Protean Drive™ is a fully-integrated, direct-drive solution. Each motor has a built-in inverter, control electronics and software – no separate large, heavy and costly inverter required. Direct drive reduces part count, complexity and cost, so there is no need to integrate traditional drive train components such as external gearing, transmissions, drive-shafts, axles and differentials. Protean Drive™ packages easily inside a conventional wheel and can use the original equipment vehicle bearing.
Protean Electric, a leading global supplier of in-wheel electric motors, and Millbrook Proving Ground, one of Europe’s leading vehicle test and demonstration centers, partnered to produce the Vivaro diesel hybrid.
Retrofitting is important because there are 1 billion cars and trucks on the road and there are only 60 million new cars and trucks each year.
“This Vivaro through-the-road hybrid vehicle demonstrates a practical, cost-effective and efficient way to retrofit a commercial vehicle into a plugin parallel hybrid by simply adding two in-wheel motors and a battery,” said Protean Chairman and CEO Bob Purcell. “Our technology is uniquely designed for high-output, high-efficiency operations. Our in-wheel motors are unique in that they have the rotor on the outside and each motor’s electronics on the inside. That simplicity of design creates more power density per motor and much simpler vehicle integration. It’s the closest thing to a bolt-on hybrid system.”
Protean Electric outfitted the front-wheel-drive Vivaro with a through-the-road hybrid conversion kit of two Protean Electric PD-18 motors attached to the rear axle. The two motors together provide torque assist of up to 1,180 lb.-ft. (1,650 Nm) peak and 740 lb.-ft. (1,000 Nm) continuous at the rear wheels.
In addition, Protean added a 21kWh battery, giving the vehicle more than 55 miles (90 km) of electric propulsion range and plug-in hybrid and electric vehicle capabilities. While operating in hybrid mode, the Vivaro measured 114 mpg (2.4 liters/100km) operating over the New European Driving Cycle (NEDC), over three times the fuel economy of the conventional vehicle.
The system can also deliver regenerative braking on the rear wheels with no modifications needed to the existing front brakes while retaining the vehicle’s original engine and drive system. This high level of regenerative braking allows manufacturers to use a smaller battery size or extend the range with the same battery size.
The Vivaro retrofit also allows the driver the unique advantage of being able to switch between multiple operating modes: two- or four-wheel drive operation, IC engine-only drive, electric-only drive, or an electric torque assist Through-The-Road-Hybrid.
The vehicle underwent a rigorous testing regime jointly conducted by Millbrook and Protean Electric. Work is now underway to build a Vivaro Plug-In Parallel Through-The-Road-Hybrid test fleet for select fleet customers.
“Fleet operators should be lining up for a vehicle such as this that will provide more than a 65 percent reduction in fuel usage and CO2 emissions in a typical urban drive-cycle, while enabling electric-only operation for in-city low-emission zones such as London,” Purcell said.