Diesel EGR-added Hydrogen Combustion And Diesel Exhaust Reforming Chemical Kinetics Modeling

Particulate and NOx emissions are diesel engine major pollutants controlled by the diesel engine itself inherent defects-(particulate-NOX trade-off curve) limit, So it is very difficult to reduce particulate and NOx emissions together. Hydrogen is recognized as ideal energy of internal combustion engine. Diesel EGR (exhaust gas recirculation) with small amounts of hydrogen combustion can not only reduce particulate and NOx emissions effectively, but also improve the economy.In this thesis, EGR,adding hydrogen to diesel and EGR added hydrogen experiments have been carried out on a ZS195 diesel engine. Different ratio of EGR and ratio of hydrogen added to impact on engine emissions and the economic was analyzed and compared under different speed and load. The results show that: adding hydrogen to engine combustion can reduce particulate and NOx in different degrees and improve the effective thermal efficiency.The reformed gas (hydrogen-rich) which produced form diesel exhaust gas catalytic reforming, mixed with the air into the intake manifold and combusted in the cylinder. Diesel engine can improve its performance effectively by using the technology of diesel exhaust gas reforming. This paper introduces the basic concepts and reaction mechanism of diesel exhaust steam reforming.The chemical kinetics model of exhaust gas diesel fuel has been developed using the CHEMKIN platform and n-heptane instead of diesel. The model include gas-phase reaction mechanism and surface reaction mechanism, consists of 57 species and 105 reactions. The simulation compare the gas temperature, water/ carbon ratio, Oxygen/ carbon ratio and space velocity factors impact the reforming process. The simulation results consistent with the experimental with the experimental results well.Under the guide of the simulation conclusions design a suitable diesel exhaust reforming device, which can meet the gas temperature, water/carbon ratio, Oxygen/ carbon ratio and space velocity control requirements. For a more comprehensive understanding of fuel reforming laws laid experimental basis.