Display:

Results

Viewing 31 to 60 of 23141
2016-04-05
Technical Paper
2016-01-0194
Yici Li, Wei Tian
There are several exhaust after-treatment processes for the flameproof diesel engine, one of which is smog dilution equipment of air jet that was employed several years ago, whereas the application confine of the equipment is shrank gradually because of the purification effect. Based on the smog dilution equipment of air jet at present, a novel equipment called a dry cooling equipment is presented whose structure is redesigned, analyzed and optimized. The intrinsic relationship is proposed through the interpretation of key factors including throat dimension, baffle and extend plate of guide.
2016-04-05
Technical Paper
2016-01-0996
Thomas L. Darlington, Dennis Kahlbaum, Shon Van Hulzen, Robert L. Furey
In 2006-2008, EPA and DOE tested fifteen Tier 2 vehicles on 27 fuels. The fuels were match-blended, meaning that as ethanol levels changed, other blendstocks were added to try to maintain prescribed distillation temperatures. EPA's analysis of the EPAct data showed that higher aromatics and to a lesser extent, higher levels of ethanol increase PM emissions. In their analysis of fuel effects, EPA found that RVP, T50, T90, and ethanol affected emissions. However, EPA did not evaluate the effects of other distillation temperatures, like T70. The fuel blender added blendstocks with boiling points in the T50-T80 range to ethanol fuels to hit certain T50 and T90 targets. It is likely that the addition of these higher boiling blendsotcks increased PM emissions and the omission of a distillation parameter between T50 and T90 (like T70) as a explanatory variable for PM modeling increased the predicted response of PM to ethanol.
2016-04-05
Technical Paper
2016-01-0927
David Culbertson, Magdi Khair, James Pradun, Henning Gero Petry, Anne Ungermann
Modifications have been made to the calibration and control of Diesel engines to increase the temperature of the exhaust especially in cold weather and part load operation. The main purpose for this advanced calibration is to enable the reduction of emissions by improving catalytic activity. An alternative method for increasing exhaust temperature is providing electric heat. Test results show the feasibility of applying various amounts of electric heat and the related increases in exhaust temperature as well as speed of heating. Simulation modeling extends the application of electric heat to a complete engine map and explores the potential for fuel economy and NOX conversion benefits compared to engine based heating methods.
2016-04-05
Technical Paper
2016-01-0947
Junhui Li, Neal Currier, Aleksey Yezerets, Hai-Ying Chen, Howard Hess, Shadab Mulla
Typical Lean NOx Trap (LNT) catalyst composition includes precious metal components (Pt, Pd, and/or Rh), responsible for NO oxidation during lean operation and NOx reduction during rich operation. It was found that oxidation state of Rh plays a key role in catalyzing NO reduction to N2 under net reducing conditions. This sensitivity of catalytic activity results in changes in efficiency of the LNT catalyst. Kinetic analysis of the NO reduction was performed in an attempt to elucidate the underlying mechanistic relationship, where it was found that NO reduction over reduced Rh can be well described by an Arrhenius equation with first-order dependence on NO concentration. The activation energy of the NO reduction process over reduced Rh was found to be ~18014kJ/mol, and independent of the reductant used or the degree of hydrothermal aging. These findings are consistent with NO dissociation being the rate-limiting step in the NO reduction process.
2016-04-05
Technical Paper
2016-01-0992
Justin Koczak, Andre Boehman, Matthew Brusstar
With increasingly stringent light duty particulate emissions regulations, it is of great interest to better understand the events leading to particulate matter formation. Building a thorough understanding of particulate matter formation is an essential step in developing effective control strategies. It is especially important to do this in such a way as to emulate real driving behaviors, including cold starts and transients. In this study, it was desired to realistically examine the evolution of the particulate emissions during transient operation in a recent model year vehicle equipped with a GDI engine. Three of the major federal test cycles were selected as evaluation schemes: the FTP, the HWFET, and the US06. These cycles capture much of the driving behaviors likely to be observed in typical driving scenarios. Measurements included particle size distributions from a TSI EEPS fast-response particle spectrometer, as well as real-time soot emissions from an AVL MSS soot sensor.
2016-04-05
Technical Paper
2016-01-1287
Kazutaka Kimura, Yuki Kudo, Akinori Sato
In recent years, in order to reduce greenhouse gasses (GHG) emission, automobile manufacturers are developing various eco-friendly cars, such as HV, PHV, REV, EV, and FCV. But there are few commercial solar vehicles in the market. One of the reasons why automobile manufacturers did not focus their attention on this area is because the benefits of installing solar modules on vehicles at the real conditions were unclear. There are two difficulties to measure the benefits of installing solar modules on vehicles: (1) Vehicles travel under various insolation conditions (2) Insolation conditions differ in each region. To address the problem, we used the combinational analysis on the basis of the internet survey of 5,000 people and the public metrological data of 48 observation points in Japan. This survey gave us the information on car conditions such as place to park, whether the car is in the sunshine or in the shade, the operating region, and the trip distance.
2016-04-05
Technical Paper
2016-01-0945
Guanyu Zheng
Selective Catalytic Reduction (SCR) based on urea water solution (UWS) has become a promising technology to reduce Nitrogen Oxides (NOx) emission. However, urea might undergo incomplete evaporations resulting in formation of solid deposit on the inner surfaces of system including walls, mixers, limiting the production of NH3 and conversion of NOx that would decrease the performance of SCR system. Numerous design parameters of SCR system affect the formation of urea deposits, such as type of injector, injector mounting angle, geometrical configurations of mixer. The road experiment results indicate that very little deposits were formed at the mixer locations. According to the analysis, the reason might be that mixer put an influential effect on the UWS distribution uniformity and the residence time, thus causing the deposit formation on the wall surface.
2016-04-05
Technical Paper
2016-01-0971
Stefano Sabatini, Irfan Kil, Travis Hamilton, Jeff Wuttke, Luis Del Rio, Michael Smith, Zoran Filipi, Mark A. Hoffman, Simona Onori
Three Way Catalyst (TWC), is an effective pollutant conversion system widely used in current production vehicles to satisfy the strict emissions regulations. Unfortunately, TWC’s conversion efficiency decreases over time because of mechanical, chemical and/or thermal mechanisms, which cause the catalyst to age. The catalyst aging manifests in terms of decreased oxygen storage capacity(OSC). This paper presents a study of the aging impact on dynamic oxygen storage behaviors of TWC with respect to miles driven. A physics based oxygen storage model is used to incorporate the effect of aging on a specific model parameter. Identification and comparison of this parameter for a fresh and four differently aged TWCs in terms of miles driven, and validation results will be presented. It will be shown that the dynamic oxygen storage behaviors of TWC are significantly affected by aging, in that OSC significantly decreases as the aging (i.e. miles driven) increases.
2016-04-05
Technical Paper
2016-01-0915
Meeting future emission regulations for diesel vehicles will require usage of both diesel particulate filter technology and a NOx reduction catalyst. Due to its potential for fuel optimization and high efficiency in NOx removal, SCR is often the preferred technology for NOx reduction. Today the DPF and SCR catalysts are placed sequentially in the exhaust system. However, such sequential system configurations have several drawbacks: 1) large volume; 2) insufficient temperature for the SCR catalyst during cold start when the DPF is placed in front of the SCR; and 3) unfavourable conditions for passive soot regeneration (lower NO2 and temperature) if the SCR is placed upstream of the DPF. The problems can potentially be solved by integrating the SCR catalyst into the particulate filter as one multi¬functional unit.
2016-04-05
Technical Paper
2016-01-0958
Kenichiroh KOSHIKA, Nobuya IWAMI, Takayuki ICHIKAWA, Hisakazu Suzuki, Toshiro Yamamoto, Yuichi Goto, Masakazu IWAMOTO
Degradation of deNOx performance was found in in-use heavy-duty vehicles with a urea SCR system in Japan. Causes of the degradation were studied and two major reasons were suggested here; HC poisoning and deactivation of pre-oxidation catalysts. Hydrocarbons accumulated on the catalysts inhibited the catalysis. Although they were easily removed by a simple heat treatment, but the treatment could recover partly the original catalytic performance for deNOx reaction. The unrecovered catalytic activity was found to result from decrease in conversion of NO to NO2 on pre-oxidation catalysts. The pre-oxidation catalysts were thus studied in detail by various techniques to reveal the causes of the degradation: Exhaust emission tests for in-use vehicles, effect of the heat treatment on the SCR systems, measurements of surface areas and pore volumes, and structural and chemical changes in active components during the deactivation were systematically investigated.
2016-04-05
Technical Paper
2016-01-0979
Jonathan David Stewart, Rose Mary Stalker, Richard O'Shaughnessy, Roy Douglas, Andrew Woods
The introduction of new automotive after treatment systems relies heavily on expensive and time consuming engine and vehicle based testing to ensure that the emissions meet legislative requirements throughout the specified life. The catalyst degradation behaviour is critical to ensuring emission targets are met over time. Given the criticality, it would be prudent to slightly over specify catalyst loadings to ensure these targets are achieved. The majority of catalyst development work is typically done either experimentally on cores at the micro-chemical level or comparatively using bespoke rapid ageing cycles on engines. The data from these tests is generally applied to a catalyst model for better understanding and optimisation of the catalyst bricks. As a result of years of testing (and successfully delivering) different powertrains and after treatment systems to the same test cycle, the OEMs have excellent comparative analysis databases.
2016-04-05
Technical Paper
2016-01-1008
Piotr Bielaczyc, Joseph Woodburn, Andrzej Szczotka
Sustained concern over anthropogenic greenhouse gas (GHG) emissions and general air quality has made the issue of exhaust emissions passenger cars a topic interest at an international level. This situation has lead to the re-evaluation of testing procedures in order to produce more ‘representative’ results. Laboratory test procedures for testing exhaust emissions are built around a speed trace – the ‘driving cycle’. Cycles may be developed in one context but later used in another: for example, the New European Driving Cycle was not developed to measure fuel consumption, but has ended up being used to that end. A new, global harmonized test procedure has introduced a new driving cycle (WLTC), with the focus firmly on measuring carbon dioxide emissions and fuel consumption. However, it appears likely that sooner or later this cycle will also be used for measuring regulated exhaust gas pollutants.
2016-04-05
Technical Paper
2016-01-0825
William Fedor, Joseph Kazour, James Haller, Kenneth Dauer, Daniel Kabasin
LEV-3 regulation changes will require a 100% SULEV30 fleet average by 2025. While previous applications meeting SULEV30 have been primarily small 4- cylinder engines, the LEV-3 standards will require larger displacement engines to also meet SULEV30. One concept investigated to reduce the cold start engine-out HC emission is to heat the injected fuel during the cold start and initial engine idle period. Improved atomization and increased vaporization of heated fuel will decrease wall wetting and unburnt fuel. This will result in more fuel available to take part in combustion, thus reducing the required injected fuel mass and HC emissions. Heated fuel was used to produce a representative fuel stream temperature profile which was developed with an early prototype Heated DI injector. Heated vs. unheated gasoline cold start emission performance was evaluated on a 3.8L 6-cylinder NA vehicle and a reduction in HC emissions using heated fuel was demonstrated.
2016-04-05
Technical Paper
2016-01-0989
Scott Eakle, Svitlana Kroll, Alice Yau, John Gomez, Cary Henry
Ideally, complete thermal decomposition of urea should produce only two products in active Selective Catalytic Reduction (SCR) systems: ammonia and carbon dioxide. In reality, urea thermal decomposition reaction is a two-step process that includes the formation of ammonia and isocyanic acid as intermediate products. Being highly reactive, isocyanic acid can initiate the formation of larger molecular weight compounds such as cyanuric acid, biuret, melamine, ammeline, ammelide, and dicyandimide. These compounds can be responsible for the formation of deposits on the walls of the decomposition reactor in urea SCR systems. Composition of these deposits varies with temperature exposure, and under certain conditions can create oligomers such as melam, melem, and melon that are difficult to remove from exhaust pipes. Deposits can affect efficiency of the urea decomposition, and if large enough, can inhibit the exhaust flow.
2016-04-05
Technical Paper
2016-01-0998
Shuli Wang, Xinda Zhu, L.M.T. Somers, L.P.H. de Goey
In this work, the influences of aromatics on combustion and emission characteristics from a heavy-duty diesel engine under various loads and exhaust gas recirculation (EGR) conditions are investigated. Tests were performed on a modified single-cylinder, constant-speed and direct-injection diesel engine. An engine exhaust particle sizer (EEPS) was used in the experiments to measure the size distribution of engine-exhaust particle emissions in the range from 5.6 to 560 nm. Two ternary blends of n-heptane, iso-octane with either toluene or benzaldehyde denoted as TRF and CRF, were tested, diesel was also tested as a reference. Test results showed that TRF has the longest ignition delay, thus providing the largest premixed fraction which is beneficial to reduce soot. However, as the load increases, higher in-cylinder pressure and temperature make all tested fuels burn easily, leading to shorter ignition delays and more diffusion combustion.
2016-04-05
Technical Paper
2016-01-0951
Jordan Elizabeth Easter, Stanislav V. Bohac
Advanced engine combustion strategies, such as HCCI and SACI, allow gasoline engines to achieve high levels of thermal efficiency with low levels of engine-out NOx emissions due to lean operation, optimal combustion duration and low combustion temperatures. However, even with low engine-out NOx, a modest NOx reduction is necessary to meet current and future emissions regulations. Typically this is handled with a TWC; however, lean operation prevents the TWC catalyst from functioning properly. One potential solution suggested in the research community for handling this challenge without the addition of costly NOx traps or on-board systems for urea injection is the passive TWC-SCR concept. This concept includes the integration of an SCR catalyst downstream of a TWC and the use of periods of rich operation to generate NH3 over the TWC to be stored on the SCR catalyst for use in NOx reduction during lean operation.
2016-04-05
Technical Paper
2016-01-0999
Yuesen Wang, Xingyu Liang, Ge-Qun Shu, lihui dong, Hanzhengnan Yu, Yajun Wang, Zhijun Li
In this paper, the influence of sulfur and ash fraction in lubricating oil on particle emissions was investigated via experimental works. Especially, we focus on the characterizations like size distribution, morphology and elements fraction in diesel particles. All of the research was done on a two-cylinder diesel engine under different load conditions. Five kinds of lubricating oils with different levels of sulfur and ash fraction were used in this study, among which a kind of 5W-30 (Castrol ACEA, C1) oil was used as baseline. Diesel particles were collected by thermophoretic system and filter, and analyzed by transmission electron microscopy and energy dispersive X-ray spectrum technique, respectively. Conclusions drawn from the experiments suggest that the sulfur and ash change the particle emissions directly. Both the sulfur and ash fraction in oil increase the amount of particles with large diameter and shift the size distribution to large size area.
2016-04-05
Technical Paper
2016-01-0960
Arifumi Matsumoto, Kenji Furui, Makoto Ogiso, Toru Kidokoro
Urea selective catalytic reduction (SCR) system is a prospect technology to reduce NOx emission from the diesel engine. Besides, on board diagnosis (OBD) system is required to be equipped with such device to suppress emission from malfunctioning system. The conventional OBD methodology of SCR catalyst is conducted by measuring NOx concentration downstream of the catalyst. Though, considering future OBD regulations, the erroneous diagnosis would be occurred due to the variability in actual environment. Then, we studied new methodology to utilize NH3 slip as a new diagnosis parameter in addition to NOx to enhance OBD accuracy. NH3 slip is increased in response to the degradation of NOx reduction performance because both phenomena are based on the deterioration of the capability to absorb NH3 of SCR catalyst. Furthermore, NH3 can be measured by existing NOx sensor because NH3 is oxidized to NOx internally. To make use of NH3 slip, the estimation model of NH3 slip was developed.
2016-04-05
Technical Paper
2016-01-0983
Travis C. Malouf, John J. Moskwa
Researchers in the Powertrain Control Research Laboratory (PCRL) at the University of Wisconsin-Madison have designed and built a single-cylinder engine transient test system that is capable of replicating the transient details of a multi-cylinder engine operation throughout the engine cycle. With this advanced tool, not only can many critical engine development tests be moved forward in the design timeline to the single-cylinder engine, shortening the development timeline, but new tests that are not possible on current single-cylinder engines can be performed on this new system. A few examples of these new tests are engine cold-start tests, engine restart tests, FTP or other homologation tests, etc. Representative multi-cylinder engine-out emissions are also possible with this new system. This paper is organized into three main parts.
2016-04-05
Technical Paper
2016-01-0972
Jiri Figura, Dejan Kihas, Jaroslav Pekar, Michael Uchanski, Nassim Khaled, Sriram Srinivasan
The amount of ammonia stored on the walls of the catalyst (or ammonia storage) is a parameter with significant impact on NOx reduction efficiency and undesired ammonia slip of Selective Catalytic Reduction catalysts. This makes the ammonia storage interesting for utilization in urea injection control. However, ammonia storage is not directly measurable onboard vehicles, it can only be estimated. Model-based online estimation requires models that are capable of capturing the main phenomena of the SCR and at the same time can be computed onboard vehicle. While the modeling of SCR and model-based control is well present in the literature, it is apparent that few attempts of implementing the models on production ECUs were published. This paper reviews literature on ammonia storage, outlet NH3 and NOx concentration estimation in SCR and SCR/DPF systems–including the estimation of NOx sensor cross-sensitive to NH3–in order to present the state of the art.
2016-04-05
Technical Paper
2016-01-0747
Vicente Bermudez, Raul Payri, J. Javier Lopez, Daniel Campos, Gilles Coma, Frederic Justet
Nowadays, 2-stroke CAI engines are under investigation in the context of direct injection gasoline engines as a solution to the CO2 future legislations. Since the main part of these investigations are centered on engine performance or some engine processes simulation, leaving aside particle number (PN) emission evaluation, this paper will focus on this last topic: particle emission analysis when using two different injectors, and a global comparison of PN emission of the present engine with its corresponding 4-stroke engine at three operating conditions keeping the same BMEP. This work has been performed in a single-cylinder gasoline engine with 0.3 l displacement, equipped with an air-assisted direct-injection fuel injection system. The equipment used in this study is a TSI-EEPS 3090 device for particle measurement and a DEKATI-FPS 4000 as a dilution system. Concerning the two injectors evaluated, significant differences in particle emission have been found.
2016-04-05
Technical Paper
2016-01-0575
Konstantinos Siokos, Rohit Koli, Robert Prucka, Jason Schwanke, Shyam Jade
Low pressure (LP) and cooled EGR systems are capable of increasing fuel efficiency of turbocharged gasoline engines, however they introduce control challenges. Accurate exhaust pressure modeling is of particular importance for real-time feedforward control of these EGR systems since they operate under low pressure differentials. To provide a solution that does not depend on physical sensors in the exhaust and also does not require extensive calibration, a coupled temperature and pressure physics-based model is proposed. The exhaust manifold is split into two different lumped sections based on flow conditions in order to calculate the turbine-outlet pressure, which is the driving force for LP-EGR. The temperature model uses the turbine-outlet temperature as an input, which is known through existing engine control models, to determine heat transfer losses through the exhaust.
2016-04-05
Technical Paper
2016-01-0678
Haifeng Lu, Jun Deng, Zongjie Hu, Zhijun Wu, Liguang Li, Fangen Yuan, Degang Xie, Shuang Yuan, Yuan Shen
China’s State Council has released the Energy-Saving and New Energy Vehicle Industrialization Plan, which states an expected fleet average target of 5.0L/100km by 2020. This means that the OEMs must apply much more advanced technologies to their production models. Compared to the EGR technology in diesel engines, the gasoline engine EGR is not a large-scale application in the market. But it has a promising potential to optimize the fuel economy for its anti-knock effect, pumping loss reduction and compatibility to the three-way catalyst. In this research, a 1.3L turbocharged PFI gasoline engine was used to evaluate the LP(low pressure) water-cooled EGR technology. The operating conditions vary from 1500rpm to 3000rpm and BMEP from 2bar to 17bar, and the common engine operating points in NEDC cycle are tested separately. Meanwhile, the compression ratio is changed from 9.5 to 10.5 to get higher fuel efficiency.
2016-04-05
Technical Paper
2016-01-1269
Naveen Kumar, Harveer Singh Pali
The present study was carried to explore the potential suitability of biodiesel as an extender of Kerosene in an off road dual fuel (gasoline start, kerosene run) generator set and results were compared with kerosene base line data. The biodiesel was blended with kerosene in two different proportions; 2.5% and 5% by volume. The blends were found to be stable and no phase separation was observed even after three months. Physico-chemical properties of blends were also found to be comparable with kerosene. Engine tests were performed on three test fuels namely K100 (Kerosene 100%), KB 2.5 (Kerosene 97.5% + Biodiesel 2.5%) and KB5 (Kerosene 95% + Biodiesel 5%). The engine was run on the same fuel volume and not on the same amount of energy during the trials. It was found that brake thermal efficiency [BTE] increases while brake specific energy consumption [BSEC] decreases with increasing biodiesel concentration in kerosene.
2016-04-05
Technical Paper
2016-01-0954
Jason Jacques, Thomas Pauly, Michael Zammit, Homayoun Ahari, Michael Smith
Significant reduction in Nitrogen Oxide (NOx) emissions will be required to meet LEV III Emissions Standards for Light Duty Diesel passenger vehicles (LDD). As such, Original Equipment Manufacturers (OEMs) are exploring all possible aftertreatment options to find the best balance between performance, robustness and cost. The primary technology adopted by OEMs in North America to achieve low NOx levels is Selective Catalytic Reduction (SCR) catalyst. The critical parameters needed for SCR to work properly are: an appropriate reductant such as ammonia (NH3) provided as urea, optimum operating temperatures, and optimum Nitrogen Dioxide (NO2) to NOx ratios (NO2/NOx). The NO2/NOx ratio is mostly influenced by Precious Group Metals (PGM) containing catalysts upstream of the SCR catalyst. Different versions of zeolite based SCR technologies are available on the market today and these vary in their active metal type (iron, copper, vanadia), and/or zeolite type.
2016-04-05
Technical Paper
2016-01-1005
Yuanzhou Xi, Nathan Ottinger, Z. Gerald Liu
Regulations on methane emissions from lean-burn natural gas (NG) and lean-burn dual fuel (natural gas and diesel) engines are becoming more stringent due to methane's strong greenhouse effect. Palladium-based oxidation catalysts are typically used for methane reduction due to their relative high reactivity under lean conditions. However, the catalytic activity of these catalysts is inhibited by the water vapor in the exhaust and decreases over time from exposure to trace amounts of sulfur. The reduction of deactivated catalysts in a net rich environment is known to be able to regenerate the catalyst. In this work, a multi-cycle of methane light-off & extinction test protocol was first developed to probe the catalyst reactivity and stability under simulated exhaust conditions. Then, the effect of two different regeneration gas compositions, denoted as regen-A and regen-B, was evaluated on a degreened catalyst and a catalyst previously tested on a natural gas engine.
2016-04-05
Technical Paper
2016-01-0088
Tervin Tan, Jin Seo Park, Patrick Leteinturier
The constant motivation for lower fuel consumption and emission levels has always been in the minds of most auto makers. With legislation playing a huge part in order to protect the environment. For instances, based on ICCT reports, EU passenger cars, weighing 1500kg, for today (2015) would need to meet the CO2 emission of 130g/km. This target is reduced to 95g/km in 2020. For the Chinese market, according to their CAFC target for passenger cars of 2015, has to meet the 6.9L/100km fuel consumption which translates to 163gCO2/km. At 2020, this target has been further reduced to 5L/100 which translate to 120gCO2/km. Though this is less than that of EU’s, the trend of fuel consumption and emission reduction is obvious and legislation needs to be met. Gasoline Port fuel injection has been a matured system for many years and cars sold in emerging markets still favor such system due to its less system complexity and cost.
2016-04-05
Technical Paper
2016-01-0787
Valentin Soloiu, Martin Muinos, Spencer Harp, Tyler Naes, Remi Gaubert
In this study, Premixed Charge Compression Ignition (PCCI) was investigated with alternative fuels, S8 and n-butanol. The S8 fuel is a Fischer Tropsch (FT) synthetic paraffinic kerosene (SPK) produced from natural gas. PCCI was achieved with a dual-fuel combustion incorporating 65% (by mass) port fuel injection (PFI) of n-butanol and 35% (by mass) direct injection (DI) of S8 with 35% exhaust gas recirculation. The experiments were conducted at 1500 rpm and varied loads of 1-5 bar brake mean effective pressure (BMEP). The PCCI tests were compared to an ultra-low sulfur diesel no. 2 (ULSD#2) baseline in order to determine how the alternative fuels effects combustion, emissions, and efficiencies. At 3 and 5 bar BMEP, the heat release in the PCCI mode exhibited two regions of high temperature heat release, one occurring near top dead center (TDC) and corresponds to the ignition of S8 (CN 62), and a second stage occurring ATDC from n-butanol combustion (CN 28).
2016-04-05
Technical Paper
2016-01-1002
Benjamin Kaal, Michael Grill, Michael Bargende
The increasing importance of transient emissions has so far been neglected, both in study and simulation. To address these points, transient emissions of a diesel engine were measured to develop a new model for the prediction of transient nitrogen oxide emissions. The fast emissions measurement instrumentation used delivered results with a temporal resolution on the order of a few degrees crank angle. Based on research of existing models the model proposed by Kožuch was chosen as the foundation for the new model due to its solid phenomenological structure and good predictive capability. Analyses of transient and static measurements revealed a direct influence of the cylinder wall temperature upon the nitrogen oxide emissions. To include this effect in the model, the burnt zone, where the nitrogen oxide formation occurs, was divided into two pseudo zones, the boundary and the core zone.
2016-04-05
Technical Paper
2016-01-0984
Venkatraman Mahadevan, Suresh Iyer, David Klinikowski
This paper investigates the effect of time alignment in the calculation of emissions from the raw exhaust stream of heavy-duty vehicles when tested on a chassis dynamometer. The effect of time alignment is significant in this case, as time-variant raw exhaust flow rate and emissions concentrations data are acquired continuously during a test (at 10 Hz), and their product is integrated during calculations. The response of the analyzer is delayed due to the time taken for transportation of the sample gases from the probe tip to the analyzer, and ‘flattened’ due to diffusion during this transport. This ‘convolution’ of the concentration data stream introduces an error in the final result, calculated in grams/mile. The convolution of the concentration data is corrected by the following method: the analyzer response (output) to a step change in the concentration of the species at the probe tip (input) is recorded to determine the ‘convolution function’.
Viewing 31 to 60 of 23141

Filter