Kolbenschmidt Pierburg Group New Materials and Processes for Passenger Car Diesel Engine Pistons

Thermal and mechanical piston loads The development targets for today’s diesel engines cater to high performance and high torque while curbing fuel consumption. Additionally, exacting demands are made on noise reduction and ride comfort. The aforementioned customer requirements prompt higher mechanical and thermal stresses acting on the piston. The demand for low weight coupled with geometric constraints (low compression height, small pin diameter) for peak pressures of 200 bar and beyond are the drivers for consistent further development of our aluminum materials and the search for new design...

to achieve a further increase in boss load capacity. This solution has been proven in mass production for many years. The changeover to lead-free bushing materials as prescribed by the EU End-of-life Vehicle Ordinance has been largely completed. Diesel pistons made of the new KS Kolbenschmidt alloy V4 are specifically suited to comply with the aforementioned requirements. The aluminum-based alloy will appreciably extend the product life in temperature ranges above 300 °C. This is made possible by a selectively developed alloy composition and a process-controlled microstructure adapted to the...

This will produce an optimized, fine and homogeneous microstructure. This structure improves the thermal fatiguing properties of the critical zone by up to 60 %. Further advantages are higher process stability compared to casting and improved surface quality for finishing. The laser remelting method is a tailored solution that allows a distinct increase in reliability and quality of diesel pistons to be achieved. Piston cooling – DynamiKS® – new piston cooling concepts This is the reason why KS Kolbenschmidt is continuously optimizing its cooling gallery designs. Today’s KS Kolbenschmidt standard...

Outlook The ring carriers in a piston can be used for supporting a specific cooling gallery which consists of a specific-shaped plate welded tight to the ring carrier. This design is particularly appropriate for pistons where high loads require that they have a ceramic fiber reinforcement – FibreKS® – in the piston relief zone. The Squeeze-Cast process needed for this piston type requires fewer cast-in parts but the gallery geometry must be appropriate for the high pressures inherent in this process. Pistons of this design have already demonstrated their functionality in many engine runs. A subject...

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