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Video

Parameter Identification of a Power Loss Model for Vehicle Transmissions Based on Sensitivity Analysis

2020-09-17
As the transmission design directly impacts drive unite operation and power flow to the driveline, the transmission power loss is a critical target in the drivetrain development. The demand of more precise and more efficient power loss prediction has therefore increased significantly, which highlights the need of new methodologies in order to optimize the power loss model for vehicle transmissions. The possible power losses that exist in the power flow path, are gear mesh losses, gear churning losses, gear windage losses, bearing losses, synchronizer losses and sealing losses. Thanks to the decades of research, analytical models are available for the prediction of these component losses, which could deliver power loss distributions and overall efficiency maps of complex transmissions.The aim of this paper is to introduce a methodology to improve the accuracy of a chosen power loss model on a system level.
Video

A Machine Learning Modeling Approach for High Pressure Direct Injection Dual Fuel Compressed Natural Gas Engines

2020-09-17
The emissions and efficiency of modern internal combustion engines need to be improved to reduce their environmental impact. Many strategies to address this (e.g., alternative fuels, exhaust gas aftertreatment, novel injection systems, etc.) require engine calibrations to be modified, involving extensive experimental data collection. A new approach to modeling and data collection is proposed to expedite the development of these new technologies and to reduce their upfront cost. This work evaluates a Gaussian Process Regression, Artificial Neural Network and Bayesian Optimization based strategy for the efficient development of machine learning models, intended for engine optimization and calibration. The objective of this method is to minimize the size of the required experimental data set and reduce the associated data collection cost for engine modeling.
Video

Providing of Sliding Bearings Reliability of Transmissions Gear Wheels of Transport Cars by Optimization of Assembly Tolerances

2020-09-17
In the design of gearboxes and transfer boxes of heavy-duty vehicle`s transmissions, sliding bearings are often used as supports for gear wheels.Analysis of the results of statistical processing of gearbox parts failures and transfer boxes of wheeled tractors with a pulling force of 30 kN indicates the need to improve the reliability of the sliding bearings of the gear wheels. Such plain bearings ensure free rotation of the gear wheels in case of the torque transmission absence, and when locked by a clutch, the radial load of the gear wheel is sensed, while operating in the slipping rolling mode. Such units are poorly understood and in the technical literature sources there are no recommendations for their engineering, which often leads to errors when selecting operation gaps and press fitted in gear wheels.The manufacturers of the transmissions assemblies replaced the plain bearings, which in this case are made of metal-ceramic bushes, for roller bearings.
Video

Study on the Pre-Chamber Fueling Ratio Effect on the Main Chamber Combustion Using Simultaneous PLIF and OH* Chemiluminescence Imaging

2020-09-17
Pre-chamber combustion (PCC) enables leaner air-fuel ratio operation by improving its ignitability and extending flammability limit, and consequently, offers better thermal efficiency than conventional spark ignition operation. The geometry and fuel concentration of the pre-chamber (PC) is one of the major parameters that affect overall performance. To understand the dynamics of the PCC in practical engine conditions, this study focused on (i) correlation of the events in the main chamber (MC) with the measured in-cylinder pressure traces and, (ii) the effect of fuel concentration on the MC combustion characteristics using laser diagnostics. We performed simultaneous acetone planar laser-induced fluorescence (PLIF) from the side, and OH* chemiluminescence imaging from the bottom in a heavy-duty optical engine. Two different PC Fueling Ratios (PCFR, the ratio of PC fuel to the total fuel), 7%, and 13%, were investigated. The ?negative?
Video

Research of Fuel Components to Expand Lean-Limit in Super Lean Burn Condition (Part II)

2020-09-17
Thermal efficiency can be improved with a super lean-burn. In a super lean-burn engine, combustion takes place at lower temperatures, meaning lower energy losses and much greater thermal efficiency. In Part I (presented at PF&L 2019) [1], we studied the effects of various fuels on the lean limit in super lean-burn conditions. We found that the lean limit could be greatly extended and thermal efficiency improved with the right combination of engine technology and fuel technology. We also found that the lean limit closely linked to the duration from start-of-spark discharge to CA10, and that substances which shorten this duration extends the lean limit. In this study, we evaluated the effects of hydrocarbons closer in composition to commercial gasoline on the lean limit and found that at the specific components, the lean limit could be much higher than that with commercial gasoline. We also studied the lean limit extension mechanism by focusing on autoignition.
Video

Large Eddy Simulation Study of Biofuel Injection in an Optical Direct Injection Engine.

2020-09-17
The air-fuel mixture formation in an optical direct-injection internal combustion engine is investigated by numerical simulations for the two biofuels Ethanol and 2-Butanone. The gas phase in the internal combustion (IC) engine is predicted by a large-eddy simulation, in which the fuel phase is determined by a spray model based on Lagrangian particle tracking. A hollow-cone injector is used for which the primary breakup is modeled by a series of small full-cone injections, while the Rosin-Rammler initial droplet size distribution is used. The secondary spray break-up is modeled by the Kelvin-Helmholtz-Rayleigh-Taylor (KHRT) model, and the evaporation of the fuel is determined by the Bellan-Harstad model. The gas phase simulation is based on a finite-volume method formulated for hierarchical Cartesian grids, in which the immersed moving boundaries are resolved using a multiple level-set/cut-cell approach.
Video

Cycle-resolved Evaluation of Directly Injected Methane using a High-Speed Laser-induced Fluorescence Measurement System

2020-09-17
The usage of alternative fuels inside internal combustion engines (ICE), is one promising approach to meet the higher requirements concerning the efficiency and emission of modern combustion systems. The injection and mixture formation of such fuels has a major impact on the subsequent combustion as well as the formation of pollutants. To rate the influence and to gain a better understanding of those new alternatives a basic understanding of these dominant processes is mandatory. The principle of laser-induced fluorescence (LIF) is a well-known method to display and evaluate fuel distributions inside combustion chambers. A suiting online calibration routine allows the visualization of air-fuel equivalence ratio (λ) two-dimensionally during different operation modes. As cyclic variations can become a more critical issue while using alternative fuels, cycle- resolved test series become more and more important.
Video

Impact of Combustion Engine Operating Conditions on Energy Flow in Hybrid Drives in RDC Tests

2020-09-17
Energy flow in vehicles with hybrid propulsion systems depends primarily on the drive system design. The full hybrid propulsion system (series-parallel) enables differentiated energy flow management using different drive system operating conditions and energy recovery methods. The article attempts to estimate the energy differences resulting from this type of a system operating in two different modes: mode D - normal driving and mode B - forcing partial use of engine braking. Using these two driving modes in the real drive test, the energy flow characteristics of the vehicle were determined. Different operating conditions of the internal combustion engine and drive system in both modes allowed for the energy consumption during driving tests to be assessed.
Video

Effect of Renewable Fuel Blends on PN and SPN Emissions in a GDI Engine

2020-09-17
To characterize the effects of renewable fuels on particulate emissions from GDI engines, engine experiments were conducted using EN228-compliant gasoline fuel blends containing no oxygenates, 10% ethanol (EtOH), or 22% ethyl tert-butyl ether (ETBE). The experiments were conducted in a single cylinder GDI engine using a 6-hole fuel injector operated at 200 bar injection pressure. Both PN in raw exhaust and solid PN (SPN) were measured at two load points and various start of injection (SOI) timings.
Video

Complex Assessment of Fuel Efficiency and Diesel Exhaust Toxicity

2020-09-17
Problems of reducing emissions of harmful substances and fuel consumption of the engine are interrelated, since they are mainly determined by the work process. Measures aimed to reducing fuel consumption cause changes, often upwards, toxic compound formation. The fuel and environmental criterion is proposed taking into account the engine operating conditions for a reasonable choice of technical solutions for the comprehensive improvement of fuel economy and toxic level indicators of the exhaust gases. This criterion allows assessing the effectiveness of solutions to improve combustion efficiency, the use of alternative fuels, exhaust gas aftertreatment systems, and other measures.
Video

Impact of Extended Expansion Stroke on Spark Ignition Engine Operation Indicators with Multiple Linkage System

2020-09-17
Increasing the efficiency of an internal combustion engine is possible thanks to the use of an extended expansion stroke relative to the suction stroke. This solution was first patented by James Atkinson in the construction of an internal combustion engine in the XIX century. The article presents a solution using the principle of extended expansion stroke. In the design of Szymkowiak's proprietary engine, a conceptual crank-piston system was used with additional elements enabling the Atkinson cycle to be obtained. A 3D model was created based on which forces acting in the system were tested. The generated piston path profile allowed to characterize its movement. A mobile mesh of the combustion chamber was created, thanks to this a detailed CFD simulation was performed in the AVL Fire software. An important criterion was the assumption of adiabatic characteristics of processes during the combustion.
Video

Analysis of Gasoline Surrogate Combustion Chemistry with a Skeletal Mechanism

2020-09-17
Knocking combustion is a major obstacle towards engine downsizing and boosting?popular techniques towards meeting the increasingly stringent emission standards of SI engines. The commercially available gasoline is a mixture of many chemical compounds like paraffins, isoparaffins, olefins and aromatics⁠. Therefore, the modeling of its combustion process is a difficult task. Additionally, the blends of certain compounds exhibit non-linear behavior in comparison to the pure components in terms of knock resistance. These facts require further analysis from the perspective of combustion chemistry. The present work analyses the effects of blending ethanol to FACE-C gasoline. A range of pressures, temperatures, and equivalence ratios has been considered for this purpose. The open source softwares Cantera version 2.4.0 and OpenSMOKE++ Suite have been used for the simulations.
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Measurement and Evaluation of the Optical Properties of Diesel Particulate Emissions

2020-09-17
Improvements in engine technology have led to drastic reductions in the mass emissions of particulate from diesel engines. Research is now focused on the characterisation of the particulate matter and its potential impacts as a climate forcing agent. Much is known about the role of greenhouse gases (GHG) in atmospheric chemistry, however atmospheric black carbon also makes an important contribution to the warming of the global atmosphere. This work investigates the optical properties of particulates which are shown to be affected by the proportion of black carbon linked to mixing state. Black carbon (BC) emitted from engines, and other combustion systems, is known to absorb solar radiation in the atmosphere and have a strong warming effect on climate, particularly on local scales. However, strong uncertainties arise because the per-mass light absorption is strongly influenced by other materials, such as semi-volatile organics, co-emitted with the BC (known as the �coating�).
Video

Methodology and Results of Testing an Impact of F-34 Fuel on the Engine Reliability

2020-09-17
An application of the new kind of the fuel for the diesel engine requires to conduct the qualification tests of the engines powered by this his fuel which allow assessing an impact of fuel on the engine reliability. Such a qualification test of the piston and turbine engines of the aircraft stationed on the ground and land vehicles is described in the NATO standardisation agreement (STANAG) 4195 as the AEP-5 test. The methodology and selected results of the qualification tests of the SW-680 turbocharged multi-purpose diesel engine fueled with F-34 fuel have been presented in this paper.A dynamometric stand with the SW-680 engine has been described. Based on the preliminary results of the investigation it has been found that a change in a type of the fuel from IZ-40 diesel fuel into F-34 kerosene-type one has reduced a maximum engine torque by about 4%. This has been primarily due to a lower fuel density of F-34 by about 3%.
Video

Optimization of Piston Bowl Geometry for a Low Emission Heavy-Duty Diesel Engine

2020-09-17
A computational fluid dynamics (CFD) guided design optimization was conducted for the piston bowl geometry for a heavy-duty diesel engine. The optimization goal was to minimize engine-out NOx emissions without sacrificing engine peak power and thermal efficiency. The CFD model was validated with experiments and the combustion system optimization was conducted under three selected operating conditions representing low speed, maximum torque, and rated power. A hundred piston bowl shapes were generated, of which 32 shapes with 3 spray angles for each shape were numerically analyzed and one optimized design of piston bowl geometry with spray angle was selected. On average, the optimized combustion system decreased nitrogen oxide (NOx) emissions by 17% and soot emissions by 41% without compromising maximum engine power and fuel economy.
Video

The System for Adding Hydrogen-containing Gas to the Air Charge of the Spark Ignition Engine Using a Thermoelectric Generator

2020-09-17
The article is devoted to the study of the efficiency of the system that provides the production of hydrogen-containing gas using a thermoelectric generator and the addition of this gas to the air charge of the spark ignition engine to improve its indicated, effective and environmental performance. The thermoelectric generator is installed in the engine exhaust system and provides the conversion of the exhaust gas thermal energy into electrical energy to power the generator of the hydrogen-containing gas. The results of experimental studies of indicated, effective and environmental performance of the engine with the hydrogen-containing gas added in a wide range of operating modes are provided. Vehicle fuel economy and environmental performance with the developed system for adding the hydrogen-containing gas are forecasted using a mathematical model of the car motion in the driving cycle.
Video

Narrow-throat Pre-chamber Combustion with Ethanol, a Comparison with Methane

2020-09-17
With increasingly stringent emissions regulations, the use of pre-chamber combustion systems is gaining popularity in Internal Combustion Engines (ICE). The advantages of pre-chambers are well established, such as improving fuel economy by increasing the lean limit and reducing emissions, particularly NOX. In pre-chamber combustion, flame jets shoot out from the pre-chamber orifices into the main chamber, generating several ignition points that promote a rapid burn rate of the lean mixture (excess-air ratio (λ) >1) in the main chamber. This work studies the effects of using two different fuels in the main chamber and assesses the lean limit, the combustion efficiency (ηc), and the emissions of a single-cylinder heavy-duty engine equipped with a narrow-throat active pre-chamber. Ethanol (C2H5OH) was tested in the main chamber while keeping the pre-chamber fueled with methane (CH4), and the results were then compared to using methane as the sole fuel.
Video

Effects of Ignition Control on Combustion Process Non-Repeatability in an Aircraft Radial Piston Engine

2020-09-17
The ignition method significantly affects the combustion process in piston aircraft engines. This paper presents the results of bench tests of two variants of the radial piston aircraft engine: equipped with a standard magneto system and an electronic dual ignition system. The engine was tested in steady states for operating points defined by rotational speed and load. Their values corresponded to a load ranging from 50% of nominal power to take-off power. The ignition advance angle was constant for the engine equipped with ignition magnetos, while for the second engine variant it was determined by the developed algorithm introduced to the electronic ignition system control unit. The analysis of the combustion process was based on pressure measurements in one cylinder.
Video

Effect of Jet-Jet Angle on Combustion Process of Diesel Spray in an RCEM

2020-09-17
The effects of jet-jet angle on the combustion process were investigated in an optical accessible rapid compression and expansion machine (RCEM) under various injection conditions and intake oxygen concentrations. The RCEM was equipped with an asymmetric six-hole nozzle having jet-jet angles of 30? and 45?. High-speed OH* chemiluminescence imaging and direct photo imaging using the Mie scattering method captured the transient evolution of the spray flame, characterized by lift-off length and liquid length. The RCEM operated at 1200 rpm. The injection timing was -5?ATDC, and the in-cylinder pressure and temperature were 6.1 MPa and 780 K at the injection timing, respectively, which achieved a short ignition delay. The effects of injection pressure, nozzle hole diameter, and oxygen concentration were investigated. The results show that the liquid and lift-off length of the jet-jet angle of 30? were shorter than those of the jet-jet angle of 45?
Video

Effect of Initial Fuel Temperature on Spray Characteristics of Multicomponent Fuel

2020-09-17
Fuel design concept has been proposed for low emission and combustion control in engine systems. In this concept, the multicomponent fuels, which are mixed with a high volatility fuel (gasoline or gaseous fuel components) and a low volatility fuel (gas oil or fuel oil components), are used for artificial control of fuel properties. In addition, these multicomponent fuels can easily lead to flash boiling which promote atomization and vaporization in the spray process. In order to understand atomization and vaporization process of multicomponent fuels in detail, the model for flash boiling spray of multicomponent fuel have been constructed and implemented into KIVA3V rel.2. This model considers the detailed physical properties and evaporation process of multicomponent fuel and the bubble nucleation, growth and disruption in a nozzle orifice and injected fuel droplets.
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