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Event
2014-10-22
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
2014-10-22
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 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
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
2014-10-20
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
Shuonan Xu, David Anderson, Amrit Singh, Mark Hoffman, Robert Prucka, Zoran Filipi
The looming shortage of crude oil provides impetus for engineers to use alternative gaseous fuels in existing engines. Dual-fuel natural gas engines preserve diesel thermal efficiencies and reduce fuel cost without imposing consumer range anxiety. Increased complexity poses several challenges, including the transient response of an engine with direct injection of diesel fuel and injection of Compressed Natural Gas (CNG) upstream of the intake manifold. A 1-D simulation model of a Cummins ISX heavy duty, dual-fuel, natural gas-diesel engine modeled in the GT-Power environment is developed to study and improve transient response. The simulated VGT behavior, intake and exhaust geometry, valve timings and injector models are validated through experimental results. A triple Wiebe combustion model is applied to characterize experimental combustion results for both diesel and dual-fuel operation. The ignition delay and injection timing are determined through an iterative calculation based on Start of Combustion (SOC) and a predictive ignition delay correlation.
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
A.F. Khan, A.A. Burluka, Dave OudeNijeweme, Jens Neumeister, John Mitcalf, Paul Freeland
A holistic modelling approach has been employed to predict combustion, cyclic variability and knock propensity of a high power density SI engine fuelled with gasoline. A quasi-dimensional, thermodynamic combustion modelling approach has been coupled with realistic chemical kinetics modelling of autoignition using reduced mechanisms for gasoline surrogates. The quasi-dimensional approach has been found to allow a fast and appreciably accurate prediction of the effects of operating conditions on the engine performance. It has also provided an insight in to the stability of the turbulent flame as the engine load and speed is varied. The cyclic variability was modelled by perturbing the in-cylinder turbulence and charge composition according to a Gaussian distribution. Its coupling with autoignition modelling allowed to elucidate the effects of operating conditions such as spark-timing and charge temperature on the autoignition onset. In this approach, the autoignition propensity has been predicted for the entire spectrum of cyclic variations in cylinder pressure.
Technical Paper
2014-10-13
Tapio Pohjalainen, Martti Larmi
This study presents a novel crank mechanism which enables easy and fast compression ratio adjustment. The novel crank mechanism and piston travel is explained and highlighted. The basic idea is to have an eccentric crank pin. The eccentricity is easily adjustable. The first full scale engine demonstration test runs were made in Oulu University engine laboratory. The first test are explained. The first demonstration version is modified from an existing commercial SI engine. A GT-Power simulation model of the engine is made. The benefits of the new crank mechanism are demonstrated by the help of the simulation model. The new mechanism offers great possibilities for ex. to increase the part load performance in SI engines or make the engine adjustable for different fuels with best possible efficiency.
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
Yuan Fang'en
Gasoline engine downsizing is firmly established as one of the main technologies for achieving fuel consumption and CO2 reduction targets, with increasing degrees of downsizing being applied in the market place. With advanced downsizing concepts a fuel consumption reduction of 30 % can be achieved. Gasoline Direct Injection (GDI), compared to port fuel injection, allows an increase of the compression ratio by approximately one unit. The main benefits of the spray-guided GDI combustion system are largely possible due to the injector location next to the spark plug. This allows more accurate air fuel mixture control within the combustion chamber and at the spark plug through the variation of injection timing. Further benefits are achievable when multiple injections are used. Spray-guided combustion systems can be used with both solenoid multi-hole and outward opening piezo injectors. Thus, the knock limit at full load can be improved, and it is also an enabler to run stratified lean. Based on that, this article investigated the effect of injection parameter on spray and combustion.
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
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, both with varying levels of EGR. The EGR tolerance of the systems was determined, and it was found that ignition systems which can deliver their energy over a wide spatial area and a long temporal duration provided the best combustion performance. This finding helps to define the ignition system requirements for high-EGR SI engine applications.
Technical Paper
2014-10-13
Shunichi Kubota, Kotaro Tanaka, Mitsuru Konno
An improvement of knocking is indispensable to a fuel consumption improvement and thermal efficiency improvement of a spark-ignition engine. Combustion stability by reducing cycle-to-cycle variations (CCV) and quick completion of combustion by controlling the air-fuel mixture, residual gas, and turbulence is important for the improvement of knocking. It is reported that the variations of the air-fuel mixture distribution and ignition position are correlated in combustion variation of CCV. On the other hand, although three-dimensional simulation using Reynolds Averaged Navier-Stokes Simulation (RANS) for a part of these analyses is utilized widely, the analyses of CCV complicated. Especially, considering of the engine specifications in the short period is difficult in an early phase of development. Therefore, the purpose of this study is to analyze about combustion variations occurred by the air-fuel mixture distribution and ignition using RANS. In order to analyze these, the in-cylinder pressure and the air-fuel mixture concentration (A/F) near the spark plug were measured under CCV.
Technical Paper
2014-10-13
Oliver P. Taylor, Richard Pearson, Richard Stone, Phil Carden, Helen Ballard
Most major regional automotive markets have stringent legislative targets for vehicle greenhouse gas emissions or fuel economy enforced by fiscal penalties. Large improvements in vehicle efficiency on mandated test cycles have already taken place in some markets through the widespread adoption of technologies such as downsizing or dieselization. There is now increased focus on approaches which give smaller but significant incremental efficiency benefits such as reducing parasitic losses due to engine friction. Fuel economy improvements which achieve this through the development of advanced engine lubricants are very attractive to vehicle manufacturers due to their favorable cost-benefit ratio. For an engine with components which operate predominantly in the hydrodynamic lubrication regime, the most significant lubricant parameter which can be changed to improve the tribological performance of the system is the lubricant viscosity. Low viscosity lubricants are increasingly being specified by vehicle manufacturers who are now more frequently working directly with the lubricant supplier to design fluids specific to their requirements.
Technical Paper
2014-10-13
Pawel Magryta
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
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
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
Werner E. Holly, Thomas Lauer, Henrik Schuemie, Shinsuke Murakami
Future emissions from maritime traffic will be limited by the IMO III regulation, which means further reductions of nitric oxide and soot emissions. Therefore, large gas engines become a genuine alternative to diesel engines operated with HFO. A combustion process with high air/fuel-ratio enables low combustion temperatures and therefore low wall heat losses and nitric oxide raw emissions. On the other hand, the cycle-to-cycle variations increase. Numerical methods can support the development process to define operating points with highest efficiences and emissions that meet the regulation limits. However, these models must be able to describe the thermodynamics of the combustion process and the kinetically controled knocking combustion. In this paper, an approach with a stochastic reactor model is presented that includes the detailed chemistry of the investigated fuel gas. Due to the fact that the knocking combustion and the emissions are closely related to the fast and slow burning cycles, an empirical relation of the cycle-to-cycle variations was implemented.
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
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
Qiang Zhang, Jiangping Tian, Xiangyu Meng, Yicong Wang, Wuqiang Long
A novel combustion system called JCCI (Jet Controlled Compression Ignition) is investigated to directly control the combustion phasing of diesel premixed compression ignition. 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. Then detailed combustion characteristics were analyzed based on one of simulation results. The simulation results showed that the reacting active radical species issued from ignition chamber played an important role on the onset of combustion in JCCI system. The diesel pre-mixture of main combustion chamber was ignited rapidly by the combustion products issued from ignition chamber, so that precise ignition phasing control for diesel pre-mixture would be realized. Consequently, the experiments of spark timing sweep were conducted to verify the above deduction. The results showed the good linearity of spark timing in ignition chamber versus CA10 and CA50, which validated the capability of direct combustion phasing control in diesel premixed combustion.
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
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
Loic Francqueville, Jean-Baptiste Michel
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 to mitigate 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 have been 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) have been 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: 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
Yasuhiro Hikita, Masahiro Kawahara, Naoto Noguchi
Oil supplying device for each cam of a camshaft is called 'Cam-Shower'. Newdesign of cam-shower has been developed. The developed design can reduce oil flow of a cam-shower, so that discharge rate of oil pump can be reduced and its driving torque gets lower. Its effect on low fuel consumption is estimated at 0.1% in JC08 mode testing of Japan. At the beginning of developing new cam-shower, optimal oil flow to each camwas verified by visualizing with transparent cylinder head cover of valve train. Conventional cam-shower is simple straight pipe shape with several same size outlets to each cam. Oil from cylinder head is supplied in the middle of cam-shower pipe. The oil flow of outlet near supplied point is large amount, and outlet far from supplied point is small. But this conventional design of cam-shower satisfies lubricating performance for each cam because lubrication condition is adjusted to the far outlet. Therefore the excess amount of oil flow can afford to reduce. It is found thatsum of excess oil flow reaches 90% of total volume.
Technical Paper
2014-10-13
Kang Xu, Hui Xie, Tao Chen, Minggang Wan, Hua Zhao
Abstract: SCHC (SI-CAI hybrid combustion), also named as spark-assisted HCCI, has been proved to be an effective method to stabilize combustion and extend the operation range. The combustion is initiated by the spark discharge followed by a propagation of flame front until the auto-ignition of end-gas. Spark ignition and the spark timing can be used to control the combustion event. The goal of this research is to study the effect of flame propagation on the auto-ignition timing in SCH combustion by means of chemiluminescence imaging and heat release analysis on an optical engine. In consideration of the discrepancy of heat release rate between the flame propagation and the auto-ignition stage, the curve of heat release rate in SCH combustion shows significant asymmetry. Consequently, the auto-ignition timing instead of CA50 (crank angle degree of 50% burnt mass) was used to represent the combustion phasing. Chemiluminescence imaging of the SCH combustion reveals the cyclic variation characteristics of the early flame development.
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
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.
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