Effects of Diesel Exhaust Fluid (DEF) Injection Configurations on Deposit Formation in the SCR System of a Diesel Engine

2016 ◽  
Author(s):  
Vikram Betageri ◽  
Mahesh Rajagopalan ◽  
Sandeep Dhakshina Murthy ◽  
Ashwin Thondavadi
Keyword(s):  
Diesel Engine ◽  
Diesel Exhaust ◽  
Deposit Formation ◽  
Scr System ◽  
Diesel Exhaust Fluid

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.

Analysis of deposit formation mechanism and structure optimization in urea-SCR system of diesel engine

Fuel ◽  
2020 ◽  
Vol 265 ◽  
pp. 116941 ◽  
Author(s):  
Haozhong Huang ◽  
Yajuan Chen ◽  
Zhihua Li ◽  
Hui Wang ◽  
Bin Hao ◽  
...  
Keyword(s):  
Diesel Engine ◽  
Formation Mechanism ◽  
Structure Optimization ◽  
Deposit Formation ◽  
Scr System

scholarly journals Structural Analysis of Pump Gear of Urea-SCR System for Diesel Engine

2016 ◽  
Vol 24 (1) ◽  
pp. 10-15
Author(s):  
Hongyoon Lee ◽  
Chungyeol Park ◽  
Hyungmin Kim ◽  
Sejin Kim ◽  
Dooseuk Choi
Keyword(s):  
Diesel Engine ◽  
Structural Analysis ◽  
Scr System

scholarly journals Investigation of Urea Uniformity with Different Types of Urea Injectors in an SCR System

Catalysts ◽  
2020 ◽  
Vol 10 (11) ◽  
pp. 1269
Author(s):  
Muhammad Khristamto Aditya Wardana ◽  
Kwangchul Oh ◽  
Ocktaeck Lim
Keyword(s):  
Diesel Engine ◽  
Catalytic Reduction ◽  
Nox Reduction ◽  
Heavy Duty ◽  
Ammonia Gas ◽  
Experimental Parameters ◽  
Heavy Duty Diesel Engine ◽  
Heavy Duty Diesel ◽  
Scr System

Heavy-duty diesel engines in highway use account for more than 40% of total particulate and nitrogen oxide (NOx) emissions around the world. Selective catalytic reduction (SCR) is a method with effective results to reduce this problem. This research deals with problems in the urea evaporation process and ammonia gas distribution in an SCR system. The studied system used two types of urea injectors to elucidate the quality of ammonia uniformity in the SCR system, and a 12,000-cc heavy-duty diesel engine was used for experimentation to reduce NOx in the system. The uniformity of the generated quantities of ammonia was sampled at the catalyst inlet using a gas sensor. The ammonia samples from the two types of urea injectors were compared in experimental and simulation results, where the simulation conditions were based on experimental parameters and were performed using the commercial CFD (computational fluid dynamics) code of STAR-CCM+. This study produces temperatures of 371 to 374 °C to assist the vaporization phenomena of two injectors, the gas pattern informs the distributions of ammonia in the system, and the high ammonia quantity from the I-type urea injector and high quality of ammonia uniformity from the L-type urea injector can produce different results for NOx reduction efficiency quality after the catalyst process. The investigations showed the performance of two types of injectors and catalysts in the SCR system in a heavy-duty diesel engine.

scholarly journals Diesel exhaust nanoparticles and their behaviour in the atmosphere

2018 ◽  
Vol 474 (2220) ◽  
pp. 20180492 ◽  
Author(s):  
Roy M. Harrison ◽  
A. Rob MacKenzie ◽  
Hongming Xu ◽  
Mohammed S. Alam ◽  
Irina Nikolova ◽  
...  
Keyword(s):  
Diesel Engine ◽  
Size Distribution ◽  
Diesel Exhaust ◽  
Dynamical Behaviour ◽  
Air Pollutant ◽  
Diesel Exhaust Particles ◽  
Atmospheric Conditions ◽  
Engine Exhaust ◽  
Number Count ◽  
Model Studies

Diesel engine emissions are by far the largest source of nanoparticles in many urban atmospheres, in which they dominate the particle number count, and may present a significant threat to public health. This paper reviews knowledge of the composition and atmospheric properties of diesel exhaust particles, and exemplifies research in this field through a description of the FASTER project (Fundamental Studies of the Sources, Properties and Environmental Behaviour of Exhaust Nanoparticles from Road Vehicles) which studied the size distribution—and, in unprecedented detail, the chemical composition—of nanoparticles sampled from diesel engine exhaust. This information has been systematized and used to inform the development of computational modules that simulate the behaviour of the largely semi-volatile content of the nucleation mode particles, including consequent effects on the particle size distribution, under typical atmospheric conditions. Large-eddy model studies have informed a simpler characterization of flow around the urban built environment, and include aerosol processes. This modelling and engine-laboratory work have been complemented by laboratory measurements of vapour pressures, and the execution of two field measurement campaigns in London. The result is a more robust description of the dynamical behaviour on the sub-kilometre scale of diesel exhaust nanoparticles and their importance as an urban air pollutant.

A Chronic Inhalation Toxicity Study of Diesel Engine Emissions and Coal Dust, Alone and Combined

1989 ◽  
Vol 8 (2) ◽  
pp. 345-375 ◽  
Author(s):  
T. R. Lewis ◽  
F. H.Y. Green ◽  
W. J. Moorman ◽  
J. R. Burg ◽  
D. W. Lynch
Keyword(s):  
Body Weight ◽  
Diesel Engine ◽  
Diesel Exhaust ◽  
Coal Dust ◽  
Ambient Air ◽  
Female Rats ◽  
Dust Particles ◽  
Engine Emissions ◽  
Diesel Particulate ◽  
Diesel Engine Emissions

To evaluate the potential health hazards of diesel engine emissions in underground coal mines, inhalation studies were performed using three species of animals. A wide range of toxicological responses was measured. Exhaust was provided by a 425 in.3 displacement four-cycle, water-cooled, naturally aspirated diesel engine (Caterpillar Model 3304) equipped with a water scrubber. Exposures were 7 h/day, 5 days/week, for periods up to 24 months. Micronized coal dust was generated using a Wright dust feeder. Four exposures were evaluated: (1) filtered ambient air, (2) 2 mg/m3 diesel particulate, (3) 2 mg/m3 respirable coal dust, and (4) 1 mg/m3 each of 2 and 3. Gaseous and vapor concentrations were similar in both exposures employing diesel exhaust. Male cynomolgus monkeys, Fischer-344 male and female rats, and female CD-1 mice were the experimental subjects. Monkeys were sacrificed at 24 months, rats at 3, 6, 12, and 24 months, and mice at 1, 3, and 6 months. Gross morphology and histopathology demonstrated that both diesel and coal dust particles are deposited in the lungs and retained in alveolar tissue. Alveolar type II cell hyperplasia and pulmonary lipidosis occurred in rats, being most evident in rats exposed to diesel exhaust alone. There was, however, no evidence of emphysema or chronic bronchitis, and only minimal fibrosis was seen in association with the retained particulate. Both particulates affected the defense mechanisms of the lung. Exposure to coal dust activated responses associated with phagocytosis, whereas exposure to diesel exhaust depressed them. Severity of influenza challenge increased concomitantly with decreased interferon production in diesel-exposed mice. Exposure to diesel emissions did not result in genotoxic effects as measured by increases in sister chromatid exchange, chromosomal aberrations, micronucleus testing, and urine genotoxic assays. Pulmonary function studies in monkeys showed mild obstructive airway disease in coal dust, diesel exhaust, and the combined exposed animals. This effect was most pronounced in monkeys exposed to diesel exhaust. Evidence of restrictive lung disease was not seen in any group. Clearance of F3O4 particles appeared to be stimulated by exposure to diesel exhaust in the first 3 months, but long-term clearance of diesel particulate appeared to be inhibited. No evidence was found for increases in tumorogenicity (rats) or induction of xenobiotic metabolizing enzymes in the lung or liver (rats). Humoral and cellular immunities were not significantly affected by exposure (rats). No adverse seminal effects were observed in monkeys exposed for 2 years. There was no frank evidence of chronic toxicity as demonstrated by changes in mortality, body weight gains, organ-body weight ratios, or clinical parameters in rats or monkeys. Synergistic effects between diesel exhaust and coal dust were not demonstrated.

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