Electric Automotive Vehicle

(also, electric motor car, battery-driven vehicle), a street vehicle with a traction motor powered by storage batteries. Generally lead-acid or nickel-iron batteries are used.

In the early 20th century, electric automotive vehicles were used in Western Europe and in the USA as taxicabs, postal vans, public transportation vehicles, and passenger cars. The first self-propelled vehicle in Russia, built in 1899 by I. Romanov, was powered by storage batteries. The first vehicle to achieve a speed of 100 km/hr was an electric automobile built in 1898 by C. Jenatzy in France.

Although the electric automotive vehicle was smokeless, noiseless, and easy to drive, its popularity was restricted by its limited speed and operating range, which were due to the batteries’ low energy density (approximately 20 watt-hours per kilogram [W = hr/kg]) and excessive weight. During the 1960’s, however, concern over the increase in air pollution and noise from automobiles with internal combustion engines prompted wider use of electric automotive vehicles in cities, where the average daily mileage of a vehicle is no more than 100 km, where speed limits are 60 km/hr or less, and where it is feasible to set up a network of stations for charging storage batteries. The energy density of storage batteries has increased to 50 W = hr/kg, and that of nickel-zinc batteries and other types that are being prepared for mass production has even reached 100 W = hr/kg. It has been predicted that the electric automotive vehicle will play a leading role in urban transportation by the end of the 20th century.

Figure 1. Schematic diagram of the Soviet electric automotive vehicle designed by the State Scientific Research Institute of Motor Transport: (1) accelerator, (2) on-off switch, (3) charging receptacle, (4) auxiliary storage battery, (5) traction motor, (6) transmission reduction gearing, (7) motive-power storage batteries and their compartments; the lot produced units used are shown in heavy black

Designed for use in an urban setting, the modern electric automotive vehicle has lightweight running gear and a lightweight body that compensate for the weight of its batteries. It has a special transmission whose placement facilitates replacement of the batteries. The current from the batteries, which are generally located in one or two compartments under the body of the vehicle, flows to the motor through a system of control units that contain thyristors. If an AC motor is used, the system includes a converter. The motor may be mounted either in the front or the rear in unit with the driving axle or in the front with a drive shaft connecting it to the rear-axle assembly (see Figure 1). If, instead, motors are mounted at the wheels, there are either two or four of them. The power supply in most electric automotive vehicles is replenished by replacing the storage batteries, which are removed with special dollies.

Prototypes of electric automotive vehicles used for transporting food products and carrying mail in large cities have been designed in the USSR. With power supplied by lead-acid batteries, vehicles with a carrying capacity of 500 kg have an operating range of 80 km (before the batteries must be recharged) and can accelerate to speeds of up to 70 km/hr. Vehicles designed by the All-Union Scientific Research Institute of Electromechanics and certain foreign electric automotive vehicles have devices that regenerate electric power—for example, during regenerative braking or while the vehicle is traveling downhill or coasting. Many are also equipped so that the batteries may be recharged, without being removed, at urban locations with three-phase power-supply systems.

Figure 2. A Daimler-Benz hybrid electric bus: (1) motive-power storage batteries and their compartments, (2) control units, (3) reduction gearing, (4) traction motor, (5) auxiliary motor and traction-motor cooling fan, (6) diesel engine and electric generator, (7) compressor for steering booster, (8) ventilation apparatus for batteries

The motor of an electric automotive vehicle is sometimes coupled with an automatic transmission that regulates tractive effort and speed. Such a combination eliminates the need for complicated start-control devices. In addition to an internal-combustion engine that produces a constant, low level of pollution, hybrid electric automotive vehicles have a generator, a traction motor driven by the generator, and a small storage battery (Figure 2). The internal-combustion engine is used to move the vehicle at a steady speed and to recharge the storage battery. The storage battery serves as an auxiliary source of power used in accelerating, climbing grades, and passing. The popularity of the hybrids has been limited by their complexity and their use of an internal-combustion engine, its low pollution-production notwithstanding.

In addition to preventing air pollution and reducing noise in cities, the use of electric automotive vehicles makes possible economies in liquid fuels.