Powertrain

Fuel Cell Vehicles

Fuel cell powered vehicles (FCVs) offer a promising new source of clean power for vehicles.  This innovative technology uses chemical energy rather than combustion to generate electric power, resulting in fewer emissions and a decrease in dependence of foreign oil.

FCVs represent a radical departure from vehicles with conventional internal combustion engines. Like battery-electric vehicles, FCVs are propelled by electric motors.  Fuel cells onboard the vehicle creates electricity through a chemical process using hydrogen fuel and oxygen from the air.  FCVs can be fueled with pure hydrogen gas stored onboard in high-pressure tanks or through hydrogen-rich fuels (methanol, natural gas, or even gasoline) that are converted into hydrogen gas by an onboard device called a "reformer." The byproducts of FCVs are water and heat; while those using hydrogen-rich fuels and a reformer produce only small amounts of air pollutants. In addition, FCVs can be twice as efficient as similarly sized conventional vehicles and may also incorporate other advanced technologies to increase efficiency.  

Pure hydrogen

FCVs can be fueled with pure hydrogen gas stored in onboard fuel tanks. Since hydrogen gas is diffuse, it must be stored in high-pressure tanks in order to store enough to travel reasonable distances on a full tank of fuel. Currently used tanks, which allow hydrogen to be compressed to 5,000 pounds/square inch (psi) of pressure, can only store enough hydrogen gas to allow FCVs to go about 200 miles before refueling. However, manufacturers are designing and testing tanks that will store more hydrogen at a higher pressure.  In addition to onboard storage problems, our current system for getting liquid gasoline to consumers can't be used for gaseous hydrogen. Therefore, new facilities and systems would have to be built, requiring significant time and resources.

Hydrogen-rich fuels

FCVs can also be fueled with hydrogen-rich fuels, such as methanol, natural gas, petroleum distillates, or even gasoline. These fuels must be passed through onboard "reformers" that extract pure hydrogen from the fuel for use in the fuel cell.  The fuels mentioned above contain enough hydrogen to allow FCVs to travel the same distance as a conventional vehicle on a single tank of gas; about 300 to 400 miles. Also, unlike hydrogen gas, liquid fuels like methanol and gasoline wouldn't require a completely new system for delivering fuel to consumers.

Although there are advantages to powering FCVs with these fuels, there are also several disadvantages.

• Onboard reformers add to the complexity, cost, and maintenance demands of a vehicle's fuel cell system.
• If the reformer allows carbon oxides to reach the fuel cell anode, it can gradually decrease the performance of the cell.
• Reformers produce small amounts of greenhouse gases and other air pollutants.