The Wireless IWM Unit 2 turns a flaw of a electric vehicles into a strength, opening a world of possibilities.

● Electric Vehicles

Since the dawn of the horseless carriage, engineers have been designing cars powered by electricity. But time and time again they could never overcome the raw power offered by the combustion engine. Even today with an environmental calamity at our doorstep, we’ve only gone as far as embracing hybrid vehicles.

The main problem with electric vehicles (EVs) is kind of like the ending sequence of The Flinstones. Fred needs power to keep kick-running his car long distances but to get that power he needs to eat a rack of brontosaurus ribs so big that it tips over the entire car – with mildly amusing results.

In much the same way, electric cars need more and bigger batteries to get enough power to rival the distance gas-powered ones get on a single charge/fill-up. But too big a battery will just weigh them down too much so they would need even more power to move.

Improvements in battery technology have come a long way and are continuing to get better at a rapid pace, but people still don’t seem to be jumping on the EV bandwagon in large numbers yet.

Perhaps what the EV market needs is a whole new type of car which, rather than tries to catch up to the mileage of combustion engine automobiles, surpasses it in every way.

Now, a research group in Japan thinks they may have something.

● In-Wheel Motors

This new vehicle is called the Wireless IWM Unit 2 where IWM stands for “in-wheel motor.”

Most cars on the market use a transmission system where a central engine delivers power to two or four of the wheels through a series of gears and rods. Without getting too technical, in the diagram below, the long thing labeled “torque tube” is turned by the engine and then turns a bunch of doohickeys which then turn the rods that turn the wheels.

Wikipedia/Andy Dingley

Standard transmission systems have their share of weaknesses. All of those turning gears and rods means a fair bit of power is lost and considerable weight is added to the car. Because of their high power, this isn’t big issue for combustion engine cars, but for electric vehicles it’s a huge setback. On the other hand, in-wheel motors have an engine contained right inside the wheel so the maximum power is applied directly.

▼ The rear in-wheel motor of a Honda FCX prototype


Much like electric cars, the concept of in-wheel motors have been around from the very start of automobile manufacturing. One of the most notable examples was the Lohner-Porche Mixte Hybrid from 1900.

▼ These guys rocking a Mixte Hybrid surely had to beat
the women away with a hoop trundling stick.


In-wheel motors were and are superior in many ways, mainly by providing considerably better handling and acceleration making them safer and more comfortable than cars with a transmission. But slapping four combustion engines into such a tiny space simply wasn’t practical, so the in-wheel motor was relegated to bikes, lunar rovers, other types of machinery, and concept cars.

● Wireless IWM Unit 1

In recent years there has been renewed interest in in-wheel motors with the current push for better electric cars. Using them eliminates the need for a bulky transmission and can reduce the weight of the drive unit by 30 to 40 percent. Still, one issue has been that the electricity must be delivered to the wheel from a battery via wires.

▼ The Luka EV is a groundbreaking machine in that it both effectively
utilizes in-wheel motors and is actually a good looking EV.

Luka EV Official Website

Given all the rapid spinning along with the wear and tear that the underside of an automobile goes through, entrusting the power of each wheel to cables is risky. So a team of researchers with the University of Tokyo, the systems engineering firm Toyo Denki, and the mechanical engineers at NSK set out to create a wireless in-wheel motor automobile to completely eliminate the risk of breakage.

The Wireless IWM Unit 1 was a success and could efficiently transmit electric power from a central battery to each wheel’s motor without any wires, allowing for smoother and safer movement.

University of Tokyo

They also utilized “electric road” technology wherein the roads are paved with coils embedded that can wirelessly charge the car’s battery as it drives along. A coil receiver on the bottom of the frame would receive the charge and store it in the battery.

● Wireless IWM Unit 2

However the research group realized that a major weakness of the Wireless IWM Unit 1 was that it followed the power distribution system of regular EVs when it had the potential to be even better.

Rather than relying on a central battery, they fitted each wheel’s motor with another coil to receive the charge provided from electric roads. With this added boost, electric cars can get even more distance out of a single charge, provided there are electric roads.

Toyo Denki (edited by RocketNews24)

This diagram shows how the Wireless IWM Unit 2 works. The in-wheel motor receives electricity from both the battery in the body of the car and from the power grid through coils in the road. The motor will consume power from the road as needed and any excess electricity will be redirected to the charge the main battery. If the car goes off an electric road, then it will use the power of the battery like a regular EV would. As a result, it can travel much farther on a single battery charge.

Toyo Denki (edited by RocketNews24)

Or to put it in Flintstones terms, rather than Fred getting fat off a huge rack of ribs, he can eat a sensible steak and then pick up Fruity Pebbles from the street as he drives either to eat straight away or keep in his pocket for later, thus keeping his weight down and sustaining his energy enough even to participate in the Indianrockolis 500 under the alias Goggles Paesano.

▼ Whether or not we’ll be able to drive on
walls in real life, however, remains to be seen.

With that said, it will still take a lot of different factors coming together for this technology to become widely used, the most important of which would be the installation of electric roads. Sweden and South Korea have both opened stretches of electric roads, but there are construction, operation, and maintenance costs.

But as more designs like the Wireless IWM Unit 2 emerge, the concept of electric roads becomes more attractive and more possibilities open up. Soon the world may finally have an electric car that not only rivals combustion engine ones, but surpasses them.

Source: Toyo Denki, NSK
Top image: Toyo Denki