Investigation of Spark Position Effects in a Small Pre-chamber on Ignition and Early Flame Propagation

Abstract

<div class="htmlview paragraph">Lean gas engines have a potential for a significant reduction in both fuel consumption and emission levels. The use of a small pre-chamber with controlled stoichiometric or rich mixture composition is an effective way to deal with ignition problems in such engines.</div> <div class="htmlview paragraph">A constant volume vessel equipped with a device for generation of turbulence of known quantities is used to study the operation of a cylindrical pre-chamber of 1% of the main chamber volume. Pressure was measured in the main chamber and Schlieren images of the flame initiation and propagation in the main chamber were recorded for all set-ups.</div> <div class="htmlview paragraph">The investigation of the pre-chamber is focused on the position of the spark within the pre-chamber. Spark locations close to the orifice and close to the opposite wall as well as in the middle of the pre-chamber were tested and flame evolution and pressure history were studied.</div> <div class="htmlview paragraph">The lean limit of ignition was investigated for all spark positions and compared with that of an ignition with a regular spark plug at the main chamber wall at turbulent conditions.</div>