Focus on fuel cells: Ford's fuel cell fleet takes shape

Automotive Industries, Sept, 2004 by John McCormick

Traditionally, ultra-low volume vehicles costing hundreds of thousands of dollars are the preserve of Italian of German exotic sports car manufacturers. But a series of 30 cars being completed in a nondescript Detroit warehouse this month defies that notion.

To look at, the Ford Focus sedans being assembled by MSX International are far from exotic, but the cars' componentry and powertrains are highly unusual, hence their $300,000 to $400,000 estimated cost. This prototype program, dubbed C264 by Ford, aims to deliver small fleets of fuel cell powered Focus cars (FCVs) to city governments and universities in three major cities, Sacramento, Orlando and Detroit, this fall.

At the MSX facility in east Detroit, which previously assembled the electric Ranger for Ford, the Focus FCVs are coming together in a station build process, surrounded by a warehouse of specialty components. The process starts with a body delivered from Ford's Wayne assembly plant. Heavily modified, to accommodate the underbody mounted 85kW fuel cell stack and system module, the Focus body features high strength steel to meet crash requirements, as well as aluminum outer panels and a carbon fiber decklid.

The extensive use of lightweight components, which also includes titanium springs (a feature shared with Ferrari) and forged aluminum suspension arms, is all in the cause of offsetting the extra mass of the fuel cell powertrain. Even with the lighter parts, the 3,527 lb. Focus FCV still comes in 882 lb. heavier than a production Focus.

The FCV program, led by chief engineer Mark Mehall, worked closely with Wayne assembly to simplify the process wherever possible. "Wayne helped us to get all the new technology through their plant, using their framing fixtures," says Mehall. "For example, it is the first time they put stainless steel panels through the stamping plant. We used novel approaches to make aluminum parts off production tools, so it's been a joint effort with manufacturing and engineering to bring this project home."

The choice of the Focus for the FCV project was driven in part by the fact that the platform was being developed as a pure electric car. However as the electric vehicle market failed to materialize, it was found that the fuel cell components would package in the same area intended for the battery pack. "So it was a logical choice to take what we had been doing with batteries and replace them with the fuel cell," says Mehall. Positioning the $100,000 stack, supplied by Ballard power Systems, under the body also pays dividends in terms of protecting such an expensive component in case of an accident.

As it happens, the Focus FCV does use a battery, although a much smaller one than that in a pure electric vehicle. The car is designed as a hybrid and utilizes a Sanyo-supplied battery pack that provides extra boost when taking off from the rest of accelerating. The battery pack and associated regenerative braking system (supplied by Continental Teves) are derived from Ford's Hybrid Escape production sport utility vehicle. However, while the Escape is a full hybrid the Focus FCV is designed as a mild hybrid, meaning that the battery pack cannot drive the vehicle by itself.

On the MSX "assembly" line the Sanyo battery pack is installed behind the rear seat near to the end of the process. Prior to that, many of the 400 unique components (about one quarter of the total parts count of a Focus) are fitted, including the front and rear cradles, electric motor, suspension, cooling loops, electrical pumps and fans, radiators, DC/DC converters, controllers and wiring. Most of the critical plumbing and high voltage wiring is colored orange to warn rescue crews in case of an accident.

The trunk space is largely taken up with a Dynatech 5,000 psi tank, which holds 4 kg of compressed hydrogen. However this may be replaced later in a few of the fleet cars by a 10,000 psi tank. This will improve the vehicle's range from around 200 miles currently to 300 miles of more. The range will not double, explains Mehall, because the walls of the higher pressure tank are thicker and therefore it does not contain twice the gas volume.

Among the final assembly procedures for the MSX workforce, which numbers 30 in all, is the insertion of the Ballard 902 stack and system module unit. This large rectangular module is loaded from underneath the vehicle and its wiring and plumbing fixtures are connected to the car.

Although the stack itself is free of moving parts, an examination of the mechanicals of a near-complete Focus FCV reveals a very complex machine. And this complexity is part of the challenge facing not just Ford argues Mehall but all the auto makers engaged in fuel cell vehicle development.

"We are looking downstream," says Mehall. "We're going to get cost out by simplifying the system, by making it more robust and making it run in a stable way. These are all new technologies. We're trying to accomplish in three of four years what took 100 years to refine with today's vehicles.