scholarly journals Accelerated performance and durability test of the exhaust aftertreatment system by contaminated biodiesel

2017 ◽  
Vol 18 (10) ◽  
pp. 1067-1076 ◽  
Author(s):  
Jörg Schröder ◽  
Franziska Hartmann ◽  
Robert Eschrich ◽  
Denis Worch ◽  
Jürgen Böhm ◽  
...  
Keyword(s):  
Selective Catalytic Reduction ◽  
Alternative Fuels ◽  
Test Bench ◽  
Catalytic Reduction ◽  
Diesel Oxidation Catalyst ◽  
Oxidation Catalyst ◽  
Exhaust Aftertreatment ◽  
Aftertreatment System ◽  
Exhaust Aftertreatment System ◽  
Diesel Oxidation

The consumption of fossil and especially alternative fuels from renewable sources is supposed to rise in the future. Biofuels as well as fossil fuels often contain alkali and alkaline earth metal impurities that are potential poisons for automotive exhaust catalysts. The impact of these contaminations on the long-time performance of the exhaust aftertreatment system is a major concern. However, engine test bench studies consume considerable amounts of fuel, manpower and time. The purpose of this research project was to examine whether accelerated engine tests can be achieved by a modified diesel aftertreatment system in a test bench and contamination of biodiesel with known amounts of elements potentially poisoning automotive catalysts. A variety of potentially harmful elements (sodium (Na), potassium (K), calcium (Ca), magnesium (Mg), sulfur (S) and phosphorous (P)) were added all at once to enhance the contamination level in biodiesel. A diesel oxidation catalyst and a catalyst for selective catalytic reduction reaction were placed in a stream of exhaust gas generated with a single cylinder engine. For reference purposes, a second test series was performed with a commercially available biodiesel. Catalysts were analyzed post-mortem using a bench flow reactor and X-ray fluorescence regarding their activity and deposition of the harmful elements. For both diesel oxidation catalyst and selective catalytic reduction catalysts, significant deactivation and decrease in conversion rates could be proven. For diesel oxidation catalyst, linear correlations between mass fractions of added elements and aging time were observed.

NO and NO2 Concentration Modeling and Observer-Based Estimation Across a Diesel Engine Aftertreatment System

2011 ◽  
Vol 133 (4) ◽  
Author(s):  
Ming-Feng Hsieh ◽  
Junmin Wang
Keyword(s):  
Diesel Engine ◽  
Catalytic Reduction ◽  
Diesel Oxidation Catalyst ◽  
Equation Model ◽  
Oxidation Catalyst ◽  
Particulate Filter ◽  
Exhaust Gas ◽  
Aftertreatment System ◽  
Stirred Tank Reactors ◽  
Aftertreatment Systems

This paper presents an experimentally validated control-oriented model and an observer for diesel oxidation catalyst (DOC)-diesel particulate filter (DPF) system in the context of exhaust gas NO and NO2 concentration estimations. NO and NO2 have different reaction characteristics within DPF and selective catalytic reduction (SCR) systems, two most promising diesel engine aftertreatment systems. Although the majority of diesel engine-out NOx emissions is NO, the commonly used DOC located upstream of a DPF and a SCR can convert a considerable amount of NO to NO2. Knowledge of the NO/NO2 ratio in exhaust gas is thus meaningful for the control and diagnosis of DPF and SCR systems. Existing onboard NOx sensors cannot differentiate NO and NO2, and such a sensory deficiency makes separate considerations of NO and NO2 in SCR control design challenging. To tackle this problem, a control-oriented dynamic model, which can capture the main NO and NO2 dynamics from engine-out, through DOC, and to DPF, was developed. Due to the computational limitation concerns, DOC and DPF are assumed to be standard continuously stirred tank reactors in order to obtain a 0D ordinary differential equation model. Based on the model, an observer, with the measurement from a commercially available NOx sensor, was designed to estimate the NO and NO2 concentrations in the exhaust gas along the aftertreatment systems. The stability of the observer was shown through a Lyapunov analysis assisted by insight into the system characteristics. The control-oriented model and the observer were validated with engine experimental data and the measured NO/NO2 concentrations by a Horiba gas analyzer. Experimental results show that the model can accurately predict the main engine-out/DOC/DPF NO/NO2 dynamics very well in semisteady-state tests. For the proposed observer, the predictions converge to the model values and estimate the NO and NO2 concentrations in the aftertreatment system well.

scholarly journals Role of Alternative Fuels on Particulate Matter (PM) Characteristics and Influence of the Diesel Oxidation Catalyst

2015 ◽  
Vol 49 (19) ◽  
pp. 11967-11973 ◽  
Author(s):  
Mohammed A. Fayad ◽  
Jose M. Herreros ◽  
Francisco J. Martos ◽  
Athanasios Tsolakis
Keyword(s):  
Particulate Matter ◽  
Alternative Fuels ◽  
Diesel Oxidation Catalyst ◽  
Oxidation Catalyst ◽  
Diesel Oxidation

scholarly journals Transient response of a large two-stroke marine diesel engine coupled to a selective catalytic reduction exhaust aftertreatment system

2019 ◽  
Author(s):  
Μιχαήλ Φωτεινός
Keyword(s):  
Diesel Engine ◽  
Selective Catalytic Reduction ◽  
Transient Response ◽  
Catalytic Reduction ◽  
Exhaust Aftertreatment ◽  
Marine Diesel Engine ◽  
Variable Geometry ◽  
Aftertreatment System ◽  
Marine Diesel ◽  
Variable Geometry Turbine

Οι μεγάλοι δίχρονοι ναυτικοί κινητήρες diesel χρησιμοποιούνται ως μέσο πρόωσης στην πλειονότητα των ποντοπόρων ναυτικών εφαρμογών. Με στόχο τη μείωση του περιβαλλοντικού αποτυπώματος του θαλάσσιου τομέα, ο Διεθνής Ναυτιλιακός Οργανισμός έχει θεσπίσει κανονισμούς που θέτουν αυστηρά όρια στις εκπεμπόμενες εκπομπές οξειδιών του αζώτου (ΝΟx) από ναυτικούς κινητήρες, γνωστούς και ως κανονισμούς ΙΜΟ Tier III. Η Επιλεκτική Καταλυτική Αναγωγή (Selective Catalytic Reduction, SCR) είναι μια τεχνολογία μετεπεξεργασίας καυσαερίων που επιτρέπει την συμμόρφωση με τα νέα πρότυπα εκπομπών NOx. Λόγω της απαίτησης υψηλών θερμοκρασιών για ομαλή λειτουργία του συστήματος SCR, σε ναυτικές εφαρμογές 2-Χ κινητήρων, το SCR τοποθετείται ανάντη του στροβίλου, δηλαδή μεταξύ του κινητήρα και του υπερπληρωτή (στην πλευρά υψηλής πίεσης του στροβίλου). Αυτό έχει ως αποτέλεσμα την διατάραξη της σύζευξης του κινητήρα και του υπερπληρωτή εισάγοντας προκλήσεις στην μεταβατική λειτουργία του κινητήρα. Λόγω της μεγάλης θερμικής αδράνειας του συστήματος SCR, ο υπερπληρωτής αποκρίνεται σε μία μεταβολή φορτίου του κινητήρα με μία σημαντική χρονική καθυστέρηση, η οποία σε χαμηλό φορτίο του κινητήρα μπορεί να οδηγήσει το σύστημα σε θερμική αστάθεια. Ερευνητές έχουν υπογραμμίσει την ευαισθησία του συστήματος και έχουν προτείνει περίπλοκες και κοστοβόρες λύσεις για να διασφαλίσουν την εύρωστη λειτουργία του, όπως το σύστημα στροβίλου μεταβλητής γεωμετρίας (Variable Geometry Turbine, VTG).Η διατριβή αυτή διερευνά τη μεταβατική απόκριση μεγάλου δίχρονου ναυτικού κινητήρα diesel, χωρίς μεταβλητότητα υπερπληρωτή, συνδεδεμένου με σύστημα απορρύπανσης καυσαερίων SCR. Σκοπός της εργασίας είναι η διερεύνηση της επίδρασης του συστήματος SCR υψηλής πίεσης στην μεταβατική απόκριση του κινητήρα με έμφαση στη λειτουργία σε χαμηλό φορτίο κινητήρα. Λόγω του υψηλού κόστους που εμπεριέχεται στα πειράματα με μεγάλους δίχρονους κινητήρες, η έρευνα διεξήχθη μέσω μοντελοποίησης και προσομοίωσης. Αναπτύχθηκαν μοντέλα μηδενικής διάστασης (zero dimensional models) για την προσομοίωση του κινητήρα πρόωσης και του συστήματος SCR. Το μοντέλο του κινητήρα αναπτύχθηκε χρησιμοποιώντας τον κώδικα προσομοίωσης κινητήρων του Εργαστηρίου Ναυτικής Μηχανολογίας MOTHER και επιβεβαιώθηκε με χρήση διαθέσιμων μετρήσεων από τις δοκιμές αγοράς του κινητήρα (shop trials). Επιπλέον, αναπτύχθηκε ένα μοντέλο για το σύστημα SCR ώστε να ληφθεί υπόψη η θερμοκρασιακή δυναμική του συστήματος. Το μοντέλο SCR επιβεβαιώθηκε μέσω σύγκρισης των αποτελεσμάτων του, με διαθέσιμες μετρήσεις από μία κλίνη δοκιμών ναυτικού κινητήρα με σύστημα SCR. Σε μεταβατικές καταστάσεις φόρτισης, το φορτίο που πρέπει να υπερνικήσει ο κινητήρας, δηλαδή η ροπή της έλικας, δεν είναι γνωστό εκ των προτέρων αλλά είναι προιόν περίπλοκων αλληλεπιδράσεων μεταξύ του κινητήρα, της έλικας και της γάστρας του πλοίου. Προκειμένου να επιτευχθή ακριβής πρόβλεψη του φορτίου του κινητήρα κατά τη διάρκεια των μεταβατικών φαινομένων, μοντέλα για την έλικα και τη γάστρα του πλοίου αναπτύχθηκαν και ενσωματώθηκαν στα μοντέλα γάστρας και έλικας. Το συζευγμένο μοντέλο του συστήματος πρόωσης επικυρώθηκε υπό συνθήκες μεταβατικής φόρτισης χρησιμοποιώντας διαθέσιμα μετρημένα δεδομένα επί πλοίου.Το συνολικό σύστημα προσομοιώθηκε υπό μεταβατική φόρτιση υπό καλές και δυσμενείς καιρικές συνθήκες. Τα αποτελέσματα έδειξαν ότι η μεταβατική απόκριση του κινητήρα επηρεάζεται πράγματι από την παρουσία του συστήματος SCR και το αποτέλεσμα είναι πιο έντονο στην περιοχή χαμηλότερου φορτίου κινητήρα. Ωστόσο, η θερμική αστάθεια του συστήματος μπορεί να αποφευχθεί και το σύστημα είναι σε θέση να λειτουργεί ακόμη και κατά τη λειτουργία σε πολύ χαμηλό φορτίο.

Effects of a zeolite-selective catalytic reduction system on comprehensive emissions from a heavy-duty diesel engine

2018 ◽  
Author(s):  
Z. Gerald Liu ◽  
Devin R. Berg ◽  
James J. Schauer‡
Keyword(s):  
Diesel Engine ◽  
Selective Catalytic Reduction ◽  
Catalytic Reduction ◽  
Oxidation Catalyst ◽  
Heavy Duty ◽  
Aftertreatment System ◽  
Selective Catalytic Reduction System ◽  
Reduction System ◽  
Heavy Duty Diesel Engine ◽  
Heavy Duty Diesel

The effects of a zeolite urea-selective catalytic reduction aftertreatment system on a comprehensive spectrum of chemical species from diesel engine emissions were investigated in the present study. Representative samples were collected with a newly developed source dilution sampling system after an aging process designed to simulate atmospheric dilution and cooling conditions. Samples were analyzed with established procedures and compared between the measurements taken from a baseline heavy-duty diesel engine and also from the same engine equipped with the exhaust aftertreatment system. The results have shown significant reductions for nitrogen oxides, carbon monoxide, total hydrocarbons, polycyclic aromatic hydrocarbons, and organic carbon emissions. Additionally, less significant yet notable reductions were observed for particulate matter mass and metals emissions. Although two ionic compounds, sulfate and nitrate, displayed increased emission levels, the production of new species was not observed with the addition of the zeolite urea-selective catalytic reduction system joined with a downstream oxidation catalyst.

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.

Advanced Aftertreatment System Development for a Locomotive Application

2012 ◽  
Author(s):  
Paul W. Park ◽  
Markus Downey ◽  
David Youngren ◽  
Claus Bruestle
Keyword(s):  
Carbon Monoxide ◽  
Particulate Matter ◽  
Nitrogen Oxides ◽  
Catalytic Reduction ◽  
Nox Reduction ◽  
Diesel Oxidation Catalyst ◽  
Oxidation Catalyst ◽  
Loop Control ◽  
Aftertreatment System ◽  
Close Loop Control

For the first time in the locomotive industry, an advanced exhaust aftertreatment system for a locomotive application was successfully demonstrated to reduce nitrogen oxides from 6.46 g/kW·hr to 1.21g/kWhr to meet the needs of local NOx reduction requirements for non-attainment areas. Five 2,240 kW (3,005 horsepower) PR30C line-haul repowered Progress Rail locomotives were equipped with diesel oxidation catalyst and selective catalytic reduction technologies to accumulate more than 27,000 hours in total in revenue service. Full emissions performance including carbon monoxide, hydrocarbons, nitrogen oxides and particulate matter was conducted at Southwest Research Institute on a regular basis to measure the change of emissions performance for two selected locomotives. The emissions performance of the aftertreatment system did not show any degradation during 3,000 hours operation. After 3,000 hours operation, 0.13 g/kW·hr carbon monoxide (89–91% reduction), 0.027 g/ kW·hr hydrocarbons (91% reduction), 1.08–1.21 g/ kW·hr nitrogen oxides (81–83% reduction) and 0.05–0.08 g/ kW·hr particulate matter (38–58% reduction) were measured on the line-haul cycle. The baseline emissions levels of the engine are within Tier 2 EPA locomotive limits. The newly developed close loop control software successfully controlled targeted nitrogen oxides reduction with minimum ammonia slip during the locomotive emission cycle tests.

Internal Flow Analysis of SCR-Exhaust Aftertreatment System

2014 ◽  
Vol 574 ◽  
pp. 96-102
Author(s):  
Lin Lin Ren ◽  
Wei Ding ◽  
Zhe Zhang ◽  
Tao Chen ◽  
Ming Xin Bi ◽  
...  
Keyword(s):  
Gas Flow ◽  
Catalytic Reduction ◽  
Flow Analysis ◽  
Internal Flow ◽  
Reduction Reaction ◽  
Exhaust Aftertreatment ◽  
Exhaust Pipe ◽  
Aftertreatment System ◽  
Exhaust Aftertreatment System ◽  
Nox Control

Selective Catalytic Reduction system (SCR) has made great contributions to diesel engine NOx control technology. The gas flow condition in exhaust pipe has a great effect on catalytic reduction reaction of SCR, especially the airflow through carriers. In this paper, CFD technology was used to simulate the internal flow field, and analyze the gas flow uniformity, which would give us reasonable suggestions to optimize the structure of SCR-Exhaust aftertreatment system.

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