Experimental investigations and simulations on cam-roller-friction

Abstract

Despite the increase in alternative drive solutions for passenger cars, such as plug-in hybrid vehicles or fully electric vehicles, the internal combustion engine will retain its supremacy as the main drive in the next 10 to 15 years. [1] This fact, coupled with the ever-increasing demands of the customers and legislators, especially in regard to fuel consumption and emissions, pushes the thermodynamic and mechanical improvement of the internal combustion engine into the foreground of all engine development projects at the Daimler AG. [2]

On the side of the engine mechanics efficiency improvements are mainly achieved by the reduction of frictional losses. Figure 1 shows the frictional losses of a dragged engine at an engine speed of 2000 rpm and 90°C oil and water temperature. It can be seen that at these operating speeds the friction in the crank train (compromised of the piston assembly and crankshaft) dominates.