The hydrogen fueled internal combustion engine is an important technical route to promote the green and low-carbon transformation of the automotive industry and achieve the "dual carbon" strategic goal. However, during low-temperature cold start of a hydrogen engine, the water vapor generated by combustion can enter the crankcase and condense into water, causing oil emulsification and seriously affecting the reliability of the hydrogen engine. This study firstly proposed a rapid detection method for oil emulsification of the hydrogen engine. Then, the degrees of oil emulsification under driving conditions of medium and long distance at room temperature and of intermittent and short distance at low temperature, as well as the performance of the emulsified oil at different water contents were investigated. Finally, the effects of oil temperature and ventilation degree on oil emulsification were explored. The results show that the oil discharge weighing method can meet the need of hydrogen engine oil emulsification detection. Oil emulsification does not occur under the medium and long distance driving condition, but mainly occurs under the low-temperature, short and intermittent distance driving conditions. Although the water content of the emulsified oil reaches 25%, it still meets the lubrication need. It is also found that heating the engine oil to above 60℃ can effectively avoid the oil emulsification of the hydrogen engine. By heating the oil mixture to above 93℃, water can be quickly separated from the emulsion. Supplying fresh air at room temperature outside the engine body to enhance crankcase ventilation will accelerate the occurrence of oil emulsification.
| 科 Family | 属数 Number of genus | 种数 Number of species | 占总种数比例 Percentage of total species (%) | 属 Genus | 种数 Number of species | 占总种数比例 Percentage of total species (%) |
|---|---|---|---|---|---|---|
| 鹅膏菌科Amanitaceae | 2 | 11 | 5.26 | 鹅膏菌属 Amanita | 10 | 4.78 |
| 小菇科 Mycenaceae | 2 | 12 | 5.74 | 丝盖伞属 Inocybe | 5 | 2.39 |
| 多孔菌科 Polyporaceae | 8 | 14 | 6.70 | 蜡蘑属 Laccaria | 5 | 2.39 |
| 红菇科 Russulaceae | 3 | 23 | 11.00 | 小皮伞属 Marasmius | 6 | 2.87 |
| 小菇属 Mycena | 11 | 5.26 | ||||
| 光柄菇属 Pluteus | 5 | 2.39 | ||||
| 红菇属 Russula | 17 | 8.13 | ||||
| 栓菌属 Trametes | 5 | 2.39 |