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Viewing 151 to 180 of 85301
2017-10-08
Technical Paper
2017-01-2263
S. Vedharaj, R Vallinayagam, Yanzhao An, Mohammad Izadi Najafabadi, Bart Somers, Junseok Chang, Bengt Johansson
Naphtha boils in the gasoline range of 40°C to 75°C with a RON of 65, showing increased resistance to auto-ignition. It is not possible to use naphtha as a drop in fuel for CI engine and therefore, it is ideal to investigate premixed combustion of naphtha. Previous studies reports the use of naphtha in CI engine under partially premixed combustion (PPC) mode, wherein the fuel injection timing and intake air temperature controls combustion. In this study, we investigate the combustion visualization and stratification of surrogate fuel in PPC mode. The composition of naphtha surrogate is 2-methyl butane (0.21% mol), 2-methyl hexane (0.07% mol), n-pentane (0.6% mol), n-heptane (0.07% mol) and toluene (0.05% mol). Investigation of surrogate fuel in engine expands on the previous studies on surrogate fuel formation for naphtha. Based on the experimental outcome, start of injection (SOI) was found to be inversely correlated with combustion phasing during early injection timings.
2017-10-08
Technical Paper
2017-01-2262
Changle Li, Per Tunestal, Martin Tuner, Bengt Johansson
In a former research, the sensitivity of combustion phasing to intake temperature and injection timing during the transition from HCCI to PPC were investigated, fueling with generic gasoline. While digging into the results, special interest was drawn into the relationship between the intake temperature and combustion phasing since it was believed that it properly revealed the changing of stratification level with the injection timing. To confirm its applicability on different fuels also investigate the effect of fuel properties on the formation of stratification, primary reference fuels (PRF) was tested with the same method: a start of injection sweep from -180° to -20° aTDC (after top dead center) with the combustion phasing kept constant by tuning the intake temperature. The results were compared with the former results of gasoline, and the previous conclusions were further developed. A three-stage fuel-air stratification development process, from HCCI to PPC, was observed.
2017-10-08
Technical Paper
2017-01-2261
Xinyan Wang, Hua Zhao
The spark ignition (SI) – controlled auto-ignition (CAI) hybrid combustion, also known as spark-assisted compression ignition (SACI), is achieved by utilizing the temperature and pressure rise from the early flame propagation induced by the spark-ignition to trigger the auto-ignition of the remaining unburned mixture. This hybrid combustion concept can be used to effectively extend the operating range of gasoline CAI combustion and achieve smooth transitions between SI and CAI combustion mode in gasoline engines. However, the significant cycle-to-cycle variation (CCV) of the SI-CAI hybrid combustion hinders the practical application of the hybrid combustion. In order to understand the cause of its high CCVs, the SI-CAI hybrid combustion process in a gasoline engine was studied in this study by the large eddy simulations (LES). The turbulence is modelled by the sub-grid k model. The spark ignition and subsequent flame propagation were modelled by the ECFM-3Z LES model.
2017-10-08
Technical Paper
2017-01-2265
Hao-ye Liu, Zhi Wang, Bowen Li, Shi-Jin Shuai, Jian-Xin Wang
Wide Distillation Fuel (WDF) refers to the fuels with a distillation range from initial boiling point of gasoline to final boiling point of diesel. Recent experimental results have shown WDF by blending 50% gasoline and 50% diesel (G50) exhibits much lower soot emissions than diesel at medium load with relatively low injection ratio with similar thermal efficiency. However, the engine performances fueled by G50 at both low load end and high load end are still unknown. In this study, the combustion and emission characteristics of G50 and diesel have been compared at 1600 r/min and a wide load range from 0.2 MPa IMEP to 1.4 MPa IMEP at a light-duty diesel engine. The results shown that G50 has much lower soot emissions and similar thermal efficiency compared with diesel at high load end. At 0.2 MPa IMEP, G50 exhibits high cycle-to-cycle variation and low thermal efficiency.
2017-10-08
Technical Paper
2017-01-2266
Bin Yang, Hu Wang, Mingfa Yao, Zunqing Zheng, Jialin Liu, Naifeng Ma, Qiping Wang, Haien Zha, Peng Chen
Gasoline partially premixed combustion shows the potential to achieve clean and high efficiency combustion. Injection strategies show significant influence on in-cylinder air flow and in-cylinder concentration distribution before auto-ignition, which can significantly affect the combustion characteristics and emissions. This study explored the effects of various injection strategies, including port fuel injection (PFI), single direct injection (DI), double direct injection (DIP+DIM) and port fuel injection coupled with a direct injection (PFI+DIM) on the combustion characteristics and emissions on a modified single cylinder heavy duty diesel engine fueled with 92# gasoline. The results showed that CA5 and CA50 of DIP+DIM are more sensitive to injection timing than PFI+DIM and single direct injection strategy, partially due to the effects of DIP on mixture stratification and low temperature reaction of gasoline.
2017-10-08
Technical Paper
2017-01-2267
Erik Svensson, Lianhao Yin, Per Tunestal, Martin Tuner
The concept of Partially Premixed Combustion (PPC) in engines has shown to achieve very high gross indicated efficiencies, but at the expense of gas exchange efficiencies. Most of the experimental research on PPC has been conducted on compression ignition engines designed to operate on diesel fuel and relatively high exhaust temperatures. The PPC concept on the other hand relies on dilution with high exhaust gas recirculation (EGR) rates to slow down the combustion which results in low exhaust temperatures, but also high mass flows over cylinder, valves, ports and manifolds. A careful design of the gas exchange system, EGR and charge air coolers is therefore of utter importance. Experiments were performed on a heavy-duty, compression ignition engine using a fuel consisting of 80 percent 89 RON gasoline and 20 percent n-heptane. A wide range of engine speeds and loads were run using a long route EGR system.
2017-10-08
Technical Paper
2017-01-2268
Zhanming Chen, Long Wang, Tiancong Zhang, Qimeng Duan, Bo Yang
Liquefied natural gas (LNG) fuelled engines have been widely equipped on heavy duty vehicles both for fuel-economic and environmental protection concerns, however, they always suffer from deteriorated combustion performance and flame stability due to relatively low burning velocity of methane for lean mixture. In this paper, experimental study was conducted on a turbo-charged, spark-ignition, lean-burn LNG engine with methanol port injection. The combustion characteristics such as cylinder pressure traces, heat release rate (HRR), mass fraction burned (MFB), ignition delay, centroid of heat release, position of CA50 and CA90, as well as cyclic variation of peak pressure were analysed under light load (BMEP=0.3876MPa) with different methanol substitution rates (MSR=0%, 5.2%, 10.2%, 17.2%). The experimental results show that combustion phase advanced with increment of MSR due to faster burning velocity of methanol.
2017-10-08
Technical Paper
2017-01-2334
Chrysovalanti E. Tsesmeli, George S. Dodos, Fanourios Zannikos
Biodiesel (Fatty Acid Methyl Esters) is found to be more prone to oxidative deterioration compared to conventional diesel fuel. In order to guarantee the fuel storage stability, the introduction of antioxidant agents is usually necessary. On the other hand, biodiesel is also associated with microbial growth issues due to its hygroscopic characteristics and its chemical composition leading to fuel bio-deterioration. The aim of this study is to investigate the effect of a variety of phenolic type antioxidant additives on biodiesel and diesel/ biodiesel microbial stability. Five synthetic phenolic type antioxidant agents were added in FAME at concentrations up to 1000 ppm. Treated FAME was also blended with Ultra Low Sulphur Diesel (ULSD) fuel at a concentration of 7% v/v in order to examine the activity of the substances in the final blends.
2017-10-08
Journal Article
2017-01-2345
Ashutosh Gupta, Rachel Seeley, Huifang Shao, Joe Remias, Joseph Roos, Zhi Wang, Yunliang Qi
Low Speed Pre-Ignition (LSPI), also referred to as Superknock or Megaknock is an undesirable turbocharged engine combustion phenomenon limiting fuel economy, drivability, emissions and durability performance. Numerous researchers have previously reported that the frequency of Superknock is sensitive to engine oil and fuel composition as well as engine conditions in controlled laboratory and engine-based studies. Recent studies by Toyota and Tsinghua University have demonstrated that controlled induction of particles into the combustion chamber can induce preignition and superknock. Afton and Tsinghua recently developed a multi-physics approach which was able to realistically model all of the elementary processes known to be involved in deposit induced pre-ignition. The approach was able to successfully simulate deposit induced pre-ignition at conditions where the phenomenon has been experimentally observed.
2017-10-08
Technical Paper
2017-01-2275
Chen Yang, Weixin li, Jiandong Yin, Yuan Shen
Abstract: In order to meet increasingly stringent emission regulations and reduce fuel consumption, development of modern powertrain is becoming more complicated, combining many advanced technologies. Gasoline engine downsizing is already established as a proven technology to reduce vehicle fleet CO2 emissions. Compressed natural gas (CNG) offers increased potential to further reduce both tailpipe CO2 and other regulated exhaust gas emissions without compromising driving performance. In this study, a turbocharged CNG port fuel injection (PFI) engine was developed based on gasoline version. Making most use of positive fuel properties of CNG, the paper quantifies the performance characteristics of downsized CNG engine considering reduced knock sensitivity, adaption of compression ratio and combustion efficiency. While peak cylinder pressure was controlled below 120bar, peak torque 180Nm, same level as gasoline variant, was realized from 3000rpm.
2017-10-08
Technical Paper
2017-01-2277
Xiao Peng, Han Wu, Chia-Fon Lee, Qianbo Sun, Fushui Liu
Methanol has been regarded as a potential transportation fuel due to its advanced combustion characteristics and flexible source. However, it is suffering from misfire and high HC emissions problems under cold start and low load conditions either on methanol SI engine or on methanol/diesel dual fuel engine. Hydrogen is a potential addition that can enhance the combustion of methanol due to its high flammability and combustion stability. In the current work, the effect of hydrogen fraction on the laminar flame characteristics of methanol- hydrogen-air mixture under varied equivalence ratio was investigated on a constant volume combustion chamber system coupled with a schlieren setup. Experiments were performed over a wide range of equivalence ratio of the premixed charge, varied from 0.8 to 1.4, as well as different hydrogen fraction, 0%, 5%, 10%, 15% and 20% (n/n). All tests were carried out at fixed temperature and pressure of 400K and 0.1MPa.
2017-10-08
Technical Paper
2017-01-2280
Yuzuru Nada, So Morimoto, Yoshiyuki Kidoguchi, Ryu Kaya, Hideaki Nakano, Shinichi Kobayashi
In our previous studies, we have developed natural gas engines operating under lean conditions to improve thermal efficiency and emission characteristics. We applied a sub-chamber injection system to our engines, in which natural gas is directly injected into a combustion sub-chamber in order to completely separate stoichiometric mixture in the sub-chamber from ultra-lean mixture in the main chamber. The results obtained from engine tests demonstrated excellent performance of our engines in view point of efficiency and NOx emissions. However, we have poor knowledge of mixture distributions in the combustion chambers to understand the mechanism of the improvements. The aim of this paper is to clarify the mixture formation in combustion chambers by means of numerical simulations in the combustion chamber with and without the sub-chamber at a variety of operating conditions.
2017-10-08
Technical Paper
2017-01-2270
Fushui Liu, Yue Kang, Han Wu, Chia-Fon Lee, Yikai Li
CNG-diesel dual fuel combustion mode has been regarded as a practical engine operation strategy because it not only can remain the high thermal efficiency of diesel engine but also can make full use of an alternative fuel—natural gas,which has excellent advantages in economic performance and environmental protection. However, it is suffering from misfire and high HC emissions problems under cold start and low load conditions due to the low combustion speed and high ignition energy of natural gas. As known, hydrogen is a clear energy which has extremely high flammability. Thus, a certain proportion of hydrogen can be added in the natural gas (named HCNG after blending) to improve combustion. In current work, the effect of hydrogen addition on the combustion and flame propagation characteristics of dual fuel engine was studied based on an optical engine by using high speed camera to capture the flame images and Ki-Box to collect the cylinder pressures.
2017-10-08
Technical Paper
2017-01-2278
Zhiwei Deng, Ang Li, Lei Zhu, Zhen Huang
In-cylinder thermochemical fuel reforming (TFR) in spark ignition nature gas engine was developed to reveal that thermochemical fuel reforming could increase H2 and CO concentration in reformed gas, leading to an increase of thermal efficiency and engine performance. Moreover, ethanol enrichment has been proved to have great potential to optimize TFR performance. In order to explain TFR phenomenon chemically, methane oxidation experiments were conducted in a laminar flow reactor with addition of ethanol and methanol at equivalent ratios of 1.5, 1.7, 1.9 and 2.1 from 948K to 1098K at atmospheric pressure. Experimental results showed that methanol have great ability to facilitate the oxidation of methane than that of ethanol. Meanwhile, the degree of methane conversion became more significantly as the equivalent ratio increased. Kinetic analysis of oxidation of methane with alcohol enrichment in a plug flow model was also conducted in this study.
2017-10-08
Technical Paper
2017-01-2269
Shijun Dong, Xiaobei Cheng, Biao Ou, Can Yang, Zhaowen Wang, Fumin Pan
Abstract: A reduced n-heptane/iso-octane/ethanol/PAH mechanism was proposed and validated with various experimental data. Based on this mechanism, simulations were carried out to investigate the combustion characteristics of n-heptane spray under premixed ethanol/air and iso-octane/air atmosphere. The effects of premixed ethanol and iso-octane on ignition delay, important soot precursors and soot volume fraction of n-heptane spray under different ambient temperatures were studied. And the simulated results with and without considering the cooling effects of premixed fuel vaporization were compared. When the cooling effect of premixed fuel vaporization was not considered, the simulation results showed that the premixed ethanol could increase the ignition delay of n-heptane spray for ambient temperature below 850K, while the inhibition effect of ethanol on ignition disappeared when the ambient temperature was further increased.
2017-10-08
Technical Paper
2017-01-2271
Zhongshu Wang, Mingyang Shao, Ming Li, Dan Wang, Zhongchang Liu
For diesel/natural gas dual fuel engine, the combustion of pilot diesel plays an important role to the following mixture combustion process. To better understand the effects of multiple injections, a detailed study was conducted on a 6-cylinder turbocharged intercooler diesel/natural gas dual fuel heavy-duty engine at low to mid-range loads. Multiple variables were tested, including single injection timings, multiple injections timings and mass ratios, natural gas percentage of energy substitution, engine speeds and loads. The investigated results show that pilot diesel multiple injections have an obviously effect on not only pilot diesel combustion process but also natural gas mixture combustion process. Early injection leads to pilot diesel ignition mode differs from traditional diesel engine compression ignition mode in the sense that it does not occur at a specific place in the spray, which is a two-stage auto ignition mode.
2017-10-08
Technical Paper
2017-01-2273
Xiaokun Nie, Wanhua Su
A numerical simulation was performed to investigate the pilot ignited natural gas combustion process in a direct injection natural gas engine. Various mixture distribution characteristics were compared in terms of the evolution of mixture equivalent ratio distributions and mixture concentration stratifications around top dead center (TDC). Based on above, the pilot injections were specially designed to investigate ignition core formation and its effects on natural gas combustion process. The result shows that pilot ignition sites have great impacts on pilot fuel ignition process and natural gas combustion process. The pilot ignition site on the region with rich NG/Air mixture is disadvantageous to the pilot fuel ignition due to a lack of oxygen, which is not beneficial to ignition core formation.
2017-10-08
Journal Article
2017-01-2296
Andreas Glawar, Fabian Volkmer, Yanyun Wu, Adrian Groves
Driven by increasingly stringent tailpipe CO2 and fuel economy regulations, gasoline direct injection (GDI) engines are enjoying rapidly increasing market penetration. Already more than 50% of newly produced vehicles in the US and western Europe feature direct-injection technology and markets in Asia are catching up quickly. However, with the adoption of this new GDI engine technology, which is able to push the boundaries of engine efficiency, new challenges are starting to arise such deposits which can adversely affect performance. Multi-hole solenoid actuated fuel injectors are particular vulnerable to deposits left by some market fuels. In order to address this challenge, the development of a reliable test platform for injector cleanliness in GDI engines is currently underway in both the US and Europe.
2017-10-08
Technical Paper
2017-01-2292
George S. Dodos, Florentia Vassileiou, Dimitrios Karonis
Lubricity is considered as one of the fundamental quality parameters of diesel fuel since several diesel engine parts, such as pumps and injectors, are lubricated by the fuel itself. The dramatic reduction of sulfur content in diesel fuel leads to the elimination of heterocyclic compounds that are beneficial to lubricity. As a result especially in ultra low sulfur diesel the lubricating efficiency has to be fulfilled by the contained hydrocarbons. Therefore, it is very interesting to know to what extend each type of hydrocarbon contributes to diesel fuel lubricity when neither FAME nor a lubricity improver is employed. The aim of this study is to investigate the lubricity of hydrocarbons that constitute components of petroleum diesel fuel. A number of typical hydrocarbon compounds were selected as representatives of the group types of paraffins, olefins, cycloparaffins and aromatics, similar to those that are present in diesel fuel.
2017-10-08
Journal Article
2017-01-2291
Sandro Gail, Takashi Nomura, Hitoshi Hayashi, Yuichiro Miura, Katsumi Yoshida, Vinod Natarajan
In emerging markets, Port Fuel Injection (PFI) technology retains a higher market share than Gasoline Direct Injection (GDI) technology. In these markets fuel quality remains a concern even despite an overall improvement in quality. Typical PFI engines are sensitive to fuel quality regardless of brand, engine architecture, or cylinder configuration. One of the well-known impacts of fuel quality on PFI engines is the formation of Intake Valve Deposits (IVD). These deposits steadily accumulate over time and can lead to a deterioration of engine performance. IVD formation mechanisms have been characterized in previous studies. However, no test is available on a state-of-the-art engine to study the impact of fuel components on IVD formation. Therefore, a proprietary engine test was developed to test several chemistries. Sixteen fuel blends were tested. The deposit formation mechanism has been studied and analysed.
2017-10-08
Technical Paper
2017-01-2287
Aniseh Abdalla, Guoyang Wang, Jun Zhang, Shi-Jin Shuai
Emission control technologies are required to achieve stringent emission regulations such as Beijing 6 (equivalent to Europe 6). In order to meet Europe 6 emission regulation, diesel oxidation catalyst (DOC) upstream of catalyzed diesel particulate filter (CDPF) with supplementary fuel injection (hydrocarbon injection (HCI)) are used for the X7 diesel engine to control the particulate matter (PM) for a heavy-duty diesel engine. This study investigated soot loading and active regeneration process in a CDPF by using secondary fuel injection in order to enhance exothermal heat which is needed to raise the CDPF temperature. The injected fuel is burnt in a DOC where the injector is mounted in the tailpipe upstream of DOC.
2017-10-08
Technical Paper
2017-01-2281
Lang Jiang, Zhe Kang, Zhehao Zhang, Zhijun Wu, Jun Deng, Zongjie Hu, Liguang Li
It is a widely consensus that the ambient temperature direct water injection can be utilized to reduce nitric oxides emissions in both diesel and gasoline engine. Since the proposal of water injection technology, there are many researches studying the effect of different direct water injection strategies on nitric oxides emissions and engine performance which generally lead to lower nitric oxides emissions while combustion efficiency deteriorated. The present work aimed at optimizing diesel engine combustion efficiency with the decrement of nitric oxides emissions using optimized water injection strategy. The engine has been modified based on a two cylinder mechanical pump diesel engine into common rail diesel engine with capability in direct water injection. The direct water injection system is designed and manufactured independently, an air-fluid booster is utilized to establish the water injection pressure up to 40MPa.
2017-10-08
Technical Paper
2017-01-2325
Midhat Talibi, Paul Hellier, Nicos Ladommatos
The conversion of lignocellulosic biomass to liquid fuels presents an alternative to the current production of renewable fuels for IC engines from food crops. However, realising the potential for reductions in net CO2 emissions through the utilisation of, for example, waste biomass for sustainable fuel production requires that energy and resource inputs into such processes be minimised. This work therefore investigates the combustion and emission characteristics of five intermediate platform molecules potentially derived from lignocellulosic biomass: gamma-valerolactone (GVL), methyl valerate, furfuryl alcohol, furfural and 2-methyltetrahydrofuran (MTHF). The study was conducted on a naturally aspirated, water cooled, single cylinder spark-ignition engine. Each of the platform molecules were blended with reference fossil gasoline at 20 % wt/wt.
2017-10-08
Technical Paper
2017-01-2321
Timothy H. Lee, Han Wu, Alan Hansen, Tonghun Lee, Gang Li
Bio-butanol has been considered as a promising alternative fuel for transportation due to its advantageous physical and chemical properties, but the high recovery and dehydration cost reduced its competitiveness in the fuel market. In order to achieve the bio-fuel advantage, the current work tried to apply and evaluate the upstream products of bio-butanol, Isopropanol-Butanol-Ethanol (IBE). These mixtures are obtained by ABE fermentation and IBE fermentation respectively, as alternative diesel fuel. Isopropanol-Butanol-Ethanol (IBE) is an intermediate product in the IBE fermentation process for producing bio-butanol. The study was carried out in an AVL 5402 single-cylinder diesel engine fueled by IBE-Diesel, ABE-Diesel and neat diesel. During the experiments, the engine speed, engine loads, and injection timings were varied. The results showed that with the addition of IBE in diesel fuel, the engine can still operate smoothly with a set pilot injection.
2017-10-08
Technical Paper
2017-01-2313
Zenghui Yin, Xiaojun Jing, Tieqiang Fu, Hua Zhou, Chunde Yao, Jiangtao Hu, Peilin Geng
In-cylinder direct-injected technology provides a flexible and accurate optimization solution for internal combustion engines to reduce emissions and improve fuel efficiency. With increasingly stringent requirements for nitrogen oxides (NOx) and CO2 emissions, the number of injections in a engine combustion cycle has reached 2 to 3 times in gasoline direct injection (GDI) and high pressure common rail (HPCR) diesel engine. Accurate control of both the timing and quantity of injection events is critical for engine performance and emissions, while the dynamic response of the injector spray characteristic is the key factor. In this paper, a test bench was built for monitoring solenoid injector’s dynamic response, using high-speed microphotography and synchronous current collection system. Experimental study on the dynamic response of GDI and HPCR solenoid injectors was carried out.
2017-10-08
Technical Paper
2017-01-2297
Thomas Dubois, Lidwine Abiad, Pauline Caine
As it is the case for Diesel engines, the Gasoline Direct Injection engines are using higher and higher injection pressures. The state of the art GDI engines are currently using injection pressure as high as 500 bar. A lot of work is also currently ongoing on Gasoline Compression Ignition (GCI) engines which use even higher injection pressure (above 1 000 bar). A high injection pressure means that a high pressure pump has to be used and so, proper lubricity has to be brought by the fuel. In the mean time the use of biofuels is increasing and several studies have shown the positive impact of ethanol on the fuel consumption of gasoline engines mainly thru an octane number effect. For all these reasons, it seems important to evaluate the impact of ethanol on the lubricity of gasoline as well as on the response of lubricity additives that may be required in a medium-term future to provide gasoline enough lubricity to ensure the operability of these new engines.
2017-10-08
Journal Article
2017-01-2285
Eric Randolph, Raphael Gukelberger, Terrence Alger, Thomas Briggs, Christopher Chadwell, Antonio Bosquez Jr.
Abstract The primary focus of this investigation was to determine the hydrogen reformation, efficiency and knock mitigation benefits of methanol-fueled Dedicated EGR (D-EGR®) operation, when compared to other EGR types. A 2.0 L turbocharged port fuel injected engine was operated with internal EGR, high-pressure loop (HPL) EGR and D-EGR configurations. The internal, HPL-EGR, and D-EGR configurations were operated on neat methanol to demonstrate the relative benefit of D-EGR over other EGR types. The D-EGR configuration was also tested on high octane gasoline to highlight the differences to methanol. An additional sub-task of the work was to investigate the combustion response of these configurations. Methanol did not increase its H2 yield for a given D-EGR cylinder equivalence ratio, even though the H:C ratio of methanol is over twice typical gasoline.
2017-10-08
Journal Article
2017-01-2295
Ahmad Omari, Stefan Pischinger, Om Parkash Bhardwaj, Bastian Holderbaum, Jukka Nuottimäki, Markku Honkanen
Abstract The optimization study presented herein is aimed to minimize the fuel consumption and engine-out emissions using commercially available EN15940 compatible HVO (Hydrogenated Vegetable Oil) fuel. The investigations were carried out on FEV’s 3rd generation HECS (High Efficiency Combustion System) multi-cylinder engine (1.6L, 4 Cylinder, Euro 6). Using a global DOE approach, the effects of calibration parameters on efficiency and emissions were obtained and analyzed. This was followed by a global optimization procedure to obtain a dedicated calibration for HVO. The study was aiming for efficiency improvement and it was found that at lower loads, higher fractions of low pressure EGR in combination with lower fuel injection pressures were favorable. At higher loads, a combustion center advancement, increase of injection pressure and reduced pilot injection quantities were possible without exceeding the noise and NOx levels of the baseline Diesel.
2017-10-08
Journal Article
2017-01-2293
Jim Barker, Jacqueline Reid, Sarah Angel Smith, Colin Snape, David Scurr, Graham Langley, Krina Patel, Anastarsia Carter, Cris Lapthorn, Frank Pullen
Abstract Studies of diesel system deposits continue to be the subject of interest and publications worldwide. The introduction of high pressure common rail systems resulting in high fuel temperatures in the system with the concomitant use of fuels of varying solubilizing ability (e.g. ULSD and FAME blends) have seen deposits formed at the tip of the injector and on various internal injector components. Though deposit control additives (DCAs) have been successfully deployed to mitigate the deposit formation, work is still required to understand the nature and composition of these deposits. The study of both tip and internal diesel injector deposits (IDID) has seen the development of a number of bench techniques in an attempt to mimic field injector deposits in the laboratory. One of the most used of these is the Jet Fuel Thermal Oxidation Tester or JFTOT (ASTM D3241).
2017-10-08
Journal Article
2017-01-2298
Charles S. Shanahan, S. Scott Smith, Brian D. Sears
Abstract The ubiquity of gasoline direct injection (GDI) vehicles has been rapidly increasing across the globe due to the increasing demand for fuel efficient vehicles. GDI technology offers many advantages over conventional port fuel injection (PFI) engines, such as improvements in fuel economy and higher engine power density; however, GDI technology presents unique challenges as well. GDI engines can be more susceptible to fuel injector deposits and have higher particulate emissions relative to PFI engines due to the placement of the injector inside the combustion chamber. Thus, the need for reliable test protocols to develop next generation additives to improve GDI vehicle performance is paramount. This work discloses a general test method for consistently fouling injectors in GDI vehicles and engines that can accommodate multiple vehicle/engine types, injector designs, and drive cycles, which allows for development of effective GDI fuel additives.
Viewing 151 to 180 of 85301