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2015-04-14
Technical Paper
2015-01-1032
Z. Gerald Liu, Nathan Ottinger
U.S. and European nonroad diesel emissions regulations have led to the implementation of various exhaust aftertreatment solutions. One approved configuration, a vanadium-based selective catalytic reduction catalyst followed by an ammonia oxidation catalyst (V-SCR + AMOX), does not require the use of a diesel oxidation catalyst (DOC) or diesel particulate filter (DPF). While certification testing has shown the V-SCR + AMOX system to be capable of meeting the nitrogen oxides, carbon monoxide, and particulate matter requirements, open questions remain regarding the efficacy of this aftertreatment for volatile and nonvolatile organic emissions removal, especially since the removal of this class of compounds is generally attributed to both the DOC and DPF.
2015-04-14
Technical Paper
2015-01-1684
KV Shivaprasad, PR Chitragar, GN Kumar
Fast depletion of fossil fuels and their detrimental effect to the environment is demanding an urgent need of alternative fuels for meeting sustainable energy demand with minimum environmental impact. A lot of research is being carried throughout the world to evaluate the performance, exhaust emission and combustion characteristics of the existing engines using several alternative fuels. Expert studies indicate hydrogen is one of the most promising energy carriers for the future due to its superior combustion qualities and availability. This article experimentally characterizing the combustion and emission parameters of a single cylinder high speed SI engine operating with different concentrations of hydrogen with gasoline fuel. For this purpose, the conventional carbureted high speed SI engine was modified into an electronically controllable engine, wherein ECU was used to control the injection timings and durations of gasoline.
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
2015-01-0343
Carlo N. Grimaldi, Claudio Poggiani, Alessandro Cimarello, Matteo De Cesare, Giovanni Osbat
Abstract The emissions limits of CO2 for vehicles are becoming more stringent with the aim of reducing greenhouse gas emissions and improve fuel economy. The New European Driving Cycle (NEDC) is adopted to measure emissions for all new internal combustion engines in the European Union, and it is performed on cold vehicle, starting at a temperature of 22°C ± 2°C. Consequently, the cold-start efficiency of internal combustion engine is becoming of predominant interest. Since at cold start the lubricant oil viscosity is higher than at the target operating temperature, the consequently higher energy losses due to increased frictions can substantially affect the emission cycle results in terms of fuel consumption and CO2 emissions. A suitable thermal management system, such as an exhaust-to-oil heat exchanger, could help to raise the oil temperature more quickly.
2015-04-14
Technical Paper
2015-01-1007
Steve Golden, Zahra Nazarpoor, Maxime Launois
Abstract In the context of evolving market conditions the Three-Way Catalyst (TWC) is entering an exciting new phase. It remains the main emission control strategy for gasoline powered vehicles but a period of rapidly evolving engine development, tighter tailpipe regulations and material supply issues present a unique challenge to catalyst developers. This paper presents an initial study outlining the development of spinel mixed metal oxides for application in modern TWC and addresses some specific challenges underlying this application. Lab and flow reactor data in the study showed how the spinel structure has significant potential in various aspects of the TWC with the necessary improvement in thermal stability. Some initial engine data show three-way performance at or near stoichiometric in a PGM and rare earth free spinel coating and a synergy effect when combined with PGM.
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
2015-01-1000
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
2015-01-1003
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
Technical Paper
2015-01-0997
Jonas Jansson, Åsa Johansson, Hanna Sjovall, Mikael Larsson, Gudmund Smedler, Colin Newman, Jason Pless
Abstract This paper will review several different emission control systems for heavy duty diesel (HDD) applications aimed at future legislations. The focus will be on the (DOC+CSF+SCR+ASC) configuration. As of today, various SCR technologies are used on commercial vehicles around the globe. Moving beyond EuroVI/US10 emission levels, both fuel consumption savings and higher catalyst system efficiency are required. Therefore, significant system optimization has to be considered. Examples of this include: catalyst development, optimized thermal management, advanced urea dosing calibrations, and optimized SCR inlet NO:NO2 ratios. The aim of this paper is to provide a thorough system screening using a range of advanced SCR technologies, where the pros and cons from a system perspective will be discussed. Further optimization of selected systems will also be reviewed. The results suggest that current legislation requirements can be met for all SCR catalysts under investigation.
2015-04-14
Technical Paper
2015-01-0742
Apostolos Karvountzis-Kontakiotis, Leonidas Ntziachristos, Zissis Samaras, Athanasios Dimaratos, Mark Peckham
Abstract Cyclic combustion variability (CCV) is an undesirable characteristic of spark ignition (SI) engines, and originates from variations in gas motion and turbulence, as well as from differences in mixture composition and homogeneity in each cycle. In this work, the cycle to cycle variability on combustion and emissions is experimentally investigated on a high-speed, port fuel injected, spark ignition engine. Fast response analyzers were placed at the exhaust manifold, directly downstream of the exhaust valve of one cylinder, for the determination of the cycle-resolved carbon monoxide (CO) and nitric oxide (NO) emissions. A piezoelectric transducer, integrated in the spark-plug, was also used for cylinder pressure measurement. The impact of engine operating parameters, namely engine speed, load, equivalence ratio and ignition timing on combustion and emissions variability, was evaluated.
2015-04-14
Technical Paper
2015-01-0752
Zhi Wang, Yunliang Qi, Hui Liu, Yan Long, Jian-Xin Wang
Abstract Occurrence of sporadic super-knock is the main obstacle to the development of advanced gasoline engines. One of the possible inducements of super-knock, agglomerated soot particle induced pre-ignition, was studied for high boosted gasoline direct injection (GDI) engines. The correlation between soot emissions and super-knock frequency was investigated in a four-cylinder gasoline direct injection production engine. The test results indicate that higher in-cylinder soot emission correlate with more pre-ignition and super-knock cycles in a GDI production engine. To study the soot/carbon particles trigger super-knock, a single-cylinder research engine for super-knock study was developed. The carbon particles with different temperatures and sizes were introduced into the combustion chamber to trigger pre-ignition and super-knock.
2015-04-14
Technical Paper
2015-01-0755
Yasuo Moriyoshi, Toshio Yamada, Daisuke Tsunoda, Mingzhao Xie, Tatsuya Kuboyama, Koji Morikawa
Abstract The authors investigated the reasons of how a preignition occurs in a highly boosted gasoline engine. Based on the authors' experimental results, theoretical investigations on the processes of how a particle of oil or solid comes out into the cylinder and how a preignition occurs from the particle. As a result, many factors, such as the in-cylinder temperature, the pressure, the equivalence ratio and the component of additives in the lubricating oil were found to affect the processes. Especially, CaCO3 included in an oil as an additive may be changed to CaO by heating during the expansion and exhaust strokes. Thereafter, CaO will be converted into CaCO3 again by absorbing CO2 during the intake and compression strokes. As this change is an exothermic reaction, the temperature of CaCO3 particle increases over 1000K of the chemical equilibrium temperature determined by the CO2 partial pressure.
2015-04-14
Technical Paper
2015-01-0873
Bin Mao, Mingfa Yao, Zunqing Zheng, Yongzhi Li, Haifeng Liu, Bowen Yan
Abstract An experimental study is carried out to compare the effects of high-pressure-loop, low-pressure-loop and dual-loop exhaust gas recirculation systems (HPL-EGR, LPL-EGR and DL-EGR) on the combustion characteristics, thermal efficiency and emissions of a diesel engine. The tests are conducted on a six-cylinder turbocharged heavy-duty diesel engine under various operating conditions. The low-pressure-loop portion (LPL-Portion) of DL-EGR is swept from 0% to 100% at several constant EGR rates, and the DL-EGR is optimized based on fuel efficiency. The results show that the LPL-EGR can attain the highest gross indicated thermal efficiency (ITEg) in the three EGR systems under all the tested conditions. At a middle load of 0.95 BMEP, 1660 r/min, the pumping losses of LPL-EGR lead to the lowest BTE among the EGR systems. The HPL-EGR can achieve the best brake thermal efficiency (BTE) and emissions within the EGR rate of 22.5% mainly due to the reduced pumping losses.
2015-04-14
Technical Paper
2015-01-0990
Brett M. Bailey
This paper details the development of Cool Particulate Regeneration™, CPR™, an ultra-efficient non-thermal active particulate filter regeneration technology for gasoline and diesel particulate filters. In the technologies simplest form, mechanical two-way regeneration valves are sequentially and in rapid succession pneumatically actuated to induce a reverse flow filter cleaning. Their operation generates exhaust pressure by sealing off the exhaust system preventing filtered engine exhaust from exiting the tailpipe. The filtered and pressurized gases are then released to a separate low pressure particulate matter (PM) reservoir upstream of the filter. The reverse flow of high pressure filtered exhaust gases pass back though the filter physically dislodging the particulate and transporting it to the low pressure storage chamber. Innovative utilization of the particulate matter is discussed. CPR has undergone bench testing and two generations of research and development.
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
2015-01-1015
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
2015-01-1221
Jamie Knapp, Adam Chapman, Sagar Mody, Thomas Steffen
Hybrid electric vehicles offer significant fuel economy benefits, because battery and fuel can be used as complementing energy sources. This paper presents the use of dynamic programming to find the optimal blend of power sources, leading to the lowest fuel consumption and the lowest level of harmful emissions. It is found that the optimal engine behavior differs substantially to an on-line adaptive control system previously designed for the Lotus Evora 414E. When analyzing the trade-off between emission and fuel consumption, CO and HC emissions show a traditional Pareto curve, whereas NOx emissions show a near linear relationship with a high penalty. These global optimization results are not directly applicable for online control, because they require knowledge of the whole drive cycle in advance, but they can guide the design of a more efficient hybrid control system.
2015-04-14
Technical Paper
2015-01-0999
Jan Schoenhaber, Joerg Michael Richter, Joel Despres, Marcus Schmidt, Stephanie Spiess, Martin Roesch
Abstract The new emission regulations in Europe, EU 6 will promulgate more realistic driving conditions with more stringent HC, CO, NOx and particulate emissions. This legislation will also include the WLTP (Worldwide harmonized Light vehicles Test Procedure) cycle for CO2 measurements and a new requirement called “Real-Driving-Emissions” (RDE) as well. The RDE requirement is to ensure modern vehicles comply with the legislation under all conditions of normal driving. More robust aftertreatment solutions are needed to meet these new requirements. This work introduces an improved three-way catalyst (TWC) for gasoline engines for these new regulations. It is tested under static and dynamic conditions and on several engines and vehicles with various drive cycles. It offers better thermal stability combined with lower backpressure than former TWC generations.
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
Technical Paper
2015-01-0772
Ashish J. Chaudhari, Vinayak Kulkarni, Niranjan Sahoo
Abstract In this study, the effect of using higher research octane rating fuel Liquefied Petroleum Gas (LPG) in respect of gasoline in the spark ignition engine on the performance and exhaust emission was experimentally studied. For this purpose, the tilting block technique of varying the compression ratio from 8 to 10 of the engine has been implemented and attention has been paid towards the variation of performance and combustion parameters with LPG fuel. Most undesirable emissions are exhausted by the spark ignition (SI) engines in which the primary pollutants from the engine (such as NOx) which when mixed in the atmosphere react with ozone and create the secondary pollutant that are more harmful to human health. Looking at this fact, while optimizing the compression ratio, the emission reduction technique like intake charge dilution with exhaust gas from the engine has been studied.
2015-04-14
Technical Paper
2015-01-0776
Gerben Doornbos, Stina Hemdal, Daniel Dahl
Abstract This study investigated how the amount of dilution applied can be extended while maintaining normal engine operation in a GDI engine. Adding exhaust gases or air to a stoichiometric air/fuel mixture yields several advantages regarding fuel consumption and engine out emissions. The aim of this paper is to reduce fuel consumption by means of diluted combustion, an advanced ignition system and adjusted valve timing. Tests were performed on a Volvo four-cylinder engine equipped with a dual coil ignition system. This system made it possible to extend the ignition duration and current. Furthermore, a sweep was performed in valve timing and type of dilution, i.e., air or exhaust gases. While maintaining a CoV in IMEP < 5%, the DCI system was able to extend the maximum lambda value by 0.1 - 0.15. Minimizing valve overlap increased lambda by an additional 0.1.
2015-04-14
Technical Paper
2015-01-0800
Yann Gallo, Johan Simonsson, Ted Lind, Per-Erik Bengtsson, Henrik Bladh, Oivind Andersson
Abstract Two competing in-cylinder processes, soot formation and soot oxidation, govern soot emissions from diesel engines. Previous studies have shown a lack of correlation between the soot formation rate and soot emissions. The current experiment focuses on the correlation between soot oxidation rates and soot emissions. Laser extinction is measured using a red (690nm) laser beam, which is sent vertically through the cylinder. This wavelength is long enough to minimize absorption interference from poly-aromatic hydrocarbons, while still in the visible regime. It is modulated at 72 kHz in order to produce 10 pulses per crank angle degree at an engine speed of 1200 rpm. The intake oxygen concentration is varied between 9% and 21%. The time resolved extinction measurements are used to estimate soot oxidation rates during expansion.
2015-04-14
Technical Paper
2015-01-0383
Changpu Zhao, Gang Yu, Junwei Yang, Man Bai, Fang Shang
Abstract Diesel engines generally tend to produce a very low level of NOx and soot through the application of Miller Cycle, which is mainly due to the low temperature combustion (LTC) atmosphere resulting from the Miller Cycle utilization. A CFD model was established and calibrated against the experimental data for a part load operation at 3000 r/min. A designed set of Miller-LTC combustion modes were analyzed. It is found that a higher boost pressure coupled with EGR can further tap the potential of Miller-LTC cycle, improving and expanding the Miller-LTC operation condition. The simulated results indicated that the variation of Miller timings can decrease the regions of high temperatures and then improve the levels and trade-off relationship of NOx and soot. The in-cylinder peak pressure and NOx emissions were increased dramatically though the problem of insufficient intake charge was resolved by the enhanced intake pressure that is equivalent to dual-stage turbo-charging.
2015-04-14
Technical Paper
2015-01-0836
Behzad Rohani, Stephen Sungsan Park, Choongsik Bae
Abstract Low Temperature Combustion (LTC) is known to be feasible only in lower load ranges so in real world application of LTC, engine operation mode should frequently change back and forth between LTC mode in lower loads and conventional mode in higher loads. In this research, effect of injection strategy on smoothness and emissions during mode transition in a single cylinder heavy duty diesel engine is studied. The Exhaust Gas Recirculation (EGR) line was controlled by a servo-valve capable of opening or closing the EGR loop within only one engine cycle. Ten cycles after the EGR valve closure were taken as the transition period during which injection timing and quantity were shifted in various ways (i.e. injection strategies) and the effect on Indicated Mean Effective Pressure (IMEP) stability and emissions was studied.
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
Technical Paper
2015-01-0903
Neeraj Mittal, Pradeep Patanwal, M Sithananthan, M Subramanian, Ajay Kumar Sehgal, R Suresh, B P Das
Abstract N-butanol is a promising alternative fuel which needs no engine modification when used as a blend with diesel. The miscibility of n-butanol with diesel is excellent in a wide range of blending ratios. N-butanol has high oxygen content and a comparable energy content, specific gravity and viscosity to that of diesel, which makes it attractive for diesel engines as an alternative fuel. An experimental investigation was conducted to assess the performance of a new generation passenger car with respect to power, fuel economy (FE) and mass emission using 5, 10 and 20 percent (by vol.) n-butanol blends with diesel (NB). Computer controlled DC motor driven chassis dynamometer, AVL AMA I60 mass emission measuring system and AVL FSN smoke meter were used for measuring wide open throttle (WOT) power, road load simulation (RLS) fuel economy, mass emissions and smoke in WOT and steady speed driving conditions.
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
2015-01-1008
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
2015-01-1070
Hanzhengnan Yu, Yong Guo, Donghai Li, Xingyu Liang, Ge-Qun Shu, Yuesen Wang, Xiangxiang Wang, Lihui Dong
Abstract Impingement of injected fuel spray against the cylinder liner (wall wetting) is one of the main obstacles that must be overcome in order for early injection Homogeneous Charge Compression Ignition (EI HCCI) combustion. In the strategies to reduce or prevent wall wetting explored in the past, limiting the spray cone angle was proved to be a useful approach. This paper is presented to study the effect of the spray cone angle on the mixture formation, particularly the region near the cylinder wall (wall wetting region), and CO/Soot emissions of an EI HCCI diesel engine. Three-dimensional modeling was performed in AVL FIRE code. The calculation grid was divided into three regions which were defined as the combustion chamber region, the wall wetting region, and the central regions. The history of the CO/soot mass of each region and the equivalent ratio/temperature (φ-T map) of wall wetting region were analyzed.
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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