Project Details
Projekt
Experimental investigation on cyclic variations and combustion anomalies in modern H2 DI engines
Subject Area
Energy Process Engineering
Term
since 2019
Project identifier
Deutsche Forschungsgemeinschaft (DFG) - Project number 349537577
In this subproject, fundamental questions concerning combustion anomalies of hydrogen in a direct-injection engine are clarified in order to contribute to the understanding of the mechanisms of hydrogen auto-ignition behavior in connection with cyclic variations. The subproject has two main objectives. The first objective is the analysis of surface-induced ignition phenomena for premixed combustion of hydrogen at static thermodynamic boundary conditions under variation of individual test parameters in a fundamental experiment. To this end, an experimental setup for a high-pressure chamber is first developed and constructed to enable optical investigations of the auto-ignition of a premixed air-hydrogen mixture under controlled boundary conditions. By combining different optical measurement techniques, a detailed understanding of the auto-ignition behavior of hydrogen at a controlled hotsurface in a high-pressure chamber is aimed at. In parallel to the high-pressure chamber investigations, numerical simulations are performed to determine the wall temperature profiles in the engine, which are of great importance for the interpretation of the following experiments in a single-cylinder engine. Furthermore, the wall temperatures will be provided for the scale-resolving simulations (LES) in TP 7. The second objective is the analysis of combustion anomalies in engine operation with direct injection. In a first measurement phase, the influence of a hot surface on auto-ignition and combustion is investigated under variation of various operating parameters by inserting a temperature-adjustable surface into the combustion chamber and by means of optical measurement technology In the second measurement phase, the influence of targeted mixture stratification through a time-delayed secondary injection of hydrogen will be analyzed. Findings from the fundamental experiment will contribute to the understanding and interpretation of the observed combustion phenomena. In addition, a comparison of the experimental data with the high-resolution 3D-CFD simulations by TP 7 is pursued in order to jointly evaluate the formation processes of combustion anomalies (pre-ignition or surface-induced ignitions and knocking) as well as their dependence on local cyclic variations along the entire chain of cause and effect.
DFG Programme
Research Units
