Mobile applications

Three types of lines are used in fluid power systems pipe (rigid), tubing (semi-rigid), and hoses (flexible). A number of factors are considered when the type of line is selected for a particular application. These factors include the type of fluid, the required system pressure, and the location of the system. For example, heavy pipe might be used for a large, stationary system, but comparatively lightweight tubing must be used in mobile applications. Flexible hose is required in installations where units must be free to move relative to each other. 

The presence of impurities is an important issue in mobile applications where the hydrogen at least initially will be supplied by the decomposition of hydrocarbons or methanol in on-board reformer systems as long as no appropriate hydrogen storage media are available. In such systems CO is an unavoidable by-product, and since CO binds more strongly to Pt than hydrogen, the low operating temperature... 

While the PEM fuel cells appear to be suitable for mobile applications, SOFC technology appears more applicable for stationary applications. The high operating temperature gives it flexibility towards the type of fuel used, which enables, for example, the use of methane. The heat thus generated can be used to produce additional electricity. Consequently, the efficiency of the SOFC is -60 %, compared with 45 % for PEMFC under optimal conditions. 

In the United States, the Department of Defense (DOD) and the Department of Energy (DOE) promoted in 1992 the Defense Advanced Research Project Agency (DARPA) program to develop a DMFC for portable and mobile applications. Several institutions are involved (IFC, JPL, LANE, Giner, Inc.) and small stacks (up to 10 elementary cells) were built by IFC and JPL. The performances are quite encouraging, with power densities of 250 mW/cm at 0.5 V. More details are given in Section V.2. 

In battery applications, new hthium ion batteries called lithium ion polymer batteries (or more simply but misleadingly, lithium polymer batteries) work with a full matrix of ionically conducting polymer, this polymer being present inside the porous electrodes and as a separator between the electrodes. They are offered in attractive flat shapes for mobile applications (mobile phones, notebooks). 

Various other classes of catalysts have been investigated for NH3-SCR, in particular, metal-containing clays and layered materials [43 15] supported on active carbon [46] and micro- and meso-porous materials [31b,47,48], the latter also especially investigated for HC-SCR [25,3lb,48-53], However, while for NH3-SCR, either for stationary or mobile applications, the performances under practical conditions of alternative catalysts to V-W-oxides supported on titania do not justify their commercial use if not for special cases, the identification of a suitable catalyst, or combination of catalysts, for HC-SCR is still a matter of question. In general terms, supported noble metals are preferable for their low-temperature activity, centred typically 200°C. As commented before, low-temperature activity is a critical issue. However, supported noble metals have a quite limited temperature window of operation. 

Burch, R. (2004) Knowledge and know-how in emission control for mobile applications ,... 

Due to the trade-off between low-temperature activity on the one hand and selectivity as well as stability on the other hand, a compromise has to be found for the vanadia concentration. Most extruded commercial SCR catalysts for mobile applications contain between 1.7 and 1.9% V205, but there is a trend to further reduce the vanadia concentration in order to suppress the N20 formation at higher temperatures and to increase the temperature stability of the catalyst. 

Schlapbach, L. and A. Zuttel, Hydrogen-storage materials for mobile applications. Nature, 414, 353-358,2001. 

Metal Hydride Requirements for Hydrogen Storage for Mobile Applications... 

Lang M, Szabo P, Ilhan Z, Cinque S, Franco T, and Schiller G. Development of solid oxide fuel cells and short stacks for mobile applications. J. Fuel Cell Sci. Technol. 2007 4 384-391. 

Schiller G, Henne R, Lang M, and Muller M. Development of solid oxide fuel cells (SOFC) for stationary and mobile applications by applying plasma deposition processes. Mat. Sci. Forum 2003 3 2539-2544. 

Farrauto el al.549 report that It is clear that an ideal catalyst for WGS needs to be developed, especially for mobile applications. Indeed, Cu-Zn still dictates the performance standard for fuel cell reformers, even though its pyrophoricity is prohibitive for its use. Higher activity is always desired, as well as the tolerance to flooding and sulfur. In that respect, a precious metal catalyst has obvious advantages but often cannot compete with the price of a base metal system. A three- to four-fold increase in activity would be needed to achieve that advantage. ... 

Achieving a high gravimetric storage capacity is one of the greatest challenges in automotive and mobile applications. However, for stationary applications, the... 

An analysis of the individual PEM components offers evidence of almost unbroken R D see Fig. 13.10 (Jochem et al., 2007). The overall importance of the membrane is striking. Furthermore, the numbers of annual applications for bipolar plates (BPP) and the gas-diffusion layer (GDL) decrease after 2002, while the increase in membrane applications flattens out. This correlates with the equally lower number of fuel cell patents in the field of mobile applications. 

Wurster, R. (1999). PEM fuel cells in stationary and mobile applications - Pathways to Commercialization. Sixth International Technical Congress - BIEL 99. Biel Bienal de la Industria Electrica y Luminotecnica. CADIEM Camara Argentina de Industrias Electromecanicas. 

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