Advances in the Power train System of Honda FCX Clarity Fuel Cell Vehicle

To assist in combating global warming from mobile sources and to respond to energy-dependence on petroleum, Honda has developed the FCX Clarity, a new fuel cell vehicle that displays significant improvements in driving performance and fuel efficiency against previous FCX Models. The FCX Clarity achieves a level of appeal unrivaled by conventional internal combustion engine vehicles. The key to the development of the new vehicle was the reduction of the size and weight of the power train. Honda’s unique V Flow FC stack technology is the core of the FCX Clarity’s fuel cell power train. A considerable reduction in size and weight and increased power have been achieved, with the power train as a whole displaying a weight output density that is two-times higher and volume output density 2.2 times higher than that of the previous FCX. The maximum power of the V Flow FC stack employed in the Clarity has been increased to 100 kW. The new FC stack also achieves a 50% increase in volume output density and 67% increase in weight output density against the previous stack. Low-temperature start performance has also been significantly improved, with the vehicle able to be started at -30°C. A new design has increased the maximum power of the drive motor to 100 kW and resulted in the achievement of a smooth, powerful and continuous acceleration feel. Increased efficiency in the power train and superior energy management have enabled the realization of an energy efficiency of 60%, resulting in a level of fuel efficiency 2.1 times higher than that of a small gasoline vehicle and 1.4 times higher than that of a small hybrid vehicle.