The experimental heat release rate curves are redrawn by taking both premixed and diffusion combustion phase experimental values against appropriate intervals of crank angle (courtesy Miyamoto et. al ). Simulation heat release rate curves are drawn by taking the values synthesized in this work at similar intervals of crank angle. Comparison between simulated and experimental heat release rates with diesel operation at 0.3 MPa bmep and 0.6 MPa bmep are shown in Fig 1 & Fig 2 respectively. The deviation in maximum heat release rate between simulation and experimentation is found lower by 5.7 % and 3.4 % at 0.3 MPa bmep and 0.6 MPa bmep respectively. The efficiency factor ‘a’ is invariably ...view middle of the document...
Figure 1 - Comparison of simulated and experimental heat release rate curve at 0.3 MPa bmep.
Figure 2 - Comparison of simulated and experimental heat release rate curve at 0.6 MPa bmep.
Figure 3 - Comparison of efficiency factors fitted to premixed and diffusion combustion phase.
Figure 4 - Comparison of shape factors fitted to premixed and diffusion combustion phase.
Figure 5 - Comparison of fuel energy release between premixed and diffusion combustion phase.
Figure 6 - Comparison of premixed combustion fuel energy between earlier and present simulation.
Fig – 7 Comparison of simulated heat release rate curves.
Heat release rates are synthesized by applying load correction factor in double Wiebe function model for all power outputs. They have been found agreed with experimental investigation at 0.3 MPa and 0.6 MPa bmep with reasonably acceptable accuracy. Two separate efficiency factors ‘ap’ and ‘ad’ are used for premixed and diffusion combustion phase’s simulation respectively. The efficiency factors ‘ap’ and shape factors ‘md’ for different loads of engine are determined by dividing the values of optimum load with load correction factors (lc). The efficiency factors ‘ap’ and shape factors ‘md’ are not independent on load of the engine. Load correction factors (lc) are the measures of dependency with loads in determining these two factors for different loads. The premixed combustion fuel energy is not found equal to half of the ignition delay period fuel energy in synthesizing diesel engine heat release rate. But this part of fuel energy is found higher than half value at all power outputs lower and higher than optimum power output. This rapid two zone - load correction factor model could provide the necessary baseline support in heat release rate and performance simulation of DICI engine...