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Viewing 1 to 30 of 14986
2017-03-28
Technical Paper
2017-01-0915
Haomiao Zhang, Yuanzhou Xi, Changsheng Su, Z. Gerald Liu
Diesel exhaust fluid, DEF, (32.5 wt.% urea aqueous solution) is widely used as the NH3 source for selective catalytic reduction (SCR) of NOx in diesel aftertreatment systems. The transformation of sprayed liquid phase DEF droplets to gas phase NH3 is a complex physical and chemical process. Briefly, it experiences water vaporization, urea thermolysis/decomposition and hydrolysis. Depending on the DEF doser, decomposition reaction tube (DRT) design and operating conditions, incomplete decomposition of injected urea could lead to solid urea deposit formation in the diesel aftertreatment system. The formed deposits could lead to engine back pressure increase and DeNOx performance deterioration etc. The formed urea deposits could be further transformed to chemically more stable substances upon exposure to hot exhaust gas, therefore it is critical to understand this transformation process.
2017-03-28
Technical Paper
2017-01-0933
Yunhua Zhang, Diming Lou, Piqiang Tan, Zhiyuan Hu, Qian Feng
Biodiesel as a renewable energy is becoming increasingly attractive due to the growing scarcity of conventional fossil fuels. Meanwhile, the development of after-treatment technologies for the diesel engine brings new insight concerning emissions especially the particulate matter pollutants. In order to study the coupling effects of biodiesel blend and CCRT (Catalyzed Continuously Regeneration Trap) on the particulate matter emissions, the particulate matter emissions from an urban bus operated under steady and transient conditions respectively on real road equipped with and without CCRT (the same bus) fuelled with biodiesel blends BD10 (90% pure diesel and 10% biodiesel by volume) and BD0 (100% pure diesel) was tested and analyzed using electrical low pressure impactor (ELPI). Results showed that the particulate number-size distribution of BD10 had two peaks in nuclei mode and accumulation mode respectively except the condition of high speed, which was similar to BD0.
2017-03-28
Technical Paper
2017-01-1014
David Moyer, Roger Khami, Andrew Bellis, Thomas Luley
Engine Air Induction Systems Hydrocarbon Trap (HC Trap) Designs, to limit evaporative fuel emissions, have evolved over time. This paper discusses a range of HC Traps that have evolved in Engine Air Induction Systems. (AIS) The early Zeolite Flow through Hydrocarbon Trap utilized an exhaust catalyst technology internal stainless steel furnace brazed substrate coated with Zeolite media. This HC Trap was installed in the AIS Clean Air Tube. This design was heavy, complicated, and expensive but met the urgency of the implementation of the new evaporative emissions regulation. The latest Ford Motor Company HC Trap is a simple plastic tray containing activated carbon with breathable non-woven polyester cover. This design has been made common across multiple vehicle lines with planned production annual volume in the millions. The cost of the latest HC Trap Bypass design is approximately 5% of the original Stainless Steel Zeolite Flow Through HC Trap.
2017-03-28
Technical Paper
2017-01-0932
Nehemiah S I Alozie, George Fern, David Peirce, Lionel Ganippa
ABSTRACT The use of diesel particulate filter (DPF) has become a standard after treatment technology in modern diesel engine however; pressure drop develops across the filter as PM accumulates. This requires quick periodic burn-out without incurring thermal runaway temperatures that could compromise DPF integrity in operation. Adequate understanding of soot oxidation is central to design and manufacture of efficient filter traps suitable for the engine system. In this study, we have examined the oxidation of PM generated from a high speed direct injection (HSDI) diesel engine, ran with 20% and 40% blends of two biodiesel fuels. The PM samples were collected on a Pall Tissuquartz filter during constant engine load and oxidised non-isothermally in a thermogravimetric analyser (TGA). Then results obtained are compared with PM oxidation data obtained from pure petrodiesel.
2017-03-28
Technical Paper
2017-01-0949
Makoto Ito, Mitsuru Sakimoto, Zhenzhou Su, Go Hayashita, Keiichiro Aoki
New two-A/F systems different from usual A/F-O2 systems are being developed to cope with strict regulation of exhaust gas. In the two-A/F systems, two A/F sensors are equipped in front and rear of a three-way catalyst. The A/F-O2 systems are ideas which use a rear O2 to detect exhaust gas leaked from three-way catalyst early and feed back. On the other hand, the two-A/F systems are ideas which use a rear A/F sensor to detect nearly stoichiometric gas discharged from the three-way catalyst accurately, and to prevent leakage of exhaust gas from the three-way catalyst. Therefore, accurate detection of nearly stoichiometric gas by the rear A/F sensor is the most importrant for the two-A/F systems. In general, the A/F sensors can be classified into two types, so called, one-cell type and two-cell type. Because the one-cell type A/F sensors don’t have hysteresis, they have potential for higher accuracy.
2017-03-28
Technical Paper
2017-01-0913
Evangelos Georgiadis, Toru Kudo, Olaf Herrmann, Ken Uchiyama, Juergen Hagen
In order to comply with emission regulation, reach their profitability targets and minimise the in-use cost of their vehicles, OEMs are seeking solutions to optimise their aftertreatment systems. For SCR system engineers, one of the most important challenges is to reduce the system's cost, while keeping its high level of NOx emission reduction performance. Ways to achieve this cost reduction include 1. using an engine out NOx estimation model instead of a NOx sensor upstream of the SDPF catalyst and 2. eliminating the Ammonia Slip Catalyst downstream of the SDPF catalyst. Achieving these challenging targets requires actions on the complete SCR system, from the optimisation of mixing and uniformity in the SDPF catalyst to the development of robust controls. To face these challenges, DENSO has developed a novel exhaust reverse flow concept, combined with a blade mixer, increasing mixing length and total mixing performance.
2017-03-28
Technical Paper
2017-01-0929
Satoru Inoda, Yasutaka Nomura, Hirotaka Ori, Yuji Yabuzaki
PN regulation including Euro6 will be scheduled / tightened worldwide for gasoline engine especially GDI(Gasoline Direct Injection) engine. To meet PN regulation with GDI engine, particle filter which is also utilized for a diesel engine is needed. There are two types of particle filters for gasoline engine (Gasoline Particulate Filter ; GPF). One is bare GPF (additional type) , the other is coated GPF (replaced type). "Replaced" GPF (coated GPF) has advantages of cost / space / pressure drop compare to “Additional" GPF (bare GPF). There are three key performances for coated GPF. Firstly, three way performance is equivalent or more than three way catalyst. Secondly, a low pressure drop which is not to affect engine power and fuel consumption. Finally, a high PN filtration efficiency to meet the PN regulations. ZONE coating technology which is utilized for three way catalyst is also effective for GPF to improve three way performance.
2017-03-28
Technical Paper
2017-01-0986
Mohd Azman Abas, Shaiful Fadzil Zainal Abidin, Srithar Rajoo, Ricardo Martinez-Botas, Muhammad Izzal Ismail
Abstract Engine stop/start and cylinder deactivation are increasingly in use to improve fuel consumption of internal combustion engine in passenger cars. The stop/start technology switches off the engine to whenever the vehicle is at a stand-still, typically in a highly-congested area of an urban driving. The inherent issue with the implementation of stop/start technology in Southeast Asia, with tropical climate such as Malaysia, is the constant demand for the air-conditioning system. This inevitably reduces the duration of engine switch-off when the vehicle at stop and consequently nullifying the benefit of the stop/start system. On the other hand, cylinder deactivation technology improves the fuel consumption at certain conditions during low to medium vehicle speeds, when the engine is at part load operation only.
2017-03-28
Technical Paper
2017-01-0908
Fanxu Meng, Asanga Wijesinghe, John Colvin, Carolyn LaFleur, Richard Haut
Abstract Natural gas (NG), which consists of mostly methane, can be co-combusted with diesel fuel in existing compression ignition engines through dual fuel technology with reasonable engine modifications. The removal of short-chain alkanes (e.g. CH4, C2H6 and C3H8) of a dual fuel (natural gas and diesel) engine raises a distinctive topic to the exhaust aftertreatment system (ATS). However, there are few studies reported based on tests with real engine exhaust. This present study focuses on the conversion of short-chain alkanes by Co, Ni and Cu/ZSM-5 catalysts, which are commonly used for oxidation/partial oxidation and reforming. These catalysts are tested with exhaust of a dual-fuel (natural gas and diesel) engine. The complicated and dynamic exhaust composition, determined by the engine loading and natural gas substitution, can result in different components in the exhaust and various conversions for species.
2017-03-28
Technical Paper
2017-01-0912
Joel Op de Beeck, Scott Mccleary, Joshua Butler, Issam Djemili, Mihai Baja
Abstract Automotive SCR systems for diesel NOx reduction are dimensioned to reduce NOx efficiently in all driving conditions. In this regard the DEF storage and delivery system is developed to operate in a full range of temperatures, voltages, pressures, etc. To allow a control for optimal performance, sensors are added in the system (temperature, level, pressure sensor). Recently, a DEF quality sensor has been added to assure the correct concentration of urea in water in the onboard DEF tank. Now the question is raised how to assure that the DEF quality sensor is operating correctly and is giving an accurate indication of the liquid in the tank. The objective of this study is to define an independent method (PQD) to verify liquid quality, and challenge the signal generated by the DEF quality sensor. This study describes a possible method and the progress on its validation in various automotive driving conditions.
2017-03-28
Technical Paper
2017-01-0924
Jan Schoenhaber, Nikolas Kuehn, Bastian Bradler, Joerg Michael Richter, Sascha Bauer, Bernd Lenzen, Christian Beidl
Abstract Recently, the European Union has adopted a new regulation on Real-Driving-Emissions (RDE) and also China is considering RDE implementation into new China 6 legislation. The new RDE regulation is focused on measuring nitrogen oxides (NOx) and particulate number (PN) emissions of both light-duty gasoline and diesel vehicles under real world conditions. A supplemental RDE test procedure was developed for European type approval, which includes on-road testing with cars equipped with portable emission measurement systems (PEMS). This new regulation will significantly affect the engine calibrations and the exhaust gas aftertreatment. In this study the impact of the new RDE regulation on two recent EU 6b certified turbocharged direct injected gasoline vehicles has been investigated. A comparison of several chassis dyno drive cycles with two new defined on-road RDE cycles was performed.
2017-03-28
Technical Paper
2017-01-0928
Osama M. Ibrahim
Abstract Diesel oxidation catalysts with ultra-low NO2 emissions have been developed based on palladium-tungsten (Pd-W). The catalysts are supported by aluminum-yttrium oxides (Al2O3-Y2O3) nano-washcoat on sintered metal fibers. Elemental composition analysis was performed using Energy Dispersive Spectroscopy (EDS) to quantify the distribution of the Al2O3-Y2O3 nano-washcoats and Pd-W catalysts on the surface of the metal fibers. Initially, emissions measurements were conducted to evaluate the performance of Pd-W catalysts using small coated samples of sintered metal fibers. The results show that the catalysts selectively oxidize CO into CO2 and reduce NO2 into NO, resulting in over 90% reduction in CO emissions and up to 85% reduction in NO2 emissions. Scale-up of an Active Diesel Particulate Filter (ADPF) was then tested on a Cummins 5.9L ISB diesel engine using the US-FTP transient test cycle and the ISO 8178 8-mode test cycle.
2017-03-28
Technical Paper
2017-01-0957
Ian Smith, Thomas Briggs, Christopher Sharp, Cynthia Webb
Abstract It is projected that even when the entire on-road fleet of heavy-duty vehicles operating in California is compliant with 2010 emission standards of 0.20 g/bhp-hr, the National Ambient Air Quality Standards (NAAQS) requirements for ambient ozone will not be met. It is expected that further reductions in NOX emissions from the heavy-duty fleet will be required to achieve compliance with the ambient ozone requirement. To study the feasibility of further reductions, the California Air Resources Board (CARB) funded a research program to demonstrate the potential to reach 0.02 g/bhp-hr NOX emissions. This paper details the work executed to achieve this goal on the heavy-duty Federal Test Procedure (FTP) with a heavy-duty natural gas engine equipped with a three-way catalyst. A Cummins ISX-12G natural gas engine was modified and coupled with an advanced catalyst system.
2017-03-28
Technical Paper
2017-01-0988
Michael Cunningham, Mi-Young Kim, Venkata Lakkireddy, William Partridge
Abstract Measuring axial exhaust species concentration distributions within a wall-flow aftertreatment device provides unique and significant insights regarding the performance of complex devices like the SCR-on-filter. In this particular study, a less complex aftertreatment configuration which includes a DOC followed by two uncoated partial flow filters (PFF) was used to demonstrate the potential and challenges. The PFF design in this study was a particulate filter with alternating open and plugged channels. A SpaciMS [1] instrument was used to measure the axial NO2 profiles within adjacent open and plugged channels of each filter element during an extended passive regeneration event using a full-scale engine and catalyst system. By estimating the mass flow through the open and plugged channels, the axial soot load profile history could be assessed.
2017-03-28
Technical Paper
2017-01-0992
Dereck Dasrath, Richard Frazee, Jeffrey Hwang, William Northrop
Abstract 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 GCMS.
2017-03-28
Technical Paper
2017-01-0997
Roberto Aliandro Varella, Gonçalo Duarte, Patricia Baptista, Luis Sousa, Pablo Mendoza Villafuerte
Abstract The gap between regulated emissions from vehicle certification procedures and real-world driving has become increasingly wider, particularly for nitrogen oxides (NOx). Even though stricter emission regulations have been implemented, NOx emissions are dependent on specific, short-duration driving events which are difficult to control, therefore high concentrations of these pollutants are still being measured in European cities. Under certification procedures, vehicle emissions compliance is evaluated through standards, recurring to driving cycles performed on chassis dynamometer under controlled laboratory conditions. Different countries use different standard cycles, with the US basing their certification cycle on FTP-75 and Europe using NEDC (Euro 5/6c)/WLTP (Euro 6d).
2017-03-28
Technical Paper
2017-01-0447
Zhe Li, Mike Dong, Dennis Harrigan, Michael Gardner
In gasoline Powertrain systems, the evaporative emission control (EVAP) system canister purge valve (CPV) can be actuated by pulse-width modulated (PWM) signals. The CPV is an electronically actuated solenoid. The PWM controlled CPV, when actuated, creates pressure pulsations in the system. This pulsation is sent back to the rest of the EVAP system. Given the right conditions, the fill limit vent valve (FLVV) inside the fuel tank can be excited. The FLVV internal components can be excited and produce noise. This noise can be objectionable to the occupants. Additional components within the EVAP system may also be excited in a similar way. This paper presents a bench test method using parts from vehicle’s EVAP system and other key fuel system components.
2017-03-28
Technical Paper
2017-01-0914
Mengchao Zhang
Since diesel engines have higher thermal efficiency, larger power and better fuel economy than gasoline engines, diesel engines are widely used in vehicle, construction machinery and agricultural machinery. However, they emit more hazardous pollutants than gasoline engines, especially particulate emission, which has negative impact on human health and environment quality. In order to meet future increasingly stringent regulations for particulate emission, exhaust gas after-treatment technologies of diesel engines are essential. Particulate emissions from a heavy-duty diesel engine which meets the China national V emission regulation were studied, and the engine was equipped with/without diesel oxidation catalyst (DOC), catalyzed diesel particulate filter (CDPF) and selective catalytic reduction (SCR). The fuel used in this article is ultra low sulfur diesel fuel whose sulfur content is less than 10 ppm.
2017-03-28
Technical Paper
2017-01-0679
Kelvin Xie, Shui Yu, Xiao Yu, Geraint Bryden, Ming Zheng, Mengzhu Liu
Abstract 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 discharges. The multi-pole spark strategy displayed more advanced combustion phasing and lower phasing variability compared to single spark discharges.
2017-03-28
Technical Paper
2017-01-0683
Michael Fischer, Philipp Kreutziger, Yong Sun, Adam Kotrba
Abstract External Exhaust Gas Recirculation (EGR) has been used on diesel engines for decades and has also been used on gasoline engines in the past. It is recently reintroduced on gasoline engines to improve fuel economy at mid and high engine load conditions, where EGR can reduce throttling losses and fuel enrichment. Fuel enrichment causes fuel penalty and high soot particulates, as well as hydrocarbon (HC) emissions, all of which are limited by emissions regulations. Under stoichiometric conditions, gasoline engines can be operated at high EGR rates (> 20%), but more than diesel engines, its intake gas including external EGR needs extreme cooling (down to ~50°C) to gain the maximum fuel economy improvement. However, external EGR and its problems at low temperatures (fouling, corrosion & condensation) are well known.
2017-03-28
Technical Paper
2017-01-0684
Vickey B. Kalaskar, Raphael Gukelberger, Bradley Denton, Thomas Briggs
Abstract Dedicated EGR has shown promise for achieving high efficiency with low emissions [1]. For the present study, a 4-cylinder turbocharged GDI engine which was modified to a D-EGR configuration was used to investigate the impact of valve phasing and different injection strategies on the reformate production in the dedicated cylinder. Various levels of positive valve overlap were used in conjunction with different approaches for dedicated cylinder over fueling using PFI and DI fuel systems. Three speed-load combinations were studied, 2000 rpm 4 bar IMEPg, 2000 rpm 12 bar IMEPg, and 4000 rpm 12 bar IMEPg. The primary investigation was conducted to map out the dedicated cylinders' performance at the operating limits of intake and exhaust cam phasing. In this case, the limits were defined as conditions that yielded either no reformate benefit or led to instability in the dedicated cylinder.
2017-03-28
Technical Paper
2017-01-0700
Valentin Soloiu, Aliyah Knowles, Jose Moncada, Emerald Simons, Martin Muinos, Thomas Beyerl
Abstract The Cottonseed biodiesel combustion, sound and vibrations have been evaluated in a medium duty single cylinder DI engine (1.1L/cyl) by comparison with s ULSD#2 reference values. The engine was supercharged and had 20% EGR and all tests were conducted at 1400 rpm and at 4 bar BMEP load. Cylinder pressure was determined using a Kistler piezoelectric transducer. Combustion pressures peaked at 76 bar for both fuels. Ignition delay for CS100 decreased by 0.16 ms when compared to the ULSD#2 baseline. This would lead to a 23% lower peak heat release rate when operating CS100. The pressure rise rate for CS100 was 20% lower than ULSD#2, which related to the reduced ringing intensity for the biodiesel. The sound and vibrations were measured using a B&K condenser type multi-field microphone, and a tri-axial, piezoelectric accelerometer. All noise & vibration signals were analyzed with CPB and FFT Analysis, and Crank Angle Domain Analysis with B&K Pulse Platform software.
2017-03-28
Journal Article
2017-01-0581
Stephen C. Burke, Matthew Ratcliff, Robert McCormick, Robert Rhoads, Bret Windom
Abstract In some studies, a relationship has been observed between increasing ethanol content in gasoline and increased particulate matter (PM) emissions from vehicles equipped with spark ignition engines. The fundamental cause of the PM increase seen for moderate ethanol concentrations is not well understood. Ethanol features a greater heat of vaporization (HOV) than gasoline and also influences vaporization by altering the liquid and vapor composition throughout the distillation process. A droplet vaporization model was developed to explore ethanol’s effect on the evaporation of aromatic compounds known to be PM precursors. The evolving droplet composition is modeled as a distillation process, with non-ideal interactions between oxygenates and hydrocarbons accounted for using UNIFAC group contribution theory. Predicted composition and distillation curves were validated by experiments.
2017-03-28
Technical Paper
2017-01-0936
Pavel Krejza, Jaroslav Pekar, Jiri Figura, Lukas Lansky, Dirk von Wissel, Tianran Zhang
Diesel automotive engines after-treatment systems face greater challenges with every iteration of emission norm legislation. Major improvements in tailpipe NOx removal need to be achieved to fulfil the upcoming post EURO 6 norms and Real Driving Emissions (RDE) limits. Multi-brick systems employing combinations of multiple selective reduction catalysts (SCR) with an ammonia oxidizer (CUC) are proposed to cover operation over wide temperature range, however, control of multi-brick systems is complex due to many unmeasurable states. Usage of sophisticated model based predictive controls (MPC) makes the control task straight forward and less error prone compared to classic PID control. This paper shows the application of MPC to a SCR multi-brick system. Storage levels for SCR are calculated by optimization based on NOx conversion efficiency keeping tailpipe NH3 slip under emission limits.
2017-03-28
Technical Paper
2017-01-0943
Cory S. Hendrickson, Devesh Upadhyay, Michiel Van Nieuwstadt
Over the past decade urea-based selective catalytic reduction (SCR) has become a leading aftertreatment solution to meet increasingly stringent Nitrogen oxide (NOx) emissions requirements in diesel powertrains. A common trend seen in modern SCR systems is the use of "split-brick" configurations where two SCR catalysts are placed in thermally distinct regions of the aftertreatment. One catalyst is close-coupled to the engine for fast light-off and another catalyst is positioned under-floor to improve performance at high space velocities. Typically, a single injector is located upstream of the first catalyst to provide the reductant necessary for efficient NOx reduction. This paper explores the potential benefit, in terms of improved NOx reduction and control of NH3 slip, of having independently actuated injectors in front of each catalyst.
2017-03-28
Technical Paper
2017-01-0944
Ryuji Ando, Takashi Hihara, Yasuyuki Banno, Makoto Nagata, Tomoaki Ishitsuka, Nobuyuki Matsubayashi, Toshihisa Tomie
Cu-SSZ-13 is widely used as a material for Cu-SCR catalyst. The Cu-SCR catalyst shows high NOx performance and has high thermal durability but it deteriorates in NOx performance when it suffers Sulfur poisoning. Authors investigated the detailed mechanism how the catalyst is poisoned by Sulfur, and also studied the optimum de-Sulfation conditions. As to the Sulfur adsorption site in the Cu-zeolite, we performed DFT calculation to know the site candidate and we performed precise characterization. As characterization techniques of Sulfur poisoning of the catalyst, we mainly used EUPS (Extreme Ultraviolet Photoelectron Spectroscopy) and DRIFTS. By those techniques, we found out that Sulfur adsorbs on ion-exchanged Cu site and Al site in the Zeolite structure. Especially the Cu site is an active site of the catalyst and thus the Cu-SCR catalyst deteriorated by the Sulfur poisoning.
2017-03-28
Technical Paper
2017-01-0606
Ashley Wiese, Anna Stefanopoulou, Julia Buckland, Amey Y. Karnik
Low-Pressure Exhaust Gas Recirculation (LP-EGR) has been shown to be an effective means of improving fuel economy and suppressing knock in downsized, boosted, spark ignition engines. LP-EGR is particularly beneficial at low-speed, high-load conditions, but can lead to combustion instability at lower loads. The transport delays inherent in LP-EGR systems slow the reduction of intake manifold EGR concentrations during tip-out events, which may lead to excessive EGR concentrations at low load. This paper explores leveraging Variable Valve Timing (VVT) as a means of improving the rate of reduction of intake manifold EGR concentration prior to tip-out. At higher boost levels, high valve overlap may result in intake manifold gas passing directly to the exhaust manifold. This short-circuiting behaviour could potentially improve EGR evacuation rates.
2017-03-28
Technical Paper
2017-01-0922
Akito Takayama, Takahiro Kurokawa, Hiroki Nakayama, Takuya Katoh, Makoto Nagata
New Pd-Rh type CC-TWC (three way catalysts in CC (close-coupled) position) has been developed to improve low-temperature gas activity. In this study Pd top and Rh bottom layered TWC was used, and Ba and La were tested as an additive to Pd, respectively. Alumina was used for Pd support and La or Ba was co-supported to Pd. The catalysts were aged at 950C for 200hrs and CO, HC and NOx performance were evaluated. As a result, Pd-La catalyst showed higher gas performance than Pd-Ba catalyst. The reason and mechanism of this phenomenon were investigated by three points. First one is Pd activation by the additives, second one is Pd particle size by increasing thermal durability of alumina support, and third one is specific NOx adsorption and desorption by the additives. Pd activity seemed to be increased by La addition but details of activation energy analysis and characterization of Pd by XPS, etc. are under investigation.
2017-03-28
Technical Paper
2017-01-0921
Bharadwaj Sathiamoorthy, Alex Graper, Andrew McIntosh, William Kaminski
The automotive aftermarket industry is an extremely cost competitive market to say the least. Aftermarket manufacturers are sought by customers primarily for their ability to replace an OES for a fraction of the cost. This pressurizes the manufacturers to yield on performance abilities to get a share in the market place. The TWC system in gasoline vehicles not only acts as an emissions reduction device but is an integral part of the overal vehicle performance itself, especially since the introduction of OBD II systems in 1995. An inefficient catalyst not only leads to excessive tailpipe emissions but also acts detrimental to vehicle fueling and hence overall performance. The aftemarket catalyst industry which is regulated by EPA and CARB for gasoline engines is subject to meeting a mandatory performance standard for the same reason. There are several advancement in catalyst technologies to gain performance but this may or may not apply to the aftermarket manufacturers.
2017-03-28
Technical Paper
2017-01-0917
Go Hayashita, Motoki Ohtani, Keiichiro Aoki, Shuntaro Okazaki
Trying to prevent global warming and air pollution, Toyota has led the world in the field of after treatment technologies including the three-way catalyst (TWC) system with oxygen sensor. In this study, a new emission control system for Toyota New Global Architecture (TNGA) Engine which brings lower fuel consumption and higher performance for creating ever-better cars is reported. The new system was adopted the exhaust cooling system and small capacity TWC. These can achieve a balance between heating TWC for early activation and cooling TWC for protection. As a result, regardless of the platform or the unit type of the vehicle, it is possible to unify the catalyst temperature which is a key parameter in the exhaust gas purification. In order to reduce emission also with the small capacity TWC, it is necessary to a high accuracy air-fuel ratio (A/F) control.
Viewing 1 to 30 of 14986