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Training / Education
2015-03-02
Public awareness regarding pollutants and their adverse health effects has created an urgent need for engineers to better understand the combustion process as well as the pollutants formed as by-products of that process. To effectively contribute to emission control strategies and design and develop emission control systems and components, a good understanding of the physical and mathematical principles of the combustion process is necessary. This seminar will bring issues related to combustion and emissions "down to earth," relying less on mathematical terms and more on physical explanations and analogies.
Event
2014-10-21
This session covers topics regarding new CI and SI engines and components. This includes analytical, experimental, and computational studies covering hardware development as well as design and analysis techniques.
Event
2014-10-21
Separate sub-sessions cover zero-dimensional, one-dimensional, and quasi-dimensional models for simulation of SI and CI engines with respect to: engine breathing, boosting, and acoustics; SI combustion and emissions; CI combustion and emissions; fundamentals of engine thermodynamics; numerical modeling of gas dynamics; thermal management; mechanical and lubrication systems; system level models for controls; system level models for vehicle fuel economy and emissions predictions.
Event
2014-10-21
This session covers the Power Cylinder: piston, piston rings, piston pins, and connecting rods. The papers include information on reducing friction and increasing fuel economy, improving durability by understanding wear, and decreasing oil consumption and blow-by.
Event
2014-10-21
This session focuses on technologies such as advanced and partially mixed combustion, cooled EGR boosting, ignition and direct injection technologies, pressure boosting, intelligent combustion, thermal efficiency, fully variable valvetrains, and other new and developing technologies. Papers focused on waste heat recovery technologies should be submitted to HX102/103.
Event
2014-10-21
This session focuses on technologies such as advanced and partially mixed combustion, cooled EGR boosting, ignition and direct injection technologies, pressure boosting, intelligent combustion, thermal efficiency, fully variable valvetrains, and other new and developing technologies. Papers focused on waste heat recovery technologies should be submitted to HX102/103.
Event
2014-10-20
Mixed modes with both flame propagation and slow auto ignition. Distinct from SI knock: autoignition is desired and will not ruin the engine. Papers describing experiments and test data, simulation results focused on applications, fuel/additive effects, and SACI mode change are invited and will be placed in appropriate sub-sessions. Papers with an emphasis on the modeling aspects of combustion are encouraged to be submitted into PFL 110 or PFL120 modeling sessions.
Technical Paper
2014-10-13
Cyrille Frottier, Marc Sens, Michael Rieß, Malte Wigger, Andreas Benz, Noriyuki Maekawa, Koji Onishi, Kazuhiro Oryoji, Kenichi Machida
In the near future, emission standards legislation will become more and more restrictive for gasoline engines. Introduction of direct injection made the decrease of particulate number very challenging and many mechanical and physical features have been developed for reducing it on combustion and after-treatment side. IAV GmbH, Hitachi Automotive Systems Europe GmbH and Hitachi Automotive Systems, Ltd. cooperated for combustion enhancement by using Hitachi components dedicated to high pressure injection. This paper will focus on this new high pressure fuel system improving droplets atomization and consequently combustion efficiency. Hitachi system includes a fuel pump and injectors operating up to 30 MPa. New spray patterns have been designed in CFD (Computational Fluid Dynamics) simulation for a specific engine (boosted engine with 1.4L and direct injection). Those have been designed at IAV GmbH keeping a compact spray pattern and a reduced spray penetration. Then, the injectors have been manufactured by Hitachi Automotive Systems, Ltd. with an additional feature avoiding any needle bouncing at high pressure injection.
Technical Paper
2014-10-13
Michael Bunce, Hugh Blaxill
With an increasing global awareness of the need to conserve fuel resources and reduce carbon dioxide emissions, the automotive sector has been seeking gains in engine efficiency. One such method for achieving these gains on a spark ignition (SI) engine platform is through lean burn operation. Lean burn operation has demonstrated the ability to increase thermal efficiency, but this increase is often accompanied by increases in criteria pollutants, namely nitrogen oxides (NOx). By contrast, ultra-lean operation (λ>2) has demonstrated the ability to increase thermal efficiency and significantly reduce NOx due primarily to lower mean gas temperatures. Turbulent Jet Ignition (TJI), a pre-chamber-based combustion system, is a technology that enables ultra-lean operation through an effective de-coupling of the λ values in the pre-chamber and the main combustion chamber. TJI is also an effective knock mitigation system due to the distributed nature of main chamber ignition, resulting in rapid burn rates.
Technical Paper
2014-10-13
Patrick Smith, Wai K. Cheng, John Heywood
The effects of piston top-land crevice size on the indicated fuel conversion efficiency are assessed in a single cylinder SI engine with 465 cc displacement. The operating conditions are at 3.6 and 5.6 bar net indicated mean effective pressure (NIMEP), and at 1500 and 2000 rpm speeds. The crevice volume is varied from 524 to 1157 mm^3 by changing the top land height from 3 to 7 mm, and by changing the top-land clearance from 0.247 to 0.586 mm. For a 1000 mm3 reduction in the top land crevice volume (measured cold), the indicated net fuel conversion efficiency increases by 1.8 percentage points at 3.6 bar NIMEP, and by 1.6 percentage points at 5.6 bar NIMEP. The results are not sensitive to the engine speeds under test. These values are consistent with a simple crevice filling and discharge/oxidation model.
Technical Paper
2014-10-13
Gautam Kalghatgi, Robert Head, Junseok Chang, Yoann Viollet, Hassan Babiker, Amer Amer
As SI engines strive for higher efficiency they are more likely to encounter knock and fuel anti-knock quality, which is currently measured by RON and MON, becomes more important. However, RON and MON scales are based on primary reference fuels – mixtures of iso-octane and n-heptane – whose autoignition chemistry is significantly different from that of practical fuels. Hence RON or MON alone can truly characterize a gasoline for its knock behavior only at their respective operating conditions. The true anti-knock quality of fuel is given by the octane index, OI = RON –KS where S = RON – MON, is the sensitivity. K depends on the pressure and temperature evolution in the unburned gas during the engine cycle and is negative in modern engines. Thus the same gasoline can match different PRF fuels at different operating conditions. In this paper we propose that the gasoline is ranked against toluene /n-heptane mixtures (toluene reference fuel, TRF). The gasoline is assigned a Toluene Number (TN), which is the volume percent of toluene in the TRF which matches the gasoline for knock in the CFR RON test.
Technical Paper
2014-10-13
Ben Leach, Richard Pearson, Rana Ali, John Williams
Engine downsizing is a key approach employed by many vehicle manufacturers to help meetfleet average CO2 emissions targets. With gasoline engines in particular reducing engine swept volume while increasing specific output via technologies such as turbocharging, direct injection (DI) and variable valve timing can significantly reduce frictional and pumping losses in engine operating areas commonly encounteredin legislative drive cycles. These engines have increased susceptibility to abnormal combustion phenomena such asknock due to the high brake mean effective pressures which they generate. This ultimately limits fuel efficiency benefits by demanding use of a lower geometric compression ratio and sub-optimal late combustion phasing at the higher specific loads experienced by the engines. The lower expansion ratio and retarded combustion in turn increase the exhaust gas temperature, which often leads to a need add extra fuel that cannot be fully combusted in order to cool and protect engine components from thermal damage.Optimising theengine design for use with a fuel with an increased research octane number (RON) allows the adoption of a higher compression ratio.
Technical Paper
2014-10-13
Karel Steurs, Christopher Blomberg, Konstantinos Boulouchos
Knock is often the main limiting factor for brake efficiency in spark ignition engines and is mostly attributed to auto-ignition of the unburned mixture in front of the flame. The design of future engines would therefore benefit greatly of accurate models to predict the occurrence of knock. In order to study knock in a systematic way, experiments with ethanol and iso-octane have been carried out on a 250cc single cylinder spark ignition test engine with variable intake temperatures at wide open throttle and stoichiometric premixed fuel/air mixtures. At different speeds and intake temperatures spark angle sweeps have been performed ranging from late timing and non-knocking combustion up to early timing and strong knocking conditions. The in-cylinder pressure traces have been recorded for all operating points and are used to detect knocking conditions. A 1-D engine simulation model is used to calculate the heat release rates and burned-/unburned zone temperatures are computed. Special attention is given to the heat transfer in the cylinder and the intake port during the intake and compression strokes to accurately determine the temperature of the unburned mixture and the related sensitivities are explored.
Technical Paper
2014-10-13
Zhengyang Ling, Alexey Burluka, Ulugbek Azimov
Replacing the conventional fossil fuel totally or partially with alcohols or ethers in spark-ignition (SI) engine is a promising way to reduce pollutant emissions. A large number of studies on alcohol-containing blends in SI engines could be found in the literature. Nonetheless, investigations of ether-containing blends are by far much less numerous, especially for modern boosted engines. Blending with ether compounds might change the burning rate at high pressure, which consequently changes the anti-knock properties of these fuels and leads to a deterioration in the vehicle drivability. This work reports experiments carried out in two one-cylinder engines: one is a naturally aspirated, variable compression ratio engine, and the other is a strongly charged optical engine. Three fuels with different RON and MON numbers were tested: Iso-octane, a blend Ethyl Tert Butyl Ether (ETBE) with a primary reference fuel, and a commercial gasoline fuel containing 5% by volume of ethanol (E05). The experimental results show a significant difference of knock boundaries of three fuels in the boosted engine at the initial, i.e. equivalent of the intake manifold, pressure of 1.6bar, and almost similar knock boundaries under different compression ratios in the naturally aspirated engine.
Technical Paper
2014-10-13
Martin Pechout, Ales Dittrich, Michal Vojtisek-Lom
One of the pathways to carbon-neutral, sustainable transportation and to decreasing dependency on petroleum is to find out drop-in alternative fuels for gasoline engines. In the general fleet, the usage of ethanol is limited to blend with relatively small concentrations due to large differences compared to gasoline. Compared to ethanol, butanol, which can be produced from non-food biomass, exhibits lower hygroscopicity and aggressivity, and has volumetric energy density closer to gasoline. This paper reports on the experimental combustion study, where an ordinary, unmodified port fuel injection gasoline engine was operated on blends of gasoline with various concentrations of two butanol isomers (n-butanol and iso-butanol) and on pure butanol. A naturally aspirated, three-cylinder, four-valves-per-cylinder, 1.2 dm3 Škoda 1.2 HTP engine has been tested at steady-state operating points on an engine dynamometer. The operating points were selected to cover both common and uncommon yet potentially problematic operating conditions.
Technical Paper
2014-10-13
Michael Storch, Lars Zigan, Michael Wensing, Stefan Will
For future CO2- reductions of spark ignition (SI) engines, the combination of modern engine operation concepts, e.g. direct injection (DI), and the use of biofuels such as ethanol is essential. However, DI concepts have the drawback of higher particulate matter emission as compared to port fuel injection. Especially when driven with biofuels, the operation of direct injection spark ignition engines (DISI) requires a deeper insight into particulate formation processes. Biofuel components show completely different fuel properties as compared to gasoline and lead to a very complex chain of effects in engine combustion. Therefore the effects of varying composition on mixture formation, combustion and soot formation can hardly be predicted. Previous studies report opposing results about using ethanol blended gasoline fuels for engine applications. Some describe increasing, while others state decreasing particulate emissions for higher ethanol contents in the fuel. The reason for these contradictory results is unclear and must be further addressed.
Technical Paper
2014-10-13
Magnus Sjöberg, Wei Zeng, Daniel Singleton, Jason M. Sanders, Martin A. Gundersen
It is well known that well-mixed lean or dilute SI engine operation can provide improvements of the fuel economy (FE) relative to that of traditional well-mixed stoichiometric SI operation. However, the potential is limited by the onset of unstable combustion for low fuel/air-equivalence (phi) ratios. This work examines the use of two methods for improving combustion stability for lean operation, namely multi-pulse transient plasma ignition and intake air preheating. These two methods are compared to standard SI operation using a normal inductive ignition system without intake air preheating. E85 is the fuel chosen for this study. The experimental results from single-cylinder testing show that the FE improvement for lean operation with the regular spark system without intake air preheating amounts to 12% for phi = 0.67. Using a combination of intake air preheating and multi-pulse ignition, the engine can be operated stably at lower phi, enabling a larger improvement of FE, amounting to 17% for phi = 0.59.
Technical Paper
2014-10-13
Yuanzhe Zhong, Sahil Sane
Electronic controls in internal combustion engines require an in-cylinder combustion sensor to produce a feedback signal to the ECU (Engine Control Unit). Recent research indicated that the ion current sensor has many advantages over the pressure transducer, related mainly to lower cost. Modified glow plugs in diesel engines, and fuel injectors in both gasoline and diesel engines can be utilized as ion current sensors without the addition any part or drilling holes in the cylinder head needed for the pressure transducer. Multi sensing fuel injector (MSFI) system is a new technique which instruments the fuel injector with an electric circuit to perform multiple sensing tasks including functioning as an ion sensor in addition to its primary task of delivering the fuel into the cylinder. It is necessary to fundamentally understand MSFI system. In this study the author will firstly explore the influence of piston motion (as one side of variable capacitance) on the ion sensor signal through modeling and simulation, and then look into the origin of the MSFI signal of fuel injection; and finally the author will look at how to analyze MSFI signal to duplicate the injection command profile for on-board diagnostics (OBD).
Technical Paper
2014-10-13
Le-zhong Fu, Zhijun Wu, Liguang Li, Xiao Yu
Internal combustion rankine cycle engine could have high fuel efficiency and ultra-low emission performance. In an ideal ICRC engine, high temperature liquid water is injected into the cylinder near top dead center to control the combustion temperature and cylinder pressure rise rate, and then enhances the thermo efficiency and work. The reason is the extra work fluid into the cylinder in the form of water vapor which can make use of the combustion heat more effectively. Moreover, the high temperature water can be heated up through heat exchanger by exhaust gas and engine cooling system, and the waste heat carried away by engine cooling system and exhaust gas can be recovered and utilized. In this paper, a retrofitted, single-cylinder, air-cooled SI engine with propane fuel is adopted in the test. To simplify the experiments preparation, water is heated up in an electric heater in a high-pressure rail and injected into the cylinder with a solenoid diesel injector. The water injection pressure is obtained from a N2 tank and amplified through the pressure amplifier up to 15~25MPa.
Technical Paper
2014-10-13
Florian Kleiner, Marcel Kaspar, Christina Artmann, Hans-Peter Rabl
In coming years a special focus in the field of gasoline engines will be on downsized concepts and highly-charged gasoline direct injection engines. These represent the result of stricter emission laws, higher customer requirements, greater environmental awareness as well as high demands on materials and resources. Especially at cold start and the warm-up operation GDI engines have an issue with oil dilution. Fuel gets into the oil pan and is mixed with the engine oil so that the physical and chemical properties of the engine oil are changed. With the adjustment of the engine operating points to higher mean effective pressures resulting in downsizing concepts also an additional increase of the fuel entry into the engine oil occurs. At the University of Applied Sciences Regensburg measurements were carried out at a direct injected gasoline engine with side located injector position. This engine with 1.8 l displacement disposes e.g. a Common-Rail Injection system up to 20 MPa, a variable camshaft regulation and a variable tumble system.
Technical Paper
2014-10-13
Habib Aghaali, Hans-Erik Angstrom
Turbocompound can utilize part of the exhaust energy on internal combustion engines; however, it increases exhaust back pressure, and pumping loss. To avoid such drawbacks, divided exhaust period (DEP) technology is combined with the turbocompound engine. In the DEP concept the exhaust flow is divided between two different exhaust manifolds, blowdown and scavenging, with different valve timings. This leads to lower exhaust back pressure and improves engine performance. Combining turbocompound engine with DEP has been theoretically investigated previously and shown that this reduces the fuel consumption and there is a compromise between the turbine energy recovery and the pumping work in the engine optimization. However, the sensitivity of the engine performance has not been investigated for all relevant parameters. The main aim of this study is to analyse the sensitivity of this engine architecture in terms of break specific fuel consumption to different parameters concerning the gas exchange such as blowdown valve timing, scavenging valve timing, blowdown valve size, scavenging valve size, discharge coefficients of blowdown and scavenging valves, turbine efficiency and turbine size.
Technical Paper
2014-10-13
Guillaume Pilla, Loic Francqueville
Reduction of CO2 emissions is becoming one of the great challenges for future gasoline engines. Downsizing is one of the most promising strategy to achieve this reduction, though it facilitates knock phenomena. Therefore downsizing has to be associated with knock limiting technologies such as increased aerodynamics, dilution and thermal measures. High dilution levels allow to push back the knocking limit thus enhancing engine efficiency. The maximum gain of efficiency is therefore closely dependent on the dilution limit. State of the art shows that combustion initiation can be critical for highly diluted mixture combustion. If spark ignition systems are commonly used in GDI engines, they have known few evolutions since their invention. By optimizing key parameters such as spark duration, energy or size, it can be expected significant gain in dilution acceptance on GDI engines. This paper presents the results of innovative ignition systems tests on the dilution acceptance of a 400cc optical GDI engine.
Technical Paper
2014-10-13
Bo Hu, Colin Copeland, Chris Brace, Sam Akehurst, Alessandro Romagnoli, Ricardo Martinez-Botas, J.W.G Turner
Turbocharged engines when operating at high engine speed and load cannot fully utilize the exhaust energy as the wastegate is opened to prevent overboost. Meanwhile, engines equipped with pressure charging systems are more prone to knock partly due the increased intake temperature. The expansion-cooling concept thus is conceived to reduce the intake temperature by recovering some otherwise unexploited exhaust energy. This concept can be applied to any twin charged (supercharger and turbocharger) engine system with an intercooler in between. The turbocharging system is designed to achieve maximum utilization of the exhaust energy, from which the intake charge is overboosted. After the intercooler, the supercharging system behaves like a turbine to expand the over-compressed intake charge and reduce its temperature whilst recovering some energy through the connection to the camshaft. It is anticipated that such a concept has benefits for knock resistance and energy recovery while suffering higher pumping losses.
Technical Paper
2014-10-13
Mohd Farid Muhamad Said, Azhar Bin Abdul Aziz, Zulkanain Abdul Latiff, Amin Mahmoudzadeh Andwari, Shahril Nizam Mohamed Soid
Many efforts have been invested to improve the fuel efficiency of vehicles mainly for the local consumers. The production of a downsized turbocharged engine in the last quarter of 2011 proves that Malaysian is racing towards producing high efficiency engines along with other manufacturers. The effort does not only end there, several research activities on other alternative technology including cylinder deactivation (CDA) has begun. In this paper, the main research area is focus on the investigation of cylinder deactivation (CDA) technology on common engine part load conditions within Malaysian city driving operation. CDA mostly being applied on multi cylinders engines. It has the advantage in improving fuel consumption by reducing pumping losses at part load engine conditions. Here, the application of CDA on 1.6 liter four cylinders gasoline engine is studied. One-dimensional (1-D) engine modeling is performed to investigate the effect of intake and exhaust valve strategy on engine performance with CDA.
Technical Paper
2014-10-13
Pawel Magryta, Miroslaw Wendeker, Adam Majczak, Michal Bialy, Ksenia Siadkowska
Nowadays more sophisticated ways are search for alternative supply of combustion engines. One of the commonly used alternative fuels is hydrogen. On the market there are quite a number of passenger cars, which are powered by hydrogen fuel. The development of this technology is primarily connected with the introduction of hydrogen refueling stations, and hydrogen storage and distribution systems. We can predict that much faster popularization trend of hydrogen fuel would bring the possibility of modifying the existing fuel supply systems of internal combustion engines for use this environmentally friendly fuel. Adaptation of existing vehicles equipped with spark-ignition engines in the ability to support combustion by dosing additional dose of hydrogen would enable the introduction of this alternative fuel on a larger scale than at present. In order to verify the assumptions of the additive supplying hydrogen, simulation test model of a spark ignition engine, developed in the AVL BOOST software was presented in the article.
Technical Paper
2014-10-13
Tao Yin, Tie Li, Longhua Chen, Bin Zheng, Fei Zhao
Worldwide demands for better fuel economy and less pollutant emissions of automobiles are driving vehicle manufactures to seek further technical improvements in reciprocating engines. Spark ignited (SI) engines have a significant optimization potential by techniques such as supercharging, variable valve timing, downsizing, exhaust gas recirculation or direct injection. Each method distinctively influences the engine performance in variable operating conditions, which makes it complex to apply these techniques in a synergy pattern. Therefore, optimization of engine parameters is expected to make full use of the positive coupling techniques.This paper studies the effect of cooled EGR on fuel consumption and anti-knock performance of a boosted port fuel injection (PFI) SI engine. Experimental results show that the cooled EGR increases the thermal efficiency by 2%~18% depending on the operation conditions. Compared to low load operations, more improvements of the thermal efficiency are obtained at higher loads, primarily owing to the enhanced anti-knock performance, advanced combustion phasing, elimination of fuel-rich operations as well as reduced heat transfer loss with cooled EGR.
Technical Paper
2014-10-13
Bo Hu, Chris Brace, Sam Akehurst, Colin Copeland, J.W.G. Turner
One of the major limits for two-stage-regulated turbocharged SI engines is its large backpressure and the corresponding degraded combustion efficiency. Divided exhaust period (DEP) concept is an approach which has been proved to significantly reduce the backpressure while still maintaining the same engine performance. The standard layout of the DEP system only comprises of a single turbocharger. Two exhaust valves are separately functioned with one valve feeding the blow-down pulse to the turbine whilst the other valve targeting the scavenging by bypassing the turbine. This method can provide large BSFC improvement due to improved breathing characteristics and better combustion phasing. The DEP concept has only been applied to single turbocharged engines so far. However, it in its basic form is in no way restricted to one-stage system. This paper, for the first time, applied DEP concept to a two-stage-regulated downsized SI engine. By controlling the timing of the exhaust valves separately to feed the exhaust to the high-pressure-turbine or low-pressure turbine or the exhaust pipe, it is anticipated that such system could achieve even better breathing characteristics than the standard one-stage turbocharged engine.
Technical Paper
2014-10-13
Fabio Bozza, Vincenzo De Bellis, Daniela Siano
Control of knock phenomenon is becoming more and more important in modern SI engine, due to the tendency to develop high boosted turbocharged engines (downsizing). To this aim, improved modeling and experimental techniques are required to precisely define the maximum allowable spark advance. On the experimental side, the knock limit is identified based on some indices derived by the analysis of the in-cylinder pressure traces or of the cylinder block vibrations. The threshold levels of the knock indices are usually defined following an heuristic approach. On the modeling side, in the 1D codes, the knock is usually described by simple correlation of the auto-ignition time of the unburned gas zone within the cylinders. In addition, the latter methodology commonly refers to ensemble-averaged pressure cycles and, for this reason, does not take into account the cycle-by-cycle variations. In this work, an experimental activity is carried out to characterize the effects of cyclic dispersion on knock phenomena for different engine speeds, at full load operations and referring to a spark advance of borderline knock.
Technical Paper
2014-10-13
Lyes Tarabet, Mohand Said Lounici, Khaled Loubar, Mohand Tazerout
The use of computer engine cycle simulations, based on zero-dimensional (single zone or multi-zone) or multi-dimensional models, to aid engine systems design process has been largely applied and has become a popular tool because of combination of accurate results and reduced costs. In these models, the combustion sub-model plays a critical role in the overall engine simulation as it provides the heat release rate (HRR), which represents the combustion process for a given engine geometry and set of operating conditions. The determination of the experimental HRR is obtained solving the first law of Thermodynamics in the cylinder closed cycle with the aid of measured in-cylinder pressure. The widely used model in modern reciprocating Diesel engine applications to predict the HRR is the approximation by means of a correlation based on the combination of at least two Wiebe functions. This correlation has a characteristic S-shaped curve, which grows from zero indicating the start of combustion and tends exponentially to one indicating the end of combustion.
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