Research on a China 6b Heavy-duty Diesel Vehicle Real-world Engine out NOx Emission Deterioration and NOx Correction for Humidity and Temperature using On-board Sensors and Big Data Approach

Abstract

China VI standard proposed higher requirements for durability of heavy-duty diesel vehicles emissions. Previous research which took advantages of both on-board sensors and big data approach to get the NOx deterioration factor was rather scarce. This paper used big data approach to study the deterioration of engine out NOx emission based on 254,622 km operation data getting from the on-board sensors or ECUs. Meanwhile, a formula for on-board NOx correction for ambient humidity and temperature had been fitted. The analyses revealed that engine out NOx would not be deteriorated during the useful life or even longer (deterioration factor was 1.014 @700,000km). For a steady working condition, the engine out NOx mass flow (g/h) is negatively linearly correlated with absolute humidity (R2 = 0.997). If Ha was lower than 12g/kg, Ha almost had no effect on engine out NOx concentration (ppm). Otherwise, there was also a negatively linear relationship between them (R2 = 0.978). It is hoped that the methods and conclusions of this paper could provide some enlightenment for future NOx emission deterioration research.