Optimization of fuel injection parameters and strategies in diesel engine using CFD

Abstract

Fuel consumption in the world is increasing at alarming rate as well as fossil fuels prices are increasing day by day. It would be necessary to use fuels in an efficient manner such that extracting more energy from given fuel inside the system. IC engine is one of the high fuel consumption sectors, and it needs to concentrate on the IC engine combustion. In this project, diesel engine has been taken for analysis to improve the combustion and emissions. The piston bowl geometry, nozzle position and spray behavior play a predominant role in the engine performance. The most important role of the Compression Ignition (CI) engine combustion chamber is to enhance the fuel-air mixing rate (swirl) in short possible time. The turbulence can be guided by the shape of the combustion chamber and fuel injection method. Here, nozzle injection parameters and strategies have been taken for the study. Nozzle protrusion depth inside the combustion chamber, number of holes in the injector, injector angle and spray cone angle and longer spray volumes are nozzle injection parameters. When optimizing those parameters for the given engine geometry, it gives better fuel economy, lower hydrocarbons (HC), smoke, carbon monoxide (CO), greater brake thermal efficiency (BTE) and maximum cylinder pressure and it is attributed to higher in turbulence, swirl and fuel atomization. Parameters considered for this work are nozzle protrusion depth, number of injection holes, spray cone angle, swirl number. All the above investigation would be simulated using computational fluid dynamics (CFD). Initially, intake and compression stroke analysis would be carried out to calculate combustion chamber flow characteristics like pressure, temperature, swirl ratio, tumble ratio. These results would be considered as initial conditions for combustion analysis. Combustion analysis would be carried out for different nozzle injection parameters and compared based on fuel air mixing, pressure and heat release from combustion. Finally, pollutant emission prediction also can be studied.