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Viewing 241 to 270 of 6715
2015-09-01
Technical Paper
2015-01-1794
Yan Zhang, Macklini DallaNora, Hua Zhao
Controlled Auto Ignition (CAI), also known as Homogeneous Charge Compression Ignition (HCCI), is one of the most promising combustion technologies to reduce the fuel consumption and NOx emissions. In order to take advantage of the inherent ability to retain a large and varied amount of residual at part-load condition and its potential to achieve extreme engine downsizing of a poppet valve engine running in the 2-stroke cycle, a single cylinder 4-valves camless direct injection gasoline engine has been developed and employed to investigate the CAI combustion process in the 2-stroke cycle mode. The CAI combustion is initiated by trapped residual gases from the adjustable scavenging process enabled by the variable intake and exhaust valve timings. In addition, the boosted intake air is used to provide the in-cylinder air/fuel mixture for maximum combustion efficiency.
2015-09-01
Technical Paper
2015-01-1818
Kangwoo Seo, Hua Zhao
In order to investigate feasibility of DME (Di-methyl ether) assisted gasoline CAI (controlled-auto ignition) combustion, direct DME injection is employed to act as the ignition source to trigger the auto-ignition combustion of premixed gasoline/air mixture with high temperature exhaust gas. Intake re-breathing valve strategy is adopted to obtain internal exhaust recirculation (EGR) that regulates heat release rate and ignitability of the premixed gasoline and air mixture. The effects of intake re-breathing valve timing and 2nd DME injection timing of different split injection ratios were investigated and discussed in terms of combustion characteristics, emission and efficiencies. The analyses showed that re-breathing intake valve timing had a large effect on the operation range of CAI combustion due to EGR and intake temperature variation.
2015-09-01
Technical Paper
2015-01-1860
Xianyin Leng, Zhixia He, Yu Jin, Wenjun Zhong, Wuqiang Long
The intersecting hole nozzle, in which each orifice is formed by the converging of two or more child-holes, was proposed for the purpose of enhancing the internal turbulence in diesel nozzle, so as to promote the fuel atomization. In this paper, the internal flow characteristics of a cylindrical hole nozzle and two intersecting hole nozzles are studied by CFD simulation. The results show that, compared with conventional cylindrical hole nozzle, the internal flow of intersecting hole nozzles is characterized with slower rate of pressure decrease in the hole, none or very little cavitation, as well as about 20% to 30% higher discharge coefficients, especially under conditions of high injection pressure. Additionally, the setting of the blind hole as a disturbing domain in the intersecting hole nozzle results in more perturbation for internal flow, which will be beneficial for fuel atomization.
2015-09-01
Technical Paper
2015-01-1943
Yuichiro Miura, Shinya Sasaki, Tsuyoshi Kashio, Ayumi Takahashi
Investigation of both intake valve deposit (IVD) formation tendency and the effect of surrounding conditions (e.g. atmospheric temperature) on IVD formation was conducted using poly aromatics-rich gasoline in a port fuel injected (PFI) engine. The IVD mostly consisted of carbonaceous deposit and this was shown to be derived from the heavier poly aromatic fuel molecules and engine oil. Analysis also indicated that some metals in the deposit structure came from additives of lubricating oil and the wear and/or corrosion within the engine. In this engine test, there was a significant effect of room temperature where higher room temperatures correlated with higher levels of IVDs. These results illustrate the importance of the surrounding condition in order to understand the IVD issues, higher IVDs weights will result under hotter driving (e.g. in summer) condition.
2015-09-01
Technical Paper
2015-01-1987
Lei Shi, Hualei Li, Huiyan Zhang, Xiaojian Mao, Kangyao Deng, Bo Liu, Lin Hua
The concept of regulated two-stage turbocharging system is proposed to provide high boost pressure level over a wide range of engine speed by regulating the energy distribution of two turbochargers. However, the control strategy of turbine bypass valve becomes more complicated due to the frequently changing working of vehicle diesel engines. In this paper, a two-stage turbocharging system was matched for D6114 diesel engine to improve the low-speed torque. The effect of valve opening on the steady-state and transient performance was analyzed, and two different regulating laws were determined according to the different optimum aims. Then the transient response characteristics of two different regulating laws were studied and optimized at three speeds with the transient loading test. For steady-state performance, the output power and fuel efficiency were increased with the matched turbocharging system.
2015-09-01
Technical Paper
2015-01-1945
Alessandro Montanaro, Luigi Allocca
During an injection process, a fluid undergoes a sudden pressure drop across the nozzle. If the pressure downstream the injector is below the saturation value of the fluid, superheated conditions are reached and thermodynamic instabilities realized. In internal combustion engines, flashing conditions greatly influence atomization and vaporization processes of a fuel as well as the mixture formation and combustion. This paper reports imaging behavior of a fuel under both flash boiling and non-flash boiling conditions. A GDI injector, eight-hole, 15.0 cc/s @ 10 MPa static flow, injected a single-component fluid (iso-octane), generating the spray. Experiments were carried out in an optically-accessible constant-volume quiescent vessel by Mie-scattering technique. A C-Mos high-speed camera was used to acquire cycle-resolved images of the spray evolving in the chamber filled with N2 which pressure ranged between 0.05 and 0.3 MPa.
2015-09-01
Technical Paper
2015-01-2038
Yuichiro Kajiki, Hiroki Takata, Katsuhiro Ashihara, Akihiro Honda, Kazunari Takenaka, Hirofumi Michioka
Engine friction reduction is an effective means to improve fuel consumption. Fluid friction reduction of main bearing is examined for engine friction reduction in cold condition. As one of the examinations, it was focused on low temperature of lubricating oil in the early stage during engine cold start. In hydrodynamic lubrication, the oil film temperature is maintained by balance between heat generation and heat transfer. The heat generation is generated by shear of lubricating oil. The factors of the heat transfer, the following elements are considered as follows, A) The heat transfer to a crank shaft, B) The heat transfer to a bearing, C) The heat transfer by convection. If the heat generation is constant, oil film temperature is increased by reduction of heat transfer. It is considered that the reduction of oil leakage and reduction of the heat transfer by convection is equivalent.
2015-09-01
Technical Paper
2015-01-1906
Po-Wen Tu, Hongming Xu, Dhananjay Kumar Srivastava, Karl Dean, Daliang Jing, Li Cao, Adam Weall, Jens Krueger Venus
The large eddy simulation (LES) with Volume of Fluid (VOF) interface tracking method in Ansys-FLUENT has been used to study the effects of nozzle hole geometrical parameters on gasoline direct injection (GDI) fuel injectors, namely the effect of inner hole length/diameter (L/D) ratio and counter-bore diameters on near field spray characteristics. Using iso-octane as a model fuel at the fuel injection pressure of 200 bar, the results showed that the L/D ratio variation of the inner hole has a more significant influence on the spray characteristics than the counter-bore diameter variation. Reducing the L/D ratio effectively increases the mass flow rate, velocity, spray angle and reduces the droplet size and breakup length. The increased spray angle results in wall impingements inside the counter-bore cavity, particularly for L/D=1 which can potentially lead to increased deposit accumulation inside fuel injectors.
2015-09-01
Journal Article
2015-01-1837
Takayuki Fuyuto, Yoshiaki Hattori, Hayato Yamashita, Makoto Mashida
The backward flow of the hot burned gas surrounding a diesel flame was found to be one of the factors dominating the set-off length (also called the lift-off length), that is, the distance from a nozzle exit into which a diffusion flame cannot intrude. In the combustion chamber of an actual diesel engine, the entrainment of the surrounding gas into a spray jet from a multi-hole nozzle is restricted by the walls and adjacent spray jets, which induces the backward flow of the surrounding gas. A new momentum theory to calculate the backward flow velocity was established by extending Wakuri's momentum theory. Shadowgraph imaging in an optical engine successfully visualized the backward flow of the hot burned gas.
2015-09-01
Journal Article
2015-01-1850
Michele Battistoni, Claudio Poggiani, Sibendu Som
This paper reports investigations on diesel jet transients, accounting for internal nozzle flow and needle motion. The calculations are performed with Large Eddy Simulation (LES) turbulence model by coupling the internal and external multiphase flows simultaneously. Short and multiple injection strategies are commonly used in internal combustion engines. Their features are significantly different from those generally found in steady state conditions, which have been extensively studied in the past, however, these conditions are seldom reached in modern engines. Recent researches have shown that residual gas can be ingested in the injector sac after the end-of-injection (EOI) and undesired dribbles can be produced. Moreover, a new injection event behaves differently at the start-of-injection (SOI) depending on the sac initial condition, and the initial spray development can be affected for the first few tens of μs.
2015-06-15
Technical Paper
2015-01-2368
Babitha Kalla, Sanjeevgouda Patil, Mansinh Kumbhar
Abstract Idle NVH (Noise Vibration Harshness) is one of the major quality parameters that customer looks into while buying the vehicle. Idle shake is undesirable vibrations generated from Engine while it is in idling condition. These low frequency vibrations affects both driver and passenger comfort. Vibrations are perceived by customer through the interfaces such as the seats, floor, and steering wheel. The frequencies of vibration felt by customer ranges between 10-30 Hz and varies based on engine configurations. There are two factors that are critical to the vehicle idle NVH quality, 1. Engine excitation force and 2. Vehicle sensitivity to excitation forces (Transfer function). Even though the engine excitation forces are governed by cylinder combustion process inside the cylinder and engine mass, it is also largely affected by how well the engine and transmission are supported on vehicle through isolators.
2015-06-15
Technical Paper
2015-01-2190
Manchi Venkateswara Rao, S Nataraja Moorthy, Prasath Raghavendran
Abstract Mount development and optimization plays an important role in the NVH refinement of vehicle as they significantly influence overall driving experience. Dynamic stiffness is a key parameter that directly affects the mount performance. Conventional dynamic stiffness evaluation techniques are cumbersome and time consuming. The dynamic stiffness of mount depends on the magnitude of load, frequency of application and the working displacement. The above parameters would be far different in the test conditions under which the mounts are normally tested when compared to operating conditions. Hence there is need to find the dynamic stiffness of mounts in actual vehicle operating conditions. In this paper, the dynamic stiffness of elastomeric mounts is estimated by using a modified matrix inversion technique popularly termed as operational path analysis with exogenous inputs (OPAX).
2015-06-15
Technical Paper
2015-01-2212
A. Elsawaf, H. Metered, T. Vampola, Z. Sika
Abstract Active vibration control is the most effective method used for suppressing vibrations from external sources. This paper presents the particle swarm optimization (PSO) algorithm to search about the optimum feedback controller gains for the active mount suspension, for the first time, to reduce the vibrations level of a structural system. It consists of vibrating mass and flexible beam subjected to an external disturbance. A mathematical model and the equations of motion of the structure system with an active mount suspension are simulated using Matlab/Simulink software. The active controller was designed to control the first three modes of the structure. The proposed PSO algorithm aims to minimize the acceleration of the suspended mass as the objective function with constraint of the actuator force. Vibrations level is examined theoretically in order to assess the effectiveness of the proposed controller.
2015-06-15
Technical Paper
2015-01-2225
Peng Yu, Tong Zhang, Jing Li, Shiyang Chen, Rong Guo
Abstract Faced on transient vibration of EV, considering the characteristics of the electric drive system, active and passive integrated transient vibration control method of power train mounting system was proposed. Models of power train system and mounting system were established, modal characteristics were grasped by simulation and experiment. A feed-forward controller was constructed from the facet of active control, mounting system transient vibration and power train torsion vibration were reduced. Based on this, further optimization of mounting system was conducted from a passive control perspective. Results show that the active and passive integrated control method can effectively reduce the dynamic reaction force of mounting points, improve the vibration conditions of power train and vehicle body as well.
2015-06-15
Technical Paper
2015-01-2350
Jiantie Zhen, Scott Fredrickson
Abstract Off-highway machine mounting system isolation, especially the cab mounting system, significantly affects the operator comfort by providing damping to the harsh inputs and isolating the structure-borne energy from traveling into the cab. Mounting system isolation performance is decided not only by the isolation component, but also the mounting bracket structure, and should be treated as a system. This paper gives a review of how the mounting system isolates structural energy and the effect of the bracket structure stiffness to the mounting system isolation performance.
2015-06-15
Technical Paper
2015-01-2352
Chaitanya Krishna Balla, Sudhakara Naidu, Milind Narayan Ambardekar
Abstract Noise Vibration and Harshness (NVH) refinement is one of the important parameters in modern vehicle development. In city traffic conditions, idling is an engine operating condition where a driver focuses attention more to his/her vehicle. Tactile vibration & noise levels inside the cab play an important role in all vehicles, especially those powered by diesel engines where combustion pressures are higher. They lead to discomfort & fatigue of passengers of even a low cost vehicle. Now its idle NVH is influenced mainly by vibration-isolation provided by power-train (PT) mounting design, This paper describes steps taken to improve the idle vibrations at a driver seat of a small commercial vehicle (SCV) with a 2-cylinder diesel engine of 800 cc through redesign of PT-mounting along with fine tuning of idle speed of the engine. A resonance was avoided between the first firing order at idling and PT rigid-body mode in pitching.
2015-06-15
Technical Paper
2015-01-2139
E.J. Grift, E. Norde, E.T.A. Van der Weide, H.W.M. Hoeijmakers
Abstract In this study the characteristics of ice crystals on their trajectory in a single stage of a turbofan engine compressor are determined. The particle trajectories are calculated with a Lagrangian method employing a classical fourth-order Runge-Kutta time integration scheme. The air flow field is provided as input and is a steady flow field solution governed by the Euler equations. The single compressor stage is represented using a cascaded grid. The grid consists of three parts of which the first and the last part are stator parts and the centre part is a rotor. Each particle is modelled as a non-rotating rigid sphere. The remaining model does allow the exchange of heat and mass to and from the particle resulting in a mass, temperature and phase change of the particle. The phase change is based on a perfectly concentric ice core-water film model and it is assumed that the particle is at uniform temperature.
2015-06-15
Technical Paper
2015-01-2132
David L. Rigby, Joseph Veres, Colin Bidwell
Abstract Three-dimensional simulations of the Honeywell ALF502 low pressure compressor (sometimes called a booster) using the NASA Glenn code GlennHT have been carried out. A total of eight operating points were investigated. These operating points are at, or near, points where engine icing has been determined to be likely. The results of this study were used, in a companion paper, for further analysis such as predicting collection efficiency of ice particles and ice growth rates at various locations in the compressor. In an effort to minimize computational effort, inviscid solutions with slip walls are produced. A mixing plane boundary condition is used between each blade row, resulting in convergence to steady state within each blade row. Comparisons of the results are made to other simplified analysis. An additional modification to the simulation process is also presented.
2015-06-15
Technical Paper
2015-01-2181
Dong Guo, Yawen Wang, Teik Lim, Peng Yi
Abstract A combined lumped parameter, finite element (FE) and boundary element (BE) model is developed to predict the whine noise from rear axle. The hypoid geared rotor system, including the gear pair, shafts, bearings, engine and load, is represented by a lumped parameter model, in which the dynamic coupling between the engaging gear pair is represented by a gear mesh model condensed from the loaded tooth contact analysis results. The lumped parameter model gives the dynamic bearing forces, and the noise radiated by the gearbox housing vibration due to the dynamic bearing force excitations is calculated using a coupled FE-BE approach. Based on the predicted noise, a new procedure is proposed to tune basic rear axle design parameters for better sound quality purpose. To illustrate the salient features of the proposed method, the whine noise from an example rear axle is predicted and tuned.
2015-06-15
Technical Paper
2015-01-2136
Francisco José Redondo
A system has been designed for the A400M wherein engine air intake ice protection is provided by hot air bled from the engine cooled by air from inside the nacelle with a jet pump. Two variants of the system were developed. The first had an active temperature and pressure control downstream of the jet pump, and the second was without temperature control. Maximum temperature was a constraint for the design of the system since the engine air intake is manufactured in aluminum. In addition, several other constraints appeared during the detailed design of the system; the tight space allocation inside the nacelle limited the length of the jet pump, the low temperature provided by the engine bleed in flight idle limited the secondary flow used to cool the engine bleed, and the complex air distribution needed to supply air to the intake areas.
2015-06-15
Technical Paper
2015-01-2245
Mohammad Moetakef, Abdelkrim Zouani
Abstract A CAE method has been developed to address engine tonal noise and whine due to the excitation from a gerotor oil pump. The method involves a multidisciplinary approach including CFD, frequency-response structural analysis and acoustic analysis. The results from the application of the method applied to a couple of pumps with different designs are discussed. Engine tonal noise improvement through reduction in the excitation source from the pump and also stiffening the excitation path from the pump to the engine are studied. The effect of component modal alignment with oil pump orders is addressed as well.
2015-06-15
Journal Article
2015-01-2227
Scott Allen Noll, Benjamin Joodi, Jason Dreyer, Rajendra Singh
Abstract Elastomeric joints such as mounts and suspension bushings undergo broadband excitation and are often characterized through a cross-point dynamic stiffness measurement; yet, at frequencies above 100 Hz for many elastomeric components, the cross- and driving-point dynamic stiffness results significantly deviate. An illustrative example is developed where two different sized mounts, constructed of the same material and are shaped to achieve the same static stiffness behavior, exhibit drastically different dynamic behavior. Physical insight is provided through the development of a reduced order single-degree-of-freedom model where an internal resonance is explained. Next, a method to extract the parameters for the reduced order model from a detailed finite element bushing model is provided.
2015-06-15
Journal Article
2015-01-2333
Brandon Sobecki, Patricia Davies, J Stuart Bolton, Frank Eberhardt
Abstract Component sound quality is an important factor in the design of competitive diesel engines. One component noise that causes complaints is the gear rattle that originates in the front-of-engine gear train which drives the fuel pump and other accessories. The rattle is caused by repeated tooth impacts resulting from fluctuations in differential torsional acceleration of the driving gears. These impacts generate a broadband, impulsive noise that is often perceived as annoying. In most previous work, the overall sound quality of diesel engines has been considered without specifically focusing on predicting the perception of gear rattle. Gear rattle level has been quantified based on angular acceleration measurements, but those measurements can be difficult to perform. Here, the emphasis was on developing a metric based on subjective testing of the perception of gear rattle.
2015-06-15
Journal Article
2015-01-2182
Yawen Wang, Junyi Yang, Xuan Li, Guohua Sun, Teik Lim
Abstract Due to the design of lightweight, high speed driveline system, the coupled bending and torsional vibration and rotordynamics must be considered to predict vibratory responses more realistically. In the current analysis, a lumped parameter model of the propeller shaft is developed with Timoshenko beam elements, which includes the effect of rotary inertia and shear deformation. The propeller shaft model is then coupled with a hypoid gear pair representation using the component mode synthesis approach. In the proposed formulation, the gyroscopic effect of both the gear and propeller shaft is considered. The simulation results show that the interaction between gear gyroscopic effect and propeller shaft bending flexibility has considerable influence on the gear dynamic mesh responses around bending resonances, whereas the torsional modes still dominate in the overall frequency spectrum.
2015-06-15
Journal Article
2015-01-2178
Mohamed El Morsy, Gabriela Achtenova
Abstract When localized fault occurs in a bearing, the periodic impulsive feature of the vibration signal appears in time domain and the corresponding Bearing Characteristic Frequencies (BCFs) emerge in frequency domain. The common technique of Fast Fourier Transforms (FFT) and Envelope Detection (ED) are always used to identify faults occurring at the BCFs. In the early stage of bearing failures, the BCFs contain very little energy and are often overwhelmed by noise and higher-level macro-structural vibrations. In order to extract the weak fault information submerged in strong background noise of the gearbox vibration signal, an effective signal processing method would be necessary to remove such corrupting noise and interference. Optimal Morlet Wavelet Filter and Envelope Detection (ED) are applied in this paper.
2015-06-15
Journal Article
2015-01-2307
Neil Figurella, Rick Dehner, Ahmet Selamet, Keith Miazgowicz, Ahsanul Karim, Ray Host
Abstract The effect of aerodynamically induced pre-swirl on the acoustic and performance characteristics of an automotive centrifugal compressor is studied experimentally on a steady-flow turbocharger facility. Accompanying flow separation, broadband noise is generated as the flow rate of the compressor is reduced and the incidence angle of the flow relative to the leading edge of the inducer blades increases. By incorporating an air jet upstream of the inducer, a tangential (swirl) component of velocity is added to the incoming flow, which improves the incidence angle particularly at low to mid-flow rates. Experimental data for a configuration with a swirl jet is then compared to a baseline with no swirl. The induced jet is shown to improve the surge line over the baseline configuration at all rotational speeds examined, while restricting the maximum flow rate. At high flow rates, the swirl jet increases the compressor inlet noise levels over a wide frequency range.
2015-06-15
Journal Article
2015-01-2364
Xianpai Zeng, Jared Liette, Scott Noll, Rajendra Singh
Abstract The vibration isolation effectiveness of powertrain mount configurations is examined for electric vehicle application by considering the effect introduced by internal mount resonances. Unlike internal combustion engines where mounts are typically designed only for static support and low frequency dynamics, electric motors have higher excitation frequencies in a range where mount resonances often occur. The problem is first analytically formulated by considering a simple 3-dimensional powertrain system, and the vibration isolation effectiveness significantly deteriorates at the mount resonance(s). It is shown that by modifying the mount shape, the mount resonance(s) can be shifted while maintaining the same static rate, tuning the frequency away from any engine excitation or natural frequencies. Further, internal mount resonances are utilized to improve vibration isolation over a narrow frequency range, using non-identical mounts to split mount resonance peaks.
2015-06-15
Journal Article
2015-01-2229
Benjamin Joodi, Scott Allen Noll, Jason Dreyer, Rajendra Singh
Abstract Elastomeric joints are utilized in many automotive applications, and exhibit frequency and excitation amplitude dependent properties. Current methods commonly identify only the cross-point joint property using displacement excitation at stepped single frequencies. This process is often time consuming and is limited to measuring a single dynamic stiffness term of the joint stiffness matrix. This study focuses on developing tractable laboratory inverse experiments to identify frequency dependent stiffness matrices up to 1000 Hz. Direct measurements are performed on a commercial elastomer test system and an inverse experiment consisting of an elastic beam (with a square cross section) attached to a cylindrical elastomeric joint. Sources of error in the inverse methodology are thoroughly examined and explained through simulation which include ill-conditioning of matrices and the sensitivity to modeling error.
2015-04-14
Technical Paper
2015-01-0431
KI Woo Sung, Jong Gurl Kim, Dae-Un Sung, Hye Mi Kim
Abstract This study examined various warranty data analysis methods to identify and study the one most suitable for Hyundai Motor warranty data. The drawbacks of the conventional life table method were overcome to develop an analysis method optimized for vehicle characteristics. The proposed method was examined for its suitability to various applications, such as providing the information necessary for determining the service life of parts, verifying the effects of design changes, and designing warranty and maintenance policies. The analysis data used in this study were derived from the 10-year powertrain parts warranty data of vehicles sold in the USA, South Korea, and China.
2015-04-14
Technical Paper
2015-01-0600
Marc Rosenbaum
Abstract A new generation of 3D inspection machines is now available to verify in line 3D dimensional conformity of complex parts - especially Powertrain ones - with accuracy down to 0.1 μm within manufacturing cycle time of large series. Inspecting in line 100% of production with an accuracy and at speed compatible with the most demanding part accuracy and fastest cycle time is presently already a reality for some large tier1 suppliers in Europe. Purpose of this paper is to introduce this breakthrough technology using state of the art non-contact sensing technology allied with innovative mechanics and the latest developments in 3D metrology software
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