The present experimental study was aimed to investigate the combined effect of external mixture formation and cooled exhaust gas recirculation (EGR) on performance and emissions characteristics of partially homogeneous charge compression ignition (PCCI) engine. A conventional single‐cylinder four‐stroke compression ignition engine was modified to operate on PCCI mode with the supply of diesel fuel vapor via intake manifold during suction stroke. A Homogenous air‐fuel charge was produced by using a retrofit system to provide fuel vapor. The engine was operated in two modes, direct injection (DI)‐EGR and PCCI (DI‐fuel vapor‐EGR) mode, and then results were compared with DI (conventional) mode. Constant 10% EGR was maintained during DI‐EGR and PCCI modes. Compared to conventional mode, in PCCI mode at full engine load, NO_x and smoke opacity were decreased by 2.39 g kW⁻¹ hr⁻¹ and 27% respectively, and the marginal penalty in HC and CO emissions by 0.4 and 0.1 g kW⁻¹ hr⁻¹ was observed. Brake thermal efficiency was slightly reduced by 2.5% compared to DI mode.

中文翻译：

---

外部混合气形成和冷却的废气再循环对部分预混合增压压燃式发动机的性能和排放特性的综合影响

本实验研究旨在研究外部混合物形成和冷却的废气再循环（EGR）对部分均质充量压燃（PCCI）发动机的性能和排放特性的综合影响。对传统的单缸四冲程压缩点火发动机进行了修改，使其在PCCI模式下运行，并在进气冲程期间通过进气歧管供应柴油蒸汽。通过使用改装系统提供燃油蒸气，产生了均质的空气燃料。发动机以两种模式运行：直接喷射（DI）-EGR和PCCI（DI-燃料蒸气-EGR）模式，然后将结果与DI（常规）模式进行比较。在DI‐EGR和PCCI模式下，EGR保持恒定的10％。与常规模式相比，在PCCI模式下，发动机全负荷运行时，NO _x和烟的不透明度分别降低了2.39 g kW ^-1  hr ^-1和27％，并且观察到HC和CO排放的边际损失分别为0.4和0.1 g kW ^-1  hr ^-1。与DI模式相比，制动热效率略微降低了2.5％。