By Brian Early
Developing or modifying modern vehicle powertrains requires that a lot of testing occurs. Basic mechanical durability; fuel, spark, and valve control system mapping; shift calibrations, and eventually type certification all demand that hours be spent on a dynamometer. Motors must prove themselves in the lab before ever finding their way under the hood of a test vehicle.
In a rare move, Mercedes gave us an inside look at its state-of-the-art Untertürkheim passenger-car engine test facility here in Stuttgart.
Completed in 2003, Untertürkheim boasts 72 individual engine test benches on three floors. Each test bench is a large room filled with a seemingly random array of ducts, wires, hoses, and equipment. There is sufficient space in these rooms that powertrains can be evaluated with their complete exhaust systems in place, necessary for both development and certification.
The control systems can recreate nearly any imaginable sequence or operating situation – we watched as the entire exhaust system began glowing deep red on one V6 while it performed the equivalent of 230 km/h driving for several minutes. Powertrains are subjected to continual simulations of everything from cold starts to full throttle runs; after 500 hours of operation, each is torn apart and inspected.
The in-house designed (and subsequently patented) rolling palette that each engine and transmission occupies is pre-fitted with myriad electrical and fluid connections that facilitate quick changes of test units and eases test bench set-up.
Fuel for each test room comes from several in-ground tanks, and can be custom blended as needed, eliminating the need for dangerous on-site refuelling.
Computer intensive controls and monitoring mean that tests can be conducted without having technicians present at each workstation. Consequently, Untertürkheim’s testing occurs all day, every day, with a reduced night-time staff required only to keep an eye on things.
Having the ability to evaluate as many engines as thoroughly as this at one time gives Mercedes a competitive advantage, one that company reps hope is borne out by the new V6 and V8 powerplants developed here.