Cranktrain modeling and analysis of connection rod vibrational effects on the overall performance of Otto cycle engines

Abstract

Since connecting rods are a major component in the smooth and efficient running of an engine, how they affect the overall performance is important. The durability of connecting rods in repeated and cyclic operations is significant to the health and performance of an engine. The purpose of this research is to determine what effects the vibrations of connecting rods have on the overall performance of Otto cycle engines. Some studies have been conducted on the static vibration of connecting rods as well as connecting rods in dynamic systems, but those studies only considered the connecting rod design. Modeling, dynamic analysis, and vibrational analysis are conducted using two different software programs, MSC Adams/View and FEV Virtual Engine. Two different engine configurations are modeled: inline and vee; the results from the two programs are then compared. The data is also checked against vibrational analysis from literature sources as well as having the general performance of the pistons cross-checked against real engine data. The MSC Adams/ View models are composed of simplified cranktrains and forces; while those of FEV Virtual Engine are modeled after actual dimensions and workings. It is determined that the vibrations of connecting rods, under typical operating conditions and material/geometrical properties, do not greatly affect the overall performance of an engine.