It is the dream of every vehicle developer: the exact, wheel-selective drive control practically in real time. P orsche Engineering has now developed such a system to the point where it is ready for series production.
The fact that all-wheel drive is superior to all other forms of drive for wheeled vehicles has not only been known since Walter Röhrl in the Audi Quattro. The drive power on all fours is not only a perfect solution as a traction guarantee on slippery surfaces, but also the ideal for effective sports driving - the all-wheel drive reduces oversteer and understeer considerably.
Electric all-wheel drive as a compromise solver
However, the mechanical all-wheel drive - a motor drives all the wheels via axle drives - is always a compromise solution, which is also shown by the numerous construction forms for the 4-wheel drive. The simplest variant, the rigidly switchable all-wheel drive, is a pure off-road helper and cannot be used due to the tension in bends on a non-slip surface.
Permanent or so-called' on demand ' -All-wheel drive has other weaknesses to contend with. In general, when cornering, you need the option of speed compensation between the axles and between the wheels of an axle. This in turn means that in the case of an “open” permanent all-wheel drive, a single spinning wheel is enough so that no drive force is applied to any of the other wheels. Various technical tricks can help here. Manually or automatically operated differential locks or the electronically controlled brake intervention are thosebest known of them.
Pure software control
It would of course be much smarter and more effective to let the torque act on each individual wheel that is ideal in the current driving situation. Can also be influenced by the driver if, for example, he is in the mood for swiveling oversteer on the racetrack.
Porsche Engineering has now developed just such a system. Although the customer of the order is not named, it can be assumed that this is the all-wheel drive system of the coming, purely electrically driven Porsche Macan of the second generation. This software-based solution does not require any additional sensors and only uses data from the available sources. The engineers also went unusual ways. In addition to the nearby wheel speed sensors or the measurement data supplied by the electronically controlled chassis, they also use the data from the automatic headlight control to record the current weight distribution.
The newly developed one The Porsche Engineering control system can therefore not only automatically distribute the torque between the axles and via the brake intervention, but also, if necessary, take over the effective control in configurations with four electric drive motors. In doing so, the developers are also going back in time: the world's first all-wheel-drive car was the Lohner-Porsche, with an electric drive and one electric motor per wheel.