From Honda press: Honda has always worked to develop cleaner powertrains as demonstrated by its improved combustion technology for gasoline engines, electric cars, natural gas vehicles and hybrid vehicles. As part of this ongoing challenge, and faced with the need to find solutions to global warming, atmospheric pollution, depletion of fossil fuel resources, and other environmental problems, we turned to hydrogen as an energy source. Hydrogen is attractive not only in that it produces no CO2 or other harmful emissions, but also because it is not a fossil fuel.
Our goal was to create a powertrain built around the fuel cell, which provides the ultimate in green performance by combining hydrogen and oxygen in a chemical reaction that produces electricity and water as the only byproduct then install this powertrain in a fuel cell vehicle that exhibits superb energy efficiency, driving performance, comfort and safety.
The powertrain utilizes a high-pressure, pure-hydrogen type fuel cell system in combination with Honda's own originally developed ultra-capacitor to power an electric motor drive. Besides eliminating emissions of CO2 and other harmful substances, we also applied existing Honda technologies, including EV (electric vehicle) electric drive technology, NGV (natural gas vehicle) high-pressure gas storage technology, and advanced energy management technology used in our hybrid vehicle, to achieve greater energy efficiency. The result was a vehicle with the performance similar to a gasoline-engine vehicle.
A fuel cell vehicle is powered by an electric motor running on electricity generated by a fuel cell stack using hydrogen as its energy source. There are a number of methods for creating such a powertrain. The principal methods for supplying the hydrogen include those in which it is stored directly onboard the vehicle and those in which a reformer is used to convert methanol or gasoline into hydrogen. There are also various methods for storing hydrogen onboard the vehicle. In terms of power supply, some systems use power output from the fuel cell stack alone to drive the motor, while others supplement the FC stack output with an assist device using a battery or capacitor. After considering a variety of factors, such as energy efficiency during power generation and driving, overall system weight, and packaging efficiency, Honda decided to equip the FCX with a system that combines a fuel cell stack and ultra-capacitor with an onboard high-pressure hydrogen tank.
The powertrain of a fuel cell vehicle has more components than a gasoline-powered vehicle does, and they weigh more and take up more space. On the other hand, components apart from the drive mechanism can be laid out freely, and their positioning has a significant effect on the car's performance. For the FCX, Honda developed a custom platform for optimum positioning of the various components, while making each one as compact and lightweight as possible. Starting with the FC stack, which is the heaviest component, power-generating equipment was centrally located under the floor, while the hydrogen tank was tucked beneath the rear seat and the ultra-capacitor installed behind the rear seat. This layout significantly contributes to comfort and performance by ensuring plenty of cabin space while at the same time achieving a low center of gravity and the optimum front-rear weight distribution for a front-wheel-drive vehicle.