Prediction of the effect of injection parameters on NO_x emission and burning quality in the direct injection diesel engine using a modified multizone model

Abstract

Combustion process in a quiescent chamber diesel engine is modelled using a multizone model. This model divides the cylinder charge into two zones, namely the unburnt zone (surrounding air) and the burnt zone (fuel spray with entrained air). The burnt zone is subdivided into 16 concentric sprays, instead of only eight sprays as in previous work, each one with its own temperature and composition. Liquid fuel, fuel vapour, air and products of combustion are assumed to be present in each zone. Real gas relations are used to calculate the properties of the mixture while products of combustion are assumed to be in chemical equilibrium at local temperature. The extended Zeldovich mechanism is used to predict the NO x formation. The cylinder pressure, temperature, heat release rate, NO x rate and concentration are calculated. For different injection pressures, injection advance angles and different fuel orifice hole diameters, the results show that the model can predict the measured cylinder pressure with high accuracy but it predicts the measured heat release rate and NO x emission rate with moderate accuracy. In addition, the effect of injection parameters on the NO x emission and engine power is predicted and it has been shown that NO x emission can be reduced without noticeable loss of engine power. This can be done by appropriate choice of injection pressure, injection advance angle and fuel nozzle hole diameters. A cw heat transfer surface area (m 2 ) A ori orifice area (m 2 ) d inj nozzle diameter (m) D cw cylinder bore (m) C d discharge coefficient C pi specific heat of each combustion species (kJ=kg K) f m jet centre-line concentration (kg=m 3 ) h f specific enthalpy of fuel (kJ=kg) h u specific enthalpy of unburnt mixture (kJ=kg) H cw heat convection coefficient (kJ=m 2 ) i inj number of holes in injector L length scale (m) m ae air entrainment mass (kg) m b mass of burnt fuel (kg) m f rate of injected fuel (kg=s) m spray mass of instantaneous spray fuel (kg) m sur mass of instantaneous surrounding air (kg) m u mass of unburnt fuel (kg) n engine speed (r=min) NuNusselt number P pressure (Pa) q w heat transfer rate (kJ=m 2 ) Q f heat absorbed during heating and evaporation (kJ) Q rel released heat during combustion (kJ) r v compression ratio r 0 initial droplet radius (m) R j jet radius (m) s stroke (m) S penetration (m) t time (s) T a surrounding air temperature (K) T ign ignition temperature (K) T m mean charge temperature (K) T spray temperature of instantaneous spray (K) 427 The MS was

Optimization of diesel engine input parameters for reducing hydrocarbon emission and smoke opacity using Taguchi method and analysis of variance

“…Their study provided a guideline to apply Taguchi method for improving the quality of the product and reducing the cost. Salem et al 20 predicted the impact of different injection advance angles, injection pressures, and different nozzle orifice diameters on the NOx emissions using Taguchi approach. From their analysis, it was concluded that the reduction of NOx emission without noticeable loss of power can be achieved by appropriate adjustment of injection parameters.…”

Application of the Taguchi based entropy weighted TOPSIS method for optimisation of diesel engine performance and emission parameters

“…Natarajan et al (2017) studied the effects of injection timing on CI engine fuelled with algae oil blend with Taguchi technique. Salem et al (1998) did optimisation of the NOx emissions using Taguchi method. Win et al (2005) employed Taguchi approach and statistical technique ANOVA to investigate effect of various input parameters on engine noise, emissions and BSFC and also to determine percentage contribution of the input parameters in affecting response variables.…”

Simulation of a Two-Stroke Slow Speed Diesel Engine Using a Quasi-Dimensional Model

“…1. Outside the fuel spray area there is a large remaining zone without fuel (zone without combustion) [5], [6], [7]. Fuel spray packages are spatial creations annular in shape, and in the spray core they have a form of a truncated cone.…”