Enhancing the Geometrical Performance Using Initially Conical Cylinder Liner in Internal Combustion Engines—A Numerical Study

Abstract

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.

A Review of Energy Loss Reduction Technologies for Internal Combustion Engines to Improve Brake Thermal Efficiency

“…Improvement of the PRL conformation is expected to reduce the friction and the oil losses, limited by the deformations under higher temperature gradients, thermal stresses, and mechanical loads under fired operations. Alshwawra et al [45] proposed a methodology to achieve better PRL conformation and engine friction reduction via the enhancement of the liner's straightness, roundness, and parallelism during the fired operation state, using a conical-shaped liner with elliptical cross-sections. Moreover, diamond-like carbon (DLC) coatings applied to aluminum alloy pistons are beneficial for achieving low friction, high wear resistance, and strong corrosion resistance.…”

Structural Performance of Additively Manufactured Cylinder Liner—A Numerical Study

“…Alshwawra et al [14] showed through advanced simulation techniques that starting the engine with an elliptical liner can reduce the roundness error significantly in the hot state. Further enhancement in the liner's geometrical performance can be achieved with a superposition of this elliptical shape with a conical liner form in the cold state [15]. Flores [13] presented a methodology to control the liner deformation and to enhance its geometrical performance through advanced honing techniques.…”

Experimental investigation of the effect of tribological performance of reduced graphene oxide additive added into engine oil on gasoline engine wear

“…The surface is well polished to eliminate the effect of roughness of honing marks as liner is produced conical and elliptical in its cold state. 13 Figure 7 presents optical digital image of non-tested ball. Table 2 shows chemical composition of the non-tested ball, which is low alloy martensitic chrome steel, AISI 52100 steel ball (100 Cr6).…”

“…Figure 5.Figure6presents polished surface of plateau honing marks after cutting process. The surface is well polished to eliminate the effect of roughness of honing marks as liner is produced conical and elliptical in its cold state 13. Figure7presents optical digital image of non-tested ball.…”