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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
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
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 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.
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.
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
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
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
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
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
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
Christopher Bannister
When evaluating the performance of new boosting hardware, it is a challenge to isolate the heat transfer effects inherent within measured turbine and compressor efficiencies. This work documents the construction of a lumped mass turbocharger model in the MatLab Simulink environment capable of predicting turbine and compressor metal and gas outlet temperatures based on measured or simulated inlet conditions. A production turbocharger from a representative 2.2L common rail diesel engine was instrumented to enable accurate gas and wall temperature measurements to be recorded under a variety of engine operating conditions. Initially steady-state testing was undertaken across the engine speed and load range in order that empirical Reynolds-Nusselt heat transfer relationships could be derived and incorporated into the model. Steady state model predictions were validated against further experimental data and an assessment made of the transient performance of the model during tip-in’s and tip-outs.
Technical Paper
2014-10-13
Jacek Andrzej Czarnigowski
The search for environmentally friendly fuels and ways of reducing carbon dioxide emissions is the main cause of a growing interest in gaseous fuels and corresponding fuel systems for internal combustion engines. To assure the expected environmental advantages with no detriment to the engine performance, these fuel systems need to be equipped with precise actuators – the gas injectors. The key input required in the process of designing and calibrating such fuel systems are precise characteristics of the injectors and understanding what affects these characteristics. The paper presents the results of experiments on the effects of supply pressure and supply voltage on the pulse gas injector opening time. Two characteristics have been investigated into: the opening lag time and the opening time. The opening lag was defined as the time between the occurence of a control signal and the moment of the valve’s starting to move. The lag determines the minimal duration of the control signal that can be executed by the injector, and thus the injector’s applicability.
Technical Paper
2014-10-13
Yongqiang Han, Jianjian Kang, Xianfeng Wang, Yang Chen, Zhichao Hu
Energy saving and environment protection has been two major subjects in the development of automobile industry. In the internal combustion engine, about 40% of fuel energy is released into the atmosphere through waste gas. The recovery and utilization of the heat from waste gas can realize the goals of energy saving and cost reducing. In fieldof waste heat recovery, the organic Rankine cycle (ORC) has good prospects and has been widely used.Turbo has been selected firstly as the expander in traditional ORC. However, turbo has disadvantages of high manufacturing cost and narrow applicable range. In this paper, a new organic Rankinecycle coupling free piston (ORC-FP) system used in theinternal combustion engine (ICE) exhaust heatrecovery is proposed and its working principle is introduced in detail.In this system, the free piston with constant force outputfunctions as expander in ORC and operates reciprocally to output workunder the driven of working fluid R245ca,which absorbs heat from waste gas and provides vapor power.
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.
Technical Paper
2014-10-13
Mohamadamin Shamsderakhshan, Shahaboddin Kharazmi
Diesel engines have widely used in past hundred years. During this time costly and extensive researches have been done to improve engine performance, which is going on. Important issues of these engines are higher specific power and efficiency and lower specific fuel consumption and pollutions formation. One of the best methods for engine performance improvement is matching a convenient turbocharger on engine. A turbocharger increases the engine air mass flow rate by increasing the inlet pressure and density, which causes fuel mass flow rate and power increase. The aim of this paper is to choose the convenient turbocharger for the OM355 naturally aspirated diesel engine and turn it to a turbocharged one. For this, 1D computer simulation code is used and simulation results are validated with experimental results. Finally, by selecting proper turbocharger, engine power increases about 50% and specific fuel consumption decreases about 4%. Moreover, effects of exhaust manifold geometry and ambient condition on performance parameters of the turbocharged diesel engine are investigated.
Technical Paper
2014-10-13
Qiyou Deng, Richard Burke
As the requirements of vehicle pollutant emissions and fuel consumption are getting stricter, engine downsizing through turbocharging to improve the efficiency of vehicles is becoming more popular. However, for now, the turbocharger models are based on characteristic maps derived from experimental measurements taken under steady conditions on dedicated gas stand facility. Under these conditions heat transfer is ignored and consequently the predictive performance of the model is compromised, particularly under the part load and dynamic operating conditions that are representative of real powertrain operation. Although some physics based models have been proposed to account for the thermal behaviour of the device, these require considerable experimental effort to determine the model parameters that is not practical for industrial applications. A more accurate model that is easily parameterised would benefit turbocharger-engine matching and engine controller design. This paper proposes to apply a dynamic mathematical model that uses a polynomial structure, the Volterra Series, for the modelling of the turbocharger system.
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
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
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
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
Patrick Smith, John Heywood, Wai Cheng
With ever tightening CO2 emissions standards, engine efficiency has jumped to the forefront of automotive engine focus. A proven way to realize efficiency gains is through the increase of engine compression ratio. Various experimental and simulation studies are compiled to quantify the effect of compression ratio on modern spark ignited engine efficiency. Four studies are taken from research conducted at the Sloan Automotive Laboratory at MIT and three are from the literature. Compression ratios range between 8 and 13.4 looking at gross indicated efficiency, net indicated efficiency, and brake efficiency. Curves of efficiency versus compression ratio are fit to the data points for each of the studies and normalized about a compression ratio of 10. Average curves for each of the three efficiency types across all data available show that increasing from a compression ratio of 10 to 13 results in relative increases of 5.1% for brake efficiency, 4.6% for gross indicated efficiency, and 4.5% for net indicated efficiency.
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
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
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
Timothy J. Jacobs, Louis Camilli, Matthias Neubauer
A key element to achieving vehicle emission certification for most light-duty vehicles using spark-ignition engine technology is prompt catalyst warming. Emission mitigation largely does not occur while the catalyst is below its “light-off temperature”, which may take several minutes to achieve when the engine starts from a cold condition. Such long periods of time are enough to fail a vehicle during its emission certification; it is necessary to minimize the catalyst warm up period to mitigate emissions as quickly as possible. One technique used to minimize catalyst warm up is to calibrate the engine in such a way that it delivers high temperature exhaust. At idle or low speed/low-low conditions, this can be done by advancing spark timing with a corresponding increase in fuel flow rate and / or leaning the mixture. Both approaches, however, encounter limits as combustion stability degrades, unburned hydrocarbon and carbon monoxide emissions rise excessively, and / or nitrogen oxide emissions rise excessively.
Technical Paper
2014-10-13
Pierre Brequigny, Fabien Halter, Christine Mounaïm-Rousselle, Bruno Moreau, Thomas Dubois
The current decrease in fossil energy resources requires a diversification of the liquid and gaseous fuels potentially consumable in internal combustion engines. The use of these fuels alters the combustion process and the heat released as well. In a Spark Ignition engine, the heat released is mainly piloted not only by the mixture reactivity but also by its sensitivity to stretch effects. Usually, the input parameter for CFD simulation is only the non stretched laminar combustion velocity. Former studies performed with different burner configurations have demonstrated a strong impact of stretch effects on the turbulent flame speed. Only few results can be found in the literature for SI engine configurations. The purposes of the present paper are first to evaluate stretch effects on the flame front propagation inside an optical SI-engine and to investigate the relative importance of these effects depending on the fuel considered. For this study, different fuels and mixture conditions presenting almost equivalent laminar flame speeds and thermo-dynamical properties have been selected.
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