Evaluation of Uncertainty in Measurement of NH 3 Specific Emissions from Diesel Engines
A mathematical calculation model was established for the NH3 pollutant specific emissions of heavy-duty diesel engines in the WHSC cycle test,and the relative standard uncertainty of various param-eters in the model was analyzed through theoretical methods.Finally,the uncertainty evaluation results of NH3 specific emissions were obtained.The relative standard uncertainty of its synthesis is 9.02%.Compar-ing the relative uncertainty of each component,it is found that NH3 has the greatest impact on the uncer-tainty introduced by the repeatability of emission measurement results.Therefore,during the test,it is nec-essary to ensure that the engine and aftertreatment system are in good condition and stable operation,and to strengthen the calibration and maintenance of the emission analysis system.Test operators should be proficient in the operation and principles of the equipment,thereby reducing the uncertainty introduced by measurement repeatability.