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Viewing 181 to 210 of 44126
2017-10-08
Technical Paper
2017-01-2288
Tianyuan Zhou, Changsheng Yao, Fuyuan Yang, Sun Jinwei
Abstract Low temperature combustion (LTC) is an advanced combustion mode, which can achieve low emissions of NOx and PM simultaneously, and keep relatively high thermal efficiency at the same time. However, one of the major challenges for LTC is the cold condition. In cold conditions, stable compression ignition is hard to realize, while thermal efficiency and emissions deteriorate, especially for gasoline or fuel with high octane number. This study presents using pressure sensor glow plugs (PSG) to realize Glow plug assisted compression ignition (GA-CI) at cold conditions. Further, a glow plug control unit (GPCU) is developed, a closed-loop power feedback control algorithm is introduced based on GPCU. In the experiment, engine coolant temperature is swept. Experimental results show that GA-CI has earlier combustion phases, larger combustion duration and higher in-cylinder pressure. And misfire is avoided, cycle-to-cycle variations are greatly reduced.
2017-10-08
Technical Paper
2017-01-2379
Qian Feng, Shu Shen, Mengliang Li, Zhijun Li, Kongjian Qin, Diming Lou, Jiguang Wang, Xiyu Fang
Abstract Recent toxicological and epidemiologic studies have shown that diesel emissions have been a significant toxic air contaminant. Catalyzed DPF (CDPF) not only significantly reduces the PM mass emissions (>90%), but also further promotes carrier self-regeneration and oxidize more harmful gaseous pollutants by the catalyst coated on the carrier. However, some ultrafine particles and potentially harmful gaseous pollutants, such as VOCs species, originally emitted in the vapor-phase at high plume temperature, may penetrate through the CDPF filter. Furthermore, the components and content of catalyst coated on the CDPF could influence the physicochemical properties and toxicity intensity of those escaping ultrafine particles and gaseous pollutants. In this work, (1) we investigated the influence of precious metal content as a variable parameter on the physicochemical properties and catalytic activities of the small CDPF samples.
2017-10-08
Journal Article
2017-01-2257
Linjun Yu, Yanfei Li, Bowen Li, Hao-ye Liu, Zhi Wang, Xin He, Shi-jin Shuai
Abstract This study compared the combustion and emission characteristics of Homogeneous Charge Compression Ignition (HCCI) and Direct Injection Compression Ignition (DICI) modes in a boosted and high compression ratio (17) engine fueled with gasoline and gasoline/diesel blend (80% gasoline by volume, denoted as G80). The injection strategy was adjusted to achieve the highest thermal efficiency at different intake pressures. The results showed that Low Temperature Heat Release (LTHR) was not observed in gasoline HCCI. However, 20% additional diesel could lower down the octane number and improve the autoignition reactivity of G80, which contributed to a weak LTHR, accounting for approximately 5% of total released heat. The combustion efficiency in gasoline DICI was higher than those in gasoline HCCI and G80 HCCI, while the exhaust loss and heat transfer loss in DICI mode were higher than those in HCCI mode.
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
2017-01-2291
Sandro Gail, Takashi Nomura, Hitoshi Hayashi, Yuichiro Miura, Katsumi Yoshida, Vinod Natarajan
Abstract 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
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
2017-01-2295
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
2017-01-2296
Andreas Glawar, Fabian Volkmer, Yanyun Wu, Adrian Groves
Abstract 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 employ direct-injection technology and many markets in Asia are also seeing an increasingly rapid uptake. However, with the adoption of GDI engine technology, which is able to push the boundaries of engine efficiency, new challenges are starting to arise such as injector nozzle deposits, which can adversely affect performance. Multi-hole solenoid actuated fuel injectors are particularly vulnerable to deposits formed when operated on some market fuels. In order to address this challenge, the development of a reliable industry test platform for injector cleanliness in GDI engines is currently underway in both the US and Europe.
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.
2017-10-08
Journal Article
2017-01-2346
Hong Liu, Jiajia Jin, Hongyu Li, Kazuo Yamamori, Toyoharu Kaneko, Minoru Yamashita, Liping Zhang
Abstract It has been long established fact that fuel economy is a key driving force of low viscosity gasoline engine oil research and development considered by the original equipment manufacturers (OEMs) and lubricant companies. The development of low viscosity gasoline engine oils should not only focus on fuel economy improvement, but also on the low speed pre-ignition (LSPI) prevention property. In previous LSPI prevention literatures, the necessity of applying Ca/Mg-based detergents system in the engine oil formulations was proposed. In this paper, we adopted a specific Group III base oil containing Ca-salicylate detergent, borated dispersant, Mo-DTC in the formulation and investigated the various effects of Mg-salicylate and Mg-sulfonate on the performance of engine oil. It was found that Mg-sulfonate showed a significant detrimental impact on silicone rubber compatibility while the influence from Mg-salicylate remains acceptable.
2017-10-08
Journal Article
2017-01-2370
Matthieu Lecompte, Jerome Obiols, Jerome Cherel, Stephane Raux
Abstract Diesel Exhaust Fluid (DEF) like Adblue® is a urea/water solution injected upstream from the SCR catalyst. Urea decomposes into ammonia (NH3) which acts as reducing agent in the de-NOx reaction process. However, incomplete decomposition of urea can lead to unwanted deposits formation, thereby resulting into backpressure increase, loss of NOx reduction efficiency, and durability issues. The phenomenon is aggravated at low temperatures and can lead to restriction or stop of DEF injection below certain exhaust temperatures. This paper focuses on the influence of the additivation of DEF on deposits formation in a passenger car close-coupled SCR on filter Diesel exhaust line installed in a laboratory flow bench test. The behavior of two different additivated DEF was compared to Adblue® in terms of deposits formation on the mixer and SCRF canning at different temperatures comprised between 240°C and 165°C, and different air flows.
2017-10-08
Journal Article
2017-01-2356
Hyun-Soo Hong, Christopher Engel, Brian Filippini, Sona Slocum, Farrukh Qureshi, Tomoya Higuchi
Abstract Improving vehicle fuel economy is a major consideration for original equipment manufacturers (OEMs) and their technology suppliers worldwide as government legislation increasingly limits carbon dioxide emissions. At the same time that automotive OEMs have been driving toward lower viscosity axle oils to improve fuel economy, OEMs have worked to improved durability over an extended drain interval. These challenges have driven the use of API group III and/or API group IV base oils in most factory fill axle oils. This paper details the development of a novel lower viscosity SAE 75W-85 axle technology based on group II base oil that rivals the performance of a PAO-based axle oil and challenges the conventional wisdom of not using group II base oils in fuel efficient axle oils.
2017-10-08
Journal Article
2017-01-2386
Naoki Ohya, Kohei Hiyama, Kotaro Tanaka, Mitsuru Konno, Atsuko Tomita, Takeshi Miki, Yutaka Tai
Abstract Diesel engines have better fuel economy over comparable gasoline engines and are useful for the reduction of CO2 emissions. However, to meet stringent emission standards, the technology for reducing NOx and particulate matter (PM) in diesel engine exhaust needs to be improved. A conventional selective catalytic reduction (SCR) system consists of a diesel oxidation catalyst (DOC), diesel particulate filter (DPF), and urea-SCR catalyst. Recently, more stringent regulations have led to the development of SCR systems with a larger volume and increased the cost of such systems. In order to solve these problems, an SCR catalyst-coated DPF (SCR/DPF) is proposed. An SCR/DPF system has lower volume and cost compared to the conventional SCR system. The SCR/DPF catalyst has two functions: combustion of PM and reduction of NOx emissions.
2017-10-08
Journal Article
2017-01-2375
Akihiro Niwa, Shogo Sakatani, Eriko Matsumura, Takaaki Kitamura
Abstract In the urea SCR system, urea solution is injected by injector installed in the front stage of the SCR catalyst, and NOx can be purified on the SCR catalyst by using NH3 generated by the chemical reaction of urea. NH3 is produced by thermolysis of urea and hydrolysis of isocyanic acid after evaporation of water in the urea solution. But, biuret and cyanuric acid which may cause deposit are sometimes generated by the chemical reactions without generating NH3. Spray behavior and chemical reaction of urea solution injected into the tail-pipe are complicated. The purpose of this study is to reveal the spray behavior and NH3 generation process in the tail-pipe, and to construct the model capable of predicting those accurately. In this report, the impingement spray behavior is clarified by scattered light method in high temperature flow field.
2017-10-08
Journal Article
2017-01-2427
Suresh Kumar Kandreegula, Rahul Jain, Shivdayal Prasad, Rahul Machiya, Avinash Mandyam
Abstract Automotive vehicle includes various systems like engine, transmission, exhaust, air intake, cooling and many more systems. No doubt the performance of individual system depends upon their core design. But for performance, the system needs to be fastened properly. In automotive, most of the joints used fasteners which helps in serviceability of the components. There are more than thousands of fasteners used in the vehicle. At various locations, we found issue of bolt loosening and because of this design intent performance has not met by the system. During product development of ECS (Engine cooling system), various issues reported to loosening the bolt. The pre-mature failure of bolt loosening, increases the interest in young engineers for understanding the behavior of fastener in vehicle running conditions. This paper focuses on the design of wedge shape of washer to avoid bolt loosening.
2017-10-08
Journal Article
2017-01-2400
Yanlong Wu, Jason Ferns, Hu Li, Gordon Andrews
Abstract Hydrogenated Vegetable Oil (HVO) diesel fuels have the potential to provide a reduced carbon footprint for diesel engines and reduce exhaust emissions. Therefore, it is a strong candidate for transport and diesel powered machines including electricity generators and other off-road machines. In this research, a waste cooking oil derived HVO diesel was investigated for its combustion and emission performance including ignition delays, size segregated particulate number emissions and gaseous emissions. The results were compared to the standard petroleum diesel. A EURO5 emission compliant three litre, direct injection, intercooled IVECO diesel engine equipped with EGR was used which has a maximum power output of 96kW. The engine was equipped with an integrated DOC and DPF aftertreatment system. Both the upstream and downstream of the aftertreatment emissions were measured. The tests were conducted at different RPM and loads at steady state conditions.
2017-10-08
Journal Article
2017-01-2434
Srinivasan Paulraj, Saravanan Muthiah
Abstract Traditionally driveline ratios are selected based on trial and error method of proto vehicle testing. This consumes lot of time and increases overall vehicle development effort. Over last few decades, simulation-based design approach has been extensively used to alleviate this problem. This paper describes torque converter and final drive ratio (FDR) selection at concept phase for new Automatic Transmission (AT) vehicle development. Most of the critical data required for simulating vehicle performance and fuel economy (FE) targets were not available (e.g. shift map, clutch slip map, pedal map, dynamic torque, coast down, etc.) at an initial stage of the project. Hence, the risk for assuming right inputs and properly selecting FDR/Torque converter was particularly high. Therefore, a validated AVL Cruise simulation model based on an existing AT vehicle was used as a base for new AT vehicle development to mitigate the risk due to non-availability of inputs.
2017-10-08
Journal Article
2017-01-2431
Michitaka Yamamoto, Takayuki Hosogi, Tetsuji Watanabe, Yuki Nishida
Abstract Over the past decades, the automotive industry has made significant efforts to improve engine fuel economy by reducing mechanical friction. Reducing friction under cold conditions is becoming more important in hybrid vehicle (HV) and plug-in hybrid vehicle (PHV) systems due to the lower oil temperatures of these systems, which results in higher friction loss. To help resolve this issue, a new internal gear fully variable discharge oil pump (F-VDOP) was developed. This new oil pump can control the oil pressure freely over a temperature range from -10°C to hot conditions. At 20°C, this pump lowers the minimum main gallery pressure to 100 kPa, thereby achieving a friction reduction effect of 1.4 Nm. The developed oil pump achieves a pressure response time constant of 0.17 seconds when changing the oil pressure from 120 kPa to 200 kPa at a temperature of 20°C and an engine speed of 1,600 rpm.
2017-10-08
Journal Article
2017-01-2445
Santosh Deshmane, Onkar P. Gurav, Vipul Sahu
Abstract Today’s automotive industry is facing cutthroat competition, especially in passenger vehicle business. Manufacturers around the globe are developing innovative and new products keeping focus on end customer; thus customer's opinion and perception about the product has become a factor of prime importance. Customer touch points such as gear shift lever, clutch, brakes, steering etc. are thus gaining more and more importance. Car companies are trying to induce more and more luxuries in these touch points so that they impress customer and create a positive opinion about the product. On the other hand manufacturers are also trying to manage profits. Companies thus need to find the best fit solution for improvising customer touch points with optimized costs. The performance of these touch points is driven by subsystems of mechanical components like mechanical linkage.
2017-10-08
Journal Article
2017-01-2436
Santosh Deshmane, Onkar Gangvekar, Samson Rajakumar
Abstract In today’s competitive automobile market, driver comfort is at utmost importance and the bar is being raised continuously. Gear Shifting is a crucial customer touch point. Any issue or inconvenience caused while shifting gear can result into customer dissatisfaction and will impact the brand image. While there are continual efforts being taken by most of the car manufactures, “Double Bump” in gearshift has remained as a pain area and impact severely on the shift feel. This is more prominent in North-South (N-S) transmissions. In this paper ‘Double Bump’ is a focus area and a mathematical / analytical approach is demonstrated by analyzing ‘impacting parameters’ and establishing their co-relation with double bump. Additionally, the results are also verified with a simulation model.
2017-10-08
Journal Article
2017-01-2446
Pengchuan Wang, Nikolaos Katopodes, Yuji Fujii
Abstract Wet clutch packs are the key component for gear shifting in the step-ratio automatic transmission system. The clutch plates are coupled or de-coupled to alter gear ratios based on the driver’s actions and vehicle operating conditions. The frictional interfaces between clutch plates are lubricated with automatic transmission fluid (ATF) for both thermal and friction management. In a 10-speed transmission, there may be as many as 6 clutch packs. Under typical driving conditions, 2 to 3 clutch packs are open, shearing ATF and contributing to energy loss. There is an opportunity to improve fuel economy by reducing the associated viscous drag. An important factor that directly affects clutch drag is the clearance between rotating plates. The axial position of clutch plates changes continuously during operation. It is known in practice that not only the total clearance, but also its distribution between the plates affects the viscous drag.
2017-10-08
Journal Article
2017-01-2341
Kongsheng Yang, Kristin A. Fletcher, Jeremy P. Styer, William Y. Lam, Gregory H. Guinther
Abstract Countries from every region in the world have set aggressive fuel economy targets to reduce greenhouse gas emissions. To meet these requirements, automakers are using combinations of technologies throughout the vehicle drivetrain to improve efficiency. One of the most efficient types of gasoline engine technologies is the turbocharged gasoline direct injection (TGDI) engine. The market share of TGDI engines within North America and globally has been steadily increasing since 2008. TGDI engines can operate at higher temperature and under higher loads. As a result, original equipment manufacturers (OEMs) have introduced additional engine tests to regional and OEM engine oil specifications to ensure performance of TGDI engines is maintained. One such engine test, the General Motors turbocharger coking (GMTC) test (originally referred to as the GM Turbo Charger Deposit Test), evaluates the potential of engine oil to protect turbochargers from deposit build-up.
2017-10-08
Journal Article
2017-01-2345
Ashutosh Gupta, Rachel Seeley, Huifang Shao, Joe Remias, Joseph Roos, Zhi Wang, Yunliang Qi
Abstract Low Speed Pre-Ignition (LSPI), also referred to as superknock or mega-knock 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 pre-ignition 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
2017-01-2366
Wenzheng Xia, Yi Zheng, Xiaokun He, Dongxia Yang, Huifang Shao, Joesph Remias, Joseph Roos, Yinhui Wang
Abstract Because of the increased use of gasoline direct engine (GDI) in the automobile industry, there is a significant need to control particulates from GDI engines based on emission regulations. One potential technical approach is the utilization of a gasoline particulate filter (GPF). The successful adoption of this emission control technology needs to take many aspects into consideration and requires a system approach for optimization. This study conducted research to investigate the impact of vehicle driving cycles, fuel properties and catalyst coating on the performance of GPF. It was found that driving cycle has significant impact on particulate emission. Fuel quality still plays a role in particulate emissions, and can affect the GPF performance. Catalyzed GPF is preferred for soot regeneration, especially for the case that the vehicle operation is dominated by congested city driving condition, i.e. low operating temperatures.
2017-10-08
Journal Article
2017-01-2299
Susumu Nagano, Nozomi Yokoo, Koji Kitano, Koichi Nakata
Abstract The effects of high boiling point fuel additives on deposits were investigated in a commercial turbocharged direct injection gasoline engine. It is known that high boiling point substances have a negative effect on deposits. The distillation end points of blended fuels containing these additives may be approximately 15°C higher than the base fuel (end point: 175°C). Three additives with boiling points between 190 and 196°C were examined: 4-tert-Butyltoluene (TBT), N-Methyl Aniline (NMA), and 2-Methyl-1,5-pentanediamine (MPD). Aromatics and anilines, which may be added to gasoline to increase its octane number, might have a negative effect on deposits. TBT has a benzene ring. NMA has a benzene ring and an amino group. MPD, which has no benzene ring and two amino groups, was selected for comparison with the former two additives.
2017-10-08
Technical Paper
2017-01-2378
Takayuki Ogata, Mikio Makino, Takashi Aoki, Takehide Shimoda, Kyohei Kato, Takahiko Nakatani, Koji Nagata, Claus Dieter Vogt, Yoshitaka Ito, Dominic Thier
Abstract In order to meet the challenging CO2 targets beyond 2020 despite keeping high performance engines, Gasoline Direct Injection (GDI) technology usually combined with charged aspiration is expanding in the automotive industry. While providing more efficient powertrains to reduce fuel consumption one side effect of GDI is the increased particle formation during the combustion process. For the first time for GDI from September 2014 there is a Particle Number (PN) limit in EU of 6x10 sup 12 #/km, which will be further reduced by one order of magnitude to 6x10 sup 11 #/km effective from September 2017 to be the same level as applied to Diesel engines. In addition to the PN limit of the certification cycle NEDC further certification of Real Driving Emissions (RDE) including portable PN measurements are under discussion by the European Commission. RDE test procedure requires stable and low emissions in a wide range of engine operations and durable over a distance of 160 000 km.
2017-10-08
Technical Paper
2017-01-2230
Nizar F.O. Al-Muhsen, Guang Hong
Abstract Ethanol as a renewable fuel has been used widely in vehicles. Dual fuel injection is one of the new techniques in development for increasing the engine’s thermal efficiency and reducing the pollutant emissions. This study reports experimental investigation to the dual ethanol fuel injection with a focus on the effect of spark timing on the engine performance at different volumetric ratios of ethanol directly injected to ethanol port injected. Experiments were conducted on a single cylinder 250cc spark ignition engine at two engine loads and 3500 RPM. The spark timing was varied from 15 to 42 CAD bTDC at the light load and from 15 to 32 CAD bTDC at the medium load, while the volumetric ratio of direct injection (DI%) was varied from 0% to 100%.
2017-10-08
Technical Paper
2017-01-2286
A S Ramadhas, Punit Kumar Singh, Reji Mathai, Ajay Kumar Sehgal
Abstract Ambient temperature conditions, engine design, fuel, lubricant and fuel injection strategies influence the cold start performance of gasoline engines. Despite the cold start period is only a very small portion in the legislative emission driving cycle, but it accounts for a major portion of the overall driving cycle emissions. The start ability tests were carried out in the weather controlled transient dynamometer - engine test cell at different ambient conditions for investigating the cold start behavior of a modern generation multi-point fuel injection system spark ignition engine. The combustion data were analyzed for the first 200 cycles and the engine performance and emissions were analyzed for 300 s from key-on. It is observed that cumulative fuel consumption of the engine during the first 60 s of engine cold starting at 10 °C was 60% higher than at 25 °C and resulted in 8% increase in the value of peak speed of the engine.
2017-10-05
Journal Article
2017-01-9284
Sayan Biswas, Li Qiao
Abstract Gas engines often utilize a small-volume pre-chamber in which fuel is injected at near stoichiometric condition to produce a hot turbulent jet which then ignites the lean mixture in the main chamber. Hot jet ignition has several advantages over traditional spark ignition, e.g., more reliable ignition of extra-lean mixtures and more surface area for ignition resulting in faster burning and improved combustion burn time. Our previous experimental results show that supersonic jets could extend the lean flammability limit of fuel/air mixtures in the main chamber in comparison to subsonic jets. The present paper investigated the characteristics of supersonic hot jets generated by combustion of stoichiometric H2/air in a pre-chamber to understand the ignition mechanism of ultra-lean mixtures by supersonic hot jets.
2017-10-05
Journal Article
2017-01-9286
David Oh, Martin Brouillette, Jean-Sebastien Plante
Abstract A vortex-stratified combustion process for hydrogen-fueled reciprocating internal combustion engines is introduced to increase the thermal efficiency by reducing the convective heat transfer losses to the surrounding walls during combustion. The process imposes a highly ordered rotational field upon the charge in a separate, transverse, cylindrically shaped combustion chamber by means of channels that connect with the main chamber enclosed by the engine cylinder and piston. Gaseous hydrogen is injected directly during the compression stroke, while air enters into the combustion chamber tangentially and preferentially along the circumference due to the Coandă effect. The two streams entrain one another and develop into a vigorous vortex by virtue of the chamber and channel geometries.
Viewing 181 to 210 of 44126