Ahead of the launch of the NX later this month, Lexus has revealed a little about how the four-wheel drive system will work on their new crossover vehicle.
Available on the NX 300h, the electric all-wheel drive system provides extra grip only when the driver needs it. Called E-Four, the system uses an additional electric motor to drive the rear axle, providing more grip and better vehicle control on slippery surfaces. The front axle is propelled by power from the hybrid petrol engine or electric motor, or both in combination.
When the system detects a loss of traction to the front wheels, it reduces the electricity supply to the traction motor in the transaxle and increases the supply to the rear axle motor. The amount of power going to the rear wheels is constantly adjusted, depending on driving conditions and, as it’s entirely automatic, the driver doesn’t have to consciously make the switch to 4WD.
As it’s only engaged when needed, fuel is saved under normal conditions. The rear motor also acts as a generator for the regenerative braking system, increasing the amount of kinetic energy that can be stored for use when needed later.
It also avoids the weight, packaging and emissions issues associated with traditional mechanical linkages.
Fitted across the NX 300h range, apart from the entry-level S model, the technology helps towards the model achieving 54.3mpg with emissions of 121g/km. That’s a little behind the figures of a Mini Paceman, but some way ahead of rivals from Audi and Range Rover.