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Protean Electric’s retrofitted through-the-road plug-in hybrid van showing significant fuel economy gains

Protean Electric’s through-the-road hybrid van. Click to enlarge.

A European-based Vauxhall Vivaro van retrofitted with Protean Electric’s electric wheel motors (earlier post)applied in a through-the-road plug-in hybrid system (TTRH) has shown a more than three-fold improvement in fuel economy in hybrid mode over a conventional Vivaro on the New European Driving Cycle (NEDC).

Protean Electric and Millbrook Proving Ground partnered to produce the Vivaro diesel hybrid. The vehicle is being shown for the first time in North America at the Center for Automotive Research Management Briefing Seminar, 1–4 Aug. in Traverse City, Mich. The retrofitted Vivaro has been shown at the 2011 Michelin Challenge Bibendum in Berlin and the eCarTec show in Munich, Germany.

This Vivaro through-the-road hybrid vehicle demonstrates a practical, cost-effective and efficient way to retrofit a commercial vehicle into a plug-in parallel hybrid by simply adding two in-wheel motors and a battery. 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 Chairman and CEO Bob Purcell

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 N·m) peak and 740 lb-ft (1,000 N·m) continuous at the rear wheels.

Each motor has a built-in inverter, control electronics and software. Protean’s in-wheel motors are based on a modular redundant architecture, in which individual autonomous submotors are controlled by associated micro-inverters and work cooperatively to deliver the total power and torque or the motor as a whole.

In addition, Protean added a 21 kWh battery pack, 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/100 km) operating over the NEDC, more than three times the fuel economy of the conventional vehicle, Protean said.

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 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 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.

Bob Purcell



Excellent example of a new age press release with energy benefits and savings at the center. Only ONE mention of old CO2!!!



This is a real accomplishment with a common sense hybridization retrofit. Similar upgrade-retrofit could be done on most if not all existing delivery vehicles (taxis and city buses) for major reduction in imported fuel consumption.

Lighter vehicles could have a much smaller ICE and smaller battery pack to lower cost.


Many what-if design questions occur to me. For example, what if the front powertrain were removed and equivalent weight in batteries were put in? ie what range would result. The torgue of the electric drive suggests its overpowered at 740 ft lbs continuous; could it be downsized.

Nick Lyons

@nordic: Torque is not multiplied by transmission and rear end gears, so higher torque is needed for in-wheel motors.


Why would a makeshift conversion be a better value than a purpose built EV?

It's like buying a Corolla and installing a THS from a Prius.

Fun and exciting, but expensive.

And uneconomical, overall.

william g irwin

But suppose you already had a fleet of 'corollas' - or delivery trucks. This retro could convert a substantial percentage of our US fleet to high mileage quickly without replacing it all. If it pans out, I would expect UPS, FedEx, USPS, etc. would jump on it.
Well - depending on price anyhow. No mention of that. I would love more info on this motor - cooling, mounting, etc.


" . . depending on price .."

Ya think?


Is it more effective to subsidize massive retrofits (similar to the one mentioned above) or the purchase of new more efficient vehicles?

Local retrofits would certainly create many more jobs than imported electrified vehicles. Retrofitting large Hummer like gas guzzlers may have more effects on gas consumption.


"Fleet operators should be lining up for a vehicle such as this . . ."


OK. Then pay them to.

But use only money from the budget excess -


As Doyle and Biden say “We have negotiated with terrorists. This small group of terrorists have made it impossible to spend any money.”


TT: What is the best long term investment:

1..Borrow $1000++B to continue to pay for imported crude oil to run our 100+ million gas guzzlers.

2. Borrow $1000+B to promote the wide use of more efficient vehicles.

Oil producing countries may be reluctant to loan $$$$B for No. 2.

I would put by $2 on No. 2.

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