Sonification and its application to the study of cyclic variability in combustion in internal combustion engines

Cyclic variability (CV) in combustion has been studied over many years and is still an active area of research. Despite the application of many analytical tools, including, in more recent years, those connected with the study of non-linear dynamic systems, CV remains a challenging subject. In the past, most researchers into CV have presented their findings in the form of overall statistical measures. However, it is felt that perhaps more attention needs to be paid to sequences of combustion cycles on a detailed cycle-to-cycle basis, particularly where the aim is to try to formulate a control mechanism to reduce CV, and that sonification combined with self-similarity plots provides a useful tool to facilitate such an approach. The purpose of this paper is to introduce sonification to automotive engineers, who may be unfamiliar with it, and to give an example of its implementation and application in the study of CV in internal combustion engines.