Non-polluting Automobiles

The advantages/disadvantages of energy storage devices, which can provide nonpolluting automobile systems are discussed. Four types of storage devices are identified: electro-chemical (batteries) hydrogen electro-mechanical (flywheels) Molten salt heat storage A high speed flywheel with a small permanent magnet motor/generator has more advantages than any of the other systems and might become a real competitor to the internal combustion engine. A flywheel/motor/generator system for automobiles becomes now practical, because of the technological advances in materials, bearings and solid state control circuits. The motor of choice is the squirrel cage induction motor, specially designed for automobile applications. Some of the special design considerations are: high speed (up to 16000 rpm), high break-down torque, 83% coil pitch, stranded stator copper wire, and special cooling arrangements. The preferred controller for the induction motor is a forced commutated cyclo-converter, which transforms a variable voltage/variable frequency source into a controlled variable-voltage/variable-frequency supply. A modulation strategy of the cyclo-converter elements will be selected to maintain a unity input displacement factor (power factor) under all conditions of loads voltages and frequencies. The system is similar to that of the existing automobile, if only one motor is used: Master controller Controller motor gears (fixed) differential-wheels. In case of two motors, the mechanical differential is replaced by an electric one: Master controller Controller motor gears (fixed) wheel. A four wheel drive vehicle is obtained when four motors with their own controllers are used.