Multi-Fuel Fuel Processor and PEM Fuel Cell System for Vehicles 2007-01-0692
An ongoing program has made further technology advances in onboard fuel processors for use with PEM fuel cells. These systems are being explored as an option for reducing vehicle CO2 emissions and for other benefits such as fuel-flexibility that would allow vehicles to operate on a range of bio-fuels, conventional fuels, and synthetic fuels to support diversification and/or “greening” of the fuel supply.
As presented at the 2006 SAE World Congress1, Renault and Nuvera Fuel Cells previously developed fuel processor technology that achieved automotive size (80 liters) and power (1.4 g/s of hydrogen production) and reduced the startup time from more than 60 minutes to between 1.4 and 3.7 minutes to have CO <100 ppm. This paper presents an overview of the multi-fuel fuel cell power plant along with advances in the fuel processing system (FPS) technology and the testing results obtained since those reported in 2006.
The latest generation of this technology has made advances by improving the hydrogen efficiency to more than 80% over the entire operating range (33 to 215 kWth fuel input) while keeping CO below the 100 ppm target, lowering the pressure drop to improve system efficiency, and simplifying the balance of plant including eliminating the need for unreliable steam components. This fuel processor system also replaced laboratory air supply components with a low pressure drop automotive-style air supply system that successfully controlled the split of flow from the main compressor into three parallel branches for the ATR, Prox, and TGC.
In addition, an automotive fuel processor was tested with an automotive fuel cell stack and produced electricity from a broad range of fuels including ethanol, gasoline, and diesel. As an extreme demonstration of the fuel-flexibility, data is presented for a real-time switch from ethanol to diesel while the fuel cell continues to produce electric power. This demonstrates a switch from a bio-fuel to a difficult conventional fuel and also shows the use of a spark ignition fuel and a compression ignition fuel in the same hardware.