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Viewing 1 to 30 of 159
2014-10-13
Technical Paper
2014-01-2735
Alessandro Ferrari, Pietro Pizzo, Federica Paolicelli
Abstract A numerical-experimental analysis of a new generation Common Feeding (CF) fuel injection system, equipped with last generation solenoid injectors that feature pressure-balanced pilot-valves, has been developed. The main feature of the CF system is that it removes the accumulator from the high-pressure layout of the standard Common Rail (CR). In the CF apparatus, the high-pressure pump is connected directly to the injectors, and a small accumulation volume is integrated in the pump high-pressure circuit. The hydraulic performance of the CF system, including the injectors with the pressure-balanced pilot-valve, has been compared with that of the standard CR system in terms of injected masses, fuel leakages, high-pressure and injected flow-rate time histories. A previously developed advanced one-dimensional code for CR type systems has been adapted for the simulation of the CF high-pressure layout. Furthermore, electromagnetic, hydraulic and mechanical submodels have been set up for the pressure-balanced pilot-valve simulation.
2014-05-05
Technical Paper
2014-01-9046
Roberto Finesso, Ezio Spessa
Feed-forward low-throughput models have been developed to predict MFB50 and to control SOI in order to achieve a specific MFB50 target for diesel engines. The models have been assessed on a GMPT-E Euro 5 diesel engine, installed at the dynamic test bench at ICEAL-PT (Internal Combustion Engine Advanced Laboratory at the Politecnico di Torino) and applied to both steady state and transient engine operating conditions. MFB50 indicates the crank angle at which 50% of the fuel mass fraction has burned, and is currently used extensively in control algorithms to optimize combustion phasing in diesel engines in real-time. MFB50 is generally used in closed-loop combustion control applications, where it is calculated by the engine control unit, cycle-by-cycle and cylinder by-cylinder, on the basis of the measured in-cylinder pressure trace, and is adjusted in order to reduce the fuel consumption, combustion noise and engine-out emissions. A feed-forward approach has been developed in this paper.
2014-04-01
Technical Paper
2014-01-1070
Federico Millo, Luciano Rolando, Enrico Pautasso, Emanuele Servetto
Abstract In this paper a novel approach to mimic through numerical simulation Cycle-to-Cycle Variations (CCV) of the combustion process of Spark Ignition (SI) engines is described. The proposed methodology allows to reproduce the variability in combustion which is responsible for knock occurrence and thus to replicate the stochastic behavior of this abnormal combustion phenomenon. On the basis of the analysis of a comprehensive database of experimental data collected on a typical European downsized and turbocharged SI engine, the proposed approach was demonstrated to be capable to replicate in the simulation process the same percentage of knocking cycles experimentally measured in light-knock conditions, after a proper calibration of the Kinetics-Fit (KF), a new phenomenological knock model which was recently developed by Gamma Technologies. Finally, the capability of the proposed methodology, coupled with the usage of the KF knock model, to correctly identify the Knock Limited Spark Advance (KLSA) on the basis both of the CCV-replicating model and of a more traditional average-cycle simulation was assessed over a wide range of different operating conditions, thus confirming its reliability and robustness.
2014-04-01
Technical Paper
2014-01-1096
Daniela Anna Misul, Mirko Baratta, Hamed Kheshtinejad
Abstract Sustainable mobility has become a major issue for internal combustion engines and has led to increasing research efforts in the field of alternative fuels, such as bio-fuel, CNG and hydrogen addition, as well as into engine design and control optimization. To that end, a thorough control of the air-to-fuel ratio appears to be mandatory in SI engine in order to meet the even more stringent thresholds set by the current regulations. The accuracy of the air/fuel mixture highly depends on the injection system dynamic behavior and to its coupling to the engine fluid-dynamic. Thus, a sound investigation into the mixing process can only be achieved provided that a proper analysis of the injection rail and of the injectors is carried out. The present paper carries out a numerical investigation into the fluid dynamic behavior of a commercial CNG injection system by means of a 0D-1D code. The model has been validated by comparing the experimental readings to the numerical outputs in terms of injection system pressure profiles versus time.
2014-04-01
Technical Paper
2014-01-1050
Massimiliana Carello, Andrea Giancarlo Airale, Alessandro Ferraris
Abstract The use of composite materials is very important in automotive field to meet the European emission and consumption standards set for 2020. The most important challenge is to apply composite materials in structural applications not only in racing vehicles or supercars, but also in mass-production vehicles. In this paper is presented a real case study, that is the suspension wishbone arm (with convergence tie and pull-rod system) of the XAM 2.0 urban vehicle prototype, that it has the particular characteristics that the front and rear, and left and right suspension system has the same geometry. The starting point has been an existing solution made in aluminum to manufacture a composite one. The first step was the development of a dynamic model of the vehicle to understand the suspension loads and to define the suspension weight and stiffness target with respect to the solution made on aluminum, because it was necessary to understand the tensil strain on the component to simplify and optimize the geometry.
2014-04-01
Technical Paper
2014-01-0084
Mario Milanese, Ilario Gerlero, Carlo Novara
Abstract The vehicle sideslip angle is one of the most important variables for evaluating vehicle dynamics. The potential value of such a variable for obtaining significant improvements over current stability control systems is widely recognized. However, its direct measurement requires the use of complex and expensive devices which cannot be used in production cars. Large research efforts has been devoted to the problem of estimating the sideslip angle from other variables currently measured by standard Electronic Stability Control (ESC) sensors. However, at the best of author's knowledge, until now no application to production cars is known. In this paper, a new sideslip angle estimation technology is presented. Based on the innovative DVS methodology recently developed by the authors, a software algorithm, indicated as DVS/SA (Direct Virtual Sensor of Sideslip Angle), is designed, which estimates the sideslip angle from measurements of the yaw rate, lateral and longitudinal acceleration, wheel speed, steering angle, available from ESC sensors of most present production cars.
2014-04-01
Technical Paper
2014-01-1304
P.C. Bakker, J.E. De Abreu Goes, L.M.T. Somers, B.H. Johansson
The concept of Partially Premixed Combustion is known for reduced hazardous emissions and improved efficiency. Since a low-reactive fuel is required to extend the ignition delay at elevated loads, controllability and stability issues occur at the low-load end. In this investigation seven fuel blends are used, all having a Research Octane Number of around 70 and a distinct composition or boiling range. Four of them could be regarded as ‘viable refinery fuels’ since they are based on current refinery feedstocks. The latter three are based on primary reference fuels, being PRF70 and blends with ethanol and toluene respectively. Previous experiments revealed significant ignition differences, which asked for further understanding with an extended set of measurements. Experiments are conducted on a heavy duty diesel engine modified for single cylinder operation. In this investigation, emphasis is put on idling (600 rpm) and low load conditions. In particular, the so-called low-temperature heat release (LTHR) is studied.
2014-04-01
Technical Paper
2014-01-1798
Roberto Finesso, Ezio Spessa, Mattia Venditti
Abstract This paper describes the optimization of the layout and of the control strategy of through-the-road (TTR) parallel hybrid electric vehicles equipped with two compression-ignition engines that feature different values of maximum output power. First, a tool has been developed to define the optimal layout of each TTR vehicle. This is based on the minimization of the powertrain and fuel cost over a 10-year time span, taking into account the fuel consumption. Several performance requirements are guaranteed during the optimization, namely maximum vehicle velocity, 0-100 km/h acceleration time, gradeability and the all-electric range. A benchmark optimizer that is based on the dynamic programming theory has been developed to identify the optimal working mode and the gear number, which are the control variables of the problem. A mathematical technique, based on the pre-processing of a configuration matrix, has been developed in order to speed up the calculation time. After the layout optimization, the potential of the two identified hybrid vehicles in improving the fuel economy, compared with the conventional vehicle, has been analyzed and discussed over several driving missions, i.e., the New European Driving Cycle, the Artemis Urban Driving Cycle, the Artemis Rural Driving Cycle, the Artemis Motorway Driving Cycle and the Federal Test Procedure.
2013-11-27
Technical Paper
2013-01-2760
Eduardo Del Pozo de Dios, Juan Alba, Massimiliano avalle, Óscar cisneros, Alessandro scattina, Aritz esnaola
With electric vehicles becoming more and more popular, the classic “general purpose” vehicle concept is changing to a “dedicated vehicle” concept. Light trucks for goods delivery in cities are one of the examples. The European vehicle category L7e fits perfectly in the low power, low weight vehicle requirements for an electric light truck for goods delivery. However, the safety requirements of this vehicle category are very low and their occupants are highly exposed to injuries in the event of a collision. The European Commission co-funded project OPTIBODY (Optimized Structural components and add-ons to improve passive safety in new Electric Light Trucks and Vans) is developing a new structural concept based on a chassis, a cabin a several add-ons. The add-ons will provide improved protection in case of frontal, side and rear impact. Two mains issues also considered in both the chassis and the add-ons design were the crash compatibility and the interaction with the vulnerable road users.
2013-09-17
Technical Paper
2013-01-2160
Gevorg Baghdasaryan, Marine Mikilyan, Rafayel Saghoyan, Enrico Cestino, Giacomo Frulla
The stability analysis of plates and shells in high speed flow deals with the determination of the flutter instability boundary. A linear analysis is made using the basic principles of the theory of aero-elasticity of isotropic bodies, the theories of flexible plates, the stability equations and associated boundary conditions obtained through a linear formulation. Herein, the nonlinear stability of flexible plate immersed in a high speed gas flow is considered. The model takes into account quadratic and cubic aerodynamic nonlinearities as well as cubic geometric nonlinearities. It is shown that the inclusion of quadratic aerodynamic nonlinear components can lead to the appearance of “amplitude-frequency” phenomena in both the pre-critical as well as in the post-critical flow speed regimes. The influence of the free stream flow speed on the “amplitude-frequency” dependence phenomena is also presented.
2013-09-17
Technical Paper
2013-01-2207
Michele Cencetti, Laura Mainini, Paolo Maggiore
A Multi-Objective Optimization (MOO) problem concerning the thermal control problem of Multifunctional Structures (MFSs) is here addressed. In particular the use of Multi-Objective algorithms from an optimization tool and Self-Organizing Maps (SOM) is proposed for the identification of the optimal topological distribution of the heating components for a multifunctional test panel, the Advanced Bread Board (ABB). MFSs are components that conduct many functions within a single piece of hardware, shading the clearly defined boundaries that identify traditional subsystems. Generally speaking, MFSs have already proved to be a disrupting technology, especially in aeronautics and space application fields. The case study exploited in this paper refers to a demonstrator breadboard called ABB. ABB belongs to a particular subset of an extensive family of MFS, that is, of thermo-structural panels with distributed electronics and a health monitoring network. The scope of this work is to speculate upon the ABB concept, by investigating further developments that could improve the design of this class of multifunctional structures.
2013-09-17
Technical Paper
2013-01-2265
Andras Nagy, Balazs Gati, Enrico Cestino, Piergiovanni Marzocca
In the development of High Altitude Long Endurance (HALE) UAVs and their control the flexibility of the wing must be taken into account. The wing of this type of UAVs, usually made of highly flexible composite materials, has high aspect ratio with significant bending-torsional deformation during flight. The NASA Helios, as an example, has tragically shown that wing deformation coupled with control and power operation can cause serious problem in flight, instability can suddenly occur and can be quite difficult to foresee. In this paper the mathematical description of a flexible wing multibody model is presented. It is suitable to simulate the effect of both structural flexibility and flight dynamics and maneuvering on the wing deformation, and can be used to help developing control strategies for air vehicles with highly deformable wings. The paper will present simulation results for a typical HALE (High Altitude Long Endurance) wing with control surfaces and the effect of flexibility on the flight dynamic will be explored.
2013-09-17
Technical Paper
2013-01-2158
Enrico Cestino, Giacomo Frulla, Piergiovanni Marzocca
The aeroelastic design of highly flexible wings, made of extremely light structures yet still capable of carrying a considerable amount of non-structural weights, requires significant effort. The complexity involved in such design demands for simplified mathematical tools based on appropriate reduced order models capable of predicting the accurate aeroelastic behaviour. The model presented in this paper is based on a consistent nonlinear beam model, capable of simulating the unconventional aeroelastic behaviour of flexible composite wings. The partial differential equations describing the wing dynamics are reduced to a dimensionless form in terms of three ordinary differential equations using a discretization technique, along with Galerkin's method. Within this approach the nonlinear structural model an unsteady indicial based aerodynamic model with dynamic stall are coupled. Only three degrees of freedom in edgewise, flapwise, and torsion, are needed to describe efficiently the dynamics of the wing and to evaluate the sensitivity to system parameters, such as stiffness ratio, aspect ratio, and root angle of attack.
2013-09-17
Technical Paper
2013-01-2263
Mario Cassaro, Manuela Battipede, Piergiovanni Marzocca, Enrico Cestino, Aman Behal
The aim of this work is to apply an innovative adaptive ℒ1 techniques to control flutter phenomena affecting highly flexible wings and to evaluate the efficiency of this control algorithm and architecture by performing the following tasks: i) adaptation and analysis of an existing simplified nonlinear plunging/pitching 2D aeroelastic model accounting for structural nonlinearities and a quasi-steady aerodynamics capable of describing flutter and post-flutter limit cycle oscillations, ii) implement the ℒ1 adaptive control on the developed aeroelastic system to perform initial control testing and evaluate the sensitivity to system parameters, and iii) perform model validation and calibration by comparing the performance of the proposed control strategy with an adaptive back-stepping algorithm. The effectiveness and robustness of the ℒ1 adaptive control in flutter and post-flutter suppression is demonstrated. Results and discussion will follow with pertinent conclusions and future outlooks.
2013-09-08
Technical Paper
2013-24-0057
Federico Millo, Sabino Luisi, Andrea Stroppiana, Fabio Borean
Two different modifications of the baseline cylinder head configuration have been designed and experimentally tested on a MultiAir turbocharged gasoline engine, in order to address the issue of the poor in-cylinder turbulence levels which are typical of the Early-Intake-Valve-Closing (EIVC) strategies which are adopted in Variable Valve Actuation systems at part load to reduce pumping losses. The first layout promotes turbulence by increasing the tumble motion at low valve lifts, while the second one allows the addition of a swirl vortex to the main tumble structure. The aim for both designs was to achieve a proper flame propagation speed at both part and full load. The experimental activity was initially focused on the part load analysis under high dilution of the mixture with internal EGR, which can allow significant further reductions in terms of pumping losses but, on the other hand, tends to adversely affect combustion stability and to increase cycle-to-cycle variations. All the three different configurations (baseline, enhanced tumble, enhanced swirl) were compared in terms of combustion duration and combustion stability for increasing levels of EGR.
2013-09-08
Technical Paper
2013-24-0160
Maurizio Andreata, Federico Millo, Fabio Mallamo, Davide Mercuri, Chiara Pozzi
Three different ceramic substrate materials (Silicon Carbide, Cordierite and Aluminum Titanate) for a Diesel Particulate Filter (DPF) for a European passenger car diesel engine have been experimentally investigated in this work. The filters were soot loaded under real world operating conditions on the road and then regenerated in two different ways that simulate the urban driving conditions, which are the most severe for DPF regeneration, since the low exhaust flow has a limited capability to absorb the heat generated by the soot combustion. The tests showed higher temperature peaks, at the same soot loading, for Cordierite and Aluminum Titanate compared to the Silicon Carbide, thus leading to a lower soot mass limit, which in turn required for these components a higher regeneration frequency with draw backs in terms of fuel consumption and lube oil dilution. On the other hand Cordierite and Aluminum Titanate could guarantee a lower thermal loss across the DPF, thus allowing the attainment of higher temperature levels and consequently of higher efficiencies of an SCR system placed downstream of the DPF.
2013-09-08
Technical Paper
2013-24-0081
Federico Millo, Rocco Fuso, Luciano Rolando, Jianning Zhao, Andrea Benedetto, Filippo Cappadona, Paolo Seglie
Nowadays the increasing demand for sustainable mobility has fostered the introduction of innovative propulsion systems also in the public transport sector in order to achieve a significant reduction of pollutant emissions in highly congested urban areas. Within this context this paper describes the development of the HYBUS, an environmental friendly hybrid bus for on-road urban transportation, which was jointly carried out by Pininfarina and Politecnico di Torino in the framework of the AMPERE project. The first prototype of the bus was built by integrating an innovative hybrid propulsion system featuring a plug-in series architecture into the chassis of an old IVECO 490 TURBOCITY. The bus is 12 meters long and has a capacity of up to 116 passengers in the original layout. The project relied on a modular approach where the powertrain could be easily customized for size and power depending on the specific application. Furthermore this flexibility could pave the way to a significant reduction of investment costs since it could allow the revamping of obsolete vehicles in the fleet of public transportation companies, extending their end of life.
2013-09-08
Technical Paper
2013-24-0044
Roberto Finesso, Ezio Spessa, Ezio Mancaruso, Luigi Sequino, Bianca Maria Vaglieco
An innovative quasi-dimensional multizone combustion model for the spray formation, combustion and emission formation analysis in DI diesel engines was assessed and applied to an optical single cylinder engine. The model, which has been recently presented by the authors, integrates a predictive non stationary 1D spray model developed by the Sandia National Laboratory, with a diagnostic multizone thermodynamic model. The 1D spray model is capable of predicting the equivalence ratio of the fuel during the mixing process, as well as the spray penetration. The multizone approach is based on the application of the mass and energy conservation laws to several homogeneous zones identified in the combustion chamber. A specific submodel is also implemented to simulate the dilution of the burned gases. Soot formation is modeled by an expression which derives from Kitamura et al.'s results, in which an explicit dependence on the local equivalence ratio is considered. The model was used to analyze low load (BMEP = 2 bar at 1500 rpm) and medium load (BMEP = 5 bar at 2000 rpm) operating conditions in an optical single cylinder engine sharing the combustion system configuration of the 2.0L Euro5 GM diesel engine for passenger car application.
2013-09-08
Technical Paper
2013-24-0128
Stefano D'Ambrosio, Alessandro Ferrari, Ezio Spessa, Lorenzo Magro, Alberto Vassallo
The integration of the exhaust manifold in the engine cylinder head has received considerable attention in recent years for automotive gasoline engines, due to the proven benefits in: engine weight diminution, cost saving, reduced power enrichment, quicker engine and aftertreatment warm-up, improved packaging and simplification of the turbocharger installation. This design practice is still largely unknown in diesel engines because of the greater difficulties, caused by the more complex cylinder head layout, and the expected lower benefits, due to the absence of high-load enrichment. However, the need for improved engine thermomanagement and a quicker catalytic converter warm-up in efficient Euro 6 diesel engines is posing new challenges that an integrated exhaust manifold architecture could effectively address. A recently developed General Motors 1.6L Euro 6 diesel engine has been modified so that the intake and exhaust manifolds are integrated in the cylinder head. Extensive CAD/CAE/CAM analyses have been employed in order to guide the design of the overall surface and the water cooling jacket that surround the exhaust manifold of the new engine version, and thus to be able to improve the low-frequency thermal fatigue resistance of the head.
2013-09-08
Technical Paper
2013-24-0012
Mirko Baratta, Roberto Finesso, Hamed Kheshtinejad, Daniela Misul, Ezio Spessa, Yixin Yang, Massimo Arcidiacono
An innovative 0D predictive combustion model for the simulation of the HRR (heat release rate) in DI diesel engines was assessed and implemented in a 1D fluid-dynamic commercial code for the simulation of a Fiat heavy duty diesel engine equipped with a Variable Geometry Turbocharger system, in the frame of the CORE (CO2 reduction for long distance transport) Collaborative Project of the European Community, VII FP. The 0D combustion approach starts from the calculation of the injection rate profile on the basis of the injected fuel quantities and on the injection parameters, such as the start of injection and the energizing time, taking the injector opening and closure delays into account. The injection rate profile in turn allows the released chemical energy to be estimated. The approach assumes that HRR is proportional to the energy associated with the accumulated fuel mass in the combustion chamber. This procedure allows an accurate calculation of different combustion parameters important for engine calibration, such as MFB50 (50% of fuel burned mass fraction crank angle).
2013-07-18
Article
Researchers address some aspects regarding the modeling of a hydraulic circuit of a commercial excavator.
2013-05-15
Technical Paper
2013-01-9016
Massimo Rundo, Raffaele Squarcini
Aim of this work is the development of a lumped parameters simulation model of single-vane vacuum pumps for pneumatically actuated brake boosters. Kinematic and fluid-dynamic models are integrated in a simulation environment to create a tool aimed at evaluating the vacuum pump performance and at guiding the designer during the prototype development. The paper describes extensively the mathematical model, the time domain simulation and experimental analyses performed on a camshaft mounted unit. Great emphasis is placed on the evaluation of the geometric quantities of the control volumes into which the vacuum pump has been divided. For each control volume the mass and energy conservation equations lead to the determination of the instantaneous pressure. The volume of each variable chamber and the respective angular derivative are calculated as function of the shaft position starting from the stator track profile supplied as a generic closed polyline. Flow areas between each chamber and the inlet/outlet volumes during a complete shaft revolution are evaluated directly from a data file containing the x-y coordinates of the passage area contour.
2013-04-08
Technical Paper
2013-01-0317
Roberto Finesso, Daniela Misul, Ezio Spessa
The present work has the aim of developing a semi-empirical correlation to estimate the NO₂/NOx ratio as a function of significant engine operating variables in a modern EURO VI diesel engine. The experimental data used in the present study were acquired at the dynamic test bench of ICEAL-PT (Internal Combustion Engine Advanced Laboratory at the Politecnico di Torino), in the frame of a research activity on the optimization of a General Motors Euro VI prototype 1.6-liter diesel engine equipped with a single-stage variable geometry turbine and a solenoid Common Rail system. The experimental tests were conducted over the whole engine map. A preliminary analysis was carried out to evaluate the uncertainty of the experimental acquired data and the NO₂/NOx ratio. The main engine variables which were expected to be related to the NO₂ formation were then identified, and a second-order polynomial model was introduced to model the NO₂/NOx ratio as a function of the abovementioned related engine variables.
2013-04-08
Technical Paper
2013-01-0964
Nicoletta Filippo, Massimiliana Carello, Massimo D'Auria, Alex Marcello
Given the growing concern for environmental issues, the automotive industry is working more deeply on the development of innovative technologies that reduce gas emissions and fuel consumption. Many car manufacturers have identified hybrid electric vehicles (HEV) and fuel cell vehicles as the most promising solutions alternatives. IDRApegasus is a fuel cell hydrogen vehicle developed at the Politecnico of Turin. It participated at the Shell Eco-marathon Europe in Rotterdam (Netherlands) from 17-19 May 2012, a competition for low energy consumption vehicles and also an educational project that joins the value of sustainable development with a vehicle that will use the smallest amount of fuel and produce the lowest emissions possible. The vehicle raced in prototype category with the objective to complete ten laps of a representative urban circuit in the normal driving direction, covering a total distance of 16.3 km in a maximum time of 39 minutes, with an average speed of approximately 25 km/h.
2013-04-08
Technical Paper
2013-01-0866
Mirko Baratta, Stefano D'Ambrosio, Daniela Anna Misul
An experimental investigation was performed on a turbocharged spark-ignition 4-cylinder production engine fuelled with natural gas and with two blends of natural gas and hydrogen (15% and 25% in volume of H₂). The engine was purposely designed to give optimal performance when running on CNG. The first part of the experimental campaign was carried out at MBT timing under stoichiometric conditions: load sweeps at constant engine speed and speed sweeps at constant load were performed. Afterwards, spark advance sweeps and relative air/fuel ratio sweeps were acquired at constant engine speed and load. The three fuels were compared in terms of performance (fuel conversion efficiency, brake specific fuel consumption, brake specific energy consumption and indicated mean effective pressure) and brake specific emissions (THC, NOx, CO). The pressure trace was acquired in the four cylinders to perform a cycle-by-cycle and cylinder-by-cylinder analysis of the peak firing pressure and the indicated mean effective pressure as well as of the main combustion parameters.
2013-04-08
Technical Paper
2013-01-1162
Mauro Velardocchia, Michiel Unger, Alessandro Vigliani, Nicola Leone, Kajetan Kietlinski, Enrico Galvagno
The paper presents a simulation methodology created to support an integrated safety system development process which was tested for the side impact collision load case. The methodology is based on the coupled and complementary use of two software packages: PreScan and Madymo. PreScan was utilized for designing two traffic scenarios and the sensing and control systems for the side collision recognition, while Madymo was utilized for assessing the effects of pre-crash deployment of thorax airbag. The collision conditions from the scenarios were used as input to define a Madymo side collision model of the host vehicle and to investigate and optimize several airbag deployment parameters: pre-crash deployment time, airbag permeability, vent hole size and vent hole opening time. Results showed that the best system configuration to reduce occupant injuries is achieved when the airbag is deployed in the pre-crash phase to push away the driver from the intrusion zone in the first phase of the crash.
2013-04-08
Technical Paper
2013-01-1679
Federico Millo, Fabio Mallamo, Theodoros Vlachos, Claudio Ciaravino, Lucio Postrioti, Giacomo Buitoni
The effects of using blended renewable diesel fuel (30% vol.), obtained from Rapeseed Methyl Ester (RME) and Hydrotreated Vegetable Oil (HVO), in a Euro 5 small displacement passenger car diesel engine have been evaluated in this paper. The hydraulic behavior of the common rail injection system was verified in terms of injected volume and injection rate with both RME and HVO blends fuelling in comparison with commercial diesel. Further, the spray obtained with RME B30 was analyzed and compared with diesel in terms of global shape and penetration, to investigate the potential differences in the air-fuel mixing process. Then, the impact of a biofuel blend usage on engine performance at full load was first analyzed, adopting the same reference calibration for all the tested fuels. Afterwards, the effects of a biofuel blend usage on brake specific fuel consumption and on exhaust emissions were also evaluated at 7 different part load operating conditions, representative of the New European Driving Cycle.
2013-04-08
Technical Paper
2013-01-0455
Ligia Munteanu, Dan Dumitriu, Veturia Chiroiu, Pier Paolo Delsanto
In mathematical and mechanical modeling terms, automotive seating is characterized by boundary conditions at the nonlinear contact interfaces. These contact interfaces are subjected to vibro-impacts (slaps) and frictional slips. The slaps occur in contact interfaces at high amplitude vibrations, being characterized by very short duration, rapid dissipation of energy and large accelerations and decelerations. By considering friction in contact interface modeling, the simulation of the interaction between the driver and the vehicle seat becomes more realistic. Vibro-impacts and frictional slips can be simultaneously developed in a contact surface. The boundary conditions identification for a seat and a wide range of drivers' body types is performed using the concept of interference distance or penetration. The interference distance is introduced as an optimization problem. It is shown that the optimization problem provides robust solutions to minimum distance and interference problems.
2013-04-08
Technical Paper
2013-01-1115
Federico Millo, Giacomo Di Lorenzo, Emanuele Servetto, Andrea Capra, Massimo Pettiti
The aim of this work is the assessment of the predictive capabilities of fast running models, obtained through an appropriate reduction and simplification process from detailed 1D fluid-dynamic models, for a turbocharged s.i. engine under highly transient operating conditions. Simulations results have been compared with experimental data for different types of models, ranging from fully detailed 1D fluid-dynamic models to map-based models, quantifying the degradation of the model accuracy and the reduction in the computational time for different kinds of driving cycles, from moderately transient such as the NEDC to highly dynamic such as the US06. Although the map based approach was confirmed to be be a viable means to predict fuel economy over the NEDC cycle, even for a downsized and turbocharged engine, thanks to the low accelerations involved and to the almost negligible transients effects, it showed significant discrepancies (error higher than 5%) with the experimental data when applied to highly dynamic driving cycles such as the US06.
2012-09-24
Technical Paper
2012-01-2040
Gabriele Altare, Damiano Padovani, Nicola Nervegna
The paper addresses some aspects of an ongoing research on a commercial compact excavator. The interest is focused on the analysis and modelling of the whole hydraulic circuit that, beside a load sensing variable displacement pump, features a stack of nine proportional directional control valves modules of which seven are of the load sensing type. Loads being sensed are the boom swing, boom, stick and bucket, right and left track motors and work tools; instead, the blade and the turret swing users do not contribute to the load sensing signal. Of specific interest are the peculiarities that were observed in the stack. In fact, to develop an accurate AMESim modelling, the stack was dismantled and all modules analysed and represented in a CAD environment as 3D parts. The load sensing flow generation unit was replaced on the vehicle by another one whose analysis and modelling have been developed using available design and experimental data. Although both the Hydraulic Component Design library as well as the Planar Mechanical library were used extensively in the process of modelling the entire circuit, some simplifications became necessary and are detailed in the paper.
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