The main objective of this work was to evaluate the potential of ozone to overcome the low load limitations of Direct-Injection Gasoline Compression Ignition (D-I GCI) engines. Experiments were performed in a single-cylinder diesel engine fuelled with directly-injected 95 RON gasoline at 2 bar IMEP. Engine speed was set to 1500 rpm. Intake pressure was set to 1 bar in order to investigate typical low load operating conditions. Chemical computation revealed that the O atoms coming from the O₃ molecules and responsible for promoting fuel autoignition exhibited a maximum concentration near 30° before TDC. Experiments showed that a narrow umbrella angle extends the early injections range up to -60 CAD, better matching with ozone decomposition. Injection timing can be employed to better exploit the oxidizing effect of ozone, which proved to be dependent on local conditions of temperature, equivalence ratio, and concentration of O atoms and of the residual NO trapped after each combustion cycle. Results showed that the impact of ozone is generally higher at early injection, but that interaction between O₃ molecules and NO contained in the trapped gas can drastically reduce or even make the promoting effect of ozone ineffective. Finally, seeding the intake of the engine with ozone is shown to be an effective way to improve the autoignition propensity of high octane fuel and to overcome the low load limitation of D-I GCI engines.

这项工作的主要目的是评估臭氧克服直喷式汽油压缩点火（DI GCI）发动机的低负荷限制的潜力。实验是在2 bar IMEP的直接喷射95 RON汽油作为燃料的单缸柴油发动机上进行的。发动机转速设置为1500 rpm。进气压力设置为1 bar，以研究典型的低负荷运行条件。化学计算表明，O原子来自O ₃在TDC之前，负责促进燃料自燃的分子在30°附近表现出最大浓度。实验表明，较窄的伞角可将早期进样范围扩大至-60 CAD，与臭氧分解效果更好。可以采用喷射定时来更好地利用臭氧的氧化作用，事实证明，该氧化作用取决于温度，当量比，O原子的浓度以及每个燃烧循环后捕获的残留NO的局部条件。结果表明，臭氧的影响通常在早期注入时较高，但O ₃之间的相互作用被捕集的气体中所含的分子和一氧化氮会大大降低甚至使臭氧的促进作用失效。最后，用臭氧对发动机进气口进行播种被证明是提高高辛烷值燃料自燃倾向并克服DI GCI发动机低负荷限制的有效方法。