Increasing fatigue performance of cylinder block snap channel fillet and main bearing cap using a steel insert plate

摘要

In a particular cylinder block assembly 1 consists of main bearing cap 2, assembled to cylinder block 3 using main bolts 4 main bearing shell 5 inserted into main bearing cap housing and cylinder block housing using press fit, due to cyclic engine loads on block snap channel fillet 6 cracked in dyno test. This crack propagated towards cylinder bore causing failure of the engine. Present invention provides solution to reduce stresses on block snap channel fillet 6. The idea is to add a steel insert plate 7 (5mm thick, thickness is not limited to 5mm only) on main bearing cap 2 using main bolts 4 and Center bolt 8. This configuration of steel insert plate 7 along with bolts gives higher stiffness to block assembly. After adding steel insert plate, stresses on block snap channel fillet 6 got reduced and fatigue performance improved by making safety factor to the design requirements. This steel insert plate also helped in increasing fatigue performance of main bearing cap 2 significantly.