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Technical Paper

3D Large Scale Simulation of the High-Speed Liquid Jet Atomization

2007-04-16
2007-01-0244
In this paper three-dimensional Large Eddy Simulations (i.e., LES) by using a PLIC-VOF method have been adopted to investigate the atomization process of round liquid jets issuing from automotive multi-hole injector-like nozzles. LES method is used to compute directly the effect of the large flow structure, being the smallest one modelled. A mesh having a cell size of 4 μm was used in order to derive a statistics of the detached liquid structures, i.e. droplets and ligaments. The latter have been identified by using an algorithm coded by authors. Cavitation modeling has not been included in the present computations. Two different mean injection nozzle flow velocities of 50 m/s and 270 m/s, corresponding to two mean nozzle flow Reynolds numbers of 1600 and 8700, respectively, have been considered in the calculations as representative of laminar and turbulent nozzle flow conditions.
Technical Paper

A 3D User and Maintenance Manual for UAVs and Commercial Aircrafts Based on Augmented Reality

2015-09-15
2015-01-2473
Traditional User/Maintenance Manuals provide useful information when dealing with simple machines. However, when dealing with complex systems of systems and highly miniaturized technologies, like UAVs, or with machines with millions of parts, a commercial aircraft is a case in point, new technologies taking advantage of Augmented Reality can rapidly and effectively support the maintenance operations. This paper presents a User/Maintenance Manual based on Augmented Reality to help the operator in the detection of parts and in the sequence to be followed to assemble/disassemble systems and subsystems. The proposed system includes a handheld device and/or an head mounted display or special goggles, to be used by on-site operators, with software management providing data fusion and overlaying traditional 2D user/maintenance manual information with an augmented reality software and appropriate interface.
Technical Paper

A Numerical Methodology for the Multi-Objective Optimization of an Automotive DI Diesel Engine

2013-09-08
2013-24-0019
Nowadays, an automotive DI Diesel engine is demanded to provide an adequate power output together with limit-complying NOx and soot emissions so that the development of a specific combustion concept is the result of a trade-off between conflicting objectives. In other words, the development of a low-emission DI diesel combustion concept could be mathematically represented as a multi-objective optimization problem. In recent years, genetic algorithm and CFD simulations were successfully applied to this kind of problem. However, combining GA optimization with actual CFD-3D combustion simulations can be too onerous since a large number of simulations is usually required, resulting in a high computational cost and, thus, limiting the suitability of this method for industrial processes.
Journal Article

Acoustic Emission Processing for Turbocharged GDI Engine Control Applications

2015-04-14
2015-01-1622
In the field of passenger car engines, recent research advances have proven the effectiveness of downsized, turbocharged and direct injection concepts, applied to gasoline combustion systems, to reduce the overall fuel consumption while respecting particularly stringent exhaust emissions limits. Knock and turbocharger control are two of the most critical factors that influence the achievement of maximum efficiency and satisfactory drivability, for this new generation of engines. The sound emitted from an engine encloses many information related to its operating condition. In particular, the turbocharger whistle and the knock clink are unmistakable sounds. This paper presents the development of real-time control functions, based on direct measurement of the engine acoustic emission, captured by an innovative and low cost acoustic sensor, implemented on a platform suitable for on-board application.
Technical Paper

Airship and Hot Air Balloon Real Time Envelope Shape Prediction through a Cloth Simulation Technique

2015-09-15
2015-01-2578
The flight simulation of airships and hot air balloons usually considers the envelope geometry as a fixed shape, whose volume is eventually reduced by ballonets. However, the dynamic pressure or helium leaks in airships, and the release of air to allow descent in hot air balloons can significantly change the shape of the envelope leading to potential dangerous situations. In fact, in case of semi-rigid and non-rigid airships a reduction in envelope internal pressure can reduce the envelope bending stiffness leading to the loss of the typical axial-symmetric shape. For hot air balloons thing goes even worse since the lost of internal pressure can lead to the collapsing of the balloon shape to a sort of vertically stretched geometry (similar to a torch) which is not able to sustain the attached basket and its payload.
Technical Paper

An Integrated Software Environment for UAV Missions Support

2013-09-17
2013-01-2189
This paper describes the design and development of a virtual environment conceived to support flight operations of an Unmanned Air Vehicle (UAV) used for wind mapping in the proximity of existing or planned wind farms. The virtual environment can be used in pre-flight briefings aiming to define a trajectory from a list of waypoints, to change and eventually re-plan the mission in case of intersection with no fly zones, to simulate the mission, and to preview images/videos taken from the UAV on-board cameras. During flight, the tool can be used to compute the wind speed along the trajectory by analyzing the data streaming from the UAV. The integration of Augmented Reality (AR) techniques in the flight environment provides assistance in remotely piloted landings, and allows visualizing flight and environmental information that are critical to the mission.
Technical Paper

Combined Optimization of Energy and Battery Thermal Management Control for a Plug-in HEV

2019-10-07
2019-24-0249
This paper presents an optimization algorithm, based on discrete dynamic programming, that aims to find the optimal control inputs both for energy and thermal management control strategies of a Plug-in Hybrid Electric Vehicle, in order to minimize the energy consumption over a given driving mission. The chosen vehicle has a complex P1-P4 architecture, with two electrical machines on the front axle and an additional one directly coupled with the engine, on the rear axle. In the first section, the algorithm structure is presented, including the cost-function definition, the disturbances, the state variables and the control variables chosen for the optimal control problem formulation. The second section reports the simplified quasi-static analytical model of the powertrain, which has been used for backward optimization. For this purpose, only the vehicle longitudinal dynamics have been considered.
Technical Paper

DGI - Direct Gasoline Injection Status of Development for Spark-Ignited Engines

2002-11-19
2002-01-3519
The first part of the paper gives an overview of the results obtained with European GDI-powered vehicles launched on the market. Thereafter, a discussion of in-vehicle limitations due to the exhaust gas after-treatment system requirements is given. The paper continues with a description of the current development status of European lean stratified direct injection system layouts. A detailed presentation is made of the mixture preparation system key components, basic control algorithms and the necessary new high-level experimental and analytical development tools. Particularly the topic of the multi-purpose use of 3-D numerical simulation is addressed both in the development and the engine control strategy calibration phases. The development of a small 1.6 liter lean stratified engine project is taken as example to demonstrate the dual application capability of the 3D simulation tool.
Journal Article

Design of Catalytic Devices by Means of Genetic Algorithm: Comparison Between Open-Cell Foam and Honeycomb Type Substrates

2016-04-05
2016-01-0965
Metallic foams or sponges are materials with a cell structure suitable for many industrial applications, such as reformers, heat catalytic converters, etc. The success of these materials is due to the combination of various characteristics such as mechanical strength, low density, high specific surface, good thermal exchange properties, low flow resistance and sound absorption. Different materials and manufacturing processes produce different type of structure and properties for various applications. In this work a genetic algorithm has been developed and applied to support the design of catalytic devices. In particular, two substrates were considered, namely the traditional honeycomb and an alternative open-cell foam type. CFD simulations of pressure losses and literature based correlations for the heat and mass transfer were used to support the genetic algorithm in finding the best compromise between flow resistance and pollutant abatement.
Technical Paper

Design, Optimization, Performances and Flight Operation of an All Composite Unmanned Aerial Vehicle

2013-09-17
2013-01-2192
Unmanned Aerial Vehicles (UAVs) provide the ability to perform a variety of experimental tests of systems and unproven research technologies, including new autopilot systems and obstacle avoidance capabilities, without risking the lives of human pilots. This paper describes the activities of design, optimization, and flight operations of a UAV conceived at Clarkson University (USA) and equipped to perform wind speed measurements to support wind farmsite planning. The UAV design has been assisted and validated by the use of an automatic virtual environment for the assisted design of civil UAVs. This tool can be used as a “computing machine” for civil UAVs. The operator inputs the mission profile and other generic parameters and data about performance, aerodynamics, and weight breakdown are extracted. A mathematical model of the UAV for flight simulation and its dynamic computations, along with automatic drawing is also produced.
Technical Paper

Development and Validation of a Control-Oriented Analytic Engine Simulator

2019-09-09
2019-24-0002
Due to the recent anti-pollution policies, the performance increase in Spark Ignition (SI) engines is currently under the focus of automotive manufacturers. This trend drives control systems designers to investigate accurate solutions and build more sophisticated algorithms to increase the efficiency of this kind of engines. The development of a control strategy is composed of several phases and steps, and the first part of such process is typically spent in defining and investigating the logic of the strategy. During this phase it is often useful to have a light engine simulator, which allows to have robust synthetic combustion data with a low calibration and computational effort. In the first part of this paper, a description of the control-oriented ANalytical Engine SIMulator (ANESIM) is carried out.
Technical Paper

Exhaust noise design based on psycho-acoustic parameters

2000-06-12
2000-05-0312
People make judgements of the sound produced by vehicles in a variety of situations and contexts. The most common type of assessment is an overall judgement of sound quality like pleasantness and sportiveness. From the car manufacturer''s point of view it is important to note that subjective judgements of sound influence the buyer''s opinion of the performance and value of the vehicle. Consequently, there is a need to quantify the subjective perception of the sound quality associated with a vehicle. This paper presents a study of the sound quality of vehicle exhaust noise based on the correlation between the subjective perception associated with this type of sound and measured psycho-acoustic parameters such as loudness, sharpness and roughness. The tailpipe noise of a selection of representative vehicles was recorded using an artificial head. A subjective evaluation of these sound recordings was made by a jury using standard relative techniques.
Technical Paper

Experimental Validation of a Model-Based Water Injection Combustion Control System for On-Board Application

2019-09-09
2019-24-0015
Water Injection (WI) has become a key technology for increasing combustion efficiency in modern GDI turbocharged engines. In fact, the addition of water mitigates significantly the occurrence of knock, reduces exhaust gas temperatures, and opens the possibility to reach optimum heat release phasing even at high load. This work presents the latest development of a model-based WI controller, and its experimental validation on a GDI TC engine. The controller is based on a novel approach that involves an analytic combustion model to define the spark advance (SA) required to reach a combustion phase target, considering injected water mass effects. The calibration and experimental validation of the proposed controller is shown in detail in the paper.
Journal Article

Individual Cylinder Air-Fuel Ratio Control for Engines with Unevenly Spaced Firing Order

2017-03-28
2017-01-0610
The most recent European regulations for two- and three-wheelers (Euro 5) are imposing an enhanced combustion control in motorcycle engines to respect tighter emission limits, and Air-Fuel Ratio (AFR) closed-loop control has become a key function of the engine management system also for this type of applications. In a multi-cylinder engine, typically only one oxygen sensor is installed on each bank, so that the mean AFR of two or more cylinders rather than the single cylinder one is actually controlled. The installation of one sensor per cylinder is normally avoided due to cost, layout and reliability issues. In the last years, several studies were presented to demonstrate the feasibility of an individual AFR controller based on a single sensor. These solutions are based on the mathematical modelling of the engine air path dynamics, or on the frequency analysis of the lambda probe signal.
Technical Paper

Rapid Prototyping as a Tool to Support Wind Tunnel Testing of Unconventional Unmanned Airships

2013-09-17
2013-01-2193
Scaled models are often used to check the aerodynamic performance of full scale aircraft and airship concepts, which have gone through a conceptual and preliminary design process. Results from these tests can be quite useful to improve the design of unconventional airships whose aerodynamics might be quite different from classical configurations. Once the airship geometry has been defined, testing is required to acquire aerodynamic data necessary to implement the mathematical model of the airship needed by the flight control system to develop full autonomous capabilities. Rapid prototyping has the great potential of playing a beneficial role in unconventional autonomous airship design similarly to the success obtained in the design process of conventional aircrafts.
Technical Paper

Setup of a 1D Model for Simulating Dynamic Behaviour of External Gear Pumps

2007-10-30
2007-01-4228
External gear pumps are widely used in many different applications because of their relatively low costs and high performances, especially in terms of volumetric and mechanical efficiency. The main weaknesses of external gear pumps can be summarized as follows: 1 Sudden increase or decrease of pressure inside volumes between teeth, which could lead respectively to noise emissions and to cavitation onset; 2 Necessity of limiting power losses and increasing volumetric efficiency, obtainable by reducing leakage flows between components; 3 Need of maintaining an ad-hoc minimum lubrication film thickness. In recent years many efforts, in terms of mathematical models and experimental tests, were done in order to limit energy losses and noise emissions. With the aim of deeply studying dynamic behaviour of external gear pumps and addressing their design, a 1D model was developed by means AMESim® code.
Technical Paper

Vehicle Dynamics Modeling for Real-Time Simulation

2013-09-08
2013-24-0144
This paper presents a 14 degrees of freedom vehicle model. Despite numerous software are nowadays commercially available, the model presented in this paper has been built starting from a blank sheet because the goal of the authors was to realize a model suitable for real-time simulation, compatible with the computational power of typical electronic control units, for on-board applications. In order to achieve this objective a complete vehicle dynamics simulation model has been developed in Matlab/Simulink environment: having a complete knowledge of the model's structure, it is possible to adapt its complexity to the computational power of the hardware used to run the simulation, a crucial feature to achieve real-time execution in actual ECUs.
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