In this study, a series of cerium dioxide catalysts with varying hydrothermal temperatures and times were synthesized using the hydrothermal method, without the use of templates. The impact of varying hydrothermal conditions on the activity of cerium dioxide catalysts was investigated through experiments to examine their oxidation characteristics in soot combustion. Among the conditions tested, the hydrothermal conditions of 140 °C and 6 h yielded the most optimal catalytic oxidation of soot, with a combustion characteristic temperature (T_p) of 552 °C and a reduction of 122.9 °C. The integrated combustion index (S) and combustion stability coefficient (R_w) were found to be 27.97 × 10⁸ %²min⁻²°C⁻³ and 90.76 × 10⁵, respectively. The indices of S and R_w exhibited an improvement of 51.1% and 36.93%, respectively.

The problem of removing NO_x and carbon particle emissions from diesel engines has been a challenge in the field of environmental protection, which is prompting people to actively explore ways to improve the efficiency of pollutant emission treatment. Due to the high price of precious metals, developing an alternative catalytic material with high catalytic activity and stability is a difficult task. Perovskite, with its stable and flexibly variable crystal structure, has become a research hotspot in the field of catalysis. This paper discusses the structure of perovskite catalysts and the mechanism behind the simultaneous catalytic oxidation of diesel engine soot and NO_x. Meanwhile, it provides a comprehensive review of the preparation methods and A/B site modification strategies, establishing a foundation for the synthesis and A/B site modification of perovskite catalysts capable of catalyzing the oxidation of soot and NO_x simultaneously. Additionally, this article offers an outlook on the challenges and future development of perovskite catalysts in this field.

In order to solve the problem of combustion cycle variation in two-stroke aviation kerosene piston engines under idle conditions, experiments were conducted to investigate the influence of intake air temperature on combustion cycle variation and output work. The coefficient of variation of the indicated mean effective pressure was used to characterize combustion cycle variation. The results showed that there is a negative correlation between the engine combustion work and the combustion cycle variation. In the lower range, increasing the intake air temperature has a greater effect on reducing the combustion cycle variation, while in the higher range, the combustion cycle variation has a greater impact on the output work. At the same time, the influence of intake air temperature on the fuel evaporation rate is related to engine speed, and this relationship weakens as the engine speed increases. In the range of 0~40 °C, the higher the intake air temperature, the larger the stable combustion range.