Improving Diesel Engine Fuel Efficiency over Transient Cycle Using 1-D Thermodynamic Simulation 02-15-02-0005

Air pollution problems persist in many cities throughout the world despite drastic reductions in regulated emissions of vehicle pollutants when tested on a standardized driving cycle. New vehicle emissions regulations in India require the use of a non road transient cycle (NRTC) to confirm vehicles meet specified emission limits. Previous emission norms were comfortably meeting with the mechanical injection system. But the current stringent emission norms require a common rail direct injection (CRDI) system to meet the lower particulate matter (PM) limits. This article discusses on improving the engine fuel efficiency and nitrogen oxides (NOx) emission prediction on a transient cycle using a one-dimensional (1-D) software by coupling Ricardo WAVE and Ricardo Vectis. Engine fuel consumption and emission maps are predicted using Ricardo WAVE. These maps are input into Ricardo IGNITE for predicting cumulative fuel consumption and NOx emission. In general, total simulated fuel use and NOx emissions were within 10% of the observed values for the base engine, which is with a mechanical injection system. The same approach is applied for predicting cumulative fuel consumption and overall emission for modified configuration with CRDI. A good correlation is observed between the predicted and simulated values that gives great confidence for going ahead with more parametric study and avoiding unnecessary engine test bed operating costs. It is observed that engine fuel efficiency can be improved by 5% over a transient cycle if the conventional mechanical injection system is replaced with a CRDI system.