Effects of Port Angle on Scavenging of an Opposed Piston 2-Stroke Engine
2022-01-0707
03/29/2022
- Content
- Opposed-Piston 2-Stroke (OP2S) engines have the potential to achieve higher thermal efficiency than a typical diesel engine. However, the uniflow scavenging process is difficult to control over a wide range of speeds and loads. Scavenging performance is highly sensitive to pressure dynamics, port timings, and port design. This study proposes an analysis of the effects of port angles on the scavenging performance of an opposed-piston 2-stroke engine via simulation. A CFD model of a three-cylinder opposed-piston 2-stroke was developed and validated to experimental data collected by Achates Power Inc. One of the three cylinders was then isolated in a new model and simulated using cycle-averaged and cylinder-averaged initial/boundary conditions. This isolated cylinder model was used to efficiently sweep port angles from 12.5 deg to 30 deg at different pressure ratios. Results indicate that scavenging performance is correlated with the bulk swirl ratio generated by these port angles. Scavenging performance is also sensitive to the pressure ratio across the engine. It was concluded that, for a given pressure ratio, the smallest port angle produces the best scavenging; however, lower bulk swirl ratio during combustion has an impact of emissions formation.
- Citation
- O'Donnell, P., Gandolfo, J., Gainey, B., Vorwerk, E. et al., "Effects of Port Angle on Scavenging of an Opposed Piston 2-Stroke Engine ," SAE Technical Paper 2022-01-0707, 2022, .