Browse Topic: Diesel particulate filters

Items (400)

Medium/Heavy-Duty E/E Systems Diagnosis Nomenclature

J2403_202008 (Historical)

8/3/2020

This SAE Recommended Practice is applicable to all E/E systems on MD and HD vehicles. The terms defined are largely focused on compression-ignited and spark-ignited engines. Specific applications of this document include diagnostic, service and repair manuals, bulletins and updates, training manuals, repair data bases, under-hood emission labels, and emission certification applications. This document focuses on diagnostic terms, definitions, abbreviations, and acronyms applicable to E/E systems. It also covers mechanical systems which require definition. Nothing in this document should be construed as prohibiting the introduction of a term, abbreviation, or acronym not covered by this document. The use and appropriate updating of this document is strongly encouraged. Certain terms have already been in common use and are readily understood by manufacturers and technicians, but do not follow the methodology of this document. These terms fall into three categories: a Acronyms that do not logically fit the term. b Acronyms existing at the component level (i.e., their terms contain the base word or noun that describes the generic item that is being further defined). c Acronyms for terms that appear to contain the base word, but are frequently used as a modifier to another base word. (This use may possibly be thought of as following the methodology, since the acronym is normally used as a modifier.)

Truck Bus Control and Communications Network Committee

Application Layer - Diagnostics

J1939/73_202006 (Historical)6/9/2020

SAE J1939-73 defines the SAE J1939 messages to accomplish diagnostic services and identifies the diagnostic connector to be used for the vehicle service tool interface. Diagnostic messages (DMs) provide the utility needed when the vehicle is being repaired. Diagnostic messages are also used during vehicle operation by the networked electronic control modules to allow them to report diagnostic information and self-compensate as appropriate, based on information received. Diagnostic messages include services such as periodically broadcasting active diagnostic trouble codes, identifying operator diagnostic lamp status, reading or clearing diagnostic trouble codes, reading or writing control module memory, providing a security function, stopping/starting message broadcasts, reporting diagnostic readiness, monitoring engine parametric data, etc. California-, EPA-, or EU-regulated OBD requirements are satisfied with a subset of the specified connector and the defined messages.

Truck Bus Control and Communications Network Committee

Parametric Representation of the Entire Pressure Drop Evolution during Particulate Filter Loading

2020-01-14334/14/2020

Improved understanding and compact descriptions of the pressure drop evolution of Particulate Filters (both for diesel and gasoline powered vehicles) are always in demand for intelligent implementations of exhaust emission system monitoring and control. In the present paper we revisit the loading process of a particulate filter focusing on a parametric description of the deep bed-to-cake transition in the light of recent progress in the understanding of soot deposit structure, growth dynamics and evolution. Combining experimental data, simulation models and information theoretic concepts we provide a closed-form representation of the entire evolution of pressure drop (from the initial clean state up to the evolving linear cake growth regime) parameterized in terms of the physical parameters of the system (filter and particle structure/geometry and flow properties). The representation is shown to be in excellent agreement with the available experimental data and it opens the door for improved on-board monitoring/control of particulate filter systems.

Konstandopoulos, Athanasios G., Metallinou, Rozina

Analysis of TWC Characteristics in a Euro6 Gasoline Light Duty Vehicle

2019-24-01629/9/2019

A Euro6 gasoline light duty vehicle has been tested at the engine dynamometer and the emissions have been analyzed upstream and downstream the Three-Way-Catalyst (TWC) during a WLTC cycle. Catalyst simulations have been used for assessing the processes inside the catalytic converter using a reaction scheme based on 19 brutto reactions (direct oxidation and reduction, selective catalytic reductions with CO, C3H6 and H2, steam reforming, water-gas shift and bulk ceria as well as surface ceria reactions). The reactions have been parameterized in order to best approximate the measurements. Based on the reactions taken into account, the real vehicle emissions can be predicted with good accuracy. The simulations show that the cycle emissions comprise mainly the cold start contribution as well as discrete emission break-through events during transients. During cold start no reactions are evident in the catalyst before the temperature of the gas entering the catalyst reaches 270°C. Following the light-off, prevailing reactions are direct oxidation as well as surface ceria reactions for CO and THC. NO reduction during cold start is due to reaction with CO as well as due to surface ceria. During warm engine operation, CO break-throughs during transients are mainly due to lack of oxygen following short periods where the engine lambda drops below one and most of surface and bulk CeO2 has reacted to surface and bulk Ce2O3. Moreover in such incidents ceria is reacting with THC forming additional CO. THC break-throughs during transients are mostly simultaneous with CO peaks and are also due to lack of oxygen and depleted CeO2. NO transient break-throughs occur when engine-out NO sharply increases, and the reactions with CO and ceria are not sufficient. Further analysis focused in highlighting the effects of variations of Lambda and precious metal content on reaction emissions and mechanisms.

Papetti, Viola, Dimopoulos Eggenschwiler, Panayotis, Emmanouil, Vasiliki, Koltsakis, Grigorios

ELECTRIC MACHINES find their niche

19TOFHP08_018/1/2019

Smaller machines working in cities are particularly ripe for electrification, but most off-highway applications will retain the internal-combustion engine. Many players in the off-highway market are announcing electrification efforts. But why? To date, global regulatory programs have spurred off-highway technological innovations, to improve fuel economy and reduce criteria pollutants. Think U.S. Tier 4 final, Euro Stage V and other global regulations. There's more to it now.

Deposit Reduction in SCR Aftertreatment Systems by Addition of Ti-Based Coordination Complex to UWS

2019-01-03134/2/2019

Formation of urea-derived deposits in selective catalytic reduction (SCR) aftertreatment systems continues to be problematic at temperatures at and below 215 °C. Several consequences of deposit formation include: NOx and NH3 slip, exhaust flow maldistribution, increased engine backpressure, and corrosion of aftertreatment components. Numerous methods have been developed to reduce deposit formation, but to date, there has been no solution for continuous low-temperature dosing of Urea-Water Solution (UWS). This manuscript presents a novel methodology for reducing low-temperature deposit formation in SCR aftertreatment systems. The methodology described herein involves incorporation and dissolution of an HNCO hydrolysis catalyst directly into the UWS. HNCO is a transient species formed by the thermolysis of urea upon injection of UWS into the aftertreatment system. Ideally HNCO undergoes hydrolysis to form NH3 and CO2, but under certain conditions HNCO may polymerize or react with other constituents in the exhaust. Reaction of HNCO with species other than water generally results in the formation of deposits in the aftertreatment system. Addition of an HNCO hydrolysis catalyst directly into the UWS provides maximum contact between catalyst and substrate, thereby improving deposit reduction efficacy. This method of reducing deposits has been shown to reduce deposits by 89% at a 215 °C operating condition.

Hartley, Ryan, Henry, Cary, Eakle, Scott, Tonzetich, Zachary

A 1D Real-Time Engine Manifold Gas Dynamics Model Using Orthogonal Collocation Coupled with the Method of Characteristics

2019-01-01904/2/2019

In this paper, a new solution method is presented to study the effect of wave propagation in engine manifolds, which includes solving one-dimensional models for compressible flow of air. Velocity, pressure, and density profiles are found by solving a system of non-linear Partial Differential Equations (PDEs) in space and time derived from Euler’s equations. The 1D model includes frictional losses, area change, and heat transfer. The solution is traditionally found by utilizing the Method of Characteristics and applying finite difference solutions to the resulting system of ordinary differential equations (ODEs) over a discretized grid. In this work, orthogonal collocation is used to solve the system of ODEs that is defined along the characteristic curves. Orthogonal polynomials are utilized to approximate velocity, pressure, sound speed, and the characteristic curves along which the system of PDEs reduce to a system of ODEs. The approximation polynomials are defined over the whole manifold domain, transforming Euler’s equations into a system of ODEs that can be solved using a generic ODE solver. This reduction is done symbolically using a computer algebra system (Maple). The method results in a system of ODEs that has a higher spatial order along the whole space compared to methods based on finite differences, reducing the number of nodes required to find an acceptable solution that captures the state dynamics at different locations inside the manifold in real time. The proposed model is compared against the Method of Characteristics (MOC) that is used as a reference model; this comparison includes the states at the inlet, outlet, and midpoint. In summary, a high order method that can calculate solutions of the 1D manifold model equations is developed by finding the respective polynomial approximations along the 1D space and solving the resultant system using a generic solver in real time.

Keblawi, Amer, McPhee, John

Development and Experimental Validation of a Control Oriented Model of a Catalytic DPF

2019-01-09854/2/2019

1 The wall-flow Diesel Particulate Filter (DPF) is currently the most common after-treatment system used to meet the particulate emissions regulations for automotive engines. Today’s technology shows the best balance between filtration efficiency and back-pressure in the engine exhaust pipe. During the accumulation phase the pressure drop across the filter increases, thus requiring periodic regeneration of the DPF through after and post fuel injection strategies. This paper deals with the development of a control oriented model of a catalytic silicon carbide (SiC) wall flow DPFs with CuFe2O4 loading for automotive Diesel engines. The model is intended to be used for the real-time management of the regeneration process, depending on back-pressure and thermal state. In order to ensure suitable computational demand and to realize emissions control and fuel economy objectives, the 0-D model has been developed with the aim of investigating the essential behavior of the system, such as the chemical kinetic of filtered soot oxidation, the thermal and backpressure dynamics along accumulation and regeneration processes. Parameters identification and model validation have been performed vs. experimental data measured on the engine test bench at the exhaust of a EURO 5 light-duty Diesel engine, in different operating conditions. During the accumulation process, engine speed, load and rail pressure are controlled to ensure several levels of trapped soot; on the other hand, the injections pattern, which directly affects the DPF inlet temperature, is handled during regeneration tests. The results show that the model simulates the thermal dynamics and the pressure drop across the filter with good accuracy.

D'Aniello, Federica, Rossomando, Bruno, Arsie, Ivan, Pianese, Cesare

Laboratory Experiments Using a 2007 Toyota Auris Event Data Recorder and Additional Data from CAN Bus

2019-01-06354/2/2019

An experimental campaign based on the harness and Event Data Recorder (EDR) of a production vehicle (Toyota Auris 2007, Generation 02EDR) was setup for laboratory experiments. The experiments involved triggering non-deployment events in the EDR by hitting the Airbag Control Module (ACM) with a pendulum style impactor with different pendulum weight, in frontal and rear directions and at different initial angles. The ACM was hit in three different conditions: ACM fixed, ACM free to move and ACM launched towards impactor. The wheel speed sensors were emulated with the same 7/14 mA pulses such that the vehicle was simulated to be moving with a ramping up and down speed during the impact. This was done such that the EDR data has vehicle speed in both its pre and post-crash data. The Bosch Crash Data Retrieval (CDR) tool was used to download the EDR data. Data from these experiments is shown and discussed. An in-house built sniffer was utilized to filter and store the relevant CAN bus data. Such data provides additional information such as the four wheel speeds rather than just one vehicle speed available in the EDR data and at a much faster data rate. It was noted that the vehicle speed is the average of the front wheel speeds even if the front wheel speeds are very different from each other (indicating loss of traction with ground or slip/skid).

Tabone, Miguel, Azzopardi, Jean Paul, Farrugia, Mario, Farrugia, Michael

Experimental and Computational Study of DOC on CSF for Heavy Duty Diesel Applications

2019-01-05864/2/2019

For diesel exhaust aftertreatment applications with space limitations, as well as to move the selective catalytic reduction system (SCR) to a warmer location closer to the engine, DOC on CSF technology can be used. This technology combines the diesel oxidation catalyst (DOC) and catalyzed soot filter (CSF) functionalities in one component, thereby enabling volume reduction. DOC on CSF maintains the abatement of hydrocarbon (HC), carbon monoxide (CO), and particulate matter (PM), and the oxidation of nitric oxide (NO) to nitrogen dioxide (NO2) for passive soot oxidation and fast SCR reaction of NOx on a downstream SCR catalyst. In this study, the performance of DOC on CSF was compared to a DOC + bare diesel particulate filter (DPF) and a DOC + CSF system, to understand the performance benefits and challenges. All the components were optimized individually for their respective functions. The DOC on CSF was optimized for NO oxidation and passive soot oxidation performance. Experimental data and simulations were used to understand the underlying mechanisms in the DOC on CSF technology. Steady state HC oxidation under active regeneration conditions showed a benefit for DOC on CSF compared to the DOC + DPF system. The soot oxidation characteristics of the DOC on CSF were evaluated in comparison to a DPF or CSF downstream of a DOC under passive and active soot oxidation conditions. In addition, the contribution of NO2 generated within the filter on the soot oxidation was assessed. The passive soot oxidation characteristics of a DOC on CSF were found to be similar, or better, compared to DOC + DPF and DOC + CSF under certain conditions. The active regeneration efficiency was lower for the DOC on CSF due to the gradual increase in temperature along the length of the part during fuel injection. This work demonstrates the differences between the DOC on CSF and DOC + bare/coated DPF systems, thus enabling a better understanding of the performance of DOC on CSF to current applications.

Sethuraman, Sharan, Sitamraju, Siddarth, Lopez-De Jesus, Yaritza M, Markatou, Penelope

Review of Vehicle Engine Efficiency and Emissions

2019-01-03144/2/2019

This review paper covers major regulatory and technology developments in 2018 pertinent to tailpipe emissions of greenhouse gases and criteria pollutants. Europe has proposed ambitious reductions in CO2 limits for both light- and heavy-duty sectors. The challenge is compounded with changing measurement norms and a significant shift away from fuel efficient diesels in the light-duty (LD) space. Both incremental and step changes are being made to advance internal combustion. New studies show that in-use NOx emissions from diesels can be much lower than required by the Euro 6 regulation. Discussions have already started on Euro 7 regulations, and the leading regulatory concepts and proposed technical solutions are provided. In the heavy-duty (HD) sector, the progress is outlined in improving engine and vehicle fuel efficiency through the US Department of Energy’s (DOE’s) SuperTruck II program and other representative studies. Common approaches among the participants include hybridization, waste heat recovery, and both open- and closed cycle incremental improvements. Emissions control focus is on evaluating pathways to achieve California’s contemplated low-NOx standards, recently also supported by the US EPA through the Cleaner Trucks Initiative. The challenge is to reduce cold start and low load emissions, requiring innovative engine and after-treatment system solutions. Leading concepts include close-coupled SCR (selective catalytic reduction), use of passive NOx adsorbers, integration of SCR (selective catalytic reduction) on DPFs (diesel particulate filters), low temperature urea or ammonia injection, dual SCR, and active and passive thermal management to raise exhaust temperatures. Work is also underway on a new low load certification cycle. Continued advancement is made on after-treatment components. Aged three-way catalysts (TWCs) and diesel oxidation catalysts (DOCs) are nearing 90% conversion at 150 °C. SCR catalysts continue to improve both their low temperature conversion as well as high temperature durability. Particulate regulations in Europe, China and India are leading to widespread adoption of gasoline particulate filters (GPFs). Lean burn gasoline engines can offer significant fuel economy benefits. NOx control is a challenge, and passive SCR systems and new catalysts are proposed.

Smart DPF Regenerations - A Case Study of a Connected Powertrain Function

2019-01-03164/2/2019

The availability of connectivity and autonomy enabled resources, within the automotive sector, has primarily been considered for driver assist technologies and for extending the levels of vehicle autonomy. It is not a stretch to imagine that the additional information, available from connectivity and autonomy, may also be useful in further improving powertrain functions. Critical powertrain subsystems that must operate with limited or uncertain knowledge of their environment stand to benefit from such new information sources. Unfortunately, the adoption of this new information resource has been slow within the powertrain community and has typically been limited to the obvious problem choices such as battery charge management for electric vehicles and efforts related to fuel economy benefits from adaptive/coordinated cruise control. In this paper we discuss the application of connectivity resources in the management of an aftertreatment sub-system, the Diesel Particulate Filter (DPF). Standard DPF regenerations are scheduled on an inferred soot load based on indirect indicators of system state, such as exhaust gas flow rate and pressure drop across the DPF and/or empirical models of engine out soot. Soot load estimation approaches such as these are necessary since a reliable method of a direct soot load measurement in a DPF is currently not available. In addition to model uncertainty it is also well known that regeneration control also suffers from uncertainty related to the drive routes, driver behavior, and traffic flow over the driven routes. These uncertainties force a conservative regeneration scheme, that does not fully exploit the soot trapping capacity of the DPF. This makes it difficult to guarantee any measure of uniform optimality over all vehicles. It is evident, however, that by leveraging information that allows a reduction in driver and traffic related uncertainties it may be possible to better schedule DPF regenerations and achieve some degree of performance benefit related to the overall efficiency of the regeneration process over the life of the vehicle. In this paper we present some initial results from such an effort that leverages cloud based real time traffic flow information from a traffic provider in making smart decisions related to the soot management over a DPF.

Hopka, Michael, Upadhyay, Devesh, Van Nieuwstadt, Michiel

Application Layer - Diagnostics

J1939/73_201901 (Historical)1/31/2019

SAE J1939-73 Diagnostics Application Layer defines the SAE J1939 messages to accomplish diagnostic services and identifies the diagnostic connector to be used for the vehicle service tool interface. Diagnostic messages (DMs) provide the utility needed when the vehicle is being repaired. Diagnostic messages are also used during vehicle operation by the networked electronic control modules to allow them to report diagnostic information and self-compensate as appropriate, based on information received. Diagnostic messages include services such as periodically broadcasting active diagnostic trouble codes, identifying operator diagnostic lamp status, reading or clearing diagnostic trouble codes, reading or writing control module memory, providing a security function, stopping/starting message broadcasts, reporting diagnostic readiness, monitoring engine parametric data, etc. California-, EPA-, or EU-regulated OBD requirements are satisfied with a subset of the specified connector and the defined messages.

Truck Bus Control and Communications Network Committee

Modeling and Experimentation of GDI-Sized Particulate Filtration and Pressure-Drop Behavior in Uncoated Commercial DPF Substrates

2019-01-00521/15/2019

Gasoline Direct Injection (GDI) is known to produce lower concentrations of smaller particulate matter (PM) compared to diesel combustion [1]. The lower concentration results in the absence of soot-cake formation on the filter channel wall and therefore filtration behavior deviates from the expected diesel particulate filter (DPF) performance. Therefore, studies of cake-less filtration regimes for smaller sized particulates is of interest for GDI PM mitigation. This work investigates the filtration efficiency of laboratory-generated particulates, representative of GDI-sized PM, in uncoated, commercial DPF cordierite substrates of varying porosities. Size-dependent particulate concentrations were measured using a Scanning Mobility Particle Sizer (SMPS), both upstream and downstream of the filters. By comparing these measured concentrations, the particle size-dependent filtration efficiency of filter samples was calculated. To predict filtration efficiency for these non-loaded particulate traps, the Opris and Johnson flow field model was updated to include sedimentation and thermophoretic terms and with soot-cake related filtration approximations removed. Experimental results showed excellent agreement with model predictions. Our study demonstrated that current DPFs are insufficient for deployment on GDI vehicles due to their low filtration efficiency for GDI-sized particles. GPFs (gasoline particulate filters) are essential and the newly developed filtration model can serve well to facilitate their design.

Sheppard, Jessica, Yang, Pengze, Strzelec, Andrea

Assessing the Impact of FAME and Diesel Fuel Composition on Stability and Vehicle Filter Blocking

2019-01-00491/15/2019

In recent years, there has been an impetus in the automotive industry to develop newer diesel injection systems with a view to reducing fuel consumption and emissions. This development has led to hardware capable of higher pressures, typically up to 2500 bar. An increase in pressure will result in a corresponding increase in fuel temperature after compression with studies showing changes in fuel temperatures of up to 150 °C in 1000-2500 bar injection systems. Until recently, the addition of Fatty Acid Methyl Esters, FAME, to diesel had been blamed for a number of fuel system durability issues such as injector deposits and fuel filter blocking. Despite a growing acceptance within the automotive and petrochemical industries that FAME is not solely to blame for diesel instability, there is a lack of published literature in the area, with many studies still focusing on FAME oxidation to explain deposit formation and hardware durability. The majority of studies into diesel degradation are conducted under non-representative laboratory conditions, or are extrapolated from the deposits found in filters from vehicles with failed injectors. In this study, the cause of this degradation was investigated by using a novel High Pressure Common Rail (HPCR) non-firing rig designed to mimic a diesel common rail system, simulating realistic, albeit accelerated, operating conditions. The degree of deposition on the system fuel filter was monitored, for both petroleum diesel (B0), RF79 (B0), Bx (where x is percentage volume/volume of FAME) and surrogate diesel fuel components. A systematic study of synthetic surrogates demonstrated that, as well as FAME, any base fuel component, under sufficiently high pressures and temperatures experienced in the HPCR are prone to degradation irrespective of the concentration of the component in the original fuel. The most unstable component acts as the instigator, thus promoting fuel oxidation. The other components in the fuel such as FAME, aromatic and cycloalkane portions will also oxidise and eventually polymerise to form solids blocking the filter. This also demonstrates that while a large body of work on the oxidative instability of biodiesel in the chemical laboratory is indicative of instability this does not mimic what is seen under more realistic vehicle conditions and the focus on FAME instability is misleading.

Gopalan, Kesavan, Chuck, Christopher J., Roy-Smith, Christopher, Bannister, Christopher D.

Medium/Heavy-Duty E/E Systems Diagnosis Nomenclature

J2403_201812 (Historical)12/19/2018

This SAE Recommended Practice is applicable to all E/E systems on MD and HD vehicles. The terms defined are largely focused on compression-ignited and spark-ignited engines. Specific applications of this document include diagnostic, service and repair manuals, bulletins and updates, training manuals, repair data bases, under-hood emission labels, and emission certification applications. This document focuses on diagnostic terms, definitions, abbreviations, and acronyms applicable to E/E systems. It also covers mechanical systems which require definition. Nothing in this document should be construed as prohibiting the introduction of a term, abbreviation, or acronym not covered by this document. The use and appropriate updating of this document is strongly encouraged. Certain terms have already been in common use and are readily understood by manufacturers and technicians, but do not follow the methodology of this document. These terms fall into three categories: a Acronyms that do not logically fit the term. b Acronyms existing at the component level (i.e., their terms contain the base word or noun that describes the generic item that is being further defined). c Acronyms for terms that appear to contain the base word, but are frequently used as a modifier to another base word. (This use may possibly be thought of as following the methodology, since the acronym is normally used as a modifier.)

Truck Bus Control and Communications Network Committee

Study on the Prevention of Face-Plugging of Diesel Oxidation Catalyst (DOC)

2018-32-006910/30/2018

In order to meet the reinforcement of worldwide environmental regulations, latest diesel engines for industrial machinery are required to reduce the emission of harmful gases such as carbon monoxide (CO), hydrocarbon (HC) and nitrogen oxide (NOx), and particulate matter (PM). For this reason, some of the diesel engines are equipped with exhaust gas treatment devices such as diesel particulate filter (DPF), diesel oxidation catalyst (DOC) and selective catalytic reduction (SCR) catalyst. However, applications of such industrial diesel engines bring about excessive back pressure increase and deterioration in the performance of the catalysts when continuous operation is performed at low load conditions: soot accumulates on the inlet faces of DOC and DPF, causing face plugging issues. To resolve this issue, it is necessary for the system to be equipped with certain additional devices to raise an exhaust gas temperature to a high level enough to burn out the soot [1]. In this research, in order to solve the face plugging at the inlet of DOC without using such an additional equipment, we studied the cause of the face plugging of DOC. First, in order to estimate the cause of face plugging, we grasped the engine operating conditions leading to the face plugging and analyzed the soot/coke deposits accumulating on the inlet face of DOC under specific conditions. Next, in order to identify the origin of the face plugging causative deposits, we performed a component analysis of an engine exhaust gas and also conducted catalytic reaction experiments using a model exhaust gas. Then, verification experiments using an engine were carried out. As a result, we found that the production of less combustible HC by incomplete catalytic oxidation is one of the factors of the plugging problem of DOC.

Nakano, Kota, Okano, Hiroaki, Inoue, Katsushi, Obuchi, Akira

Diesel CAI Combustion in Uniflow Scavenging 2-Stroke Engine Provided with Port Fuel Injection Device

2018-32-001510/30/2018

We studied a simple and cost effective controlled auto ignition (CAI) combustion engine in order to achieve simultaneous reduction of NOx and soot, which are issues in diffusion combustion. The engine type was a uniflow scavenging 2-stroke engine, and the fuel used was diesel, as is common in diesel engines. We examined the position of the injector that effectively forms the premixture and realized stable operation with diesel fuel by the low pressure fuel injection device for port fuel injection (PFI), and it was found that the CAI combustion ignition timing can be controlled through setting the air/fuel ratio that obtains the optimal ignition timing per operation conditions. As a result of verifying the potential of this engine, it was confirmed that the regulation emissions level required for joint use of common rail fuel injection system (CRS), exhaust gas recirculation (EGR), diesel particulate filter (DPF), diesel oxidation catalyst (DOC), etc. in nonroad compression ignition (NRCI) engines can be achieved only by exhaust aftertreatment with a DOC. Furthermore, it was confirmed that break mean effective pressure (BMEP) equivalent to 4-stroke is about the same level as naturally aspirated NRCI engines and specific fuel consumption (SFC) has the potential to be about the same level or lower than NRCI engines with displacement of less than 2000 cm3.

Kurata, Mashu, Yamada, Yoshikazu

Emissions reductions continue to disrupt CV industry

18TOFHP10_0510/1/2018

As the automotive and commercial vehicle (CV) industries expand from being dominated by a single powertrain to a multitude of power and fuel options, disruption is propelling change to the entire mobility ecosystem. The emissions field continues to see this change as regulations further reduce output levels on a global scale. The California Air Resources Board (CARB) remains a leading organization of reducing emission levels in the U.S. Based on the Environmental Protection Agency's (EPA) reports of excessive ozone levels in the state, CARB is seeking to reduce NOx output by 80%. As further recognition of this issue, the Governor of California recently signed Senate Bill 100 to make the state's energy production 60% renewable by 2030 and 100% renewable by 2045.

Polycyclic Aromatic Hydrocarbons in Diesel Engine Exhaust Both with and without Aftertreatment

2018-01-18129/10/2018

Since the conception of the internal combustion engine, smoky and ill-smelling exhaust was prevalent. Over the last century, significant improvements have been made in improving combustion and in treating the exhaust to reduce these effects. One group of compounds typically found in exhaust, polycyclic aromatic hydrocarbons (PAH), usually occurs at very low concentrations in diesel engine exhaust. Some of these compounds are considered carcinogenic, and most are considered hazardous air pollutants (HAP). Many methods have been developed for sampling, handling, and analyzing PAH. For this study, an improved method for dilute exhaust sampling was selected for sampling the PAH in diesel engine exhaust. This sampling method was used during transient engine operation both with and without aftertreatment to show the effect of aftertreatment. A total of 23 different PAH were measured using a 2012 medium-duty diesel engine equipped with a diesel oxidation catalyst (DOC), a diesel particulate filter (DPF), and a selective catalytic reduction (SCR) catalyst in series. The PAH were then analyzed by gas chromatography/mass (GC/MS) spectrometry to determine the individual concentrations for engine-out (without aftertreatment) and aftertreatment-out emissions. Concentrations for the engine-out PAH were significantly higher than when the aftertreatment was present. PAH in the exhaust were then compared to the PAH in the fuel.

Fanick, E. Robert, Kroll, Svitlana

Effects of Hot and Cooled EGR for HC Reduction in a Dual-Fuel Premixed Charge Compression Ignition Engine

2018-01-17309/10/2018

Most internal combustion engine makers have adopted after-treatment systems, such as selective catalytic reduction (SCR), diesel particulate filter (DPF), and diesel oxidation catalyst (DOC), to meet emission regulations. However, as the emission regulations become stricter, the size of the after-treatment systems become larger. This aggravates the price competitiveness of engine systems and causes fuel efficiency to deteriorate due to the increased exhaust pressure. Dual-fuel premixed charge compression ignition (DF-PCCI) combustion, which is one of the advanced combustion technologies, makes it possible to reduce nitrogen oxides (NOx) and particulate matter (PM) during the combustion process, while keeping the combustion phase controllability as a conventional diesel combustion (CDC). However, DF-PCCI combustion produces high amounts of hydrocarbon (HC) and carbon monoxide (CO) emissions due to the bulk quenching phenomenon under low load conditions as a huddle of commercialization. In this study, the effects of exhaust gas recirculation (EGR) rate and EGR temperature were investigated to overcome the bulk quenching phenomenon under low load conditions in the DF-PCCI combustion. Natural gas (NG) and diesel were selected for low reactivity fuel (LRF) and high reactivity fuel (HRF) respectively. As experimental results, adopting the high temperature EGR could reduce the HC emission, and improve combustion efficiency (ηc) and fuel conversion efficiency (ηf), while maintaining the NOx and PM emissions under the EU-VI emission regulations. The results suggest that controlling the global equivalence ratio (∅global) and increasing the initial charge temperature by hot-EGR are quite effective way to mitigate the bulk quenching phenomenon and incomplete combustion under low load conditions in the DF-PCCI combustion.

Shim, Eui joon, Park, Hyunwook, Bae, Choongsik

Effects of Soot Deposition on NOx Purification Reaction and Mass Transfer in a SCR/DPF Catalyst

2018-01-17079/10/2018

Experimental studies were carried out to investigate the effect of soot deposition on NOx purification phenomena in an ammonia selective catalytic reduction coated diesel particulate filter (SCR/DPF) catalyst. To study soot deposition effects on the chemical reactions and mass transfer, two types of testing device were used. A synthetic gas bench enabling tests to be conducted with temperature and flow rate ranges relevant to real driving conditions was used to investigate the soot influence on reduction of NOx to N2 (DeNOx). A micro-reactor that removed the effect of soot deposition on mass transfer in the catalyst layer was used to analyze chemical reactions on a soot surface and their interaction with the SCR catalyst. A filter test brick of a Cu-zeolite SCR/DPF catalyst and a powder catalyst were used for the synthetic gas bench and micro-reactor tests, respectively. Engine soot was sampled in all the tests. The synthetic gas bench results showed that soot deposition had a negative impact on NOx conversion performance. The micro-reactor results showed that NOx purification reactions took place simultaneously with side reactions, e.g., NH3 oxidation and NO2 related reactions, even when no SCR catalyst was present. Reactions on the soot surface decreased the NOx purification performance of the SCR catalyst. The influence of soot deposition on the reactivity of side reactions in the filter test brick showed the opposite effect to the powder catalyst: the former effect was intensified as the flow rate was increased. It was concluded that both the effect of reaction on the soot surface and the influence on mass transfer of soot deposition must be considered to describe the internal phenomena of NOx purification in a SCR/DPF catalyst.

Tsukamoto, Yoshihisa, Utaki, Shun, Zhang, Wencong, Fukuma, Takao, Kusaka, Jin

Numerical Analysis on the Potential of Reducing DPF Size Using Low Ash Lubricant Oil

2018-01-17609/10/2018

Diesel particulate filter (DPF) is necessary for diesel engines to meet the increasingly stringent emission regulations. Many studies have demonstrated that the lubricant derived ash has a significant effect on DPF pressure drop and engine fuel economy, and this effect becomes more and more severe with the increasing of operating hours of the DPF because the ash accumulated in the DPF cannot be removed by regeneration. It is reported that most of the DPFs operated with more ash than soot in the filter for more than three quarters of the time during its lifetime [1]. In order to mitigate this problem, the original engine manufacturers (OEM) tend to use an oversized DPF for the engine. However, it will increase the costs of the DPF and reduce the compactness of the engine aftertreatment system. With the development of the lubricant additives technology, some OEMs and lubricant oil manufacturers are concerning that if there is any possibility to reduce DPF size using low ash lubricant oil. In this work, a numerical DPF model was built to estimate the DPF pressure drop at different soot loading and ash loading levels. With the model, the lifetime averaged fuel penalty of the DPFs with different sizes and operating with different ash content lubricant oils were calculated. Based on the calculation results, the potential of reducing DPF size using low ash lubricant oil was analyzed under the same design criteria of engine fuel consumption penalty. The analysis results show that the DPF size can be reduced by about 6% by lowering the lubricant oil ash content from 1.0% to 0.75%, and 14% by lowering from 1.0% to 0.5%. The DPF size can be maximally reduced by lowering the lubricant oil ash content from 1.0% to 0.25%, which can reduce about 22% of the DPF size. While the DPF size can be only reduced by 7% by using no ash lubricant oil because of no “membrane effect” of the ash on the soot depth filtration in the DPF. The role of engine-out particulate matters (PM) emission and DPF regeneration control strategy on this potential was also studied, and the potential is slightly increased when the engine has a higher engine-out PM emission or a DPF regeneration control strategy with ash effects corrections is applied.

Zhang, Jun, Qi, Jinzhu, Shuai, Shi-Jin, Wang, Lei, Liu, Shiyu, Wang, Guoyang, Liu, Fan, Brown, Jason

Comparison of Accelerated Ash Loading Methods for Gasoline Particulate Filters

2018-01-17039/10/2018

Recent legislation enacted for the European Union (EU) and the United States calls for a substantial reduction in particulate mass (and number in the EU) emissions from gasoline spark-ignited vehicles. The most prominent technology being evaluated to reduce particulate emissions from a gasoline vehicle is a wall flow filter known as a gasoline particulate filter (GPF). Similar in nature to a diesel particulate filter (DPF), the GPF will trap and store particulate emissions from the engine, and oxidize said particulate with frequent regeneration events. The GPF will also collect ash particles in the wall flow substrate, which are metallic components that cannot be oxidized into gaseous components. Due to high temperature operation and frequent regeneration of the GPF, the impact of ash on the GPF has the potential to be substantially different from the impact of ash on the DPF. Therefore, traditional accelerated ash loading methods used for DPFs may not be applicable to the GPF technology. This paper summarizes three accelerated ash loading strategies that were evaluated and compared to a field generated component to understand the applicability of the accelerated methods. CT Scan imaging was used to compare each ash loading technique relative to a field generated GPF.

Eakle, Scott, Avery, Stephen, Weber, Phillip, Henry, Cary

Studies on the Influence of Engine Conditions and Different Ash Levels on the Regeneration Behavior of Particulate Filters

2018-01-17049/10/2018

Diesel particulate filters are effective devices to remove particulate matter from the diesel exhaust and to fulfill emission standards. However, the operating behavior is crucially influenced by the characteristics of the deposited and accumulated soot and ash, which is affected by different diesel engine operating parameters. This is especially relevant for the thermal control of the regeneration process that poses a challenge resulting from the lack of knowledge concerning the operation behavior of the filter. Within this study, the regeneration behavior of diesel particulate filters with several age-related states is compared. For that purpose, filters were aged with an accelerated method. These filters were loaded with different steady state conditions at the engine test bench. The subsequent regeneration was applied via post-injection. Therefore, it was possible to investigate the influence of different ash levels on the regeneration behavior of the filter. The results reveal significant differences concerning regeneration behavior of uncoated filters with several ash levels. Characteristic values were used for the evaluation of the regeneration process. The most relevant differences were visible when the filters were loaded with engine operating conditions with small particle agglomerates. These differences particularly include the duration, the temperature levels and temperature gradients inside the filter during the regeneration. Furthermore, the ash level influences the soot distribution and thus, the start of the soot oxidation and the temperature levels. In addition, the mass flow during the loading of the filter plays a significant role for the distribution of the soot and therefore for the regeneration process.

Zöllner, Christian, Brueggemann, Dieter

Impact of SCR Activity on Soot Regeneration and the Converse Effects of Soot Regeneration on SCR Activity on a Vanadia-SCRF®

2018-01-09624/3/2018

The influence of SCR (selective catalytic reduction) activity on soot regeneration was investigated using engine test measurements with and without urea dosing on a vanadia-SCRF®1, also known as a vanadia SCR coated diesel particulate filter (V.SCR-DPF). The extent and rate of passive soot regeneration is significantly reduced in the presence of SCR activity especially at high temperatures (>250 °C). The reduction in soot regeneration is because some of the NO2, which would otherwise react with the soot, is consumed by SCR reactions and consequently the rate of soot regeneration is lower when urea is dosed. The converse effects of soot oxidation on SCR activity were studied separately by analysing steady-state light-off engine measurements with different initial soot loadings on the V.SCR-DPF. The measurements show an increase in NOX conversion with increasing soot loading. This is because the reaction of soot with NO2 results in NO2/NOX ratio becoming closer to the optimal value for SCR activity of 0.5. This observation for these particular engine tests is because the V.SCR-DPF inlet NO2/NOX ratio was greater than 0.5. At low temperatures (<250 °C), NO2 conversion decreases with increasing temperature, which was attributed to the decrease in the net rate of ammonium nitrate formation with increasing temperature in this temperature range, which in turn results in a decrease in NO2 consumption. The impact of ammonium nitrate formation on NO2 conversion was also observed to be correlated to soot loading at these low temperatures. Numerical modelling was also utilised to gain further insights into the influence of soot regeneration on SCR activity and the converse effects of SCR activity on soot regeneration on a V.SCR-DPF. The model captures qualitatively and quantitatively the decrease in soot regeneration rate as a result of NO2 competition between passive soot oxidation and SCR reactions. The model also fairly predicts the enhanced SCR activity for the soot loaded V.SCR-DPF due to alteration of NO2/NOx ratio by passive soot oxidation.

Chigada, Peter I., Ahmadinejad, Mehrdad, Newman, Andrew D., Ng, Alfred Iam Pou, Torbati, Reza, Watling, Timothy C.

A Simulation Study on Particle Motion in Diesel Particulate Filter Based on Microcosmic Channel Model

2018-01-09644/3/2018

As the prime after-treatment device for diesel particulate matter (PM) emission control, Diesel Particulate Filter (DPF) has been widely used for its high particle capture efficiency. In order to study the particle motion and deposition distributions in the DPF inlet channel, a 2-D wall flow DPF microcosmic channel model is built in this paper. The motion trajectories of particles with different sizes are investigated considering the drag force, Brownian motion, gravity and Saffman lift. The effects of the space velocity on particle motion trajectories and deposition distributions inside the inlet channel are evaluated. These results demonstrate that the particle motion trajectories are highly dependent on particle sizes and influenced by the space velocity. The effect of the Brownian motion is obvious for fine particles and suppressed when the space velocity is raised. Moreover, various patterns of particle deposition distributions at the wall surface along the inlet channel are obtained under different particle sizes. The uniformity of particle deposition distributions is closely related to the particle size. With the increase of the particle size, more particles deposit at the rear-part of the inlet channel. Finally, in order to estimate the uniformity magnitude of particle deposition distributions, a uniformity index is proposed and discussed in this paper.

Wu, Yue, Li, Zhijun, shen, Boxi, Kong, Xiangjin, Cao, Lijuan, Zhu, Lingya

Study of the Deep-Bed Filtration Using Pore Filtration Model (PFM)

2018-01-09564/3/2018

To meet stringent emissions regulations, filtration devices are often used in engine exhaust systems to reduce particulate mass (PM) and particulate number (PN). Diesel particulate filters (DPFs) are a well-established means of reducing PM from diesel engines to meet emissions regulations. New emissions regulations will most likely require a similar technology on gasoline engines with direct injection, gasoline particulate filters (GPFs). Due to differences in the exhaust and particulate characteristics, the design and operation of GPFs and DPFs differ. In a DPF filtration is dominated by the buildup of a soot cake. Whereas in a GPF, much of the soot is trapped inside the porous substrate, or filter wall, where deep-bed filtration is dominant. Thus, an accurate model describing the porous filtration properties of GPF substrates is desired. The pore filtration model (PFM) was developed to more accurately model the deep-bed filtration process that occurs in a GPF. This includes changes in the porous material characteristics which impact the filtration efficiency and pressure drop. The PFM model is based on a constricted tube unit collector rather than the traditional spherical unit collector used in DPF models. This geometry more closely represents the pores in a GPF substrate. In addition, it gives additional geometric parameters for representing different types of substrates. Data from a spark-ignition direct-injection (SIDI) engine was used to validate the model. The PFM can capture with high accuracy both the number-based filtration efficiency and pressure drop under various engine operating conditions and for various filter samples. Of the different geometric parameter used in the PFM, it was found the pore throat diameter had the largest effect on the filtration efficiency.

Yang, Yangdongfang, Rutland, Christopher, Rothamer, David

Development of Improved SCRonDPF Design for Future Tighter Regulations and Reduced System Packaging

2018-01-03444/3/2018

With the push towards more stringent on-road US heavy duty diesel regulations (i.e. HD GHG Phase 2 and the proposed ARB 20 mg/bhp-hr NOx), emission system packaging has grown critical while improving fuel economy and NOx emissions. The ARB regulations are expected to be implemented post 2023 while regulation for EU off-road segment will begin from 2019. The regulation, called Stage V, will introduce particle number (PN) regulation requiring EU OEMs to introduce a diesel particulate filter (DPF) while customer demands will require the OEMs to maintain current emission system packaging. A viable market solution to meet these requirements, especially for EU Stage V being implemented first, is a DPF coated with a selective catalyst reduction (SCR) washcoat (i.e. SCRonDPF). With SCRonDPF, a NOx reduction benefit is achieved while maintaining system packaging but, there is an increase in pressure drop due to the higher washcoat loading (WCL) for the SCRonDPF compared to a catalyzed soot filter (CSF). This paper first focuses on a parameter study to develop an improved Cordierite SCRonDPF design to reduce pressure drop while maintaining other key performances. A high porosity material (65%), 12 mil wall thickness (WT), 300 cells per square inch (cpsi) cell density, with a square shaped cell structure (12/300SQ) was used as the baseline. The design parameters evaluated include the pore size distribution (PSD), mean pore size (MPS), cell shape, cell density (CPSI), WT, and washcoat technology. Engine tests conducted were soot loaded pressure drop up to 6 g/L soot loading, active regeneration conducted at 600 °C, passive regeneration conducted at 350 °C, and PN filtration and NOx conversion efficiency performed on the Non-Road Transient Cycle (NRTC). Results from the parameter study show 12 mil/300 cpsi asymmetric (ASY) cell structure with a lower MPS and sharper PSD material, in combination with an improved catalyst, is the optimal SCRonDPF filter design achieving a pressure drop approximately 55% compared to the baseline SCRonDPF filter. The optimized SCRonDPF system pressure drop achieved closer to the production CSF system but still approximately 10% higher.

Taylor, Mychal, Kaneda, Atsushi, Kai, Ryuji, Asako, Tsuyoshi, Miyahara, Yudai, Vogt, Claus, Makino, Mikio, Toyoshima, Tetsuo, Honda, Takahiro

Simultaneous Measurement of Fuel Droplet Deposition Amount and Oil Film Thickness on Spray Impingement Using Double Laser Induced Fluorescence Method

2017-01-237110/8/2017

Diesel Particulate filter (DPF) is installed as after treatment device of exhaust gas in diesel engine, and collects the Particulate Matter (PM). However, as the operation time of engine increases, PM is accumulated in the DPF, resulting in deterioration of PM collection efficiency and increasing in pressure loss. Therefore, Post injection has been attracted attention as DPF regeneration method for burning and removing PM in DPF. However, Post injection causes oil dilution when fuel is injected at the middle to late stage of expansion stroke. Oil dilution are concerned to deteriorate the sliding property of piston and the thermal efficiency. For this reason, it is necessary to elucidate the mechanism and the behavior that spray impinges lubricating oil film. Therefore, in this study, we aimed to construct model of Computational Fluid Dynamics (CFD) that predicts amount of oil dilution which is concern for post injection in diesel engine, with high accuracy. In this report, we constructed Double Laser Induced Fluorescence (DLIF) applying LIF. In the DLIF, two kinds of fluorescent dyes were dissolved to diesel fuel and engine oil respectively, and Ultraviolet (UV) -LED was used as excitation light. Each fluorescence wavelength was spectrally separated at a specific wavelength. DLIF makes it possible to simultaneously and continuously measure fuel film thickness and oil film thickness in the case of diesel spray impinging lubricating oil film. As the result of measurement using DLIF, it was found that a large difference of deposition amount which fuel spray impinges dry wall and lubricating oil film. Due to influence of lubricating oil film, deposition area and deposition amount decreases compared with dry wall.

Kambe, Hiroki, Mizobuchi, Naoto, Matsumura, Eriko

An Investigation of the Transient DPF Pressure Drop under Cold Start Conditions in Diesel Engines

2017-01-237210/8/2017

To monitor emission-related components/systems and to evaluate the presence of malfunctioning or failures that can affect emissions, current diesel engine regulations require the use of on-board diagnostics (OBD). For diesel particulate filters (DPF), the pressure drop across the DPF is monitored by the OBD as the pressure drop is approximately linear related to the soot mass deposited in a filter. However, sudden acceleration may cause a sudden decrease in DPF pressure drop under cold start conditions. This appears to be caused by water that has condensed in the exhaust pipe, but no detailed mechanism for this decrease has been established. The present study developed an experimental apparatus that reproduces rapid increases of the exhaust gas flow under cold start conditions and enables independent control of the amount of water as well as the gas flow rate supplied to the DPF. The results show that the sudden decrease in the DPF pressure drop is caused by the water in the developed system used here. Observations of the soot cake layers in the DPF show that the decrease in the DPF pressure drop is caused by peeling-off and separation of the soot cake layer from the walls of the DPF. An increase in the water flow rate thins the soot cake layer and decreases the DPF pressure drop. Further, numerical simulation using a DPF model developed by a research group at Waseda University was also performed, and the calculated DPF pressure drop captures the changes obtained by the experiments well.

Kobashi, Yoshimitsu, Oooka, Shun, Jiang, Lin, Goto, Jun, Ogawa, Hideyuki, Shibata, Gen

Diesel Oxidation Catalyst and HC Investigations of a Low RON Gasoline Fuel in a Compression Ignition Engine

2017-01-240510/8/2017

Fuels from crude oil are the main energy vector used in the worldwide transport sector. But conventional fuel and engine technologies are often criticized, especially Diesel engines with the recent “Diesel gate”. Engine and fuel co-research is one of the main leverage to reduce both CO2 footprint and criteria pollutants in the transport sector. Compression ignition engines with gasoline-like fuels are a promising way for both NOx and particulate emissions abatement while keeping lower tailpipe CO2 emissions from both combustion process, physical and chemical properties of the low RON gasoline. To introduce a new fuel/engine technology, investigation of pollutants and After-Treatment Systems (ATS) is mandatory. Previous work [1] already studied soot behavior to define the rules for the design of the Diesel Particulate Filter (DPF) when used with a low RON gasoline in a compression ignition engine. The aim of this study is to investigate the impact of such fuel/engine technology on the Diesel Oxidation Catalyst (DOC) for low load operating conditions. Hydrocarbon (HC) speciation is performed upstream (Us) and downstream (Ds) of the DOC. Warm-up and efficiency are also tested for different operating conditions. To finish, exothermal capacities are considered to ensure high temperature levels for DPF regeneration. Upstream and downstream DOC HC speciation showed heavier molecules for Diesel fuel compared to low RON gasoline and higher carbon balance. These results are consistent with fuel composition. Upstream DOC main HC family is olefin for Diesel while it appears to be paraffin from low RON gasoline. Regardless of the fuel, upstream DOC HC species are mainly C1 to C4 and methane is the major downstream molecule. For steady hot conditions, conversion efficiency of HC and CO for both fuels are quite similar. Differences are highlighted for transient conditions from cold to warm. For low load operating conditions, due to high amounts of HC and CO for low RON gasoline combustion, the catalyst seems to be poisoned and light-off temperatures are higher than Diesel ones. Moreover, the HC storage, during the light-off, is lower when using low RON gasoline. Finally, DOC exotherm for regeneration is possible with low RON gasoline post-injections. For a same fuel quantity injection regardless of the fuel, low RON gasoline has higher upstream DOC HC amount and generates higher exotherms. Despite some differences in the HC species between Diesel and low RON gasoline, conversion efficiency and DOC exotherm are quite similar. Nevertheless, the light-off and the HC-storage during a warm-up phase could be different and need more investigations.

Chaillou, Christophe, Bouet, Alexandre, Frobert, Arnaud, Duffour, Florence

The Combustion Modeling of the Heavy-Duty Diesel Engine Based on Genetic Programming

2017-01-218510/8/2017

More and more stringent emission regulations and the desire to reduce fuel consumption lead to an increasing demand for precise and close-loop combustion control of diesel engines. Cylinder pressure-based combustion control is gradually used for diesel engines in order to enhance emission robustness and reduce fuel consumption. However, it increases the cost. In this paper, a new prediction method of combustion parameters is presented for diesel engines. The experiment was carried out on a test bench to obtain the ECU (Electronic Control Unit) signals of a heavy-duty diesel engine by calibration software. The combustion parameters was measured by a combustion analyzer, such as maximum cylinder pressure (MCP), maximum combustion temperature (MCT), and combustion center of gravity (CA50). A combustion model using genetic programming (GP) is built. The input parameters are chosen from the ECU signals, such as engine speed, engine load, injection quantities, inlet air flow rate. The output parameters are MCP, MCT and CA50. The combustion model is trained and validated by measurement data. The results indicate that the combustion model can be built with the input variables of engine speed, fuel injection quantities, inlet air flow rate, inlet air temperature and exhaust air temperature. The correlation coefficient between simulation and experiment data for MCP, MCT and CA50 are over 0.90 and the average relative error is blow 4.0%.

He, Chao, Li, Jiaqiang, Zhao, Longqing, Wang, Yanyan, Gu, Wei

Simulation of Catalyzed Diesel Particulate Filter for Active Regeneration Process Using Secondary Fuel Injection

2017-01-228710/8/2017

Advanced exhaust after-treatment technology is required for heavy-duty diesel vehicles to achieve stringent Euro VI emission standards. Diesel particulate filter (DPF) is the most efficient system that is used to trap the particulate matter (PM), and particulate number (PN) emissions form diesel engines. The after-treatment system used in this study is catalyzed DPF (CDPF) downstream of diesel oxidation catalyst (DOC) with secondary fuel injection. Additional fuel is injected upstream of DOC to enhance exothermal heat which is needed to raise the CDPF temperature during the active regeneration process. The objective of this research is to numerically investigate soot loading and active regeneration of a CDPF on a heavy-duty diesel engine. In order to improve the active regeneration performance of CDPF, several factors are investigated in the study such as the effect of catalytic in filter wall, soot distribution form along filter wall, and soot loads. This paper also presents simulation results of temperature, pressure, and soot distribution in the CDPF. The after-treatment model is validated by comparing the simulation results with the measured data, and small deviation is obtained between the measured data and numerical results. Soot loading simulation indicates that soot accumulation is non-uniform along the CDPF, where higher soot accumulation at the end of filter monolith is observed. Moreover, the lowest soot accumulation occurs in the region near CDPF entrance. 3D contour images of regeneration simulation show that the soot oxidation rate of the filter increases when accumulated soot mass increases and temperature profile increases. Simulation results of catalyzed DPF (CDPF) reveal that additional exothermic reaction on wall improves the regeneration performance.

Abdalla, Aniseh, Wang, Guoyang, Zhang, Jun, Shuai, Shi-Jin

Analysis of Spray Feature Injected by Tailpipe Injector for Aftertreatment of Diesel Engine Emissions

2017-01-237310/8/2017

Diesel Particulate Filter (DPF) is a very effective aftertreatment device to limit particulate emissions from diesel engines. As the amount of soot collected in the DPF increases, the pressure loss increases. Therefore, DPF regeneration needs to be performed. Injected fuel into the exhaust line upstream of the Diesel Oxidation Catalyst (DOC), hydrocarbons are oxidized on the DOC, which increases the exhaust gas temperature at the DPF inlet. It is also necessary that the injected fuel is completely vaporized before entering the DOC, and uniformly mixed with the exhaust gases in order to make the DOC work efficiency. However, ensuring complete evaporation and an optimum mixture distribution in the exhaust line are challenging. Therefore, it is important that the fuel spray feature is grasped to perform DPF regeneration effectively. The purpose of this study is the constructing a simulation model. The secondary fuel injection is classified into free spray, impingement spray, evaporation of liquid-film, and HC concentration distribution. So it is difficult to predict phenomena because each phenomenon is complicatedly involved. Therefore, it is necessary that each phenomenon is evaluated in basic experiment. This report focuses on impingement spray on the wall under high temperature field by LIEF and LIF method and spray under the flow field by scattered light method and compares experimental results with numerical analysis results. As a result, it is clarified that the gas phase due to fuel evaporation has a distribution near the wall when Pinj is 1MPa under high temperature field. On the other hand, the gas phase is widely distributed when Pinj is 4MPa because droplets are involved in the vortex. Also, it is clarified that swirl spray does not form follow up spray under the flow field because droplets are given momentum by flow.

Kaniyu, Jun, Sakatani, Shogo, Matsumura, Eriko, Kitamura, Takaaki

Dilute Measurement of Semi-Volatile Organic Compounds (SVOC) from a Heavy-Duty Diesel Engine

2017-01-239310/8/2017

Semi-volatile organic compounds (SVOC) are a group of compounds in engine exhaust that either form during combustion or are part of the fuel and lubricating oil. Since these compounds occur at very low concentrations in diesel engine exhaust, the methods for sampling, handling, and analyzing these compounds are critical to obtaining good results. An improved dilute exhaust sampling method was used for sampling and analyzing SVOC in engine exhaust, and this method was performed during transient engine operation. A total of 22 different SVOC were measured using a 2012 medium-duty diesel engine. This engine was equipped with a stock diesel oxidation catalyst (DOC), a diesel particulate filter (DPF), and a selective catalytic reduction (SCR) catalyst in series. Exhaust concentrations for SVOC were compared both with and without exhaust aftertreatment. Concentrations for the engine-out SVOC were significantly higher than with the aftertreatment present. Distribution of the SVOC between semi-volatile- and particulate-phase depended on the number of aromatic rings, the molecular weight, and the volatility of the compounds detected.

Fanick, E. Robert, Kroll, Svitlana

Kinetic Modeling Study of NOx Conversion Based on Physicochemical Characteristics of Hydrothermally Aged SCR/DPF Catalyst

2017-01-238610/8/2017

Diesel engines have better fuel economy over comparable gasoline engines and are useful for the reduction of CO2 emissions. However, to meet stringent emission standards, the technology for reducing NOx and particulate matter (PM) in diesel engine exhaust needs to be improved. A conventional selective catalytic reduction (SCR) system consists of a diesel oxidation catalyst (DOC), diesel particulate filter (DPF), and urea-SCR catalyst. Recently, more stringent regulations have led to the development of SCR systems with a larger volume and increased the cost of such systems. In order to solve these problems, an SCR catalyst-coated DPF (SCR/DPF) is proposed. An SCR/DPF system has lower volume and cost compared to the conventional SCR system. The SCR/DPF catalyst has two functions: combustion of PM and reduction of NOx emissions. As PM is removed from the DPF at high temperatures (>650°C), the SCR/DPF system is exposed to higher temperatures as compared with those in the conventional SCR system. In this study, we investigated the NOx reduction performance and the properties of a hydrothermally aged SCR/DPF catalyst. Using these data, a model that can predict the NOx conversion of the hydrothermally aged SCR/DPF catalyst was constructed. A commercial copper-exchanged zeolite catalyst, Cu-ZSM-5, was used and aged in synthetic air with 10% water over the temperature range 650-750 °C. The effects of hydrothermal aging on the catalysts were investigated using a synthetic gas bench, and a detailed analysis of the structure of the hydrothermally aged catalyst was performed. Using the experimental data, we succeeded in constructing a hydrothermally aged SCR/DPF model for predicting the NOx conversion based on changes in the physicochemical characteristics of the catalysts with changes in the hydrothermal aging conditions. This work is the first step toward bridging the gap between a lab-simulated performance model and the global reactivity observed under real-world conditions.

Ohya, Naoki, Hiyama, Kohei, Tanaka, Kotaro, Konno, Mitsuru, Tomita, Atsuko, Miki, Takeshi, Tai, Yutaka

Fast Hybrid Sensor for Soot of Production CI Engines

2017-24-01379/4/2017

During transients, engines tend to produce substantially higher peak emissions like soot - the main fraction of particular matter (PM) - which are the longer the more important as the steady state emissions are better controlled. While Diesel particulate filters are normally able to block them, preventing their occurrence would of course be more important. In order to achieve this goal, however, they must be measurable. While for most emissions commercial sensors of sufficient speed and performance are available, the same is not true for PMs, especially for production engines. Against this background, in the last years the possible use of a full stream 50Hz sensor based on Laser Induced Incandescence (LII) was investigated, and the results were very encouraging, showing that the sensor could recognize transient changes undetected by conventional measurement systems (like the AVL Opacimeter) but confirmed by the analysis of combustion. This was also related to the position of the sensor which can be mounted upstream or downstream of the turbine in a turbocharged CI engine. The measurement is instantaneous, without dilution or transport, and this raises also the question about accuracy, as the variability of the particulate flow near to the sensor will be directly visible in the sensor output. To reduce this effect, we propose a hybrid sensor approach in which the final reading is computed by a suitable combination of the output of the photodiodes and operation information of the engine, e.g. the pressure and temperature near to the sensor location. This paper presents the methodology as well as an experimental assessment. All measurements have been done on a production 2 lt Euro 5 CI engine.

Zhang, Zhen, del Re, Luigi, Fuerhapter, Richard

Catalyst and DPF Acoustic Transmission Loss Benchmark Study

2017-01-17986/5/2017

The ability to accurately predict exhaust system acoustics, including transmission loss (TL) and tailpipe noise, based on CAD geometry has long been a requirement of most OEM’s and Tier 1 exhaust suppliers. Correlation to measurement data has been problematic under various operating conditions, including flow. This study was undertaken to develop robust modelling technique, ensuring sensible correlation between the 1-D models and test data. Ford use Ricardo WAVE as one of their 1-D NVH tools, which was chosen for the purpose of this benchmark study. The most commonly used metrics for evaluating the acoustical performance of mufflers are insertion loss (IL), TL, and noise reduction (NR). TL is often the first step of analysis, since it represents the inherent capability of the muffler to attenuate sound if both the source and termination are assumed to be anechoic. It can also be reliably measured and numerically simulated without having to connect to an engine. For the purpose of software validation, TL benchmarking should be the first step. This study focused around two key exhaust components: Catalysts and Diesel Particulate Filter (DPF), with TL measurements collected for validation purposes. These measurements were compared to simulation data to validate Ricardo WAVE models that directly reflected the test set up. Differences were identified, and model sensitivities studies conducted resulting in revised modeling recommendations for CAT’s and DPF’s. This resulted in more accurate modelling of TL before any hardware is procured.

Navratil, Jiri, Seeley, Warren, Wang, Peng, Siravara, Shriram

Determination of Heavy Truck Noise Sources under Actual Highway Operating Conditions Using Acoustic Beamforming

2017-01-18376/5/2017

Acoustic beamforming was used to localize noise sources on heavy trucks operating on highways in California and North Carolina at a total of 20 sites. Over 1,200 trucks were measured under a variety of operating conditions, including cruise on level highways, on upgrades, down degrades, low speed acceleration, and for various speeds and pavements. The contours produced by the beamforming measurements were used to identify specific source contributions under these conditions and for a variety of heavy trucks. Consistently, the highest noise levels were seen at the tire-pavement interface, with lesser additional noise radiated from the engine compartment. Noise from elevated exhaust stacks was only documented for less than 5% of the trucks measured. The results were further reduced to produce vertical profiles of noise levels versus height above the roadway. The profiles were normalized to the highest noise level at ground level. The profile averages from each measurement site were found to be independent of speed and operating conditions and were consistent from site-to-site. The highest levels were also related to the tire-pavement noise measured, independently, using on-board sound intensity methods. The results of this research are presented, and their implications for highway noise and noise modeling are discussed.

Donavan, Paul R., Janello, Carrie

Modelling and Optimization of Plug Flow Mufflers in Emission Control Systems

2017-01-17826/5/2017

Large-scale emergency or off-grid power generation is typically achieved through diesel or natural gas generators. To meet governmental emission requirements, emission control systems (ECS) are required. In operation, effective control over the generator’s acoustic emission is also necessary, and can be accomplished within the ECS system. Plug flow mufflers are commonly used, as they provide a sufficient level of noise attenuation in a compact structure. The key design parameter is the transmission loss of the muffler, as this dictates the level of attenuation at a given frequency. This work implements an analytically decoupled solution, using multiple perforate impedance models, through the transfer matrix method (TMM) to predict the transmission loss based on the muffler geometry. An equivalent finite element model is implemented for numerical simulation. The analytical results and numerical results are then evaluated against experimental data from literature. The transmission loss required in each application of the ECS system will vary depending on the noise profile of the generator in question; therefore, it is necessary to have an effective method of redesigning the muffler to meet the design requirements. Prior work on TMM-based muffler shape optimization utilized complex algorithms such as neural networks and simulated annealing. The present study simplifies the process by using the bounded, limited-memory implementation of the Broyden-Fletcher-Goldfarb-Shanno (BFGS) algorithm in a multi-start framework for shape optimization to achieve the desired transmission loss. By constraining the multi-start method with appropriate design limits, the algorithm is initialized at multiple random points within the design space, ensuring that the solution approaches the global optimum when using a sufficiently large number of initializations.

Puthuparampil, Jobin, Pong, Henry, Sullivan, Pierre

Pressure Drop and Soot Accumulation Characteristics through Diesel Particulate Filters Considering Various Soot and Ash Distribution Types

2017-01-09593/28/2017

Although diesel engines offer higher thermal efficiency and lower fuel consumption, larger amounts of Particulate Matters (PM) are emitted in comparison with gasoline engines. The Diesel Particulate Filters (DPF) have proved one of the most promising technologies due to the “particle number” emissions regulations. In this study, the Computational Fluid Dynamics (CFD) multi-channel model of DPF was built properly by utilizing AVL-Fire software code to evaluate the pressure drop and soot accumulation characteristics of DPF. The main objective of this paper was to investigate the effects of soot (capacity and deposit forms) and ash (capacity and distribution factors) interaction on DPF pressure drop and soot accumulation, as well as the effects of DPF boundary conditions (inlet mass flow rate and inlet temperature) on pressure drop. The Asymmetric Cell Technology (ACT) of DPF was proposed to evaluate the effects of the inlet to outlet width ratios on pressure drops and soot regeneration, and optimize the filter structure in practical applications. The results showed that the pressure drop sensitivity increases with the increased DPF inlet mass flow, inlet temperature, soot loading and ash accumulation, and the pressure drop change is not linear relationship with inlet temperature. The PM distribution is non-uniform and both ends of DPF contain a higher soot loading than the middle part. The “Linear decrease” soot pattern has a lower pressure loss and faster regeneration rate. The ash deposited on inlet channel walls results in larger pressure drops and prevents soot accumulation in the pores dramatically compared with ash deposited as plug. The ACT design filter can reduce the pressure drop, improve the soot accumulation performance, and accelerate regeneration rate at high soot and ash loads.

Zhao, Changpu, Zhu, Yayong, Huang, Sirui

A Review of the Literature on Modelling of Integrated SCR-in-DPF Systems

2017-01-09763/28/2017

The integration of selective catalytic reduction catalysts (SCR) into diesel particulate filters (DPF) as a way to treat nitrogen oxides (NOx) and particulate matter (PM) emission is an emerging technology in diesel exhaust aftertreatment. This is driven by ever-tightening limits on NOx and PM emission. In an integrated SCR-in-DPF (also known as SCRF®, SCR-on-DPF, SDPF, or SCR coated filter), the SCR catalyst is impregnated within the porous walls of the DPF. The compact, low weight/volume of the integrated unit provides improvement in the diesel engine cold start emission performance. Experimental investigations have shown comparable performance with standard SCR and DPF units for NOx conversion and PM control, respectively. The modelling of the integrated unit is complicated. The main challenge is how to best capture the complexity of the physical phenomena-e.g., the competition of soot oxidation and SCR reaction for available NO2, or the interaction of washcoat loading on deNOx performance, PM filtration efficiency and system pressure drop-in a simplified but adequate representation. This paper reviews the approaches to SCR-in-DPF modelling obtained from published materials. It discusses the specific considerations given to adapting coated (catalysed) DPF model for SCR-in-DPF modelling. This includes characterisation of SCR model and associated kinetics, inclusion of ammonia dynamics and interaction with soot in the transport model, and careful model calibration to capture the salient phenomena in the system. This work presents current research in SCR-in-DPF modelling and highlights potential areas of future research. It can serve as a resource for new researchers in SCR-in-DPF modelling

Olowojebutu, Seun, Steffen, Thomas

Pressure Drop and Soot Regeneration Characteristics through Hexagonal and Square Cell Diesel Particulate Filters

2017-01-09793/28/2017

Although diesel engines have higher output torque, lower fuel consumption, and lower HC pollutant emissions, larger amounts of NOx and PM are emitted, compared with equivalent gasoline engines. The diesel particulate filters (DPF) have proved one of the most promising aftertreatment technologies due to the more stringent particulate matters (PM) regulations. In this study, the computational fluid dynamics (CFD) model of DPF was built by utilizing AVL-Fire software code. The main objective of this paper was to investigate the pressure drop and soot regeneration characteristics of hexagonal and conventional square cell DPFs with various inlet mass flow rates, inlet temperatures, cell densities, soot loads and ash loads. Different cell geometry shapes of DPF were evaluated under various ash distribution types. Results showed that, in comparison with the conventional square cell DPF, a remarkable increase of regeneration efficiency and soot oxidation rate of hexagonal cell DPF is confirmed. The optimal cell density range is (220-260)/ inch2. The ash deposited on inlet channel walls results in larger pressure drop and prevents soot accumulation in the pores dramatically compared with ash deposited as plug. In addition, the hexagonal cell DPF has a lower pressure drop than square cell DPF at high soot and ash loads. In a word, the hexagonal cell DPF exhibits a better performance of soot capacity and soot regeneration than square cell filter, which reduces the regeneration frequency and prolongs the DPF life.

Zhao, Changpu, Zhu, Yayong, Wang, Yaohui, Huang, Sirui

NO ₂ /NOx Ratio and NH ₃ Storage Estimation of Automotive SCR Multi-Brick Systems

2017-01-09723/28/2017

Many control approaches for selective catalytic reduction (SCR) systems require knowledge of ammonia storage (NH3 storage) to dose urea accurately. Currently there are no technologies to directly measure internal NH3 storage in a vehicle, so it can only be inferred from hardware sensors located upstream, downstream, or in the catalyst. This paper describes an application of extended Kalman filter (EKF) state estimator used as a virtual sensor for urea injection control of a multi-brick aftertreatment system. The proposed estimator combines mean-value physics-based models of combined SCR and diesel particulate filter (SCR/DPF), SCR and clean-up catalyst (CUC). It uses hardware sensors at the inlet and outlet of the aftertreatment system, and includes no sensors between the catalysts. Performance of the proposed estimator was validated in simulations against a high-fidelity model of the aftertreatment system. The algorithm provides accurate estimates of the dominant gaseous species NOx and NH3 as well as NH3 storage for a feedback model predictive control (MPC) control of urea injection. Moreover, the algorithm is able to estimate upstream NO2/NOx ratio from provided constant reference. The proposed estimator is a link in the model-based control design toolchain aimed for post-EURO 6 RDE-compliant light-duty vehicle design. Together with the MPC controller they are capable of running in real-time on current production hardware.

Figura, Jiri, Pekar, Jaroslav, Krejza, Pavel, Mracek, David, von Wissel, Dirk, Zhang, Tianran

Emission Performance of Low Cetane Naphtha as Drop-In Fuel on a Multi-Cylinder Heavy-Duty Diesel Engine and Aftertreatment System

2017-01-10003/28/2017

Greenhouse gas regulations and global economic growth are expected to drive a future demand shift towards diesel fuel in the transportation sector. This may create a market opportunity for cost-effective fuels in the light distillate range if they can be burned as efficiently and cleanly as diesel fuel. In this study, the emission performance of a low cetane number, low research octane number naphtha (CN 34, RON 56) was examined on a production 6-cylinder heavy-duty on-highway truck engine and aftertreatment system. Using only production hardware, both the engine-out and tailpipe emissions were examined during the heavy-duty emission testing cycles using naphtha and ultra-low-sulfur diesel (ULSD) fuels. Without any modifications to the hardware and software, the tailpipe emissions were comparable when using either naphtha or ULSD on the heavy duty test cycles. Overall lower CO2 emissions and fuel consumption were measured for naphtha due in part to its higher heating value and higher hydrogen to carbon ratio. Engine-out and tailpipe NOx emissions were lower for naphtha, and measured PM emissions were also lower due to naphtha’s higher volatility and lower aromatic content compared to ULSD. To help assess the potential impact on diesel particulate filter design and operation, engine-out PM samples were collected and characterized at a steady-state mid-speed, mid-load operating point. A significant reduction in elemental carbon in PM samples was observed for naphtha fuel, and similar oxidation rates and peak oxidation temperatures were measured for the PM from both fuels.

Lee, Jong, Zhang, Yu, Tzanetakis, Tom, Traver, Michael, Moses-DeBusk, Melanie, Storey, John, Partridge, William, Lance, Michael

After-Treatment Systems to Meet China NS VI, India BS VI Regulation Limits

2017-01-09413/28/2017

Future emissions regulations proposed for the Asian automotive industry (BS VI regulations for India and NS VI regulations for China) are strict and similar to EU VI regulations. As a result, they will require both advanced NOx control as well as advanced Particulate Matter (PM) control. This will drive implementation of full Catalyzed Diesel Particulate Filter (cDPF) and simultaneous NOx control using Selective Catalytic Reduction (SCR) technologies. In this work, we present the performance of various Diesel Oxidation Catalyst (DOC), cDPF, SCR and Ammonia slip catalyst (ASC) systems utilizing the World Harmonized Transient Cycle (WHTC). Aftertreatment Systems (ATS) required for both active and passive filter regeneration applications will be discussed. The sensitivity of key design parameters like catalyst technology, PGM loading, catalyst sizing to meet the regulation limits has been investigated. The impact of operating conditions like cycle temperature and urea dosing strategy on the overall performance has also been studied. Model simulations and experimental validations along with thermal management studies have been conducted to propose a suitable ATS for India BS VI and China NS VI applications.

Yang, Liu, Sukumar, Balaji, Naseri, Mojghan, Markatou, Penelope, Chatterjee, Sougato

A Modeling Analysis of Fibrous Media for Gasoline Particulate Filters

2017-01-09673/28/2017

With an emerging need for gasoline particulate filters (GPFs) to lower particle emissions from gasoline direct injection (GDI) engines, studies are being conducted to optimize GPF designs in order to balance filtration efficiency, backpressure penalty, filter size, cost and other factors. Metal fiber filters could offer additional designs to the GPF portfolio, which is currently dominated by ceramic wall-flow filters. However, knowledge on their performance as GPFs is still limited. In this study, modeling on backpressure and filtration efficiency of fibrous media was carried out to determine the basic design criteria (filtration area, filter thickness and size) for different target efficiencies and backpressures at given gas flow conditions. Filter media with different fiber sizes (8 - 17 μm) and porosities (80% - 95%) were evaluated using modeling to determine the influence of fiber size and porosity. A comparison of design criteria for fibrous filters and their ceramic counterparts is also discussed.

Liu, Xin, Kim, Jeong, Chanko, Timothy, Lambert, Christine, Pakko, James

Development of a Particulate Filter Model for the Prediction of Backpressure: Improved Momentum Balance and Entrance and Exit Effect Equations

2017-01-09743/28/2017

The development of a one-dimensional model for the prediction of backpressure across a gasoline or diesel particulate filter (PF) is presented. The model makes two innovations: Firstly, the term for momentum convection in the gas momentum balance equations includes the loss (or gain) of axial momentum in the direction perpendicular to the channels; neglecting this results in the momentum convection term being too large. Secondly, equations for the pressure change due to the abrupt contraction at the PF entrance and for abrupt expansion at the exit are derived which take into account the fact that the velocity profile across the channels is not flat; often workers have used equations appropriate for high Reynolds numbers which assume flat velocity profiles. The model has been calibrated/tested against cold flow data for more than one length of PF. The use of more than one length allows along-filter pressure losses to be separated from entrance and exit effects. A simulation study has been carried out to investigate the relative magnitude of the different contributions to backpressure, viz. across-wall losses (Darcy and Forchheimer), along-channel losses (viscous and inertial) and entrance and exit effects. Finally, other workers have recently published a PF model in which the effect of the wall Reynolds number on the friction factors, Nusselt numbers and momentum transport has been included. The influence of these modifications on the backpressure and outlet temperature prediction has been investigated and found not to be significant over the range of conditions tested.

Watling, Timothy C., Ravenscroft, Maya R., Cleeton, Jason P.E., Rees, Ian D., Wilkins, David A.R.

Experimental Methodology for the Understanding of Soot-Fuel Relationship in Diesel Combustion: Fuel Characterization and Surrogate Validation

2017-01-07213/28/2017

This paper is a contribution to the understanding of the formation and oxidation of soot in Diesel combustion. An ECN spray A injector (single axial-oriented orifice) was tested in a well characterized high-temperature/high-pressure vessel at engine relevant conditions. The size of the test section (>70mm) enables to study the soot formation process in nearly free field conditions, which constitutes an ideal feature for fundamental understanding and model validation. Simultaneous high-speed OH* chemiluminescence imaging and high-speed 2D extinction were performed to link together the information regarding flame chemistry (i.e. lift-off length) and the soot data. The experiments were carried out for a set of fuels with different CN and sooting index (Diesel fuel, Jet fuel, gasoline and n-dodecane) performing parametric variations in the test conditions (ambient temperature and oxygen concentration). The methodology proposed allowed a qualitative evaluation of the main fuel characteristics affecting soot formation in Diesel combustion identified as Cetane Number (CN) and threshold sooting index (TSI). The experiments enabled the characterization of properties depending on these two features, and therefore a fuel characterization at engine relevant conditions. For CFD soot modeling purposes, three surrogate fuels were designed to mimic the behavior of the practical fuels tested matching their CN and TSI. The characterization methodology was used to validate/correct the surrogates’ composition in order to correctly reproduce the behavior of the practical fuels. The fuel characterization methodology, the experimental data gathered as well as the composition of the validated fuel surrogate for soot modeling at typical Diesel conditions are considered three major outcomes of this work.

Bardi, Michele, Bruneaux, Gilles, Nicolle, André, Colin, Olivier

Items per page:

1 – 50 of 400