Experimental investigation on combustion and unregulated emission characteristics of butanol-isomer/gasoline blends

Effects of butanol isomers on characteristics of combustion and emission were studied on PFI SI engine. Experiments were operated under the condition of 3 and 5 bar brake mean effective pressure (BMEP) engine loads and different equivalence ratios (φ=0.83-1.25) with engine speed of 1200 r/min using blends made of 70 vol.% gasoline and 30 vol.% butanol isomers (N30, S30, I30 and T30). The results indicated that compared with gasoline, all butanol isomer blends have higher cylinder pressure. N30 has the highest and most advanced peak pressure, and T30 shows a higher brake specific fuel consumption (BSFC) and lower brake thermal efficiency (BTE). N30 presents a lower UHC emissions and I30 has slightly higher CO emissions than other blends. For unregulated emissions, compared with gasoline, butanol isomer blends have higher acetaldehyde, and N30 produces a higher emission of 1,3-butadiene than other blends. A reduction in benzene, toluene, ethylbenzene and xylene (BTEX) has been found with butanol isomer blends.

Investigation of performance and emission characteristics using ethanol-blended gasoline fuel as a flex-fuel in two-wheeler vehicle mounted on a chassis dynamometer

This study investigated the performance and emissions of flex fuels in a 110-cc BS6-compliant fuel-injected two-wheeler without ethanol adaptation adjustments.The tests were carried out under controlled conditions on a chassis dynamometer at 1000,2000 and 3000 r.p.m.using ethanol blends from 10%ethanol(E10)to 85%ethanol(E85).Parameters examined included brake power(BP)output,brake-specific fuel consumption(BSFC),peak in-cylinder pressure and exhaust temperature.Emissions,including carbon monoxide(CO),hydrocarbons(HC),nitrogen oxide(NOx)and unregulated emissions,were also assessed.As the percentages of the ethanol blend increased from E10 to E85,there was a noticeable improvement in power output.At 1000 r.p.m.,the BP ranged from 2.4 to 4.6 kW for different blends.The BSFC and the peak in-cylinder pressure followed a similar pattern,indicating enhanced performance and fuel efficiency with higher ethanol concentrations.Interestingly,using E85 at 1000 r.p.m.resulted in a significant 41.08%reduction in exhaust temperature compared with E10,although this difference decreased with higher blend percentages.Furthermore,replacing E10 with E85 at 1000 r.p.m.reduced CO and HC emissions by 9.17%and 38.34%,respectively.In contrast,NOx emissions increased at all r.p.m.levels with higher-ethanol blends,peaking at a 415 parts per million increase at 3000 r.p.m.However,unregulated emissions decreased significantly with increased r.p.m.and ethanol content.In summary,the use of flex-fuel blends in a two-wheeler resulted in a modest increase in BP output,improved fuel efficiency and lower CO and HC emissions.These findings are vital for optimizing ethanol blend utilization in two-wheeler engines under low-load conditions,considering both performance and environmental aspects.

Towards low emissions and high thermal efficiency of gasoline compression ignition engine under high loads by modulating the fuel reactivity and injection strategy

Gasoline compression ignition(GCI) is a practicable way to obtain low emissions and high thermal efficiency of gasoline-like fuels in internal combustion engines. In this paper, the research octane number(RON) and injection strategy were coordinated to optimize the GCI engine performance and emissions under high loads. The direct injection and port injection were used to achieve two injection strategies: direct injection(DI) and port injection plus direct injection(PIDI), and the primary reference fuels(PRF) with the RON of 60, 70, 80 and 90 were used. The results show that using lower RON fuels under high loads, DI mode can achieve higher efficiency, while PIDI mode can achieve lower combustion noise at an expense of slightly lower fuel economy. When the DI mode is converted to PIDI mode with a pre-injection ratio of 30%, using PRF70 under 12 bar and the exhaust gas recirculation(EGR) rate of 40%, the gross indicated thermal efficiency and the maximum pressure rise rate are reduced by 1% and by 2 bar/°CA, respectively, while the particle emissions also decrease significantly, thus achieving low emissions and high efficiency. However, under the same load and EGR rate, DI mode produces less regulated and unregulated emissions than PIDI mode. In addition, the effect of fuel RON was obvious, the lower RON fuels exhibit obvious three-stage heat release in PIDI mode, however, PRF90 with higher RON only exhibits two-stage heat release, and the peak value of the firststage heat release rate is also lower than those of other fuels.

Characterization of polycyclic aromatic hydrocarbon emissions from diesel engine retrofitted with selective catalytic reduction and continuously regenerating trap

Two after treatment units, selective catalytic reduction （SCR） and continuously regenerating trap （CRT）, were independently retrofitted to a diesel engine, with the objective to investigate their impact on the conversion/reduction （CR） of polycyclic aromatic hydrocarbons （PAHs）. The experiments were conducted under the European steady state cycle （ESC） first without any retrofits to get baseline emissions, and then with SCR and CRT respectively, on the same engine. The particulate matter （PM）-phase PAHs were trapped in fiberglass filters, whereas gas-phase PAHs were collected in cartridges, and then analyzed using a gas chromatograph-mass spectrometer （GC-MS）. Both PM-phase and gas-phase PAHs were greatly reduced with CRT showing respective CR of 90.7% and above 80%, whereas only gas-phase PAHs were abated in the case of SCR, with CR of above 75%. Lower molecular weight （LMW） PAHs were in abundance, while naphthalene exhibited a maximum relative contribution （RC） to LMW-PAHs for all three cases. Further, the CR of naphthalene and anthracene were increased with increasing catalyst temperature of SCR, most likely due to their conversion to solid particles. Moreover, the Benzo[a]Pyrene equivalent （BaPeq） of PAHs was greatly reduced with CRT, owing to substantial reduction of total PAHs.