Integrated Emission Management strategy for cost-optimal engine-aftertreatment operation

A new cost-based control strategy is presented that optimizes engine-aftertreatment performance under all operating conditions. This Integrated Emission Management strategy minimizes fuel consumption within the set emission limits by on-line adjustment of air management based on the actual state of the exhaust gas aftertreatment system. Following a model-based approach, Integrated Emission Management offers a framework for future control strategy development.This approach alleviates calibration complexity, since it allows to make optimal trade-offs in an operational cost sense.The potential of the presented cost-optimal control strategy is demonstrated for a modern heavy-duty Euro VI engine. The studied diesel engine is equipped with cooled EGR, Variable Geometry Turbocharger, and a DPF-SCR aftertreatment system. A simulation study shows that the proposed Integrated Emission Management strategy accomplishes 2% to 3% reduction in fuel consumption and operating costs compared to a baseline strategy. Further potential benefits include reduced heat rejection associated with the EGR system and reduced DPF regeneration frequency

Towards Integrated Powertrain Control : exploiting synergy between a diesel hybrid and aftertreatment system in a distribution truck

With the increasing demands on driveability, fuel efficiency and emissions, it becomes essential to optimize the overall performance of future powertrains. Therefore, a system approach is required. In this study, the Integrated Powertrain Control concept is presented, which exploits the synergy between engine, driveline and aftertreatment system. To illustrate the benefits of this concept, the combination of a diesel engine, hybrid driveline and DPF system is studied for a distribution truck. Focus is on minimizing the required energy and components for DPF regeneration. For electric DPF heating, electric heating for DOC light off, and idle-stop cases, the impact on fuel consumption and on DPF temperature are determined during DPF regeneration. It is shown that the operating envelop of the DPF can be extended, even to idle. © 2008 IEEE

Integrated Energy & Emission Management for Heavy-Duty Diesel Engines with Waste Heat Recovery System

This study presents an integrated energy and emission management strategy for an Euro-VI diesel engine with Waste Heat Recovery (WHR) system. This Integrated Powertrain Control (IPC) strategy optimizes the CO2-NOx trade-off by minimizing the operational costs associated with fuel and AdBlue consumption. The main contribution of this work is that the effect of tailpipe emissions and WHR dynamics are included in the control design. In a simulation study, the potential of this strategy is demonstrated over a World Harmonized transient Cycle. These results are compared with a baseline engine control strategy. This study shows that slow WHR dynamics strongly affect the engine performance: neglecting these dynamics in the control design leads to unacceptable high tailpipe NOx emissions. By applying the IPC strategy, an additional 2.8% CO2 reduction is achieved within the NOx emission limit compared to the baseline strategy

SCR-only concept for heavy-duty Euro-VI applications

To meet Euro VI emission targets for heavy-duty applications, truck manufacturers concentrate on Exhaust Gas Recirculation (EGR) and its combination with urea-based Selective Catalytic Reduction (SCR). TNO developed a concept that opens the route for an alternative solution which relies on SCR as the maintechnology for NOx abatement. This concept offers potential fuel benefits in combination with low impact on engine design and cooling equipment. Together with Haldor Topse, Yara and Grundfos, TNO examined theachievable NOx emission reduction on an engine dynamometer

Cost and fuel efficient SCR-only solution for post-2010 HD emission standards

A promising SCR-only solution is presented to meet post-2010 NOx emission targets for heavy duty applications. The proposed concept is based on an engine from a EURO IV SCR application, which is considered optimal with respect to fuel economy and costs. The addition of advanced SCR after treatment comprising a standard and a close-coupled SCR catalyst offers a feasible emission solution, especially suited for EURO VI. In this paper, results of a simulation study are presented. This study concentrates on optimizing SCR deNOx performance. Simulation results of cold start FTP and WHTC test cycles are presented to demonstrate the potential of the close-coupled SCR concept. Comparison with measured engine out emissions of an EGR engine shows that a close-coupled SCR catalyst potentially has NOx reduction performance as good as EGR. Practical issues regarding the use of an SCR catalyst in closecoupled position will be addressed, as well as engine and exhaust layout. For comparison, the requirements of a US 2010/EURO VI compliant high EGR engine are discussed: base engine design, heat rejection, fuel injection equipment, turbo charging and fuel economy. From this study, it is concluded that the SCR-only approach leads to a less expensive engine design with better fuel economy and lower PM emissions. © 2009 SAE International

Ammonia sensor for closed-loop SCR control

Selective Catalytic Reduction (SCR) is the dominant solution for meeting future NOx reduction regulations for heavy-duty diesel powertrains. SCR systems benefit from closed-loop control if an appropriate exhaust gas sensor were available. An ammonia sensor has recently been developed for use as a feedback element in closed-loop control of urea dosing in a diesel SCR aftertreatment system. Closed-loop control of SCR dosing enables the SCR system to be robust against disturbances and to meet conformity of production (COP) and in-use compliance norms. The ammonia sensor is based on a non-equilibrium electrochemical principle and outputs emf signals. The sensor performs well when tested in a diesel engine exhaust environment and has minimum cross interference with CO, HC, NO, NO2, SO2, H2O and O2. Previous work, done in a simulation environment, demonstrated that an ammonia sensor provides the optimal feedback for urea dosing control algorithms in closed-loop SCR systems. A model-based SCR control strategy deploying an ammonia feedback sensor demonstrated high NOx conversion, low NH3 slip and good robustness against disturbances. In this paper, FTP, ETC and ESC test data will be presented confirming these results. NOx conversions as high as 91% are measured in combination with 30% urea injection error and a 25 ppm NH3 slip constraint. Test results using the Delphi ammonia sensor for control are compared with test results utilizing a commercially available NOx sensor for control

Ammonia sensor for closed-loop SCR control

Selective Catalytic Reduction (SCR) is the dominant solution for meeting future NOx reduction regulations for heavy-duty diesel powertrains. SCR systems benefit from closed-loop control if an appropriate exhaust gas sensor were available. An ammonia sensor has recently been developed for use as a feedback element in closed-loop control of urea dosing in a diesel SCR aftertreatment system. Closed-loop control of SCR dosing enables the SCR system to be robust against disturbances and to meet conformity of production (COP) and in-use compliance norms. The ammonia sensor is based on a non-equilibrium electrochemical principle and outputs emf signals. The sensor performs well when tested in a diesel engine exhaust environment and has minimum cross interference with CO, HC, NO, NO2, SO2, H2O and O2. Previous work, done in a simulation environment, demonstrated that an ammonia sensor provides the optimal feedback for urea dosing control algorithms in closed-loop SCR systems. A model-based SCR control strategy deploying an ammonia feedback sensor demonstrated high NOx conversion, low NH3 slip and good robustness against disturbances. In this paper, FTP, ETC and ESC test data will be presented confirming these results. NOx conversions as high as 91% are measured in combination with 30% urea injection error and a 25 ppm NH3 slip constraint. Test results using the Delphi ammonia sensor for control are compared with test results utilizing a commercially available NOx sensor for control

Biogas composition and engine performance, including database and biogas property model

In order to enable this evaluation of the current biogas quality situation in the EU; results are presented in a biogas database. Furthermore the key gas parameter Sonic Bievo Index (influence on open loop A/F-ratio) is defined and other key gas parameters like the Methane Number (knock resistance) are made available in a biogas calculation tool. Finally the results of the study of the influence of biogas quality on the engine performance of Natural Gas Vehicles (NGV), efficiency and emission are presented

Is closed-loop SCR control required to meet future emission targets?

To meet 2010 emission targets, optimal SCR systemperformance is required. In addition, attention has to bepaid to in-use compliance requirements. Closed-loopcontrol seems an attractive option to meet the formulatedgoals. This study deals with the potential and limitationsof closed-loop SCR control.High NOx conversion in combination with acceptable NH3slip can be realized with an open-loop control strategy.However, closed-loop control is needed to make theSCR system robust for urea dosage inaccuracy, catalystageing and NOx engine-out variations. Then, the systemmeets conformity of production and in-use compliancenorms.To demonstrate the potential of closed-loop SCR control,a NOx sensor based control strategy with cross-sensitivity compensation is compared with an adaptivesurface coverage/NH3 slip control strategy and an open-loop strategy. The adaptive surface coverage/NH3 slipcontrol strategy shows best performance over simulatedESC and ETC cycles.SCR catalyst dynamics, time delay in the urea injectionand maximum NH3 slip targets limit the performance ofclosed-loop SCR control. If new reagent dosage systemsand future catalyst technology are able to relieve theselimitations, closed-loop control has the potential toreduce the calibration effort and to improve the transientcontrol performance