Prechamber autoignition of gaseous mixtures: numerical simulation with detailed chemistry and testing on engine test bench
The work accomplished during the second period of the project mainly focused on the experimental evaluation of the prechamber system comparing its performance regarding emissions and efficiency to standard spark ignition mode. Further instrumentation of the engine made it possible to verify that ignition actually takes places inside the prechamber. A system to start up the engine without spark plug was installed and successfully tested. In order to achieve the necessary further improvement of the engine performance, a reduction of the cycle to cycle variations observed during the experimental test runs is absolutely necessary. Two pathways to achieve a more stable operation of the engine were pursued: on the one hand, static mixers were introduced into the intake manifold in order to render the mixture preparation more homogeneous, but did not show the expected improvements. On the other hand, a modification of the prechamber geometry and its influence on the temperature and mixture distribution was investigated via numerical fluid dynamic simulations. These results show an important variation between different geometries and might be used to determine an optimal geometry for optimal mixture preparation for homogeneous ignition conditions inside the prechamber.
Record created on 2008-01-22, modified on 2016-08-08