Experimental monitoring of pollutants emissions from road vehicles

• Autor(a) principal: Amorim, Paulo Miguel Azevedo
• Data de Publicação: 2020
• Tipo de documento: Dissertação
• Idioma: eng
• Título da fonte: Repositório Científico de Acesso Aberto de Portugal (Repositórios Cientìficos)
• Texto Completo: http://hdl.handle.net/10773/31341
• topic: Driving style; Emission rates; Emission monitoring; Portable emissions measurement system; Real driving emissions; Vehicular jerk; Vehicle specific power

It is well-known the inconstancy that is verified on the obtained laboratorytest values, which present emission rates that are below the ones that are verified on the field. In order to achieve more reliable values the use of the Portable Measurement Emissions System (PEMS) is becoming more popular among researchers who work on this area. The main objective of this masters dissertation was to conduct an experimental monitoring of tailpipe pollutant emissions from different vehicles, with different types of fuels and routes. It was accomplished by the development of an empirical method which embraced vehicle data collection regarding its operating conditions and its consequent emissions. The two main purposes of the development of this method were to be able to, firstly, observe what were the impacts that different driving style parameters, such as the acceleration, vehicular jerk or RPM, along with the Vehicle Specific Power (VSP) and the characteristics of the route, had on the emission rates of the CO2, NOx and PM; and, secondly, to be able to analyze the relationship between the VSP and the obtained onroad emission rates by developing predictive based-modal approach. Two vehicles were submitted to the tests, being one of them ran by gasoline and the other by diesel, along four different routes, being two of them performed on highways, one on a partly urban/rural road and one along urban roads. Testing vehicles were equipped with a PEMS, a Global Positioning System (GPS) and an On-Board Diagnostic (OBD) scan device that were used to collect data about exhaust emissions, location and engine parameters, respectively. For both vehicles and in the intercity routes, the variance of the acceleration and the vehicular jerk was significantly high at low and moderate speeds, namely from 0-20 km/h and from 60-90 km/h, compared to the remaining ones. It was concluded that the NOx Euro 6 limit was surpassed in about 44 times and in 66% by the diesel and the gasoline vehicle, respectively. Results showed that both cars were below the PM limits defined for their corresponding emission standards. Regarding the VSP-based prediction model approach and in the case of the diesel vehicle, high determination coefficients were obtained for the CO2 and for the NOx (R2 > 0.9) and a moderate coefficient was obtained for the PM (R2 > 0.6). VSP model showed as effective in predicting emissions in the gasoline vehicle, regardless of the pollutant (R2 > 0.83). Regarding the validation of the VSP-based prediction model and for the diesel vehicle, the average VSP predicted values for the CO2, NOx and PM were 8 and 28% higher and 46% lower than the ones measured on the field, respectively. In the case of the gasoline vehicle and for the same pollutants, these values were 7, 20 and 33% superior to the field ones, respectively. The implementation of an effective method such as the VSP-based one is useful to estimate emissions in diesel or gasoline vehicles for all types of driving cycles and it could be incorporated on national inventories in order to calculate traffic emissions, for instance.