Effect of n-pentanol additive on compression-ignition engine performance and particulate emission laws

•The PM emissions were studied under the condition of EGR, load and blend fuels.•The influence of the additive n-pentanol in biodiesel/diesel blends was analyzed.•The combination of n-pentanol and EGR reduced TPMC-NOX emissions simultaneously.•Soot and TPNC emissions were decreased by n-pentanol addition.•The addition of n-pentanol could reduce the particle geometric mean diameter. Biodiesel has a high viscosity, which limits its application to engines. However, n-pentanol has low viscosity and high volatility, which is considered a promising additive. This study examined the influence of n-pentanol/biodiesel/diesel blends on the performance and particulate emissions of a diesel engine at different loads, under the condition of coupling exhaust gas recirculation (EGR) (0–30%). The three test fuels included pure diesel (D100); 80% diesel and 20% biodiesel blended fuel (BD20); 64% diesel, 16% biodiesel, and 20% n-pentanol blended fuel (BDP20). The results indicated that the influence of EGR on the NOx emissions between fuels was greater than that of the physicochemical properties of the fuels. For the same EGR rate, the heat release rate (HRR), peak in-cylinder pressure (IP), and brake thermal efficiency (BTE) increased with the engine load increased. After adding n-pentanol to BD20, the HRR increased. The peak IP and BTE values of BDP20 were similar to those of D100 and BD20. With the addition of n-pentanol, the total particulate number concentration (TPNC), soot, and total particulate mass concentration (TPMC) emissions decreased. Furthermore, the trade-off relationship between TPMC and NOx was improved, and the geometric mean diameter (GMD) of the particles decreased.