Reducing friction is an important aspect to increase the efficiency of internal combustion engines (ICE). The majority of frictional losses in engines are related to both the piston skirt and piston ring–cylinder liner (PRCL) arrangement. We studied the enhancement of the conformation of the PRCL arrangement based on the assumption that a suitable conical liner in its cold state may deform into a liner with nearly straight parallel walls in the fired state due to the impact of mechanical and thermal stresses. Combining the initially conical shape with a noncircular cross section will bring the liner even closer to the perfect cylindrical shape in the fired state. Hence, a significant friction reduction can be expected. For the investigation, the numerical method was first developed to simulate the liner deformation with advanced finite element methods. This was validated with given experimental data of the deformation for a gasoline engine in its fired state. In the next step, initially conically and/or elliptically shaped liners were investigated for their deformation between the cold and fired state. It was found that, for liners being both conical and elliptical in their cold state, a significant increase of straightness, parallelism, and roundness was reached in the fired state. The combined elliptical-conical liner led to a reduced straightness error by more than 50% compared to the cylindrical liner. The parallelism error was reduced by 60% to 70% and the roundness error was reduced between 70% and 80% at different liner positions. These numerical results show interesting potential for the friction reduction in the piston-liner arrangement within internal combustion engines.

中文翻译：

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在内燃机中使用最初的圆锥形气缸套提高几何性能的数值研究

减少摩擦是提高内燃机（ICE）效率的重要方面。发动机中的大多数摩擦损失与活塞裙和活塞环-缸套（PRCL）布置有关。我们基于以下假设研究了PRCL排列构象的增强：合适的圆锥形衬套在冷态下可能会由于机械应力和热应力的影响而变形为在燃烧状态下具有几乎笔直的平行壁的衬套。将最初的圆锥形与非圆形横截面结合在一起，可使内衬在烧结状态下更接近理想的圆柱形状。因此，可以期望显着降低摩擦。为了调查 首先开发了数值方法，以使用高级有限元方法模拟衬砌变形。给出的汽油发动机变形状态的实验数据对此进行了验证。在下一步中，首先研究锥形和/或椭圆形的衬套在冷态和烧结态之间的变形。已经发现，对于在冷态下既是圆锥形又是椭圆形的衬里，在烧成状态下直线度，平行度和圆度显着增加。与圆柱形衬套相比，组合的椭圆形锥形衬套导致直线度误差降低了50％以上。在不同衬板位置，平行度误差降低了60％至70％，圆度误差降低了70％至80％。