Analysis of an in-line engine crankshaft under the firing condition

摘要

The paper presents a method for analysis of the mechanical behaviour of a crankshaft in a four-cylinder internal combustion engine. The purpose of the analysis was to study the characteristics of the shaft in which the pin and arm parts were assumed to have a uniform section in order to simplify the modal analysis. The results of the natural frequency transfer function and mode shape were compared with those obtained by experimental work. The results obtained from the comparison showed good agreement with each other and consequently verified the analysis model. Furthermore, a prediction of crankshaft characteristics under the firing condition, by using the model, was performed. The study describes a new method for analysing the dynamic behaviour of crankshaft vibrations in the frequency domain based on the initial firing stages. The new method used root mean square values to calculate the energy at each bearing journal and balancer shape modification under the operating conditions.