Tech Briefs
Nissan's fuel-cell vehicle with a methanol-reforming system

Nissan's experimental fuel-cell vehicle employs a methanol-hydrogen reformer. On top of the roof is a vent to let out extra steam and hydrogen. The rear passenger/cargo compartment of the FCEV is filled by what one Nissan engineer referred to as a "mini chemical plant." The experimental vehicle is powered by a Ballard fuel-stack pack. Nissan is probing other sources, including its own.

Nissan has a new experimental fuel-cell-powered vehicle with hydrogen sup-plied by an onboard methanol-reforming system, the Nissan FCEV.

According to Eiichi Abe, Vice President and General Manager of the Central Research Center, "Environmental Objectives 3/2/1" are goals that were formulated at Nissan's Environmental Conference. The "3" refers to three times the current mean-fuel efficiency in engines, the "2" twice the torque output, and the "1" signifies that the vehicle tailpipe emissions should be chemically equivalent to the source that powers the vehicle. Technologies put forth at the conference to fulfill these objectives included improved internal combustion engines running on carbon-based fuels and natural gas, electric vehicles, and IC-electric hybrids.

The conference concluded with the decision that the fuel-cell electric vehicle had the strongest long-term feasibility, and that the company would concentrate its research and development efforts on fuel-cell-powered vehicles. The Nissan FCEV is a result of that effort. The experimental vehicle is based on the Nissan R'nessa/Altra EV, which is powered by lithium-ion batteries and operates at approximately 89% efficiency. The on-board methanol-reformer system in the FCEV currently occupies the entire rear-seat and cargo compartments. Phase II will consist of a prototype vehicle with the fuel-cell system, including the methanol reformer, located under the floor to free cabin space for passengers and cargo. By the year 2003, Nissan expects to have completed the research phase of the FCEV, and will move on to the product feasibility phase.

The Nissan FCEV consists of seven key components. The methanol tank has a 40-L (10.5-gal) capacity. The methanol reformer in the experimental vehicle has a capacity of about 80 L (21 gal). The reformer itself is housed in a box-shaped housing, measures 400 x 450 x 550 mm (15.7 x 17.7 x 21.7 in), and has external piping. The total system including the fuel-cell stack is 1.0 x 1.0 x 0.6 m (3.2 x 3.2 x 2.0 ft).

Hydrogen generated by the reformer, and compressed air from the compressor, is fed to the fuel-cell stack. The FCEV compressor is similar to a Lysholm positive-volume compressor made by the affiliated Tochigi Fuji. The propulsion motor, a neodymium permanent magnet, synchronous type, drives the front wheels. It is controlled by a power control unit, which selects between the fuel-cell unit and the lithium-ion battery pack housed under the cabin floor. The battery pack weighs a little over 100 kg (220 lb). The methanol-reformer fuel-cell system requires the assistance of the battery in the start-up process, which remains one of the critical issues in the development of the FCEV. It currently requires 10 to 20 minutes to warm up the reformer before generating hydrogen. Nissan hopes to shorten the process to at least one minute.