This year's Australian national Dyson Award winner tells us more about the bolt-on REVR retrofit kit he's developing, that aims to convert ICE cars to practical, efficient hybrids for less than US$3,200, taking less than a day to install.
It sounds like a bonkers proposition from the outset, but RMIT University design student Alexander Burton is well into prototyping the most mechanically complex part of the system: the flat, power-dense, liquid-cooled 50-kW motor designed to sandwich in between your wheel and brake disc.
It's a pancake-style axial flux motor; the stator is a flat plate that bolts to stationary points on the back of the wheel hub. The rotor is a second flat plate that delivers torque through the wheel bolts. There'll need to be an adapter plate built to suit each car model, but it shouldn't be complex, and motor installation should be a 10-minute job requiring no specialist knowledge.
The battery pack, along with the motor controllers, will go in the well in the trunk where your spare tire would normally fit. "Similarly to new electric vehicles such as Teslas," Burton tells us over email, "we see the spare tire being removed entirely – however, it's up to the customer what they want to do."
That round space should allow room for about a 15-kWh battery pack, which Burton says is enough for more than 100 km (62 miles) of all-electric range at stop-start city driving speeds, using regenerative braking. So it'd handle the vast majority of daily driving for most folks.
The REVR (Rapid Electric Vehicle Retrofits) kit leaves the vast majority of the car as it was; it's designed to run either in parallel with your combustion engine, or without it turned on. You'll turn the ignition key as far as "on" and hit a separate switch to enable the electric drive, or turn the key a little further if you want to start the combustion engine as well.
If the ICE engine isn't running, the big battery pack will keep your regular 12-V battery topped up to run your headlights and 12-V electrics. And where there's things like air con, heating, power steering or brake boosters running off belts from the engine, the kit will include electric replacements or augmentations.
How will it plumb in to read the accelerator pedal? Burton isn't 100% sure yet.
"The simple solution," he tells us, "is a potentiometer or similar device that reads the accelerator input. From this data, both acceleration and regenerative braking is decided, similar to existing hybrid vehicles. We leave the hydraulic braking alone to this is always available to the driver."
The system will likely need some way to shut off or the electric motor when the car's put in reverse, as well.
Will there be some kind of dash display showing your battery level?
"For a basic conversion, we aren't planning one," says Burton. "Diagnostics may be accessed through your phone, but simplicity is the key here."
"The goal is to offer a zero footprint retrofit," Burton adds. "Our target will be about 20% of all mainstream car models, starting with the biggies: Corolla group, Accord group and Civic group. We're looking at a popular BMW. We see installation being carried out by local mechanic workshops that have been trained by us. REVR is a largely bolt-on solution with minimal actual mods to the car."
Target pricing for a fully installed dual-motor, 15-kWh kit is under AU$5,000 (US$3,200) – which, if it works, would be an absolute no-brainer for a lot of car owners.
"This is an optimistic future price point based on wide rollout and falling materials prices," cautions Burton, "but we see the kit being installed for under AU$10k (US$5,400) sooner."
Will it be a legal modification to your car? "This needs to be navigated," Burton tells us, "but updated legislation should allow it, some engineering certification will be needed which we may provide in house."
The first car to be converted will be Burton's own 2001 Corolla, within a few months. Right now, he's still working on prototyping the motor. "Development-wise, we're aiming for a kit to be available in Q3 next year," he tells us.
"The company has a patent pending," he continues. "We have had a lot of people reach out asking for opportunities to invest and crowd-fund so we are hoping to take them up on that in the coming months. Converting the Corolla is the top priority at the moment but we are looking at possible partnerships and directions REVR can go in as well. The stretch goal is to convert one million cars!"
Burton doesn't see the REVR as a performance-boosting modification, despite the fact that it'll clearly deliver a meaty torque boost.
"It is exciting to contemplate how REVR can make a poor man's Koenigsegg and combine torque from all motors," he tells us, "but this will be explored later as it has safety implications."
While a minimally-invasive 15-kWh kit is first priority, Burton hopes to expand things down the track to the point where drivers could choose to completely remove their engines and go fully electric. A full electric conversion with a larger battery pack would of course cost more – but thanks to its modular, minimalist structure, it should be a ton less costly than your average EV conversion.
And that's the point; creating a quick and relatively easy way for people to decarbonize their driving without dropping a stack on a new EV or hybrid.
It's a noble idea – but Burton's clearly got some challenges ahead developing this into a system that's reliable, safe, functional and legal, and that works across a useful range of existing car models. We look forward to following his progress.
Source: REVR
