scholarly journals A NOx Emission Model Incorporating Temperature for Heavy-Duty Diesel Vehicles with Urea-SCR Systems Based on Field Operating Modes

Atmosphere ◽  
2019 ◽  
Vol 10 (6) ◽  
pp. 337 ◽  
Author(s):  
Xin Wang ◽  
Guohua Song ◽  
Yizheng Wu ◽  
Lei Yu ◽  
Zhiqiang Zhai
Keyword(s):  
Vehicle Emission ◽  
Nox Emissions ◽  
Emission Model ◽  
Heavy Duty ◽  
Operating Modes ◽  
Diesel Vehicles ◽  
Nox Conversion ◽  
Proposed Model ◽  
Heavy Duty Diesel ◽  
Scr System

The selective catalytic reduction (SCR) is the most commonly used technique for decreasing the emissions of nitrogen oxides (NOx) from heavy-duty diesel vehicles (HDDVs). However, the same injection strategy in the SCR system shows significant variations in NOx emissions even at the same operating mode. This kind of heterogeneity poses challenges to the development of emission inventories and to the assessment of emission reductions. Existing studies indicate that these differences are related to the exhaust temperature. In this study, an emission model is established for different source types of HDDVs based on the real-time data of operating modes. Firstly, the initial NOx emission rates (ERs) model is established using the field vehicle emission data. Secondly, a temperature model of the vehicle exhaust based on the vehicle specific power (VSP) and the heat loss coefficient is established by analyzing the influencing factors of the NOx conversion efficiency. Thirdly, the models of NOx emissions and the urea consumption are developed based on the chemical reaction in the SCR system. Finally, the NOx emissions are compared with the real-world emissions and the estimations by the proposed model and the Motor Vehicle Emission Simulator (MOVES). This indicates that the relative error by the proposed method is 12.5% lower than those calculated by MOVES. The characteristics of NOx emissions under different operating modes are analyzed through the proposed model. The results indicate that the NOx conversion rate of heavy-duty diesel trucks (HDDTs) is 39.2% higher than that of urban diesel transit buses (UDTBs).

Study on Integrated System of SCR and Muffler for Heavy-Duty Diesel Vehicle

2013 ◽  
Vol 427-429 ◽  
pp. 41-44
Author(s):  
Guo Jin Chen ◽  
Zhi Ming Zhang
Keyword(s):  
Performance Optimization ◽  
Technical Problem ◽  
Integrated System ◽  
Nox Emissions ◽  
Heavy Duty ◽  
Diesel Vehicles ◽  
Exhaust Noise ◽  
Heavy Duty Diesel ◽  
Scr System ◽  
The Impact

SCR (Selective Catalytic Reduction) is widely used as a good solution of reducing NOx emissions. For NOx emissions and exhaust noise for heavy-duty diesel vehicles, the paper studied the acoustic performance for the integrated system of SCR and muffler. By analyzing the action of the perforated pipe, the exhaust pressure loss and the impact on the performance of the integrated system, the integrated system was developed for heavy-duty diesel vehicles to solve the technical problem on the integration and performance optimization for the SCR system and muffler structure. Extrusion-type vanadium-based catalyst replaces the current coated-type catalysts, and improves the reduction efficiency. The two-stage rough and fine filter and the heating device for the urea pump are designed to increase the adaptability of the SCR system. The research shows that through the structural improvements, the exhaust noise is reduced by 28.5dB.

scholarly journals On-Board Sensor-Based NOx Emissions from Heavy-Duty Diesel Vehicles

2019 ◽  
Vol 53 (9) ◽  
pp. 5504-5511 ◽  
Author(s):  
Yi Tan ◽  
Paul Henderick ◽  
Seungju Yoon ◽  
Jorn Herner ◽  
Thomas Montes ◽  
...  
Keyword(s):  
Nox Emissions ◽  
Heavy Duty ◽  
Diesel Vehicles ◽  
Heavy Duty Diesel

scholarly journals Research on Optimization Design of SCR Nozzle for National VI Heavy Duty Diesel Engine

Catalysts ◽  
2019 ◽  
Vol 9 (5) ◽  
pp. 452 ◽  
Author(s):  
Feng Qian ◽  
Dong Ma ◽  
Neng Zhu ◽  
Peng Li ◽  
Xiaowei Xu
Keyword(s):  
Diesel Engine ◽  
Conversion Efficiency ◽  
Optimization Design ◽  
Exhaust Pipe ◽  
Heavy Duty ◽  
Deposit Formation ◽  
Nox Conversion ◽  
Heavy Duty Diesel ◽  
Scr System ◽  
Nox Conversion Efficiency

For the National VI heavy-duty diesel vehicles, NOx emission regulations are becoming more and more stringent, and the selective catalytic reduction (SCR) system has become a necessary device. The design of the adblue nozzle in the SCR system is especially critical, directly affecting the NOx conversion efficiency and deposit formation. According to the structure of a National VI diesel engine exhaust pipe and SCR system, the nozzle is optimized by computational fluid dynamics (CFD) method to avoid the collision between the urea droplets and the exhaust pipe wall, to ensure that the exhaust gas and the urea droplets are as much as possible in full contact to ensure a sufficient urea pyrolysis. With the optimized nozzle, the NH3 distribution uniformity of the inlet face of the SCR catalyst can increase from 0.58 to 0.92. Additionally, test verifications are implemented based on the spray particle size test and the engine bench tests; the results show that the Sauter mean diameter of the optimized nozzle is more decreased than the initial nozzle and that the NOx conversion efficiency of the World Harmonized Transient Cycle (WHTC) and World Harmonized Stationary Cycle (WHSC) cycle improves by nearly 3%; additionally, it can also avoid deposit formation.

Evaluation of Cu-PPHs as active catalysts for the SCR process to control NOx emissions from heavy duty diesel vehicles

Chemosphere ◽  
2008 ◽  
Vol 72 (4) ◽  
pp. 608-615 ◽  
Author(s):  
Ramón Moreno-Tost ◽  
Mona Lisa Oliveira ◽  
Dolores Eliche-Quesada ◽  
José Jiménez-Jiménez ◽  
Antonio Jiménez-López ◽  
...  
Keyword(s):  
Nox Emissions ◽  
Heavy Duty ◽  
Diesel Vehicles ◽  
Heavy Duty Diesel

scholarly journals The challenge to NO<sub>x</sub> emission control for heavy-duty diesel vehicles in China

2012 ◽  
Vol 12 (7) ◽  
pp. 18565-18604 ◽  
Author(s):  
Y. Wu ◽  
S. J. Zhang ◽  
M. L. Li ◽  
Y. S. Ge ◽  
J. W. Shu ◽  
...  
Keyword(s):  
Emission Factors ◽  
Operating Conditions ◽  
Nox Emission ◽  
Effective Control ◽  
Emission Measurement ◽  
Nox Emissions ◽  
Heavy Duty ◽  
Diesel Vehicles ◽  
Compliance Testing ◽  
Heavy Duty Diesel

Abstract. China's new "Twelfth Five-Year Plan" set a target for total NOx emission reduction of 10% for the period of 2011–2015. Heavy-duty diesel vehicles (HDDVs) have been considered a major contributor to NOx emissions in China. Beijing initiated a comprehensive vehicle test program in 2008. This program included a sub-task for measuring on-road emission profiles of hundreds of HDDVs using portable emission measurement systems (PEMS). The major finding is that neither the on-road distance-specific (g km −1) nor brake-specific (g kW h−1) NOx emission factors for diesel buses and heavy-duty diesel trucks improved in most cases as emission standards became more stringent. For example, the average NOx emission factors for Euro II, Euro III and Euro IV buses are 11.3±3.3 g km−1, 12.5± 1.3 g km−1, and 11.8±2.0 g km−1, respectively. No statistically significant difference in NOx emission factors was observed between Euro II and III buses. Even for Euro IV buses equipped with SCR systems, the NOx emission factors are similar to Euro III buses. The data regarding real-time engine performance of Euro IV buses suggest the engine certification cycles did not reflect their real-world operating conditions. These new on-road test results indicate that previous estimates of total NOx emissions for HDDV fleet may be significantly underestimated. The new estimate in total NOx emissions for the Beijing HDDV fleet in 2009 is 37.0 Gg, an increase of 45% compared to the previous study. Further, we estimate that the total NOx emissions for the national HDDV fleet in 2009 are approximately 4.0 Tg, higher by 1.0 Tg (equivalent to 18% of total NOx emissions for vehicle fleet in 2009) than that estimated in the official report. This would also result in 4% increase in estimation of national anthropogenic NOx emissions. More effective control measures (such as promotion of CNG buses and a new in-use compliance testing program) are urged to secure the goal of total NOxmitigation for the HDDV fleet in the future.

scholarly journals A Study on the Performance Change of SCR System for Heavy-Duty Diesel Vehicles

2019 ◽  
Vol 27 (5) ◽  
pp. 405-409 ◽  
Author(s):  
Giyoung Park ◽  
Manjae Kwon ◽  
Juyeong Jung ◽  
Hoyoung Song ◽  
Kiho Kim ◽  
...  
Keyword(s):  
Heavy Duty ◽  
Performance Change ◽  
Diesel Vehicles ◽  
Heavy Duty Diesel ◽  
Scr System

scholarly journals The challenge to NO<sub>x</sub> emission control for heavy-duty diesel vehicles in China

2012 ◽  
Vol 12 (19) ◽  
pp. 9365-9379 ◽  
Author(s):  
Y. Wu ◽  
S. J. Zhang ◽  
M. L. Li ◽  
Y. S. Ge ◽  
J. W. Shu ◽  
...  
Keyword(s):  
Emission Factors ◽  
Operating Conditions ◽  
Nox Emission ◽  
Effective Control ◽  
Emission Measurement ◽  
Nox Emissions ◽  
Heavy Duty ◽  
Diesel Vehicles ◽  
Compliance Testing ◽  
Heavy Duty Diesel

Abstract. China's new "Twelfth Five-Year Plan" set a target for total NOx emission reduction of 10% for the period of 2011–2015. Heavy-duty diesel vehicles (HDDVs) have been considered a major contributor to NOx emissions in China. Beijing initiated a comprehensive vehicle test program in 2008. This program included a sub-task for measuring on-road emission profiles of hundreds of HDDVs using portable emission measurement systems (PEMS). The major finding is that neither the on-road distance-specific (g km−1) nor brake-specific (g kWh−1) NOx emission factors for diesel buses and heavy-duty diesel trucks improved in most cases as emission standards became more stringent. For example, the average NOx emission factors for Euro II, Euro III and Euro IV buses are 11.3 ± 3.3 g km−1, 12.5 ± 1.3 g km−1, and 11.8 ± 2.0 g km−1, respectively. No statistically significant difference in NOx emission factors was observed between Euro II and III buses. Even for Euro IV buses equipped with SCR systems, the NOx emission factors are similar to Euro III buses. The data regarding real-time engine performance of Euro IV buses suggest the engine certification cycles did not reflect their real-world operating conditions. These new on-road test results indicate that previous estimates of total NOx emissions for HDDV fleet may be significantly underestimated. The new estimate in total NOx emissions for the Beijing HDDV fleet in 2009 is 37.0 Gg, an increase of 45% compared to the previous study. Further, we estimate that the total NOx emissions for the national HDDV fleet in 2009 are approximately 4.0 Tg, higher by 1.0 Tg (equivalent to 18% of total NOx emissions for vehicle fleet in 2009) than that estimated in the official report. This would also result in 4% increase in estimation of national anthropogenic NOx emissions. More effective control measures (such as promotion of CNG buses and a new in-use compliance testing program) are urged to secure the goal of total NOx mitigation for the HDDV fleet in the future.

scholarly journals NOx Emissions from Euro 5 and Euro 6 Heavy-Duty Diesel Vehicles under Real Driving Conditions

Energies ◽  
2020 ◽  
Vol 13 (1) ◽  
pp. 218 ◽  
Author(s):  
Sangchul Ko ◽  
Junhong Park ◽  
Hyungjun Kim ◽  
Gunwoo Kang ◽  
Jongchul Lee ◽  
...  
Keyword(s):  
Moving Average ◽  
Test Methods ◽  
Test Method ◽  
Emission Measurement ◽  
Nox Emissions ◽  
Vehicle Speed ◽  
Heavy Duty ◽  
Diesel Vehicles ◽  
Gross Vehicle Weight ◽  
Heavy Duty Diesel

Despite the strengthening of vehicle emissions standards and test methods, nitrogen oxide (NOx) emissions from on-road mobile sources are not being notably reduced. The introduction of real driving emission (RDE) regulations is expected to reduce the discrepancy between emission regulations and actual air pollution. To analyze the effects of RDE regulations on heavy-duty diesel vehicles, pollutants emitted while driving were measured using a portable emission measurement system (PEMS) for Euro 5 and Euro 6 vehicles, which were produced before and after RDE regulations, respectively. NOx emissions were compared as a function of emissions allowance standards, gross vehicle weight (GVW), average vehicle speed, and ambient temperature. NOx emissions from Euro 6 vehicles were found to be low, regardless of GVW; emissions from both vehicular categories increased with a decline in the average speed. To reflect real road driving characteristics more broadly in the RDE test method for heavy-duty vehicles, it is necessary to consider engine power, which is a criterion for classifying effective sections, in the moving average window (MAW) analysis method, as well as including cold start conditions.

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