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In terms of international efforts for conservation of resources and reducing CO2-emission, the thermal efficiency of SI engines needs to be increased. One key enabler to achieve this goal is the availability of highly knock-resistant fuels: it allows to break up the trade-off between elevated compression ratio demanded for high part-load efficiency and a reduced knock tendency at high engine loads by a minimized requirement for adverse spark retard. In view of the world’s fuel map, which is dominated nowadays by qualities between 91 and 98 RON, there is a beginning transition towards increased knock resistance (above 100 RON) being observed in several countries. The corresponding standards for engine-based fuel quality rating provide a RON scale covering the range from 40 to 120.3, which basically seems to be enough. At a second glance the change in reference material from isooctane/n-heptane mixtures towards isooctane with TEL for RON > 100 changes the rating behavior of the method.

This report describes the monitoring of bimetal aluminum/ steel bearings by means of the vibration analysis method, in particular for purposes of detection of fatigue failures in the bearing contact layer. A built-in measurement system is used on a plain bearing test rig, continuously analyzing machine vibrations at the bearing locations and comparing them to a reference state. This practice is based on the principle that a change in the surface characteristics of a hydrodynamic bearing also causes change in the spring and damping characteristics of the vibration absorbing elements. Thus, from the changes in the vibration transfer characteristics of the bearing, the condition of the bearing surface can be indirectly assessed. The fundamental principles of plain bearing vibration transfer behavior, the mathematics of the monitoring system, and the application of the system to a test rig are described in detail. The results demonstrate the successful application of the system.

A modified equation for the heat transfer coefficient has been established, because the original equation proposed by the author in 1967 provides at low load and motored operation to low results. The reason for this descrepancy seems to be a steady state soot layer, the thickness of which increases with increasing load, where as it does not exist in a motored engine. All equations for the heat transfer coefficient known either to, do not represent the real heat transfer coefficient accuring at the soot layer surface, but include the thermal conductivity resistance of the soot layer. The real heat transfer coefficient is more than two times higher than assumed up to now. These results also show the adiabatic engine in a totally new light.