Selecting the optimal model for estimating the emissions from natural gas vehicles in Tehran

Abstract

Introduction: The study aims to select the optimal model to estimate the emissions from vehicles withcompressed natural gas (CNG) powertrain systems in Tehran to identify, evaluate and plan for controllingemissions through CNG vehicles, and determining the pollution level of passenger cars produced by the Iranianautomotive industries and compare it with pollution standards.Material and methods: In this study, locally-produced CNG vehicles' information was used to estimate thepollutants emitted from domestic CNG vehicles using IVE and COPERT modeling software. Finally, themodeling outputs were compared with the results of the ISQI emission test.Result and discussion: Results showed that contrary to the initial assumption, supposing IVE software wassuitable for advancing the research objectives, the performance of IVE software was not reliable for CNGvehicles, and the outputs of COPERT software were much closer to the values measured in the ISQI emissiontest. The COPERT estimated values were more accurate by 65 and 78 percent for carbon monoxide and NOX,respectively, but 13% worse for carbon dioxide.Conclusion: Based on the findings, the COPERT model is more accurate than IVE for modeling CNG vehicles'emissions, especially for CO and NOX. According to the findings, it is necessary to reconsider the superiorityand application of IVE software for determining the emission inventory and estimating the air pollutantsemitted from the CNG fleet in the country.

Keywords

• emission models
• natural gas vehicle
• ive
• copert
• isqi
• tehran