Modeling Air Pollutant Emissions from Indian Two-Wheelers: Model Development and Implications for Fleet Emission Rate Estimates 2019-01-0514
Chassis dynamometer tests were conducted on 30 Indian Two-wheelers operating on the Worldwide harmonized Motorcycle Test Cycle (WMTC). Second-by-second (1 Hz) data were collected and used to develop velocity-acceleration look-up table models for emissions of Carbon-di-oxide (CO2), Carbon-mono-oxide (CO), Total Hydrocarbons (THC), oxides of nitrogen (NOx). Models were constructed based on group-average vehicle activity and emissions data to represent the performance of a ‘typical’ vehicle. The models accurately estimated full-cycle emissions for most species. Vehicle emissions data showed large variability for single vehicles (‘intra-vehicle variability’) and within the test group (‘inter-vehicle variability’), complicating the development of a single model to represent a vehicle population. Variability indicated that the model outputs were relatively insensitive to the specific sample of vehicles and that the vehicle samples were likely a reasonable representation of the fleet. Intra-vehicle variability in emissions was also substantial, though had a relatively minor impact on model performance. The models developed in this study can be used to further explore the impact of varying vehicle activity patterns on emissions in efforts to manage air quality and mitigate air pollution exposure and air pollution related health impacts.