Simultaneous Optimization of Configuration and Control for a Passive SCR System

2018 ◽  
Author(s):  
Pingen Chen ◽  
Qinghua Lin
Keyword(s):  
Catalytic Reduction ◽  
Simultaneous Optimization ◽  
Computationally Efficient ◽  
System Architectures ◽  
Aftertreatment System ◽  
In Series ◽  
System Configurations ◽  
Scr System ◽  
And Control ◽  
Passive Scr

The configuration and control of aftertreatment systems have a significant impact on their functionalities and emission control performance. The traditional aftertreatment system configurations, i.e., connections from one aftertreatment subsystem to another subsystem in series, are simple but generally do not yield the optimal aftertreatment system performance. New aftertreatment configurations, in conjunction with new engine and aftertreatment control, can significantly improve engine efficiency and emission reduction performance. However, new configuration design requires human intuition and in-depth knowledge of engine and aftertreatment system design and control. The purpose of this study is to develop a general systematic and computationally-efficient method which enables automated and simultaneous optimization of passive selective catalytic reduction (SCR) system architectures and the associated non-uniform cylinder-to-cylinder combustion (NUCCC) controls based on a newly proposed highly reconfigurable passive SCR model structure and integer partition theory. The proposed method is general enough to account for passive SCR systems with two or more TWC stages. We demonstrate through this case study that the optimized passive SCR configuration, in conjunction with the optimized NUCCC control, can reduce the NH3 specific fuel consumption by up to 21.90%.

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.

Adaptive and Efficient Ammonia Storage Distribution Control for a Two-Catalyst Selective Catalytic Reduction System

2011 ◽  
Vol 134 (1) ◽  
Author(s):  
Ming-Feng Hsieh ◽  
Junmin Wang
Keyword(s):  
Catalytic Reduction ◽  
Nox Reduction ◽  
Injection Rate ◽  
Nox Emissions ◽  
System A ◽  
Ammonia Slip ◽  
Ammonia Storage ◽  
In Series ◽  
Storage Distribution ◽  
Scr System

This paper presents an adaptive urea-SCR dosing control design for a two-catalyst SCR system. A novel SCR ammonia storage distribution control (ASDC) approach aiming to simultaneously increase the SCR NOx conversion efficiency and reduce the tailpipe ammonia slip was proposed and experimentally validated. Based on the insight into SCR operational principles, a high ammonia storage level at the upstream part of the catalyst can generally yield a higher NOx reduction efficiency while a low ammonia storage level at the downstream part of the catalyst can reduce the undesired tailpipe ammonia slip. To achieve such an ammonia storage distribution control, a two-catalyst (in series) SCR system with NOx and NH3 sensors was devised. Grounded in a newly developed SCR control-oriented model, an adaptive (with respect to the SCR ammonia storage capacity) controller was designed to control the urea injection rate for achieving different ammonia storages in the two catalysts. Experimental data from a US06 test cycle conducted on a medium-duty Diesel engine system showed that, with the similar total engine-out NOx emissions and NH3 (AdBlue) consumptions, the proposed ASDC strategy simultaneously reduced the tailpipe NOx emissions by 57% and the ammonia slip by 74% in comparison to those from a conventional controller.

Observer-Based Estimation of Diesel Engine Aftertreatment System NO and NO2 Concentrations

2010 ◽  
Author(s):  
Ming-Feng Hsieh ◽  
Junmin Wang
Keyword(s):  
Diesel Engine ◽  
Catalytic Reduction ◽  
Diesel Oxidation Catalyst ◽  
Observer Design ◽  
Oxidation Catalyst ◽  
Particulate Filter ◽  
System Control ◽  
Aftertreatment System ◽  
Current Production ◽  
Scr System

This paper presents an observer design for Diesel engine aftertreatment system NO and NO2 concentrations estimations. NO and NO2 have different reaction characteristics within SCR systems. Current production NOx sensors cannot differentiate NO and NO2. Such an observer thus can be used by selective catalytic reduction (SCR) system control and diagnosis purposes. Diesel oxidation catalyst (DOC) and Diesel particulate filter (DPF) were considered as the catalysts which can affect NO/NO2 fraction of the exhaust gas upstream of the SCR. The observer was designed based on an experimentally-validated control-oriented dynamic model which can accurately represent the NO and NO2 dynamics from engine-out, through DOC, and to DPF. Stability of the observer was theoretically proved through a Lyapunov analysis assisted by insight into the system characteristics. The effectiveness of the observer was shown by comparing the estimated NO and NO2 concentrations with the measured ones by a Horiba emissions measurement system.

Configuration and Control Design for a Passive SCR System With NOx Storage Capability

2018 ◽  
Author(s):  
Qinghua Lin ◽  
Pingen Chen ◽  
Vitaly Y. Prikhodko ◽  
James E. Parks
Keyword(s):  
Catalytic Reduction ◽  
Nox Reduction ◽  
Cost Effective ◽  
Nox Storage ◽  
Lean Burn ◽  
Gasoline Engines ◽  
Generation Cost ◽  
Lean Nox ◽  
Scr System ◽  
Passive Scr

Passive selective catalytic reduction (SCR) systems have been considered as a promising technology for reducing NOx emissions for highly-efficient lean burn gasoline engines. Since passive SCR requires intermittent rich operation for self-generating ammonia (NH3) for NOx reduction in the lean phase, the fuel penalty associated with NH3 generation may be significant. To address this issue, a new prototype passive SCR system with NOx storage capability was recently investigated. The three-way catalyst (TWC) with added NOx storage capability is able to enhance NH3 production rate by utilizing pre-stored NOx and thus reduce the fuel cost related to NH3 production. The main purpose of this study is to reduce the ammonia generation cost by: 1) proposing a new passive SCR system architecture that includes two TWC stages; and 2) developing and optimizing a novel non-uniform cylinder-to-cylinder combustion (NUCCC) control. Optimization results based on the experimental data from a physical engine platform, demonstrate that the new passive SCR system (with NOx storage components on TWCs), in conjunction with optimized NUCCC control, is capable of reducing ammonia specific fuel consumption (ASFC) by 30.2%, when compared to a uniform cylinder-to-cylinder combustion (UCCC)-controlled baseline passive SCR system. Such a novel NUCCC control and innovative passive SCR configuration, will be very instrumental in creating cost-effective lean NOx emission control solutions for lean-burn engines in the future.

Modeling and Control of an SCR System

2004 ◽  
Vol 37 (22) ◽  
pp. 355-360
Author(s):  
C.M. Schär ◽  
C.H. Onder ◽  
H.P. Geering
Keyword(s):  
Modeling And Control ◽  
Scr System ◽  
And Control

Modeling, Actuation, and Control of an Active Fluid Vibration Isolator

1997 ◽  
Vol 119 (1) ◽  
pp. 52-59 ◽  
Author(s):  
M. J. Panza ◽  
D. P. McGuire ◽  
P. J. Jones
Keyword(s):  
Electrical Power ◽  
Fluid Pressure ◽  
Space Representation ◽  
Vibration Isolator ◽  
Mass System ◽  
Integral Control ◽  
Active Fluid ◽  
State Space Representation ◽  
In Series ◽  
And Control

An integrated mathematical model for the dynamics, actuation, and control of an active fluid/elastomeric tuned vibration isolator in a two mass system is presented. The derivation is based on the application of physical principles for mechanics, fluid continuity, and electromagnetic circuits. Improvement of the passive isolator performance is obtained with a feedback scheme consisting of a frequency shaped notch compensator in series with integral control of output acceleration and combined with proportional control of the fluid pressure in the isolator. The control is applied via an electromagnetic actuator for excitation of the fluid in the track connecting the two pressure chambers of the isolator. Closed loop system equations are transformed to a nondimensional state space representation and a key dimensionless parameter for isolator-actuator interaction is defined. A numerical example is presented to show the effect of actuator parameter selection on system damping, the performance improvement of the active over the passive isolator, the robustness of the control scheme to parameter variation, and the electrical power requirements for the actuator.

Dynamics and Control of Dual-Hoist Cranes Moving Triangular Payloads

2014 ◽  
Author(s):  
Alexander S. Miller ◽  
Padma Sarvepalli ◽  
William Singhose
Keyword(s):  
Dynamic Response ◽  
Dynamic Behavior ◽  
Bridge Crane ◽  
Response Characteristics ◽  
Dynamics And Control ◽  
System Configurations ◽  
And Control

Certain heavy-lifting applications require the coordinated movement of multiple cranes. Such tasks dramatically increase the complexity of crane operation, especially when the payload has a non-uniform shape. This paper studies the dynamic behavior of a dual-hoist bridge crane moving triangular payloads. Simulations and experiments are used to develop an understanding of the dynamic response of the system. Various inputs and system configurations are analyzed, and important response characteristics are highlighted.

Noise source analysis and control of two axial-flow cooling fans in series

2016 ◽  
Vol 64 (5) ◽  
pp. 677-687 ◽  
Author(s):  
Chen Wang ◽  
Weihao Zhang ◽  
Lixi Huang
Keyword(s):  
Noise Source ◽  
Axial Flow ◽  
Source Analysis ◽  
Cooling Fans ◽  
In Series ◽  
And Control
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