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Viewing 31 to 60 of 58638
2011-05-17
Journal Article
2011-01-1550
Wei Sun, Yinong Li, Jingying Huang
Dual Mass Flywheel (DMF) has better damping capacity than the conventional Clutch Torsional Damper (CTD), and is more suitable for diesel engine, Dual Clutch Transmission (DCT) and hybrid vehicles. Dual Mass Flywheel-Radial Spring (DMF-RS) is a DMF that has a specific structure. In the light of working principal and static analysis, the hard nonlinear torsional stiffness of DMF-RS is derived in this paper, which is very important to a driveline damper. On this basis, a simulation model is developed to analyze the dynamic response of DMF and CTD excited by idle engine; the comparison of the two dampers reveals that the DMF has better damping capacity, high-frequency filter ability and can reduce crankshaft load.
2011-05-17
Technical Paper
2011-01-1551
Xia Hua, Teik Lim, Tao Peng
Spiral bevel gear dynamics are significantly affected by the flexibilities of shafts and bearings. In this study, a new shaft-bearing model has been proposed for computing the effective support stiffness. The results are applied to the lumped parameter dynamic model of spiral bevel geared rotor system with 3-bearing straddle-mounted pinion configuration. Also, using the multi-degree of freedom lumped parameter dynamic model and quasi-static three-dimensional finite element tooth contact analysis program, the responses of two typical shaft-bearing configurations used in automotive applications, that are the 3-bearing straddle mounted pinion configuration and the 2-bearing overhung mounted pinion configuration, are compared. The comparative analysis along with a set of parametric studies highlights their different contributions to the spiral bevel gear mesh characteristics and dynamic response.
2011-05-17
Technical Paper
2011-01-1553
Won Shin, Ashish Kanase, Sungwook Hwang, Sangbum Baek, Hyutae Shim, Seiwoong Oh
Abstract As automotive technology has been developed, gear whine has become a prominent contributor for cabin noise as the masking has been decreased. Whine is not the loudest source, but it is of high tonal noise which is often highly unpleasant. The gear noise originates at gear mesh. Transmission Error acts as an excitation source and these vibrations pass through gears, shafts and bearings to the housing which vibrates to produce noise on surrounding air. As microgeometry optimization target to reduce the fundamental excitation source of the noise, it has been favored method to tackle gear whine noise, especially for manual transmission. However, practicality of microgeometry optimization for the planetary gear system has been still in question, because of complex system structure and interaction among multi mesh gear sets make it hard to predict and even harder to improve. In this paper, successful case of whine noise improvement by microgeometry is presented.
2011-05-17
Technical Paper
2011-01-1554
Michael Swank, Patrick Lindemann
This paper describes the use of dynamic vibration absorbers in torque converters to reduce the torsional vibration levels of the vehicle drivetrain. The use of both tuned mass absorbers and centrifugal pendulum absorbers (CPA) are discussed. In the case of the tuned mass absorber, the absorber is tuned near the lugging limit of the torque converter clutch to provide maximum improvement in isolation at low speed where vibration levels generally are the highest. The CPA is tuned for the dominate firing order of the engine, thus tracking the engine excitation at all operating speeds. Vehicle measurements are presented for both absorber types compared to current state of the art torque converter isolator technology.
2011-05-17
Technical Paper
2011-01-1556
Thomas Wellmann, Kiran Govindswamy, Georg Eisele
It is important to develop powertrain NVH characteristics with the goal of ultimately influencing/improving the in-vehicle NVH behavior since this is what matters to the end customer. One development tool called dB(VINS) based on a process called Vehicle Interior Noise Simulation (VINS) is used for determining interior vehicle noise based on powertrain level measurements (mount vibration and radiated noise) in combination with standardized vehicle transfer functions. Although this method is not intended to replace a complete transfer path analysis and does not take any vehicle specific sensitivity into account, it allows for powertrain-induced interior vehicle noise assessments without having an actual test vehicle available. Such a technique allows for vehicle centric powertrain NVH development right from an early vehicle development stage.
2011-05-17
Technical Paper
2011-01-1557
Ioannis Nerantzis, Emmanouil Athanasopoulos, Athanassios Mihailidis, Stephanos Theodossiades
Vehicle handling is heavily influenced by the torque distribution to the driving wheels. This work presents a newly developed differential, designed to actively control the driving torque distribution to the wheels. The new device incorporates an electric machine, which can operate either as a motor or generator. A control unit monitors signals from various sources in the vehicle, such as steering angle, yaw acceleration and wheel rotational speed. Then, a control algorithm takes into account the steering angle rate and the vehicle speed in order to determine the suitable difference between output torque values. The handling improvement capabilities are evaluated by simulating in ADAMS/Car the driving behavior of a vehicle equipped with the new differential. The model that has been used to simulate vehicle handling is that of a Formula SAE type racing car.
2011-05-17
Journal Article
2011-01-1558
Haris Ligata, Habib Rehman, James Rutter, Jason Ley
In this paper, the results of the experimental study are presented to describe the impact of several gear design and manufacturing related factors on NVH performance of a transfer case operating in 4-Lo mode. The investigated gear design factors include lead crowning and profile crowning of the planet gears. The influence of manufacturing and assembly is investigated by varying carrier pinhole tangential position error and carrier pinhole tangential tilt error. The experimental DOE study is performed on chassis dynamometer by using actual vehicle. The strategically placed accelerometers and microphones are used for data acquisition. The results show that, among the gear design related factors, lead modification has larger influence on the NVH performance than profile modification. The study also shows how manufacturing errors influence NVH performance of the transfer case by causing lead misalignment of gears and unequal planet load sharing.
2011-05-17
Technical Paper
2011-01-1559
X. Hua, J. Liu, D. W. Herrin, T. Elnady
This paper documents a finite element approach to predict the attenuation of muffler and silencer systems that incorporate diesel particulate filters (DPF). Two finite element models were developed. The first is a micro FEM model, where a subset of channels is modeled and transmission matrices are determined in a manner consistent with prior published work by Allam and Åbom. Flow effects are considered at the inlet and outlet to the DPF as well as viscous effects in the channels themselves. The results are then used in a macro FEM model of the exhaust system where the transmission relationship from the micro-model is used to simulate the DPF. The modeling approach was validated experimentally on an example in which the plane wave cutoff frequency was exceeded in the chambers upstream and downstream to the DPF.
2011-05-17
Technical Paper
2011-01-1560
Giancarlo Chiatti, Erasmo Recco, Ornella Chiavola
The optimization of the combustion process in diesel engines is one of the challenges to improve performance, emissions, fuel consumption and NVH characteristics. This work constitutes one of the last steps of a comprehensive research program in which vibration sensors are used with the purpose of developing and setting up a methodology that is able to monitor and optimize the combustion process by means of non-intrusive measurements. Previously published results have demonstrated the direct relationship that exists between in-cylinder pressure and engine block vibration signals, as well as the sensitivity of the engine surface vibration to variation of injection parameters when the accelerometer is placed in a sensitive location of the engine block.
2011-05-17
Technical Paper
2011-01-1561
George Bailey, Douglas Fussner
Geartrain noise can be a significant contribution to the overall sound level of diesel engines. Some engine manufacturers employ isolation solutions such as sound deadening covers and foam panels to combat the problem, but these add cost. Little has been published on geartrain noise reduction, and public standards for diesel geartrain design and development are not available. This paper describes an experimental study of the relative influence of gear design parameters on the rattle noise of a diesel engine timing geartrain. The geartrains of several diesel engines were benchmarked to determine the noise reduction strategies employed. A total of three gear sets were designed and tested in a 3.3L four cylinder normally aspirated diesel engine. The experimentation quantified the influence of an anti backlash idler gear in reducing gear rattle noise, and revealed that a key path for gear rattle noise transmission is through an idler gear journal bearing shaft.
2011-04-12
Journal Article
2011-01-1386
Mark Sellnau, James Sinnamon, Kevin Hoyer, Harry Husted
A single-cylinder engine was used to study the potential of a high-efficiency combustion concept called gasoline direct-injection compression-ignition (GDCI). Low temperature combustion was achieved using multiple injections, intake boost, and moderate EGR to reduce engine-out NOx and PM emissions engine for stringent emissions standards. This combustion strategy benefits from the relatively long ignition delay and high volatility of regular unleaded gasoline fuel. Tests were conducted at 6 bar IMEP - 1500 rpm using various injection strategies with low-to-moderate injection pressure. Results showed that triple injection GDCI achieved about 8 percent greater indicated thermal efficiency and about 14 percent lower specific CO2 emissions relative to diesel baseline tests on the same engine. Heat release rates and combustion noise could be controlled with a multiple-late injection strategy for controlled fuel-air stratification. Estimated heat losses were significantly reduced.
2011-04-12
Technical Paper
2011-01-1385
Yi Ren, Xianguo Li
The importance of using biodiesel as an alternative in diesel engines has been demonstrated previously. A reduction in the soot, CO and HC emissions and an increase in the NO emission burning biodiesel fuels were reported consistently in previous technical papers. However, a widely accepted NO formation mechanism for biodiesel-fueled engines is currently lacking. As a result, in past multi-dimensional simulation studies, the NO emission of biodiesel combustion was predicted unsatisfactorily. In this study, the interaction between the soot and NO formations is considered during the prediction of the soot and NO emissions in a biodiesel-fueled engine. Meanwhile, a three-step soot model and an eight NO model which includes both the thermal NO mechanism and prompt mechanism are implemented.
2011-04-12
Technical Paper
2011-01-1389
Kihyun Kim, Sangwook Han, Choongsik Bae
Mode transition between low temperature combustion and conventional combustion was investigated in a direct injection diesel engine. Low temperature diesel combustion was realized by means of high exhaust gas recirculation rate (69~73%) and early injection timing (-28~ -16 crank angle degree after top dead center) compared with those (20% exhaust gas recirculation rate and -8 crank angle degree after top dead center) of conventional combustion. Tests were carried out at different engine speeds and injection pressures. Exhaust gas recirculation rate was changed transiently by controlling each throttle angle for fresh air and exhaust gas recirculation to implement mode transition. Various durations for throttle transition were applied to investigate the effect of speed change of exhaust gas recirculation rate on the characteristics of mode transition.
2011-04-12
Technical Paper
2011-01-1388
Andrew Smallbone, Amit Bhave, Aaron R. Coble, Sebastian Mosbach, Markus Kraft, Robert McDavid
In recent decades, “physics-based” gas-dynamics simulation tools have been employed to reduce development timescales of IC engines by enabling engineers to carry out parametric examinations and optimisation of alternative engine geometry and operating strategy configurations using desktop PCs. However to date, these models have proved inadequate for optimisation of in-cylinder combustion and emissions characteristics thus extending development timescales through additional experimental development efforts. This research paper describes how a Stochastic Reactor Model (SRM) with reduced chemistry can be employed to successfully determine in-cylinder pressure, heat release and emissions trends from a diesel fuelled engine operated in compression ignition direct injection mode using computations which are completed in 147 seconds per cycle.
2011-04-12
Technical Paper
2011-01-1382
Wenbin Yu, Bin Liu, Yang Li, Qingpeng Su, Yiqiang Pei, Wanhua Su
Combustion control strategy for high efficiency and low emissions in a heavy duty (H D) diesel engine was investigated experimentally in a single cylinder test engine with a common rail fuel system, EGR (Exhaust Gas Recirculation) system, boost system and retarded intake valve closing timing actuator. For the operation loads of IMEPg (Gross Indicated Mean Effective Pressure) less than 1.1 MPa the low temperature combustion (LTC) with high rate of EGR was applied. The fuel injection modes of either single injection or multi-pulse injections, boost pressure and retarded intake valve closing timing (RIVCT) were also coupled with the engine operation condition loads for high efficiency and low emissions. A higher boost pressure played an important role in improving fuel efficiency and obtaining ultra-low soot and NOx emissions.
2011-04-12
Journal Article
2011-01-1381
Ezio Mancaruso, Luigi Sequino, Bianca Maria Vaglieco, Claudio Ciaravino, Alberto Vassallo
The present paper describes the results of a cooperative research project between GM Powertrain Europe and Istituto Motori - CNR aimed at studying the impact of both fresh and highly oxidized RME at two levels of blending on spray formation and combustion in modern automotive diesel engines. The tests were performed on an optical single-cylinder engine sharing combustion system configuration with the 2.0L Euro5 GM diesel engine for passenger car application. Two blends (B50 and B100) blending were tested for both fresh and aged RME and compared with commercial diesel fuel in two different operating points typical of NEDC (1500rpm/2bar BMEP and 2000rpm/5bar BMEP). The experimental activity was devoted to an in-depth investigation of the spray density, breakup and penetration, mixture formation, combustion and soot formation, by means of optical techniques.
2011-04-12
Journal Article
2011-01-1384
Michael J. Tess, Chang-Wook Lee, Rolf D. Reitz
Several diffusion combustion scaling models were experimentally tested in two geometrically similar single-cylinder diesel engines with a bore diameter ratio of 1.7. Assuming that the engines have the same in-cylinder thermodynamic conditions and equivalence ratio, the combustion models primarily change the fuel injection pressure and engine speed in order to attain similar performance and emissions. The models tested include an extended scaling model, which scales diffusion flame lift-off length and jet spray penetration; a simple scaling model, which only scales spray penetration at equal mean piston speed; and a same speed scaling model, which holds crankshaft rotational velocity constant while also scaling spray penetration. Successfully scaling diffusion combustion proved difficult to accomplish because of apparent differences that remained in the fuel-air mixing and heat transfer processes.
2011-04-12
Journal Article
2011-01-1383
Clément Chartier, Oivind Andersson, Bengt Johansson, Mark Musculus, Mohan Bobba
Post-injection strategies aimed at reducing engine-out emissions of unburned hydrocarbons (UHC) were investigated in an optical heavy-duty diesel engine operating at a low-load, low-temperature combustion (LTC) condition with high dilution (12.7% intake oxygen) where UHC emissions are problematic. Exhaust gas measurements showed that a carefully selected post injection reduced engine-out load-specific UHC emissions by 20% compared to operation with a single injection in the same load range. High-speed in-cylinder chemiluminescence imaging revealed that without a post injection, most of the chemiluminescence emission occurs close to the bowl wall, with no significant chemiluminescence signal within 27 mm of the injector. Previous studies have shown that over-leaning in this near-injector region after the end of injection causes the local equivalence ratio to fall below the ignitability limit.
2011-04-12
Technical Paper
2011-01-1395
Cody William Squibb, Harold Schock, Thomas Stuecken, Mulyanto Poort, Kyle Crayne, Charles Gray, Fakhri Hamady
This work presents a method for simultaneously capturing visible and infrared images along with pressure data in an optical Diesel engine based on the International 4.5L VT275 engine. This paper seeks to illustrate the merits of each imaging technique for visualizing both in-cylinder fuel spray and combustion. The engine was operated under a part load, high simulated exhaust gas recirculation operating condition. Experiments examining fuel spray were conducted in nitrogen. Overlays of simultaneously acquired infrared and visible images are presented to illustrate the differences in imaging between the two techniques. It is seen that the infrared images spatially describe the fuel spray, especially fuel vapors, and the fuel mixing process better than the high-speed visible images.
2011-04-12
Technical Paper
2011-01-1394
Carl Magnus Lewander, Bengt Johansson, Per Tunestal
Partially Premixed Combustion (PPC) is a combustion concept by which it is possible to get low smoke and NOx emissions simultaneously. PPC requires high EGR levels to extend the ignition delay so that air and fuel mix prior to combustion to a larger extent than with conventional diesel combustion. This paper investigates the operating region of single injection PPC for three different fuels; Diesel, low octane gasoline with similar characteristics as diesel and higher octane standard gasoline. Limits in emissions are defined and the highest load that fulfills these requirements is determined. The investigation shows the benefits of using high octane number fuel for Multi-Cylinder PPC. With high octane fuel the ignition delay is made longer and the operating region of single injection PPC can be extended significantly. Experiments are carried out on a multi-cylinder heavy-duty engine at low, medium and high speed.
2011-04-12
Technical Paper
2011-01-1397
Vladimir Marcov, Sergey Gladyshev, Sergey Devianin
Parameters of the fuel economy and the exhaust gases pollution of the high-speed diesel engines, with unshared and half-shared combustion chambers, are predetermined by processes of fuel spray and fuel-air mixture creation. The parameters of these processes (fuel spraying and development of flame structure dynamic) appreciably depend from design features of a flowing part of the injector tips. The major parameters of the injector tips design are the spraying nozzles length and the ratio of the length these nozzles to their diameters. The experimental research of the D-245.12C type diesel engine has been carried out. Fuel injectors of the diesel engine were equipped with injector tips of different spray nozzles lengths. The experimental data show improvement fuel efficiency, reduction of emissions and smoke due to optimization of geometries in the injector tip.
2011-04-12
Technical Paper
2011-01-1396
Yingying Lu, Wenbin Yu, Wanhua Su
The Premixed Charge Compression Ignition (PCCI) engine has the potential to reduce soot and NOx emissions while maintaining high thermal efficiency at part load conditions. However, several technical barriers must be overcome. Notably ways must be found to control ignition timing, expand its limited operation range and limit the rate of heat release. In this paper, comparing with single fuel injection, the superiority of multiple-pulse fuel injection in extending engine load, improve emissions and thermal efficiency trade-off using high exhaust gas recirculation (EGR) and boost in diesel PCCI combustion is studied by engine experiments and simulation study. It was found that EGR can delay the start of hot temperature reactions, reduce the reaction speed to avoid knock combustion in high load, is a very useful method to expand high load limit of PCCI. EGR can reduce the NOx emission to a very small value in PCCI.
2011-04-12
Technical Paper
2011-01-1391
Philipp Adomeit, Markus Jakob, Andreas Kolbeck, Stefan Pischinger
The requirement of reducing worldwide CO₂ emissions and engine pollutants are demanding an increased use of bio-fuels. Ethanol with its established production technology can contribute to this goal. However, due to its resistive auto-ignition behavior the use of ethanol-based fuels is limited to the spark-ignited gasoline combustion process. For application to the compression-ignited diesel combustion process advanced ignition systems are required. In general, ethanol offers a significant potential to improve the soot emission behavior of the diesel engine due to its oxygen content and its enhanced evaporation behavior. In this contribution the ignition behavior of ethanol and mixtures with high ethanol content is investigated in combination with advanced ignition systems with ceramic glow-plugs under diesel engine relevant thermodynamic conditions in a high pressure and temperature vessel.
2011-04-12
Journal Article
2011-01-1390
Antonio Pires da Cruz, Jean-Pierre Dumas, Gilles Bruneaux
Soot Volume Fraction (SVF) measurements were performed in an IFP Energies nouvelles optical single cylinder Diesel engine operated in Low Temperature Combustion (LTC) conditions. The engine was equipped with a sapphire liner, a dedicated flat bowl piston and a six-hole common-rail high pressure injector. The piston design included four quartz windows allowing optical access into the bowl. The aim of this work was to study soot formation and oxidation during the LTC Diesel combustion process and to build a database providing soot formation and oxidation data under a set of engine conditions to help developing and testing Computational Fluid Dynamics (CFD) models. Two complementary optical diagnostic techniques were combined: Planar Laser Induced Incandescence (PLII) and Laser Extinction Method (LEM).
2011-04-12
Journal Article
2011-01-1393
Kazuhisa Inagaki, Jyunichi Mizuta, Takayuki Fuyuto, Takeshi Hashizume, Hirokazu Ito, Hiroshi Kuzuyama, Tsutomu Kawae, Masaaki Kono
A new clean diesel combustion concept has been proposed and its excellent performance with respect to gas emissions and fuel economy were demonstrated using a single cylinder diesel engine. It features the following three items: (1) low-penetrating and highly dispersed spray using a specially designed injector with very small and numerous orifices, (2) a lower compression ratio, and (3) drastically restricted in-cylinder flow by means of very low swirl ports and a lip-less shallow dish type piston cavity. Item (1) creates a more homogeneous air-fuel mixture with early fuel injection timings, while preventing wall wetting, i.e., impingement of the spray onto the wall. In other words, this spray is suitable for premixed charge compression ignition (PCCI) operation, and can decrease both nitrogen oxides (NOx) and soot considerably when the utilization range of PCCI is maximized.
2011-04-12
Journal Article
2011-01-1392
Marcis Jansons, Radu Florea, Kan Zha, Elena Florea
Misfiring or partial combustion during diesel engine operation results in the production of partial oxidation products such as ethylene (C₂H₄), carbon monoxide and aldehydes, in particular formaldehyde (HCHO). These compounds remain in the cylinder as residual gases to participate in the following engine cycle. Carbon monoxide and formaldehyde have been shown to exhibit a dual nature, retarding ignition in one temperature regime, yet decreasing ignition delay periods of hydrocarbon mixtures as temperatures exceed 1000°K. Largely unknown is the synergistic effects of such species. In this work, varying amounts of C₂H₄ and HCHO are added to the intake air of a naturally aspirated optical diesel engine and their combined effect on autoignition and subsequent combustion is examined. To observe the effect of these dopants on the low-temperature heat release (LTHR), ultraviolet chemiluminescent images are recorded using intensified CCD cameras.
2011-04-12
Technical Paper
2011-01-1379
Jose Desantes, Vicente Bermudez, Antonio Garcia, Waldemar Linares, Christopher Kolodziej
In-cylinder emission control strategies, such as modifications of injection pressure and injection timing, have been used by researchers in order to reduce exhaust emissions and to comply with the legislation standards. Since some years ago post-injections have been studied and are well known as being efficient for soot emissions reduction. Although is well known that diesel gaseous and particle mass emissions have been reduced progressively over the last twenty years in response to the restrictive emission legislation and due to the application of new technologies The aim of this work is to help develop and understand the effect of the post-injection on diesel exhaust particle size distributions. The approach is to use a modern, well instrumented research engine equipped with a flexible high pressure fuel injection system. The results of this work are available to help provide guidelines for strategies to achieve reductions of the particle size distributions in diesel engines.
2011-04-12
Technical Paper
2011-01-1376
Karl Bo Albert Mikkelsen, Steve Lambert
Electric energy storage is among the most significant hurdles to deployment of electric vehicles (EVs). Present storage methods struggle to provide the capacity and the service life demanded by automotive use. Hybrid energy storage systems (HESS) use a combination of storage types, for example, different types of batteries and ultracapacitors, to tailor the characteristics of the storage system to each application. In addition to sizing the system for the intended application, a suitable strategy for the integration of the energy storage system must be adopted. In the present application, a HESS has been designed for the electrification of a 2004 Chrysler Pacifica, through consideration of a combination of high capacity batteries, high power batteries, and capacitors. Hybrid storage systems using batteries alone, batteries and capacitors, and dual batteries have been considered.
2011-04-12
Technical Paper
2011-01-1372
Kosuke Oguri, Naoki Maruno
A battery module structure and a battery management system that is optimal for the structure were developed, in order to facilitate the work of equipping hybrid cars with lithium-ion batteries (LIBs) that are expected to improve vehicle performance. This paper describes the structure of the LIB and the battery management system that is optimal for it. The battery module structure has cells with a sturdy holding structure and a highly efficient cooling system. The structure has enabled the improvement of battery pack system power output by 80% per unit weight and by 20% per unit volume compared to the previous model. The optimal management system prevents battery overcharge by detecting and controlling the state of charge (SOC) of each cell with a high degree of accuracy.
2011-04-12
Technical Paper
2011-01-1420
Vittorio Ravaglioli, Davide Moro, Gabriele Serra, Fabrizio Ponti
In modern Diesel engine control strategies the guideline is to perform an efficient combustion control, mainly due to the increasing request to reduce pollutant emissions. Innovative control algorithms for optimal combustion positioning require the on-board evaluation of a large number of quantities. In order to perform closed-loop combustion control, one of the most important parameters to estimate on-board is MFB50, i.e. the angular position in which 50% of fuel mass burned within an engine cycle is reached. Furthermore, MFB50 allows determining the kind of combustion that takes place in the combustion chamber, therefore knowing such quantity is crucial for newly developed low temperature combustion applications (such as HCCI, HCLI, distinguished by very low NOx emissions). The aim of this work is to develop a virtual combustion sensor, that provides MFB50 estimated value as a function of quantities that can be monitored real-time by the Electronic Control Unit (ECU).
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