Criteria

Text:
Display:

Results

Viewing 1 to 30 of 6730
2017-09-04
Technical Paper
2017-24-0023
Karim Gharaibeh, Aaron W. Costall
Internal combustion engines are routinely developed using 1D engine simulation tools. A well-known limitation is the accuracy of the turbocharger compressor and turbine sub-models, which generally rely on hot gas bench-measured maps to characterize their performance. Such discrete map data is inherently too sparse to be used directly in simulation, and so a pre-processing algorithm interpolates and extrapolates the data to generate a wider and more densely populated map. Methods used for compressor map interpolation vary. They may be mathematical or physical in nature, but there is no unified approach, except for the fact that they often operate on input map data in SAE standard format. Indeed, for decades it has been common practice for turbocharger suppliers to share performance data with their engine OEM customers in this form.
2017-09-04
Technical Paper
2017-24-0073
Carlo Beatrice, Giacomo Belgiorno, Gabriele Di Blasio, Ezio Mancaruso, Luigi Sequino, Bianca Maria Vaglieco
Technologies for direct injection of fuel in compression ignition engines are in continuous development in order to get an increasingly high injection pressure. One of the most investigated component of this system is the injector; in particular, main attention is given to the nozzles characteristics as diameter, number, angle, internal shape. The reduction of nozzle hole diameter seems the simplest way to increase the fuel velocity and to promote the atomization process. On the other hand, the number of the holes must increase to keep the desired mass flow. On this basis, a new logic has been applied for the development of the next generation of injectors. The tendency to increase the nozzle number and to reduce the diameter has led to the replacement of the nozzle with a circular plate that moves vertically. The plate motion allows to obtain a cylindrical surface for the delivery of the fuel on 360° degrees; while the plate lift is calibrated to obtain the desired fuel mass flow.
2017-09-04
Technical Paper
2017-24-0101
Pedro Marti-Aldaravi, Kaushik Saha, Jaime Gimeno, Sibendu Som
Actual combustion strategies in internal combustion engines rely on fast and accurate injection systems to be successful. One of the injector designs that has shown good performance over the past years is the direct-acting piezoelectric. This system allows precise control of the injector needle position and so the injected mass flow rate. Therefore, understanding how nozzle flow characteristics change as function of needle dynamics helps to choose the best lift law in terms of delivered fuel for a determined combustion strategy. Computational Fluid Dynamics is a useful tool for this task. In this work, nozzle flow of a prototype direct-acting piezoelectric has been simulated by using CONVERGE v2.3.10. Unsteady Reynolds-Averaged Navier-Stokes approach is used to take into account the turbulence. Simulations are able to properly capture the relationship between instantaneous partial needle lifts and the corresponding rate of injection.
2017-09-04
Technical Paper
2017-24-0108
Alessandro Montanaro, Marianna Migliaccio, Luigi Allocca, Carlo Beatrice, Valentina Fraioli, Roberto Ianniello
The combustion efficiency in modern diesel engines strictly depends on the quality of the air-fuel mixing and, in turn, the quality of spray atomization process. The air-fuel mixing is strongly influenced by the injection pressure, the geometry of the nozzle and the hydraulic characteristics of the injector. In this context, outward-opening piezoelectric injectors are gaining popularity as a high efficient device because of its precise control of the fuel injected. In the present paper, a new concept of open nozzle spray was investigated being a possible application for diesel engines. The study concerns an experimental and numerical characterization of a spray generated through a prototype high-pressure hollow-cone nozzle (HCN).
2017-09-04
Technical Paper
2017-24-0005
Guillaume Goumy, Pascal Chesse, Nicolas Perrot, Rémi Dubouil
Turbocharging has nowadays become a common solution to complete downsizing in the quest for reaching the new polluting emission constraints. Besides to reduce the developing costs and meet the ever tightening regulations, car manufacturer relies more and more on computer simulations. Thus developing an accurate and predictable turbocharger model, functioning on a wide range of engine life cases, is now a requirement. In the current models, compressors and turbines are represented by look-up tables, experimentally measured on a turbocharger test bench, at steady point and high inlet turbine temperature. This method results in limited maps : the compressor choke line depends on the test bench, and a typical turbine iso-speed is limited to a 0.5 ratio range. Put up on an engine, the turbocharger encounters a wider scale of functioning points. using only the present compressor and turbine maps in an engine simulation model no enough.
2017-09-04
Technical Paper
2017-24-0031
Imre Gergely Nagy, Andrea Matrisciano, Harry Lehtiniemi, Fabian Mauss, Andreas Schmid
Large two-stroke marine diesel engines have special injector geometries, which differ substantially from the configurations used in most other Diesel engine applications. One of the major differences is that injector orifices are distributed in a highly non-symmetric fashion that affects the spray morphology. Earlier investigations demonstrated the dependency of the spray morphology on the location of the spray orifice, and therefore on the resulting flow conditions at the nozzle tip. Thus, spray structure is directly affected by the flow structure within the orifice [1]. Following recent LES resolved spray primary breakup studies [2], the present paper focuses on spray secondary breakup modelling of asymmetric spray structures in Euler-Lagrangian framework based on previous droplet distributions of primary breakup. Firstly, the derived droplet distributions are assigned via user coding to RANS 3D-CFD simulation of two nozzle bore geometries having 0.0 and 1.1 mm eccentricity.
2017-09-04
Technical Paper
2017-24-0020
Michele Becciani, Alessandro Bianchini, Matteo Checcucci, Lorenzo Ferrari, Michele De Luca, Luca Marmorini, Andrea Arnone, Giovanni Ferrara
The onset of aerodynamic instabilities towards the left margin of the operating curve represents one of the main limitations for centrifugal compressors for turbocharging applications. Anticipated stall/surge onset is particularly critical at those high boost pressures that are typical of downsizing applications using a turbocharger. Several stabilization techniques have been investigated so far to increase the rangeability of the compressor, without too relevant detriment of its efficiency. One of the most exploited solutions in this sense is represented by the use of upstream axial variable inlet guide vanes (VIGV). In the pre-design phase of a new stage or when selecting - for example - an existing unit from an industrial catalogue, it is however not easy to have a prompt estimation of the attended modifications induced by the VIGV on the performance map of the compressor.
2017-09-04
Technical Paper
2017-24-0111
Heechang Oh, JuHun Lee, Seungkook Han, Chansoo Park, Choongsik Bae, Jungho Lee, In Keun Seo, Sung Jae Kim
In this study, the effect of nozzle tip geometry on nozzle tip wetting and particulate emissions was investigated. Various design concepts of injector nozzle hole were newly developed for this study. Spray and emission characteristics of each concept were discussed with experimental results. The macroscopic spray visualization was carried out in a constant volume chamber to investigate general spray characteristics of each nozzle hole concept. The laser induced fluorescence technique was applied to evaluate fuel wetting characteristics on the nozzle tip. The vehicle test and emissions measurement in chassi dynamo were performed to investigate particulate emission characteristics for various injector nozzle designs. In addition, during a vehicle test, the in-cylinder combustion visualization with the optical fiber sensor (AVL VISIO VOLUME) was conducted to provide a comprehensive understanding of diffusion combustion and wetting behavior.
2017-08-29
Journal Article
2017-01-9001
Hermann Ferschitz, Michael Wannemacher, Otto Bucek, Florian Knöbel, Wolfgang Breitfuß
Abstract RTA Rail Tec Arsenal Fahrzeugversuchsanlage GmbH has focused on the simulation of in-flight icing conditions since 2012. Following the successful implementation of the icing conditions specified in EASA CS-25 Appendix C, it was expected that the facility could also be used to simulate the SLD conditions required by EASA CS-25 Appendix O. This paper sets forth theoretical considerations concerning the selection of suitable nozzles and their operation in the existing facility. The transport of large droplets through the contraction nozzle was simulated using a CFD program. The results then served as a basis for deriving secondary droplet breakup. The validations carried out confirm the theoretical considerations and identify potential limits and open research questions.
2017-07-10
Technical Paper
2017-28-1928
Rajesh Babu Channamaneni, P Kannan, Prasad Padavala
Abstract Engine mounts and mounting brackets play a critical role in determining NVH performance of a vehicle. A lot of work has been done in the area of virtual simulation using FE models to study engine mounting system performance and its impact on vehicle level performance. An overall approach towards engine mounting system validation at vehicle level is also very critical to validate simulation results in a prototype based on which further refinement work will be carried. In this paper a detailed procedure for engine mount and mounting bracket physical validation at vehicle level is presented. Various tests to be performed at vehicle level to quantify engine mount and mounting bracket performance parameters is discussed in detail along with measurement procedures and techniques. Test results are interpreted and its impact on overall performance is also explained.
2017-07-10
Technical Paper
2017-28-1934
Anil Thakur, Md Tauseef Alam, Venkatesh Kumar PS, P D Kulkarni, Senthur Pandian
Abstract Current high rating thermal loaded engines must have super-efficient lubrication system to provide clean oil at appropriate pressure and appropriate lube oil temperature to every part of the engine at all engine RPM speeds and loads. So oil pump not only have to satisfy above parameters but also it should be durable till engine life. Gerotor pumps are internal rotary positive-displacement pumps in which the outer rotor has one tooth more than the inner rotor. The gear profiles have a cycloidal shape. Both are meshed in conjugate to each other. Gerotor takes up engine power through crankshaft and deliver to various engine consumers at required pressure and required time. Over the complete engine rpm speed and loads range, oil pump need to perform efficiently to provide proper functioning of the engine.
2017-07-10
Technical Paper
2017-28-1961
Shishir Sirohi, Saurabh Yadav, B. Ashok, V Ramesh Babu, C Kavitha, K Nantha Gopal
The main objective of the study is to design and analyze casing and supports of a transmission system for an electric vehicle. The system comprises of motors as the power source, constant mesh gear box coupled with limited slip differential as the power transmitting source. The space occupied by the transmission system is a foremost constraint in designing the system. The wear and tear in the system are caused by the gear meshing process and transmission error which lead to failure of the transmission system. This internal excitation also produces a dynamic mesh force, which is transmitted to the casing and mounts through shafts and bearings. In order to overcome such issues in a transmission system, a gear box casing, differential mounts and motor mounts have been designed by the use of CAD-modelling software “SOLIDWORKS”. The designs were imported to FEA software “ANSYS” for carrying out static structural analysis.
2017-07-10
Technical Paper
2017-28-1947
Suresh Kumar Kandreegula, Kamal Rohilla, Naveen Sukumar, Kunal Kamal
Abstract A propeller shaft is a mechanical component of drive train that connects transmission to drive wheels/axle with the goal to transfer rotation and torque. It is used when the direct connection between transmission and drive axle is not possible due to large distance between their respective assigned design spaces. In commercial vehicles especially in heavy duty (GVW/GCW>15 tons) a single piece propeller shaft is seldom used due to its inherent disadvantages and therefore, most if not all, of the setups consists of multiple pieces of propeller shaft which are directly mounted on to frame cross members with the help of mounting brackets. As such the mounting bracket assembly undergoes various dynamic and static loading conditions and should be able to withstand these loads. This paper will focus on the FEA analysis of propeller shaft mounting assembly system.
2017-07-10
Technical Paper
2017-28-1948
John Samuel Kopppula, Thundil Karuppa Raj Rajagopal, Edison Gundabattini
Abstract The present work is concentrated to study the effect of varying inlet pressures on the dynamics of the suction valve obtained from a hermetic reciprocating compressor. The effect of valve functioning on the efficiency of a compressor is highly acceptable. Rather than the delivery valve, the suction valve has a significant impact on the compressor efficiency. The reed valve in a hermetic compressor is a cantilever type arrangement. The valve operates due to the pressure difference between the suction muffler and the cylinder. The numerical analysis which includes Fluid-structure interaction is used in the present study. The flow and structural domain employed in the present study are modelled with Solidworks 15.0. The fluid structure interaction analysis is a combination of ANSYS Fluent and ANSYS structural. These two are coupled with a system coupling in ANSYS Workbench 16.0. The numerical results obtained from the simulation are validated with the experimental data.
2017-06-17
Technical Paper
2017-01-9453
Tobias Hoernig
Within the scope of today’s product development in automotive engineering the aim is to produce more light and solid parts with higher capabilities. On the one hand lightweight materials such as aluminum or magnesium are used, but on the other hand, increased stresses on these components cause higher bolt forces in joining technology. Therefore screws with very high strength rise in importance. At the same time, users need reliable and effective design methods to develop new products at reasonable cost in short time. The bolted joints require a special structural design of the thread engagement in low-strength components. Hence an extension of existing dimensioning of the thread engagement for modern requirements is necessary. In the context of this contribution, this will be addressed in two dimensions: on one hand extreme situations (low strength nut components and high-strength fasteners) are considered.
2017-06-05
Journal Article
2017-01-1909
Joel Bruns, Jason Dreyer
Abstract The application of hydraulic body mounts between a pickup truck frame and cab to reduce freeway hop and smooth road shake has been documented in literature and realized in production vehicles. Previous studies have demonstrated the potential benefits of these devices, often through iterative prototype evaluation. Component dynamic characterization has also shown that these devices exhibit significant dependence to preload and dynamic amplitude; however, analysis of these devices has not addressed these dependences. This paper aims to understand the amplitude and preload dependence on the spectrally-varying properties of a production hydraulic body mount. This double-pumping, three-spring mount construction has a shared compliant element between the two fluid-filled chambers.
2017-06-05
Technical Paper
2017-01-1907
Yang Wang, Yong Xu, Xiao Tan
Abstract The vibration isolation performance of vehicle powertrain mounting system is mostly determined by the three-directional stiffness of each mount block. Because of the manufacturing tolerance and the coupling effect, the stiffness of mounts cannot be maintained stable. The purpose of this study was to find out the way to optimize the stiffness of mounts via the design of experiments (DOE). According to the DOE process, a full factorial design was implemented. The z-direction stiffness of three mount blocks in the mounting system was selected as the three analysis factors. The maximum and the minimum stiffness of each mount block within the manufacturing tolerance were selected as the two levels. The measured vibration of vehicle body under certain loading case was selected as the response factor. After eight times of experiment, the DOE parameters were analyzed with statistical methods.
2017-06-05
Journal Article
2017-01-1772
Yawen Wang, Xuan Li, Guan Qiao, Teik Lim
Abstract The prediction and control of gear vibration and noise has become very important in the design of a quiet, high-quality gearbox systems. The vibratory energy of the gear pair caused by transmission error excitation is transmitted structurally through shaft-bearing-housing assembly and radiates off from exterior housing surface. Most of the previous studies ignore the contribution of components flexibility to the transmission error (TE) and system dynamic responses. In this study, a system level model of axle system with hypoid gear pair is developed, aiming at investigating the effect of the elasticity of the shafts, bearings and housing on TE as well as the contribution of flexible bearings on the dynamic responses. The load distribution results and gear transmission errors are calculated and compared between different assumptions on the boundary conditions.
2017-06-05
Journal Article
2017-01-1776
Mohsen Kolivand, Glen Steyer, Clifford Krieger, Max-Ferdinand Stroh
Abstract Hypoid gears transmission error (TE) is a metric that is usually used to evaluate their NVH performance in component level. The test is usually done at nominal position as well as out of positions where the pinion and gear are moved along their own axis and also along offset direction to evaluate sensitivity of the measured TE to positional errors. Such practice is crucial in practical applications where the gear sets are inevitably exposed to off position conditions due to a) housing machining and building errors, b) deflections of housing, bearings, etc. under load and c) thermal expansions or contractions of housing due to ambient temperature variations. From initial design to development stage, efforts should be made to design the gear sets to be robust enough to all combinations of misalignments emanated from all three mentioned categories.
2017-06-05
Technical Paper
2017-01-1809
Dhanesh Purekar
Abstract Engine noise is one of the significant aspects of product quality for light and medium duty diesel engine market applications. Gear whine is one of those noise issues, which is considered objectionable and impacts the customer’s perception of the product quality. Gear whine could result due to defects in the gear manufacturing process and/or due to inaccurate design of the gear macro and micro geometry. The focus of this technical paper is to discuss gear whine considerations from the production plant perspective. This includes quick overview of the measurement process, test cell environment, noise acceptance criteria considerations. A gear whine case study is presented based on the data collected in the test cell at the engine plant. Gear whine data acquired on current product and next generation of prototype engines is analyzed and presented. This paper concludes by highlighting the lessons learned from the case study.
2017-06-05
Technical Paper
2017-01-1820
Martin Sopouch, Josip Hozmec, Alessandro Cadario
Abstract This paper presents a simulation environment and methodology for noise and vibration analyses of a driven rear axle in a bus application, with particular focus on medium to high frequency range (400 Hz to 3 kHz). The workflow demonstrates structure borne noise and sound radiation analyses. The fully flexible Multi-Body Dynamics (MBD) model - serving to cover the actual mechanical excitation mechanisms and the structural domain - includes geometrical contacts of hypoid gear in the central gear and planetary gear integrated at hubs, considering non-linear meshing stiffness. Contribution of aforementioned gear stages, as well as the propeller shaft universal joint at the pinion axle, on overall axle noise levels is investigated by means of sensitivity analysis. Based on the surface velocities computed at the vibrating axle-housing structure the Wave Based Technique (WBT) is employed to solve the airborne noise problem and predict the radiated sound.
2017-06-05
Technical Paper
2017-01-1823
Dennis J. Kinchen
Abstract Powertrain mounting systems design and development involves creating and optimizing a solution using specific mount rates and evaluation over multiple operating conditions. These mount rates become the recommended “nominal” rates in the specifications. The powertrain mounts typically contain natural materials. These properties have variation, resulting in a tolerance around the nominal specification and lead to differences in noise and vibration performance. A powertrain mounting system that is robust to this variation is desired. The design and development process requires evaluation of these mounts, within tolerance, to ensure that the noise and vibration performance is consistently met. During the hardware development of the powertrain mounting system, a library of mounts that include the range of production variation is studied. However, this is time consuming.
2017-06-05
Technical Paper
2017-01-1815
Pranab Saha, Satyajeet P. Deshpande
Abstract This paper discusses the importance of a dissipative sound package system in the automotive industry and how it works. Although this is not a new technique at this stage, it is still a challenge to meet the subsystem target levels that were originally developed for parts based on the barrier decoupler concept. This paper reviews the typical construction of a dissipative system and then emphasizes the importance of different layers of materials that are used in the construction, including what they can do and cannot do. The paper also discusses the importance of the proper manufacturing of a part.
2017-06-05
Technical Paper
2017-01-1818
Ramya Teja, T. R. Milind, Rodney C. Glover, Sunil Sonawane
Abstract Helical gears are commonly used instead of spur gears due to their potential higher load carrying capacity, efficiency and lower noise. Transmission Error (TE) is defined as deviation from perfect motion transfer by a gear pair. TE is dominant source of gear whine noise and hence gears pairs are generally analyzed and designed for low TE. In the process of designing helical gears for lower TE, the shuttling moment can become a significant excitation source. Shuttling moment is caused due to shifting of the centroid of tooth normal force back and forth across the lead. The amount of shuttling force or moment is produced by combination of design parameters, misalignment and manufacturing errors. Limited details are available on this excitation and its effect on overall noise radiated from gear box or transmission at its gear mesh frequency and harmonics.
2017-06-05
Technical Paper
2017-01-1839
Edward T. Lee
Abstract It is common for automotive manufacturers and off-highway machinery manufacturers to gain insight into the system’s structural dynamics by evaluating the system inertance functions near the mount locations. The acoustic response of the operator’s ears is a function of the vibro-acoustic characteristics of the system structural dynamics interacting with the cavity, with the actual load applied at the mount locations. The overall vibro-acoustic characteristics can be influenced by a change in local stiffness. To analyze the response of a system, it is necessary to go beyond analyzing its transfer functions. The actual load needs to be understood and applied to the transfer function set. Finite element (FE) based analysis provides a good foundation for deterministic solutions. However the finite element method decreases in accuracy as frequency increases.
2017-06-05
Journal Article
2017-01-1767
Zhenghong Shi, Teik Lim
Abstract Nonlinear interaction between time-varying hypoid gear mesh and bearing support is investigated in this study. Mesh parameters are time-varying due to complex tooth profile of hypoid gear. Bearing stiffness is formulated based on real geometry and instantaneous orbital position of rolling elements. Linear model is firstly analyzed to study the modal frequency and mode shape variations under different stiffness ratio between gear mesh and bearing support. Then, nonlinear analysis is conducted to compare the differences between linear and nonlinear dynamic response based on specific nonlinear conditions of geared rotor system. It is found that the coupling between hypoid gear mesh and bearing support can be either strong or weak depending on the ratio between mesh stiffness along line-of-action (LOA) and bearing stiffness in radial direction. Parametric studies indicate that dynamic mesh force is sensitive to bearing clearance for certain stiffness ratio.
2017-06-05
Journal Article
2017-01-1771
Mohamed El morsy, Gabriela Achtenova
Abstract Gear fault diagnosis is important in the vibration monitoring of any rotating machine. When a localized fault occurs in gears, the vibration signals always display non-stationary behavior. In early stage of gear failure, the gear mesh frequency (GMF) contains very little energy and is often overwhelmed by noise and higher-level macro-structural vibrations. An effective signal processing method would be necessary to remove such corrupting noise and interference. This paper presents the value of optimal wavelet function for early detection of faulty gear. The Envelope Detection (ED) and the Energy Operator are used for gear fault diagnosis as common techniques with and without the proposed optimal wavelet to verify the effectiveness of the optimal wavelet function. Kurtosis values are determined for the previous techniques as an indicator parameter for the ability of early gear fault detection. The comparative study is applied to real vibration signals.
2017-06-05
Technical Paper
2017-01-1760
Weimin Thor, J. Stuart Bolton
Abstract Due the increasing concern with the acoustic environment within automotive vehicles, there is an interest in measuring the acoustical properties of automotive door seals. These systems play an important role in blocking external noise sources, such as aerodynamic noise and tire noise, from entering the passenger compartment. Thus, it is important to be able to conveniently measure their acoustic performance. Previous methods of measuring the ability of seals to block sound required the use of either a reverberation chamber, or a wind tunnel with a special purpose chamber attached to it. That is, these methods required the use of large and expensive facilities. A simpler and more economical desktop procedure is thus needed to allow easy and fast acoustic measurement of automotive door seals.
2017-05-18
Journal Article
2017-01-9681
Mohamed El Morsy, Gabriela Achtenova
Abstract Bearing and gear condition monitoring are important to improve a mechanical system reliability and performance. In the early stage of bearing failures, the Bearing Characteristic Frequencies (BCFs) contain very little energy and are often overwhelmed by noise and higher-level macro-structural vibrations, an effective signal processing method would be necessary to eliminate such corrupting noise and interference. Referring to the non-stationary characteristics of roller bearing fault vibration signals, a roller bearing condition monitoring method based on Envelope Process to raw time-domain vibration signal and Autocorrelation enhancement to the residual signal is put forward in this paper. The concept of Envelope and Autocorrelation techniques and its implementation for defect identification are discussed. Also, distinction of bearing fault signal as cyclostationary from periodic signal for gear fault.
2017-03-28
Journal Article
2017-01-0131
Chiranth Srinivasan, Chonglin Zhang, Haiyang Gao, De Ming Wang, Jody Slike
Abstract In an automotive cooling circuit, the wax melting process determines the net and time history of the energy transfer between the engine and its environment. A numerical process that gives insight into the mixing process outside the wax chamber, the wax melting process inside the wax chamber, and the effect on the poppet valve displacement will be advantageous to both the engine and automotive system design. A fully three dimensional, transient, system level simulation of an inlet controlled thermostat inside an automotive cooling circuit is undertaken in this paper. A proprietary CFD algorithm, Simerics-Sys®/PumpLinx®, is used to solve this complex problem. A two-phase model is developed in PumpLinx® to simulate the wax melting process. The hysteresis effect of the wax melting process is also considered in the simulation.
Viewing 1 to 30 of 6730

Filter

Subtopics