ディーゼル機関におけるPIV測定による筒内スワール流の評価

抄録

The in-cylinder flow in diesel engines significantly affects fuel-air mixing, combustion, and emissions. In the present study, the in-cylinder gas flow velocities in an optical single-cylinder diesel engine were measured using the high speed PIV under different opening area of intake port. Two kinds of intake ports were used which are known as the helical port and the tangential port, and the various experiments were conducted by changing the opening area of helical port. Using the obtained velocity data, the swirl ratio was calculated, which is an index showing the strength of swirl flow, and the center position of the swirl flow was identified during intake and compression strokes. It was found that the center position of swirl flow was moved in the in-cylinder and the opening area of intake ports greatly influences the swirl flow formation. When the opening area of helical port was increased, the center of swirl flow was away from the center of cavity, and the swirl ratio became smaller.