Optical study on the spray and combustion of diesel cyclopentanol blend fuels on a constant volume chamber

Among the biofuels produced from lignocelluloses, cyclopentanol is a promising candidate. In this study, a constant volume chamber (CVC) is employed to investigate the effects of adding cyclopentanol in diesel with different proportions (0%, 10%, and 20% in volume) on the spray and combustion characteristics. Tests are performed under three injection pressures (100, 120 and 140 MPa). The experimental results in the CVC show that the atomization characteristics of cyclopentanol-diesel blends are better in the early stage of spray and slightly worse in the later stage than those of diesel. As the injection pressure increases, the diesel cyclopentanol blend fuels improve the air fuel mixing. The addition of cyclopentanol has risen the temperature of the flames and cut the soot formation of diesel by 12.7-89.2% under all injection pressure conditions. The addition of cyclopentanol is found to reduce the natural flame luminosity and combustion duration significantly due to the effective combustion process acceleration and is helpful for improving the combustion, especially for CP10. Overall, blending cyclopentanol into diesel has a great soot reduction potential with a low cetane number and improved mixing, and CP10 can be seen as a future alternative fuel, especially under an injection pressure of 140 MPa.