Considering the self-ignition characteristic and C/H ratio,n-heptane and toluene(6:4 by mass)are chosen to constitute diesel surrogate fuel,and a reduced oxidation mechanism was developed.This mechanism was firstly va...Considering the self-ignition characteristic and C/H ratio,n-heptane and toluene(6:4 by mass)are chosen to constitute diesel surrogate fuel,and a reduced oxidation mechanism was developed.This mechanism was firstly validated by the combustion of diesel fuel in different oxygen concentrations within a constant volume vessel by high-speed photography.The simulated flame temperature distribution reproduces the diesel combustion process quite well.For further validation,combustion in real diesel engine was also investigated numerically and experimentally using a light duty diesel and a marine diesel.The calculated pressure curves in different operation conditions fit the measured data reasonably well.The oxidation mechanism could reproduce the main characteristics including combustion phase and NOx emission of diesel combustion in different cases.展开更多
Nanocatalysts consisting of three‐dimensionally ordered macroporous(3DOM)TiO2‐supported ultrafine Pd nanoparticles(Pd/3DOM‐TiO2‐GBMR)were readily fabricated by gas bubbling‐assisted membrane reduction(GBMR)method...Nanocatalysts consisting of three‐dimensionally ordered macroporous(3DOM)TiO2‐supported ultrafine Pd nanoparticles(Pd/3DOM‐TiO2‐GBMR)were readily fabricated by gas bubbling‐assisted membrane reduction(GBMR)method.These catalysts had a well‐defined and highly ordered macroporous nanostructure with an average pore size of 280 nm.In addition,ultrafine hemispherical Pd nanoparticles(NPs)with a mean particle size of 1.1 nm were found to be well dispersed over the surface of the 3DOM‐TiO2 support and deposited on the inner walls of the material.The nanostructure of the 3DOM‐TiO2 support ensured efficient contact between soot particles and the catalyst.The large interface area between the ultrafine Pd NPs and the TiO2 also increased the density of sites for O2 activation as a result of the strong metal(Pd)‐support(TiO2)interaction(SMSI).A Pd/3DOM‐TiO2‐GBMR catalyst with ultrafine Pd NPs(1.1 nm)exhibited higher catalytic activity during diesel soot combustion compared with that obtained from a specimen having relatively large Pd NPs(5.0 nm).The T10,T50 and T90 values obtained from the former were 295,370 and 415°C.Both the activity and nanostructure of the Pd/3DOM‐TiO2‐GBMR catalyst were stable over five replicate soot oxidation trials.These results suggest that nanocatalysts having a 3DOM structure together with ultrafine Pd NPs can decrease the amount of Pd required,and that this approach has potential practical applications in the catalytic combustion of diesel soot particles.展开更多
文摘Considering the self-ignition characteristic and C/H ratio,n-heptane and toluene(6:4 by mass)are chosen to constitute diesel surrogate fuel,and a reduced oxidation mechanism was developed.This mechanism was firstly validated by the combustion of diesel fuel in different oxygen concentrations within a constant volume vessel by high-speed photography.The simulated flame temperature distribution reproduces the diesel combustion process quite well.For further validation,combustion in real diesel engine was also investigated numerically and experimentally using a light duty diesel and a marine diesel.The calculated pressure curves in different operation conditions fit the measured data reasonably well.The oxidation mechanism could reproduce the main characteristics including combustion phase and NOx emission of diesel combustion in different cases.
基金supported by the National Natural Science Foundation of China(21673142,21477164)the National High Technology Research and Development Program of China(863 Program,2015AA030903)~~
文摘Nanocatalysts consisting of three‐dimensionally ordered macroporous(3DOM)TiO2‐supported ultrafine Pd nanoparticles(Pd/3DOM‐TiO2‐GBMR)were readily fabricated by gas bubbling‐assisted membrane reduction(GBMR)method.These catalysts had a well‐defined and highly ordered macroporous nanostructure with an average pore size of 280 nm.In addition,ultrafine hemispherical Pd nanoparticles(NPs)with a mean particle size of 1.1 nm were found to be well dispersed over the surface of the 3DOM‐TiO2 support and deposited on the inner walls of the material.The nanostructure of the 3DOM‐TiO2 support ensured efficient contact between soot particles and the catalyst.The large interface area between the ultrafine Pd NPs and the TiO2 also increased the density of sites for O2 activation as a result of the strong metal(Pd)‐support(TiO2)interaction(SMSI).A Pd/3DOM‐TiO2‐GBMR catalyst with ultrafine Pd NPs(1.1 nm)exhibited higher catalytic activity during diesel soot combustion compared with that obtained from a specimen having relatively large Pd NPs(5.0 nm).The T10,T50 and T90 values obtained from the former were 295,370 and 415°C.Both the activity and nanostructure of the Pd/3DOM‐TiO2‐GBMR catalyst were stable over five replicate soot oxidation trials.These results suggest that nanocatalysts having a 3DOM structure together with ultrafine Pd NPs can decrease the amount of Pd required,and that this approach has potential practical applications in the catalytic combustion of diesel soot particles.
