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Viewing 1 to 30 of 5047
Technical Paper
2014-11-11
Alessandro Franceschini, Emanuele Pellegrini, Raffaele Squarcini
Nowadays the challenge in design auxiliary device for automotive small engine is focused on the packaging reduction and on the increase of the performances. This requirements are in contrast to each other and in order to fulfil the project specifications, new and more refined design tools and procedures need to be developed. This paper presents a calculation loop developed by Pierburg Pump Technology Italy S.p.a. (PPT). It supports the design of a variable displacement oil pump component for engine applications. The work is focused on the fatigue life evaluation of a joint, which transmits the drive torque from the engine to the oil pump. The aim of the procedure is to calculate the onset of the surface fatigue phenomenon in the hexagonal joint which drives the oil pump, taking into account the axes misalignment and the flat to flat clearance. The study has involved several matters, experimental measures, CFD, MBA and FEM analyses. A calculation procedure has been set up in order to consider all the necessary loads applied on the joint.
Technical Paper
2014-11-11
T Manikandan, S Sarmadh Ameer, A Sivakumar, Samaraj Dhinagar
The proposed paper is on electrical energy conservation in a two wheeler. Electrical energy generation adds a maximum of 10% excess load torque on an engine and hence saving electrical energy would ultimately reduce the consumption of fuel. Load Control Module is a single intelligent device which is placed in between electrical energy generation and consumption. The Module controls and distributes energy to the corresponding loads depending on parameters like battery voltage, engine RPM, overhead light illumination levels and load usage time. The Module prioritizes battery charging for maintaining the life of the battery. The Module has a microcontroller and it is programmed with algorithm for prioritization and energy distribution with respect to input conditions. A vehicle fitted with the Load Control Module was tested in city driving cycle (CDC) condition as per ARAI (Automotive Research Association of India) standard and it was found that the electrical loading decreased to about 30% when compared to vehicle with uncontrolled loading.
Technical Paper
2014-11-11
T Manikandan, S Sarmadh Ameer, A Sivakumar, Davinder Kumar, R Venkatesan, VenkataKalyana Kumar
The proposed paper is on advanced vehicle information panel which shall display instant mileage zone in which the user is operating with inputs from engine crank sensor and vehicle speed sensor alone. And moreover, gear assistance and throttle assistance through visuals is provided. Mileage data for different engine loading at different Speeds is pre-calculated at standard conditions and fed into a micro-controller. In real time, the engine loading, by means of intelligent software, is sensed by engine crank sensor and based on the pre-fed value, the mileage zone of the vehicle at that particular instant is to be displayed using an information panel. Based on the relation between speed sensor and engine crank sensor when the vehicle is running, the gear in which the vehicle is running is to be calculated. For a vehicle running in a certain gear and in certain speed, the ideal engine loading and mileage zone is predefined. So when the user is riding in a certain gear with certain engine load, the micro controller compares that with the programmed data which is the ideal condition data, and assists the user, in case the rider is not riding the vehicle as per the ideal data, by gear up/down prompt or throttle up/down prompt by means of the said information panel.
Technical Paper
2014-09-30
Matt Zwick
Abstract The base design of commercial vehicle wheel end systems has changed very little over the past 50 years. Current bearings for R-drive and trailer wheel end systems were designed between the 1920's and the 1960's and designs have essentially remained the same. Over the same period of time, considerable gains have been made in bearing design, manufacturing capabilities and materials science. These gains allow for the opportunity to significantly increase bearing load capacity and improve efficiency. Government emissions regulations and the need for fuel efficiency improvements in truck fleets are driving the opportunity for redesigned wheel end systems. The EPA and NHTSA standard requires up to 23% reduction in emissions and fuel consumption by 2017 relative to the 2010 baseline for heavy-duty tractor combinations. This paper summarizes the history of current wheel end bearing designs and the opportunity for change to lighter-weight, cooler-running and more fuel-efficient wheel bearing designs to help meet the new industry standards.
Technical Paper
2014-09-30
Meng-Huang Lu, Figen Lacin, Daniel McAninch, Frank Yang
Abstract Diesel exhaust aftertreatment solutions using injection, such as urea-based SCR and lean NOx trap systems, effectively reduce the emission NOx level in various light vehicles, commercial vehicles, and industrial applications. The performance of the injector plays an important role in successfully utilizing this type of technology, and the CFD tool provides not only a time and cost-saving, but also a reliable solution for extensively design iterations for optimizing the injector internal nozzle flow design. Inspired by this fact, a virtual test methodology on injector dosing rate utilizing CFD was proposed for the design process of injector internal nozzle flows. For a low-pressure (less than 6 bar) injector application, the characteristic Reynolds number based on the diameter and mass flow rate of the inlet, return flow outlet, and nozzle exit of the injector might range from 2000 to 20000, therefore, employing a flow-physics based viscous model for building up a virtual test methodology is critical to properly capture the fluid dynamics of injector internal nozzle flow.
Technical Paper
2014-09-28
Sukumar T, Murugan Subramanian
Abstract This paper presents a systematic procedure for design and evaluation of snap fit for Quadruple System Protection Valve (QSPV) piston assembly. The QSPV piston is assembled with housing by means of snap joint. Snap joints are a very simple, economical and rapid way of joining two different components. All types of snap joints have in common the principle that a protruding part of one component, e.g., a hook, stud or bead is deflected briefly during the joining operation and catches in a depression (undercut) in the mating component. After the joining operation, the snap-fit features should return to a stress-free condition. The joint may be separable or inseparable depending on the shape of the undercut; the force required to separate the components varies greatly according to the design. It is particularly important to bear the following factors in mind when designing snap joints: Mechanical load during the assembly operation and force required for assembly.
Technical Paper
2014-09-16
Marco Amrhein, Jason Wells, Eric Walters, Seana McNeal, Brett Jordan, Peter Lamm
Abstract Transient operating conditions in electrical systems not only have significant impact on the operating behavior of individual components but indirectly affect system and component reliability and life. Specifically, transient loads can cause additional loss in the electrical conduction path consisting of windings, power electronic devices, distribution wires, etc., particularly when loads introduce high peak vs. average power ratios. The additional loss increases the operating temperatures and thermal cycling in the components, which is known to reduce their life and reliability. Further, mechanical stress caused by dynamic loading, which includes load torque cycling and high peak torque loading, increases material fatigue and thus reduces expected service life, particularly on rotating components (shaft, bearings). This article investigates the aforementioned stress mechanisms and provides analysis techniques and metrics to quantify the impact of transient operating conditions onto system and component reliability and life.
Technical Paper
2014-09-16
Jamie Skovron, Laine Mears, Durul Ulutan, Duane Detwiler, Daniel Paolini, Boris Baeumler, Laurence Claus
Abstract A state of the art proprietary method for aluminum-to-aluminum joining in the automotive industry is Resistance Spot Welding. However, with spot welding (1) structural performance of the joint may be degraded through heat-affected zones created by the high temperature thermal joining process, (2) achieving the double-sided access necessary for the spot welding electrodes may limit design flexibility, and (3) variability with welds leads to production inconsistencies. Self-piercing rivets have been used before; however they require different rivet/die combinations depending on the material being joined, which adds to process complexity. In recent years the introductions of screw products that combine the technologies of friction drilling and thread forming have entered the market. These types of screw products do not have these access limitations as through-part connections are formed by one-sided access using a thermo-mechanical flow screwdriving process with minimal heat. The friction drilling, thread forming process, hereto referred to as “FDS” is an automated continuous process that allows multi-material joining by utilizing a screw as both the tool and the fastener.
Technical Paper
2014-09-16
Samuel Baha II
Hybrid (bolted/bonded) joining is becoming one of the innovative joining processes for light weight structures in the transport industry, especially in the aerospace industry where weight reduction and high joining requirements are permanent challenges. Combining the adhesive bonding with the mechanical joining -riveting for instance- can lead to an enhancement of the properties of the joint compared to the wide established riveting, as a result of a synergistic load bearing interaction between the fastener and the adhesive bondline. The influence of the rivet installation process on a hybrid joint regarding the joint stress state, the change of the bondline thickness as well as its effects on the joint performance and load transfer are some of the factors that drive the users to a better understanding of the hybrid joining process. This paper deals therefore on one hand with the numerical simulation of the rivet installation process in an adhesively bonded joint to understand the phenomena occurring during the installation process and on the other hand with the investigation of the load transfer depending on the joint parameters.
Technical Paper
2014-09-16
Pietro Ladisa, Gabriele Santonico
Abstract The marman interface is widely used in space applications to fit the spacecrafts to the launch vehicle and it is the same interface that allows the integration, test and transport of the satellites (AIT). It is usually designed for launch loads with related flight design safety factors and margins, but this is not always compatible with the handling and transport environment. In particular some criticalities are evidenced during the transport of satellites, where they are mounted in the container in horizontal position therefore subjected to bending loads due to gravity and transport dynamic loads. The study deals with a finite element analysis approach in the calculation and verification of marman clamp bands used for spacecraft AIT operations. The paper describes the details of modeling of the clamp band parts, the involved spacecraft launch vehicle interface ring and the MGSE interface. All these parts are in contact and this configuration has been modeled adopting the most recent non linear contact analysis techniques.
Technical Paper
2014-06-30
Farokh Kavarana, Kin Yu, Tyler Robbins, John DeYoung
Abstract The advantages of hydraulic mounts over conventional elastomeric mounts for NVH refinement are well known, particularly in the area of engine and suspension mounts. Recently, hydraulic mounts have been successfully employed as body mounts between the frame and cab, principally to control freeway hop in pickup trucks. Due to their ability to provide increased damping at small displacements, hydraulic body mounts also have good potential to reduce smooth road shake. This paper documents the reduction in smooth road shake performance of a full size pickup truck. Hydraulic body mounts tuned to the frequency of the smooth road shake sensitivity area were added to the rearmost cab mount location. Both tire-wheel balance and uniformity were set to the highest production level specification allowed and the effect of hydraulic cab mount was measured experimentally during smooth road driving at medium to high speeds. Hydraulic body mounts were found to be successful in reducing smooth road floor shake by up to 6 dB, thereby considerably refining the vehicle vibration due to first order tire-wheel input forces.
Technical Paper
2014-05-07
Marcos dos Santos, Ricardo Guedes Manini, Jayme B. Curi, Cleber Chiqueti
Abstract ”U” bolts are fixing elements and they are used to clamp an elastic joint. From the past, they still looking as an old design and unfortunately, suspension engineers are not specialists in fasteners and elastic joints. That is why we will show important assumptions and concepts to design and specifications this clamp element “U” bolt and its influence over leaf-springs. Currently, “U” bolt is used to clamp an elastic or elastic-plastic joint of heavy duty suspension, formed by leaf-spring, axle, spring pad, “U” bolt plate. This kind of suspension is typically used to trucks, buses and trailers. We are wondering, which one important assumption that an engineer must be careful when designs a new suspension changing from old designs to an updated technology. We provide a theoretical analysis and a FEA analysis to compare torque efficacy x leaf-spring reactions and what are effects this relationship can cause in a suspension. To have a shortest development time and provide back an expected result from the suspension system, engineers should to consider more and new assumptions, evaluate virtual and practical performance of leaf-springs with “U” bolt designed to clamp all elastic joint and even the correct torque specification to the “U” bolt.
Technical Paper
2014-04-28
Ingrid Rasquinha, Reji Koshy Daniel
Abstract Environment, energy and safety concerns for vehicles have made improving strength-to-weight ratio of vehicles an imperative issue for the automobile industry. Tube hydroforming (THF) is an innovative forming technology, which can efficiently reduce the weight of a component or assembly, and at the same time, increase the part strength. THF produces parts with a high degree of part complexity (various cross-sections in a single piece) and dimensional stability. Tube hydroforming involves the expansion and sizing of tubes in a closed die under dynamic action of pressurized fluid, with simultaneous axial or radial compression. Best forming results can be achieved by the optimized combination of process parameters (internal pressure, feed, friction, load, blank thickness) and material properties (yield strength, tensile strength, n-value, r-value, elongation).With the help of case studies, this thesis presents how tube hydroforming has been used to shave mass off some conventionally produced auto components like chassis cross-members, trailing arms, crash members and exhaust housings.
Technical Paper
2014-04-28
Saral Bhanshali
Abstract This breakthrough development involves material conversion from aluminum die cast to polypropylene long fiber thermoplastic (40% long glass filled) for a two wheeler bracket of a leading automotive OEM. The plastic bracket was developed working in collaboration with the molder, glass supplier, technology collaborator and the OEM. The new part needed to be designed lighter in weight, easier to process and suitable for painting, outdoor exposure and stringent dynamic conditions. The scope of this study includes the evaluation of the new material from different viewpoints and comparison of the same with the existing material. The submission will go through the intricate analyses carried out in the development process and highlight the key advantages over aluminum. Studies will include static and dynamic analysis, fiber orientation studies, gate location studies, etc.
Technical Paper
2014-04-28
Ashok KK, Bade Simhachalam, Dhanooj Balakrishnan, Krishna Srinivas
Abstract In this paper, the application of tube Extrusion for the development of stepped tubular components is discussed. Thickness increase with respect to cold reduction of diameter is predicted with reasonable accuracy. Thickness increase, length increase and strain hardening coefficient for a given cold reduction of diameter of tube are obtained using LS-DYNA Software. True stress-plastic strain curves from the tensile test are used in the forming simulation using LS-DYNA. A special purpose machine is developed for the production of steering shaft components. Considerable reduction in weight is achieved by using stepped tubular components.
Technical Paper
2014-04-28
M. J. Rathod, H. A. Deore
Abstract Desired mechanical properties including wear resistance at affordable price are the key parameters for which ductile cast irons are widely selected. Particularly, in many automobile applications like brake cylinders, camshafts, connecting rods, gears, pistons and yokes ductile iron is used. Traditionally surface heat treatments like induction hardening and in recent times electron beam and laser hardening are used to improve wear and fatigue resistance of ductile irons. However, the laser surface hardening has a lot of advantages over others such as low distortion due to high power density, flexibility, accuracy, lack of quenching medium and limited grain growth. In this work, laser surface hardening of Ferrito pearlitic ductile iron grade has been carried out. Hardening was performed with a 400W continuous wave fiber laser with the objective to investigate the effect of local tempering in continuous laser multi-pass laser surface hardening on hardness profile of the specimen.
Technical Paper
2014-04-28
Shiva Kumar Manoharan, Christoph Friedrich
Abstract Self-loosening of bolted connections is a crucial failure mode for joints under transverse dynamic load. For some years, three dimensional finite element analysis has been enabled for avoiding experimental investigations of self-loosening. The aim of this paper is to emphasize the effect of joint design on the self-loosening of bolted connections, which is important for product development in early design stage. Joints consisting of internally threaded nut components are often heavier and stiffer as compared with light weight designs consisting of a separate nut. The difference of self-loosening is significant between arrangements with nut thread component and separate nut, although the design versions only contain slight modifications. Hence it is necessary to evaluate the effect of light weight design on self-loosening.
Technical Paper
2014-04-28
Shreyas Shingavi, Pankaj Bhirud, M. Nagi Reddy, Darshan Mishal
Abstract In Automotive world, different types of shield are used to safe guard the assembly from dirt and dust. These can deteriorate the performance and functioning of systems. Typically the dirt shields are not load carrying members, so preferred to have low gauges and low weight. Dirt shield has to cover many subassemblies, so it has intricate shape as well. Due to low gauge and complicated shape, the manufacturing of these shields becomes challenging in terms of maintaining assembly tolerances. In order to overcome these concerns, concurrent design approach is used. Using this approach manufacturing process of the parts is virtually simulated and residual stresses, strains, permanent set, spring back effect are evaluated. These results are cascaded to assembly load analysis, and results are monitored for deflections. Based on these results various interferences during actual assemblies or failure during assemblies like flushness can be predicted well in advance and design correction can be carried out at very early stage, resulting lower product development cost and time.
Technical Paper
2014-04-28
A. R. Kumbhar, S. A. Kulkarni, J. M. Paranjpe, N. V. Karanth
Abstract New process development of forging component require lot of process knowledge and experience. Even lots of trial-and-error methods need to be used to arrive at optimum process and initial billet dimensions. But with help of reliable computer simulation tools, now it is possible to optimize the complete process and billet dimensions without a single forging trial. This saves lot of time, energy and money. Additionally, simulation gives much more insight about the process and possible forging defects. In this paper, a complete forging process was needed to be designed for a complex component. With the help of computer simulation, the complete conventional forging process and modified forging process were simulated and optimized. Forging defects were removed during optimization of the process. Also billet weight optimization was carried out. Deciding the pre-forming shape of the billet was the main challenge. With use of computer simulation, an innovative pre-forming shape was arrived resulting in reducing billet input weight.
Technical Paper
2014-04-20
Ala Qattawi, Mahmoud Abdelhamid, Ahmad Mayyas, Mohammed Omar
1 The manufacturing of Origami based sheet metal products is a promising technology, mostly in terms of reducing the tooling and process complexity. This procedure can also be called fold forming, as it depends on exclusively shaping the required geometry via sequence of bends. However, the design analysis and modeling of folded sheet metal products are not fully mature, especially in terms of determining the best approach for transferring the analysis from a three-dimensional (3D) to a two-dimensional (2D) context. This manuscript discusses the extension of the Origami technique to the fold forming of sheet metal products represented in modeling approach and design considerations for the topological variations, the geometrical validity, and the variance of stress-based performance. This paper also details the optimization metrics that were developed to reflect the design and manufacturing differences among the possible topological and geometrical options for a single part design. These metrics target five different optimization objectives: material utilization, cost, ease of manufacturability, ease of handling, and mechanical behavior estimation.
Technical Paper
2014-04-01
Yinhong Liu, Dazhong Lao, Yixiong Liu, Ce Yang, Mingxu Qi
Abstract Variable nozzle turbine (VNT) adjusts the openings of its nozzles to insure the required flow at throat area, which broadens the operating range of the turbine, and improves the matching relationship between the turbocharger and the engine. But the changes of nozzle openings have significant influence on the flow field structure of downstream radial turbine. To evaluate this effect, the leakage flow through nozzle clearance in various nozzle openings were simulated by unsteady computational fluid dynamic (CFD). Meanwhile, the interaction between nozzle clearance leakage flow and nozzle wake were investigated to reveal its effects on aerodynamic losses and forced responses for downstream rotor. The results showed that the changes of nozzle openings not only affect the interaction between nozzle leakage flows and wake significantly, but also affect aerodynamic performance of the rotor and the blade forced response. With the decreases of nozzle openings, the nozzle leakage flow increases and the interaction between nozzle leakage flow and wake enhances.
Technical Paper
2014-04-01
Shigenori Ichinose, Kiyoshi Iwade, Yoshiharu Hata
Abstract The oil flow in the oil ring groove was observed in order to improve the oil ejection efficiency in the oil ring groove. The oil flow was visualized with a clear head piston using fluorescing agent and particles under motoring condition. The influences of oil ring specification on the direction and the velocity of the oil flow were evaluated. The velocity of the oil ring with oil vent holes was faster than that of the oil ring without oil vent holes. In the case of the oil ring with vent holes, the reverse flow of the oil toward the front side was observed in the back clearance. Therefore, oil vent holes can change the oil flow and improve the oil ejection efficiency in the oil ring groove.
Technical Paper
2014-04-01
Sandeep Kognole
Abstract Geometric Parameters of Gears are mainly driven by two parameters, 1) tooth bending strength & 2) surface durability (pitting). Gear design software (KISSSOFT / ROMAX) propose options on gear parameters for gear pair with result of tooth bending strength & surface durability. This paper does not describe the Gear design software application for optimization of geometric parameters of the gear tooth. It explains the engineering method for Gears parameter optimization. Without using gear design software, optimization of gear geometric parameters is possible by using the gear parameters of existing gear pair. Geometric parameters of existing gear are derived by span measurement method. The geometric parameters such as, Module, Helix angle, Tip/Root diameter, Face width & Tooth modification are optimized by using below parameters derived from existing gear pair Contact Ratio Tooth thickness ratio on working PCD for Pinion & Gear (Working PCD-Root Diameter) per module factor for Pinion & Gear Tip Clearance coefficient for Gear & Pinion The paper also describes a standard procedure to arrive at the optimized geometric parameters for the gear pair.
Technical Paper
2014-04-01
Mehdi Safaei, Shahram Azadi, Arash Keshavarz, Meghdad Zahedi
Abstract The main end of this research is the optimization of engine sub-frame parameters in a passenger car to reduce the transmitted vibration to vehicle cabin through DOE method. First, the full vehicle model of passenger car including all its sub-systems such as engine, suspension and steering system is modeled in ADAMS/CAR and its accuracy is validated by exerting swept sine and step input. After that, the schematic geometry of sub-frame is modeled in CAD software and transferred to ADAMS/CAR. Hence, the efficiency of the sub-frame in terms of reducing the induced vibration to vehicle cabin is examined through the various road inputs e.g. swept sine, step and random road input type (B). The results will illustrate that the sub-frame has significant effect in reduction of transmitted vibration to occupants. In order to optimize the sub-frame parameters, the sensitivity analysis is performed to derive effective parameters of sub-frame using DOE method. In this regard, the parameters which have dominant effect on transmitted vibration (the stiffness of sub-frame bushing in vertical direction) are optimized via RSM (Response Surface Method) method.
Technical Paper
2014-04-01
Sameer U. Kolte, David Neihguk, Abhinav Prasad, Samir Rawte, Aditya Gondhalekar
Abstract A typical powertrain mount design process starts with performing the system calculations to determine optimum mount parameters, viz. position, orientation and stiffness values to meet the desired NVH targets. Therefore, a 6 degrees of freedom lumped parameter system of powertrain and mounts is modelled in Matlab®. The approach is to decouple the torque roll axis mode from the remaining five rigid body modes so that the response to the torque pulses is predominantly ‘oscillations about Torque Roll Axis’. This is achieved by optimizing the above mount parameters within specified constraints so that ‘Rotation about the torque roll axis’ is one of the natural modes of vibration. The tool developed here uses ‘Particle Swarm Optimization(PSO) algorithm’ because of its ease of implementation and better convergence to the solution. The algorithm is programmed in TK solver®. Further, for the given torque input, the harmonic response of the powertrain mounted on optimized mounts, is evaluated for comparison with NVH targets.
Technical Paper
2014-04-01
Zamir Zulkefli, Maurice Adams
Abstract Gears are used in numerous applications where mechanical power needs to be transmitted as in the powertrain of cars, buses and other vehicles. These gears can potentially be a significant source of high-frequency vibration and radiated noise in a vehicle, which can be both harmful and objectionable to any listeners in the vicinity. A proposed approach to addressing the gear mesh-frequency vibrations is to utilize the low pass filtering effect of a hydrostatic bearing in a gear mesh-frequency noise mitigation system. This paper describes an experimental investigation of the low pass filtering effect of a hydrostatic bearing using an experimental setup involving a widely available materials testing machine. By using the materials testing machine, appropriately sized hydrostatic bearing and externally pressurized fluid supply system, empirical data was collected that allowed the frequency response of the hydrostatic bearing to be determined. The frequency response of the hydrostatic bearing clearly shows a low pass filtering effect on the applied dynamic loads.
Technical Paper
2014-04-01
Ralph S. Shoberg, Jeff Drumheller
Abstract Reliable wheel attachment must start with proper tightening of the lug nuts in order to achieve the clamping force necessary to hold the vehicle's wheels securely for all operating conditions. It is the purpose of this paper to provide a complete overview of the theory and practice of using torque-angle signature analysis methods to examine the installation and audits of wheel lug nuts. An accurate estimate of clamp load can be determined without actually measuring the clamp load. The torque-angle signature analysis, known as “M-Alpha”, performed on tightening and loosening curves provides a powerful tool to understand the integrity of a bolted joint when clamp load data is not available. This analysis technique gives insight into the frictional effects, material properties, and geometric factors that can affect the clamp load attained during the installation process.
Technical Paper
2014-04-01
John Morello
Abstract As automotive and commercial vehicle OEM's continue their quest to reduce cost, product selection, quality, and reliability must be maintained. On-engine and wheel located connection systems create the greatest challenges due to the extreme levels of vibration. In the past, devices were fewer, and there where less direct connects in high vibration locations (Engine/ wheel sensors, electronic controllers, fuel injectors). Instead, small wire harnesses (“pigtails”) were commonly used. These pigtails can dampen the effect of the environment which includes mild to severe vibration by keeping the environmental effect away from the electrical connection contact point. Electrically connecting directly to the device creates new challenges in the connection system with the increased threat of fretting corrosion. Suppliers supporting OEM's are attempting to meet these direct connect requirements with lubrication, precious metal plating, and high contact force contacts. Some are more effective than others, and all have their drawbacks.
Technical Paper
2014-04-01
Mark A. Shost, Ming-Chia Lai, Bizhan Befrui, Peter Spiekermann, Daniel L. Varble
Abstract Development of in-cylinder spray targeting, plume penetration and atomization of the gasoline direct-injection (GDi) multi-hole injector is a critical component of combustion developments, especially in the context of the engine downsizing and turbo-charging trend that has been adopted in order to achieve the European target CO2, US CAFE, and concomitant stringent emissions standards. Significant R&D efforts are directed towards the optimization of injector nozzle designs in order to improve spray characteristics. Development of accurate predictive models is desired to understand the impact of nozzle design parameters as well as the underlying physical fluid dynamic mechanisms resulting in the injector spray characteristics. This publication reports Large Eddy Simulation (LES) analyses of GDi single-hole skew-angled nozzles, with β=30° skew (bend) angle and different nozzle geometries. The objective is to extend previous works to include the effect of nozzle-hole length over diameter ratio (l/d) and fuel injection pressure on spray skew angle, spray plume cone angle and primary breakup length.
Technical Paper
2014-04-01
David Greif, Wilfried Edelbauer, Jure Strucl
Abstract The paper addresses aspects of modeling cavitating flows within high pressure injection equipment while considering the effects of liquid compressibility. The presented numerical study, performed using the commercial CFD code AVL FIRE®, mimics common rail conditions, where the variation in liquid density as a function of pressure may be relevant owing to very high pressure injection scenarios. The flow through the injector has been calculated and the conditions at the outlet of the nozzle orifice have been applied as inlet condition for subsequent Euler-Lagrangian spray calculations to investigate the effects of liquid compressibility treatment on spray propagation. Flows of such nature are of interest within automotive and other internal combustion (IC) related industries to obtain good spray and emissions characteristics. In the development process of the injection equipment, predictive methods using Computational Fluid Dynamics (CFD) contribute to lower development costs, improved engine efficiency, decreased emissions and nevertheless shorter development cycles.
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