fundamental mechanical principles, and the styling still retains its distinctive basic signature. Porsche is doing something of the same with its mid-engined Boxster—first seen six years ago—as it evolves the car. The latest changes include VarioCam technology (providing infinite adjustment of the camshaft up to 40°) to minimize losses in the cylinder charge cycle with the result that power output is increased but fuel consumption and emissions are reduced.

The power increase of 2.7-L and 3.2-L Boxster S engines is 8 kW (11 hp), giving 168 and 191 kW (225 and 256 hp), respectively. Fuel consumption is reduced by about 2% on both models. Intake camshaft timing is fully variable via a wing-cell adjuster fitted directly to the camshafts in the drive sprocket. Porsche claims to have been the first manufacturer to introduce the integrated design in the current 911 Carrera. Oil pressure is used to turn the position of the inner wing adjuster wheel versus the outer sprocket by up to 40° crankshaft angle. Porsche adds that the new VarioCam system makes the conventional three-stage chain drive between the crankshaft and the camshaft redundant, the intake and outlet camshafts being driven instead directly via a roller chain from the layshaft. The car uses Motronic ME 7.8 engine management. A "returnless" fuel system has been introduced, incorporating pump, filter, and pressure regulator in the tank.

VarioCam technology gives the Boxster added power and lower fuel consumption and emissions.

The Boxster's handling has been enhanced with newly designed lighter alloy wheels, which reduce unsprung weight. Boxster also uses a Media Oriented Systems Transport (MOST) databus. The Boxster's plastic rear windshield has been replaced by a (heated) glass type, and the car's roofline is improved. Opening and closing time for the roof is a very rapid 12 s. Styling changes include modifications to the car's front end to improve aerodynamics, both to enhance cooling airflow and provide greater downforce. The rear spoiler has been redesigned to take advantage of altered airflow over the rear of the car as a result of its redesigned roof profile.

- Stuart Birch