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Conventional measuring systems are not able to measure the exactly valve timing on real engines. Due to their requirements, the measurement procedure and consequently their accuracy there are variances, which have a great influence on the measurement results. For an improvement of the gas exchange and finally the engine characteristics it is necessary to develop a new way to get the real valve timing on operating engines. Therefore the University of Applied Sciences Hannover developed a new measurement system to detect the exactly valve timing on real operating engines. This method uses the valve and the valve seat ring as an electrical switch, which is reached by an insulation of these parts against each other. The result is that the valve timing, the length of the opening time, valve overlapping and effects like valve bouncing are able to detect by this new measurement system.

The reliable function of the system piston - piston ring -liner depends strongly on the correct quantity of oil. A balance between the sufficient oil offer and minimum emission is to be found. For this system numerous computation programs exist however their results strongly depends from the boundary conditions. To assist in the understanding of this system it is to be used necessarily optical research methods. So that the lubricating film at the piston and at the piston rings can be examined, a cylinder of an engine had to be completely made of glass. The used glass must have the wetting characteristics of grey cast iron, so that the results are transferable. The used tracers to visualize the oil may not change the characteristics of the oil. Different photograph procedures were necessary, in order to identify the fundamental presence of oil and the bearing oil film. In this paper the test set-ups and results are described.

The function of the system valve stem - valve guide is dependent on the material combination and the available amount of oil. The wear on both components must be low at high running times to ensure a save function and keep the emission of the engine low. The knowledge about the friction- and wear mechanism is not obviously caused by missing information about the real amount of oil in the guide and over the oil transportation. This paper describes, in which way it is possible to visualize the valve behavior in a valve guide. Two test rigs with valve guides made out of glass are built up to investigate the behavior of the valve under running conditions. This research work realized for the first time, taking photographs of the oil distribution in a original scaled valve guide under running conditions.

Increasing efficiency of the high performance automobile engines results in higher temperatures in the valves, valve seat inserts and valve guides. This fact demands a higher heat transfer rate in order to lower these temperatures. This paper deals with new sintered materials, based on dispersion strengthened copper, used to produce valve seat inserts and valve guides with a superior thermal conductivity. In rig tests these high thermal conductivity valve seat inserts reduced the valve temperature and wear rate. These results were later confirmed in engine tests. The wear results of the copper based materials were comparable to those of the standard series of iron based materials. Initial results of rig tests on the valve guides are reported. The wear rates of the dispersion copper based materials were lower than those of the P/M iron based materials and brass.