Energy Solutions - AutoWorld.Com

"Nissan is committed to the harmonious coexistence of automobiles, people and nature," said Mike Seergy, vice president and general manager, Nissan Division. "We are testing a broad range of alternative energy technologies in order to expand environmentally friendly consumer options in the future."

Following is an overview of some current Nissan alternative energy concept vehicles:

The all-new Nissan Altra EV, a stylish, four-passenger minivan, is the first production EV in the United States to use Li-ion batteries, the same superior power source used in high-end notebook computers and video recorders. The lightweight, energy-efficient Li-ion batteries provide the Altra EV with a useful driving range of 80 to 100 miles.

The Nissan Hypermini is an ultra small electric vehicle which aims to set a new standard for personal mobility and enjoyment in urban motoring for the 21 st Century.

The Hypermini is designed especially for short trips by one or two people, making such travel highly convenient, enjoyable and comfortable. Engineered for everyday use, the Hypermini is ideal for commuting, picking up and dropping off passengers, shopping and a host of other situations. As an ultra small EV, the Hypermini proposes a totally new approach to urban motoring that transcends conventional notions of the automobile.

The vehicle dimensions have been reduced as much as possible to create a convenient size eminently suitable for use in everyday life. Traffic survey data indicate that approximately 90 percent of all passenger cars are driven less than 45 miles a day and that roughly 90 percent of mini-vehicles, which are used on weekdays, have only one or two occupants. There is also an increasing trend toward multiple vehicle ownership. Designed with these trends in mind, the Hyperrnini is equipped with a large enough battery pack for practical use in daily life, while featuring a much smaller size and lower cost.

A hybrid electric vehicle (HEV) is one that includes two or more power sources. Nissan is developing HEVs that combine a gasoline engine with an electric traction motor to synergize their respective advantages for dramatic reductions in fuel consumption and exhaust emissions. Hybrid electric vehicles can be configured either as a series system or as a parallel system.

Series HEV: In a series HEV, a gasoline engine powers a generator to produce electricity for running a traction motor that drives the wheels. The engine can be operated at high efficiency in terms of torque and speed because it is only used to drive the generator. Since the wheels are driven only by the electric traction motor, the vehicles can be operated as a pure EV with the engine shut off and provide a driving range of approximately 30 miles on a full battery charge. Moreover, the motor functions as a generator during regenerative braking to convert braking energy into electricity that is stored in the batteries,

Parallel HEV: The parallel HEV has two power sources - an engine and an electric traction motor - to drive the wheels. Nissan has developed its own parallel hybrid system which is paired with a continuous variable transmission (CVT).

The system is designed so that propulsion is provided via the CVT in the range of good engine efficiency and the electric traction motor is automatically activated where engine efficiency is poor, such as during idling and low-load operation. During regenerative braking, the engine functions as a generator to convert braking energy into electricity that is stored in the batteries. Moreover, Nissan is now developing a thermoelectric power generation system for recovering the thermal energy that is ordinarily released into the atmosphere in the exhaust gas.

Electrolysis of water produces hydrogen and oxygen, whereas the reaction of these two elements yields electricity. A fuel cell makes use of these electrochemical reactions to convert the energy contained in a fuel directly into electricity. Fuel cells have attracted a great deal of interest from the standpoint of environmental protection because they emit only water vapor.

The gaseous nature of hydrogen would present various refueling complications at conventional service stations that handle petroleum-based liquid fuels. Additionally, storing a hydrogen cylinder on-board a vehicle would also pose safety issues that must be resolved. As a potential solution to these problems, Nissan is focusing on methanol which exists as a liquid state. Nissan has developed a system that uses a methanol reformer to produce hydrogen by decomposing methanol and water. Using this method to produce hydrogen makes it possible to dramatically extend the driving range compared with the on-board storage of hydrogen in a tank having the same capacity.

Nissan's fuel cell-powered vehicle combines this fuel cell technology with Nissan's own high power-density Li-ion battery and neodynium magnet synchronous motor that drives the wheels and also functions as a generator during regenerative braking. As a result, together with the high efficiency of the fuel cell, fuel economy is improved by more than 50 percent over conventional gasoline vehicles.

Moreover, because of their compact size, the Li-ion battery pack and the fuel cell do not compromise interior spaciousness. While the exhaust gas contains C02, the amount emitted can be reduced to less than one-half the level for conventional gasoline engine vehicles. A further advantage is that methanol is not derived from petroleum, so it will not be affected by the future depletion of oil resources.

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