Left and right wings can move separately
In aerobatics, the maximum roll rate for an aircraft is said to be 720 degrees per second, or in other words, two full rolls. But certain types of wings actually allow a bird to roll over 5,000 degrees per second. If, like birds, we could control the left and right wings to flap separately, imagine the freedom is would give to a plane in flight.
Actually, this kind of technology is being developed for automobiles. Only, with cars, it’s not for separately controlling wings, but wheels. By controlling the left and right wheels and their drive force independently, the vehicle responds closer to the driver’s intentions more than ever before.
Delivering what the driver does, faster
To do this, there is a technology called the in-wheel motor, which integrates a motor with the wheel, driving them by electricity supplied by lithium-ion batteries. In other words, it’s a kind of electric vehicle (EV). At present, Nissan is developing cars that utilize in-wheel motors for the two rear wheels.
There are two reasons why by using the in-wheel motors to individually control the left and right wheels, the car is then able to respond better to how the driver wants it to behave.
First, the respective drive force for the left and right wheels can be increased or decreased independently.
For example, when turning left, the drive force for the left rear wheel could be decreased and slowed down as per how the driver is steering, while the drive force for the right rear wheel could be increased and accelerated. This adds to the power produced by the front wheels changing the direction of the car, while the power created by the difference between left and right wheel speeds also works as power for altering vehicle direction. By utilizing the performance of the front and back wheels, responsiveness is faster than that of conventional vehicles. As a result, the driver is able to control the car better around a curve.
Technology for independently controlling braking on the car’s wheels has existed for some time. However, the in-wheel motor does not only reduce wheel speed, but can also increase it, allowing for freer control of how the vehicle moves.
The second reason an in-wheel motor provides responsiveness is that motor power can be transferred to the wheels faster. Electric motors are able to increase and decrease power faster than gasoline engines, meaning that the EV Nissan LEAF’s initial off-the-line acceleration is very swift and smooth. The in-wheel motor adds to the merits of the electric motor, making it possible to change the motor force being transferred to the wheels even faster. Let’s compare the LEAF and in-wheel motor.
A Nissan LEAF stores its motor where a car keeps its gasoline engine—under the hood. The power from the motor is transferred to the wheels via the drive shaft, but doing this rotates the drive shaft. On the other hand, an in-wheel motor is located right by the tires, so its drive shaft is extremely small and the amount of force needed to rotate the drive shaft is also very slight. This means that the motor power can be transferred to the wheels instantly, giving a driver meticulous and responsive command of the vehicle, while maximizing independent control of the left and right wheels. As a result, the car moves and behaves just as the driver wants.
New possibilities for cars
Needless to say, in-wheel motor technology is not suitable for every car. Placing the conventional motor like the Nissan LEAF’s in the same location as a gasoline engine was one of the solutions for how to manufacture EVs that are relatively inexpensive.
Conventional high-performance cars have more powerful engines with real capabilities. No mistake about it, these cars are very attractive to drive. But drive a car with in-wheel motor technology and you will realize a new kind of attraction. It’s a driving experience that feels like you are truly one with the vehicle.
High-performance that brings the car and the driver closer together: this is the new model of mobility revealed by in-wheel motor technology.