Browse Topic: Catalytic converters

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Performance Optimization of an Exhaust System for 4 Cylinder Engine by Implementation of Computational Fluid Dynamics, Acoustic and Thermal Analysis2022-01-076503/29/2022
The engine system requirements have changed from being focused only on delivering engine power to now having to meet environmental emission standards. The exhaust system collects exhaust gases from the combustion cylinders, eliminates dangerous pollutants, decreases noise, and discharges the purified exhaust gases at a safe distance from the vehicle's occupants. Designs of lightweight models for exhausts were always aimed at using newer lighter materials. As the design of an exhaust is more or less fixed, this approach is hardly profitable anymore. The most important components of an exhaust system are the exhaust manifold, the catalytic converter, the muffler, the resonator and connecting all of them together are connecting exhaust pipes. In this paper, the optimization of the various elements of 4 cylinder 1.8L engine exhaust system is carried out with the help of analysis software ANSYS 19.2 workbench, by performing ‘Steady State Thermal Analysis’, ‘Acoustic Analysis’ and simulating
Aiyan, Mohammed, Sagar, S Sumanth, Raghav S, Sanjay
Investigations of Process and Component Parameters for the Number of Particles and Size Distribution of a Supercharged DI-SI Engine2022-01-070003/29/2022
Due to the short mixture formation times in the direct injection of modern gasoline engines, there is an increase in the emission of undesirable particle emissions in gasoline engines. As a result of previous studies with a portable emission measurement system (PEMS) of raw emissions and cleaned emissions, the particle number (PN) of the sampling point after the catalyst was higher than before the catalyst at the same process parameters and engine operating points. Based on this reproducible phenomenon, several theories were proposed. The theories set up dealt on the one hand with the question of process control with regard to the formation of particles, but also fundamentally with the question of whether conventional exhaust gas aftertreatment systems (3-way catalytic converters) are suitable for influencing the number of particles. In addition, studies of the oil consumption via the blow-by system and its influence on particle emissions also played a role. To verify these theories
Dost, Tobias, Schambach, Ricardo, Getzlaff, Joern
Performance Optimisation of an Exhaust System for 4 Cylinder Engine by Implementation of Computational Fluid Dynamics, Acoustic and Thermal Analysis2022-01-067703/29/2022
The engine system requirements have changed from being focused only on delivering engine power to now having to meet environmental emission standards. The exhaust system collects exhaust gases from the combustion cylinders, eliminates dangerous pollutants, decreases noise, and discharges the purified exhaust gases at a safe distance from the vehicle's occupants. Designs of lightweight models for exhausts were always aimed at using newer lighter materials. As the design of an exhaust is more or less fixed, this approach is hardly profitable anymore. The most important components of an exhaust system are the exhaust manifold, the catalytic converter, the muffler, the resonator and connecting all of them together are connecting exhaust pipes. In this paper, the optimization of the various elements of 4 cylinder 1.8L engine exhaust system is carried out with the help of analysis software ANSYS 19.2 workbench, by performing ‘Steady State Thermal Analysis’, ‘Acoustic Analysis’ and simulating
Aiyan, Mohammed, Raghav S, Sanjay, Sagar, S Sumanth
Regulatory Norms and effect on transmission component validation2021-26-046009/22/2021
With the advent of BS VI regulations, automotive manufacturers are required to innovate the powertrains, fuel systems, exhaust and its after treatment systems to meet the regulatory requirements. The exhaust regulations can be met either by reducing the exhaust gases being generated by the engine (attacking the source) or by treating the exhaust gases in after treatment devices. The choice of the opted system varies with the manufacturer. The after-treatment devices such as catalytic converters are generally mounted in the engine compartment to take advantage of high temperature of exhaust gases to yield the reactions. Such an arrangement imposes a lot of thermal load on the peripheral components such as gearshift cables, bearings, oil seals, driveshafts etc. Thermal shields or thermal sleeve are used to address thermal issue and to protect transmission components. System level validation test requirement of transmission need to be re-visited to considering change in environmental
Tongaonkar, Yogesh Manohar, Patel, Hiral, Tendulkar, Vishveshvar, Bhosale, Vikas, halingale, Amol
Three-way catalyst model development using physical and machine learning methods for engine control design purposes2021-01-122109/21/2021
Gasoline engine control strategies ensure a combustion control around stoichiometry. That is because the three-way catalytic converter allows CO and HC oxidation under lean operating conditions while ensuring NOx reduction for rich mixtures. In case of engine malfunction, the controller must adapt to compensate for potential torque losse and other critical attributes, potentially leading to significant deviation of the fuel-air mixture richness from stoichiometry and larger emission levels. Therefore, during development of the engine fault diagnostics the impact on the pollutant emissions must be considered. In this paper, a model-based development process is proposed. It is based on system simulation modelling techniques, where a complete exhaust line is represented in order to predict tail-pipe emissions under stoichiometric, lean and rich conditions, for engine control design purposes. Two different modelling approaches are applied and evaluated in this paper. First, a physics-based
LOUSSAIEF, Sana, Akhmetov, Yerlan, GROISIL, Melanie, Takahashi, Daisuke, Kuhara, Masaki, Isobe, Yoshiki, Mas, Peter
An Investigation of Emission Species over a Diesel Oxidation Catalyst Using Flow Reversal Strategy2021-01-060604/06/2021
With the increasing demand of emission reductions from the automotive industry, advanced after-treatment strategies have been investigated to overcome the challenges associated with meeting increasingly stringent emission regulations. Ongoing investigations on low temperature combustion (LTC) strategies are being researched to meet future emission regulations, however, the lowered exhaust temperature presents an even greater issue for exhaust after-treatment due to the change in combustion modes. Catalyst temperature is critical for the catalytic ability to maintain effective conversion efficiency of regulated emissions. The use of periodic flow reversal has shown benefits of maintaining catalyst temperature by alternating the exhaust flow direction through the catalytic converter, reducing the catalyst sensitivity to inlet gas temperature fluctuations. Cyclically alternating the exhaust flow direction can produce a thermal wave, elevating the central catalyst temperature above the
Hesketh, Cavan, Liang, Li, Sandhu, Navjot Singh, Han, Xiaoye, Wang, Meiping, Zheng, Ming
A Study of the Effect of Light-Off Temperatures and Light-Off Curve Shape on the Cumulative Emissions Performance of 3-Way Catalytic Converters2021-01-059404/06/2021
The results of this paper will show the reader how to quantify a minimum light-off temperature to meet the required emissions standards with the use of a 3-way catalytic converter. The method can be applied to both motorcycle and larger automotive catalysts to help meet their respective emissions standards (Euro 5/Euro 7). The ability to predict a light-off temperature for any catalyst at the beginning of the project saves both time and resource. With an emphasis on how the shape of the light-off curve affects the cumulative tailpipe emissions and how shape of the light-off curves change with the ageing process. Changes in the light-off curves will be reviewed to understand how the chemical reactions and pore diffusion mechanisms within the catalyst deplete to negatively affect performance over its life time. Using the total cumulative emissions target to achieve the OBD (On Board diagnostic) requirement along with WMTC data, light-off curves were modelled using predicted catalyst
Mc Grane, Liam, Douglas, Roy, Irwin, Kurtis, Stewart, Jonathan, Woods, Andrew, Muehlstaedt, Fabian
Analysis on Emission Characteristics of Urban Buses Based on Remote Online Monitoring2021-01-060104/06/2021
In this study, a new system of assessment method was developed to evaluate the characteristics of urban buses based on remote online monitoring. Four types of buses, including China V emission standards diesel bus, lean-burn CNG bus, air-fuel equivalence ratio combustion CNG bus and gas-electric hybrid bus, were chosen as samples to analyze the emission characteristics of urban buses with different engine types in urban scenario. Based on the traffic conditions in Beijing, the actual emission characteristics of buses under newly-built driving conditions were analyzed. Moreover, the emission factor database of urban buses in Beijing was established to analyze the characteristics of excess emission. The research results are shown as follows. 1) Compared with other types of buses, NOX emission factor and emission rate of lean-burn CNG bus are much higher. The equivalent air-fuel ratio CNG engine combined with TWC catalytic converter and hybrid power technology can better reduce NOX
Feng, Qian, Zhen, Kai, Lu, Yang, Yang, Xingzi, Yang, Yanyan, Liu, Baoxian, Li, Mengliang, Li, Zhijun
SYMPHONY in the key of C820AUTP10_0310/01/2020
Tenneco and GM solve multiple technical challenges to engineer the mid-engine Corvette's sweet-sounding active exhaust system. Few things in the automotive space are more soul-stirring than the sound of a V8 engine - at wide-open throttle, or top-gear cruising, or at any combination of engine speed and load in between. For Chevrolet Corvette enthusiasts, engine sound quality is Holy Grail stuff. But the Vette's classic roar is just one piece of an aural signature that has grown increasingly sophisticated in the car's last two (C7 and C8) generations. “Exhaust note is part of the Corvette's DNA, but the car also must meet pass-by noise laws and various global-market sound regulations,” observed Dmitri Konson, VP of global clean air engineering at Tenneco, which supplies the complete cold-side exhaust (from the catalytic converter to the exhaust tips) for the 2020 C8 Stingray and components for the LT2 V8. However, acoustics engineering isn't only about numbers and curves, Konson noted
Brooke, Lindsay
Accelerated Ageing Method of Three Way Catalyst Run on Test Bed with Emission Performance and Oxygen Storage Capacity Evaluation2020-01-218909/15/2020
The aim of this paper was to describe a method of accelerated three way catalytic converter (TWC) ageing performed on the engine test bed for European On Board Diagnostics (EOBD) monitoring purposes and screening of different catalysts solutions. To accelerate the catalyst ageing process, the exhaust gas temperature was elevated to a range 1000 - 1200°C, which is typical for an ageing cycle performed using ovens. Catalyst emissions performance was checked at new condition (after degreening) and subsequently at predefined ageing intervals, based on the oxygen storage capacity (OSC) evaluation. The emission tests were performed in the laboratory on the chassis dynamometer using legislative cycles. The accelerated ageing method was found to be of use for verifying the EOBD functionality under vehicle operation with a degraded catalyst substrate. Secondly, the described method allows execution of a time-efficient ageing cycle on a test bed in order to validate catalyst chemistry and
Sala, Rafal, Bielaczyc, Piotr
EDITORIAL: A restart into the unknown20AUTP05_0405/01/2020
The global auto industry is gradually restarting. But going where? The COVID-19 crisis is leaving deep fiscal scars to add to the human toll. Individuals, businesses and even entire economies eventually will recover, but in an auto sector already in the throes of vast structural change, the COVID factor could have a much longer-lasting impact. Maybe not all of it has to be negative.
Visnic, Bill
Engine and Aftertreatment Co-Optimization of Connected HEVs via Multi-Range Vehicle Speed Planning and Prediction2020-01-059004/14/2020
Connected vehicles (CVs) have situational awareness that can be exploited for control and optimization of the powertrain system. While extensive studies have been carried out for energy efficiency improvement of CVs via eco-driving and planning, the implication of such technologies on the thermal responses of CVs (including those of the engine and aftertreatment systems) has not been fully investigated. One of the key challenges in leveraging connectivity for optimization-based thermal management of CVs is the relatively slow thermal dynamics, which necessitate the use of a long prediction horizon to achieve the best performance. Long-term prediction of the CV speed, unlike the short-range prediction based on vehicle-to-infrastructure (V2I) and vehicle-to-vehicle (V2V) communications-based information, is difficult and error-prone. The multiple timescales inherent to power and thermal systems call for a variable timescale optimization framework with access to short- and long-term
Hu, Qiuhao, Amini, Mohammad R., Feng, Yiheng, Yang, Zhen, Wang, Hao, Kolmanovsky, Ilya, Sun, Jing, Wiese, Ashley, Qiu, Zeng, Buckland, Julia
Integration of Sensitivity Analysis and Design for Six Sigma (DFSS) Methodology into Transient Thermal Analysis2020-01-138904/14/2020
In this paper we present an integrated approach which combines analysis of the effect of simultaneous variations in model input parameters on the component or system temperatures. The sensitivity analysis can be conducted by varying model input parameters using specific values that may be of interest to the user. The alternative approach is to use a structured set of parameters generated in the form of DFSS DOE matrix. The matrix represents a combination of simulation conditions which combine the control factors (CF) and noise factors. CF’s are the design parameters that the engineer can modify to achieve a robust design. Noise factors include parameters that are outside the control of the design engineer. In automotive thermal management, noise factors include changes in ambient temperature, exhaust gas temperatures or aging of exhaust system or heat shields for example. The integrated approach, presented in this paper, provides powerful tools that can significantly reduce the total
El-Sharkawy, Alaa, Sami, Amr, Arora, Dipan, Hekal, Abd El-Rahman
Heat Transfer Analysis of Catalytic Converters during Cold Starts2019-24-016309/09/2019
The transient heat transfer behavior of an automotive catalytic converter has been simulated with OpenFOAM in 1D. The model takes into consideration the gas-solid convective heat transfer, axial wall conduction and heat capacity effects in the solid phase, but also the chemical reactions of CO oxidation, based on simplified Arrhenius and Langmuir-Hinshelwood approaches. The associated parameters are the results of data in literature tuned by experiments. Simplified cases of constant flow rates and gas temperatures in the catalyst inflow have been chosen for a comprehensive analysis of the heat and mass transfer phenomena. The impact of inlet flow temperatures and inlet flow rates on the heat up characteristics as well as in the CO emissions have been quantified. A dimensional analysis is proposed and dimensionless temperature difference and space-time coordinates are introduced. Using this suitably modified coordinates, for the case of negligible axial solid conduction, computed solid
Papetti, Viola, Dimopoulos Eggenschwiler, Panayotis, Della Torre, Augusto, Montenegro, Gianluca, Onorati, Angelo, Koltsakis, Grigorios
Optimization of Catalytic Converter Design to Improve Under-Hood Thermal Management2019-01-126304/02/2019
The Catalytic Converter along with the inlet pipe and heat shields are part of the exhaust system that emits powerful heat to the surrounding components. With increasing need for tight under-hood spaces it is very critical to manage the heat emitted by the exhausts that may significantly increase temperature of surrounding components. In this paper a design methodology for catalytic converter has been applied which optimizes the design of the catalytic converter to reduce the surface temperature. The exhaust surface temperature is simulated as a function of time to account for transient effects. The simulation also considers various duty cycles such as road load, city traffic and grade driving conditions. To control the heat output of the exhaust system to the surrounding components different materials and properties of catalytic converter have been considered to reduce radiative heat transfer. The most influential design factors for the catalytic converter which affect the surface
El-Sharkawy, Alaa, Arora, Dipan, Huxford, Michael W.
Water Injection Benefits in a 3-Cylinder Downsized SI-Engine2019-01-003401/15/2019
With progressing electrification of automotive powertrains and demands to meet increasingly stringent emission regulations, a combination of an electric motor and downsized turbocharged spark-ignited engine has been recognized as a viable solution. The SI engine must be optimized, and preferentially downsized, to reduce tailpipe CO2 and other emissions. However, drives to increase BMEP (Brake Mean Effective Pressure) and compression ratio/thermal efficiency increase propensities of knocking (auto-ignition of residual unburnt charge before the propagating flame reaches it) in downsized engines. Currently, knock is mitigated by retarding the ignition timing, but this has several limitations. Another option identified in the last decade (following trials of similar technology in aircraft combustion engines) is water injection, which suppresses knocking largely by reducing local in-cylinder mixture temperatures due to its latent heat of vaporization. Addition of adequate water can lead to
Khatri, Jayesh, Denbratt, Ingemar, Dahlander, Petter, Koopmans, Lucien
Technologies to Achieve Future Emission Legislations with Two Stroke Motorcycles2018-32-004210/30/2018
Increasingly stringent emission regulations force manufacturers of two wheelers to develop low emission motorcycle concepts. Especially for small two-stroke engines with symmetrical port timing structure, causing high HC-emissions due to scavenge losses, this is a challenging demand that can only be met with alternative mixture formation strategies and by intensifying the use of modern development tools. Changing from EU4 to EU5, emission legislation will not only have an impact on the improvement of internal combustion but will also drastically change the after-treatment system. Nowadays, small two-stroke engines make use of a simple carburetor for external mixture preparation. The cylinders are scavenged by air/fuel mixtures. Equipped with exhaust gas after-treatment systems, such as secondary air with two or three catalytic converters, the emission limits for EURO 4 homologation can be achieved with carbureted engines. An increased number of catalytic converters in the exhaust
Oswald, Roland, Kirchberger, Roland, Krimplstatter, Stefan
Emission Reduction during Cold Start by Combustion Controlled Increase of In-Cylinder Temperatures2018-01-174009/10/2018
A significant share of the emissions of a vehicle with internal combustion engine originates from the cold start. In addition to the more stringent limits for particulate emissions due the introduction of the Euro 6c standard for gasoline engines with direct injection (GDI), exhaust gas emission testing is currently performed applying the real driving emission test procedure (RDE) required by the Euro 6d TEMP standard. The RDE test procedure is not clearly defined, potentially allowing high loads immediately after the engine start. Under such circumstances the combustion chamber features low surface temperatures impairing emission performance and in particular provoking the excessive generation of hydrocarbon and particulate emissions. It is therefore important not only to examine the heating of the catalytic converter during the cold start, but also the preconditioning of the combustion chamber itself. This paper describes the influence of different catalytic converter heating
Titus, Fabian, Berlet, Peter, Sobek, Florian, Wessling, Justus
Passive Hydrocarbon Trap to Enable SULEV-30 Tailpipe Emissions from a Flex-Fuel Vehicle on E85 Fuel2018-01-094404/03/2018
Future LEV-III tailpipe (TP) emission regulations pose an enormous challenge forcing the fleet average of light-duty vehicles produced in the 2025 model year to perform at the super ultralow emission vehicle (SULEV-30) certification levels (versus less than 20% produced today). To achieve SULEV-30, regulated TP emissions of non-methane organic gas (NMOG) hydrocarbons (HCs) and oxygenates plus oxides of nitrogen (NOx) must be below a combined 30 mg/mi (18.6 mg/km) standard as measured on the federal emissions certification cycle (FTP-75). However, when flex-fuel vehicles use E85 fuel instead of gasoline, NMOG emissions at cold start are nearly doubled, before the catalytic converter is active. Passive HC traps (HCTs) are a potential solution to reduce TP NMOG emissions. The conventional HCT design was modified by changing the zeolite chemistry so as to improve HC retention coupled with more efficient combustion during the desorption phase. Increased trapping efficiently was achieved by
Lupescu, Jason, Xu, Lifeng, Nunan, John, Alltizer, Chad
Modelling the Variation in Precious Metal Dispersion in a Three Way Catalytic Converter after Aging2018-01-095904/03/2018
With emission legislations becoming ever more stringent, there is an increased pressure on after-treatment systems and more specifically three-way catalysts. With recent developments in emission legislations, there is a requirement for more complex after-treatment systems and understanding of the aging process. Whilst the body of understanding on catalyst deactivation and, in particular, catalyst aging is growing, there are still significant gaps in understanding, particularly how real world variations in temperature, flow rate and gas concentrations affect catalyst behavior. Under normal driving conditions, the catalyst can experience varying oxygen concentrations, such as under heavy acceleration or cruising down a hill will show a variation in oxygen from the engine emissions. The effect that varying oxygen concentrations has on the rate of aging is not fully understood and hence the total deactivation and conversion efficiencies are not known throughout the catalyst lifetime
Irwin, Kurtis, Douglas, Roy, Stewart, Jonathan David, Pedlow, Andrew, Woods, Andrew
Reducing Harmful Emissions of the Vehicular Engine by Rapid After-Start Heating of the Catalytic Converter Using Thermal Accumulator2018-01-078404/03/2018
The article examines the peculiarities of evaluating the vehicular engine harmful emissions in different heating modes when using thermal development system of the catalytic converter within phase-transitional thermal accumulators. The system under review uses thermal energy from different sources of the vehicular engine during its operation to accumulate it in thermal accumulators. The functional scheme of thermal development of the “vehicular engine - thermal accumulator - catalytic converter” system is shown. The functional scheme takes into account fuel consumption, mechanical energy and harmful emissions when operating the vehicular engine equipped with the exhaust gases cleaning system and the thermal development system with phase-transitional thermal accumulator. The article shows main mathematical dependencies to describe the processes of thermal development of the vehicular engine and the catalytic converter when using thermal development system with phase-transitional thermal
Gritsuk, Igor V., Mateichyk, Vasyl, Tsiuman, Mykola, Gutarevych, Yurii, Smieszek, Miroslaw, Goridko, Nataliia
High-Performance Rear- and Mid-Engine Vehicle Exhaust System Temperatures2018-01-143604/03/2018
Hot surface ignition of combustible material is a known cause of vehicle fires. Although the detailed mechanisms of hot surface ignition are highly complex, the surface temperature is known to play a crucial role in this process. There has been limited previous work in the literature on this topic, much of which has focused on engine or exhaust system surface temperatures of the most common types of passenger vehicles. Also, much of this work was done in an unrepeatable manner and suffered from measurement technique induced errors. The focus of the present work is on repeatable and low measurement technique induced error temperature measurements of exhaust system surface temperatures of rear- and mid-engine sports cars. Temperature measurements were made at several points along the exhaust systems of vehicles both with and without turbo chargers on a 5-mile oval track. The exhaust system surface temperatures were examined under conditions of transient acceleration and steady-state
Papageorge, Michael, Colwell, Jeff
Thermo-Mechanical Fatigue Testing of Welded Tubes for Exhaust Applications2018-01-009004/03/2018
Selected ferritic stainless steel sheets for exhaust applications were tested under thermo-mechanical fatigue (TMF) condition in the temperature range of 400-800 °C with partial constraint. Straight welded tubes were used as the testing coupons to withstand large compression without buckling, and to understand the effect of welding as well. Repeated tests confirmed the observed failure scenario for each material type. The hysteresis loop behaviors were also simulated using the mechanism-based integrated creep and fatigue theory (ICFT) model. Although more development work is needed, for quick material screening purpose this type of testing could be a very cost effective solution for materials and tube weld development for exhaust applications.
Quan, Guangchun, Wu, Xijia, Lafleur, Luc, zhang, Zhong
FEA-Based Simulation of Exhaust Hanger Forces2018-01-128804/03/2018
Exhaust systems can be a source of vibrations that transmit inside the vehicle through the exhaust hangers. These vibrations are caused by engine excitations under acceleration. During the upfront development stage, it is important to predict accurately the forces of the exhaust hangers in order to drive a robust exhaust system design and prevent objectionable noise and vibrations inside the vehicle. This paper describes an FEA-based simulation method to predict the exhaust hanger forces. It demonstrates the effect of temperature on the exhaust dynamic behavior and its importance for an accurate prediction of the exhaust hanger forces.
Xu, Zefang, Gummadi, Nagesh, Woytowich, Daniel, Zouani, Abdelkrim
Q&A: Dr. Abhaya Datye, Distinguished Professor, Department of Chemical and Biological Engineering, University of New Mexico, AlbuquerqueTBMG-2870504/01/2018
Researchers at Washington State University, Pacific Northwest National Laboratory, and the University of New Mexico have created a catalyst capable of reducing pollutants at the lower temperatures expected in advanced engines. Their work presents a new way to create a more powerful catalyst while using smaller amounts of platinum — the most expensive component of emission-control catalysts.
Experimental Investigation of Cold Start Emission using Dynamic Catalytic Converter with Pre-Catalyst and Hot Air Injector on a Multi Cylinder Spark Ignition Engine2017-01-236710/08/2017
Control of harmful emissions during cold start of the engine has become a challenging task over the years due to the ever increasing stringent emission norms. Positioning the catalytic converter closer to the exhaust manifold is an efficient way of achieving rapid light-off temperature. On the other hand, the resulting higher thermal loading under high-load engine operation may substantially cause thermal degradation and accelerate catalyst ageing. The objective of the present work is to reduce the light-off time of the catalyst and at the same time reduce the thermal degradation and ageing of the catalyst to the minimum possible extent by adopting an approach with Dynamic Catalytic Converter System (DCCS). The emission tests were conducted at the cold start of a 4 cylinder spark ignition engine with DCCS at different positions of the catalyst at no load conditions. Also emission tests were conducted with pre-catalysts of 20% volume and 40% volume of the main catalytic converter and
Mahadevan, Ganesan, Subramanian, Sendilvelan
An Implementation of CH 4 Kinetic Model with H 2 O into 1-D and 3-D Catalytic Converter Simulation Codes2017-01-238210/08/2017
The diesel dual fuel engine emits CH4 in the exhaust gas. This makes the exhaust gas more difficult to treat comparing to the exhaust gas from the conventional engine since CH4 requires high exhaust temperature to oxidize. In addition, another parameter such as exhaust flow rate, specie concentrations, especially CO, C3H8, and H2O have tremendous impact on Diesel Oxidation Catalyst performance on reducing CH4. This research is aimed to propose a kinetic model based on Langmuir Hinshelwood mechanisms that includes several terms such as CH4, C3H8, CO, O2, and H2O concentrations in order to gain a better understanding on the catalytic reaction and to provide a simulation with an accurate prediction. The model’s kinetic parameters are determined from the experiment by using synthetic gas. The composition of synthetic gas is simulated to be similar to the real exhaust gas from diesel dual fuel engines. By comparing the simulation to the experiment, this kinetic model can give accurate
Suthiprasert, Tul, Jirawongnuson, Sirichai, Wirojsakunchai, Ekathai, Aroonsrisopon, Tanet, Wannatong, Krisada, Salee, Atsawin
Self-Healing, Self-Lubricating TribofilmTBMG-2769710/01/2017
Tribologists have developed a diamond-like film that is generated by the heat and pressure of an automotive engine. The ultra-durable, self-lubricating tribofilm — a film that forms between moving surfaces — can be made to develop self-healing, diamondlike carbon (DLC) tribofilms. The film generates itself by breaking down the molecules of the lubricating oil, and can regenerate the tribofilm as it is worn away.
Dynamic Misfire Threshold Determination Based On Zone-Level and Buffer-Level Adaptations for Internal Combustion Engines2017-01-059903/28/2017
Misfire is generally defined as be no or partial combustion during the power stroke of internal combustion engine. Because a misfired engine will dramatically increase the exhaust emission and potentially cause permanent damage to the catalytic converters, California Air Resources Board (CARB), as well as most of other countries’ on-board diagnostic regulations mandates the detection of misfire. Currently almost all the OEMs utilize crankshaft position sensors as the main input to their misfire detection algorithm. The detailed detection approaches vary among different manufacturers. For example, some chooses the crankshaft angular velocity calculated from the raw output of the crankshaft positon sensor as the measurement to distinguish misfires from normal firing events, while others use crankshaft angular acceleration or the associated torque index derived from the crankshaft position sensor readings as the measurement of misfire detection. Regardless which measurement is chosen, an
Guo, Yichao
Development of a New Ceramic Substrate with Gas Flow Control Functionality2017-01-091903/28/2017
Emission regulations in many countries and regions around the world are becoming stricter in reaction to the increasing awareness of environment protections, and it has now become necessary to improve the performance of catalytic converters to achieve these goals. A catalytic converter is composed of a catalytically active material coated onto a ceramic honeycomb-structured substrate. Honeycomb substrates play the role of ensuring intimate contact between the exhaust gas and the catalyst within the substrate’s flow channels. In recent years, high-load test cycles have been introduced which require increased robustness to maintain low emissions during the wide range of load changes. Therefore, it is extremely important to increase the probability of contact between the exhaust gas and catalyst. To achieve this contact, several measures were considered such as increasing active sites or geometrical surface areas by utilizing substrates with higher cell densities or larger volumes. These
Yoshida, Takeru, Suzuki, Hiromasa, Aoki, Yuki, Hayashi, Naohiro, Ito, Kenichi
Simulation of a Three-Way Catalyst Using Transient Single and Multi-Channel Models2017-01-096603/28/2017
The three-way catalytic converter (TWC) is the most common catalyst for gasoline engine exhaust gas after treatment. The reduction of carbon monoxide (CO), nitrogen oxides (NOx) and unburned hydrocarbons (HC) is achieved via oxidation of carbon monoxide and hydrocarbons, and reduction of nitrogen oxides. These conversion effects were simulated in previous works using single-channel approaches and detailed kinetic models. In addition to the single-channel model multiple representative catalyst channels are used in this work to take heat transfer between the channels into account. Furthermore, inlet temperature distribution is considered. Each channel is split into a user given number of cells and each cell is treated like a perfectly stirred reactor (PSR). The simulation is validated against an experimental four-stroke engine setup with emission outputs fed into a TWC. Next to the transient emissions the temperature progress is simulated in order to model the catalyst’s light off
Aslanjan, Jana, Klauer, Christian, Perlman, Cathleen, Günther, Vivien, Mauss, Fabian
Model Based Control of a Three-way Catalytic Converter Based on the Oxygen Storage Level of the Catalyst2017-01-096003/28/2017
Traditionally, a three-way catalyst (TWC) is controlled to a set heated exhaust gas oxygen (HEGO) sensor voltage (typically placed after the monitored catalyst) that corresponds to optimal catalyst efficiency. This limits the control action, as we rely on emissions breakthrough at the HEGO sensor to infer the state of catalyst. In order to robustly meet the super ultra-low emission regulations, a more precise TWC control around the oxidation level of catalyst is desirable. In this work, we developed a comprehensive set of models to predict the oxygen storage capacity using measured in-vehicle signals only. This is accomplished by developing three models; the first model is a linear in parameter regression model to predict the feed gas emissions from measured signals like engine speed and air-to-fuel ratio (A/F). The second model is a low-dimensional physics based model of the three-way catalyst to predict the exhaust emissions and oxidation state of the catalyst. The third model
Kumar, Pankaj, Makki, Imad
Three-Way Catalyst Diagnostics and Prognostics Based on Support Vector Machines2017-01-097503/28/2017
A three-way catalytic converter (TWC) is an emissions control device, used to treat the exhaust gases in a gasoline engine. The conversion efficiency of the catalyst, however, drops with age or customer usage and needs to be monitored on-line to meet the on board diagnostics (OBD II) regulations. In this work, a non-intrusive catalyst monitor is developed to diagnose the track the remaining useful life of the catalyst based on measured in-vehicle signals. Using air mass and the air-fuel ratio (A/F) at the front (upstream) and rear (downstream) of the catalyst, the catalyst oxygen storage capacity is estimated. The catalyst capacity and operating exhaust temperature are used as an input features for developing a Support Vector Machine (SVM) algorithm based classifier to identify a threshold catalyst. In addition, the distance of the data points in hyperspace from the calibrated threshold plane is used to compute the remaining useful life left. To further improve the monitor robustness
Kumar, Pankaj, Makki, Imad
Vehicle Fires Resulting from Hot Surface Ignition of Grass and Leaves2017-01-135403/28/2017
One potential fire ignition source in a motor vehicle is the hot surfaces on the engine exhaust system. These hot surfaces can come into contact with combustible and flammable liquids (such as engine oil, transmission fluid, brake fluid, gasoline, or Diesel fuel) due to a fluid leak, or during a vehicle collision. If the surface temperature is higher than the hot surface ignition temperature of the combustible or flammable liquid in a given geometry, a fire can potentially ignite and propagate. In addition to automotive fluids, another potential fuel in post-collision vehicle fires is grass, leaves, or other vegetation. Studies of hot surface ignition of dried vegetation have found that ignition depends on the type of vegetation, surface temperature, duration of contact, and ambient conditions such as temperature and wind speed. Ignition can occur at surface temperatures as low as 300 °C, if the vegetation is in contact with the surface for 10 minutes or longer. At surface temperatures
Morse, Timothy, Cundy, Michael, Kytomaa, Harri
Methodology for the Effective Stabilization of Tin-Oxide-Based Oxidation/Reduction CatalystsTBMG-2634902/01/2017
NASA Langley researchers, in work spanning more than a decade, have developed a portfolio of technologies for low-temperature gas catalysis. Originally developed to support space-based CO2 lasers, the technology has evolved into an array of performance capabilities and processing approaches, with potential applications ranging from indoor air filtration to automotive catalytic converters and industrial smokestack applications. The technology has been used commercially in systems that provide clean air to racecar drivers, as well as incorporated into commercially available filtration systems for diesel mining equipment. Backed with extensive research on these technologies, NASA welcomes interest in the portfolio for other commercial and industrial applications.
Development of High-Performance 25 cm 3 Two-Stroke SI Engine for Light Weight Arborist-Chainsaw2016-32-004911/08/2016
A new air-cooled SI two-stroke gasoline engine has been developed for an arborist-chainsaw. This engine has a displacement of 25 cm3 and generates about 1.1 kW and complies with the latest CARB and EPA exhaust regulations by optimizing scavenging flows and the use of a catalytic converter. Characteristics of lightweight, compact and high power-to-weight ratio are required for handheld chainsaws, especially for arborist chainsaws. As a matter of course, these characteristics are needed for engine itself in order to satisfy such market requirements for hand-held power equipment. To realize lightweight and compact design, the placement of catalytic converter is optimized for the engine and a two-piece crankshaft is adopted. Moreover, as preliminary studies, computer analyses such as CFD simulations of in-cylinder flow and cooling air flow, boundary pressure of piston surface during piston movement were performed to estimate output power, short circuit losses of fuel-air mixture, engine
Eto, Kuniyoshi, Nozawa, Masaru, Nara, Masato, Kobayashi, Buhei, Shibasaki, Daiki, Shirai, Ken
Vehicle and Drive Cycle Simulation of a Vacuum Insulated Catalytic Converter2016-01-096704/05/2016
A GT-SUITE vehicle-aftertreatment model has been developed to examine the cold-start emissions reduction capabilities of a Vacuum Insulated Catalytic Converter (VICC). This converter features a thermal management system to maintain the catalyst monolith above its light-off temperature between trips so that most of a vehicle’s cold-start exhaust emissions are avoided. The VICC thermal management system uses vacuum insulation around the monoliths. To further boost its heat retention capacity, a metal phase-change material (PCM) is packaged between the monoliths and vacuum insulation. To prevent overheating of the converter during periods of long, heavy engine use, a few grams of metal hydride charged with hydrogen are attached to the hot side of the vacuum insulation. The GT-SUITE model successfully incorporated the transient heat transfer effects of the PCM using the effective heat capacity method. A variety of conventional, stop-start and hybrid electric vehicles have been simulated
Daya, Rohil, Hoard, John, Chanda, Sreedhar, Singh, Maneet
Design of Catalytic Devices by Means of Genetic Algorithm: Comparison Between Open-Cell Foam and Honeycomb Type Substrates2016-01-096504/05/2016
Metallic foams or sponges are materials with a cell structure suitable for many industrial applications, such as reformers, heat catalytic converters, etc. The success of these materials is due to the combination of various characteristics such as mechanical strength, low density, high specific surface, good thermal exchange properties, low flow resistance and sound absorption. Different materials and manufacturing processes produce different type of structure and properties for various applications. In this work a genetic algorithm has been developed and applied to support the design of catalytic devices. In particular, two substrates were considered, namely the traditional honeycomb and an alternative open-cell foam type. CFD simulations of pressure losses and literature based correlations for the heat and mass transfer were used to support the genetic algorithm in finding the best compromise between flow resistance and pollutant abatement. The CFD analysis was conducted by means of
Falfari, Stefania, Micci, Giacomo, Bianchi, Gian Marco, Brusiani, Federico, Montenegro, Gianluca, Della Torre, Augusto, Onorati, Angelo
Experimental and Numerical Analysis for a Urea-SCR Catalytic Converter2016-01-097304/05/2016
Urea-SCR (Selective Catalytic Reduction) systems are getting a lot of attention as the most promising NOx reduction technology for heavy-duty diesel engine exhaust. In order to promote an effective development for an optimal urea-SCR after-treatment system, it is important to clarify the decomposition behavior of the injected urea and a detailed reaction chemistry of the reactants on the catalyst surface in exhaust gases. In this paper we discuss experimental and numerical studies for the development of a numerical simulation model for the urea-SCR catalyst converter. As a first step, in order to clarify the behavior of reductants in an urea-SCR converter, two types of diagnostic technique were developed; one is for measuring the amount of NH3, and the other is for measuring the amount of total reductants including unreacted urea and iso-cyanic acid. These techniques were applied to examine the behavior of reductants at the inlet and inside the SCR converter. This revealed i) urea to
Yamauchi, Takafumi, Takatori, Yoshiki, Fukuda, Koichiro, Maruyama, Masatoshi
Optimal Energy and Emission Management of a Diesel Hybrid Electric Vehicle Equipped with a Selective Catalytic Reduction System2015-24-254809/06/2015
This paper deals with the problem of obtaining the optimal energy and emission management strategy for a diesel hybrid electric vehicle. The vehicle is assumed to be equipped with a selective catalytic reduction device for the removal of harmful NOx emissions. The authors present a model-based procedure: The energy flows of the hybrid vehicle are modelled in a standard way, while the engine-out emissions are calculated based on a temperature-corrected engine map. For the simulation of the SCR system a combination of two existing first-principle physical models is used. The optimal energy and emission strategy for a given driving cycle is then obtained using dynamic programming. In terms of results, three case studies are presented. One case study illustrates the trade-off between fuel consumption and tailpipe NOx emissions for various relative weights of these objectives. The second case study investigates the influence of the size of the SCR system on fuel consumption and tailpipe NOx
Tschopp, Florian, Nüesch, Tobias, Wang, Mu, Onder, Christopher
Development of Alternate Split Cat-Con - Muffler Configuration Solution for Front Engine Low Floor Bus2015-01-231106/15/2015
Development of split Catalytic Converter (Cat-Con)-Muffler system was done to be used in front engine low floor (FELF) Bus from perspective of cost saving, modularity and reduction in complexity. This system is developed as an alternate to an existing solution of integrated Cat-Con and muffler. The paper describes the development of a split Cat-Con and muffler exhaust system for a FELF Bus, so as to meet cost and time considerations. The development also had to achieve a feasible solution, which could be installed within the packaging volume of the existing configuration of FELF while meeting the regulatory requirements [1] for Pass by noise (PBN), and at the same time conforming to backpressure limits set for optimum engine performance. Multiple design - prototypes - test iterations were carried out to meet the PBN and back pressure target for FELF Bus. The final solution was developed which achieved both the requirements within the specified space constraints. Solution is based on
Palsule, Aditya, Budama, Arun, Somasundaraeswer, Nandakumar
High Porosity Substrates for Fast-Light-Off Applications2015-01-100904/14/2015
Regulations that limit emissions of pollutants from gasoline-powered cars and trucks continue to tighten. More than 75% of emissions through an FTP-75 regulatory test are released in the first few seconds after cold-start. A factor that controls the time to catalytic light-off is the heat capacity of the catalytic converter substrate. Historically, substrates with thinner walls and lower heat capacity have been developed to improve cold-start performance. Another approach is to increase porosity of the substrate. A new material and process technology has been developed to significantly raise the porosity of thin wall substrates (2-3 mil) from 27-35% to 55% while maintaining strength. The heat capacity of the material is 30-38% lower than existing substrates. The reduction in substrate heat capacity enables faster thermal response and lower tailpipe emissions. The reliance on costly precious metals in the washcoat is demonstrated to be lessened. The microstructure of the new substrate
Tanner, Cameron W., Twiggs, Kenneth, Tao, Tinghong, Bronfenbrenner, David, Matsuzono, Yoshiaki, Otsuka, Shinichiro, Suehiro, Yukio, Koyama, Hiroshi
Influence of Linear and Parabolic Elements in Structural Rigidity of Converter Mounting Brackets2015-01-132604/14/2015
Generation of discretization with prescribed element sizes are adapted to the geometry. From the rules of thumb, for a complicated geometry it is important to select the reasonable element order, shapes and size for accurate results. In order to that, this paper describes the influence of elemental algorithm of the catalytic converter mounting brackets. Brackets are main source of mounting of various systems mainly intake and exhaust in the engine. In hot end exhaust system, a bracket design plays a vital role because it has to withstand heavy structural vibrations without isolation combined with thermal loads. Bracket design and stiffness determines the whole catalytic converter system's rigidity. So, here discretization of converter brackets by linear and parabolic elements is studied with different elements types and compared. The study shows disparity in the structural accuracies of the brackets in each of elemental orders respect to the element shapes i.e. in the stiffness and
Rajadurai, Sivanandi, Mani, Guru Prasad, Raja, Kavin, Mohan, Sundaravadivelu
Development of a Target Sensitivity Function based A/F F/B Controller by Sensor Response Characteristics2015-01-163104/14/2015
Recently, automotive emission regulations are being further tightened, such as the Tier III/LEV III in the U.S. As a result, reducing cost of after-treatment systems to meet these strict regulations has become an urgent issue, and then the demand for high-precision air-fuel ratio (A/F) control which can achieve this cost reduction is high [1]. On the other hand, in order to meet rapidly changing market needs, it is becoming difficult to keep enough development periods that enable sufficient calibration by trial-and-error, such as feedback-gain calibration. This leads to an increase in three-way catalytic converter costs in some cases. For these reasons, it is necessary to construct control system that can make full use of hardware capabilities, can shorten development periods regardless of the skill level of engineers. A new robust control method is accomplished in this study, which can provide optimal performance in accordance with the Universal Exhaust Gas Oxygen (UEGO) sensor
Tani, Michinori, Miyauchi, Atsuhiro, Matsuzono, Yoshiaki
Assessment and Experimental Validation of a 3D Acoustic Model of a Motorcycle Muffler2014-32-012211/11/2014
The intake and exhaust lines provide the main abatement of the acoustic emissions of an Internal Combustion Engine (ICE). Many different numerical approaches can be used to evaluate the acoustic attenuation, which is commonly expressed by the Transmission Loss. One-dimensional (1D) and three-dimensional (3D) simulations are conventionally carried out only considering the acoustic domain of the muffler or of the air-box. The walls of the acoustic filter are considered fully rigid and the interaction between the acoustic waves and the structure is consequently negligible. Moreover, the effect of the manufacturing characteristics and the attenuation of the acoustic waves due to the fluid viscous-thermal effects are also commonly disregarded in the numerical analysis of the filters. In addition, the presence of a catalytic converter or a filter cartridge may have an influence on the numerical results. All these aspects, however, can remarkably affect the matching between simulations and
Fioravanti, Andrea, Lenzi, Giulio, Vichi, Giovanni, Ferrara, Giovanni, Ricci, Stefano, Bagnoli, Leonardo
Strategies for Emission Reduction on Small Capacity Two-Wheelers with Regard to Future Legislative Limits2014-32-003111/11/2014
Looking at upcoming emission legislations for two-wheelers, it is quite obvious that the fulfilment of these targets will become one of the biggest challenges within the engine development process. The gradual harmonization of emission limits for two-wheelers with existing automotive standards will subsequently lead to new approaches regarding mixture preparation and exhaust gas aftertreatment. Referring to these future scenarios, a state-of-the-art in development of catalytic converters for two- or three-wheeler applications should be presented. After choosing a suitable test carrier, which has already been equipped with EFI components including an oxygen sensor for λ=1 operation mode, a basic injection system calibration was used to optimize the combustion process. Based on this setup, a variable exhaust system was manufactured to be able to integrate different catalyst configurations. To improve cold start characteristics, the position of the lambda probe and the catalyst were
Tromayer, Juergen, Neumann, Gerd, Bonifer, Marcus, Kiemel, Rainer
Development of a Miller Cycle Powersports Engine2014-32-009011/11/2014
Operation of snowmobiles in national parks is restricted to vehicles meeting the Best Available Technology standard for exhaust and noise emissions as established by the National Parks Service. An engine exceeding these standards while operating on a blend of gasoline and bio-isobutanol has been developed based on a production four-stroke snowmobile engine. Miller cycle operation was achieved via late intake valve closing and turbocharging. The production Rotax ACE 600cc 2 cylinder engine was modeled using Ricardo WAVE. After this model was validated with physical testing, different valve lift profiles were evaluated for brake specific fuel consumption and brake power. The results from this analysis were used to determine a camshaft profile for Miller cycle operation. This was done to reduce part load pumping losses and increase engine efficiency while maintaining production power density. A catalytic converter was added to reduce exhaust gas emissions, as measured by the EPA 40 CFR
Blair, Jeffrey, Bower, Glenn
Regulated and Unregulated Emissions from a Flex Fuel Motorcycle Fuelled with Various Gasoline/Ethanol Blends2014-32-003211/11/2014
Motorcycle sales have increased consistently during the last decade mostly in developing countries, especially in the BRICS. Low cost and less fuel consumption comparing to cars associated to the economic growth are the main reason for such trend. Emission limits have become stricter and the use of gas after treatment devices is widely present in new models. Flex fuel motorcycles have now become available, but effects of the combination of diverse gasoline/ethanol blends on the emissions are still an open issue that requires further understanding. This paper presents the most recent results regarding regulated and unregulated emissions from a Flex Fuel motorcycle fuelled with 4 different gasoline/ethanol blends: E22, E61, E85 and 100% ethanol. Both regulated (CO, THC, NOx) and unregulated emissions (Aldehydes, NMHC, NH3, N2O) were studied. The main conclusion is that motorcycles equipped with three-way catalytic converters presented significant ammonia emissions in the tailpipe when
Daemme, Luiz Carlos, Penteado, Renato, Zotin, Fatima, Errera, Marcelo
Design of the Exhaust Manifold of a Turbo Charged Gasoline Engine Based on a Transient Thermal Mechanical Analysis Approach2014-01-288210/13/2014
The present paper describes a CAE analysis approach to evaluate the design of exhaust manifold of a turbo charged gasoline engine. It allows design engineers to identify structural weakness at the early stage or to find the root cause of exhaust manifold failures. A transient none-linear finite element method is used to calculate the plastic deformation and thermal mechanical behaviors of the exhaust manifold assembly during thermal shock cycles, which include rated speed full load, rated speed motored and idle speed conditions. A transient heat transfer simulation is performed to provide thermal boundary conditions for the nonlinear stress/strain analysis. The finite element model includes a part of cylinder head, exhaust manifold, gaskets, turbo charger housing, catalytic converter, brackets, bolts and nuts. The results show that plastic deformation is the main cause of manifold cracking and the manifold flange distortion causes the exhaust leakage. The simulation results indicate
Chen, Ming, Wang, Yanjun, Wu, Wenrui, Xin, Jun
The Effects of Diesel Oxidation Catalyst on Particulate Emission of Ethanol-Biodiesel Blend Fuel2014-01-273010/13/2014
Because of its cleanness and renewability, biodiesel has a great potential as the alternative of diesel fuel to confront with the increasing energy crisis and environment pollution. In this study, diesel oxidation catalyst (DOC) was used to reduce the typical regulated emission and particulate emission. The combined method of fuel design concept with diesel oxidation catalyst was applied in this study. DOC with Pt catalyst was equipped in the engine test bench in this study. The effects of DOC on diesel engine particulate emission fueled with Euro V diesel fuel, biodiesel and ethanol-biodiesel blends were investigated in this study. It was found that DOC seemed have no effects on NOx emission, while it could improve the oxidation reaction from NO to NO2. In the section of particulate emission, DOC could reduce the particulate mass and number concentration, especially in the range of smaller diameter particles. The SOF could be reduced effectively with DOC. With the increase of ethanol
Zhu, Lei, zhang, Wugao, Huang, Zhen, Fang, Junhua
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