Methanol fuel storage

Engines are also designed to use either gasoline or methanol and any mixture thereof (132—136). Such a system utilizes the same fuel storage system, and is called a flexible fueled vehicle (EEV). The closed loop oxygen sensor and TWC catalyst system is perfect for the flexible fueled vehicle. Optimal emissions control requires a fuel sensor to detect the ratio of each fuel being metered at any time and to correct total fuel flow. 

Plans are to offer a commercial vehicle by 2004. A hydrogen-fueled (metal hydride for hydrogen storage), fuel cell attery hybrid passenger car was built by Toyota in 1996, followed in 1997 by a methanol-fueled car built on the same (RAV4) platform (28). 

The storage, transportation, and handling of H2 are difficult. It has been reported that between H2 production and H2 application, a 15% loss due to leakage is unavoidable. Liquid methanol has advantages over H2 in this respect, and direct methanol fuel cells are presently believed to be the ideal energy converting alternatives to hydrogen PEMFCs. 

The demand for transportation energy is assumed to be covered by equal amounts delivered to electric vehicles and to fuel cell-based vehicles. For the former, a 50% storage cycle loss associated with the entire battery cycle operation is assumed, and for the fuel cell-based vehicles, operation is assumed to be based upon either hydrogen or a more storable derivative (e.g., methanol). Fuel cells are considered to have a 50% conversion efficiency. In both... 

The fuel cell does not contain its own fuel therefore fuel storage and delivery system are very important to a successful system. One of the first questions that needs to be addressed is whether the fuel cell will operate on hydrogen, reformed fuel, or direct methanol. Another important question is whether the system will be active or passive with regard to the oxidant. 

Using a direct methanol system may improve the energy density of the power supply and make fuel storage easier, though at the cost of increased complexity within the fuel cell. The open circuit of the DMFC decreases with the concentration of methanol feed to the anode owing to methanol crossover and leads to lower performance at low current density because of methanol oxidation at the cathode. However, at a high... 

PEM fuel cells operate with hydrogen. At the moment, there is no hydrogen storage available which is suitable for miniature applications. For direct methanol fuel cells (DMFCs) a better storage opportunity exists in form of methanol cartridges. 

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