Design and Analysis of Four Cylinder Crankshaft for Diesel Engine

Abstract

Crankshaft is one of the critical components for the effective and precise working of the internal combustion engine. This converts the reciprocating displacement of the piston in to a rotary motion of the crank. Due to the uneven mass distribution, failure zones occur near fillets and oil-holes in journal locations during the operation of the engine. Fatigue is a phenomenon which occurs due to repetitive loading on the component. Fatigue due to combined bending, and torsion is most common reason for failure of IC engine crankshaft. Crankshafts from two different materials were studied; forged steel alloy 42CrMO4 and micro-alloyed steel 38MnVS6. Micro-alloyed steels are gaining increasing importance as substitutions for carbon steels because they possess higher mechanical properties, such as strength and toughness after hot forging, without a need for post-deformation heat treatment. To increase machinability, sulphur is added to micro-alloyed steels to facilitate chip removal, increase productivity, and enhance the life of cutting tools. Physical testing of crankshaft subjected to combined bending and torsion for evaluation of fatigue life is not a feasible solution because of very high cost of experimentation. The aim of this study is to design the crankshaft for the diesel engine and modeling of the crankshaft is created using Solid Edge ST7 Software & the Fatigue; dynamic analysis is done by using ANSYS. Design of crankshaft consists of the equivalent stress, shear stress, total deformation and no. of life cycles before failure of component.