The Australian company Evans Electric has developed an electric car that is literally direct drive. It is a 4-door sedan, a Mitsubishi Lancer Evolution, that produces 800 HP/600 kW (peak) and 5,000 Newton-metres (3,688 foot-pounds) of torque.
“While the torque figure could at first glance appear fantastic, standard automotive industry practice only quotes torque at the flywheel not at the wheels,” Evans Electric notes. “As an example the Tesla Model S Performance has a quoted peak motor torque of 600 Nm. With a single speed reduction gear ratio of 9.73:1 that equates to a total of 5,838 Nm (minus gearing losses) at the wheels. The Evans Electric motors are direct drive, so the rotor turns at the same speed as the wheel. Instead of mechanical reduction gearing, they are electrically geared using an 8 pole stator winding configuration.”
To help you understand the significance of that: direct drive equipment has the benefit of mechanical simplicity, and sometimes efficiency, as the alternatives, which are gear-driven systems, waste energy.
Mechanical equipment cannot get any simpler than direct drive. This is because the motor directly turns the wheels itself. In the case of this Lancer Evo 3 vehicle, it has an electric motor integrated into each of the four 19″ (48 cm) wheels. No gears, no transmission, nothing at all.
The most reliable equipment I have ever used is direct drive.
This vehicle can achieve electromagnetic braking. No friction. Friction brakes are inherently inefficient because they dissipate the kinetic energy that moves the vehicle as heat and wastes it until the vehicle slows to a stop.
“The Evans Electric in-wheel motors enable non-contact electromagnetic braking, replacing hydraulic friction brake systems which are 99% redundant in current generation electric/hybrid vehicles. Using only the wheel motors, the car can brake at greater than 1G.”
The Evans Electric in-wheel EV motor, powering a Lancer Evo 3, was just unveiled at Meguiar’s MotorEx at Sydney Olympic Park. Here are some more notes from Evans Electric about its technology:
Evans Electric hold a patent for a vehicle drive system using wheel motors for propulsion and braking, the most impressive feature of which is that safety and vehicle dynamics features such as ABS, stability control, traction control, brake steer, active brake bias, torque vectoring, intelligent cruise control, emergency brake assist and collision avoidance all become customisable and upgradable software functions.
When these systems are combined with wheel motors they allow a new level of performance based active yaw control that unlike most current stability control systems (which only activate in an emergency situation) are active at all times, dynamically fine tuning understeer and oversteer to enhance cornering speed and safety.
After an extensive period of wheel motor validation testing and power electronics development the company has met with several automotive Tier 1 suppliers to discuss collaboration &/or licensing to move the project from proof of concept to commercial product development. Final preparations are under way with track testing expected to commence by the time the Bathurst 1000 rolls around in October.
Notably, this isn’t the first in-wheel electric motor we’ve featured on CleanTechnica. Protean is supposed to be bringing an in-wheel electric motor of its own to market in 2014.