A Cost-Effective and Fuel-Efficient Solution to Uprating a Diesel Engine Using One-Dimensional/Three-Dimensional Simulation

This paper presents a one-dimensional (1-D)/three-dimensional (3-D) simulation methodology for uprating a diesel engine to reduce production costs and improve fuel economy. The case study is carried out for a baseline multicylinder direct injection (DI) naturally aspirated (NA) diesel engine of 2945 cc, which meets the Central Pollution Control Board (CPCB)-II emission regulations and is used in a 25 kVA genset application. An uprated version of this NA engine is designed to replace a 30 kVA genset turbocharged engine, eliminating the expense of the turbocharger while reducing fuel consumption. The 1-D computational model was calibrated on the 25 kVA base engine and produced a good agreement with the airflow rate, power, brake-specific fuel consumption (BSFC), cylinder pressure, and oxides of nitrogen (NOx) emission levels. Exploratory work was done with the calibrated 1-D model to assess airflow rate requirements for the 30 kVA application, including a parametric analysis for compression ratio (CR), injection timing, and exhaust gas recirculation (EGR). To increase power in the uprated engine, new cylinder head ports were designed using the 3-D computational fluid dynamics (CFD) software Vectis from Ricardo. The newly designed ports compared well with predicted results and overall airflow through the engine, increased by approximately 3%. Piston bowl and fuel injection nozzle characteristics were optimized using the 3-D simulation. An acceptable agreement was found between predicted engine-out emissions and measurements of the 30 kVA genset engine, and good agreement between experiment and computation was found with BSFC. An overall 2-4% fuel efficiency improvement was achieved meeting the CPCB-II emission legislative norms along with a minimum number of experimental tests. Optimum configuration is also verified on the actual canopy where there is better fuel efficiency improvement with comparable overall engine liner surface temperature.