Optical Diagnostics Investigation on the Effect of Fuel Injection Timing on Partially Premixed Combustion Stratification and Soot Formation in a Single-Cylinder Optical Compression Ignition Engine 2019-24-0028
The present work investigates the effect of fuel injection timing on combustion stratification and soot formation in an optically accessible, single cylinder light duty diesel engine. The engine operated under low load and low engine speed conditions, employing a single injection scheme. The conducted experiments considered three different injection timings, which promoted Partially Premixed Combustion (PPC) operation. The fuel quantity of the main injection was adjusted to maintain the same Indicated Mean Effective Pressure (IMEP) value among all cases considered. Findings were analysed via means of pressure trace and apparent heat transfer rate (AHTR) analyses, as well as a series of optical diagnostics techniques, namely flame natural luminosity, CH* and C2* chemiluminescence high-speed imaging, as well as planar Laser Induced Incandescence (pLII). For the chemiluminescence high-speed imaging a novel methodology was developed to acquire the net spatially resolved chemiluminescence signal, using combustion spectroscopy to remove the background chemiluminescence and thermal radiation signal. The analysis suggests that when the injection timing advanced, the stratification of the combustion became weaker, as indicated by the natural luminosity signal, due to the better pre-mixing between the injected fuel and the surrounding air. The enhanced premixing resulted in lower levels of in-cylinder soot late in the combustion cycle and, presumably the lowest engine-out soot emissions, because of the limited formation of locally fuel-rich areas inside the cylinder. This came at the price of increased fuel consumption.
Citation: Touloupis, D., Vourliotakis, G., Keramiotis, C., Ramaswamy, K. et al., "Optical Diagnostics Investigation on the Effect of Fuel Injection Timing on Partially Premixed Combustion Stratification and Soot Formation in a Single-Cylinder Optical Compression Ignition Engine," SAE Int. J. Adv. & Curr. Prac. in Mobility 2(2):503-511, 2020, https://doi.org/10.4271/2019-24-0028. Download Citation
Author(s):
Dimitrios P. Touloupis, George Vourliotakis, Christos Keramiotis, Kumara Gurubaran Ramaswamy, Yannis Hardalupas, Alexander Taylor
Affiliated:
Imperial College London
Pages: 9
Event:
14th International Conference on Engines & Vehicles
ISSN:
2641-9637
e-ISSN:
2641-9645
Also in:
SAE International Journal of Advances and Current Practices in Mobility-V129-99EJ
Related Topics:
Diesel / compression ignition engines
Combustion and combustion processes
Fuel injection
Heat transfer
Fuel consumption
Engines
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