A review of experimental studies on deposits in the combustion chambers of internal combustion engines

Abstract

This article reviews experimental studies on deposits in engine combustion chambers, with emphasis on deposit composition, damage to engines, formation mechanisms and study methods. The existence of combustion chamber deposits will definitely influence performance and emissions of engines, and is inevitable with the use of petroleum fuel and lubricating oil. These all make it necessary to study the formation, composition, structure and influential factors of deposits, which will provide the basis for reducing deposits in engines. Influential factors and methods of reducing deposit formation are also included. First, the deposit damage to engines is briefly introduced, with a focus mainly on the decline in engine performance and the deterioration of emissions, and the reasons for these phenomena are explained. Next, conclusions on deposit research approaches to their chemical composition and physical structure are drawn. Finally, with regards to deposit formation in gasoline and diesel engines, deposit composition and factors influencing deposit formation, such as engine type, fuel type, oil type, additives, exhaust gas recirculation, etc., are enumerated through experimental studies on engines. Studies on deposit formation with some newly developed types of fuel are also included. The mechanism of deposit formation under these different conditions is explained, and the methods for reducing deposit formation are summarized.