Transient engine operation of direct-injection spark ignition engines can result in high particulate number emissions. To investigate the causes of soot formation, an engine test rig was developed to perform detailed measurements of real transient operation. For this purpose, a single-cylinder full-metal engine with a real combustion chamber geometry was equipped with minimally invasive optical accesses. Simultaneous high-speed endoscopic PIV, spray visualization, and combustion imaging were applied to investigate the in-cylinder processes in detail. Endoscopic PIV was first compared in the central symmetry plane with classical PIV performed at the equivalent optical engine at steady-state operation for verification. Then the engine parameters of a tip-in performed by the corresponding four-cylinder engine, which led to high particle number emissions, were applied to the single-cylinder engine. The engine parameters were in a good agreement and particle number emissions due to the maneuver were within the same range of several 10⁶ #/cm³. In total, 19 repetitions of the tip-in maneuver were analyzed with respect to the in-cylinder processes and repeatability of engine parameters. Furthermore, the in-cylinder flow field during the late compression stroke, flame propagation, and soot luminosity of single cycles during the tip-in indicated cause-and-effect chains for the formation of pool fire and soot at the injector tip. The direction of the flow below the spark plug influenced the direction of flame propagation. An early arrival of the flame enhanced the formation of soot from fuel films formed on the piston surface or at the injector. In engine applications, counter measures can be applied to reduce the particle number emissions when accounting for these indicated cause-and-effect chains.

直喷式火花点火发动机的瞬态发动机操作会导致高颗粒物排放。为了调查烟灰形成的原因，开发了一种发动机试验台，以对真实的瞬态运行进行详细的测量。为此，具有真实燃烧室几何形状的单缸全金属发动机配备了微创光学通道。同时使用高速内窥镜PIV，喷雾可视化和燃烧成像技术来详细研究缸内过程。首先将内窥镜PIV在中央对称平面上与在稳态操作下在等效光学引擎上执行的经典PIV进行比较，以进行验证。然后由相应的四缸发动机执行加速踏板的发动机参数，导致高颗粒物排放的技术被应用于单缸发动机。发动机参数非常吻合，并且由于该操纵而产生的微粒数排放在几十个相同的范围内⁶＃/ cm ³。总体上，针对缸内过程和发动机参数的可重复性，分析了19个重复的踩油门动作。此外，在后期压缩冲程期间的缸内流场，火焰传播以及在踩入期间的单个循环的烟灰发光度指示了在喷射器尖端形成池火和烟灰的因果链。火花塞下方的流动方向影响了火焰传播的方向。火焰的早期到达增强了由在活塞表面或喷射器上形成的燃料膜形成的烟灰。在发动机应用中，考虑到这些指示的因果链时，可以采取对策来减少颗粒物的排放。