Mercedes' junior version of the CLS will be offered with the system along with front-wheel-drive models when it goes on sale in Australia in the second half of 2013.
The 4Matic system will also feature on the high-performance CLA45 AMG (pictured below testing), as well as its twin - the upcoming A45 AMG that will top the A-Class range on which the CLA is based.
Mercedes claims its set-up for its FWD-transverse-engine models is lighter than those used by rivals, to the benefit of fuel efficiency, though it’s a variation on part-time AWD systems already employed by a number of car makers, including Mazda and Mitsubishi.
The new 4Matic combines the CLA’s seven-speed dual-clutch gearbox with an integrated Power Take Off Unit (PTU) plus a rear axle gear with integrated electrohydraulic multi-disc clutch.
In regular driving, the multi-disc clutch remains open and the CLA powers along using the front wheels only.
If the vehicle’s stability control system detects the slightest slippage of the front wheels, however, the dual-clutch auto’s PTU directs power to the rear axle – where the multi-disc clutch has now closed.
Mercedes says the torque split between the axles is fully variable, reacting to the available traction between the front and rear wheels.
The torque-on-demand system also adjusts its operation depending on the particular driving mode selected by the driver.
If Eco mode is selected, the system sends less torque to the rear axle. If Sport or Manual modes are chosen, there’s a quicker reaction from the rear axle for more dynamic driving – especially for the AMG version.
This new version of 4Matic will be a natural fit, too, for the Mercedes-Benz GLA, the German car maker’s upcoming small SUV that’s also based on the same architecture as the likes of the A-Class, B-Class and CLA.