Experimental study on urea-SCR spray characteristics for diesel engine

Accurate spray quantity control of the urea solution is critical to the performance of the selective catalyst reduction (SCR) system. The factors influencing urea spray quantity, i.e. duty ratio, spray frequency and pressure, liquid density, and with or without air-blast system etc. were studied in the spray test bench. The results show that the spray quantity is linear with spray duty ratio. High spray frequency is hard to realize low dose spray, but low spray frequency conduces system pressure fluctuation. The system pressure fluctuation would result in change of the spray quantity, so it should be kept stable. The spray quantity is directly affected by the liquid density. As to the influence of air-blast system on the spray quantity is not considerable.