Crank angle resolved floating-liner friction measurements on microstructured cylinder liner surfaces
The improvement of efficiencies is a major objective in the development of modern concepts for internal combustion engines. The mechanical efficiency, besides the thermodynamic efficiency, contributes considerably to fuel consumption and exhaust emissions. The piston group, consisting of the piston, the piston rings, the lubricant and the cylinder liner has, depending on the engine type and operation point, the highest proportion of the mechanical losses. The tribology of the piston group, however, depends regarding the piston stroke and the working cycle on varying boundary conditions.
This paper focuses on this aspect by using locally microstructured cylinder liner surfaces. Moreover, a new developed Floating-Liner Measurement System for crank angle resolved piston friction force measurements is presented, being applied to a heavy duty research engine. The experimental results show, that by applying microstructures in the TDC and BDC of the liner, a substantial reduction of friction force peaks by up to 78% can be achieved. A significant dependency of the achievable reduction has been found from the microstructure density per area.
KeywordsFriction Force Piston Ring Cylinder Liner Dead Centre Frictional Loss
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