Experimental Investigation of Hybrid Homogenous Carbon Nanotube Catalyst Effect on Diesel Fuel Combustion Performance and Emission in Diesel Engines

A hybrid nanocatalyst based on multiwall carbon nanotube was synthesized and added to diesel fuel to improve NOx, CO, uncombustioned hydrocarbons (HC), and soot emissions as well as diesel engine performance including power, torque, and fuel consumption. The applied nanostructure includes the hybrid of cerium oxide and carbon nanotubes of 7-10 nm size, functionalized by an amide group to homogenize the catalyst and fuel mixture. The nanocatalyst was added to the diesel fuel at concentrations of 30, 60, and 90 ppm respectively, and the performance and emissions tests were carried out using OM355 EU2 diesel engine (Idem Co. Iran, under the license of German Mercedes Benz Co.). The nanosized catalyst, and hence the high contact area of the catalyst-fuel, the proper distribution of the catalyst in the fuel, and the occurrence of catalyst oxidation reaction will result in the enhancement of combustion reaction and decreasing the amount of emitted component including NOx (max 17.84%), CO (max 12.7), HC (max 30.77%), and soot (max 20.63%); also, the performance, including a maximum increase of 3.77% and 1.44% respectively in the produced power and torque and a maximum decrease of 4.74% in bsfc, was improved.