Audi has drastically reduced internal friction in many of its TDI engines. The methods it has employed to do so include high-end machining technologies in production, such as lasering and plate honing of the cylinder barrel. The even more durable and precise barrels enable the tension forces of the piston rings to be minimized, and so the pistons run even more smoothly. Smaller bearings on the crankshaft, conrods and camshafts are also major factors in reducing friction.
Another area of focus in the developers’ work relates to the materials in the engines. In the new 3.0 TDI, for example, the first piston ring has a coating produced by a new-style technique. The piston pins have a diamond-like carbon (DLC) coating.