Measurement of intake airflow in cylinder diesel engine by industrial computed tomography

Due to invisible and dynamic, the true status of airflow field in engine cylinder is difficult to obtain online and non-destructively. We propose the industrial computed tomography (ICT) image method to analyze intake airflow field in a single diesel engine. First, the intake airflow tomographic image is obtained. Then, tomographic image processing based on the largest average mutual information is used to increase its information. Finally, the extraction of target characteristics tomographic images based on multi-dimensional random variable mutual information and conditional entropy is used to analyze the status information of gas in intake airflow field, such as trace point, density ρ, geometrical shape and its changes. The results demonstrate that, gas density weakens gradually from cylinder wall to the center of the cross section. The chromatography chains of random coil and star topology are formed by the interaction of gases in the flow process. The more far away from the cylinder head, gas micelles flow more stable, and the average density of gas on the cross section is lower.