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Real-Time Exhaust Gas Emission Analysis on Public Transport Buses Equipped with Different Exhaust Control Systems

Viyyuri, Ravi Shankar, viyyuri
http://rave.ohiolink.edu/etdc/view?acc_num=toledo1525131853848906

Abstract Details

2018, Master of Science, University of Toledo, Civil Engineering.
The main objective of this experimental thesis was to present a comprehensive analysis of exhaust emissions from transit buses during daily routine operations. The pollutants monitored in this study are Particulate Matter (PM), NOx, CO2, and HC released from three different buses with different exhaust control systems such as NON-EGR bus, EGR- bus with EGR+DPF+DOC and hybrid bus with EGR+DPF+DOC+SCR. All these buses were tested on the same route each day. To further categorize and elaborate our findings, the runtime was divided into both idle and running conditions. With a specific end goal to accomplish extensive outcomes, the idle condition was additionally divided into two distinct cases, i.e., cold idle and hot idle conditions. The running conditions were also divided into acceleration, deceleration, variable speed, and intersections. The NOx, CO2 and HC emission were gathered and analyzed for every one of the conditions and modes depicted above. The particulate emission was collected and analyzed in idle conditions. In idle condition NOx, CO2 and HC decrease with time and stay constant after they reach 15 minutes of idle time. The cold idle emissions are observed to be very high when compared to the hot idle condition, this is because the hot idle emissions are collected after the bus gets back to the garage from its daily route with a hot engine and this delivers the appropriate amount of fuel into the engine for complete combustion. Whereas cold idle mode does not run at its optimum temperature that leads to incomplete combustion and increases in emission formation. The NOx and HC emissions decreased from NON-EGR to EGR to the hybrid bus because of the emission control systems: SCR, DOC, and EGR, Whereas CO2 emissions, increase by using the same emissions control systems from NON-EGR to EGR to the hybrid bus. The study shows that hybrid bus emits less amount of NOx when compared to EGR and NON- EGR buses, this is because of the exhaust control system SCR. SCR was used to minimize NOx emissions in the exhaust gas by using ammonia (NH3) as the reductant. This exhaust/ammonia mixture passes through the SCR catalyst, where the oxides of nitrogen are turned into nitrogen and water. Moreover, CO2 emissions were high in the hybrid bus then compared to EGR and NON-EGR buses. This was because of chemical reaction that takes place in SCR and DOC releasing CO2 as a product. Whereas, the amount of HC emitted from EGR and hybrid buses were almost in the same range, but very low when compared to the NON-EGR bus. This study also shows that NOx, CO2, and HC are directly proportional to speed (RPM) of the bus. The collected NOx, CO2, and HC are analyzed to develop a statistical regression model using Lasso and Extra Tree Regression techniques that can predict the pollutant concentrations of the exhaust emissions, with respect to different running modes and idle modes for transit buses equipped with EGR+DPF+DOC, EGR+SCR+UREA systems, and a NON-EGR bus. This regression analysis identified the relation and impact of engine variables on pollutant levels. In this study, Extra Tree Regression and Lasso Regression techniques were used to testify the data. The parameters used for prediction of CO2, HC, and NOx emissions in the idle mode were engine temperature and time. Whereas, in running mode rpm was used to predict exhaust emissions. Therefore, Extra Tree Regression was proved as the best regression technique because of its accuracy and low RMSE values when compared to Lasso. Particulate Matter analysis was conducted on all three buses using a catch can instrument and quartz filter papers. Energy Dispersive Spectroscopy (EDS) and Inductively Coupled Plasma Mass Spectroscopy (ICP-MS) was performed on the particulate matter. In EDS analysis, it was observed that the NON-EGR bus samples seem to have a high carbon content detected when compared to EGR bus and Hybrid bus. This was expected because of lack of EGR and DPF systems on NON-EGR bus. Moreover, EGR and Hybrid buses recorded literally the same amount of carbon content, this could be because of having the same exhaust control systems: EGR and DPF. This study and analysis of exhaust emissions for different exhaust control system equipped buses, will assist the manufacturers and regulators of air pollution in selecting the appropriate exhaust control system equipped bus for emission control strategies in their area.
Ashok Kumar (Committee Chair)
Kim Dong Shik (Committee Co-Chair)
Hu Liangbo (Committee Member)
165 p.
Civil Engineering; Environmental Engineering
diesel engine emissions, NOx, CO2, HC, exhaust control systems, biodiesel, public transport buses emission analysis, running conditions, idle conditions

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Citations

  • Viyyuri, viyyuri, R. S. (2018). Real-Time Exhaust Gas Emission Analysis on Public Transport Buses Equipped with Different Exhaust Control Systems [Master's thesis, University of Toledo]. OhioLINK Electronic Theses and Dissertations Center. http://rave.ohiolink.edu/etdc/view?acc_num=toledo1525131853848906

    APA Style (7th edition)

  • Viyyuri, viyyuri, Ravi. Real-Time Exhaust Gas Emission Analysis on Public Transport Buses Equipped with Different Exhaust Control Systems. 2018. University of Toledo, Master's thesis. OhioLINK Electronic Theses and Dissertations Center, http://rave.ohiolink.edu/etdc/view?acc_num=toledo1525131853848906.

    MLA Style (8th edition)

  • Viyyuri, viyyuri, Ravi. "Real-Time Exhaust Gas Emission Analysis on Public Transport Buses Equipped with Different Exhaust Control Systems." Master's thesis, University of Toledo, 2018. http://rave.ohiolink.edu/etdc/view?acc_num=toledo1525131853848906

    Chicago Manual of Style (17th edition)

toledo1525131853848906
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This open access ETD is published by University of Toledo and OhioLINK.