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.

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This paper focuses on process chains for power train components of passenger cars and heavy duty vehicles. In the project “Powertrain 2025” particular attention is being paid to increase the resource efficiency of the manufacturing process chains and reduce energy demand during service life. In detail cylinder liners are equipped with an adapted geometry and topography which reduces friction losses. Process chains for chassis components are investigated and optimized in order to increase the resource efficiency during manufacturing, service life and maintenance. In addition, process chains for the manufacturing of drive shafts are adjusted. By eliminating hard machining, energy is saved and friction losses are reduced by laser machining of microstructures. Furthermore, micro dimples are applied in vane pumps, which leads to a tribological improvement and thus enhances their friction behaviour. Moreover, a system architecture for process planning is developed and ecologically optimized process parameters are calculated. For a final consideration, a calculation software is developed which enables to calculate the main energy consumption of the manufacturing processes and the carbon footprint for the expected service life. A weight reduction of the powertrain components of 4.5 kg per vehicle and a potential annual energy saving of 13,073 MWh is obtained.