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This paper presents a special optical fiber technique which allows to measure temperatures in SI engines using the emission bands or respectively emission lines of the temperature radiation of diatomic molecules. The measurement technique enables the detection of average temperature in a small volume element. These temperatures are used to determine the local NO concentrations using the extended Zeldovich-mechanism. First, theoretical background of both temperature and NO-determination and measurement technique including optical fiber sensors are described. Finally, the temperature and NO dependence versus crank angle are presented and discussed at different combustion chamber locations for different engine operating conditions.

In the last decades the operational requirements to control the gas exchange of an internal combustion engine increased immensely. The gas exchange is mainly controlled by the valve train system affecting the combustion behavior and power output of the engine. The necessary valve lift curve must be ensured within the whole operation range of the engine. Moreover, a minimum friction has to be achieved. On the one hand engine speeds and loads of the valve train components have increased and the weights of the components have decreased, on the other hand the demands regarding durability increased as well. The engine development department has tried to find out optimization potentials of valve train dynamics to get along with these challenges. During an engine development process analysis tools together with measurements of the dynamic valve train behavior on motored cylinder heads using Laser Doppler Vibrometry are applied.