Parametric study on timing belt wear

Abstract

This Master’s Thesis is based on the "Oulu timing belt disease" and focuses on the wear of the timing belt and pulleys in an internal combustion engine. The thesis is related to a study by the University of Oulu, which investigates the effect of ferrochrome smelter slag (OKTO-aggregate) on the wear of a timing drive test setup. The aim of this thesis is to compare the wear in the test bench and in a combustion engine and to estimate how well they represent each other.

The theory section aims to establish the parameters relevant for timing belt and pulley wear. In the experiments, a simulation model of the test bench and a combustion engine is created, which is then used to evaluate the wear parameters and to compare them between the test bench and a combustion engine.

The results show that the test bench is a sufficient representation of a combustion engine. The simulation predicts that belt life in the test bench would be shorter, since the contact loads and root strain are larger. In the internal combustion engine, abrasive wear is greater due to the higher relative movement between the belt and the pulleys. In reality, the faster abrasive wear in the combustion engine could accelerate other wear mechanisms, reducing belt life compared to the test bench. The results represent a four-cylinder gasoline engine, and subsequent studies could simulate other engine layouts.

The results can be used to evaluate the wear caused by the OKTO-aggregate and to validate previous studies. Additionally, the simulation model and the results can be utilised in other applications dealing with wear of a toothed belt, such as toothed belt transmissions, conveyor belts and packaging lines.