Abstract
In order to improve the performance of diesel/natural gas dual-fuel engine, it is imperative to investigate into its combustion characteristics. The paper presents results of the experiment, which was conducted in an optical testing single-cylinder engine. With the high- speed digital CCD and data acquisition system, ignition, flame development, trace and gradient of in-cylinder pressure were obtained. The experimental results reveal the combustion process of dual-fuel engine actually as the compression ignition of homogenous mixture, and it is seen obviously as premixing burning. Compared with that of diesel, the combustion of dual-fuel lasted shorter and produced less soot, but the combustion pressure and its gradient were higher.