Alongside crankshafts and connecting rods, Krupp Gerlach GmbH of Homburg an der Saar/Germany has now added rails for common rail systems to its range. The first customer for this product is Robert Bosch GmbH, whose Homburg facility recently took delivery of specimen rails from Gerlach. The Bosch plant manufactures complete fuel injection systems for diesel engines. Once the specimens have been checked and approved, Gerlach expects to receive orders for 500,000 to 750,000 parts over the next two years.

Common rail systems, in which the diesel fuel is injected directly into the combustion chambers of the individual cylinders via a common conduit or rail, ensure optimal, precision-regulated fuel pressure at all times regardless of engine speed. This results in improved engine performance, fuel economy and emissions. With the Euro Level IV exhaust emission standard due to be applied throughout the European Union from 2005, common rail technology will become increasingly important, also for commercial vehicle manufacturers.

Krupp Gerlach forges the rail blanks with connectors and fasteners. Two key innovations in the forging process help cut the time and cost of subsequent machining at Robert Bosch GmbH. The forging die for the rails features an asymmetrical diagonal split as opposed to the common horizontal division. This allows the angled connectors to be made far more accurately and with less excess material than by the conventional method. As a result, the connectors and fasteners need considerably less machining at the Bosch plant. This complex forging technique is supplemented by a new combined deburring and calibrating process. The workpiece is clamped hydraulically in the die for deburring, allowing subsequent hot calibration to be dispensed with completely. Dimensional accuracy is improved to such an extent that whereas 20 to 30 percent of all forgings required post-straightening in the past, now 100 percent of workpieces are to tolerance. In the future Krupp Gerlach will also use this process in the production of connecting rods.

Krupp Gerlach GmbH is part of the Powertrain unit of ThyssenKrupp Automotive.