The viable environmental car is defined, candidate solutions are reviewed, and an explanation of the recommended solution is presented. The recommended solution, termed “Unlimited Electric,” is the fruit of a study of US driving patterns, target vehicle efficiencies, and advanced battery technologies. Further rationale is derived from the benefits of the vehicle and the avoidance of key consumer burdens associated with many advanced propulsion technologies.
The recommended solution is a light, aerodynamic, four-passenger, hybrid vehicle having electric propulsion as the source of acceleration power. Local travel can be performed with zero emissions and there is no need of new fuels or major infrastructure. Energy for long range travel is provided by a small, ultra-low emission, gasoline powered auxiliary power unit integrated with the vehicle. The combustion engine operates when needed for long trips at a relatively constant power and allows time for a substantial engine starting cycle to minimize emissions.
The vehicle is typically operated as electric-only on 90% of days, recharging overnight. Exhaust emissions are zero within urban areas where the air quality concern is the greatest. Fuel combustion occurs during only about 27% of the annual vehicle kilometers (normally outside urban areas) and the vehicle has a high efficiency, making the lifetime petroleum-based fuel usage about one-sixth that of a CAFE equivalent vehicle. A comprehensive comparison suggests the concept to be the most viable environmental vehicle of five types reviewed.