Experimental investigations on emission in diesel engine using combined nsr scr catalyser

Abstract

The expanding requirement for clean air has pushed vehicle makers to contribute more time and money to reduce toxic emissions. Modification in engine design for better combustion, improved fuel properties to reduce emissions and the utilization of catalytic converters are some of the research areas to obtain clean exhaust.The utilization of monolith catalysts is one of the well-known strategies to clean the exhaust in automotive emissions. Catalytic converters oxidize the destructive carbon monoxide, hydrocarbon emissions into harmless carbon dioxide and water vapour. The toxic NOx exhaust gas components of lean-burn engines cannot be efficiently removed with three-way catalysts, which are effective only under stoichiometric conditions. In this work, a catalytic converter with combined NOx storage and reduction (NSR) and Selective Catalytic Reduction (SCR) was developed and effectiveness towards the NOx reduction from the exhaust of diesel engine was tested. For NSR catalyser prepared by wash coated the monolith with and#947;- alumina to increase its surface area. The next step was the incorporation of the active phase (Pt) followed by Barium incorporation for NOx storage. SCR catalyser was prepared by coating with CU-zeolite and colloidal silica which is used to decompose the NOx into nitrogen. The combination of the NSR and SCR filters helps to build an effective catalytic converter by distinguishing the optimal emission processes.The fabricated NSR-SCR catalytic converter was fitted to the exhaust system and the emission rates were measured with the help of gas analyser. The testing was carried out with diesel as fuel in a multi fuel variable compression ratio Kirloskar engineat a constant speed. The developed prototype with the combination of both NSR and SCR catalyser was fitted to the diesel engine exhaust line with a T-joint to allow a limited amount through the pipe. The testing was completed at different engine operating conditions like different compression ratios ranging from 17.5 to 20 and injection pressures from 180 to 230 bar by applying different load conditions from 0-20 Nm. With the help of the flow regulating valve fitted between the engine exhaust pipe and the prototype exhaust pipe inlet, the flow rate is adjusted. An eddy current dynamometer was utilized to load the engine as per the requirement newline