Effect of injection timing on particle size distribution of a diesel engine fueled with biodiesel-diesel blends

¹ Department of Mechanical and Automotive Engineering Technology (MAet), Faculty of Engineering and Technology, King Mongkut’s University of Technology North Bangkok (Rayong Campus), Nonglalok, Bankhai, Rayong 21120, Thailand.
² Research Centre for Combustion Technology and Alternative Energy (CTAE), Science and Technology Research Institute, King Mongkut’s University of Technology North Bangkok, Bangkok 10800, Thailand.

^* Corresponding author: pomprab.s@eat.kmutnb.ac.th

Abstract

The purpose of this study is to investigate injection timing affected particle size distribution of a diesel engine fueled with biodiesel/diesel blends. The biodiesel blending ratios include 7, 10 and 20%vol. The experiments were operated at engine speed 1,500 rpm under 25, 50 and 75% engine loads and two different injection timing (25.5 CAD BTDC and 27.5 CAD BTDC). The effects of biodiesel addition and injection timing on the changes in black smoke and particle size distribution were discussed. Results showed that the standard injection timing for the addition of biodiesel, especially for 20% biodiesel blended with diesel fuel (B20) had a significant effect of increasing particle concentration and thus black smoke emission. The advanced injection timing for B20 could improve combustion efficiency and reduce small particles emission in nucleation-mode (Dp 5 – 50 nm) and particles in accumulation-mode (Dp 50 – 1,000 nm) became the smaller particle size, compared to standard and retarded injection timing. Moreover, the oxygen content in biodiesel could improve combustion efficiency and reduce the emission but it is necessary to modify the engine especially fuel injection timing.