Considerations on influencing factors of carbon deposit in gasoline direct injection engine

Abstract

This paper describes investigation of the carbon deposit formation phenomenon in Gasoline Direct Injection. A 2.4 L GDI engine and a 2.0 L port fuel injection engine, which were produced by the same manufacturer, were tested on an EC-type engine dynamometer. Non-additized RON 92 regular gasoline was used as the test fuel. The test cycle was based on the ASTM D6201 method, but in the experimental conditions, the average engine load and load-changing frequencies were different. After engine operation, collected carbon deposits were performed on Thermo Gravimetric Analysis (TGA) to investigate the primary source of the carbon deposits. Our investigation revealed that the weight of the carbon deposits on the intake valve and combustion chamber had an inverseproportional relationship with the average engine load on the GDI engine. In addition, the shapes of carbon deposits that formed on the combustion chamber varied as a function of the engine load. The TGA results also showed that the intake valve deposits were largely affected by lubricants, while the carbon deposits in the combustion chamber were mainly generated from gasoline. © 2013 Springer-Verlag Berlin Heidelberg.