Hruby Sarah L, Chrysafis Pavlos, Kusar Henrik, Pach Mayte, Hittig Henrik
Department of Chemical Engineering, KTH Royal Institute of Technology, Brinellvägen 8, Stockholm 114 28, Sweden.
Scania Technical Centre, Scania CV AB, Granparksvägen 10, Södertälje 151 48, Sweden.
ACS Omega. 2025 Jun 4;10(23):24235-24251. doi: 10.1021/acsomega.4c11346. eCollection 2025 Jun 17.
The formation of internal diesel injector deposits (IDIDs) in heavy-duty engines is a growing problem as engine technology becomes more advanced while fuel blends become more diverse, posing new challenges for mixing and compatibility. IDIDs have a variety of causes that can be challenging to pinpoint due to the number of factors involved, such as engine operation effects, fuel types, fuel additives, and fuel contamination. The aims of this study were to characterize IDIDs formed in an injector from an engine operating on a biofuel blend contaminated with coolant, gain a deeper understanding of the underlying formation mechanisms, and identify potential markers of coolant contamination in failed field injectors. In this study, a failed injector from the field was examined that was known to have fuel contamination from coolant. Laboratory experiments using the thermal deposit test (TDT) were carried out to generate deposits from a test fuel spiked with coolant. The laboratory and field deposits were characterized and compared using scanning electron microscopy with energy-dispersive X-ray spectroscopy (SEM-EDX), Fourier transform infrared attenuated reflectance spectroscopy (FTIR-ATR), and pyrolysis combined with gas chromatography (Py GC-MS). The results indicate that the deposits generated in the TDT were found to be primarily composed of sodium carboxylates originating from the organic acid technology additives in the coolant. The deposits were found to have structures with similarities to grease soaps, oleogels, or paraffin wax, suggesting that similar formation mechanisms may be involved. In contrast, the field injector deposits consisted of three distinct types: a cracked layer composed of sulfate salts and metal carboxylates, a globular cluster layer consisting of metal carboxylates, and particulate deposits that differ from the surroundings. The high proportion of sodium carboxylates in the globular cluster deposits was the key similarity to the laboratory deposits. In addition to the high sodium content, particulate deposits containing silicon and aluminum or aluminum and nitrogen were identified as potential markers of coolant contamination in IDIDs.
随着发动机技术日益先进，而燃料混合物愈发多样，重型发动机中内部柴油喷射器沉积物（IDIDs）的形成问题日益凸显，给混合与兼容性带来了新挑战。IDIDs成因多样，由于涉及发动机运行影响、燃料类型、燃料添加剂及燃料污染等诸多因素，难以精确查明。本研究旨在表征因使用受冷却液污染的生物燃料混合物运行的发动机喷射器中形成的IDIDs，深入了解其潜在形成机制，并识别出现故障的现场喷射器中冷却液污染的潜在标志物。在本研究中，对一个已知受冷却液燃料污染的现场故障喷射器进行了检查。利用热沉积试验（TDT）开展实验室实验，从添加了冷却液的测试燃料中生成沉积物。使用扫描电子显微镜结合能量色散X射线光谱仪（SEM - EDX）、傅里叶变换红外衰减全反射光谱仪（FTIR - ATR）以及热解结合气相色谱法（Py GC - MS）对实验室沉积物和现场沉积物进行表征与比较。结果表明，TDT中生成的沉积物主要由源自冷却液中有机酸盐技术添加剂的羧酸钠组成。发现这些沉积物具有与润滑脂皂、油凝胶或石蜡相似的结构，表明可能涉及类似的形成机制。相比之下，现场喷射器沉积物由三种不同类型组成：由硫酸盐和金属羧酸盐构成的裂纹层、由金属羧酸盐组成的球状聚集体层以及与周围环境不同的颗粒沉积物。球状聚集体沉积物中羧酸钠的高比例是与实验室沉积物的关键相似之处。除了高钠含量外，含有硅和铝或铝和氮的颗粒沉积物被确定为IDIDs中冷却液污染的潜在标志物。
