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Technical Paper
2014-10-13
Jonathan Stewart, Andrew Woods, Roy Douglas, Richard O’Shaughnessy
With emission legislation becoming ever more stringent, automotive companies are forced to invest heavily in solutions to meet the targets set. To date, the most effective way of treating emissions is through the use of catalytic converters. Since the introduction of these converters as the main method of reducing automotive emissions, catalyst performance testing has become a major part of automotive research and development. One of the most critical aspects of the performance testing process is catalyst ageing. Legislation has been introduced stating that catalytic converters must meet the set emissions standards legislation up to a lifetime of 150,000 miles (LEV 2014-2022). The catalytic converter will deactivate over its lifetime due to a number of different factors, such as, thermal deactivation, poisoning, fouling and structural breakdown of the catalyst. It is therefore of the utmost importance for automotive companies to evaluate the performance of the catalytic converters under these conditions.
Technical Paper
2014-10-13
Kristin Götz, Anja Singer, Olaf Schröder, Christoph Pabst, Axel Munack, Jürgen Bünger, Jürgen Krahl
The political and economic major aim in Europe is the increase of the use of renewable energy resources up to 10 % till 2020. This means a reduction in crude oil dependency. Already well known in diesel fuel area are fatty acid methyl esters, named biodiesel. However, this biogenic component has not only advantages, as a further raise of the amount of biodiesel content in diesel fuel higher than seven percent can lead to an increase of the engine oil dilution in passenger cars with diesel particulate filters. Because of the regeneration of the particulate filters, the entry of fuel components increases. This may induce sludge formation in the engine oil. A promising approach to reduce this problem is a new type of biogenic fuel, called HVO (hydrotreated vegetable oil). This is also produced from vegetable oil or animal fat and it is chemically quite similar to fossil diesel fuel. Like biodiesel, HVO is free of sulfur or any aromatics. HVO has a higher cetane number in comparison to biodiesel and most diesel fuels.
Technical Paper
2014-10-13
Jon Andersson, John May, Cecile Favre, Dirk Bosteels, Simon de Vries, Matthew Heaney, Matthew Keenan, Jonathon Mansell
The exhaust emissions of two Euro 6 diesel cars with different emissions control systems have been evaluated both on the road and over various chassis dynamometer test cycles. European emissions limits are currently set using the New European Driving Cycle (NEDC), but the European Commission is preparing additional test procedures to ensure that emissions are well controlled both in real use and over the legislative test cycle. The main focus of this work on ‘Real Driving Emissions’ (RDE) is on measurements using Portable Emissions Measurement Systems (PEMS) in real, on-road driving. A key focus of a test programme undertaken for AECC (the Association for Emissions Control by Catalyst) by Ricardo was therefore the use of PEMS systems to measure on-road emissions of both gaseous pollutants and particulate matter. This included measurement of particle number emissions with a new candidate system for this type of measurement. The results from this testing are compared with emissions measured over four different chassis dynamometer test cycles – the current legislative cycle (New European Driving Cycle, NEDC); the Common Artemis suite of test cycles (CADC) that is widely used in emissions modelling; the new Worldwide Light-duty Test Cycle (WLTC) defined by the UN Working Party on Pollution and Energy (GRPE) as part of the development of the Worldwide harmonised Light vehicles Test Procedure (WLTP); and a set of cycles produced by a Random Cycle Generator based on ‘short trip’ segments from the EU database used to construct WLTC.
Technical Paper
2014-10-13
Achinta Varna, Konstantinos Boulouchos, Alexander Spiteri, Panayotis Dimopoulos Eggenschwiler, Yuri M. Wright
Simulations for a pressure-assisted multi-stream injector designed for urea-dosing in a selective catalytic reduction SCR exhaust gas system have been carried out and compared to measurements taken in an optically accessible high-fidelity flow test rig. The experimental data comprises four different combinations of mass flow rate and temperature for the gas stream with unchanged injection parameters for the spray. First, a parametric study is carried out to determine the importance of various spray sub-models, including atomization, spray-wall interaction, buoyancy as well as droplet coalescence. Optimal parameters are determined using experimental data for one reference operating condition. The model is subsequently applied to all operating conditions with unaltered parameters and validated by means of the measured droplet velocity fields, droplet diameter distributions and spray-tip propagation which have been characterized by means of Particle Image Velocimetry (PIV), Phase Doppler Anemometry (PDA) and shadowgraph imaging.
Technical Paper
2014-10-13
Rong Ma, Chao He, Jiaqiang Li
A simulation model of catalyzed diesel particulate filter (CDPF) is established based on the CFD software FIRE and has been validated through a series of experimental comparison. This model simulates the CDPF continuity regeneration process, and the factors that influence the exhaust NO2 concentration from CDPF including oxygen concentration, exhaust temperature, space velocity, proportion of NO2/NOX and soot mass fraction are studied. The results show that the higher oxygen concentration causes an increase in NO2/NOX. The NO2/NOX is significantly increased when the exhaust temperature is about 350℃. The space velocity in a certain degree leads higher NO2/NOX. There is no significant influence of increasing proportion of the NO2/NOX, and the soot mass fraction in the exhaust on the NO2/NOX at the CDPF outlet
Technical Paper
2014-10-13
Jonathan Stewart, Roy Douglas, Alexandre Goguet, Cristina Elena Stere, Luke Blades
Kinetic models are becoming an ever present tool in the development of automotive catalysis, primarily used for characterisation of catalysts and as a predictive tool for performance. This has led to a large number of kinetic models related to automotive catalysis appearing in literature in literature in the past decades. Most kinetic models for automotive application focus primarily on the global kinetic approach for reaction kinetics, with the more chemically accurate micro-kinetics appearing more frequently in the past number of years. One of the most critical aspects in the development of a kinetic model in general is the method used to control the switch between limiting factors over the period of the chemical reaction, namely mass transfer and reaction kinetics. This balance becomes increasingly more critical with the automotive application as the gas composition and gas flow vary throughout the automotive cycles resulting in a large number or reactions competing, with a constantly changing space velocity.
Technical Paper
2014-10-13
Mohammad Reza Hamedi, Athanasios Tsolakis, Jose Martin Herreros
Recent developments in diesel engines lead to increased fuel efficiency and reduced exhaust gas temperature. Therefore more energy efficient aftertreatment systems are required to comply with tight emission regulations. In this study, a computational fluid dynamics package was used to investigate the thermal behaviour of diesel aftertreatment system. A parametric study was carried out to identify the most influential piping material and insulation characteristics in terms of thermal performance. In case of aftertreatment piping and canning material effect, an array of different potential materials was selected and their effects on the emission conversion efficiency of a Diesel Oxidation Catalyst (DOC) were numerically investigated over a driving cycle. Results indicate that although the piping material volumetric heat capacity was decreased by a factor of four, the total emission reduction was only considerable during the cold start. Since the piping system heat up and cool down periods were accelerated by reducing the system thermal inertia.
Technical Paper
2014-10-13
S. F. Benjamin, C. A. Roberts
In an attempt to reduce particulate and NOx emissions from Diesel exhaust, the combined DPF and SCR filter is now frequently chosen as the preferred catalyst. When this device functions effectively it saves valuable packaging space in a passenger vehicle. As part of its development, modelling of its emissions performance is essential. Single channel modelling is the obvious choice for a DPF filter because of its complex geometry. This, however, can be computationally demanding. For a normal flow-through catalyst monolith the porous medium approach is an attractive alternative. This paper attempts to model an SCRF by applying the porous medium approach. The model is essentially 1D but as with all porous medium models, can very easily be applied to 3D cases once developed and validated. The model is described in full in this paper and values for all the key parameters are presented. The filter is assumed to collect soot in the inlet channels, but only the output channels are coated with SCR washcoat, as in the most recent devices.
Technical Paper
2014-10-13
Ossi Kaario, Teemu Sarjovaara, Olli Ranta, Tuomo Hulkkonen, Karri Keskinen, Martti Larmi, Sauli Halonen, Arno Amberla
In the present study, we analyze urea solution spray mixing and evaporation in a novel selective catalytic reduction (SCR) system. In typical SCR systems, low urea solution injection pressures are used. This may result in low evaporation rates implying that some additional methods need to be used to obtain feasible mixing and evaporation rates in the system. However, the aim in the present study is to use very high injection pressure for the solution in order to enhance droplet breakup, mixing, and evaporation and thus remove the need to use additional mixing enhancement techniques. We measure the spray characteristics of the urea solution, namely the spray penetration, opening angle, and droplet sizes from several distances from the nozzle and with various nozzle hole sizes and injection pressures. We focus our experiments on low gas density setting which is typically the SCR system operating environment. This kind of experimental data (low gas density, high injection pressure) is scarce in literature.
Technical Paper
2014-10-13
Andrew Pedlow, Geoffrey McCullough, Alexandre Goguet, Ken Hansen
Pedlow, A1). McCullough1), G. Goguet, A2). 1) School of Mechanical and Aerospace Engineering, Queen's University Belfast 2) School of Chemistry and Chemical Engineering, Queen's University Belfast Pedlow, A. Email: apedlow01@qub.ac.uk, Tel.: +4428 9097 4569 Mathematical modelling has become an essential tool in the design of modern catalytic systems. Emissions legislation is becoming increasingly stringent, meaning that mathematical models of after-treatment systems must become more accurate in order to provide confidence that a catalyst will convert pollutants over the required range of conditions in order to meet legislated limits. Automotive Catalytic converter models contain several sub-models that represent processes such as mass and heat transfer, and the rates at which the reactions proceed on the surface of the precious metal. Of these sub-models, the prediction of the surface reaction rates is by far the most challenging due to the complexity of the reaction system and the large number of gas species involved.
Technical Paper
2014-10-13
Anders Widd, Magnus Lewander
The Selective Catalytic Reduction (SCR) catalyst with ammonia as reducing agent plays a central role in today’s exhaust after-treatment systems for heavy-duty vehicles and there is a wide selection of possible catalytic materials to use. In order to facilitate the design of future catalysts, several aspects of the materials must be evaluated both in steadystate and transient operation. To this end, this paper presents a methodology for comparing the dynamic properties of different catalysts using full-size engine testing. The studied characteristics include the ammonia storage capacity, the effect on starting with an empty catalyst, the transient response to temperature gradients and changes in the urea dosing level. The temperature response is of particular importance in transient operation, where temperature increases may lead to substantial ammonia slip. A vanadium catalyst is compared to a Cu SAPO catalyst on the same substrate, and they show significant differences in their dynamic response.
Technical Paper
2014-10-13
Kohei Yoshida, Yusuke Nozaki, Toshihiro Mori, Yuki Bisaiji, Yuki Haba, Kazuhiro Umemoto, Takao Fukuma
To fulfill upcoming stringent worldwide CO2 emission target, engine thermal efficiency should further be increased and diesel engine is one of the promising solutions. Nevertheless to ensure good air quality, NOx emission should be reduced using a specific catalyst. In order to reduce NOx from a diesel engine operation in lean condition, Urea-Selective Catalyst Reduction (SCR) or NOx Storage and Reduction (NSR) systems have been widely adopted in the European market. The NSR system is most efficient for small/mid vehicle size since it requires less packaging space and it is less expensive than a urea SCR system. However, its NOx reduction performance is currently limited under high temperature and high space velocity conditions since the NOx storage ability as nitrate is insufficient under such conditions. For future NSR usage, it is therefore necessary to improve the NOx reduction performance of NSR. DiAir (Diesel NOx After-treatment by Adsorbed Intermediate Reductants) has been introduced as one of the measures to improve NOx conversion performance under high space velocity (SV) and temperature conditions.
Technical Paper
2014-10-13
Kihyung Joo, Jin Woo Park, Jin-ha Lee, Seok-Jae Kim, Seungbeom Yoo
In diesel engine development, the new technology is coming out to meet the stringent exhaust emission regulation. The regulation demands more eco-friendly vehicles. Euro6c demands to meet not only WLTP mode, but also RDE(Real Driving Emission). In order to satisfy RDE mode, the new technology to reduce emissions should cover all operating areas including High Load & High Speed. It is a big challenge to reduce NOx on the RDE mode and a lot of DeNOx technologies are being developed. So the new DeNOx technology is needed to cover widened operating area and strict acceleration/deacceleration. The existing LNT(Lean NOx Trap) and Urea SCR(Selective Catalytic Reduction) is necessary to meet the typical NEDC or WLTP, but the RDE mode demands the powerful DeNOx technology. Therefore, the LNT & Urea SCR on DPF was developed through this study. This complex new technology consists of new catalysts(to reduce emissions), insulation(to improve fuel economy, and catalytic performance) , and logical controller(to control DeNOx and DePM strategy).
Technical Paper
2014-10-13
Benjamin Kingsbury, Jonathan Stewart, Zhentao Wu, Roy Douglas, Kang Li
This study describes an innovative monolith structure designed for applications in automotive catalysis using an advanced manufacturing approach developed at Imperial College London. The production process combines extrusion with phase inversion of a ceramic-polymer-solvent mixture in order to design substrate micro-structures that offer improvements in performance, including reduced PGM loading, reduced catalyst ageing and reduced backpressure. The novel substrate is formed from hollow fibres which are fused together to form a ceramic monolith. A highly ordered micro-structure is present, formed from micro-channels which extend from the inner surface to the outer surface of the hollow fibres. The entrances to the micro-channels are in the range of 10 – 90 μm and are directly accessible to the exhaust gas as it passes along the substrate. The designed micro-structure generates a geometric surface area of 32,000 m²/m³, while at the same time achieving a 40-70 % reduction in pressure drop along the length of the substrate.
Technical Paper
2014-10-13
Tao Tang, Jun Zhang, Shi-jin Shuai, Dongxiao Cao
Selective catalytic reduction (SCR) has been demonstrated as one of the most promising technologies to reduce NOx emissions from heavy-duty diesel engines. To meet the Euro VI regulations, the SCR system should achieve high NOx reduction efficiency even at low temperature. In the SCR system, NH3 is usually supplied by the injection of urea water solution (UWS), therefore it is important to improve the evaporation and decomposition efficiency of UWS at low temperature and minimize urea deposits. In this study, the UWS spray, urea decomposition, and the UWS impingement on pipe wall at low temperature were investigated based on an engine test bench and computational fluid dynamics (CFD) code. The decomposition of urea and deposits was analyzed using thermal gravimetric analysis (TGA), differential scanning calorimetry (DSC) and fourier transform infrared spectroscopy (FTIR). The TGA experiment shows that urea decomposition started at about 150℃, and exhibited two stages of rapid mass loss.
Technical Paper
2014-10-13
Isaline Lefort, Jose Herreros, Athanasios Tsolakis
This study investigates the behaviour of a partial flow filter (PFF) under different engine operating conditions as well as the mechanisms governing the filtration efficiency depending on the particulate size. Some exhaust gas characteristics such as flow rate and engine-out particulate matter (PM) profile (size and concentration) were varied, which affected the total mass and number filtration efficiency of the partial flow filter. The effects of these exhaust characteristics were also different for the filtration of small (10-30 nm), medium (30-200 nm) or large particulates (200-400 nm). An increase in medium-large PM concentration reduced small size particulate filtration. On the other hand, the filtration of medium-large particulates remained unaffected when varying either small or medium-large exhaust PM concentrations. It was also observed that high space velocities promoted medium and large particulate filtration, while degrading the filter trapping efficiency for small particulates.
Technical Paper
2014-10-13
Chunxing Lin, Brian Hillman, Andrew Williams
Stringent IC engine PM emission regulation requires development of future filter substrate materials to achieve high filtration efficiency, low filter pressure drop, low cost and highly durable solutions. Monolithic wall flow filters perform well as they achieve high filtration efficiency due to the formation of the PM cake structure while maintaining low substrate face velocities due to the large filtration area. Within the process industry, MicroporeTM slotted metallic membrane filters offer both large surface areas and low filter pressure drops while maintaining the durability of metal substrates. The pore structure and pore arrangement can be readily tailored to suit specific applications. This paper characterizes a 300 μm thickness MicroporeTM metallic membrane with slots of 10 μm by 400 μm in size in the context of application as an engine exhaust particulate filter. The investigation was based on single layer of MicroporeTM slotted metallic membrane with size of 52 mm in diameter.
Technical Paper
2014-10-13
Aayush Mehrotra, Simhachalam Juttu, Siva Subramanian Ravishankar, Ghodke Pundlik Rambhaji, J G Suryawanshi
Cooling EGR & improving its mixing with air has given consistent improvement in diesel emissions, hence the evolution of superior cooling technologies & low pressure EGR helps in meeting stringent diesel emission norms. For the same volume of exhaust gas, cooled exhaust gas occupies lower volume for the same mass; thereby it is possible for engine to digest more amount of EGR or air depending upon the trade off and substantially improve the heat carrying capacity of exhaust gas. Lowering the temperature of EGR gives a great potential in reducing NOx and smoke in diesel engines, it helps in lowering the EGR mixture temperature and hence reducing the in cylinder temperature. An attempt has been made here to lower the EGR temperature downstream of a conventional cooler without changing the cooler design itself. For this, the source for coolant has been taken from radiator outlet unlike the conventional location of cylinder block. A 12 V electric pump circulates coolant to EGR cooler with a bypass from radiator; since the radiator outlet is much cooler than cylinder block outlet the cooling efficiency increases significantly.
Technical Paper
2014-10-13
Qian Feng, Diming Lou, Piqiang Tan, Zhiyuan Hu
In this study, durability and performance evaluation of the ageing catalyzed continuously regenerating trap (CCRT) on solid and volatile particulate emissions from urban diesel bus was studied by means of a set of on board measurement, transient TSI engine exhaust particle sizer spectrometer. During fourteen months, the CCRT had successfully reached self-regeneration. Three typical urban bus operating conditions, idling, stepped steady and transient conditions were carried out on-real world tests. In all evaluation tests, the average filtration efficiency of particle number was 93.3% at least under idling and stepped steady conditions. The CCRT of different ageing phase had different effect on nuclei mode particle. As the CCRT aging increase, the total particle number concentrations showed a declining trend while proportion of nuclei mode number concentration presented rising trend increasingly. This’s mainly due to the development of filtration mechanism: deep bed filtration, transitory and granular bed filtration.
Technical Paper
2014-10-13
Z. Gerald Liu, Dana McGuffin, Chris M. Cremeens, Nathan Ottinger, Niklas Schmidt
More stringent emission requirements for nonroad diesel engines both in the U.S. and Europe have spurred the development of exhaust aftertreatment technologies. In this study, one such system consisting of a diesel oxidation catalyst, zeolite-based selective catalytic reduction catalyst, and an ammonia oxidation catalyst was evaluated using both nonroad transient and steady-state cycles in order to understand the emission characteristics of this configuration. Criteria pollutants were analyzed and particular attention was given to organic compound and NO2 emissions since both of these could be significantly affected by the absence of a diesel particulate filter that typically helps reduce semi-volatile and particle-phase organics and consumes NO2 via passive soot oxidation. Results are then presented on a detailed speciation of organic emissions including alkanes, cycloalkanes, aromatics, polycyclic aromatic hydrocarbons and their derivatives, and hopanes and steranes. It is shown that each of these groups of species was reduced significantly in comparison to engine out levels.
Technical Paper
2014-09-30
Britney J. McCoy, Arman Tanman
In-use testing of verified diesel emission control technologies is an integral component of EPA’s verification program. Device manufacturers are required to complete in-use testing once 500 units have been sold. Additionally, EPA conducts test programs on randomly selected retrofit devices from installations used within the National Clean Diesel Campaign grant programs. In this test program, EPA identified and recovered a variety of retrofit devices installed on heavy-duty diesel vehicles (on-highway and off-road) including diesel particulate filters (DPFs) and diesel oxidation catalysts (DOCs). All of the devices were tested at Southwest Research Institute. The goal was to evaluate the emissions performance and durability of retrofit technologies aged in real-world applications. In assessing the emissions reducing performance of these after-treatment technologies, a variety of different test methods were used to characterize the overall performance of the retrofit devices on an engine dynamometer.
Technical Paper
2014-09-30
Manoj K. Sampath, Figen Lacin
Diesel engine combustion process results in harmful exhaust emissions mainly composed of Particulate Matter (PM), Hydro Carbon (HC), Carbon monoxide (CO) and Nitrogen Oxides (NOx). Several technologies utilizing catalyst has been developed in the past decades to control these diesel emissions. Reduction of PM by advanced combustion research often results in increase of NOx due to more complete combustion and hence reducing NOx becomes even more challenging. One of the promising and well matured technology of reducing NOx is to implement Selective Catalytic Reduction (SCR) using ammonia (NH3) as the reducing agent. The generation of NH3, in this case, is from the evaporation of Diesel Exhaust Fluid (DEF) or liquid urea through thermolysis and hydrolysis process. For an effective SCR system, the mal-distribution of ammonia across the SCR Inlet has to be evenly distributed. There are several commercial Computational Fluid Dynamics (CFD) tools available to predict the SCR flow distribution including ammonia formation from the urea decomposition.
Technical Paper
2014-09-30
Alexander Sappok, Leslie Bromberg
Diesel Particulate Filters (DPF) are a key component in many on- and off-road aftertreatment systems to meet increasingly stringent particle emissions limits. Efficient thermal management and regeneration control is critical for reliable and cost-effective operation of the combined engine and aftertreatment system. Conventional control DPF control systems predominantly rely on a combination of filter pressure drop measurements and predictive models to indirectly estimate the soot loading state of the filter. Over time, the build-up of incombustible ash, primarily derived from metal-continuing lubricant additives, accumulates in the filter to levels far exceeding the DPF’s soot storage capacity. The combined effects of soot and ash build-up dynamically impact the filter’s pressure drop response, service life, and fuel consumption, and must be accurately accounted for to optimize engine and aftertreatment system performance. This work applied a radio frequency (RF) sensor to directly monitor diesel particulate filter soot and ash levels, thereby enabling direct feedback control of the filter based on its actual loading state.
Technical Paper
2014-09-30
Zhiguo Zhao, Guanyu Zheng, Fengshuang Wang, Suying Zhang, Jianhua Zhang
In order to satisfy China IV emissions regulations, an unique design was proposed with injector closely coupled with SCR outer body. The benefit of this design is that the system mixing pipe can be shortened, resulting in smaller packaging space and lower cost of decomposition pipe. However, the shorter urea mixing distance generates concerns on lower urea mixing efficiency and higher risks of urea deposits. Aftertreatment systems need to be properly engineered to resolve these technical challenges. Systematic enhancements of the design have been performed to enable multiple designs to meet a set of performance targets, including emission reduction efficiency via improved reagent mixing, evaporation, distribution, back pressure, and removing of urea deposits. The optimized system improved NOx reduction uniformity, eliminated urea deposits, improved NOx conversion efficiency while satisfy existing installation packing space. This study demonstrates that good system performance can be achieved despite the challenges of meeting strict and often-conflicting performance targets.
Technical Paper
2014-09-30
Guanyu Zheng, Fengshuang Wang, Sheng Wang, Wei Gao, Zhiguo Zhao, Jian Liu, Lin Wang, Lin Wu, Hongyu Wang
Urea-based SCR has been the mainstream technology to reduce NOx emissions for on-road vehicles and off-road vehicles. In category II marine applications, urea SCR is being considered as an enabling technology to reduce NOx. A typical urea SCR system includes a urea injector, injector housing, mixer, and appropriate pipe configurations. In applications of the SCR technology, urea mixing and deposit mitigation have become severe challenges. Urea deposit issues were encountered in SCR systems designed for large marine engines. To resolve urea deposits, CFD method and tests were applied to investigate urea spray transport, evaporation and droplet-wall phenomena. In system design, multiple design factors are reviewed: (1) overall geometrical layouts; (2) substrate and catalyst selections; (3) urea injector and nozzle selections; (4) miscellaneous issues such as ash cleaning, fuel switching, and etc.
Technical Paper
2014-09-30
Ashish Kumar Singh, Abhishek Sharma, Naveen Kumar
Fast depletion of fossil fuels is urgently demanding a carry out work for research to find out the viable alternative fuels for meeting sustainable energy demand with minimum environmental impact. In the future, our energy systems will need to be renewable and sustainable, efficient and cost-effective, convenient and safe. Therefore, researcher has shown interest towards alternative fuels like vegetable oils, alcoholic fuels, LPG, CNG, Producer gas, biogas in order to substitute conventional fuels used in compression ignition (CI) engine. However studies have suggested that trans-esterified vegetable oils retain quite similar physico-chemical properties comparable to diesel. Besides having several advantages, its use is restricted due to trouble like higher NOx emission and engine deposit due to partially incomplete combustion. There is a need of cleaner fuel for diesel engines in the present rigid emissions norms and the fossil depletion. In the current analysis CNG with KOME is used in dual fuel mode for complete combustion of charge so as to reduce emission.
Technical Paper
2014-09-30
Zhiming Gao, Charles Finney, Charles Daw, Tim J. LaClair, David Smith
Two hybrid powertrain configurations, including parallel and series hybrids, were simulated for fuel economy, component energy loss, and emissions control in Class 8 trucks over both city and highway driving conditions. A comprehensive set of component models describing engine fuel consumption, emissions control, battery energy, and accessory power demand interactions was developed and integrated with the simulated hybrid trucks to identify heavy-duty (HD) hybrid technology barriers. The results show that series hybrid is absolutely negative for fuel-economy improvement of long-haul trucks due to an efficiency penalty associated with the dual-step conversions of energy (i.e. mechanical to electric to mechanical). The current parallel hybrid technology combined with 50% auxiliary load reduction could improve fuel economy by 5-7% in long-haul trucks, but a profound improvement of long-haul truck fuel economy requires innovative technologies for reducing aerodynamic drag and rolling resistance.
Technical Paper
2014-09-30
Steffen Hoppe, Troy Kantola
Increasingly, the fundamental drivers in the development of commercial vehicle engines are improved fuel efficiency and the need to meet more stringent exhaust emissions legislation. This strategy presents significant challenges in the development of engine components, particularly piston rings. Within the power cylinder, piston rings are significant contributors to friction losses, with the ring pack contributing up to 25 percent of the total mechanical engine friction loss, and a corresponding fuel consumption of up to four percent. The challenge lies in reducing friction power loss while also mastering the increasing thermomechanical and tribological demands that piston rings must endure due to increased power density, smoother cylinder bores, reduced lubrication, and the use of alternative fuels. In this context, the robustness of the piston ring running face, as characterized by wear resistance and scuff resistance in particular, plays an increasing role. As coatings are a crucial surface design element, they inevitably are a primary focus for addressing friction loss and increasing robustness in the piston ring/cylinder tribological system.
Technical Paper
2014-09-30
Antoine Delorme, Jason L. Robert, William Eli Hollowell, Andre M. Strobel, Jason T. Krajewski
In the recent years, Automated Manual Transmissions have become more popular for class 8 heavy trucks. Besides the benefits of smoother gear changes and reduced driver fatigue, AMTs can also greatly reduce fuel consumption by using optimized shifting strategies and advanced controls. The Detroit DT12 AMT demonstrated significant fuel savings due in part to its eCoast feature. eCoast relies on intelligent and advanced electronic controls to safely allow the vehicle to coast on downgrades. While the engine is idling, the drag parasitic energy losses are decreased and the vehicle can fully use its momentum to travel further up and down hill. As one could expect, the type of route profile can greatly affect the fuel savings due to eCoast, since more hilly terrains might offer more opportunities to activate eCoast than flatter roads. In addition, when combined with different vehicle and driving parameters such as vehicle weight and driver desired cruise set speed, the fuel consumption reduction of eCoast is always there, but becomes a more complicated function.
Technical Paper
2014-09-30
L. Joseph Bachman, Anthony Erb, Jeffry Sellers
Road tests of class 8 tractor trailers were conducted on new and retreaded tires of varying rolling resistance in order to provide estimates of the quantitative relation between rolling resistance and fuel consumption. Reductions in fuel consumption were estimated using the SAE J1321 (reaffirmation of 1986) test method. Vehicle rolling resistance was calculated as a load-weighted average of the rolling resistance (as measured by ISO28580) of the tires in each axle position. Both new and retreaded tires were tested in different combinations to obtain a range of vehicle coefficient of rolling resistance from a baseline of 7.7 kg/ton to 5.3 kg/ton. Reductions in fuel consumption displayed a strong linear relationship with coefficient of rolling resistance, with a maximum reduction of fuel consumption of 10 per cent relative to the baseline. The return factor for the new tires was 3.1:1, that is a 3.1 per cent decrease in rolling resistance yielded a fuel consumption decrease of 1 per cent.
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