The improvement of engine efficiency, without adversely affecting oil consumption, blowby-gas, wear, or costs are desirable objectives for today's engine manufacturers as they strive to improve engine performance while trying to meet increasingly stringent emissions regulations.
In this context the development of piston ring designs as well as optimized surface texturing and lubricating oil formulation is of main interest.
The combination of simulation programs and the application of dynamic online oil emission measurement techniques lead to a target oriented development and a deeper understanding of the mechanisms causing oil consumption. The paper presents the results of the experimental and theoretical investigations of oil consumption mechanisms. A mass spectrometric method developed by the author et al., was used to measure the online oil emission in the exhaust gas by means of direct analysis of the lubricating oil molecules.
Running-in tests were conducted with a four-cylinder gasoline engine to observe the changing tribological performance due to variations in cylinder surface topography and piston ring geometry. In this context the results of the oil emission of a conventional honed surface in comparison with an optimised structure is discussed. Dynamic engine operation, as well as complete engine oil emission maps over different steady state conditions were evaluated.
