Ultra high-speed fuel tracer PLIF imaging in a heavy-duty optical PPC engine
In order to meet the requirement on the stringent emission regulations recently, more and more research works have been focused on homogeneous charge compression ignition (HCCI) and partially premixed combustion (PPC) or partially premixed compression ignition (PCCI) as they have the potentials to produce low NOx and soot emissions without adverse effects on engine efficiency. The mixture formation and stratification charge largely influence the combustion behavior and emissions for PPC/PCCI. An ultra-high speed burst mode laser is used to capture the mixture formation process from the start of injection until several CADs after start of combustion in a single cycle. To the authors’ best knowledge, this is the first time that such a high temporal resolution, i.e. 0.2 CAD, PLIF could be accomplished for imaging of the in-cylinder mixing process. The capability of resolving single cycles allows for the influence of cycle-to-cycle variations to be eliminated.