Unbalance and Balancing of the 4 Cylinder Engine: A Critical Analysis of Literature

Abstract

The 4 cylinder 4 stroke engine is the most widely used IC engine type for cars, light and medium commerical vehicles and tractors as well as for small and medium stationary applications. These engines work with either the Otto (spark ignition) or Diesel (compression ignition) operation cycles. The large scale of application is the reason why this engine type has been considered at great length in the literature and why its problems of free mass forces balancing have played an important roll, especially when the engines are fast running. Unfortunately, the natural dynamic unbalance of this engine type and the measures to minimize its effects have neither
been uniformly nor always correctly described and treated in the literature available at the Faculty of Technology of the Addis Ababa University.

Therefore a summary of the theoretical background and its simplifyed practical approach is given first. Important statements from the concerned literature are critically analyzed. Different possibilities for arranging balancing shafts in engines are showm A simple model was developed and manufactured that can be advantageously used for demonstrations in class, to show the effects of reciprocating elements of different multi cylinder engine types.