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近年来,燃油消耗率一直在稳定地下降,此外,还可通过改变燃烧过程以提高燃烧压力进而进一步降低油耗。这样,活塞的机械负荷和热负荷便会随之提高,即高于早先采用的钢一铝活塞所能承受的负荷。为此,设计了一种新型活塞,它由球铁下部和钢制上部组合而成,它能安全地承受所要求的高负荷。本文中详细地示出了大范围的三维有限元法计算结果。这些有限元计算结果全面地分析了这种新活塞机械负荷和热负荷的情况。其中也用图解表示了变形,尤其是活塞顶部、裙部和销座区域的变形情况。此外,还详细地图解描述了计算所得的温度和应力及其与测量值的对比。对于烧重油的柴油机,顶环槽温度是十分重要的。如果温度过低,便会产生硫酸。硫酸会导致严重的磨耗。借助专门设计措施来提高环槽温度,有可能有效地阻止硫酸的形成。这些设计措施的形成细节及作用,本文皆作了详细叙述,并经计算核实,与测量值相符。
In recent years, the fuel consumption rate has been steadily declining. In addition, fuel consumption can be further reduced by changing the combustion process to increase the combustion pressure. This increases the mechanical and thermal load on the piston, which is higher than the load on the earlier used steel-aluminum piston. For this purpose, a new type of piston was designed which consists of a combination of the lower part of the ductile iron and the upper part of the steel, which safely withstands the high loads required. The results of a large-scale three-dimensional finite element method are shown in detail in this paper. The results of these finite element analyzes fully analyze the mechanical and thermal loads of this new piston. The deformation is also illustrated graphically, in particular the deformation of the piston crown, skirt and pin holder area. In addition, the calculated temperature and stress are also graphically described in detail and compared with the measured values. For burned heavy oil diesel engines, the top ring groove temperature is very important. If the temperature is too low, it will produce sulfuric acid. Sulfuric acid can cause severe wear. With specially designed measures to increase the temperature of the sump, it is possible to effectively prevent the formation of sulfuric acid. The formation of these design measures details and role of this article are described in detail, and verified by calculation, in line with the measured value.