Characteristics of in-cylinder flow and mixture formation in a high-pressure spray-guided gasoline direct-injection optically accessible engine using PIV measurements and CFD. (15th November 2021)

• Record Type: Journal Article
• Authors: Kim, Donghwan; Shin, Jisoo; Son, Yousang; Park, Sungwook
• Is Part Of: Energy conversion and management. Volume 248(2021)
• Publication Date: 2021-11-15
• Subjects: Spray-guided DI engine -- Optically accessible engine -- In-cylinder flow -- Mixture formation -- PIV measurements -- CFD; Direct energy conversion -- Periodicals; Energy storage -- Periodicals; Energy transfer -- Periodicals; Énergie -- Conversion directe -- Périodiques; Direct energy conversion; Periodicals; 621.3105
• DOI: 10.1016/j.enconman.2021.114819
• Languages: English
• ISSNs: 0196-8904

Abstract

Highlights: Visualization of the in-cylinder flow and spray structure in spray-guided DI engine. Investigation of the interaction between in-cylinder flow and spray structure. Numerical analysis of the mixture formation depending on injection timing. The mixture formation can be divided as homogeneous, stratified and mal distribution depending on injection timing. Abstract: In this study, a spray-guided gasoline direct-injection 2-cylinder optically accessible engine was used to analyze the characteristics of the in-cylinder flow and mixture formation using PIV measurements and computational fluid dynamics (CFD; CONVERGE v2.4). The mean velocity, tumble ratio, turbulent kinetic energy, and tumble center were calculated to quantify the characteristics of the in-cylinder flow. Moreover, flow rotation intensity was defined to evaluate the in-cylinder flow depending on the crank angle. In the early stage of the intake stroke, the intake air flowed into the cylinder with high momentum and velocity. Subsequently, tumble flow was generated in the middle stage of the intake stroke, and weak in-cylinder flow occurred during the compression stroke owing to the dissipation of momentum. The fuel injection caused intensification of the in-cylinder flow, increasing the in-cylinder flow velocity, tumble ratio, and turbulent kinetic energy. Furthermore, mixture formation was affected by the end of the injection timing and its characteristics were classified into homogeneous, stratified, and mal-distribution mixtures, depending on the region to which the end of injection timing belonged.