Automotive crankshaft bearing shells have combination of materials creating a continual or stepped change in the coefficient of thermal expansion

摘要

An automotive piston engine has a crankshaft with two lightweight alloy bearings sections. One or both sections have inserts fabricated from open-pored hybrid ceramic, particulate or fibrous pre-forms into which a lightweight metal or lightweight alloy is cast. The inserts have a socket for the crankshaft. The inserts or pre-forms have an isotropic structure with respect to their composition and/or the pore volume. This structure creates a continual or stepped change in the coefficient of thermal expansion (a). The coefficient of expansion increases from the crankshaft bearing shells towards the surrounding cast components (18, 20).