Investigation of Injection Concepts to Optimize the Combustion Process for Spray-Guided GDI Methods by Using Optical Techniques

Authors

Harald Bäcker, Milos Tichy, Siemens VDO Automotive AG, Regensburg

Year

2005

Summary

Within Siemens VDO investigations on up-to-date and future injection concepts are performed using a modern single cylinder engine. This passenger car-sized engine shows up-to-date technology features like 500 ccm displacement, 4V, phasing for the intake and exhaust camshafts, boost equipment and combustion chamber design for spray-guided injection with a piezo injector. At this engine several injection strategies are investigated to analyze their specific influence on the combustion process. This is done thermodynamically on the one hand and optically by combustion chamber endoscopy on the other hand to come to an overall judgment. In this paper the test bench and the measurement concept will be introduced as well as the results of the measurements and their potential to optimize the GDI engine process. It could be shown that – aside from the engine thermodynamics – the lift of the intake valves and the stroke of the piston has to be taken into account for designing the injection and ignition strategies. Moreover the dependence on the engine operating condition (engine speed, load, combustion mode) and the charge motion which is induced hereby as well as by other specific measures is of high importance.

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