Abstract: A method for determining NOx sensor data falsification based on remote emission monitoring, includes the steps of: acquiring a plurality of vehicle data sets and urea level data of to-be-tested reference vehicles, wherein vehicle data include NOx sensor readings and corresponding engine data vectors; acquiring urea level data of reference vehicles; calculating standard urea consumption per kilometer; (2) acquiring an average distribution probability of the vehicle data of the to-be-tested vehicles through a probability distribution evaluation step; counting a total proportion of invalid or negative NOx sensor readings in the plurality of vehicle data sets; determining whether the data of the to-be-tested vehicles satisfy one or more falsification conditions; if so, determining that the data from the NOx sensors of the to-be-tested vehicles are falsified; otherwise, determining that the data from the NOx sensors of the to-be-tested vehicles are not falsified.

Abstract: A method for diagnosing a diesel oxidation catalyst fault includes: obtaining an standard molar enthalpy of formation-revolution speed-load table; obtaining a revolution speed, a load, a temperature difference of front and rear exhaust pipes, and a casing temperature, obtaining an standard molar enthalpy of formation corresponding to the revolution speed and the load from the standard molar enthalpy of formation-revolution speed-load table, and calculating an actual formation enthalpy corresponding to the temperature difference of front and rear exhaust pipes and the casing temperature from the temperature difference of front and rear exhaust pipes and the casing temperature; calculating a standard reaction enthalpy from the standard molar enthalpy of formation and standard conversion efficiency; and diagnosing a diesel oxidation catalyst fault by comparing the actual formation enthalpy with the standard reaction enthalpy.