Patents show how future electric bikes could handle better.By Ben PurvisOctober 9, 2023

If the bike in these patent images looks vaguely familiar, that’s because it has the outline of Honda’s radical, shape-changing Riding Assist-e concept from back in 2017. However, under its skin this is a completely different take on the idea of using the advantages of electric power to improve the motorcycles of the future.

The Riding Assist-e concept was impressive; it could alter its steering-head angle and wheelbase electrically, and in long-wheelbase form could self-balance, even when stationary, by simply using an actuator in the steering to turn the front wheel left or right. With an electric powertrain, it could move forward or backward, while balancing itself, even without a rider aboard. Interesting stuff, but it’s not clear how that ability would be a benefit to most riders.

This new design, while sharing the Riding Assist-e’s styling, has a completely different electric-drive system. There are two separate patents for the concept bike. One pertaining to the two electric motors driving the rear wheel, and a separate one addressing the front-hub-mounted unit. By using computers and inertial measurement units to judge the bike’s angle and attitude, the torque distribution to these motors can be juggled to help its handling and performance.

Let’s start with the two motors at the rear. They’re mounted longitudinally and side by side just under the rider’s seat. They rotate in opposite directions, while each motor is directly connected to a drive shaft running along the bike’s swingarm to the rear wheel. On the face of it that seems unnecessary, but the two contrarotating motors and drive shafts are key to giving this bike cornering capabilities that couldn’t be achieved with more conventional designs.

The idea is to use the torque of the motors to either encourage the bike to lean into a corner or to help stand it up on the way out of a turn. The motor on the left turns clockwise, seen from the rear, while the motor on the right turns counterclockwise. When more torque is applied to the left-hand motor, the torque reaction will try to make the bike lean to the left; if more torque goes to the right-hand one, the bike will try to lean to the right.

Honda’s patent suggests, for instance, that in a left-hand turn, the left motor will be given the most power on the way into the corner, helping the bike to tip in more rapidly. Midcorner, both motors will share the power and deliver torque evenly to maintain stability. And on the exit of the corner, the right-hand motor will be prioritized, creating a reaction force that encourages the bike to return to an upright position.

With Honda already looking at a number of riding-assist systems for the future, including steering assist, it’s clearly a way that street riders and novices could be helped, but also a system that might prove useful in a future world of high-performance electric bikes, even racebikes, by offering handling that couldn’t be achieved or aided using a conventional internal combustion engine.

The third electric motor is described in a second patent, and fits in the hub of the bike’s front wheel. Here it can provide a route to getting more power to the ground than a one-wheel-drive motorcycle can manage, but Honda also sees it as an alternative and advanced form of wheelie control.

At the moment, wheelie control systems are a familiar technology, but they work by reducing power to the rear wheel when the front starts to lift, inevitably putting a limit on acceleration. By using the torque-reaction idea and a motor inside the front hub, Honda thinks it’s possible to control a wheelie without cutting power, giving an outright improvement in acceleration.

Once again, the idea is to use the motor’s rotation to counter the pitching of the bike. To achieve that, the system recognizes when the front wheel has left the ground and is continuing to rise and reverses the front wheel motor to counteract that movement. That means the front wheel will slow, and if the front continues to rise, will stop and then start to spin backward. The result is a force that pushes against the torque that’s trying to lift the front wheel.

Of course, having the front wheel return to earth spinning in the wrong direction would be potentially disastrous. To prevent that, the system recognizes when the front has stopped lifting and is starting to return to earth, cutting power to it or even returning it to forward rotation before it touches down.