Comparative Study On Combustion And Emission Characteristics Of Furan/Diesel Blended Combustion And Dual-Fuel Mode

In recent years,in order to cope with the shortage of fossil energy,the rise of oil prices and the proposal of the domestic carbon peaking and carbon neutrality goals,it has become vital to explore clean energy and efficient combustion techniques.Furan is seen as a novel form of green solution because the furan chemical properties are similar to commercial gasoline and could be generated from renewable biomass source.In this article,the combustion tests of furan/diesel based on electronically controlled high-pressure common rail diesel engine fueled with different volume ratios（denoted as D100,D90F10B,D80F20B）and the dual-fuel combustion mode fueled with different energy substitution ratio（denoted as D90F10D,D80F20D）were compared experimentally.According to the test of the blended fuel combustion mode,furan/diesel have better combustion characteristics and a longer ignition delay than D100.D90F10B exhibited higher cylinder pressure when under low and medium load.D80F20B has a greater instantaneous heat release rate when using a single injection strategy;When the poilt-main interval is raised from 8°CA to 14°CA,the peak pressure rise rates of the three fuels decreased by 6.0%,4.3%and 7.2%,respectively;Furan/diesel have more NOx emissions and less soot emissions.While raising EGR rate and delaying the fuel injection time can both reduce NOx emissions.When EGR rate increased to 12%,NOx emission of three fuel decreases by 67.6%,65.5%and 65.8%respectively.But the increase of the poilt-main interval will reduce NOx emission first and then increase it;The increase of load and EGR rate leads to the increase of the proportion of accumulated particles.The increase of average effective pressure and EGR rate leads to the increase of the proportion of accumulated particles;Once the pre-injection technique was removed,the three fuels’soot emissions decreased by 58.1%,44.4%and 10.3%,respectively.According to the test of the dual-fuel combustion mode,when the load of D90F10D reaches 0.70 MPa and all the load conditions of D80F20D,the gas block occurs at the inlet,and the furan/diesel exhibits low cylinder pressure,combustion temperature and pressure rise rate.In most conditions,the dual-fuel mode produces less NOx and soot emissions than D100,but has more HC and CO emissions.With the increase of load and the advance of pre-injection time cause an increase in NO percentage in NOx emission,while the increase of EGR rate and the delay of injection time cause the increase of NO₂percentage in NOx emission.The average HC emission of D90F10D and D80F20D is 6.5 times and 7.2 times that of D100under the single injection strategy,while the average CO emission is 7.9 times and 9.6 times that of D100;In some conditions,D80F20D showed more soot emission than D90F10D.According to the two combustion modes,it is found that the dual-fuel mode has a shorter ignition delay period and a longer combustion duration than the blended fuel mode;The dual-fuel mode can reduce the crude operation of the engine under single injection strategy because the lower pressure rise rate;The NOx emission of D90F10B drops gradually as the EGR rate rises and is higher than that of D90F10D when the EGR rate is 12%.But in other conditions,D90F10D has low NOx emission.But the dual-fuel mode has less soot emissions at low and medium loads.In conclusion,furan/diesel blended fuel mode and dual-fuel mode shows better combustion and emission characteristics than those of pure diesel combustion.Due to the ability of furan to gasify easily,the ESR in dual-fuel mode is constrained.In contrast,the blended fuel combustion mode shows better combustion and economic character,while the dual-fuel combustion mode operates smoothly and has less NOx and soot emissions in some conditions.