Let's learn about the mechanism of FCVs!

The FCV is an environment-friendly car compared with conventional cars that run on gasoline. However, a major obstacle to its popularization is the necessity to construct an infrastructure that includes fuel stations.

Basic Configuration

Fuel cell vehicle (FCV) includes fuel cells which generate electricity by a chemical reaction between hydrogen and oxygen. This electricity rotates an electric motor in the vehicle so that the vehicle moves.
Gasoline engine cars are supplied with gasoline at a gas station. Like these cars, fuel cell vehicles are fueled with hydrogen at a hydrogen station.

Fuel cell vehicle (FCV)'s basic Configuration
Click here to see Hydrogen Stations

Five Features

1.Zero or Near-zero Emission of Harmful Exhaust Gas

Fuel cell vehicles* emit only steam while they are running. They do not discharge carbon dioxide (CO2), nitrogen oxide (NOx), hydrocarbon (HC), carbon monoxide (CO) or particulate matter (PM) at all. They do not discharge harmful air pollutants such as benzene, aldehyde, etc.

※ FCVs running on direct hydrogen fuel cells in which hydrogen is used intact as fuel.

2.High Energy Efficiency

Currently, fuel cell vehicles provide very high energy efficiency (more than 30 %) which is twice the efficiency (15 % to 20 %) attained by gasoline engine cars. Fuel cell vehicles can maintain high efficiency in low-output ranges.

3.Utilization of Various Types of Fuel and Energy

Natural gas, ethanol, and other various types of non-oil fuels are available for fuel cell vehicles. So, they will not be plagued with a fueling problem when oil runs out in the future. In addition, hydrogen can be produced by solar power, biomass, and other clean and renewable energy sources, thereby alleviating the environmental load.

4.Low Noise Levels

Fuel cells generate electricity by an electrochemical reaction. Thus, they produce lower levels of noise than gasoline engine cars. Fuel cell vehicles provide comfort and reduce the city noise.

5.Unnecessary Recharging

Electric cars need time-consuming recharging. On the other hand, fuel cell vehicles can be fully fueled in a short time, like gasoline engine cars. Fuel cell vehicles can cover a longer cruising distance with one refueling than electric cars. This cruising distance is expected to become comparable with that of gasoline engine cars.

Fueling Methods

There are two types of fuel cell vehicles: one with a direct hydrogen system and the other with an on-board reforming system. The direct hydrogen system directly supplies hydrogen from a hydrogen station to fuel cell vehicles. The on-board reforming system supplies fuel other than hydrogen to a fuel cell vehicle which then produces hydrogen through its on-board reformer. The direct hydrogen system is superior in energy efficiency and carbon dioxide (CO2) reduction to the on-board reforming system.

Hydrogen Storage & Mounting Methods

High-pressure hydrogen tank Hydrogen gas, compressed to high pressure (e.g., 35 MPa), is stored in a special high-pressure tank. This tank is mounted on the vehicle.
Hydrogen absorbing alloy Hydrogen is absorbed into a special alloy. This alloy is mounted on the vehicle. Hydrogen is retrieved from this alloy by heating.
Liquid-hydrogen tank Hydrogen is held at an extremely low temperature (-253ºC) and stored in a special heat-insulating tank. This tank is mounted on the vehicle.

Fuels Used

Available fuels for fuel cell vehicles include hydrogen, reformed methanol, reformed gasoline, etc., all of which are currently being investigated.
Hydrogen is expected to find long-term use. However, there are problems with the hydrogen supply systems. Consequently, developers are comparing and investigating the impact of different fuels on the maintainability, management, cost and efficiency of the infrastructure.

Hydrogen ○ Fuel cell vehicles which use hydrogen emit only water and so they are ideal cars featuring zero-emission of exhaust gas.
● There are problems with the storage systems and supply infrastructures for hydrogen.
Methanol ○ Since methanol for fuel cell vehicles is liquid fuel, it can be used like fuel for vehicles with internal-combustion engines.
● Methanol reforming requires heating to about 250ºC. Also required is effective organization of methanol stations.
Gasoline ○ Existing gas stations are available to supply fuel cell vehicles with gasoline. So, it can be used like fuel for vehicles with internal-combustion engines.
● Gasoline reforming requires heating to a higher temperature of about 800ºC. If gasoline includes sulfur, it cannot be reformed easily. In this case, clean hydrocarbon fuel (CHF) is required.

Auxiliary Power Supply

Fuel cell vehicles can run by using fuel cells only. However, a hybrid system is also being developed for fuel cell vehicles. This system combines fuel cells with an auxiliary power supply source such as a dry battery or a capacitor.

Power Source with Fuel Cells Only This power source includes only fuel cells, for system simplification. Unlike the hybrid system, this power source does not recover energy. If the power source uses an on-board reformer, it takes some time to start up. However, it is inexpensive and easy to install in comparison with the hybrid system.
Hybrid System The hybrid system offers enhanced energy efficiency, short startup time and quick response by recovering braking energy in an auxiliary power source. In the future, power sources featuring higher energy efficiency will be preferred. Thus, the systems used are likely to be hybrid systems. However, the hybrid system requires an electricity storage energy device such as a dry battery. Therefore, this system has the disadvantage of being complicated.