Nonrenewable fossil fuels are in higher demand, and with fossil fuels rapidly reducing, alternative fuels seem to be in higher demand as well. Blended fossil fuels and biofuels are unlike anything else on the market. The Taguchi method was used to analyze the optimal combination of compression ratio & ethanol blend percentage at a fixed speed in this experimental investigation. Since maximum engine efficiency is desirable, the output parameter considered in this study was Brake Thermal Efficiency (BTE). Maximum CO<inf>2</inf> emission indicates a decrease in HC and CO, so carbon dioxide (CO<inf>2</inf>) and nitrogen oxides were regarded as emission production responses. The current experiment was conducted at 1550 rpm in a single cylinder 4 stroke VCR CI engine with 17.1, 18.1, and 19.1 CR with 30, 10, and 20 Jojoba oil biodiesel-diesel blends. The parameters contributions are examined by three-dimensional surface plot and ANOVA. The experimental output shows that at 20CE and B20 brake thermal efficiency of the engine was higher due to the best fuel combustion. Blend kind was the affecting factor for the higher carbon dioxide emission, because of the higher O molecules in biodiesel. The effect of compression ratio was more in the manufacturing of nitrogen oxides. For low CR, nitrogen oxides are lower. © 2023 Elsevier B.V., All rights reserved.