NO_x reduction in the exhaust of mobile heavy-duty diesel engines by urea-SCR

摘要

A DeNO_x demonstration system for a diesel engine used in construction machineries and mobile cranes was setup.In preliminary experiments various extruded and coated SCR catalysts were evaluated with and without oxidizing pre-catalyst.The data from stationary tests with two selected catalysts were used to establish various model-based control algorithms for the optimum dosage of urea in the ESC and ETC.A NO_x conversion of >93% at < 0ppm average ammonia slip could be achieved at a converter-to-swept volume ratio of <2.0.