Short Cuts – Toyota may not often knock off many socks with the brilliant originality of their cars’ designs;
but that mega-corporation’s engineers regularly come up with inventions that raise the bar on the entire automotive world.
They’ve just done it again with E-Four – a lightweight, intelligent, all-wheel drive system that provides extra grip at the very instant and in the very spot where the driver needs it.
Intelligent all-wheel drive systems that supply torque to individual wheels that may be slipping on ice or sand are now new. For many years, the Swedish company Haldex has been in the forefront of these developments and their excellent systems have graced many contemporary cars, most notably the wonderfully capable all-wheel drive vehicles (such as the Yeti) that have come out of Skoda.
The difference with Toyota’s new E-Four system – to be fitted to the new Lexus NX 300h crossover SUV- is that it brings all-wheel drive to hybrid petrol-electric cars through the addition of an extra electric motor.
In the NX 300h, therefore, the front axle is driven by the petrol engine, the electric motor or a combination of the two – which is the set-up in the Prius. But an extra electric motor can drive the rear axle and produce more grip if the front wheels start to slip. Torque- or pulling power – is automatically supplied to the rear axle as it is needed. The driver need do nothing to bring in the extra power.
The outstanding benefit of this approach is its saving in weight. Conventional all-wheel drive systems add considerable bulk and, consequently, drain fuel. E-Four should help the NX 300h to achieve fuel economy of 54.3mpg with 121g/km CO2 emissions.
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