Technical Paper
Numerical and Experimental Investigation of the Emission Limits of a DI Diesel Engine without Aftertreatment System
2016-10-17
2016-01-2314
The possible NOx and soot limits that a conventional diesel engine could meet without the assistance of aftertreatment system were investigated on an engineering level. A methodology combining both experiment and numerical simulation was used to evaluate favorable and unfavorable effects of various in-cylinder strategies quantitatively. These strategies or factors include combustion chamber geometry, fuel injection strategy, exhaust gas recirculation (EGR), intake valve close (IVC) timing, and turbocharger. Interactions among these strategies were paid special attention. Two steps to achieve as low as possible emissions were proposed based on analysis of these strategies. The first step would shift the NOx-soot trade-off curve closer to low emission regions via optimization of injection strategy, combustion chamber geometry, IVC, and turbocharger. As a result, NOx and soot could be simultaneously reduced by approximately 14% and 62% respectively.
