Browse Topic: Particulate filters

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Medium/Heavy-Duty E/E Systems Diagnosis NomenclatureJ2403_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 - DiagnosticsJ1939/73_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 Loading2020-01-14334/14/2020
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
Relevance of Exhaust Aftertreatment System Degradation for EU7 Gasoline Engine Applications2020-01-03824/14/2020
Exhaust aftertreatment systems must function sufficiently over the full useful life of a vehicle. In Europe this is currently defined as 160.000 km. With the introduction of Euro 7 it is expected that the required mileage will be extended to 240.000 km. This will then be consistent with the US legislation. In order to quantify the emission impact of exhaust system degradation, an Euro 7 exhaust aftertreatment system is aged by different accelerated approaches: application of the Standard Bench Cycle, the ZDAKW cycle, a novel ash loading method and borderline aging. The results depict the impact of oil ash on the oxygen storage capacity. For tailpipe emissions, the maximum peak temperatures are the dominant aging factor. The cold start performance is effected by both, thermal degradation and ash accumulation. An evaluation of this emission increase requires appropriate benchmarks. For this purpose, an analysis of the emission impacts of ambient temperatures, driving modes and particulate filter regenerations follows. The comparison shows the severe impact of very low ambient conditions. Considering the high statistical relevance of catalyst degradation however, full useful life optimization requires special attention for Euro 7 gasoline engine applications.
Sterlepper, Stefan, Claßen, Johannes, Pischinger, Stefan, Görgen, Michael, Cox, Jim, Nijs, Martin, Scharf, Johannes
Analysis of TWC Characteristics in a Euro6 Gasoline Light Duty Vehicle2019-24-01629/9/2019
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
Numerical Study of Pore Size and Distribution Effects on Gasoline Particulate Filter Performance03-12-05-00328/22/2019
Abstract The improved brake thermal efficiency of Gasoline Direct Injection (GDI) engines is accompanied by a significant increase in Particulate Matter (PM) mass and higher Particulate Number (PN) emissions as compared to (multi)Port Fuel Injected (PFI) engines. Gasoline particulate filters (GPFs) with high filtration efficiency and low backpressure will be required to meet the future, stringent PM/PN regulations. A two-dimensional (2D) CFD study was performed to determine the effects of pore size and distribution on the interdependent performance parameters of filtration efficiency and backpressure for clean GPFs. Simulation results show an on linear change infiltration efficiency as the pore size distribution tightens and determine a recommended distribution range, controlling the quantity of small-sized pores. Pore size distributions beyond this recommended range can cause a filtration performance loss or intolerable backpressure penalty for the GPF. In addition, a recent collaborative publication from our group has demonstrated our ability to create a hierarchical porous filter, with variable pore size in each layer. Knowing that filtration efficiency and pressure drop increase as the average pore size decreases offers inspiration for a novel wall design with small pores comprising the top 40% of the wall layers and larger pores on bottom 60%. The model predicts that such a wall would result in an 8% increase in filtration efficiency.
Yang, Pengze, Strzelec, Andrea
ELECTRIC MACHINES find their niche19TOFHP08_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.
Morey, Bruce
Deposit Reduction in SCR Aftertreatment Systems by Addition of Ti-Based Coordination Complex to UWS2019-01-03134/2/2019
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 Characteristics2019-01-01904/2/2019
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 DPF2019-01-09854/2/2019
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 Bus2019-01-06354/2/2019
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 Applications2019-01-05864/2/2019
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
Ash Transport and Deposition, Cake Formation and Segregation-A Modeling Study on the Impact of Ash on Particulate Filter Performance2019-01-09884/2/2019
Non-combustible particles, commonly summarized as ash, influence the lifetime performance of wall flow filters. This study aims to investigate this influence by means of simulation. An existing transient 1D+1D wall flow filter model is extended by dedicated transport balances for soot and ash (1), by a discrete cake model describing changing soot and ash compositions over the cake height (2), by a phenomenological cake filtration model (3), by dedicated cake property models (4) and by a phenomenological model capturing the radial mobility of solids within the cake (5). Results of three different types of simulations are shown. First, the various sub-models are assessed in isolated simulation configurations. The combination of these shall serve as theoretical model validation. Second, isolated loading and passive regeneration simulations are performed. This aims to identify the impact of different filtration and cake migration constants on soot and ash segregation (i.e. ash accumulation) and on soot conversion performance. Third, the impact of ash during a combined loading and passive regeneration cycle is investigated. This aims to identify the impact of ash on the formation of a soot balance point.
Wurzenberger, Johann C., Kutschi, Susanne, Nikodem, Astrid
Sensitivity Study on Thermal and Soot Oxidation Dynamics of Gasoline Particulate Filters2019-01-09904/2/2019
Gasoline particulate filters (GPFs) are devices used to filter soot emitted by gasoline direct injection (GDI) engines. A numerical model for a ceria-coated GPF presented in a previous paper by H. Arunachalam et al. in 2017 was developed to predict internal temperature and soot amount combusted during regeneration events. Being that both the internal temperature and the accumulated soot cannot be directly measured during real-time operation and owing to their critical importance for GPF health monitoring as well as regeneration scheduling, the above model turns out to be a valuable tool for OBD applications. In this paper, we first conduct a stochastic analysis to understand the relation between the model parameters and the initial value of the ceria (IV) oxide volume fraction, as a deterministic value for such a state is not known. A particle swarm optimization (PSO) algorithm was employed to define what type of relationship the model parameters were with respect to the initial state of the ceria (IV) oxide volume fraction. A sensitivity study is then conducted over the model parameters to study parameter identifiability from system measurements. Effects of the initial temperature and initial amount of soot were studied as well. Results indicated that the model is most sensitive to the activation energy of GPF regeneration, agreeing with previous studies. Additionally, the model was shown to be able to predict the GPF temperature with less than 5% error when there was at most 20% uncertainty in the parameters. The results of the relationship between ceria (IV) oxide and the parameters, as well as the sensitivity analysis can be used simultaneously in the future for observer-based design.
Takahashi, Aki, Korneev, Slava, Onori, Simona
Review of Vehicle Engine Efficiency and Emissions2019-01-03144/2/2019
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.
Joshi, Ameya
Smart DPF Regenerations - A Case Study of a Connected Powertrain Function2019-01-03164/2/2019
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
Regeneration Strategies for Gasoline Particulate Filters2019-01-09694/2/2019
Gasoline particulate filters (GPFs) are extremely effective at reducing tailpipe emissions of particulate mass and particulate number. Especially in the European and Chinese markets, where a particulate number standard is legislated, we see gasoline particulate filters being deployed in production on gasoline direct injected engines. Due to the high temperature in gasoline exhaust, most applications are expected to be passively regenerating without the help of an active regeneration strategy. However, for the few cases where a customer drive cycle has consistently low speed over a long time frame, an active regeneration strategy may be required. This involves increasing the exhaust temperature at the GPF up to around 600 degC so that soot can be combusted. We compare two different ways of achieving these temperatures, namely spark retard and air fuel ratio modulation. The former generates heat in the engine, the latter generates heat in one or more catalysts in the exhaust system. We list some benefits and drawbacks of both methods, and validate our work with experimental data.
Van Nieuwstadt, Michiel, Shah, Anil, Serban, Emil, Martin, Douglas
Application Layer - DiagnosticsJ1939/73_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 Substrates2019-01-00521/15/2019
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 Blocking2019-01-00491/15/2019
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.
Benchtop Investigation of Filtration Efficiency and Pressure Drop Behavior of Commercial High Porosity Gasoline Particulate Filters2019-01-00541/15/2019
The increasing number of gasoline direct injection (GDI) vehicles on the roads has drawn attention to their particulate matter (PM) emissions, which are greater both in number and mass than port fuel injected (PFI) spark ignition (SI) engines [1]. Regulations have been proposed and implemented to reduce exposure to PM, which has been shown to have negative impacts on both human health and the environment [2, 3]. Currently, the gasoline particulate filter (GPF) is the proposed method of reducing the amount of PM from vehicle exhaust, but modifications to improve the filtration efficiency (FE) and reduce the pressure drop across the filter are yet needed for implementation of this solution in on-road vehicles. This work evaluates the impacts of wall thickness and cell density on filtration efficiency and backpressure using a benchtop filtration system. For both unmodified and modified GPFs, the filtration efficiency was studied using a scanning mobility particle sizer (SMPS), and the pressure drop across the filter was obtained using a differential pressure transducer. The performance of the unmodified GPFs were investigated at three space velocities: 15,000 hr-1, 30,000 hr-1, and 60,000 hr-1. Increasing space velocity through unmodified GPFs results in decreasing FE by approximately 5% for every 15,000 hr-1 increase, which means a GPF has its lowest FE and highest pressure drop at 60,000 hr-1. The GPF with lowest initial FE and pressure drop, 300-10, was modified by preloading calcium sulfate (CaSO4) to form a cake layer on the walls. The improvement of about 10% to the filtration efficiency and increase of about 6% to the pressure drop when loaded to 20 g/L indicates that a preloaded cake layer can improve performance with less penalty than increasing wall thickness.
Porter, Quinton, Strzelec, Andrea
An Experimental Study of the Effects of Coolant Temperature on Particle Emissions from a Dual Injection Gasoline Engine2019-01-00511/15/2019
Euro VI emission standards have set a very strict limitation on particulate matter emissions of Gasoline Direct Injection (GDI) engine. It is difficult for GDI engine to meet the Euro VI PN regulation (6×1011#/km) without a series of complicated after-treatment devices such as Gasoline Particulate Filter (GPF). Previous research shows that GDI vehicles under cold start condition account for more than 50% of both particle number and mass emissions during the entire NEDC driving cycle. Dual Injection Gasoline engine is based on the GDI engine by adding a set of port fuel injection system. The good mixing characteristics of the port fuel injection system can help to reduce the particulate matter emissions of the GDI engine during the cold start condition. In this study, a Cambustion DMS500 fast particle spectrometer was employed to characterize the effects of coolant temperature and direct injection ratio on particulate emissions from a turbocharged four-cylinder dual-injection gasoline engine. The experimental results showed that with the coolant temperature increasing the particulate matter tended to be consistent under the port fuel injection mode. The particulate matter showed significantly drop with the coolant temperature increasing both in the dual injection mode and the direct injection mode. At the same coolant temperature, with the decrease of the direct injection ratio, the particulate matter showed notably reductions, and with the increase of coolant temperature, the magnitude of the reductions gradually declined. The experimental results provided important guidance to reduce the particulate matter via dual injection mode during the cold start condition.
Xia, Chun, Chen, Wenhao, Fang, Junhua, Huang, Zhen
Medium/Heavy-Duty E/E Systems Diagnosis NomenclatureJ2403_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 Device2018-32-001510/30/2018
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 industry18TOFHP10_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.
Borst, Matthew
Engine Accelerated Aging Method Developed to Study the Effect of Lubricant Formulations on Catalyzed Gasoline Particulate Filter Durability2018-01-18049/10/2018
Catalyzed gasoline particulate filter (cGPF) is the prime technology to meet future stringent regulations for particulates from gasoline direct injection (GDI) engines. One of the technical concerns is the ultimate durability of cGPF in regards to engine lubricant formulations. This study investigated two tailored lubricant formulations on catalyzed GPFs which were aged on engine followed by emission testing on vehicle. An engine accelerated aging protocol was developed for cGPFs to simulate thermal aging, ash and soot loading that is at least equivalent to 200,000 km durability requirement. Evaluations include tailpipe emission levels, backpressure, catalytic performance, and post-mortem analysis. Both formulations have demonstrated a high level of cGPF performance retention; performance being assessed in terms of emission level at the end of durability demonstration testing. These formulations provide flexibility in selecting robust lubricant to meet various system requirements.
Shao, Huifang, Carpentier, Guillaume, Yin, Danhua, Wang, Yinhui, Remias, Joesph, Roos, Joseph, Xia, Wenzheng, Zheng, Yi, Yuan, Xinbo, Yang, Dongxia, He, Xiaokun, Yin, Zenghui
The Use of Ozone in Low Temperature Methane Control for Natural Gas Applications2018-01-17029/10/2018
Lean operating natural gas heavy duty applications have advantages in terms of lower CO2 and PM compared to Diesel applications. This makes operating heavy duty applications on natural gas attractive and currently, they do not have to implement an exhaust particulate filter. However, the challenge is controlling methane emissions over a range of vehicle operating conditions. Methane is extremely stable and light off occurs at temperatures above 400 °C, with high efficiency occurring >500 °C and requires high precious metal loaded catalysts in the range of 150 - 200 g/ft3. Under stoichiometric conditions, 500 °C can be met in many engine operating points however, for lean operating applications, the exhaust temperature can be significantly lower than 500 °C posing a significant challenge for exhaust catalytic CH4 control. This paper will discuss synthetic gas reactor study results using ozone in the feed gas to perform low temperature methane control. A range of catalysts were characterised for the development of low temperature methane control and a non-precious metal catalyst was found to give high efficiency at low temperatures. The best catalyst screened did not contain PGM and was a current production catalyst that gave >60% CH4 control at 220 °C, in the presence of water. All other catalysts screened gave no significant methane control activity at low temperatures. The feed gas composition played a key role in the peak efficiency obtained. The data shows a significant improvement in ozone enhanced catalysis compared to more traditional precious metal based CH4 control routes.
Keenan, Matthew, Nicole, Jacques, Poojary, Damodara
Polycyclic Aromatic Hydrocarbons in Diesel Engine Exhaust Both with and without Aftertreatment2018-01-18129/10/2018
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 Engine2018-01-17309/10/2018
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
Severe Soot Oxidations in Gasoline Particulate Filter Applications2018-01-16999/10/2018
With the start of EU6 in 2017 gasoline particulate filters (GPF) have been introduced to production vehicles. It is expected that by 2019 all gasoline direct injection engines sold in Europe will be equipped with a GPF. A similar trend is observed in China with a slight delay compared to Europe, but covering all gasoline engines, including those with port fuel injection technology. With the introduction of GPFs, new requirements are introduced to the management of gasoline engines and their aftertreatment. One requirement is to protect the aftertreatment components from excessive temperatures and damage as result of uncontrolled soot oxidations. While the general fundamentals are similar to those in diesel applications, significant differences exist in the relevant details. In gasoline applications, for example, one of the worst case scenarios with respect to severe soot oxidations is a fuel cutoff during which oxygen is introduced, whereas the drop to idle, critical in diesel applications, is not of concern. In this contribution, we will evaluate the sensitivity of the soot oxidation in gasoline particulate filters to various operating parameters. We will discuss results obtained by a combination of a broad set of data from fuel cutoff experiments performed on engine bench under different operating conditions as well as detailed numerical simulations. Different limiting cases and regimes as well as simplified methods to describe them will be introduced and discussed. The results will be relevant for developing software functionalities to manage the soot, to protect the filter component as well as for calibrations.
Boger, Thorsten, Rose, Dominik, Nicolin, Per, Coulet, Bertrand, Bachurina, Anastasiia
Effects of Soot Deposition on NOx Purification Reaction and Mass Transfer in a SCR/DPF Catalyst2018-01-17079/10/2018
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 Oil2018-01-17609/10/2018
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 Filters2018-01-17039/10/2018
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 Filters2018-01-17049/10/2018
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
Diffusion Supporting Passive Filter Regeneration- A Modeling Contribution on Coated Filters2018-01-09574/3/2018
Wall flow particulate filters have been used as a standard exhaust aftertreatment device for many years. The interaction of particulate matter (PM) regeneration and catalytically supported reactions strongly depends on the given operating conditions. Temperature, species concentration and mass flow cause a change from advective to diffusive-controlled flow conditions and influence the rate controlling dominance of individual reactions. A transient 1D+1D model is presented considering advective and diffusive transport phenomena. The reaction scheme focuses on passive PM conversion and catalytic oxidation of NO. The model is validated with analytical references. The impact of back-diffusion is explored simulating pure advective and combined advective diffusive species transport. Rate approaches from literature are applied to investigate PM conversion at various operating conditions. Spatial NO/NO2 profiles over the cake/wall height and length are discussed and the transient evolution of axial cake heights is presented. The results reveal that the impact of back-diffusion on PM cake conversion cannot be purely assessed by the Péclet number. The comparison of different spatial coating designs shows that front-end coatings feature superior performance in passive PM cake conversion.
Wurzenberger, Johann C., Triebl, Christoph, Kutschi, Susanne
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 Model2018-01-09644/3/2018
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
1D Engine Simulation Approach for Optimizing Engine and Exhaust Aftertreatment Thermal Management for Passenger Car Diesel Engines by Means of Variable Valve Train (VVT) Applications2018-01-01634/3/2018
Using a holistic 1D engine simulation approach for the modelling of full-transient engine operation, allows analyzing future engine concepts, including its exhaust gas aftertreatment technology, early in the development process. Thus, this approach enables the investigation of both important fields - the thermodynamic engine process and the aftertreatment system, together with their interaction in a single simulation environment. Regarding the aftertreatment system, the kinetic reaction behavior of state-of-the-art and advanced components, such as Diesel Oxidation Catalysts (DOC) or Selective Catalytic Reduction Soot Filters (SCRF), is being modelled. Furthermore, the authors present the use of the 1D engine and exhaust gas aftertreatment model on use cases of variable valve train (VVT) applications on passenger car (PC) diesel engines. The VVT applications consider a wide range of variables such as exhaust cam phasing, late intake valve opening, Miller, 2nd exhaust event and cylinder deactivation. The model has been validated with the results of experimental investigations to do this in a first step. Secondly, the VVT applications are implemented to the model to analyze their heating potential according to an efficient engine and exhaust gas thermal management. Various heating strategies have been investigated for a full-size vehicle within extended engine speed and load ranges which are relevant for the Worldwide Harmonized Light Vehicles Test Cycle (WLTC) and even more for the determination of Real Driving Emissions (RDE). The results are compared to a conventional heating measure to demonstrate the potential in terms of a faster aftertreatment light-off with increased conversion efficiencies and benefits in CO2 emissions. As conclusion out of the investigations it can be seen, that a cylinder deactivation or a second exhaust event could provide up to 5-10% CO2 reduction under RDE conditions that comply with the EU6d legislation limit.
Deppenkemper, Kai, Özyalcin, Can, Ehrly, Markus, Schoenen, Markus, Bergmann, Dirk, Pischinger, Stefan
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
Revisiting the Single Equation Pressure Drop Model for Particulate Filters2018-01-09524/3/2018
Particulate filters (PF) are a highly effective after-treatment device that reduces particulate matter emissions, a rising environmental concern in the automotive industry. However, accumulation of solid particles during the PF filtration process increases engine backpressure considerably, which can have a negative impact on engine efficiency, acoustics, and gaseous emissions. In this area, an accurate pressure drop model helps to better understand the effect of accumulated solid particles in the PF on engine backpressure, aiding in design and regeneration considerations without physical testing. These effects are further improved on board the vehicle using a single equation pressure drop model with a relatively low computational cost. This article presents a thorough history of PF pressure drop models and their advancements. Specifically, this review highlights that numerous authors have derived single pressure drop equations for dynamically incompressible flow and several have formulated models for compressible flow. Then, this effort builds on this history by presenting a revised single equation PF pressure model derived for pseudo-compressible flow. This updated model improves the predictions under varying PF temperature profiles when compared to dynamically incompressible flow. As a result, computation of the pressure drop for non-isothermal flow is now possible via a single algebraic equation, reducing computational costs in comparison to the previous compressible numerical approaches.
Depcik, Christopher, Spickler, Bailey, Gaire, Anmesh
Development of Improved SCRonDPF Design for Future Tighter Regulations and Reduced System Packaging2018-01-03444/3/2018
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
Impacts of Drive Cycle and Ambient Temperature on Modelled Gasoline Particulate Filter Soot Accumulation and Regeneration2018-01-09494/3/2018
Gasoline particulate filters (GPF) are used as an efficient solution to reduce particulate matter (PM) emissions on gasoline vehicles. GPFs are ceramic wall-flow filters and are normally located downstream of conventional three-way catalysts (TWC) [1]. The study in this paper is intended to evaluate the impact of drive cycle and ambient temperature on modelled GPF soot accumulation and regeneration. The test data were obtained through real road testing in Chinese cities including Nanjing, Hainan and Harbin. Five 2.0 L gasoline turbo direct-injection (GTDI) prototype vehicles from several China Stage 6 applications were employed for the road tests. The results of the testing indicated that a drive cycle with low engine speed and engine load, like a typical city road in rush hour traffic in Nanjing, had a low probability of generating high GPF temperatures (> 600 °C) and sufficient oxygen to regenerate the GPF. However, the soot accumulation model performed as expected [2] and the soot regeneration model demonstrated sufficient opportunity to oxidize soot prior to excessive soot accumulation, even under the limited city drive cycle conditions. Ambient temperatures during cold engine starts played a significant role in the amount of modeled soot being generated during any given drive cycle. Considerably more soot was generated during cold starts at low ambient conditions (< 0 °C) due to the increase in fuel mass and the use and duration of compression injection to aid in catalyst heating.
Yue, Hongchao, Lehmen, Allen, Van Nieuwstadt, Michiel, Mason, Gregory, Barwick, Matt, Warm, David, Pebley, Kirk
Solid Particle Number and Mass Emissions from Lean and Stoichiometric Gasoline Direct Injection Engine Operation2018-01-03594/3/2018
In this work, engine-out particle mass (PM) and particle number (PN) emissions were experimentally examined from a gasoline direct injection (GDI) engine operating in two lean combustion modes and one stoichiometric mode with a fuel of known properties. Ten steady state operating points, two constant speed load steps, and an engine cold start were examined. Results showed that solid particles emitted from the engine under steady state stoichiometric conditions had a uniquely broad size distribution that was relatively flat between the diameters of 10 and 100 nm. In most operating conditions, lean homogenous modes can achieve lower particle emissions than stoichiometric modes while improving engine thermal efficiency. Alternatively, lean stratified operating modes resulted in significantly higher PN and PM emissions than both lean homogeneous and stoichiometric modes with increased efficiency only at low engine load. Stoichiometric load steps showed minimal soot emissions while ash-mode emissions spike dramatically due to oil consumption caused by piston ring adjustment. Correlation of PN to PM for steady state stoichiometric cases was in good agreement with that reported from multiple prior studies for both diesel and stoichiometric GDI engines. However, the lean cases resulted in higher PN to PM ratios indicating more small particles per unit mass. High ash particle concentration, especially in lean operation illustrates that oil control is important for mitigating impacts on downstream gasoline particulate filters (GPF) from which ash particles are cannot be removed during filter regeneration. Further research is necessary to elucidate the origin and composition of sub-23 nm particles from GDI engines and their effect on aftertreatment technology if lean homogeneous modes are to be employed.
Bock, Noah, Jeon, Joonho, Kittelson, David, Northrop, William F.
The Effect of Swirl on the Flow Uniformity in Automotive Exhaust Catalysts2017-01-238410/8/2017
In aftertreatment system design, flow uniformity is of paramount importance as it affects aftertreatment device conversion efficiency and durability. The major trend of downsizing engines using turbochargers means the effect of the turbine residual swirl on the flow needs to be considered. In this paper, this effect has been investigated experimentally and numerically. A swirling flow rig with a moving-block swirl generator was used to generate swirling flow in a sudden expansion diffuser with a wash-coated diesel oxidation catalyst (DOC) downstream. Hot-wire anemometry (HWA) was used to measure the axial and tangential velocities of the swirling flow upstream of the diffuser expansion and the axial velocity downstream the monolith. With no swirl, the flow in the catalyst monolith is highly non-uniform with maximum velocities near the diffuser axis. At high swirl levels, the flow is also highly nonuniform with the highest velocities near the diffuser wall. An intermediate swirl level exists where the flow is most uniform. To gain further insight into the mechanisms controlling flow redistribution, numerical simulations have been performed using the commercial CFD code STARCCM+. With no swirl, the central jet transverses the diffuser, and a drastic flow redistribution takes place near the monolith face due to its high resistance. Immediately downstream of the sudden expansion, the flow separates from the diffuser wall forming a separation zone around the central jet. Increasing swirl reduces the size of this separation zone, and eventually leads to the formation of the central recirculation zone characteristic of high swirl flows. At intermediate swirl levels, the size of the wall separation zone is reduced considerably, while the axial adverse pressure gradient is insufficient to cause a central recirculation. Such a flow regime occurs at relatively low swirl levels (S ~ 0.23). This may have positive implications for aftertreatment system design with low residual swirl levels from the turbine, which might be tuned by adjusting the distance between the turbine and the catalyst or employing guide vanes. The findings can be directly transferred to other aftertreatment systems with a catalyst or particulate filter. Moreover, swirling flows with an obstruction or a high resistance device downstream (e.g. a heat exchanger or filter) are present in many other applications such as cooling flows, combustion and turbomachinery. Therefore the results are relevant to a much wider research and industrial community.
Rusli, Ijhar H., Aleksandrova, Svetlana, Medina, Humberto, Benjamin, Stephen F.
Simultaneous Measurement of Fuel Droplet Deposition Amount and Oil Film Thickness on Spray Impingement Using Double Laser Induced Fluorescence Method2017-01-237110/8/2017
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 Engines2017-01-237210/8/2017
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
Catalyzed Gasoline Particulate Filter (GPF) Performance: Effect of Driving Cycle, Fuel, Catalyst Coating2017-01-236610/8/2017
Because of the increased use of gasoline direct engine (GDI) in the automobile industry, there is a significant need to control particulates from GDI engines based on emission regulations. One potential technical approach is the utilization of a gasoline particulate filter (GPF). The successful adoption of this emission control technology needs to take many aspects into consideration and requires a system approach for optimization. This study conducted research to investigate the impact of vehicle driving cycles, fuel properties and catalyst coating on the performance of GPF. It was found that driving cycle has significant impact on particulate emission. Fuel quality still plays a role in particulate emissions, and can affect the GPF performance. Catalyzed GPF is preferred for soot regeneration, especially for the case that the vehicle operation is dominated by congested city driving condition, i.e. low operating temperatures. The details of the study are presented in the paper.
Xia, Wenzheng, Zheng, Yi, He, Xiaokun, Yang, Dongxia, Shao, Huifang, Remias, Joesph, Roos, Joseph, Wang, Yinhui
Diesel Oxidation Catalyst and HC Investigations of a Low RON Gasoline Fuel in a Compression Ignition Engine2017-01-240510/8/2017
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 Programming2017-01-218510/8/2017
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
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