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Viewing 1 to 30 of 21858
2017-03-28
Technical Paper
2017-01-0996
Sebastian Gramstat, André Cserhati, Matthias Schroeder
Since particle emissions from combustion engines have been reduced during the last decades, the importance of non-exhaust emission sources, such as airborne brake dust, tyre pollution, etc., is increasing. Unlike the powertrain, a conventional vehicle brake is an open system and the sampling of the emitted particles becomes a complex process. The presented study introduces a particular measurement setup for brake particle emission investigations. Beside a brake dynamometer, two solid particle counting systems (SPCS) were used to determine the emitted particle numbers. It must be mentioned that both devices were modified prototypes with a cut-off of 10 nm. During the studies an 18” two-piston frame-design brake caliper, in combination with low-steel brake linings and cast-iron brake discs, was used. As a first result it is shown that the employed setup and test procedure revealed a stabilised behaviour after a few test runs in terms of emitted particle numbers and friction conditions.
2017-03-28
Technical Paper
2017-01-0984
Wenran Geng, Diming Lou, Ning Xu
Recently Hybrid Electric Buses have been widely used in China. In order to study their emissions reduction effects, the exhaust emissions of an in-use diesel-electric hybrid bus have been evaluated both over China City Bus Cycles (CCBC) on chassis dynamometer and on the road using Portable Emissions Measurement Systems (PEMS). The diesel-electric hybrid bus adopts a coaxial parallel mode hybrid system and is driven by electric motor at 0~20km/h while engine keeps idling. Only if the vehicle speed exceeds 20km/h, engine and electric motor will provide driving force together, which leads to more violent transient conditions of engine. Firstly, exhaust emissions of the diesel-electric hybrid bus and a Chinese V stage bus with traditional powertrain have been tested on heavy chassis dynamometer over CCBC.
2017-03-28
Technical Paper
2017-01-0638
Neerav Abani, Nishit Nagar, Rodrigo Zermeno, Michael chiang, Isaac Thomas
Heavy-duty vehicles, currently the second largest source of fuel consumption and carbon emissions are projected to be fastest growing mode in transportation sector in future. There is a clear need to increase fuel efficiency and lower emissions for these engines. The Achates Power Opposed-Piston Engine has the potential to address this growing need. In this paper, results will be presented for a 9.8L three-cylinder OP Engine that shows the potential of achieving 51%+ brake thermal efficiency (BTE), while simultaneously satisfying 4.0 g/kWhr engine out NOx and 0.01 g/kWhr engine-out soot. The OP Engine architecture can meet this performance without the use of additional technologies such as thermal barrier coatings, waste heat recovery or additional turbo-compounding.
2017-03-28
Technical Paper
2017-01-0636
Vijai Shankar Bhavani Shankar, Nhut Lam, Arne Andersson, Bengt Johansson
The concept of double compression, and double expansion stages (DCEE) for improving the efficiency of piston reciprocating engines was introduced in SAE Paper 2015-01-1260. This engine configuration separates high, and low pressure units thereby effectively reducing friction losses. The presence of an additional expander stage also allows an extra degree of freedom to manipulate the combustion heat release rate so as to achieve better optimum between heat transfer, and friction losses. This paper presents a 1-D modeling study of the engine concept in GT-Power for assessing the sensitivity of engine losses to heat release rate at a given speed-load point. The simulations were constrained by limiting the range of maximum motoring pressures from 200 bar to 300 bar, and the maximum pressure during combustion to 300 bar. The maximum motor pressure was varied by constraining the compression ratio of the high pressure unit and adapting the low pressure unit accordingly.
2017-03-28
Technical Paper
2017-01-0644
Michael Pontoppidan, Adm José baeta
Vehicle emissions significantly increase the atmospheric air pollution and the green house gas (GHG) effect. This fact together with a fast global vehicle fleet growth requires a scientific technological solution, which introduces a significant reduction of vehicle fleet fuel consumption and emission to comply with future legislation. As a response to this requirement a prototype engine equipped with a torch ignition system and designed for stratified mixture conditions was made. The design is based on a commercial baseline engine layout. In this system, the combustion starts in a pre-chamber, where the pressure increase pushes the combustion jet flames through calibrated nozzles to be precisely targeted into the main combustion chamber. The combustion jet flames have high thermal and kinetic energy being able to promote a stable lean combustion process through enhanced mixture stratification.
2017-03-28
Technical Paper
2017-01-0907
Timothy Johnson, Ameya Joshi
This review paper summarizes major and representative developments in vehicular emissions regulations and technologies from 2016. The paper starts with the key regulatory advancements in the field, including newly proposed Euro 6 type regulations for Beijing, China, and India in the 2017-20 timeframe. Europe finalized real driving emissions (RDE) standards with the conformity factors for light-duty diesel NOx and GDI PN ramping down to 1.5X by 2021. The California heavy duty (HD) low-NOx regulation is advancing and may be proposed in 2017/18 for implementation in 2023+. LD (light duty) and HD engine technology continues showing marked improvements in engine efficiency. Key developments are summarized for gasoline and diesel engines to meet both the emerging criteria and greenhouse gas regulations. LD gasoline concepts are achieving 45% BTE (brake thermal efficiency or net amount of fuel energy gong to the crankshaft) and closing the gap with diesel.
2017-03-28
Technical Paper
2017-01-0584
Haksu Kim, Jaewook Shin, Myoungho Sunwoo
The demand for electric power consistently increases for internal combustion engine (ICE) vehicles, as the number of electric components grows in the vehicles. In effect, this causes an increase in fuel consumption when charging their batteries. Therefore, research on an energy management system that can limit such increases in fuel consumption is necessary. In conventional electric systems for vehicles, the alternator is controlled by a feedback system that uses battery State Of Charge (SOC). In order to reduce fuel consumption, the application of extra engine power is important. However, it is difficult to utilize extra engine power in the conventional system. In order to overcome such limitations in conventional systems, in this paper, we propose a predictive energy management strategy based on a rule-based alternator control mode switch. The strategy progresses in two stages.
2017-03-28
Technical Paper
2017-01-0588
Adithya P Reddy Ranga, Gopichandra Surnilla, Joseph Thomas, Ethan sanborn, Mark linenberg
Dual fuel injection systems, like PFI+DI (port fuel injection + direct injection system) are being increasingly used in gasoline engine applications to increase the engine performance, fuel efficiency and reduce emissions. At a given engine operating condition, the air/fuel error is a function of the fraction of fuel injected by each of the fuel systems. If the fraction of fuel from each of the fuel system is changed at a given operating condition, the fuel system error will change as well making it challenging to learn the fuel system errors. This paper aims at describing the adaptive fueling control algorithm to estimate the fuel error contribution from each individual fuel system. Considering the fuel injection system slope errors to be the significant cause for air-fuel errors, a model structure was developed to calculate the fuel system adaptive correction factor as a function of changing fraction of fueling between the fuel systems.
2017-03-28
Technical Paper
2017-01-0592
Robin Holmbom, Bohan Liang, Lars Eriksson
Turbocharging plays an important role in the downsizing of engines. Model based approaches for boost control is increasing the demand for controlling the wastegate flow more accurately. In todays’ cars the wastegate is usually controlled only with a duty cycle and with no position feedback. Because of this a constant duty cycle can give different wastegate positions depending on the engine operating point. Currently the most frequently used feedback in todays’ cars is the boost pressure which is the controller reference. This means that there is a large time constant from actuation command to the effect in boost pressure which can impair dynamic performance. In this paper the performance of an electrical controlled vacuum actuated wastegate also named as vacuum wastegate is compared to an electrical servo-controlled wastegate also named electric wastegate.
2017-03-28
Technical Paper
2017-01-0605
Anthony D'Amato, Yan Wang, Dimitar Filev, Enrique Remes
Government regulations for fuel economy and emission standards have driven the development of technologies that improve engine performance and efficiency. These technologies are enabled by an increased number of actuators and increasingly sophisticated control algorithms. As a consequence, engine control calibration time, which entails sweeping all actuators at each speed-load point to determine the actuator combination that meets constraints and delivers ideal performance, has increased significantly. In this work we present two adaptive optimization methods, both based on an indirect adaptive control framework, which improve calibration efficiency by searching for the optimal process inputs without visiting all input combinations explicitly. The difference between the methods is implementation of the algorithm in steady-state vs dynamic operating conditions.
2017-03-28
Technical Paper
2017-01-1288
Noriko Shisa, Shinsuke Ishihara, Yougui Huang, Mikio Asai, Katsuhiko Ariga
Despite methanol is toxic to human health and causes serious damage to automobile engine and components in fuel system, there are increasing distribution of methanol-containing gasoline in some area. Methanol demonstrates similar chemical properties to ethanol (which is established as an additive to gasoline), so that it is challenging to identify methanol-containing gasoline without performing proper chemical analysis (e.g., GC-MS). In this study, we aim to develop low-cost, portable, and easy-operation sensor that selectively changes its color (from red purple to blue purple) in response to methanol-containing gasoline. The colorimetric sensor will be useful for automobile users to avoid unexpected refueling of methanol-containing gasolines. Our methanol sensor is a thin film of clay mineral (layered double hydroxide, LDH) embedded with dye molecules (oxoporphyrinogen, OxP).
2017-03-28
Technical Paper
2017-01-0721
Michele Bardi, Olivier Colin, André Nicolle, Gilles Bruneaux
This paper is a contribution to the understanding of the formation and oxidation of soot in typical Diesel combustion. A common rail ECN spray A injector (single axial-oriented orifice) was tested in a optically accessible test-chamber at engine relevant conditions. High-speed OH* and high-speed 2D extinction imaging were performed simultaneously to link together the flame chemistry and the soot data information. The experiments were carried out for different fuels (EU Diesel, JetA1, n-dodecane) performing parametric variations of the boundary conditions. The proposed analysis methodology enabled the identification of the sooting behavior of each fuel by evaluating the relationship between two of the measured parameters, namely lift-off length and the soot maximum axial extinction value (Max KL). The relationship between these two parameters allowed to distinguish the behavior of the different fuels.
2017-03-28
Technical Paper
2017-01-0990
Carl Paulina, Dan McBryde, Mike Matthews
ABSTRACT Track Road Load Derivations (RLDs) and subsequent load matching on test cell dynamometers has traditionally been conducted using vehicle coastdowns (CDs). A vehicle’s speed changes during these coastdowns are used to calculate the drag forces that slow vehicles when on the road. Drag forces exerted on a vehicle, can also be quantified by holding a vehicle at a specific steady state speed and measuring the forces required to maintain that speed. Track coastdowns require the vehicle to be placed in neutral to accomplish. Hybrid Electric Vehicles (HEVs) do not necessarily have true neutral mechanical power transmission modes and some vehicles exhibit large variations from CD run to CD run. This paper focuses on two steady state speed methods to quantify parasitic forces which a vehicle must work against when motoring.
2017-03-28
Technical Paper
2017-01-0611
Alf Erik Viktor Leek, Kristoffer Ekberg, Lars Eriksson
Today’s need for fuel efficient vehicles, together with increasing engine component complexity, makes optimal control a valuable tool for the process of finding the most fuel efficient control strategies. To efficiently calculate the solution to optimal control problems a gradient based optimization technique is desirable. However, this requires that the model is continuously differentiable. Many existing control-oriented Diesel engine models do not have this property, often due to signal saturations or discrete conditions. This paper offers a continuously differentiable, mean value engine model, of a heavy-duty diesel engine equipped with VGT and EGR, suitable for optimal control purposes. The model is developed from an existing, validated, engine model, but adapted to be continuously differentiable and therefor tailored for usage in an optimal control environment.
2017-03-28
Technical Paper
2017-01-0963
Hoon Cho, Thomas Brewbaker, Devesh Upadhyay, Brien Fulton, Michiel Van Nieuwstadt
Many excellent papers have been written about the subject of estimating engine-out NOx on diesel engines based on real-time available data. The claimed accuracy of these models is typically around 6-10% on validation data sets with known inputs. This reported accuracy typically ignores the uncertainty around the inputs, thus arriving at an optimistic estimate of the model accuracy in a real-time application. In our paper we analyze the effect of uncertainty on the accuracy of engine-out NOx estimates via a numerical Monte Carlo simulation and show that this effect can be significant. Even though our model is based on an in-cylinder pressure sensor, this sensor is limited in its capability to reduce the effect of other measured inputs to the model. We give a brief presentation of the model and focus on the uncertainty analysis.
2017-03-28
Technical Paper
2017-01-0970
Johann C. Wurzenberger, Christoph Triebl, Susanne Kutschi, Christoph Poetsch
Wall flow filters have successfully been used for many years to abate particulate matter emissions. Since then, modeling of this type of filter device has supported the development by a broad variety of approaches reaching from explicit pressure drop correlations up to complex 3D CFD simulations. 1D models are commonly used in the context of plant modeling supporting control development and calibration. Here most differences can be identified by the applied filtration, active or passive soot regeneration and catalytic reaction mechanisms. The proposed paper discusses a 1D+1D wall flow filter model resolving transport phenomena along the axial direction of the inlet/outlet channel and also in transverse direction through the soot cake and filter wall. The basic set of gas phase flow equations is extended by the passive transport of an arbitrary number of soot classes. The balance equations of deposit soot are extended to handle individual soot population.
2017-03-28
Technical Paper
2017-01-0993
Sheng-Chieh cheng, Yong-Yuan Ku, Ko Wei Lin
Due to the deterioration of the Earth's environment, many governments around the world strengthen vehicles emission regulation more and more strictly. In order to measurement vehicles exhaust emissions on the real road situation. We establish a Simple Emission Measurement system (SEMS) to detect the amount of real time emission. The SEMS use stoichiometric theory to predict fuel consumed, accumulated CO2 and NOX mass by detect NOX volume concentration, O2 volume concentration and exhaust air flow rate. The Simple Emission Measurement system has been validated by engine test using ESC (European Stationary Cycle) and ETC (European Transient Cycle) test procedure, and the result shows the error of emission data is about ± 10% compare to the emission analyzer in the vehicle testing laboratory.
2017-03-28
Technical Paper
2017-01-0985
Joachim Demuynck, Cecile Favre, Dirk Bosteels, Heather Hamje, Jon Andersson
The market share of Gasoline Direct Injection (GDI) vehicles has been increasing, promoted by its positive contribution to the overall fleet fuel economy improvement. It has however been reported that this type of engine is emitting more ultrafine particles than the Euro 6c Particle Number (PN) limit of 6e11/km that will be introduced in Europe as of September 2017 in parallel with the Real Driving Emission (RDE) procedure. The emissions performance of a state-of-the-art GDI passenger car was measured, first in the original configuration without a Gasoline Particulate Filter (GPF) and then as a demonstrator with a coated GPF in the underfloor position. Regulated emissions were measured on the European regulatory test cycles NEDC and WLTC and in real-world conditions with Portable Emissions Measurement Systems (PEMS) according to the published European RDE procedure (Commission Regulation (EU) 2016/427 and 2016/646).
2017-03-28
Technical Paper
2017-01-0991
Sunil Pathak, Vineet sood, Yograj Singh, Salim Abbasbhai Channiwala
Presently, regulatory emission and fuel consumption values for new car are determined by a type-approval process. Several studies have shown that the type-approval data is not representative for real-world usage. The working group designated as Real Driving Emissions – Light Duty Vehicle (RDE-LDV) assessing the potential of two candidate testing procedures: Emission testing with random driving cycles in the laboratory, and on-road emissions testing with Portable Emissions Measuring Systems (PEMS) as real driving test procedure. The recent reports concluded that both PEMS and random cycle testing are technically feasible. The random cycle testing is more effective than emissions testing with the NEDC, but potentially cover a smaller range of driving conditions but it allows use of established, accurate analytical equipment, and enables the repetition and reproduction of individual emission tests under defined conditions.
2017-03-28
Technical Paper
2017-01-0992
Dereck Dasrath, Richard Frazee, Jeffrey Hwang, William Northrop
Partially premixed low temperature combustion (LTC) in diesel engines is a strategy for reducing soot and NOX formation though it is accompanied by higher unburned hydrocarbon (UHC) emissions compared to conventional mixing-controlled diesel combustion. In this work, two independent methods of quantifying light UHC species from a diesel engine operating in early LTC (ELTC) modes were compared: Fourier transform infrared (FT-IR) spectroscopy and gas chromatography-mass spectroscopy (GC-MS). A sampling system was designed to capture and transfer exhaust samples for off-line GC-MS analysis, while the FT-IR sampled and quantified engine exhaust in real time. Three different ELTC modes with varying levels of exhaust gas recirculation (EGR) were implemented on a modern light-duty diesel engine. GC-MS and FT-IR concentrations were within 10 % for C2H2, C2H4, C2H6, and C2H4O. While C3H8 was identified and quantified by the FT-IR, it was not detected by the GC-MS.
2017-03-28
Technical Paper
2017-01-0926
Kentaro Iwasaki
The diesel particulate filter (DPF) has been used in the automobile industry for around a decade. As a key technology for emissions control the DPF design needs to be increasingly optimized to expand its function to deal with any emission to meet not only PM/NOx regulation but also CO2 targets through minimizing any fuel penalty. Cost is extremely important to deliver an effective after-treatment catalyst. . Aluminum titanate and cordierite-based material DPFs are very cost effective in part because their properties allow monolith-manufacturing. Furthermore, geometrical design of the DPF channel structure can contribute to multi-functionalization of the DPF to provide further advantages. Practically, square and asymmetric square-designed channel structures in DPF have been utilized on current after-treatment systems. Asymmetric hexagonal-designed channel technology has recently been shown to provide lower backpressure and higher ash-capacity for longer DPF lifetime usage.
2017-03-28
Technical Paper
2017-01-0952
Michael B. Hopka, David Bilby, Michiel Van Nieuwstadt
The resistive particulate matter sensor (PMS) is rapidly becoming ubiquitous on diesel vehicles as a means to diagnose particulate filter (DPF) leaks. By design the device provides an integrated measure of the amount of PM to which it has been exposed during a defined measurement period within a drive cycle. The state of the art resistive PMS has a large deadband before any valid output related to the accumulated PM is realized. As a result, most DPF monitors that use the PMS consider its output only as an indicator that a threshold quantity of PM has amassed at the sensor rather than a real-time measure of concentration. This measurement paradigm has the unfortunate side effect that as the PM OBD threshold decreases, or the PMS is used on a vehicle with a larger exhaust volume flow, the duration of measurement required to reach the same PM sensor output increases.
2017-03-28
Technical Paper
2017-01-1274
Jason M. Luk, Hyung Chul Kim, Robert De Kleine, Timothy J. Wallington, Heather L. MacLean
This study investigates the life cycle greenhouse gas (GHG) emissions of a set of vehicles using two real-world gliders (vehicles without powertrains or batteries); a steel-intensive 2013 Ford Fusion glider and a multi material lightweight vehicle (MMLV) glider that utilizes significantly more aluminum and carbon fiber. These gliders are used to develop lightweight and conventional models of internal combustion engine vehicles (ICV), hybrid electric vehicles (HEV), and battery electric vehicles (BEV). Our results show that the MMLV glider can reduce life cycle GHG emissions despite its use of lightweight materials, which can be carbon intensive to produce, because the glider enables a decrease in fuel (production and use) cycle emissions. However, the fuel savings, and thus life cycle GHG emission reductions, differ substantially depending on powertrain type. Compared to ICVs, the high efficiency of HEVs decreases the potential fuel savings.
2017-03-28
Technical Paper
2017-01-0562
Xiuxiu Sun, Xingyu Liang, Hanzhengnan Yu, Yuesen Wang, Yajun Wang
The two-stroke marine engine have higher NOx emission for its low rotational speed. However, the limited can be improved for the NOx emission in recent years. The large size of the two-stroke marine engine makes the use of experimental techniques, the investigate this potential, expensive and time consuming. The computational fluid dynamic (CFD) model of two-stroke marine diesel engines can be built in this article. The model is valeted with the results of experiment. The in-cylinder pressure is agreement with that of experiment. The error located in the acceptable range for the emission products, NOx, CO, HC and CO2. This model can be used in the simulated the performance of two-stroke marine diesel engines using EGR. Four different EGR ratio can be simulated in this article, for example 10%, 20%, 30% and 40%. The in-cylinder pressure, temperature, specific fuel consumption, power and the quantity of emission product can be compared for different EGR ratio.
2017-03-28
Technical Paper
2017-01-0691
Louis-Marie Malbec, Julian kashdan
Previous experimental data obtained in constant volume combustion vessels have shown that soot-free diffusive flames can be achieved in a Diesel spray if the equivalence ratio at the flame lift-off location is below 2. The so-called Leaner Lifted-Flame Combustion (LLFC) strategy is a promising approach to limit the levels of in-cylinder soot produced in Diesel engines and potentially reduce the dependence on the Diesel particulate filter. However, implementing such strategies in light-duty engines is not straightforward due to the effects of charge confinement , non-steady boundary conditions and spray-spray interactions compared to the simplified configuration of a free-jet in a constant-volume combustion vessel. The present study aims at trying to gain a better understanding of the requirements in terms of injector and engine settings in order to reach the LLFC regime in a light-duty engine. Experiments were performed on a 0.5L single-cylinder optical engine.
2017-03-28
Technical Paper
2017-01-0679
Kelvin Xie, Shui Yu, Xiao Yu, Geraint Bryden, Ming Zheng, Mengzhu Liu
In order to meet the future carbon dioxide legislation, advanced clean combustion engines are tending to employ low temperature diluted combustion strategies along with intensified cylinder charge motion. The diluted mixtures are made by means of excess air admission or exhaust gas recirculation. A slower combustion speed during the early flame kernel development because of the suppressed mixture reactivity will reduce the reliability of the ignition process and the overall combustion stability. In an effort to address this issue, an ignition strategy using a multi-pole spark igniter is tested in this work. The igniter uses three electrically independent spark gaps to allow three spatially distributed spark discharge. The presence of the three independent poles offers the possibility for the poles to spark at the same time, sequentially, or to be reserved for instrumentation purposes.
2017-03-28
Technical Paper
2017-01-0910
Michiel Makkee, Yixiao Wang
Next Generation Automotive DeNOx Catalysts: Ceria what else? The NOx abatement of the more fuel economic lean-burn engines remains a demanding challenge. The Di-Air system opts to meet future stringent emission standards, especially under realistic driving conditions [1]. It is claimed that this system is able to maintain high NOx conversion to N2 at high temperatures and exhaust flow rates by applying direct high frequency high intensity fuel injections just upstream of a NSR catalyst in the exhaust with only a very small fuel penalty. How this system can achieve this performance remains largely unresolved. A detailed investigation is required in order to elucidate the role that the different potential catalyst components play. Among other our TAP study shows NO reduction to N2 over H2 and hydrocarbons reduced (La-Zr doped) ceria [2]. Ceria is found to be capable of fuel oxidation (above 500 oC) and NO reduction.
2017-03-28
Technical Paper
2017-01-0707
Srinivas Padala, Minh Khoi Le, Yoshihiro Wachi, Yuji Ikeda
The effect of microwave enhanced plasma (MW Plasma) on diesel spray combustion was investigated inside a constant volume high pressure chamber. A microwave-enhanced plasma system, in which plasma discharge generated by a spark plug was amplified using microwave pulses, was used to introduce plasma. Initially, the plasma was introduced to the diesel spray before the occurrence of auto-ignition, to understand the effect of additional oxidizer entertainment on ignition delay of diesel spay. High speed imaging of natural luminosity indicated an earlier appearance of flame in the with-plasma cases compared to the respective without-plasma conventional operation. These results corresponds well to the behavior of the heat-release rates, suggesting a reduction-effect by MW plasma on the ignition delay of diesel combustion. Later, the plasma was introduced downstream the flame lift-off and in the soot cloud to estimate the soot reduction effect by plasma.
2017-03-28
Technical Paper
2017-01-0741
Xinlei Liu, Laihui Tong, Hu Wang, Zunqing Zheng, Mingfa Yao
In this work the gasoline compression ignition (GCI) combustion characterized by the premixed gasoline port injection and gasoline direct injection in a single-cylinder diesel engine was investigated experimentally and computationally. In the experiment, the premixed ratio, injection strategy, and exhaust gas recirculation (EGR) rates were varied with the pressure rise rates below10 bar/crank angle. The experimental results showed that the higher premixed ratio and earlier injection timing with high injection pressure resulted in advanced combustion phasing and improved thermal efficiency, while the pressure rise rates and NOx emissions increased. The soot, HC, and CO emissions decreased with higher injection pressure and earlier injection timing, while the HC emission increased significantly with higher premixed ratio. With the increase of EGR, the soot and NOx emissions decreased while the CO and HC emissions increased significantly.
2017-03-28
Technical Paper
2017-01-0945
Markus Dietrich, Carsten Steiner, Gunter Hagen, Ralf Moos
State of the art for NOx reduction for low- and heavy-duty diesel engines is the ammonia SCR technique. Today’s SCR control approaches are model-based, relying on NOx sensors and the ammonia-providing urea dosing module. Based on model uncertainties, low ammonia storage levels on the catalyst surface are aimed to avoid ammonia slip. This leads to the disadvantage of catalyst oversizing or that the maximum catalytic potential is not exploited. The radio-frequency (RF) or microwave based catalyst state determination offers the ability to operate automotive catalysts at its optimal point. By using the catalyst canning as a resonator, knowledge about the electric properties of the catalyst can be derived from its resonance parameters. Their direct correlation to the catalyst state has already been proven for the oxidation state of a TWC, the soot loading on a DPF/GPF and the ammonia storage on vanadium and zeolite based SCR catalysts.
Viewing 1 to 30 of 21858