In this work, the Engine Combustion Network Spray G injector was mounted in the Darmstadt optical-accessible engine to study phenomena typical of multi-hole, early direct-injection events in spark-ignition engines characterized by tumble flow charge motion. Dedicated experimental measurements of both in-cylinder spray morphology and flow velocities before and after the injection process were carried out to assess the adopted numerical setup under real engine conditions. A dynamic secondary breakup model from the literature was coupled with an atomization multi-motion regime model. The model was validated against state-of-the-art ECN Spray G experiments for a constant-volume chamber under low evaporating condition. Then, the simulation of the spray injection in the engine was carried out and the achieved results were compared against the experimental data. Overall, good agreement between experiments and simulations was observed for the spray morphology and velocity fields in both cases. With reference to engine calculations the intake flow was seen to induce spray asymmetry. A partial vortex generated during the intake phase on the tumble plane interacts with the spray, developing into a full vortex which induces an upward flow that stabilizes the spray. The upward flows below the intake valve increase the dilution of the plume outside the tumble plane, which therefore exhibits reduced penetration. Moreover, the intake valves protect from the energetic intake flow the recirculation vortex generated at the tip of the plumes that lie outside the tumble plane. The intake flow helps fuse the vapor fuel clouds of the individual plumes near the injector tip, obtaining a vapor fuel with a shape like that generated by a horseshoe multi-hole injector. Finally, a phenomenological model of the interaction between the multi-hole injector jets and the engine intake flow was introduced to describe the spray evolution in a typical DISI engine.

在这项工作中，发动机燃烧网络喷射 G 喷射器安装在达姆施塔特光学可访问发动机中，以研究以滚流电荷运动为特征的火花点火发动机中多孔、早期直接喷射事件的典型现象。对喷射过程前后的缸内喷雾形态和流速进行了专门的实验测量，以评估在真实发动机条件下采用的数值设置。文献中的动态二次分解模型与雾化多运动状态模型相结合。该模型针对低蒸发条件下的恒容室的最先进的 ECN Spray G 实验进行了验证。然后，对发动机中的喷雾喷射进行了模拟，并将获得的结果与实验数据进行了比较。总体而言，在两种情况下，对于喷雾形态和速度场，观察到实验和模拟之间的良好一致性。参考发动机计算，进气流被视为引起喷雾不对称。在滚流平面进气阶段产生的部分涡流与喷雾相互作用，发展成一个完整的涡流，引起向上流动，稳定喷雾。进气门下方的向上流动增加了滚流平面外羽流的稀释，因此渗透率降低。此外，进气阀可防止高能进气流在位于滚流平面外的羽流尖端产生的再循环涡流。进气流有助于融合喷射器尖端附近单个羽流的蒸汽燃料云，获得形状类似于马蹄形多孔喷射器产生的形状的蒸汽燃料。最后，引入了多孔喷射器射流与发动机进气流之间相互作用的现象学模型来描述典型 DISI 发动机中的喷雾演变。