Mercedes-Benz carries out comprehensive entire-vehicle endurance testing not just before start up of totally new model series but also in the case of facelift measures such as with the extensively updated C-Class. The Mercedes test drivers covered the length and breadth of many different countries – on testing grounds, in city traffic, along dust tracks and over frozen lakes. The amount of effort involved is enormous, but it is unavoidable: this is the only way to ensure the reliability and durability of a Mercedes-Benz.
Endurance testing includes a series of long-distance tests in everyday traffic and on testing grounds, and in each case the focus is on certain components or functions. The work involves running through a car’s entire lifetime in fast motion, simulating the loads and stresses that a Mercedes-Benz has to withstand over the course of many years. The tests themselves are accordingly challenging: what is known as the time acceleration factor is between 1:150 and 1:2, depending on the test in question, so in the case of the former, 2000 test kilometres correspond to the everyday stresses of 300,000 kilometres with the Mercedes customers on average.
The endurance testing includes:
Full-throttle endurance tests
Trailer endurance tests
Worldwide endurance trial in Namibia
In-camera testing on the Swabian Jura (for details of this
please see the next chapter, “Under the microscope”)
The new-generation C-Class undertook the full-throttle endurance tests on a testing site in the North of Germany and on a high-speed track in Italy. This involved the C-Class models covering 50,000 kilometres virtually non-stop – interrupted only by refuelling stops and for driver and tyre changes. Focal points of the testing included the cooling of the engine and brakes, taking into account the air flow through the new shock absorbers.
The stresses applied during trailer endurance testing, which Mercedes-Benz performs on the Swabian Jura, are no less tough. With the maximum payload and the highest possible trailer load the test vehicles cover many thousands of kilometres on the steep, winding roads of this low mountain range in South Germany, with the vehicle structure and drive system being subjected to the harshest loads. Afterwards the Mercedes engineers disassemble and examine down to the last detail components which have borne the brunt of particularly hefty stresses, such as the rear axle gear.
The worldwide endurance trial in Namibia also has some extreme stages to offer. In the highlands and the Namib Desert the Mercedes test vehicles have to cope with gradients of up to 23 percent and passes above the 2000 metre mark as well as stone, dust and gravel tracks. It is not just the suspension that has to prove its Mercedes qualities; the body, installation parts in the interior, climate control and door seals are subjected to huge stresses due to the constant vibratory excitations.