AbstractThe compression‐ignition properties of crude Jatropha and camphor oil blends with di ethyl ether (DEE) added is covered in this research. Six fuel samples are made based on volume: 90% C70J30 with 10% diethyl ether (C70J30 + 10% DEE), 90% C30J70 with 10% di‐ethyl ether (C50J50 + 10% DEE), 70% Camphor oil with 30% crude Jatropha oil (C70J30), 50% Camphor oil with 50% crude Jatropha oil (C50J50), 30% Camphor oil with 70% crude Jatropha oil (C30750). A four‐stroke, one‐cylinder, naturally aspirated, compression‐ignition engine operating at a constant 1500 rpm with a load range of 0%–100% with a 25% interval is used for the experiment. According to test findings, the C70J30 + 10% DEE has the lowest brake‐specific energy consumption of 11.68 kJ/kWh, the maximum energy efficiency of 62.56%, and the highest thermal efficiency of 30.81%. Compared to the other biofuels examined, this puts it more in line with diesel. Additionally, blends of crude Jatropha oil and camphor oil showed at least 4.46 g/kWh of CO, 0.259 g/kWh of HC, and 74% of smoke opacity when DEE was added. However, it raises CO2 to 0.792 kg/kWh and NO to 9.54 g/kWh. The greatest peak pressure and quickest heat release are produced by adding more DEE as a fuel additive and using a larger percentage of camphor oil. It also increases the coefficient of variation of the peak pressure throughout 100 cycles. All things considered, the C70J30 + 10% DEE's CI engine features are better.