Kolbenschmidt Pierburg Group KS Mono-Block Steel Pistons for Commercial Truck Applications

Introduction The Diesel engine has experienced an astonishing upward trend over the last 20 years for both truck and passenger car applications. This could only be accomplished by continuous innovations in the areas of material science, product design, and manufacturing processes. As a leading developmental partner of the OEMs for pistons and power cylinder modules, KS Kolbenschmidt is constantly redefining the limits of power capability for these components. Requirements Commercial vehicles have the highest demand on total engine life. Besides the associated durability requirements, KS Kolbenschmidt...

The main goals of this piston design are low weight, good cooling capability, good guidance, high robustness, and increased product life. When compared to aluminum pistons, very compact designs can be realized. For example, the compression height can amount to less than 55 percent of the cylinder diameter with a sufficiently shallow bowl. The characteristic design feature of all KS mono-block steel pistons is a long skirt directly connected to the pin boss and the under-crown. This design allows for a transfer of high side forces and a stable guidance in the cylinder bore without compromising...

The design is supported by new development tools like CFD, shaker tests with power cylinder components and an optimization of the piston cooling nozzle using KS in-house rig tests (see Fig. 4 showing connection drill holes and inner chamber cooling). The design of the ring zone, including the top land, is of great importance for reducing oil consumption and blow-by. A cut-back style top land in combination with a tight barrel shape second land and optional oil drainage drill holes has been proven favorable. It has been demonstrated that in the oil ring groove oil consumption is reduced by up...

By installing a partition, an additional cooling chamber is obtained. This technical solution is based on the reliable design for large diameter composite pistons. The oil from the piston cooling nozzles enters the outer cooling gallery as usual through a drilled inlet hole. The necessary amount of oil then passes through the connecting drill holes into the inner cooling chamber. The oil drains via exit holes above the connecting rod, providing lubrication to the small end and pin bores. Fig. 7 shows a section through the monoblock piston with an inner cooling chamber. Utilizing this design reduces...

Axial motion Crank angle in degree Fig. 10: Simulation of ring land pressure, ring motion and blow-by for one cycle With the concepts and characteristics presented for monoblock steel pistons, KS Kolbenschmidt is always able to provide the market with appropriate solutions throughout the full performance output range of engines for commercial vehicles. Various engines are already in volume production with mono-block steel pistons and utilize their benefits. Further projects are underway worldwide in the development phase and will be launched on the market in the coming years. Increased loads...

KS Kolbenschmidt GmbH · Karl-Schmidt-Straße · 74172 Neckarsulm · GERMANY Tel. +49 7132 33-0 · Fax +49 7132 33-2796 · www.kspg.com Subjects to alterations. Printed in Germany. A|I