Producing a vehicle that uses in-wheel electric motors is a process that's a lot more complex than just tearing out the engine and then cramming electric motors into the unused space inside the wheel. This type of electric motor is designed to work on hybrid vehicles, full battery-operated vehicles and even fuel-cell-powered electric vehicles.
The amount of power generated by these in-wheel motors can vary depending on the manufacturer and the size of the motor. For example, a company called Protean Electric unveiled a Ford F 150 truck at the Specialty Equipment Market Association (SEMA) show in 2008. Protean modified the Ford F-150 EV by removing the V8 engine and adding four in-wheel electric motors to the truck. Each of the four Protean Drive motors are capable of delivering over 100 hp each, a total of 400 hp from all four motors -- far more than produced by the standard V8 engine. Each motor weighed only 68 pounds (31 kilograms) and gained power from a 42 kWh lithium-ion battery that provided the truck with a range of 100 miles (161 kilometers) before recharging.
The number of in-wheel motors a vehicle actually uses can be adjusted to meet the vehicle requirements. For instance, in most cases, two motors will supply sufficient power; however, if you're talking about an all-wheel-drive (AWD) vehicle -- either an off-road truck or a performance car -- obviously that would require four in-wheel motors.
Up next, let's take a look at Michelin's Active Wheel system to better understand how this technology functions.