Study on the performance and emissions of compression ignition engine powered by diesel and biodiesel blends

This research tested all specifications of synthesized biodiesel according to the American Society for Testing and Materials (ASTM). The spirulina micro-algae synthesized biodiesel is mixed with conventional diesel in different blends named B0, B10, B20, and B30. The number after the letter “B” indicates the ratio of (biodiesel/diesel blend), which will be used instead of net diesel for experimental purposes. Those blend specifications are investigated, and results are tabled. The variable compression ratio, single-cylinder, water-cooled, and compression ignition engine, were utilized to study the effect of algae biodiesel/diesel blends on engine performance and its exhaust emission constituents. No hardware modification was required, and the blends directly injected in the combustion chambers. The experimental investigation showed that B10 with 14.5 CR and 25 % load -as compared with net diesel- enhances almost all performance parameters more than other blends (1.7 % more brake efficiency, 12.7 % less brake specific fuel consumption, 3.45 % less in exhaust temperature, 6.7 % more in A/F ratio, and volumetric efficiency was nearly the same). It also enhances some emission parameters more than other blends (12 % less in unburned hydrocarbons (UHC′s) emissions), but with a slight increase in nitric oxides (NO_X) emissions (2.4 % more than net diesel) with nearly the same values of carbon dioxide (CO₂) and carbon monoxide (CO) emissions. In general, in comparison with net diesel and with icreasing blend ratio, the following results are observed: the volumetric efficiency results fluctuated with a slight difference. Both brake thermal efficiency, air/fuel ratio, and exhaust temperature were enhanced with a slight increase in brake-specific fuel consumption. For emissions: The carbon dioxide and nitrogen oxides emissions both are reduced significantly, while there was a slight increase in CO and UHC′s levels. Finally, this work recommends using the algae biodiesel as clean and substitution fuel.