Turbulent jet ignition (TJI) is a promising strategy to ignite diluted air-fuel mixtures; this is usually generated by igniting a fraction of the mixture inside a small pre-chamber. Nevertheless, the processes that take place inside the pre-chamber, as well as the injection of the turbulent jet into the main chamber and its subsequent re-ignition are not fully understood. The current work presents an experimental investigation that studies the effects of the nozzle size, turbulence level, and air-fuel mixture on the pre-chamber ignition and main chamber re-ignition and combustion. To accomplish this, a series of experiments have been carried out under different boundary conditions. To understand the phenomena taking place in the pre- and main chamber, two different approaches were taken: On one hand, (1) pressure-based diagnostics were applied by fitting a pressure sensor in each of the chambers. This was done to trace the pressure evolution during the whole combustion event and to calculate the heat-release. On the other hand, (2) optical diagnostics were setup on both combustion chambers, using dual schlieren setups synchronized at the same frame rate.

The optically accessible test rig and the combination of schlieren in the pre-chamber (PC) & main-chamber (MC) allows to visualize the ignition, flame propagation, quenching mechanisms and re-ignition under a wide range of boundary conditions. This combined with the pressure traces and heat-release give a full understanding of the ignition and combustion processes. Higher turbulence levels and equivalence ratios increase the propagation of the flame front and the peak pressure in the pre-chamber. The resulting higher nozzle-exit velocities lead, on one hand, to faster mixing and therefore to a larger portion of main chamber fuel within the jet, which decrease the main chamber combustion duration. On the other hand, to high quenching and longer re-ignition times, which show the adverse effect.

湍流喷射点火（TJI）是一种点燃稀薄空气燃料混合物的有前途的策略。这通常是通过在小型预燃室内点燃一小部分混合物而产生的。然而，尚未完全了解发生在预燃室内部的过程以及将湍流射流注入主燃烧室并随后重新点燃的过程。目前的工作是一项实验研究，研究喷嘴尺寸，湍流度和空气-燃料混合物对预燃室点火以及主室再燃和燃烧的影响。为此，在不同的边界条件下进行了一系列实验。为了了解在前室和主室中发生的现象，我们采取了两种不同的方法：一方面，（1）通过在每个腔室中安装压力传感器来进行基于压力的诊断。这样做是为了追踪整个燃烧过程中的压力变化并计算热量释放。另一方面，（2）在两个燃烧室上都设置了光学诊断程序，使用了以相同帧速率同步的双schlieren设置。

光学可访问的测试装置以及预燃室（PC）和主燃室（MC）中的schlieren的组合，可以在各种边界条件下可视化点火，火焰传播，淬火机理和重新点火。结合压力迹线和热量释放，可以全面了解点火和燃烧过程。较高的湍流度和当量比会增加火焰前锋的传播和预燃室中的峰值压力。一方面，所得到的较高的喷嘴出口速度导致更快的混合，并因此导致射流内的主室燃料的更大部分，这缩短了主室的燃烧持续时间。另一方面，高淬火和更长的重燃时间，显示出不利的影响。