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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.
Training / Education
2014-11-10
Engines can and do experience failures in the field in a variety of equipment, vehicles, and applications. On occasion, a single vehicle type or equipment family will even experience multiple engine failures leading to the inevitable need to determine what the most likely cause of one or all of those failures was. This comprehensive seminar introduces participants to the methods and techniques used to determine the most likely cause of an individual engine or group of engine failures in the field. The seminar begins with a review of engine design architecture and operating cycles, integration of the engine into the vehicle itself, and finally customer duty cycles and operating environments.
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
Wuqiang Long, Qiang Zhang, Jiangping Tian, Yicong Wang, Xiangyu Meng
To directly control the premixed combustion phasing, a novel method called Jet Controlled Compression Ignition (JCCI) is investigated. Experiments were conducted on a single cylinder natural aspirated diesel engine at 3000 r/min without EGR. Numerical model was validated by pressure and heat release rate curves at a fixed spark timing. The simulation results showed that the reacting active radical species with high temperature issued from ignition chamber played an important role on the onset of combustion in JCCI system. The combustion of diesel pre-mixtures was initiated rapidly by the combustion products issued from ignition chamber. Consequently, the experiments of spark timing sweep were conducted to verify the above deduction. The results showed a good linear relationship between spark timing and CA10 and CA50, which validated the ability for direct combustion phasing control in diesel premixed combustion. The NOx and Soot emissions gradually changed with decrease of spark advance angle.
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
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
John Thomas
Vehicle manufacturers among others are putting great emphasis on improving fuel economy (FE) of light-duty vehicles in the U.S. market, with significant FE gains being realized in recent years. The U.S. Environmental Protection Agency (EPA) data indicates that the aggregate FE of vehicles produced for the U.S. market has improved by 20% from model year (MY) 2005 to 2013. This steep climb in FE includes changes in vehicle choice, improvements in engine and transmission technology, and reducing aerodynamic drag, rolling resistance, and parasitic losses. The powertrain related improvements focus on optimizing in-use efficiency of the transmission and engine as a system, and may make use of what is termed downsizing and/or downspeeding. This study explores quantifying recent improvements in powertrain efficiency, viewed separately from other vehicle alterations and attributes (noting that most vehicle changes are not completely independent). A methodology is outlined to estimate powertrain efficiency for the U.S city and highway cycle tests using data from the EPA vehicle database.
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
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
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
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
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
Wei Guo, Henry Guo, Xiaowei Du, Daniel Wang
ABSTRACT In recent years, the temperature of automobile exhaust gas is on a rising trend due to lowering pollutant emissions and improving fuel economy, and exhaust gas temperature reaches as high as 1000 deg in the case of gasoline engine cars. Turbocharger is widely used to boost engine due to low emissions, fuel economy and low cost reasons. As one of the hot components, it is subjected extreme hostile environment. Against this background, stainless steel has been chosen extensively as a turbine housing material for the gasoline engine cars. However, stainless steel has become a material of great cost volatility due to high Nickel content to resist oxidation which price is expensive. Meanwhile, austenitic ductile iron possesses favorable thermal fatigue properties, good material cost stability and good castability. It is considered to be promising substitutions for the stainless steel in most of gasoline engine cars in which the exhaust gas temperature reaches up to 950 deg. Low levels of engine noise, vibration and harshness and high acceptance of vehicle sound quality are critical for achieving passenger preference and satisfaction in the modern passenger car.
Technical Paper
2014-10-13
Thomas Briggs, Terrence Alger, Barrett Mangold
A series of ignition systems were evaluated for their suitability for high-EGR SI engine applications. Testing was performed in a constant-volume combustion chamber and in a single-cylinder research engine, with EGR rates of up to 40% evaluated. All of the evaluated systems were able to initiate combustion at a simulated 20% EGR level, but not all of the resulting combustion rates were adequate for stable engine operation. High energy spark discharge systems were better, and could ignite a flame at up to 40% simulated EGR, though again the combustion rates were slow relative to that required for stable engine performance. The most effective systems for stable combustion at high EGR rates were systems which created a large effective flame kernel and/or a long kernel lifetime, such as a torch-style prechamber spark plug or a corona discharge igniter. These results suggest that achieving good engine performance with high EGR rates will require changes to the ignition system of an SI engine to produce a more robust flame kernel.
Technical Paper
2014-10-13
Loic Francqueville, Jean-Baptiste Michel
Abstract EGR dilution is a promising way to improve fuel economy of Spark-Ignited (SI) gasoline engines. In particular, at high load, it is very efficient in mitigating knock at low speed and to decrease exhaust temperature at high speed so that fuel enrichment can be avoided. The objective of this paper is to better understand the governing mechanisms implied in EGR-diluted SI combustion at high load. For this purpose, measurements were performed on a modern, single-cylinder GDI engine (high tumble value, multi-hole injector, central position). In addition 0-D and 1-D Chemkin simulations (reactors and flames) were used to complete the engine tests so as to gain a better understanding of the physical mechanisms. EGR benefits were confirmed and characterized at 19 bar IMEP: net ISFC could be reduced by 17% at 1200rpm and by 6% at 5000rpm. At low speed, knock mitigation was the main effect, improving the cycle efficiency by a better combustion phasing. At high speed, stoichiometric operation could be achieved, avoiding fuel-costly enrichment.
Technical Paper
2014-10-13
Karel Steurs, Christopher Blomberg, Konstantinos Boulouchos
Abstract 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. In order to study knock in a systematic way, spark angle sweeps with ethanol and iso-octane have been carried out on single cylinder spark ignition engine with variable intake temperatures at wide open throttle and stoichiometric premixed fuel/air mixtures. Much earlier and stronger knock can be observed for iso-octane compared to ethanol at otherwise same engine operating conditions due to the cooling effect and higher octane number of ethanol, leading to different cycle-to-cycle variation behavior. Detailed chemical kinetic mechanisms are used to compute ignition delay times at conditions relevant to the measurements and are compared to empirical correlations available in literature. The different correlations are used in a knock model approach and are tested against the measurement data. The importance of using accurate ignition delay time expressions in predicting the correct timing for the onset of knock is illustrated for both ethanol and iso-octane.
Technical Paper
2014-10-13
Ahmad Khalfan, Hu Li, Gordon Andrews
Abstract The tailpipe exhaust emissions were measured using a EURO4 emissions compliant SI car equipped with on-board measurement systems such as a FTIR system for gaseous emission, a differential GPS for velocity, altitude and position, thermal couples for temperatures, and a MAX fuel meter for transient fuel consumption. Various nitrogen species emissions (NO, NO2, NOx, NH3, HCN and N2O) were measured at 0.5 Hz. The tests were designed and employed using two real world driving cycles/routes representing a typical urban road network located in a densely populated area and main crowded road. Journeys at various times of the day were conducted to investigate traffic conditions impacts such as traffic and pedestrian lights, road congestion, grade and turning on emissions, engine thermal efficiency and fuel consumption. The time aligned vehicle moving parameters with Nitrogen pollutant emission data and fuel consumption enabled the micro-analysis of correlations between these parameters. The average data for journeys such as emissions, thermal efficiency and fuel consumption were presented, though this paper is focused on nitrogen compounds.
Technical Paper
2014-10-13
He Changming, Xu Sichuan
The in-cylinder tumble intensity of GDI engine is crucial to combustion stability and thermal efficiency, required to be different for the different operation conditions. A new variable tumble system (VTS) applied to GDI engine was introduced to meet tumble ratio requirements in various situations. The transient gas exchange of four combustion systems all were investigated during both intake and compression strokes based on CFD simulation, namely (1) Case 1-Intake port B (with flap valve)/Spherical piston crown; (2) Case 2-Intake port B (without flap valve)/Spherical piston crown; (3) Case 3- Intake port A/Spherical piston crown; (4) Case 4-Intake port A/Dented piston crown. The simulated results of dynamic tumble ratio showed that during the whole intake process the dynamic tumble ratio of Case1 was obviously higher than other Cases with the same boundary conditions, and the maximum value was about 5∼6 times higher. The crank angle range, in which the strong tumble motion fully developed, was merely about 70°CA, roughly from 410°CA to 480°CA.
Technical Paper
2014-10-13
Ben G. Moxey, Alasdair Cairns, Hua Zhao
The work was concerned with experimental study of the turbulent flame development process of ethanol fuels in an optically accessed spark ignition research engine. The fuels were evaluated in a single cylinder engine equipped with full-bore overhead optical access and operated at typical stoichiometric part-load conditions. High-speed natural light (or chemiluminescence) imaging and simultaneous in-cylinder pressure data measurement and analysis were used to understand the fundamental influence of both low and high ethanol content on turbulent flame propagation and subsequent mass burning. Causes for the difference in cyclic variations were evaluated in detail, with comparisons made to existing burning velocity correlations where available. Overall, it was concluded that the faster burning exhibited with pure ethanol fuel was the result of marginally higher initial laminar-like burning providing a “head start” to the turbulent flame development process, with the turbulent spectrum more quickly encroached leading to reduced bulk flame distortion and faster in-cylinder pressure development.
Technical Paper
2014-10-13
Ajabofu Augoye, Pavlos Aleiferis
International obligations to reduce CO2 emissions, as well as national requirements to strengthen security of fuel supply present the need for diversification towards use of sustainable reduced-carbon fuels such as alcohols. Of these alcohols, ethanol is currently the preferred option with superior octane rating and heat of evaporation compared to gasoline. Ethanol is also already used as a component in pump-grade gasoline of 5-10% per volume in many countries where specifications traditionally dictate the use of anhydrous ethanol (less than 1% water per volume) for such type of blending. This possesses certain challenges since ethanol production typically gives a final product of ethanol purity of about 95.5% per volume with the rest being largely water. Additionally, at higher than this ethanol purity level, ethanol and water exit as an azeotropic mixture. This requires a cost intensive method to further reduce the water content in the mixture to less than 4%. Considering this economics, interest in the use of hydrous ethanol as automobile fuel is rising.
Technical Paper
2014-10-13
Lukasz Grabowski
In this study, the effect of the gas injector distance from an inlet valve on the combustion process under varied of injection timing in an LPG fuelled spark ignition engine was investigated. The test were performed at an engine test stand, where operating conditions for engine work such as crankshaft rotational speed, inlet manifold pressure and coolant temperature were maintained stable. The experiment was carried out on an indirect injection spark ignition engine under partial load and at the constant speed. To perform the experiments, holes in the inlet pipes were made, for four variants of injection nozzle distance from the combustion chamber into which 4 mm diameter nozzles were successively tested. Each distance was measured along the symmetry axis of the inlet port, which represents a real path of the fuel-air mixture. The OPTRAND fibre optic sensor with an ignition adapter was used to measure cylinder pressure. The results show that the engine performance is affected more by the injector distance from the inlet valve than by varied LPG injection timing.
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
Mitsuaki Ohtomo, Hiroshi Miyagawa, Makoto Koike, Nozomi Yokoo, Koichi Nakata
This paper presents the effects of a lubricant oil droplet on start of combustion of fuel-air mixture. Lubricant oil is thought to be a major source of stochastic pre-ignitions in some form in highly boosted spark ignition engines. However, the phenomena has not yet been fully understood because an unpredictable occurrences as well as complexity of mixture and thermodynamical conditions in engine cylinder chamber such as temperature distribution, residual gas and deposit makes its analysis hard. In this study, a suspended isolate oil droplet in a combustion cylinder was picked up as a contaminant to simplify the phenomena. The condition that a single oil droplet ignites earlier than fuel-air mixture was investigated. Test was conducted by using a rapid compression and expansion machine so that the mixture condition in cylinder is controlled with accuracy. Droplet diameter, droplet temperature and fuel-air mixture condition such as mixture strength or octane number of fuel were chosen as parameters.
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