Experimental Study of Urea Depositions in Urea-SCR System

2014 ◽  
Vol 937 ◽  
pp. 74-79 ◽  
Author(s):  
Shu Zhan Bai ◽  
Shuai Guo Lang ◽  
Ke Ping Yuan ◽  
Yang Liu ◽  
Guo Xiang Li
Keyword(s):  
Control Strategy ◽  
Structural Design ◽  
Cyanuric Acid ◽  
Exhaust System ◽  
Structure Design ◽  
Exhaust Pipe ◽  
Front End ◽  
Urea Crystallization ◽  
Exhaust Stream ◽  
Scr System

Avoiding the urea deposition in the exhaust stream is one of the basic requirements for SCR system normal application. Unreasonable structure design, machining and installation position all could lead to urea crystallization on the wall of exhaust pipe and the front end surface of the catalyst, in addition, unreasonable control strategy also could deteriorate this phenomenon. The components of the urea depositions are the urea and cyanuric acid analyzed by thermogravimetry - FTIR technology. The integrated injector mounting is designed to alleviate the urea crystallization based on analysis results. The engine test and the vehicle road test are all shown that the optimal structural design and calibration strategies could avoid crystallization and sedimentation effectively in the exhaust system.

Measurement of cycle-resolved engine-out soot concentration from a diesel-pilot assisted natural gas direct-injection compression-ignition engine

2021 ◽  
pp. 146808742098626
Author(s):  
Pooyan Kheirkhah ◽  
Patrick Kirchen ◽  
Steven Rogak
Keyword(s):  
Response Time ◽  
Internal Combustion Engines ◽  
Fuel Injection ◽  
Exhaust System ◽  
Cycle Period ◽  
Scanning Mobility Particle Sizer ◽  
Compression Ignition Engine ◽  
Engine Operation ◽  
Exhaust Port ◽  
Exhaust Stream

Exhaust-stream particulate matter (PM) emission from combustion sources such as internal combustion engines are typically characterized with modest temporal resolutions; however, in-cylinder investigations have demonstrated significant variability and the importance of individual cycles in transient PM emissions. Here, using a Fast Exhaust Nephelometer (FEN), a methodology is developed for measuring the cycle-specific PM concentration at the exhaust port of a single-cylinder research engine. The measured FEN light-scattering is converted to cycle-resolved soot mass concentration ([Formula: see text]), and used to characterize the variability of engine-out soot emission. To validate this method, exhaust-port FEN measurements are compared with diluted gravimetric PM mass and scanning mobility particle sizer (SMPS) measurements, resulting in close agreements with an overall root-mean-square deviation of better than 30%. It is noted that when PM is sampled downstream in the exhaust system, the particles are larger by 50–70 nm due to coagulation. The response time of the FEN was characterized using a “skip-firing” scheme, by enabling and disabling the fuel injection during otherwise steady-state operation. The average response time due to sample transfer and mixing times is 55 ms, well below the engine cycle period (100 ms) for the considered engine speeds, thus suitable for single-cycle measurements carried out in this work. Utilizing the fast-response capability of the FEN, it is observed that cycle-specific gross indicated mean effective pressure (GIMEP) and [Formula: see text] are negatively correlated ([Formula: see text]: 0.2–0.7), implying that cycles with lower GIMEP emit more soot. The physical causes of this association deserve further investigation, but are expected to be caused by local fuel-air mixing effects. The averaged exhaust-port [Formula: see text] is similar to the diluted gravimetric measurements, but the cycle-to-cycle variations can only be detected with the FEN. The methodology developed here will be used in future investigations to characterize PM emissions during transient engine operation, and to enable exhaust-stream PM measurements for optical engine experiments.

Kinematics and Dynamics Simulation Research for Roller Coaster Multi-Body System

2011 ◽  
Vol 421 ◽  
pp. 276-280 ◽  
Author(s):  
Ge Ning Xu ◽  
Hu Jun Xin ◽  
Feng Yi Lu ◽  
Ming Liang Yang
Keyword(s):  
Structural Design ◽  
3D Model ◽  
Structure Design ◽  
Dynamics Simulation ◽  
Body System ◽  
Load Spectrum ◽  
Roller Coaster ◽  
Simulation Research ◽  
Calculation Results ◽  
Multi Body

To assess the roller coaster multi-body system security, it is need to extract the running process of kinematics, dynamics, load spectrum and other features, as basis dates of the roller coaster structural design. Based on Solidworks/motion software and in the 3D model, the calculation formula of the carrying car velocity and acceleration is derived, and the five risk points of the roller coaster track section are found by simulation in the running, and the simulation results of roller coaster axle mass center velocity are compared with theoretical calculation results, which error is less than 4.1%, indicating that the calculation and simulation have a good fit and providing the evidence for the roller coaster structure design analysis.

Automation of seismic design of high-rise structure with braced steel frame

2021 ◽  
Author(s):  
Xin Zhao ◽  
Gang Wang ◽  
Jinlun Cai ◽  
Junchen Guo
Keyword(s):  
Seismic Performance ◽  
Seismic Design ◽  
Structural Design ◽  
Structure Design ◽  
Steel Frame ◽  
Design Methods ◽  
Automatic Design ◽  
Component Level ◽  
Design Algorithm ◽  
High Rise

<p>With the continuous development and progress of society, the structure of high-rise buildings has been paid more and more attention by the engineering community. However, the existing high- rise structure design methods often have a lot of redundancy and have a lot of room for optimization. Most of the existing seismic design methods of high-rise structures are based on engineering experience and manual iterative methods, so that the efficiency of design can not meet the needs of the society. if the method of design automation is adopted, the workload of designers can be greatly reduced and the efficiency of structural design can be improved. Based on the digital modeling theory, this paper proposes a MAD automatic design algorithm, in which the designer provides the initial design of the structure, and the algorithm carries out the modeling, analysis, optimization and design of each stage of the structure, and finally obtains the optimal structure. The structural design module of this algorithm starts from the component level, when the component constraint design meets the limit requirements of the specification, it enters and completes the component constraint design and the global constraint design of the structure in turn. In this paper, taking a ten-story braced steel frame high-rise structure as an example, the optimal design is carried out, and its seismic performance is analyzed. the results show that the MAD automatic design algorithm can distribute the materials to each part reasonably, which can significantly improve the seismic performance of the structure and realize the effective seismic design.</p>

scholarly journals Structure design and reliability analysis of Al-Ti lugs

2021 ◽  
Vol 39 (1) ◽  
pp. 1-8
Author(s):  
Yunwen Feng ◽  
Jiale Zhang ◽  
Xiaofeng Xue ◽  
Xiaoping Zhong ◽  
Wei Xie
Keyword(s):  
Reliability Analysis ◽  
Structural Design ◽  
Design Principle ◽  
Load Transfer ◽  
Design Method ◽  
Static Strength ◽  
Structure Design ◽  
Safety Design ◽  
Design Requirements ◽  
Metal Materials

Aircraft lug joint is the key part of load transfer. In order to improve the safety of lug joint, on the premise of meeting the design requirements of static strength and fatigue, the composite connection lug structure design technology of different metal materials is proposed in this paper. Firstly, the damage safety design and life reliability analysis of the lug structure are studied theoretically. Secondly, based on the concept of damage safety design and the design principle of deformation coordination, the design method of composite connection lug with deformation coordination is proposed, and the thickness ratio of single ear is 0.8:1:0.8. Finally, the reliability of the composite lug is analyzed. The results show that the structural design scheme of aluminum-titanium composite ear piece can meet the requirements of static strength and damage tolerance, and compared with the conventional ear structure, the failure probability of structure mission life is greatly reduced when the weight of the composite connection lug is only increased by 4.9%. The proposed method can effectively guide the structural design of composite ear piece.

scholarly journals Discussion on Prefabricated Concrete Structure Design Method under BIM Technology

2020 ◽  
Vol 198 ◽  
pp. 03011
Author(s):  
Wang Hongyan ◽  
Zhang Zihong
Keyword(s):  
Life Cycle ◽  
Structural Design ◽  
Concrete Structure ◽  
Production Efficiency ◽  
Design Method ◽  
Collaborative Work ◽  
Structure Design ◽  
Building Information ◽  
Correct Understanding ◽  
Design Construction

BIM is a data tool used in various stages of design, construction and management. It can integrate different models of buildings and realize sharing and transmission during the life cycle of the project, ensuring that engineering technicians can access different building information with a correct understanding and real-time response, it lays a good foundation for different participants including design, construction and management to achieve collaborative work. It is very important whether it is to ensure production efficiency, save costs and shorten construction periods. For the newly emerging prefabricated buildings, their structural design will become more efficient, accurate and reasonable due to the introduction of BIM technology.

Structural Design of the Robot Arm for Massage Based on the Chain Drive

2012 ◽  
Vol 605-607 ◽  
pp. 1547-1551
Author(s):  
Zhan Li Wang ◽  
Qian Liang ◽  
Bang Cheng Zhang
Keyword(s):  
Structural Design ◽  
Elbow Joint ◽  
Structure Design ◽  
Robot Arm ◽  
Chain Drive ◽  
Element Analysis ◽  
Overall Design ◽  
Transfer Mode ◽  
Design Requirements ◽  
Robot Technology

With the development of robot technology, massage robot has attracted fully attention, and the study about robot arm has been a growing interest in the area of massage robot. This article has put forward a new massage robot arm, which uses the chain as the main transfer mode by the requirements of the overall design massage of the robot arm. The design of big arm, shoulder joint, forearm, elbow joint and wrist are introduced. Based on the design requirements, we made some improvements with sprockets, ensuring transmission conditions and meeting the massage requirements. And finite element analysis for the designed arm, results show that the structure design can meet the requirements.

An Experimental Study for NOx - Emission Reduction with Urea-SCR Technology in Vehicular Diesel Engines

2011 ◽  
Vol 71-78 ◽  
pp. 2089-2093 ◽  
Author(s):  
Qian Wang ◽  
Ming Xing Zhou ◽  
Bao Yi Wang
Keyword(s):  
Fuel Consumption ◽  
Control Strategy ◽  
Catalytic Reduction ◽  
Water Solution ◽  
Open Loop ◽  
Loop Control ◽  
Consumption Ratio ◽  
Future Emission ◽  
System Configurations ◽  
Scr System

In order to fulfill future emission standards for middle and heavy-duty vehicles like state Ⅳ and Ⅴ, advanced measures on exhaust gas and engine functionality are required. Selective Catalytic Reduction (SCR) technology is the unique technology currently which can improve the emission and reduce fuel consumption simultaneously. Firstly the reductants and its chemical reactions, SCR system configurations and its working principle and urea dosing control strategy are introduced. Then tests are conducted on a diesel engine with SCR system at bench. The results of ESC cycle show that NOx emission is decreased by more than 67% with the open-loop control strategy. Additionally, the urea and fuel consumption and ammonia leakage have been compared and analyzed respectively, the experiment data indicates that the urea water solution consumption ratio is only 5.7% of fuel for this SCR system, while its average ammonia slip is below 5 ppm.

Structure design and optimization of high heat load absorbers in SSRF front-end

2016 ◽  
Vol 24 (7) ◽  
pp. 1640-1646 ◽  
Author(s):  
李勇军 LI Yong-jun ◽  
张 敏 ZHANG Min ◽  
薛 松 XUE Song ◽  
贾丹丹 JIA Dan-dan ◽  
金利民 JIN Li-min
Keyword(s):  
Heat Load ◽  
High Heat ◽  
Structure Design ◽  
Design And Optimization ◽  
Front End ◽  
High Heat Load

scholarly journals One-Dimensional Gas Flow Analysis of the Intake and Exhaust System of a Single Cylinder Diesel Engine

2020 ◽  
Vol 8 (12) ◽  
pp. 1036
Author(s):  
Kyong-Hyon Kim ◽  
Kyeong-Ju Kong
Keyword(s):  
Diesel Engine ◽  
Gas Flow ◽  
Discharge Coefficient ◽  
Flow Analysis ◽  
Exhaust System ◽  
Maximum Pressure ◽  
Exhaust Pipe ◽  
One Dimensional ◽  
Average Mass ◽  
Bent Pipe

In order to design a diesel engine system and to predict its performance, it is necessary to analyze the gas flow of the intake and exhaust system. Gas flow analysis in a three-dimensional (3D) format needs a high-resolution workstation and an enormous amount of time for analysis. Calculation using the method of characteristics (MOC), which is a gas flow analysis in a one-dimensional (1D) format, has a fast calculation time and can be analyzed with a low-resolution workstation. However, there is a problem with poor accuracy in certain areas. It was assumed that the reason was that 1D could not implement the shape. The error that occurs in the shape of the bent pipe used in the intake and exhaust ports of the diesel engine was analyzed and to find a solution to the low accuracy, the results of the experiment and 1D analysis were compared. The discharge coefficient was calculated using the average mass flow rate, and as a result of applying it, the accuracy was improved for the maximum negative pressure by 0.56–1.93% and the maximum pressure by 3.11–7.86% among the intake pipe pressure results. The difference in phase of the exhaust pipe pressure did not improve. It is considered as a limitation of 1D analysis that does not improve even by applying the discharge coefficient. In the future, we intend to implement a bent pipe that cannot be realized in 1D using a 3D format and to prepare a method to supplement the reliability by using 1D–3D coupling.

Research on Design Reference Period and Structural Design Method

2011 ◽  
Vol 368-373 ◽  
pp. 2364-2368
Author(s):  
Jia Nian He ◽  
Zhan Wang
Keyword(s):  
Structural Design ◽  
Reliability Index ◽  
Design Method ◽  
Structure Design ◽  
Reference Period ◽  
Building Structure ◽  
Safety Factors ◽  
Importance Factor ◽  
Partial Safety Factors

In structure design, for expressions with partial safety factors, partial safety factors and nominal value of loads are calculated based on the presupposition that the design reference period is 50 years. When the design reference period is not 50 years, it would cause unclear reliability of building structure by using expressions with partial safety factors following correlative codes yet. It may lead to hidden dangers in that way. In order to derive expressions with partial safety factors suitable for any design reference period, two useful methods are shown in this paper, modification of partial safety factors and modification of importance factor of structures. From results of analysis, we get the conclusions that it can assure the reliability index of the expression using the method of modification of partial safety factors, and the method of modification of importance factor of structures is very simple, but cannot assure the reliability index of the expression.

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