Experimental Study on Uncertainty in Measurement of Corrected Net Power from Spark-Ignition Methanol Engines
In order to understand and improve the accuracy of corrected net power measurement for spark-ignition methanol engines,an experiment was performed based on a methanol engine to evaluate the uncertainty of corrected net power measurement under the ra-ted condition.The mathematical model of corrected net power was established,and the relative standard uncertainty for each factor(measurement repeatability,accuracy of dynamometer,accuracy of temperature and pressure)was analyzed and evaluated.The evalu-ation result of uncertainty for corrected net power was obtained.Result shows that the average value of corrected net power under the ra-ted condition is 312.43 kW.The combined relative standard uncertainty is 0.28%and the combined standard uncertainty is 0.8868 kW.The expanded uncertainty is 1.7736 kW.From the uncertainty of various factors,it can be seen that the torque measurement has the greatest effect on the uncertainty.The results will provide reference for the accurate measurement of performance in methanol en-gines.
spark-ignition enginecorrected net powercalculation modeluncertaintyinfluencing factor
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