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Viewing 1 to 30 of 41055
2015-09-06
Technical Paper
2015-24-2385
Guillaume Alix, Jean-Charles Dabadie, Gregory Font
Legal constraints concerning CO2 emissions have made the improvement of light duty vehicle efficiency mandatory. In result, vehicle powertrain and its development have become increasingly complex, requiring the ability to assess rapidly the effect of several technological solutions, such as hybridization or internal combustion engine (or ICE) downsizing, on vehicle CO2 emissions. In this respect, simulation is nowadays a common way to estimate a vehicle’s fuel consumption on a given driving cycle. This estimation can be done with the knowledge of vehicle main characteristics, its transmission ratio and efficiency and its internal combustion engine (ICE) fuel consumption map. While vehicle and transmission parameters are relatively easy to know, the ICE consumption map has to be obtained through either test bench measurements or computation.
2015-09-06
Technical Paper
2015-24-2387
Emiliano Vitaliani, Daniele Di Rocco, Martin Sopouch
The aim of this paper is the study of the Centrifugal Pendulum Vibration Absorber (CPVA) dynamic behaviour, with the background of improved vibration isolation and damping quality through a wide range of operating speeds. The CPVAs are passive devices, which are used in rotating machinery to reduce the torsional vibration without decreasing performance. After a first use of these damping systems in the field of aeronautics, nowadays CPVAs are employed also in railway and automotive applications. In principle, the CPVA is a mass, mounted on a rotor, which moves along a defined path relative to the rotor itself, driven by centrifugal effects and by the rotor torsional vibrations. The advantage that such absorbers provide is the capability to counteract torsional vibrations arising with frequencies proportional to the mean operating speed. This is in particular the case with Internal Combustion Engines (ICE) where the induced vibrations are caused by the combustions process.
2015-09-06
Technical Paper
2015-24-2390
Shashi Aithal, Stefan Wild
Design and optimization of automotive engines present unique challenges on account of the large design space and conflicting constraints. Optimizing the fuel consumption and reducing emissions over a driving cycle is a good example. Inlet pressure, equivalence ratio, humidity, EGR fraction, inlet air temperature, ignition timing, engine load, engine speed (RPM) etc. each impact fuel consumption and emissions and thus represent a vast parametric space to conduct de sign and global optimization studies. This large parametric space is further increased when one has to consider newer fuels and fuel-blends (varying ratios of fuel-additive mixtures) further complicating the design-optimization problem. The large design parameter space precludes the use of detailed numerical or experimental investigations. Physics-based reduced-order models (quasi-dimensional models) can be used effectively in the design and global optimization of such problems.
2015-09-06
Technical Paper
2015-24-2392
Vincenzo De Bellis, Luigi Teodosio, Daniela Siano, Fabrizio Minarelli, Diego Cacciatore
In this paper, a high performance V12 spark-ignition engine is experimentally investigated at test-bench in order to fully characterize its behavior in terms of both average and cycle-by-cycle performance parameters, for different operating conditions. In particular, for each considered point, a spark advance sweep is actuated, starting from a knock-free calibration, up to intense knock operation. Trains of 300 consecutive pressure cycles are acquired for each of the 12 cylinders, together with the main overall engine performance, including air flow, fuel flow, torque, pollutant emissions, and fuel consumption. Acquired data are statistically analyzed to derive the distributions of main indicated parameters (combustion phasing and duration, Indicated Mean Effective Pressure - IMEP, etc.) in order to find proper correlation with averaged quantities, collecting the findings of all the considered operating points and all the cylinders.
2015-09-06
Technical Paper
2015-24-2410
Stefania Falfari, Claudio Forte, Gian Bianchi, Giulio Cazzoli, Cristian Catellani, Lucio Postrioti, Fabrizio Ottobre
In the next incoming future the necessity of reducing the raw emissions leads to the challenge of an increment of the thermal engine efficiency. In particular it is necessary to increase the engine efficiency not only at full load but also at partial load conditions. In the open literature very few technical papers are available on the partial load conditions analysis. In the present paper the analysis of the effect of the throttle valve rotational direction on the mixture formation is analyzed. The engine was a PFI 4-valves motorcycle engine. The engine geometry was formed by the intake duct and the cylinder. The throttle valve opening angle was 17.2 deg, which lays between the very partial load and the partial load condition. The CFD code adopted for the analysis was the FIRE AVL code v. 2013.2. The intake and the compression phases till TDC were simulated: inlet boundary conditions from 1D simulations were imposed.
2015-09-06
Technical Paper
2015-24-2402
Irufan Ahmed, Golnoush Ghiasi, A. Gnana Sagaya Raj, Nedunchezhian Swaminathan, Jann Koch, Karel Steurs, Yuri M. Wright
Three-dimensional Computational Fluid Dynamics (CFD) has become an integral part in analyzing engine in-cylinder processes since it provides detailed information on flow and combustion inside internal combustion engines, hence allowing for improvements during the development of modern engine concepts. The predictive capability of simulation tools depends largely on the accuracy, fidelity and robustness of the various model used, in particular concerning turbulence and combustion, and, in some cases, two-phase flow. Almost all combustion models currently used in engine design require some level of parameter tuning to obtain a reasonable match between measured and computed in-cylinder pressure evolution. However, if the model parameters are closely tied to the physics of the problem then one might be able to eliminate this model tuning, specifically for the combustion sub-modeling part.
2015-09-06
Technical Paper
2015-24-2406
Gyujin Kim, Kyoungdoug Min
Development of injection technologies such as common-rail direct injection allows multiple injection strategy in Diesel Engine, which can reduce emissions, noises and vibrations. Meanwhile, three dimensional combustion model using CFD can be a good apparatus to visualize the in-cylinder phenomena. RIF (Representative Interactive Flamelet) model shows a good prediction of non-premixed combustion. In RIF model, chemical time scales are considered to be smaller than those of turbulence, which can decouple the equations of heat and mass transfer from flow equations. Furthermore, theses governing equations can be described by one conserved scalar which is called mixture fraction by using the assumption that the flame is sufficient to thin in the direction orthogonal to the flame surface. However, its dependency on the mixture fraction set a limit on the combustion analysis for the single injection.
2015-09-06
Technical Paper
2015-24-2421
Federico Stola, Domenico Paolino, Marco Parotto, Fabio Troina
Current market drivers for automotive and light commercial engines and powertrain systems are mainly the new CO2 emission regulations all over the world and the pollutant emission reduction in the emerging markets, at minimal system cost. For both reasons, the adoption of a regulated electric low pressure fuel pump is very advantageous for electronically controlled diesel systems, customized for the emerging markets. Usually, the fuel delivery is performed at the maximum flow rate and a pressure regulator discharges the exceeding fuel amount from the rail or upstream the high pressure pump. At part load, the electric feed pump flow is higher than the request for engine power generation. For the purpose of this paper, the low pressure fuel pump is controlled for fuel delivery according to the engine request (reduced fuel consumption), thus avoiding the use of a pressure regulator valve (reduced cost).
2015-09-06
Technical Paper
2015-24-2428
Ferdinando Taglialatela Scafati, Francesco Pirozzi, Salvatore Cannavacciuolo, Luigi Allocca, Alessandro Montanaro
Future emission regulations require the development of gasoline combustion engines with improved efficiency in order to obtain, other than a strong reduction of the toxic emissions, also a reduction of fuel consumption and hence carbon dioxide emissions. The greatest fuel consumption benefit is achieved by means of systems such as the gasoline direct injection combustion with unthrottled lean stratified operation. In this mode, the fuel is injected later in the compression stroke allowing stable combustion of ultra-lean mixtures. However, use of gasoline stratified charges can lead to several problems. In particular, due to the excess oxygen in the combustion stroke, the NOx emission levels are generally higher than in a PFI engine or homogeneous charge direct injection. Moreover, short time for mixture preparation and spray wall impingements are responsible for high cycle-to-cycle variability and high particle emissions.
2015-09-06
Technical Paper
2015-24-2467
Alessandro Ferrari, Federica Paolicelli
The modal analysis of a Common Rail fuel injection system equipped with solenoid injectors of the latest generation has been performed in the frequency domain. A complete lumped parameter model of the high-pressure hydraulic circuit from the pump delivery to the injector nozzles has been realized and validated by comparison with the frequency modal values obtained by applying a peak-picking technique to the measured pressure time history. Three main modal motions have been identified in the considered injection apparatus and the possible resonances with the external forcing terms, i.e., pump delivered flow-rate, pressure control valve discharged flow-rate and flow-rates expelled by the solenoid injector, have been highlighted and discussed. Furthermore, a sensitivity analysis of the frequency domain performance to key geometrical features of the high-pressure system layout has been carried out.
2015-09-06
Technical Paper
2015-24-2468
Kar Mun Pang, Hiew Mun Poon, Hoon Kiat Ng, Suyin Gan, Jesper Schramm
This work concerns the modelling of soot formation process during n-dodecane and diesel spray combustion under engine-like conditions. The key aim is to investigate the effects of chemical kinetics on soot formation characteristics at different ambient temperatures. Numerical computation is performed using an open-source computational fluid dynamics software. Prior to simulating the diesel combustion, numerical models including a revised multi-step soot model is validated by comparing the experimental data of n-dodecane fuel in which the associated chemistry is better understood. In the diesel spray simulations, a single component n-heptane model and the multi-component Diesel Oil Surrogate (DOS) model which uses a reduced toluene sub-mechanism to represent the aromatic compound are adopted. The third mechanism used comprises skeletal chemical mechanisms of n-hexadecane and heptamethylnonane.
2015-09-06
Technical Paper
2015-24-2461
Agnese Magno, Ezio Mancaruso, Bianca Maria Vaglieco
The diesel engine is currently the most efficient internal combustion engine technology. Moreover, in order to realize more efficient engine type could be convenient to combine this technology with one of the cleanest fuels available (methane). The main benefits are: methane (CH4) is cheaper than diesel and thus may reduce fuel costs; and, dual fuel technology also reduces particulate matter emissions. In the present activity, dual fuel operation was investigated in a single cylinder research engine. Methane was injected in the intake manifold while the diesel was delivered via the standard injector directly into the engine. The aim is to study the effect of increasing methane concentration at constant injected diesel amount on the start of combustion, ignition delay, and combustion evolution.
2015-09-06
Technical Paper
2015-24-2466
Tim Lackmann, Alan kerstein, Michael Oevermann
To further improve engines in terms of both efficiency and emissions many new combustion concepts are currently being investigated. Examples include homogeneous charge compression ignition (HCCI), stratified charge compression ignition (SCCI), lean stratified premixed combustion, and high levels of exhaust gas recirculation (EGR) in diesel engines. All of these combustion concepts have in common that the typical combustion temperatures are lower than in traditional spark ignition or diesel engines. To further improve and to develop combustion concepts for clean and high efficient engines, it is necessary to develop new computational tools and combustion models which can be used under non-standard conditions such as low temperature combustion. In this study a regime-independent combustion modeling strategy for non-premixed combustion is used to simulate a spray combustion process. The name of the recently developed model is RILEM (Representative Interactive Linear Eddy Model).
2015-09-06
Technical Paper
2015-24-2464
Daniele Farrace, Ronny Panier, Martin Schmitt, Konstantinos Boulouchos, Yuri M. Wright
Large Eddy Simulations (LES) provide instantaneous values indispensable to conduct statistical studies of relevant fluctuating quantities for diesel sprays. However, numerous realizations are generally necessary for LES to derive statistically averaged quantities necessary for validation of the numerical framework by means of measurements and for conducting sensitivity studies, leading to extremely high computational efforts. In this context, the aim of this work is to explore and validate alternatives to the simulation of 20-50 single realizations at considerably lower computational costs, by taking advantage of the axisymmetric geometry and the Quasi-Steady-State (QSS) condition of the near nozzle flow at a certain time after start-of-injection (SOI).
2015-09-06
Technical Paper
2015-24-2438
Maria Founti, Yannis Hardalupas, Christopher Hong, Christos Keramiotis, Kumara Gurubaran Ramaswamy, Nikolaos Soulopoulos, Alexander Taylor, Dimitrios P. Touloupis, George Vourliotakis
Engine research is focused on fulfilling the demand for high performance and comfort levels, as well as to satisfy tough vehicular exhaust emission regulations. Diesel engines, in particular, dominate the land transportation sector and their performance optimization is essential. In this regard, novel, sophisticated operating modes incorporate a variety of combinations including multiple injection strategies and excessive exhaust gas recirculation (EGR). This diversion from traditional diesel combustion poses difficulties regarding engine control and load flexibility, necessitating fuel-engine synergies identification. Conventional diesel combustion is governed by fuel and air mixing and reaction rates, or in other words, by both kinetically- and mixing- controlled phases. Kinetically-controlled combustion schemes, such as partially-premixed, essentially restrain the diffusion phase, which is largely responsible for soot formation.
2015-09-06
Technical Paper
2015-24-2452
Benedikt Heuser, Sebastian Ahling, Florian Kremer, Stefan Pischinger, Hans Rohs, Bastian Holderbaum, Thomas Korfer
An experimental study has been carried out on dual-fuel operation with a Diesel engine for passenger car application. For these investigations, two very common fuels were chosen: For port fuel injection, the fuel used was gasoline (RON95, E10), for direct injection it was EN590 Diesel fuel. The experiments have been carried out almost in the whole engine load range from low part load at an indicated mean effective pressure (IMEP) of 0.43 MPa up to full load operation at an IMEP of 2.8 MPa. The engine speed was varied from 1500 rpm up to 4000 rpm. Within the relevant engine part load range, emissions of nitric oxides (NOx) were kept below the EU6 level at engine-out. At low part load, emissions of hydrocarbons (HC) and carbon monoxide (CO) as well as combustion stability are challenging in dual-fuel operation. Thus, the share of gasoline was limited to 60% m/m.
2015-09-06
Technical Paper
2015-24-2453
Abdul Rahman K, A Ramesh
Diesel fuelled HCCI (Homogeneous Charge Compression Ignition) engines experience advanced heat release rates and high HC emissions. However, gaseous fuel like biogas and hydrogen that have high self ignition temperatures have been used to effectively retard the combustion process in diesel fuelled HCCI engines. Since gaseous fuels form homogeneous mixtures more readily as compared to diesel they also can lower the HC and smoke emissions in HCCI engines. In biogas diesel HCCI engines the homogeneity of the diesel which is influenced by the injection process significantly affects combustion and performance. This work focuses on the influence of injecting diesel in two pulses in a Biogas Diesel HCCI (BDHCCI) engine as against injecting it in a single pulse. Comparisons have also been made with the Dual Fuel mode of operation at the same output under different biogas to diesel energy ratios.
2015-09-06
Technical Paper
2015-24-2400
Andrea Matrisciano, Anders Borg, Cathleen Perlman, Harry Lehtiniemi, Michal Pasternak, Fabian Mauss
In this work we present a soot source term tabulation strategy for soot predictions under Diesel engine conditions within the zero-dimensional Direct Injection Stochastic Reactor Model (DI-SRM) framework. The DI-SRM accounts for detailed chemistry, in-homogeneities in the combustion chamber and turbulence-chemistry interactions. The previously developed method [1] was extended with a framework facilitating the use of tabulated soot source terms. The implementation allows for using soot source terms provided by an online chemistry calculation, and for the use of a pre-calculated flamelet soot source term library. Diesel engine calculations were performed using the same detailed kinetic soot model in both configurations. The chemical mechanism for n-heptane used in this work is taken from Zeuch et al. [2] and consists of 121 species and 973 reactions including PAH and thermal NO chemistry. The engine case presented in [1] is used also for this work.
2015-09-06
Technical Paper
2015-24-2460
Gabriele Di Blasio, Giacomo Belgiorno, Carlo Beatrice, Valentina Fraioli, Marianna Migliaccio
An increasing interest in the use of Natural Gas (NG) in CI engines is currently taking place, due to several reasons: it is cheaper than conventional Diesel fuel, permits a significant reduction in the amount of emitted carbon dioxide and is intrinsically cleaner, being much less prone to soot formation. In this respect, the Dual Fuel (DF) concept has already proven to be a viable solution, industrially implemented for several applications in the high duty engines category. Despite this, some issues still require a technological solution, preventing the commercialization of DF engines in wider automotive fields: the release of high amounts of unburned species, the risk of engine knock, the possible thermal efficiency reduction are some factors regarding the fuel combustion aspect. As know, one of the most important design parameter affecting emission and performance is the compression ratio (CR).
2015-09-06
Technical Paper
2015-24-2511
Theodoros Grigoratos, Georgios Fontaras, Giorgio Martini, Cesare Pelleto
Gas operated Heavy Duty Vehicles (HDV) powered by Natural Gas (NG) are seen as a possible option for curbing CO2 emissions, fuel consumption and operating costs of goods transport. Initiatives have been adopted by various organizations worldwide in order to introduce NG fueled HDVs in their fleets. In this study, an advanced newly designed CNG prototype engine, which was developed in the framework of the FP7 research project “CO2 Reduction for long distance transport” (CO2RE), is benchmarked against its parent Euro V compliant CNG engine (reference) in terms of emissions and fuel consumption. The main technological innovation includes a new cylinder head equipped with a Variable Valve Actuation system designed to provide on the intake side a continuous fully flexible variation of the valve lift and timing. The newly developed engine was optimized for urban emission profiles and operation such as garbage collection purposes.
2015-09-06
Technical Paper
2015-24-2512
Barouch Giechaskiel, Alessandro Zardini, Giorgio Martini
In 2009 a particle number (PN) limit was introduced in the European Union vehicle exhaust legislation for diesel passenger cars. The PN method requires measurement of solid particles (i.e. those that do not evaporate at 350°C) above 23 nm. In 2013 the same approach was introduced in the heavy duty engines legislation. The same approach will be added for gasoline direct injection vehicles from 2017. This decision was based on a long evaluation that concluded that there is no significant sub23nm fraction for this technology. In this paper we examine the suitability of the current PN method for mopeds and motorcycles. Emission levels of >10 mopeds and motorcycles are presented. Special attention is given to sub23nm emission levels for some of them. The investigation was conducted with PN legislation compliant systems with counters measuring above 23nm and 10nm.
2015-09-06
Technical Paper
2015-24-2515
Christophe Barro, Sushant Pandurangi, Philipp Meyer, Konstantinos Boulouchos, Philipp Elbert, Yuri M. Wright
Past research has shown that post injections have the potential to reduce Diesel engine exhaust PM concentration without any significant influence in NOx emissions. However, an accurate, widely applicable rule of how to parameterize a post injection such that it provides a maximum reduction of PM emissions does not exist. Moreover, the underlying mechanisms are not thoroughly understood. In past research, the underlying mechanisms have been investigated in engine experiments, in constant volume chambers and also using detailed 3D CFD-CMC simulations. It has been observed that soot reduction due to a post injection is mainly due to two reasons: increased turbulence from the post injection during soot oxidation and lower soot formation due to lower amount of fuel in the main combustion at similar load conditions. Those studies do not show a significant temperature rise caused by the post injection.
2015-09-06
Technical Paper
2015-24-2514
Marco Piumetti, Samir Bensaid, Nunzio Russo
A set of nanostructured CeO2-based catalysts with different topological and textural properties (CeO2-nanocubes, CeO2-nanocubes over ZSM-5-type zeolite, CeO2-nanorods, mesoporous CeO2 and CeO2-SCS) has been prepared to investigate the shape-dependency activity of ceria towards soot combustion under different reaction. The physico-chemical properties of the prepared materials have been studied using complementary techniques. The best performances, in terms of the total oxidation of soot, have been achieved for the CeO2-nanocubes, due to the abundance of coordinative unsaturated atomic sites on the exposed surfaces. However, better results, in terms of the onset of soot oxidation, have been obtained for high-surface-area materials, thus reflecting the key role of surface area at low temperatures. Activity tests have suggested the surface-sensitivity of soot oxidation over the prepared ceria-based materials, when the reaction temperature was above 410 °C or 370 °C.
2015-09-06
Technical Paper
2015-24-2516
Panayotis Dimopoulos Eggenschwiler, Daniel Schreiber
Particulate matter (PM)in diesel exhaust is captured in diesel particulate filters (DPFs). Since increased PM load in the filter and thus increased pressure drop across the filter deteriorates the engine performance, the filter load of the DPF has to be removed during a process referred to as regeneration. Measures for successful regeneration aim at accelerating soot oxidation and increase fuel consumption. Regeneration lay-out and thus fuel consumption increase is strongly depending on the oxidation behavior of soot. The aim of the present study is the investigation of soot oxidation characteristics. Therefore particle filters have been loaded with soot using the exhaust gas of small heavy duty vehicle operated under defined conditions on an engine dynamometer. The particle filters have been then dismantled and fragmented on their constituting segments. Each filter segment has been regenerated individually in a specifically designed test bench.
2015-09-06
Technical Paper
2015-24-2519
Richard Cornwell, Huntly Thomas, Joshua Dalby, Phil Carden, Brian Knight, Andrew Ward, Grace Carr
Fuel consumption, and the physical behaviours behind it, have never been of greater interest to the automotive engineering community. The enormous design, development and infrastructure investment involved with a new engine family which will be in production for many years demands significant review of the base engine fundamental architecture. Future CO2 challenges are pushing car manufacturers to consider alternative engine configurations. As a result, a wide range of diesel engine architectures are available in production particularly in the 1.4 to 1.6L passenger car market, including cylinder size, number of valves per cylinder, and bore:stroke ratio. In addition, the 3 cylinder engine has recently entered the market, despite its historic NVH concerns. Ricardo has performed a generic architecture study for a midsize displacement engine in order to assess the pros and cons of each engine configuration.
2015-09-06
Technical Paper
2015-24-2520
Simona Silvia Merola, Adrian Irimescu, Gerardo Valentino, Cinzia Tornatore, Stefano Silva, Alberto Grimaldi, Eugenio Carugati
A plasma ignition system was tested in a GDI engine with the target of combustion efficiency improvement without modifying the engine configuration. The plasma was generated by spark discharge and successively sustained to enhance its durability and practicality. Basically, plasma ignition was used to improve the initial combustion period and to reduce the fuel consumption and indicated mean effective pressure (IMEP) cyclic variation. The system was tested in an optically accessible single-cylinder DI SI engine to investigate the effects of plasma on kernel stability and flame front propagation under low loads and lean mixtures. The engine was equipped with the head of a commercial turbocharged engine with similar geometrical specifications (bore, stroke, compression ratio). All experiments were performed at 2000 rpm and 100 bar injection pressure.
2015-09-06
Technical Paper
2015-24-2523
Calogero Avola, Colin Copeland, Tomasz Duda, Richard Burke, Sam Akehurst, Chris Brace
The adoption of two stage serial turbochargers in combination with internal combustion engines can improve the overall efficiency of powertrain systems. In conjunction with the increase of engine volumetric efficiency, two stage boosting technologies are capable of increasing torque and pedal response of small displacement engines. In two stage serial turbocharges, a high pressure (HP) and a low pressure (LP) turbocharger are connected by a series of ducts. The former can increase charge pressure for low air mass flow typical of low engine speed. The latter has a bigger size and can cooperate with higher mass flows. In serial configuration, turbochargers are packaged in a way that the exhaust gases access the LP turbine after exiting the HP turbine. On the induction side, fresh air is compressed sequentially by LP and HP compressors. By-pass valves and waste-gated turbines are often included in two stage boosting systems in order to regulate turbochargers operations.
2015-09-06
Technical Paper
2015-24-2524
José Lujan, José V. Pastor, Héctor Climent, Manuel Rivas
On actual gasoline turbocharged engines it is common to use a compressor by-pass valve in order to solve the compressor surge problem when the throttle pedal position is released and closes rapidly. The paper deals with a methodology based on experiments to measure the discharge coefficient of an integrated compressor by-pass valve, to understand the possible difference between the steady flow test bench and turbocharger test bench discharge coefficient measurements. To determine if there is some compressor outlet flow field influence due to compressor blades rotation that could modify the discharge coefficient measurement, compared to the steady flow test bench measurements, a fully instrumented turbocharger was used to measure the difference between steady flow test bench and turbocharger test bench discharge coefficients results. Effects of different boundary conditions on turbocharger test bench tests and how they affect the discharge coefficient measurement are also presented.
2015-09-06
Technical Paper
2015-24-2529
Riccardo Russo, Salvatore Strano, Mario Terzo
The yaw moment control systems are adopted in order to enhance the handling and to prevent the vehicle unstable behaviour. They can be substantially divided in three sub-categories: systems based on differential braking, systems based on the controlled torque distribution, and steer by wire systems. With reference to the torque distribution systems, they are substantially characterized by limited slip differentials able to generate an internal locking torque that allows to differentiate the output torque and to generate a corrective yaw moment on the vehicle. This paper deals with a new automotive controllable differential for the control of the yaw moment of the vehicle. Software simulations are presented in order to evaluate the benefits reachable by means of the proposed device. The device is based on the employment of magnetorheological fluid, whose magnetization allows to generate the locking torque and, consequently, the improving yaw moment.
2015-09-06
Technical Paper
2015-24-2526
Borislav Klarin, Thomas Resch, Chiara Sessarego, Giorgio Spanu, Gianni Lamonaca
Modern engines with low number of cylinders (I4, I3, I2) are typically equipped with a mass balancing unit to reduce free mass forces and moments and to keep powerunit vibrations, transferred via the mounts into the chassis, on an acceptable level and by that meet the required comfort quality. Typical disadvantages of mass balancing systems are increased friction, which reduces the engine efficiency, but also space, costs, increased complexity and negative effect on the engine acoustics. Especially the latter is defined by the design of the drive for the balancer unit. In many cases, this is realized by a gear drive, directly driven from the crankshaft. Therefore, special care has to be taken for the layout of this gear(s) to avoid potential rattle, gear tooth failure and negative noise transfer from gear contact to the housing structure (e.g. increased axial excitation due to selection of helix angle).
Viewing 1 to 30 of 41055