In-cylinder gas flow characteristics study of CI engine under motoring and pre-ignition firing conditions using a high-speed PIV

The Interaction between In-Cylinder Turbulent Flow and Flame Front Propagation in an Optical SI Engine Measured by High-Speed PIV

“…The singlecylinder engine uses conventional gasoline fuel delivery through a commercial port-fuel injection (PFI) system. Solid particles composed of SiO 2 (diameter: 4.0 µm) coming from the seeder are injected into the chamber [32]. The scattering of light is captured by a high-resolution double frame camera (HiSense MKII, Dantec) with a resolution of 1280 × 800 pixels per frame and a 12-bit dynamic.…”

“…The optical access into the combustion chamber of the engine is provided by a full quartz liner together with quartz windows on the top of the piston (54 mm diameter) and in the pent roof. The measurement area was focused on the region near the spark plug in the bore center section [32]. The flow distribution and initial flame were measured before and after the compressed TDC.…”

“…Disturbances in the flow occur during combustion and non-combustion, where flame formation and flame spread, along with interference between the flame surface and the turbulence. Many successful approaches for measuring the flow and turbulence in internal combustion engines have been reported [32][33][34][35][36][37][38]. We applied the high-speed PIV technique to measure and evaluate the in-cylinder flow under firing conditions to discuss not only the flow field during intake and compression stroke but also their effect on flame propagation under firing conditions [24][25][26][27][28][29][30][31].…”

Experimental Investigation of the In-Cylinder Flow of a Compression Ignition Optical Engine for Different Tangential Port Opening Areas

“…Their study also focused only on the compression stroke, where the eccentricity of the swirl center also caused in-cylinder flow to be asymmetric, which lowered the swirl ratio. In our previous studies, we measured the flow velocity inside cylinders when changing the engine speed and the opening area of helical ports under both the motored-and the fired-engine conditions [14,15,34,35]. We found that by changing the helical port's opening areas, SCPs do not shift significantly, and airflow velocities do not change with an increase in engine speed.…”

“…However, since these methods measure only one point in a flow field, it is difficult to measure flow velocities in the entire engine cylinder. Therefore, the particle image velocimetry (PIV) technique has garnered attention in terms of measuring flow velocities simultaneously at multiple points inside the engine cylinders without interfering with the flow fields [12,[24][25][26][27][28][29][30][31][32][33][34][35][36][37]. In [30], the PIV technique was applied during the compression stroke to a light-duty optical diesel engine.…”