Instead of the mechanical link from the steering wheel to the front wheels, the steering wheel is connected to an actuator. An electronic control unit reads the inputs to the actuator. The ECU controls the actuator on the steering rack, which then steers the wheels accordingly.
The system also works in reverse, with the steering rack actuator feeding back what the wheels are doing to the ECU, which then controls the steering wheel actuator, which generates the appropriate ‘feel’ from the road.
Nissan claims that the steer-by-wire system offers a host of benefits, including that torque steer and fight back through the wheel from broken road surfaces becomes a thing of the past.
The system also removes the need for minor steering corrections when driving on the motorway or on a cambered road, as a camera mounted on the windscreen keeps the car tracking in a straight line.
Unlike a lane departure system, the camera is intended to keep the car going straight, however you choose to drive, rather than keeping you in a prescribed lane.
Naturally, driving enthusiasts are expected to be sceptical of the new system. However, Nissan driving control development team member, Takeshi Kimura, says, “Drivers imagine our next generation steering will feel like a video game. So we give them a blind test, conventional power steering versus the new system. Invariably they guess wrong and say that next generation steering offers a more direct and realistic feel of the road.”
What’s more, there are safety implications of the system. However, Nissan says that there are back-up control units, and if power was to fail, there is still a mechanical link in place to the steering rack which is engaged using a small clutch.
Infiniti polled its customers and discovered that steering feedback, particularly from lumps and bumps in the road, was something they disliked, which is why Nissan’s luxury brand will get the technology first, from next year.
Nissan also announced Active Engine Brake for its CVT automatic gearbox. The system offers the electronic equivalent of downchanging when slowing for a corner, giving extra engine braking and thus more control.