The effects of mixing pure vegetable oils with diesel fuels and using them in diesel engines were explored in this study. Due to its great production, Chorella protactes, a microalgae species, was employed as a vegetable oil. First, pure microalgae oil was combined with 5% (DSYK-5) and 10% (DSYK-10) diesel reference fuel (RDF) by volume for this experiment. The resulting blended fuels and diesel reference fuel were put to the test in a four-cylinder, four-stroke diesel engine at 1500 rpm and various loads. With the use of pure oil, the results showed a 4.64 percent rise in specific fuel consumption (SFC). CO emissions reduced by 9.05 percent on average when DSYK-5 fuel was used, while CO emissions increased when DSYK-10 fuel was used. HC emissions reduced by 4.6 percent on average when blended fuels were used, whereas NOx emissions increased by 3.13 percent on average. CO2 emissions were comparable to RDF fuel when DSYK-5 fuel was used. When comparing RDF fuel to DSYK-10 fuel, fewer CO2 emissions were found. Average gas temperatures, cumulative heat releases, and cylinder pressure values all reduced as the pure oil ratio in the mixture ratio increased.