The Design Of Fuel Reforming Reactor And Experimental Study On Effect Of Syngas Addition On Performance Of Internal Combustion Engines

In recent years, the increase in the number of vehicles has led to a great rise infuel consumption and environmental pollution. This drives researchers to developnew technologies to reduce vehicle fuel consumption and emissions. The fuelconsumption and emissions can be reduced by the mixed combustion of traditionalfuel and the hydrogen-rich reformed gas，which is produced by the fuel catalyticreforming using engine exhaust heat. In this paper, a fuel reforming reactor and areforming experimental apparatus using the engine exhaust heat were designed toproduce hydrogen-rich gas.The reforming reactor was designed based on thermodynamic analysis. Theconfiguration and size of this reactor were determined through the heat balancecalculation of the fuel combustion. Subsequently, using the simulation code ANSYSand FLUENT, a thermal analysis was conducted to predict the temperaturedistribution and heat transfer process for different arrangements of the heat tubesand material access ports.After determining the structure and size of the reactor, we established a fuelreforming apparatus which is used to produce hydrogen using engine exhaust heat.At first, the fuel was pushed into the reactor by a micro-pump. Then the exhaust gasexchanged heat with fuel and catalyst through the heat pipes. The exhaust gas whichis flowed into the heat pipes released heat to vaporize the liquid fuel. The catalystcould be kept a certain temperature by absorbing heat. Finally, the reforming gas,which mainly includes hydrogen and carbon monoxide, and small amounts ofmethane and carbon dioxide, was produced by the reforming reaction. The reformedgas was pumped into the cylinders to mix with engine fuel by an air pump.In the engine test, engine intake and exhaust pipes were modified, and ahomemade ethanol reforming unit was installed outside of the engine. Theexperiments were carried out under an engine speed of1800rpm and a manifoldsabsolute pressure of61.5kPa to investigate the effect of reformed gas addition onthe engine performance under different excess air ratio and reformed gas additionlevels. The results showed that, hydrogen in the reformed gas was increased and COwas reduced with the increase of excess air ratio. The blending of reformed gascould shorten the flame development duration and reducing HC emissions. However,the emissions of CO and NOXwere slightly increased after the reformed gasaddition.