Looking into the Prechamber of a Lean-Burn Gas Engine

Abstract

Quartz prechamber models have been installed in a constant volume test rig(CVR)for the investigation of prechamber mixing processes. Planar laser induced fluorescence of acetone has been used for a 2-dimensional visualization of flow structure and quantitative analysis of mixture formation. The prechamber was initially filled with acetone seeded in nitrogen. A jet of lean mixture in an actual lean-burn gas engine was simulated using a flow 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 analysis of mixture homogeneity at ignition timing. The investigations provided an insight into the flow structures inside prechambers. The dominant influence of prechamber shape, especially around its mouth, on flow structures as well as on mixture homogeneity at ignition timing was proved.