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Technical Paper
2014-04-01
Daisuke Takaki, Hirofumi Tsuchida, Tetsuya Kobara, Mitsuhiro Akagi, Takeshi Tsuyuki, Morihiro Nagamine
Abstract This paper presents a study of a cooled exhaust gas recirculation (EGR) system applied to a turbocharged gasoline engine for improving fuel economy. The use of a higher compression ratio and further engine downsizing have been examined in recent years as ways of improving the fuel efficiency of turbocharged gasoline engines. It is particularly important to improve fuel economy under high load conditions, especially in the turbocharged region. The key points for improving fuel economy in this region are to suppress knocking, reduce the exhaust temperature and increase the specific heat ratio. There are several varieties of cooled EGR systems such as low-pressure loop EGR (LP-EGR), high-pressure loop EGR (HP-EGR) and other systems. The LP-EGR system was chosen for the following reasons. It is possible to supply sufficient EGR under a comparatively highly turbocharged condition at low engine speed. It is important for knocking suppression to remove nitrogen oxides (NOx) from the EGR gas, which means using EGR gas from the catalyst downstream.
Technical Paper
2014-04-01
Bernhard Kern, Stephanie Spiess, Joerg Michael Richter
Abstract With the growing awareness about the presence of fine/ultra fine particulates in the ambient air and their negative impact on climate and health, some regions of the world have started to look closer at the contribution of road traffic. Since Gasoline engines, in particular when injecting fuel directly into the combustion chamber, proved to emit relevant numbers of particulates, even hardly visible, the growing share of Gasoline DI engines and their small size of particulate emissions is a concern. To address the same, the EU has already set limits for the particulate number with EU6 from 2015 onwards. The US considers setting challenging limits by particulate mass. Since mass of ultra fine particulates is very low and difficult to measure, experts investigate if a measurement by number might better address the particular concern. The implementation of a coated Particulate Filter enables meeting not only basic demands during traditional emission test cycles. Also the particulate emissions during highly transient and high load driving conditions are reduced effectively.
Technical Paper
2014-04-01
Kazuki Nakamura, Athanasios Konstandopoulos, Margaritis Kostoglou, Toshiaki Shibata, Yuki Hashizume
Abstract Diesel particulate filters (DPFs) equipped with diesel vehicles have become indispensable components to capture the soot emitted from the engines from a viewpoint of both human health and global warming problems as well as the prevailing regulations. Meanwhile, the pressure drop caused by them leads to a direct increase of fuel consumption. In order to reduce it guaranteeing the sufficient soot filtration efficiency, we have developed the new concept of asymmetric plugging layout for the DPF design, so-called Valuable Plugging Layout (VPL), on the basis of octosquare (OS) structure and have clarified the advantage of the pressure drop reduction both experimentally and theoretically. The VPL-DPF consists of two kinds of octagonal/square inlet channels and octagonal outlet channels, and there are thought to be five filtration velocity modes as well as four kinds of soot deposit layers on each side of the inlet channel walls. No deterioration of the soot filtration performance and the reduction of the transient pressure drop of the VPL-DPF during the soot loading have been confirmed through the engine bench tests compared to those of the OS-DPF.
Technical Paper
2014-04-01
Keld Johansen, Henrik Bentzer, Arkady Kustov, Kenneth Larsen, Ton V.W. Janssens, Rasmus G. Barfod
Abstract Today, the DPF and SCR catalysts are combined sequentially in diesel exhaust systems. However, such sequential system configuration has several drawbacks: 1) large volume; 2) insufficient temperature for the SCR catalyst during cold start when DPF is placed in front of SCR; and 3) unfavorable conditions for passive soot regeneration if SCR is placed upstream of the DPF. The problems can potentially be solved by integrating the SCR catalyst into the particulate filter as one multifunctional unit. The study indicates that SCRonDPF based on Cu-zeolite type as SCR material can achieve the NOx conversion levels close to flow-through SCR catalysts for LDV (Light Duty Vehicles) using forced regenerations. Forced soot regeneration solves potential sulfur poisoning. For HDV (Heavy Duty Vehicles) applications with full managed passive soot regenerations, integration of V-based SCR formulations on DPF represents an attractive solution due to high sulfur resistance accompanied by low-temperature fuel economy.
Technical Paper
2014-04-01
Kihong Kim, Rahul Mital, Takehiro Higuchi, Seomoon Chan, Chang Hwan Kim
Abstract Diesel particulate filter (DPF) is a widely used emission control device on diesel vehicles. The DPF captures the particulate matter coming from the engine exhaust and periodically burns the collected soot via the regeneration process. There are various trigger mechanisms for this regeneration, such as distance, time, fuel and simulation. Another method widely used in the industry is the pressure drop across the filter. During calibration, relation between the pressure sensor reading and soot mass in the filter is established. This methodology is highly effective in successful DPF operation as pressure sensor is a live signal that can account for any changes in engine performance over time or any unforeseen hardware failures. On the other hand, any erroneous feedback from the sensor can lead to inaccurate soot mass prediction causing unnecessary regenerations or even needless DPF plugging concerns. A similar phenomenon was observed on certain vehicles where the DPF pressure reading jumped inexplicably leading to DPF plugging concerns.
Technical Paper
2014-04-01
Homayoun Ahari, Michael Zammit, Luis Cattani, Jason Jacques, Thomas Pauly
Abstract To meet TierII/LEVII emissions standards, light duty diesel (LDD) vehicles require high conversion efficiencies from the Aftertreatment Systems (ATS) for the removal of both Hydrocarbon (HC) and Nitrogen Oxide (NOx) species. The most populous configuration for LDD ATS have the Selective Catalytic Reduction (SCR) catalyst positioned on the vehicle behind the close coupled Diesel Oxidation Catalyst (DOC) and Catalyzed Diesel Particulate Filter (CDPF). This SCR position may require active heating measures which rely on the DOC/CDPF to provide heat through the combustion of HC and CO in the exhaust. Although DOCs are always impacted by their aging conditions, some aging conditions are shown to be both reversible and irreversible. Under continuous, high speed and high mileage conditions such as experienced in a modified Standard Road Cycle (SRC) or as it is better known, the High Speed Cycle (HSC), it is shown that the DOC's activity can deteriorate initially but significantly recover over repeated FTP-75 test cycles on fully aged catalysts.
Technical Paper
2014-04-01
Joel Op de Beeck, Kevin Slusser, Neall Booth
Abstract Automotive SCR systems are dimensioned to reduce NOx efficiently in normal driving conditions. In markets such as North America and Europe, extreme winter conditions are common over a period of many weeks where temperatures are usually below DEF (Diesel Exhaust Fluid) freezing temperatures at −11°C (12°F). In previous studies and applications, DEF was heated in the tank in a dedicated pot or alternatively by a standardized central heater. Due to the local character of these heating solutions, it was not possible to thaw the full tank volume. The objective of this study is to demonstrate how to significantly improve performance of the SCR system in cold weather conditions for passenger car, light commercial vehicles and SUV applications. The performance improvement is demonstrated by sustainability testing showing how much of the full tank content can be thawed and made available for injection in the exhaust system. Based on maximum average dosing rates of 250 g/h, external temperatures down to −40°C and depending on the tank shape the heater is designed to optimize tank heating performance.
Technical Paper
2014-04-01
Joel Michelin, Frederic Guilbaud, Alain Guil, Ian Newbigging, Emmanuel Jean, Martina Reichert, Mario Balenovic, Zafar Shaikh
Abstract Future Diesel emission standards for passenger cars, light and medium duty vehicles, require the combination of a more efficient NOx reduction performance along with the opportunity to reduce the complexity and the package requirements to facilitate it. With the increasing availability of aqueous urea, DEF or AdBlue® at service stations, and improved package opportunities, the urea SCR technical solution has been demonstrated to be very efficient for NOx reduction; however the complexity in injecting and distributing the reductant remains a challenge to the industry. The traditional exhaust system contains Diesel Oxidation Catalysts (DOC), Diesel Particulate Filters (DPF) and Selective Catalytic Reduction (SCR), all require additional heat to facilitate each of their specific functions. With some particular package scenarios the SCR catalyst maybe found after the particulate filter where elaborate light-off strategies need to be deployed to ensure activation under many different driving regimes.
Technical Paper
2014-04-01
Matthieu Lecompte, Stephane Raux, Arnaud Frobert
Abstract The selective catalytic reduction (SCR) based on urea water solution (UWS) is an effective way to reduce nitrogen oxides (NOx) emitted by engines. The high potential offered by this solution makes it a promising way to meet the future stringent exhaust gas standards (Euro6 and Tier2 Bin5). UWS is injected into the exhaust upstream of an SCR catalyst. The catalyst works efficiently and durably if the spray is completely vaporized and thoroughly mixed with the exhaust gases before entering. Ensuring complete vaporization and optimum mixture distribution in the exhaust line is challenging, especially for compact exhaust lines. Numerous parameters affect the degree of mixing: urea injection pressure and spray angle, internal flow field (fluid dynamics), injector location …. In order to quantify the mixture quality (vaporization, homogeneity) upstream of the SCR catalyst, it is proposed to employ non intrusive optical diagnostics techniques such as laser induced fluorescence (LIF).
Technical Paper
2014-04-01
Yi Liu, Wei Chen, Matthew Henrichsen, Arvind Harinath
Abstract Diesel emission aftertreatment system is usually designed to meet stringent packaging constraints, rendering a difficult situation to achieve perfect flow distribution inside the catalytic unit. The non-uniform flow pattern leads to a mal-distribution of flow velocity, temperature, and gas species in catalyst unit. Some catalysts are exposed to harsh working environment, while the rest catalysts are underutilized. This lowers the efficiency of overall catalyst unit and thus requires an oversized system to meet emission requirements. The flow mal-distribution also accelerates the uneven catalyst degradation, lowering the system durability. Hence, a quantitative description of packaging impact on catalyst performance is critical to assess the system efficiency and durability. In the present work, a mapping method is developed to combine catalyst performance with computational fluid dynamics (CFD) simulation. This method is used to analyze the performance and robustness of a SCR aftertreatment system using a series of packaging designs.
Technical Paper
2014-04-01
Xiangyu Feng, Yunshan Ge, Jianwei Tan, Jiaqiang Li, Yao Zhang, Chenglei Yu
Abstract The NOx conversion efficiency of vanadium-based SCR catalyst is lower under low temperature. Utilizing an exhaust analyzer, the effects of electrically heated catalyst on the performance of vanadium-based SCR catalyst under low temperature was studied on the engine test bench. The inlet temperature of SCR catalyst without the electrically heated catalyst were in the range of 150°C∼270°C under various steady engine modes, and the NSR (Normalized Stoichiometric Ratio) was set as 0.4,0.6,0.8,1.0. The results showed that under the space velocity of 20000h−1, with the application of the electrically heated catalyst, the inlet temperature of SCR increased about 19.9°C on average and the NOx conversion efficiency improved about 8.0%. The NOx conversion efficiency increased 1.7%∼8.6% at the temperatures of 150°C∼174°C, and 1.0%∼15.9% at the temperatures of 186°C∼270°C. The experiment space velocity properties indicated that with the electrically heated catalyst, the inlet temperature increase and the increasing rate of the NOx conversion efficiency both decreased with the increasing space velocity.
Technical Paper
2014-04-01
Xiaobo Song, Jeffrey Naber, John H. Johnson
Abstract Selective catalytic reduction (SCR) systems are in use on heavy duty diesel engines for NOx control. An SCR NOx reduction efficiency of higher than 95% is required to meet the proposed increasingly stringent NOx emission standards and the 2014-2018 fuel consumption regulations. The complex engine exhaust conditions including the nonuniformity of temperature, flow, and maldistribution of NH3 present at the catalyst inlet need to be considered for improved performance of the SCR system. These factors cause the SCR to underperform negatively impacting the NOx reduction efficiency as well as the NH3 slip. In this study, the effects of the nonuniformity of temperature, flow velocity and maldistribution of NH3 on the SCR performance were investigated using 1-dimensional (1D) model simulations for a Cu-zeolite SCR. The model was previously calibrated and validated to reactor and steady-state and transient engine experimental data. The SCR engine experimental measurements collected from a transient cycle were used as the baseline for the simulations.
Technical Paper
2014-04-01
Mengting Yu, Vemuri Balakotaiah, Dan Luss
Abstract The particulate matter (PM) emitted by a diesel engine is collected and then combusted in a diesel particulate filter (DPF). A sudden decrease of the engine load of DPF undergoing regeneration, referred to as a drop to idle (DTI), may create a transient temperature peak much higher than under stationary feed conditions. This transient temperature rise may cause local melting or cracking of the filter. We report here the dependence of the maximum temperature following a DTI on the DPF properties and its dependence on the operating conditions. The simulated impact of changes in DPF properties on peak regeneration temperature following a DTI is qualitatively similar to their impact under stationary operation. (1) The maximum DTI temperature and temperature gradient can be decreased by preheating the DPF before igniting the PM. (2) A decrease of the inlet gas temperature and/or a two-step regeneration can decrease the maximum DTI regeneration temperature. (3) The peak DTI regeneration temperature decreases upon an increase of either the filter wall thickness or the solid volumetric heat capacity. (4) When the DPF heat transfer is under axial heat Peclet number (Eqn. (4)) control, the peak temperature decreases upon an increase of the solid conductivity and/or a decrease of the filter aspect ratio (L/D). (5) The peak DTI temperature is a nonlinear function of the cell density. (6) The dependence of the maximum temperature gradient on the maximum regeneration temperature is not always monotonic.
Technical Paper
2014-04-01
Nic van Vuuren
Abstract The implementation of stringent nitrogen oxides (NOx) emissions reduction legislation in Europe and North America is driving the introduction of new exhaust aftertreatment systems, including those that treat NOx under the high-oxygen conditions typical of lean-burn engines. One increasingly common solution, referred to as Selective Catalytic Reduction (SCR), comprises a catalyst that facilitates the reactions of ammonia (NH3) with the exhaust nitrogen oxides (NOx) to produce nitrogen (N2) and water (H2O). It is customary with these systems to use a liquid aqueous urea solution, typically at a 32% concentration of urea (CO(NH2)2). The solution is referred to as AUS-32, and is also known under its commercial name of AdBlue® in Europe, and DEF - Diesel Exhaust Fluid - in the USA. The urea solution is injected into the exhaust and transformed to NH3 by various mechanisms for the SCR reactions. Urea injection systems using AUS-32 are now in production and becoming a widespread mature technology on many on-road automotive and off-road vehicle applications.
Technical Paper
2014-04-01
Wanyu Sun, Shufen Wang, Shanheng Yan, Lei Guo, Yuanjing Hou
Abstract Selective catalytic reduction (SCR) has become one of the primary technologies to reduce internal combustion engine (ICE) emission. The installation angle of urea injector plays an important role during the SCR process. The urea injector is often vertically mounted to the exhaust pipe for on road heavy duty truck because of its good performance and general packaging convenience, and this type of installation has been the focus of previous research. However, due to certain packaging constraints or responsiveness considerations, the injector is installed with an inclined acute angle to the exhaust pipe under some circumstance. To evaluate the underlying benefits and risks of this type of installation angle, a computational fluid dynamic (CFD) model based on the Renolds averaged Navier-Stokes (RANS) solver from AVL Fire is used to simulate the injection process of urea for an acute-angled 3-hole injector, through which, the urea spray's formation and motion, wallfilm accumulation and NH3 distribution uniformity characteristics are studied.
Technical Paper
2014-04-01
Stephan Stadlbauer, Harald Waschl, Luigi del Re
Abstract The emissions of modern Diesel engines, which are known to have various health effects, are beside the drivers torque demands and low fuel consumptions one of the most challenging issues for combustion and after treatment control. To comply with legal requirements, emission control for heavy duty engines is not feasible without additional hardware, usually consisting of a Diesel oxidation catalyst (DOC), a Diesel particulate filter (DPF) and a selective catalytic reduction (SCR) system. In contrast to other NOx reduction systems, e.g. lean NOx traps, the SCR system requires an additional ingredient, namely ammonia (NH3), to reduce the NOx emissions to non harmful components. Consequently, the correct amount of NH3 dosing in the SCR catalyst is one of the critical components to reach high conversion rates and avoid ammonia slip. Against this background and in contrast to existing proposals in which the NH3 dosing is often calculated based on a NOx emission sensor, this work presents a strategy to adopt the set point estimation of the NH3 dosing, based on a virtual NOx sensor extended by a virtual DOC model.
Technical Paper
2014-04-01
Yoshinori Otsuki, Kenji Takeda, Kazuhiko Haruta, Nobuhisa Mori
Abstract The particle number (PN) emission regulation has been implemented since 2011 in Europe. PN measurement procedure defined in ECE regulation No. 83 requires detecting only solid particles by eliminating volatile particles, the concentrations of which are highly influenced by dilution conditions, using a volatile particle remover (VPR). To measure PN concentration after the VPR, a particle number counter (PNC) which has detection threshold at a particle size of 23 nm is used, because most solid particles generated by automotive engines are considered to be larger than 23 nm. On the other hand, several studies have reported the existence of solid and volatile particles smaller than 23 nm in engine exhaust. This paper describes investigation into a measurement method for ultrafine PNCs with thresholds of below 23 nm and evaluation of the VPR performance for the particles in this size range. The detection efficiency of an ultrafine PNC was verified by following the ECE regulation procedure.
Technical Paper
2014-04-01
Chitralkumar V. Naik, Long Liang, Karthik Puduppakkam, Ellen Meeks
Abstract 3-D Computational Fluid Dynamics (CFD) simulations have been performed using a detailed reaction mechanism to capture the combustion and emissions behavior of an IFP Energies nouvelles optical gasoline direct injection engine. Simulation results for in-cylinder soot volume fraction have been compared to experimental data provided by Pires da Cruz et al. [1] The engine was operated at low-load and tests were performed with parametric variations of the operating conditions including fuel injection timing, inlet temperature, and addition of fuel in the intake port. Full cycle simulations were performed including intake and exhaust ports, valve and piston motion. A Cartesian mesh was generated using automatic mesh generation in the FORTÉ CFD software. For the simulations, a 7-component surrogate blend was used to represent the chemical and physical properties of the European gasoline used in the engine tests. A validated detailed combustion mechanism containing 230 species and 1740 reactions was employed to model the chemistry of the fuel surrogate combustion and emissions.
Technical Paper
2014-04-01
Hideki Goto, Kazuyoshi Komata, Shigekazu Minami
Abstract Among the platinum group metals (PGMs), rhodium (Rh) is known as an exceedingly valuable element for automotive catalysts due to its powerful catalytic function. Because Rh is a costly material, it is paramount to enhance its catalytic function in three-way catalysts (TWCs). This work reports results on the palladium (Pd)-Rh combination which assists the catalytic function of Rh. XPS and XRD are used to observe the Rh characteristics, and engine dynamometer and vehicle testing are conducted to measure catalytic performance and quantify the emission benefits of the Pd-Rh interaction in TWCs. It is well known that Pd-Rh forms a core-shell structured alloy with Rh in its core. This alloy exerts a large negative impact on NOx performance. However, it is inferred from our analyses that highly-dispersed Pd and Rh particles within a certain Pd/Rh atomic ratio prevent this deterioration phenomenon. In this work XPS analysis shows adding Pd increases the Rh0 concentration on the Rh surface when Pd is allocated in proximity to Rh, and the concentration of Rh0 created through the Pd-Rh interaction reaches a maximum at a certain Pd/Rh atomic ratio.
Technical Paper
2014-04-01
Erica King, David Wallace, E. Robert Becker
Abstract Platinum Group Metal (PGM) use is dominated by the automotive industry. The PGM market is sensitive to shifts in the drivers for emission control and the delicate supply-demand balance. Technology shifts in the emission control industry are particularly impactful because of the automotive market's dominance and the consequent ability to significantly affect metal prices. On the supply side, evolving ore ratios of platinum, palladium and rhodium, production ramp-up times, geopolitical factors, and labor relations contribute to a challenging production environment. This is mitigated by a growing above-ground supply from spent autocatalysts. The availability of spent autocatalyst is critical to alleviate the pressure on primary supply and is especially important in light of the hurdles primary PGM producers face. This paper reviews technology developments, legislative drivers, and consumer trends in the automotive industry and their impact on PGM demand. Evolving emission regulations for criteria pollutants around the world put pressure on catalyst performance and durability while greenhouse gas standards bring new challenges to the operating environment of these catalysts.
Technical Paper
2014-04-01
Cheng Tan, Hongming Xu, He Ma, Akbar Ghafourian
Abstract Transient operation is frequently used by vehicle engines and the exhaust emissions from the engine are mostly higher than those under the steady station. An experimental study has been conducted to investigate the effect of various valve timings and spark timings on combustion characteristics and particle emissions from a modern 3.0-liter Gasoline Direct Injection (GDI) passenger car engine. The transient condition was simulated by load increase from 5% to 15% at a constant engine speed with different settings of valve timings and spark timings. The transient particle emission measurement was carried out by a Cambustion DMS500 particulate analyser. The combustion characteristics of the engine during transient operation including cycle-by-cycle combustion variations were analyzed. The time-resolved particle number, particulate mass and particle size distribution were compared and analyzed between different engine settings. The existing transient lambda control cannot maintain stoichiometric combustion in the transition.
Technical Paper
2014-04-01
Joseph Kazour, Bizhan Befrui, Harry Husted, Michael Raney, Daniel Varble
Abstract Innovative nozzle hole shapes for inwardly opening multi-hole gasoline direct injectors offer opportunities for improved mixture formation and particulate emissions reduction. Compared to increased fuel pressure, an alternative associated with higher system costs and increased pumping work, nozzle hole shaping simply requires changes to the injector nozzle shape and may have the potential to meet Euro 6 particulate regulations at today's 200 bar operating pressure. Using advanced laser drilling technology, injectors with non-round nozzle holes were built and tested on a single-cylinder engine with a centrally-mounted injector location. Particulate emissions were measured and coking deposits were imaged over time at several operating fuel pressures. This paper presents spray analysis and engine test results showing the potential benefits of alternative non-round nozzle holes in reducing particulate emissions and enhancing robustness to coking with various operating fuel pressures.
Technical Paper
2014-04-01
Takahiro Umeno, Masaya Hanzawa, Yoshiyuki Hayashi, Masao Hori
Abstract In this study several NOx storage materials have been investigated to see their NOx storage properties. And sulfur release properties of these materials have been also investigated. Based on these findings, new LNT catalyst was developed. In this new LNT catalyst Barium is supported on one basic material, and Strontium is coated in the whole catalyst with high dispersion. And it shows higher NOx storage performance against conventional LNT one even though 10g/L of sulfur was introduced to the catalysts. According to analysis results of new LNT catalyst after sulfur poisoning, it was found that sulfur was mainly adsorbed on Strontium selectively, and then it formed sulfate compound as SrSO4. On the other hand, another sulfate compounds could be hardly observed. And regarding Barium on basic material some analysis measurement said that it has not only better NOx storage function, but also better sulfur release function. The assumption why new LNT catalyst has high sulfur resistance is that Strontium works like scavenger effect against sulfur, therefore it enables to keep higher NOx storage performance by Barium even if it contains much sulfur amount in the catalyst.
Technical Paper
2014-04-01
John Hoard, Nandagopalan Venkataramanan, Barbara Marshik, William Murphy
Abstract Ammonia, often present in exhaust gas samples, is a polar molecule gas that interacts with walls of the gas sampling and analysis equipment resulting in delayed instrument response. A set of experiments quantified various materials and process parameters of a heated sample line system for ammonia (NH3) response using a Fourier Transform infrared spectrometer (FTIR). Response attenuation rates are due to mixing and diffusion during transport as well as NH3 wall storage. Mixing/diffusion effects cause attenuation with a time constant 1-10 seconds. Wall storage attenuation has a time constant 10-200 seconds. The effects of sample line diameter and length, line temperature, line material, hydrated versus dry gas, and flow rate were examined. All of these factors are statistically significant to variation of at least one of the time constants. The NH3 storage on the sample system walls was calculated as a function of the experimental test as well. In this case, line length and diameter were not statistically significant, but line temperature, flow rate, and material were.
Technical Paper
2014-04-01
Yong-Wha Kim, Michiel Van Nieuwstadt, Greg Stewart, Jaroslav Pekar
Abstract This paper presents the application of model predictive control (MPC) to DOC temperature control during DPF regeneration. The model predictive control approach is selected for its advantage - using a model to optimize control moves over horizon while handling constraints. Due to the slow thermal dynamics of the DOC and DPF, computational bandwidth is not an issue, allowing for more complex calculations in each control loop. The control problem is formulated such that all the engine control actions, other than far post injection, are performed by the existing production engine controller, whereas far post injection is selected as the MPC manipulated variable and DOC outlet temperature as the controlled variable. The Honeywell OnRAMP Design Suite (model predictive control software) is used for model identification, control design and calibration. The paper includes description of the DPF regeneration process, model identification and validation results, control design and trade-off analysis and experimental validation of the controller on a Ford Superduty diesel truck.
Technical Paper
2014-04-01
Zhimin Liu, David Cleary
Abstract A 2.0L twin-scroll turbocharged SIDI engine was used to evaluate low-pressure loop water-cooled external EGR at operating conditions between 1000 rpm 75 Nm and 3000 rpm 250 Nm. The engine compression ratio was increased from 9.3 to 10.9. The maximum fuel consumption reduction potential, the boost pressure requirements, and the optimized external EGR calibration were determined. Combination of higher compression ratio and external EGR achieved 5-7% better fuel economy over mid-load region when using the twin-scroll turbocharger. A similar (4-6%) better fuel economy was observed over much of the higher-load region, including peak torque condition at 1000rpm, when the required boost pressure was provided by an externally-driven auxiliary boost system (not connected to the engine). The power consumption of auxiliary boost system (supercharger loss) was estimated and considered in fuel economy assessment. The fuel consumption reduction mechanisms of EGR were also analyzed. This study shows that reduced pumping loss attributed to about 0.5% fuel consumption reduction per 10% EGR, heat loss reduction and better mixture properties offered above 2% fuel consumption reduction per 10% EGR.
Technical Paper
2014-04-01
Georgios Fontaras, Panagiota Dilara, Michael Berner, Theo Volkers, Antonius Kies, Martin Rexeis, Stefan Hausberger
Due to the diversity of Heavy Duty Vehicles (HDV), the European CO2 and fuel consumption monitoring methodology for HDVs will be based on a combination of component testing and vehicle simulation. In this context, one of the key input parameters that need to be accurately defined for achieving a representative and accurate fuel consumption simulation is the vehicle's aerodynamic drag. A highly repeatable, accurate and sensitive measurement methodology was needed, in order to capture small differences in the aerodynamic characteristics of different vehicle bodies. A measurement methodology is proposed which is based on constant speed measurements on a test track, the use of torque measurement systems and wind speed measurement. In order to support the development and evaluation of the proposed approach, a series of experiments were conducted on 2 different trucks, a Daimler 40 ton truck with a semi-trailer and a DAF 18 ton rigid truck. Two different torque measurement systems (wheel rim torque sensors and half shaft torque sensors) were used for the measurements and two different vehicle tracking approaches were investigated (high precision GPS and opto-electronic barriers).
Technical Paper
2014-04-01
Stefan Schmidt, Maurice Smeets, Roland Boehner, Robert Aas, Christian Winkler, Markus Schoenen, Peter Hermann, Julian Tan, Magdi Khair, Joern Bullert
Tighter emission limits are discussed and established around the world to improve quality of the air we breathe. In order to control global warming, authorities ask for lower CO2 emissions from combustion engines. Lots of efforts are done to reduce engine out emissions and/or reduce remaining by suitable after treatment systems. Watlow, among others, a manufacturer of high accurate, active temperature sensor ExactSense™, wanted to understand if temperature sensor accuracy can have an influence on fuel consumption (FC). For this purpose a numerical approach was chosen where several non-road driving cycles (NRTCs) were simulated with the data base of a typical Stage IV heavy duty diesel engine. The engine is equipped with an exhaust gas after treatment system consisting of a DOC, CDPF and an SCR. In this work scope, the investigations shall be restricted to the FC benefits obtained in the active and passive DPF regeneration. The numerical investigations were performed using DPF soot loading and oxidation models using a commercially available software program.
Technical Paper
2014-04-01
Zhiming Gao, Tim J. LaClair, C. Stuart Daw, David E. Smith, Oscar Franzese
We present simulated fuel economy and emissions of city transit buses powered by conventional diesel engines and diesel-hybrid electric powertrains of varying size. Six representative city drive cycles were included in the study. In addition, we included previously published aftertreatment device models for control of CO, HC, NOx, and particulate matter (PM) emissions. Our results reveal that bus hybridization can significantly enhance fuel economy by reducing engine idling time, reducing demands for accessory loads, exploiting regenerative braking, and shifting engine operation to speeds and loads with higher fuel efficiency. Increased hybridization also tends to monotonically reduce engine-out emissions, but tailpipe (post-aftertreatment) emissions are affected by complex interactions between engine load and the transient catalyst temperatures, and the emissions results were found to depend significantly on motor size and details of each drive cycle.
Technical Paper
2014-04-01
Theodoros G. Vlachos, Pierre Bonnel, Adolfo Perujo, Martin Weiss, Pablo Mendoza Villafuerte, Francesco Riccobono
In-use testing with Portable Emissions Measurement Systems (PEMS) has received attention by policy makers and industry as an effective and cost-efficient means to verify emissions of a wide range of vehicles. We provide an overview of the state-of-the-art PEMS in-use emissions testing in the current and future European emissions legislation for light-duty and heavy-duty vehicles as well as non-road mobile machinery. For obtaining type approval in European Union (EU), light-duty vehicles have to comply with Euro 6 emission standards from January 2014 onward. In parallel, a new test procedure will complement standard emissions testing in the laboratory to control gaseous and particulate emissions over a wide range of real-world driving conditions. Two candidate procedures are developed at present, i.e., random cycle testing and on-road emissions testing with PEMS. Currently, key challenges are the definition of test conditions and design of a suitable method for data evaluation. For heavy-duty vehicles, in-use testing with PEMS is already enforced in the European Union since 2009.
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