An Analysis on Cycle-by-Cycle Variations of Gasoline Engines Using a Turbulent Combustion Model Considering a Combustion Zone

Abstract

Gasoline engines have cycle-by-cycle variations which prevent the ignition timing advancing. If the cycle-by-cycle variations can be restricted by some measures, that surely contributes fuel economy. So the contributing factors, flow velocity fluctuation in a cylinder, laminar combustion speed and so on, and their contribution ratios on the cycle-by-cycle variations are detected by a turbulent combustion model considering a combustion zone. Comparing its calculation results with the experimental data, some characteristics of the cycle-by-cycle variations are discussed. In addition, in-cylinder brightness through a bore-scope was also measured to detect the cycle-by-cycle variations, so the results from this measurement are shown here.