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2015-04-14
Journal Article
2015-01-0391
Yoshihiro Sukegawa, Kazuhiro Oryoji
Abstract A 3D simulation technique to estimate density of particulate matter (PM) from spark ignition (SI) gasoline engines is proposed. The technique is based on a two-equation model consisting of coupled conservation equations of soot particle number and mass and fluid transportation equations. The nucleation rate of soot particles was obtained from a database built by simulation of elementary reaction with the proposed technique. Two approaches were explored to obtain the nucleation rate. One involves 0-dimensinal SI simulation and the other involves 1-dimensinal flame propagation simulation. The estimation results were verified with measurement data obtained with a single cylinder SI engine a homogeneous pre-mixed fuel was supplied. It was confirmed that appropriate results could be obtained with the 1-dimensional approach for the nucleation rate model.
2015-04-14
Journal Article
2015-01-0440
Julio Carrera, Alfredo Navarro, Concepcion Paz, Alvaro Sanchez, Jacobo Porteiro
Recent emissions standards have become more restrictive in terms of CO2 and NOx reduction. This has been translated into higher EGR rates at higher exhaust gas temperatures with lower coolant flow rates for much longer lifetimes. In consequence, thermal load for EGR components, specially EGR coolers, has been increased and thermal fatigue durability is now a critical issue during the development. Consequently a new Thermo-Mechanical Analysis (TMA) procedure has been developed in order to calculate durability. The TMA calculation is based on a Computational Fluid Dynamics simulation (CFD) in which a boiling model is implemented for obtaining realistic temperature predictions of the metal parts exposed to possible local boiling. The FEM model has also been adjusted to capture the correct stress values by submodeling the critical areas. Life calculation is based on a Multiaxial Fatigue Model that has also been implemented in FEM software for node by node life calculation.
2015-04-14
Journal Article
2015-01-0890
Barbara Graziano, Florian Kremer, Stefan Pischinger, Karl Alexander Heufer, Hans Rohs
Abstract The current and future restrictions on pollutant emissions from internal combustion engines require a holistic investigation of the abilities of alternative fuels to optimize the combustion process and ensure cleaner combustion. In this regard, the Tailor-made Fuels from Biomass (TMFB) Cluster at Rheinisch-Westfälische Technische Hochschule (RWTH) Aachen University aims at designing production processes for biofuels as well as fuels optimal for use in internal combustion engines. The TMFB Cluster's scientific approach considers the molecular structure of the fuels as an additional degree of freedom for the optimization of both the production pathways and the combustion process of such novel biofuels. Thus, the model-based specification of target parameters is of the utmost importance to improve engine combustion performance and to send feedback information to the biofuel production process.
2015-04-14
Technical Paper
2015-01-0889
Jai Gopal Gupta, Avinash Kumar Agarwal
Abstract Use of biodiesel from non-edible vegetable oil as an alternative fuel to mineral diesel is attractive economically and environmentally. Diesel engines emit several harmful gaseous emissions and some of them are regulated worldwide, while countless others are not regulated. These unregulated species are associated with severe health hazards. Karanja biodiesel is a popular alternate fuel in South Asia and various governments are considering its large-scale implementation. Therefore it is important to study the possible adverse impact of this new alternate fuel. In this study, unregulated and regulated emissions were measured at varying engine speeds (1500, 2500 and 3500 rpm) for various engine loads (0%, 20%, 40%, 60%, 80% and 100% rated load) using 20% Karanja biodiesel blend (KB20) and diesel in a 4-cylinder 2.2L common rail direct injection (CRDI) sports utility vehicle (SUV) engine.
2015-04-14
Journal Article
2015-01-0892
Alastair Smith, Rod Williams
Abstract The formation of deposits within injector nozzle holes of common-rail injection fuel systems fitted to modern diesel cars can reduce and disrupt the flow of fuel into the combustion chamber. This disruption in fuel flow results in reduced or less efficient combustion and lower power output. Hence there is sustained interest across the automotive industry in studying these deposits, with the ultimate aim of controlling them. In this study, we describe the use of Scanning Electron Microscopy (SEM) imaging to characterise fuel injector hole deposits at intervals throughout an adaptation of the CEC Direct Injection Common Rail Diesel Engine Nozzle Coking Test, CEC F-98-08 (DW10B test)[1]. In addition, a similar adaptation of a previously published Shell vehicle test method [2] was employed to analyse fuel injector hole deposits from a fleet of Euro 5 vehicles.
2015-04-14
Technical Paper
2015-01-0896
Antoine Lacarriere, Thierry Seguelong, Virginie Harle, Clara Fabre
Abstract Since Euro 5 standard, Diesel Particulate Filter (DPF) technology has been widely introduced in Europe and Fuel Borne Catalysts (FBC) provide a powerful solution to achieve regeneration in all driving conditions. Ongoing new emission regulation constraints of Euro 6.b (2014) and forthcoming Euro 6.c standard in 2017, that will reduce the gap between emissions during homologation and in real driving conditions, will demand the support of optimized FBC formulated with Deposit Control Additive (DCA). This paper presents the impact on DPF regeneration performance of advanced FBC with a sharp particle size distribution of reduced nanoparticle size diameter. Small particle size FBC gives enhanced DPF regeneration, allowing regeneration at lower temperature (i.e. improving fuel economy) but also lower dosing rates in fuel. Thus, this implies reduced filter ash content and an extended maintenance interval.
2015-04-14
Technical Paper
2015-01-0895
Senthilkumar Masimalai, Venkatesan Kuppusamy, Jaikumar Mayakrishnan
Abstract This paper aims at studying the effect of oxygen enriched combustion on performance, emission and combustion characteristics of a diesel engine using waste cooking oil (WCO) derived from palm oil as fuel. A single cylinder water-cooled, direct injection diesel engine was used. The intake system of the engine was modified to accommodate excess oxygen in the incoming air. Base data was generated using diesel as fuel. Subsequently experiments were repeated with WCO for different oxygen concentrations such as 21% (WCO+21%O2), 23% (WCO+23%O2), 24% (WCO+24%O2) and 25% (WCO+25%O2) by volume. Engine performance, emission and combustion parameters were obtained at different power outputs and analyzed. Results showed reduced brake thermal efficiency, higher smoke, hydrocarbon and carbon monoxide emissions with WCO+21%O2 as compared to diesel at all power outputs.
2015-04-14
Technical Paper
2015-01-0909
Karthik Nithyanandan, Jiaxiang Zhang, Li Yuqiang, Han Wu, Chia-Fon Lee
Abstract Alcohols, especially n-butanol, have received a lot of attention as potential fuels and have shown to be a possible alternative to pure gasoline. The main issue preventing butanol's use in modern engines is its relatively high cost of production. ABE, the intermediate product in the ABE fermentation process for producing bio-butanol, is being studied as an alternative fuel because it not only preserves the advantages of oxygenated fuels, but also lowers the cost of fuel recovery for individual component during fermentation. With the development of advanced ABE fermentation technology, the volumetric percentage of acetone, butanol and ethanol in the bio-solvents can be precisely controlled. In this respect, it is desirable to estimate the performance of different ABE blends to determine the best blend and optimize the production process accordingly.
2015-04-14
Technical Paper
2015-01-0914
Ehsan Tootoonchi, Gerald Micklow
Abstract Understanding the physics and chemistry involved in diesel combustion, with its transient effects and the inhomogeneity of spray combustion is quite challenging. Great insight into the physics of the problem can be obtained when an in-cylinder computational analysis is used in conjunction with either an experimental program or through published experimental data. The main area to be investigated to obtain good combustion begins with the fuel injection process and the mean diameter of the fuel particle, injection pressure, drag coefficient, rate shaping etc. must be defined correctly. The increased NOx production and reduced power output found in engines running biodiesel in comparison to petrodiesel is believed to be related to the different fuel characteristics in comparison to petroleum based diesel. The fuel spray for biodiesel penetrates farther into the cylinder with a smaller cone angle. Also the fuel properties between biodiesel and petrodiesel are markedly different.
2015-04-14
Technical Paper
2015-01-0898
Leonardo Pellegrini, Carlo Beatrice, Gabriele Di Blasio
Abstract Hydrotreated vegetable oil (HVO) is a renewable high quality paraffinic diesel that can be obtained by the hydrotreating of a wide range of biomass feedstocks, including vegetable oils, animal fats, waste oils, greases and algal oils. HVO can be used as a drop-in fuel with beneficial effects for the engine and the environment. The main objective of this study was to explore the potential of HVO as a candidate bio blendstock for new experimental formulations of diesel fuel to be used in advanced combustion systems at different compression ratios and at high EGR rates in order to conform to the Euro 6 NOx emission standard. The experiments were carried out in a single-cylinder research engine at three steady-state operating conditions and at three compression ratios (CR) by changing the piston.
2015-04-14
Technical Paper
2015-01-1020
Joel Michelin, Philippe Nappez, Frederic Guilbaud, Christof Hinterberger, Eric Ottaviani, Catherine Gauthier, Philippe Maire, Thierry Couturier
Abstract Future Diesel emission standards for passenger cars, light and medium duty vehicles, require the combination of a more efficient NOx reduction performance, a significant reduction of fuel consumption along with the opportunity to reduce the complexity and the package requirements to facilitate it. Recent activities on catalytic products allows for the SCR active compounds to move from the ceramic substrate located in the underbody to the DPF substrate already located in a close coupled position to achieve the benefit of the highest temperature. This newly developed SCR-coated DPF has massively improved the potential of NOX reduction. As published in the SAE-2014-0132 “advanced compact mixer: BlueBox” [1] it is crucial to inject Adblue®/DEF with a very high mixing performance level.
2015-04-14
Technical Paper
2015-01-1019
Changpu Zhao, Man Bai, Junwei Yang, Fang Shang, Gang Yu
Abstract The main objective of this paper was to investigate the pressure drop characteristics of ACT (asymmetric cell technology) design filter with various inlet mass flow rates, soot loads and ash loads by utilizing 1-D computational Fluid Dynamics (CFD) method. The model was established by AVL Boost code. Different ratios of inlet to outlet channel width inside the DPF (Diesel Particulate Filter) were investigated to determine the optimal structure in practical applications, as well as the effect of soot and ash interaction on pressure loss. The results proved that pressure drop sensitivity of different inlet/outlet channel width ratios increases with the increased inlet mass flow rate and soot load. The pressure drop increases with the increased channel width ratio at the same mass flow rate. When there is little soot deposits inside DPF, the pressure drop increases with the bigger inlet.
2015-04-14
Technical Paper
2015-01-1033
Raymond Conway, Sougato Chatterjee, Mojghan Naseri, Ceren Aydin
Abstract Selective Catalytic Reduction (SCR) catalysts have been demonstrated as an effective solution for controlling NOx emissions from diesel engines. Typical 2013 Heavy Duty Diesel emission control systems include a DOC upstream of a catalyzed soot filter (CSF) which is followed by urea injection and the SCR sub-assembly. There is a strong desire to further increase the NOx conversion capability of such systems, which would enable additional fuel economy savings by allowing engines to be calibrated to higher engine-out NOx levels. One potential approach is to replace the CSF with a diesel particulate filter coated with SCR catalysts (SCRF® technology, hereafter referred to as SCR-DPF) while keeping the flow-through SCR elements downstream, which essentially increases the SCR volume in the after-treatment assembly without affecting the overall packaging.
2015-04-14
Technical Paper
2015-01-1031
Nic van Vuuren, Gabriele Brizi, Giacomo Buitoni, Lucio Postrioti, Carmine Ungaro
Abstract The recent implementation of new rounds of stringent nitrogen oxides (NOx) emissions reduction legislation in Europe and North America is driving the expanded use of exhaust aftertreatment systems, including those that treat NOx under the high-oxygen conditions typical of lean-burn engines. One of the favored aftertreatment solutions is referred to as Selective Catalytic Reduction (SCR), which comprises a catalyst that facilitates the reactions of ammonia (NH3) with the exhaust nitrogen oxides (NOx). It is customary with these systems to generate the NH3 by injecting 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.
2015-04-14
Technical Paper
2015-01-1024
Hisao Haga, Hiroyuki Kojima, Naoko Fukushi, Naoki Ohya, Takuya Mito
Abstract A diesel engine is possible solution for carbon dioxide (CO2) reduction from automobiles. However, it is necessary for a diesel engine vehicle to reduce nitrogen oxide (NOx) emission. Therefore, this research focused on a Urea-selective catalytic reduction (urea-SCR) system as an after-treatment system to convert NOx and proposes the control method of the urea-SCR system based on the output of an ammonia (NH3) sensor. By maximizing NH3 storage rate of the SCR, conversion performance is maximized. To maximize the NH3 storage rate, an NH3 sensor is installed downstream of the SCR. The amount of urea-solution is controlled to keep NH3 slip detected by the sensor. Thus, the NH3 storage amount in the SCR or the SCRF (SCR on filter) can be maximized. The estimation and the control of NH3 storage amount is also used to cause NH3 slip immediately. NH3 storage capacity changes with catalyst temperature. In a transient state, temperature distribution occurs in the SCR catalyst.
2015-04-14
Journal Article
2015-01-1027
David Culbertson, Magdi Khair, Sanhong Zhang, Julian Tan, Jacob Spooler
Abstract SCR cold-start effects are increasingly important for meeting today's emission requirements [1]. A significant challenge toward quickly achieving NOx abatement is the presence of moisture in the catalyst at lower temperatures [1]. This paper describes the ability of an electric heater to effectively raise the temperature of the exhaust and overcome the effect of moisture and low exhaust temperature, allowing NOx conversion to begin sooner. A model of the moisture storage and removal is presented, along with results from engine tests. Results show that it is possible to achieve high NOx conversion temperatures quickly with robust heater technology that is suited for diesel applications.
2015-04-14
Technical Paper
2015-01-1003
Tomohito Kakema, Yukio Suehiro, Yoshiaki Matsuzono, Takeshi Narishige, Masanori Hashimoto
Abstract This research is aimed at development of the catalyst for gasoline automobiles which uses only palladium (Pd) among platinum group metals (PGMs). And the conformity emission category aimed at LEV III-SULEV30. For evaluation, the improvement effect was verified for 2013 model year (MY) ACCORD (LEV II-SULEV) as the reference. As compared with Pd-rhodium (Rh) catalyst, a Pd-only catalyst had the low purification performance of nitrogen oxides (NOx), and there was a problem in the drop in dispersion of Pd by sintering, and phosphorus (P) poisoning.
2015-04-14
Journal Article
2015-01-1004
Joseph R. Theis, Jeong Kim, Giovanni Cavataio
Abstract A laboratory study was performed to assess the potential capability of passive TWC+SCR systems to satisfy the Tier 2, Bin 2 emission standards for lean-burn gasoline applications. In this system, the TWC generates the NH3 for the SCR catalyst from the feedgas NOx during rich operation. Therefore, this approach benefits from high feedgas NOx during rich operation to generate high levels of NH3 quickly and low feedgas NOx during lean operation for a low rate of NH3 consumption. It was assumed that the exhaust system needed to include a close-coupled (CC) TWC, an underbody (U/B) TWC, and an U/B SCR converter to satisfy the emission standards during the FTP and US06 tests while allowing lean operation for improved fuel economy during select driving conditions. Target levels for HC, CO, and NOx during lean/rich cycling were established.
2015-04-14
Technical Paper
2015-01-1005
Masahide Miura, Yuki Aoki, Nobusuke Kabashima, Takahiko Fujiwara, Toshitaka Tanabe, Akira Morikawa, Hirotaka Ori, Hiroki Nihashi, Suguru Matsui
Abstract Countries and regions around the world are tightening emissions regulations in reaction to the increasing awareness of environmental conservation. At the same time, growing concerns about the depletion of raw materials as vehicle ownership continues to increase is prompting automakers to look for ways of decreasing the use of platinum-group metals (PGMs) in the exhaust systems. This research has developed a new catalyst with strong robustness against fluctuations in the exhaust gas and excellent nitrogen oxide (NOx) conversion performance. This catalyst incorporates rhodium (Rh) clusters with a particle size of several nanometers, and stabilized CeO2-ZrO2 solid-solution (CZ) with a pyrochlore crystal structure as a high-volume oxygen storage capacity (OSC) material with a slow O2 storage rate.
2015-04-14
Journal Article
2015-01-1006
Joseph R. Theis, Jeong Kim, Giovanni Cavataio
Abstract A laboratory study was performed to assess the potential capability of TWC+LNT/SCR systems to satisfy the Tier 2, Bin 2 emission standards for lean-burn gasoline applications. It was assumed that the exhaust system would need a close-coupled (CC) TWC, an underbody (U/B) TWC, and a third U/B LNT/SCR converter to satisfy the emission standards on the FTP and US06 tests while allowing lean operation for improved fuel economy during select driving conditions. Target levels for HC, CO, and NOx during lean/rich cycling were established. Sizing studies were performed to determine the minimum LNT/SCR volume needed to satisfy the NOx target. The ability of the TWC to oxidize the HC during rich operation through steam reforming was crucial for satisfying the HC target.
2015-04-14
Technical Paper
2015-01-1000
Anna Fathali, Fredrik Wallin, Annika Kristoffersson, Mats Laurell
Abstract The objective of this study was to investigate which of the artificial aging cycles available in the automotive industry that causes major deactivation of three-way catalysts (TWCs) and can be used to obtain an aged catalyst similar to the road aged converter (160 000km). Standard bench cycle (SBC) aging with secondary air injection (SAI) covered aging with various mass flows - a flow from three cylinders into one catalyst system and a flow from three cylinders into two parallel connected catalysts. For rapid catalyst bench aging, secondary air injection is a very efficient tool to create exotherms. Furthermore, the effect on catalytic activity of SAI aging with poisons from oil and fuel dopants (P, Ca, Zn) was investigated. The catalysts were thoroughly characterized in light-off and oxygen storage capacity measurements, emission conversion as a function of lambda and load variation was determined.
2015-04-14
Technical Paper
2015-01-1001
Shinichiro Otsuka, Yukio Suehiro, Hiroshi Koyama, Yoshiaki Matsuzono, Cameron Tanner, David Bronfenbrenner, Tinghong Tao, Kenneth Twiggs
Abstract With the increasing number of automobiles, the worldwide problem of air pollution is becoming more serious. The necessity of reducing tail-pipe emissions is as high as ever, and in countries all over the world the regulations are becoming stricter. The emissions at times such as after engine cold start, when the three-way catalyst (TWC) has not warmed up, accounts for the majority of the emissions of these pollutants from vehicles. This is caused by the characteristic of the TWC that if a specific temperature is not exceeded, TWC cannot purify the emissions. In other words, if the catalyst could be warmed up at an early stage after engine start, this would provide a major contribution to reducing the emissions. Therefore, this research is focused on the substrate weight and investigated carrying out major weight reduction by making the porosity of the substrate larger than that of conventional products.
2015-04-14
Journal Article
2015-01-1002
Yuichiro Murata, Tomoko Morita, Katsuji Wada, Hiroshi Ohno
Abstract A new concept for trapping NOx and HC during cold start, the NOx Trap Three-Way Catalyst (N-TWC), is proposed. N-TWC adsorbs NOx at room temperature, and upon reaching activation temperature under suitable air-fuel ratio conditions, it reduces the adsorbed NOx. This allows a reduction in NOx emissions during cold start. N-TWC's reduction mechanism relies on NOx adsorption sites which are shown to be highly dispersed palladium on acid sites in the zeolite. Testing on an actual vehicle equipped with N-TWC confirmed that N-TWC is able to reduce emissions of NOx and HC during cold start, which is a challenge for conventional TWCs.
2015-04-14
Technical Paper
2015-01-1011
Kazutake Ogyu, Toyoki Ogasawara, Yuichi Nagatsu, Yuya Yamamoto, Tatsuhiro Higuchi, Kazushige Ohno
Abstract The Particle Number (PN) emission limit is implemented for Direct Injection (DI) gasoline from EU6 regulation in European region. The wall-flow type ceramic filter technology is an essential component for Diesel PN emission control, and will be one potential solution to be investigated for the future Gasoline DI PN emission control demand. Especially the requirement of lower pressure loss with smaller filter volume is very strong for the filter substrate for Gasoline DI compared to DPF, not to lose better fuel economy benefit of Gasoline DI engine. Re-crystallized SiC (R-SiC) has high strength as its own property, and enable for Gasoline Particulate Filter (GPF) design to make the wall thickness thinner and the porosity higher compared to the other ceramic materials.
2015-04-14
Technical Paper
2015-01-1015
Guanyu Zheng, Jianhua Zhang, Fengshuang Wang, Kaihua Zhao
Multiple suppliers have developed new cordierite 10.5″ OD substrates in China market. One key issue is to evaluate the feasibility of their applications to diesel SCR markets. To this end, test procedures were conceived and performed towards multiple substrate characteristics. Besides typical parameters such as product dimensions, structures, and material strength, thermo-mechanical properties were characterized by hot vibration, thermal shock and thermal cycle tests. Flow performance before and after tests was characterized by a hot flow bench. Four suppliers were selected to provide product samples which went through these developed rigorous test procedures. Comparisons of multiple properties were made. Conclusions regarding their applicability and recommendations for future work are provided at the end.
2015-04-14
Technical Paper
2015-01-1013
Shankar Ramadas, Sunil Prasanth Suseelan, Thiyagarajan Paramadhayalan, Ambalavanan Annamalai, Rahul Mital
Abstract Emission compliance at the production level has been a challenge for vehicle manufacturers. Diesel oxidation catalyst (DOC) plays a very important role in controlling the emissions for the diesel vehicles. Vehicle manufacturers tend to ‘over design’ the diesel oxidation catalyst to ‘absorb’ the production variations which seems an easier and faster solution. However this approach increases the DOC cost phenomenally which impacts the overall vehicle cost. The main objective of this paper is to address the high variation in CO tail pipe emissions which were observed on a diesel passenger car during development. This variation was posing a challenge in consistently meeting the internal product requirement/specification.
2015-04-14
Technical Paper
2015-01-1008
Vitaly Y. Prikhodko, Josh A. Pihl, Todd J. Toops, John F. Thomas, James E. Parks, Brian H. West
Abstract Ethanol is a very effective reductant for nitrogen oxides (NOX) over silver/alumina (Ag/Al2O3) catalysts in lean exhaust environments. With the widespread availability of ethanol/gasoline-blended fuel in the U.S., lean gasoline engines equipped with Ag/Al2O3 catalysts have the potential to deliver higher fuel economy than stoichiometric gasoline engines and to increase biofuel utilization while meeting exhaust emissions regulations. In this work a pre-commercial 2 wt% Ag/Al2O3 catalyst was evaluated on a 2.0-liter BMW lean burn gasoline direct injection engine for the selective catalytic reduction (SCR) of NOX with ethanol/gasoline blends. The ethanol/gasoline blends were delivered via in-pipe injection upstream of the Ag/Al2O3 catalyst with the engine operating under lean conditions. A number of engine conditions were chosen to provide a range of temperatures and space velocities for evaluation of catalyst performance.
2015-04-14
Technical Paper
2015-01-1009
Cameron W. Tanner, Kenneth Twiggs, Tinghong Tao, David Bronfenbrenner, Yoshiaki Matsuzono, Shinichiro Otsuka, Yukio Suehiro, Hiroshi Koyama
Abstract Regulations that limit emissions of pollutants from gasoline-powered cars and trucks continue to tighten. More than 75% of emissions through an FTP-75 regulatory test are released in the first few seconds after cold-start. A factor that controls the time to catalytic light-off is the heat capacity of the catalytic converter substrate. Historically, substrates with thinner walls and lower heat capacity have been developed to improve cold-start performance. Another approach is to increase porosity of the substrate. A new material and process technology has been developed to significantly raise the porosity of thin wall substrates (2-3 mil) from 27-35% to 55% while maintaining strength. The heat capacity of the material is 30-38% lower than existing substrates. The reduction in substrate heat capacity enables faster thermal response and lower tailpipe emissions. The reliance on costly precious metals in the washcoat is demonstrated to be lessened.
2015-04-14
Technical Paper
2015-01-1010
Hongsuk Kim, Hoyeol Lee, Sunyoup Lee, Gyubaek Cho
Diesel burners have been used to regenerate diesel particulate filters (DPF) because of their simplicity in engine torque control and less oil dilution by fuel compared with the commonly used in-cylinder post fuel injection method. We previously developed a novel diesel burner using rotating plasma as an ignition source and found it to be effective in DPF regeneration. Here, we carry out in-depth studies on combustion efficiency of this plasma-ignited diesel burner and investigate the effects of influential factors such as plasma power, the amount of fresh air supplied, and O2 concentration in the exhaust gas on combustion characteristics of the burner. The obtained results show that fresh air supplied to the burner plays an important role in ignition and the early stage of combustion, and O2 concentration in the exhaust gas is identified as the most dominant factor for combustion efficiency.
2015-04-14
Technical Paper
2015-01-1068
Rong Yang, Diming Lou, Piqiang Tan, Zhiyuan Hu, Hongjuan Ren
Abstract Previous studies have indicated that longer torque increase time benefits the reduction of emissions during transient process for a diesel engine. However, quantitative conclusions on reduction of emissions and effects on fuel economy have not been made clear so far. The aim of this study was to evaluate the transient process of diesel engine under different torque increase time, and to find the quantitative statement between torque increase time, fuel economy and engine-out emissions. To do this, experiment was carried out on a 7L common rail diesel engine used for commercial vehicles. Three engine speeds (1100r·min−1, 1300r·min−1 and 1500r·min−1) were chosen to represent an engine working range. For each speed, the engine torque is increased within different time (0.5s, 1s, 2s and 5s). It was shown that, in the transient process mentioned above, engine torque increase time effects fuel economy, smoke opacity and CO emission.
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