【正文】 ave overe the technical barriers to attaining the high stack performance needed for fuel cell electric vehicle engines. Hydrogen, however, is not considered a technically and economically feasible fuel for private automobiles now nor in the foreseeable future. Automotive fuel cell engines must be able to use widely available, inexpensive liquid fuels such as gasoline or similar petroleum distillate fuels, or methanol if it can be supplied at petitive cost in the amounts needed. PEM fuel cells have shown some ability to use methanol directly, but breakthroughs in electrode performance and membrane resistance to methanol diffusion are needed before the direct methanol fuel cell can be considered a candidate for development of fuel cells for automobiles. Practical fuel cell electric engines for automobiles, therefore, must have fuel processors capable of converting gasoline or methanol into a hydrogenrich fuel gas that can be used by the PEM stacks to generate power.Methanol has been selected by the European and Japanese automotive fuel cell development programs because it is considered easier to process and expected to result in somewhat higher fuel efficiency as well as lower overall carbon dioxide production. The methanol industry appears confident that the required expansions of the methanol supply (from conversion of natural gas) and distribution infrastructures can be put in place at the rate and costs required by an expanding population of fuel cell electric vehicles. In the United States, gasoline is being stressed increasingly for automotive fuel cells because of the existing fuel infrastructure. It is not clear, however, whether today’s pump gasoline will be patible with PEM fuel cell systems for long periods, and the best petroleumderived fuel for automotive fuel cells may well be a simple distillate cut (without additives) from which sulfur has been largely removed at the refinery.Because all fuel processor types prise multiple process units and involve extensive thermal integration within the processor and with other parts of the fuel cell system, they pose difficult development problems. Several leading programs have succeeded in developing processors to the proofofprinciple (“breadboard”) stage but none of these meets all the criteria for automotive applications。 rapid cold start is a particularly difficult, as yet unmet , fuel processors and other essential balanceofplant ponents need to be integrated into plete fuel cell engines that have acceptable weight, volume and operating characteristics while realizing the nearzeroemissions and highefficiency potential of fuel cells.This integration, the central technical challenge in fuel cell engine system development, has been attained in a few development programs, but only on the breadboard level. DaimlerBenz has taken the key step of integrating a methanol fuel processor with a PEM stack and the necessary balance of plant equipment into an experimental fuel cell electric vehicle. While driveability has been established and the first measurements tend to confirm the expectation of extremely low emissions, this “NeCar 3” vehicle is a rolling test bed rather than a prototype.The other key challenge in automotive fuel cell development — achievement of manufactured costs parable to the very low costs of internal bustion engines — translates into stringent cost goals for every material, ponent, manufacturing step and assembly operation used to produce future fuel cell engines. Consideration of the materials and ponent costs suggests that there are no fundamental barriers to achieving PEM stack cost goals. The cost prospects of fuel processors and other key subsystems are less well understood at present, but it is clear that mass production on the level of at least 100,000 engines per year will be essential for all parts of the fuel cell engine system. The leading programs are being increasingly involved in developing the mass manufacturing methods that will be required to achieve cost goals.Major efforts are now underway in North America, Europe and Japan to develop all aspects of automotive PEM fuel cell technology. They are being undertaken by the organizations whose participation and leadership is essential if a mercially viable fuel cell electric engine is to emerge: leading automobile manufacturers with track records in advanced automotive technology, including the development of electric and hybrid vehicles. Equally important, the world’s leaders in PEM fuel cell technology are, or will soon be, participating in key alliances with these manufacturers. The integrated efforts are supported by wellfocused government Ramp。D programs of significant size (especially in the United States), and they draw on the advanced technology leadership of a growing number of organizations who look to PEM automotive fuel cells as a potentially large business opportunity for their specialized products and skills.In the Panel’s estimate, the Ramp。D investments made to date and the mitments for the next few years by major fuel cell developers and automobile manufacturers already are between $ and 2 billion, and additional resources — both, financial resources and technical capabilities — are likely to be mitted as programs move increasingly from Ramp。D into the more expensive phases of engine systems integration and evaluation/testing, engineering of all ponent, subsystem and system technologies for low cost mass production, and development of the required manufacturing processes.As discussed in some detail in this report, past efforts have resulted in remarkable advances in almost every aspect of automotive fuel cell technology, but major steps are still ahead even for the most advanced programs. At this time, the most pelling argument for the Panel’s cautious optimism about the prospects for ultimate success is that the promise of fuel cells as an environmentally superior and more efficient automobile engine is being purs