LOOKING INTO THE PRECHAMBER OF A LEAN-BURN GAS-ENGINE

Quartz prechamber models have been installed in a constant volume test rig (CVR) for the investigation of prechamber mixing processes. Plana r laser induced fluorescence of acetone has been used for a 2-dimensio nal visualization of flow structure and quantitative analysis of mixtu re formation. The prechamber was initially filled with acetone seeded in nitrogen. a jet of lean mixture in an actual lean-burn gas engine w as simulated using a How of pure nitrogen from the CVR. Two different shapes of prechambers were investigated and the dominant influence on the mixing process is presented. Special emphasis was laid on the anal ysis of mixture homogeneity at ignition timing. The investigations pro vided an insight into the flow structures inside prechambers. The domi nant influence of prechamber shape, especially around its mouth, on fl ow structures as well as on mixture homogeneity at ignition timing was proved.