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In this study, the role of turbulence-chemistry interaction in diesel spray auto-ignition, flame stabilization and end of injection phenomena is investigated under engine relevant “Spray A” conditions. A recently developed diesel spray combustion modeling approach, Conditional Source-term Estimation (CSE-FGM), is coupled with Reynolds-averaged Navier-Stokes simulation (RANS) framework to study the details of spray combustion. The detailed chemistry mechanism is included through the Flamelet Generated Manifold (FGM) method. Both unsteady and steady flamelet solutions are included in the manifold to account for the auto-ignition process and the subsequent flame propagation in a diesel spray. Conditionally averaged chemical source terms are closed by the conditional scalars obtained in the CSE routine. Both non-reacting and reacting spray jets are computed over a wide range of Engine Combustion Network (ECN) diesel. “Spray A” conditions. The reacting spray results are compared with simulations using a homogeneous reactor combustion model and a flamelet combustion model with the same chemical mechanism. The present study represents the first application of CSE for a diesel spray. The non-reacting liquid/vapour penetration, the mean and RMS mixture fraction, the reactive region, the flame lift-off and the ignition delay show a good agreement with literature data from an optically accessible combustion vessel over a wide range of tested conditions. The CSE-FGM model also shows a better capability in predicting the end-of-injection events in diesel spray combustion. Overall, the CSE-FGM model is shown to capture the experimental trends well, both quantitatively and qualitatively.

International audience; The Phylog project aims at offering a model-based software-aided certification framework for aeronautical systems based on multi/many-core architectures. Certifying such platforms will entail fulfilling the high level objectives of the MCP-CRI / CAST-32A position paper. Among those, two types of analysis are required: interference and safety analyses. Because of the large size of the platforms and their complexity, those analyses can lead to combinatorial explosion and to some misinterpretation. To tackle these issues, we explore a service-based modelling approach that leads to a simplification of the analyses and to the highlighting of salient properties, making the adaptation of the certification argumentation efficient.

This paper presents a high-fidelity electro-thermal model of a half-bridge that consists of IGBTs and anti-parallel diodes. The model calculates and estimates the half-bridge voltages, currents, switching and conduction losses considering the operating temperature and current conditions. Moreover, this model is suitable for varying switching frequency operation. The electro-thermal model can be used as an evaluation tool to analyze the performance of control strategies for traction inverter from efficiency, temperature and component stress point of view. In this paper performance of Direct Torque Model Predictive Control (DTMPC) of an Interior Permanent Magnet Synchronous Motor (IPMSM) is evaluated in comparison with Indirect Field Oriented Control (IFOC) with sinusoidal pulse width modulation (PWM). The inverter model and the MPC are both implemented in C-Mex for rapid execution. The MPC algorithm implemented in this research tracks torque reference while using Maximum-Torque-Per-Ampere (MTPA) strategy and minimizing switching losses. Both control systems are able to follow the speed reference. The MPC shows a decrease in losses compared to IFOC when tested with low-speed and high-speed parts of the WLTC profile.

International audience; Global warming has put the transport sector, a major contributor of CO 2 emissions, under high pressure to improve efficiency. In this context, ultra-light vehicles weighting less than 500 kg, as well as hybrid powertrains, are nowadays seen as promising development trends. The design process of the powertrain of a vehicle combining the advantages of the two concepts is presented in this paper. Through a performance study based on a simple MATLAB model, and mathematical simulation, a proposal is made. A powertrain using a battery and supercapacitor 48V dual power source network, two electric motors and clutches to switch between conventional, parallel, series and full electric modes proves to be an interesting system in terms of performance and costs. A simulation study conducted on a scenario with different outcome possibilities showed that high modularity of the system allows to achieve fuel efficiencies equivalent to approximately 3 l/100 km on the Artemis cycle. Finally, integration, packaging and cost are considered and some hints for further powertrain efficiency improvements are presented.

International audience; This paper describes the contribution of the closed-loop control of the motion platform (six degrees of freedom: longitudinal, lateral, and vertical displacements; pitch, roll, yaw) and motion platform’s three-dimensional (3D) displacement scale factor (SF) (0.2 and 1.0) on eye pupil diameter (PD) as an objective measure of driver cognitive load. Longitudinal, lateral, and vertical accelerations as well as longitudinal, lateral, and vertical positions from the center of gravity (CG) of the vehicle were registered through the driving simulation software SCANeRstudio® from OKTAL. Closed-loop control decreases the driver mental load. This type of closed-loop control can be used to decrease the driver mental load.

It has been predicted that the prevailing COVID-19 situation would result in increased demand for personal vehicles. There is a renewed interest in the 3 wheeled vehicles for short urban mobility in western countries due to their inherent cost advantages which will make it affordable for the common man. As the world is moving towards electric vehicle technology, a light 3 wheeled vehicle option will also help in reducing battery weight and thereby help in addressing the range concerns. In addition, slow speed 3-wheelers need not pass extensive safety regulation tests in many western countries including the USA. Three-wheeled vehicles are not new to developing countries like India as three-wheeled auto-rickshaws are quite popular for short distance shared travel. The existing single front wheel design known as delta design may have a stigma attached to it due to historic reasons in India. There is also a perception that the three-wheeled vehicles are highly unstable. Therefore, the current paper studies in detail an alternate design known as the tadpole design having two wheels in the front. The tadpole configuration facilitates decent styling and good aerodynamics. The tadpole configuration is modeled and analyzed using CAE multibody dynamics software, MSC Adams Car. To get confidence in the simulation results, a few benchmarked and tested vehicles are selected from the available literature [1] and the MBD results are compared for correlation. The studies also include a standard four-wheeled vehicle and a delta configuration 3-wheeler for reference purpose. The MBD virtual analyses provide results for vehicle stability and handling characteristics like overturning speed limit, oversteer and understeer behavior during constant radius cornering tests. The paper, by keeping in mind the typical urban driving condition and pattern, gives its feedback and recommendation about the tadpole configured 3-wheeler. © 2021 SAE International. All rights reserved.

The paper deals with the reduction of pollutant emissions in urban areas by considering a Zero-Emission Zone (ZEZ) in which hybrid electric vehicles (HEVs) are allowed to be driven without using the internal combustion engine, as several cities have planned to realize in the next decades. Moreover, since vehicle connectivity has spread more and more in the last years, a vehicle-to-network (V2N) communication system has been taken into account to retrieve real-time navigation data from a map service provider and thus reconstructing the so-called electronic horizon, which is a reconstruction of the future conditions of the vehicle on the road ahead. The speed profile and the road slope are used as input for an on-board predictive control strategy of a plug-in HEV (PHEV). In particular, a dedicated algorithm predicts the amount of necessary energy to complete the city event in full-electric mode, giving a state of charge (SoC) target value. With this aim, an adaptive equivalent consumption minimization strategy (A-ECMS) has been modified to use navigation data for approaching the ZEZ with the target SoC. The paper finally quantifies the benefits of such an approach in terms of CO2 emissions by comparing it with a heuristic, rule-based one, which represents the standard OEM solution.

Research in any field of study requires analysis and comparisons or real-time predictions to extract useful information. To prove that the results have practical potential, various filtering techniques and methodologies should be designed and implemented. Filters being a class of signal processing helps innovate new technologies with various kinds of outcomes, using filters there are always various methods to solve a problem. Considering the current COVID-19 situation, researchers are working on sequencing the novel coronavirus and the genomes of people afflicted with COVID-19 using CPUs and GPUs along with various filtering techniques. In this paper we are using a method of filter implementation to collect raw heart rate data samples from fingertip and ear lobe and process those results on CPUs and GPUs. Our method of implementation to collect raw heart rate data is using a photoplethysmography method. We all know that the moving average filtering technique is the most commonly usedfor averaging an array of sampled data but in this paper we reconstructed the entire moving average filter with a slightly different averaging method where we will prove how our filter technique is better than the traditional moving average filter. This filtering technique is implemented and compared on both GPUs and CPUs. However, the filters on GPUs are slightly altered as per the GPU framework and CUDA programming techniques to optimize and output challenging results. We will also conduct Human trials for this concept and talk about how the heart rate changes while driving and also considering environmental conditions and scenarios. The findings of this work are also compared with apple watch heart rate data as it is the most accurate heart rate sensing device in the market with less than 2% error rate. © 2021 SAE International. All rights reserved.

Battery electric vehicles (BEV) share the ability of regenerative braking since they are equipped with two independent types of deceleration devices, namely the electric motor working as a generator and the friction brakes. Correct interaction of these systems in terms of driving safety and energy efficiency is a function of the Brake Blending Control. Individual electric motors for each wheel and a decoupled brake system provides the Brake Blending with a high design flexibility that allows significant advantages regarding energy consumption, brake performance, and driving comfort. This paper is focusing on the fail behaviour and analyses the robustness and redundancy abilities of such systems against various error scenarios. For this purposes, a distributed x-in-the-loop environment, consisting of dedicated simulation and hardware testing components, is introduced. The investigation is carried out based on a high-fidelity real-time simulation model of an electric sport utility vehicle with four in-wheel motors (IWM) and decoupled electro-hydraulic brake system. This model can be used for a detailed analysis of vehicle dynamics in case of brake system fails. The electro-hydraulic decoupled brake system is implemented through a Hardware-in-the-loop test rig, which allows a realistic fault injection. The vehicle stability and controllability is investigated under the circumstances of various brake system failures in the regenerative and friction brake system, respectively. These studies are presented according to standardized test scenarios like Straight line braking (DIN 70028) and Brake-in-turn (ISO 7975). With obtained x-in-the-loop simulation results, the impact of a failure on vehicle dynamics is discussed in the final part of the paper.

Object trackers are a tool to achieve accurate object state estimation over time. Due to their complexity, a framework to experiment with different variations of trackers and their subcomponents is desired. This drove the authors research and experimentation with object tracking using MathWorks toolsets. In this paper, three object trackers - Point Target Tracker (PTT), Gamma Gaussian Inverse Wishart Probability Hypothesis Density (GGIW-PHD), and Gaussian Mixture Probability Hypothesis Density (GM-PHD) - are compared in simulation for track statistics and object/track accuracy. The results show that a rectangular GM-PHD multi object tracker outperforms the other trackers. A follow up is shown using real-world data and the process used to get the sensor data into the appropriate MathWorks format. The impact of COVID-19 prevented the collection of ground truth data so the real-world data cannot be compared using the same metrics. For this reason, the simulation portion of this paper will act as the detailed discussion of fusion and tracking while the real-world testing portion is an overview of the authors' process of converting real-world sensor data into a format compatible with MathWorks object tracking tools. © 2021 SAE International. All rights reserved.

In today's era of rapid globalization and high consumer demand the automotive industry faces a major challenge to meet the growing demands for customized products, which suits the branding strategy, customer needs and industry trends. Modular approach to product development not only helps in reducing the product development time, but it also supports the automotive industry to customize the needs of consumers in an effective manner, create unique brand identity and reduce development cost. Product platform modularization is a great opportunity for the original equipment manufacturers (OEM's) to develop platform strategies across multiple brands and the ability to customize products. During current pandemic times with COVID-19, automotive manufactures will need to rethink their product strategies and focus on the platform mindset to deliver products that meet consumer demands. The paper provides a novel approach in developing modular platform solutions by defining guidelines for "Common"and "Unique"modules linked with critical interfaces. It also provides ways to keep "Brand"uniqueness by maintaining modularity with the systems. A theoretical process is described in the paper with few examples to illustrate the modular approach and branding strategy. The paper also provides a basic approach for all vehicle types to allow manufacturers to focus their efforts on areas where there is high degree of modularity and commonality using the branding strategy. © 2021 SAE International. All Rights Reserved.

This paper was commissioned for the design and analysis of an entire rear suspension system befitting a Formula Society of Automotive Engineers (FSAE) vehicle. The paper includes a literature review to gain a full understanding of the workings and design decisions applied to the rear suspension in the Society of Automotive Engineers (SAE) competition. After completing the design development process, a final analysis of the designed system was done to ensure the minimum two years-of-life requirement is met. It was found that due to constraints, a major design change was necessary that involves mounting the A-arms further forward on the chassis body than previous generation vehicles. This design increased the stresses present in the system compared to previous designs. As such, careful consid-eration had been given to the analysis aspect of the paper. Full fatigue analysis performed individually on each component proved that the lower A-arm was the most critical component, with a predicted failure at 1466 laps. However, with the given lifespan of two years, this design procured a conservative Factor of Safety of above two years.Notable mention should be given to the complete develop-ment of an FSAE uniaxial force determination code that was produced by Team Recoil. This code greatly improved the confidence in component forces and thus allowed less conservative design choices in several other aspects.

This paper conceptualizes the design of a single-seater All-Terrain Vehicle (ATV). The aim was to design and fabricate a lightweight, high strength vehicle (under 175kgs) which can withstand harsh terrains, while being affordable and easily manufacturable. This paper covers the extent of design and simulations ranging from static structural, fatigue analysis, explicit dynamics etc. have been carried out. Tools such as SolidWorks, Ansys and MATLAB have been used throughout the process.The report is divided into individual subsystems, such as Chassis, Braking, Powertrain, Suspension and Steering. All the design considerations and objectives of each of the subsystems have been included. Simulation results of various components such as the Chassis, A-arms, Knuckles, Hubs and integral mounts have been attached with focus on modelling based on real-time forces and behaviors.

This paper describes a multi-degree-of-freedom model of a three-wheeled car, implemented in Matlab®. The purpose was to investigate the dynamics of the car (assumed to be rigid on its suspension) during cornering. While the problems associated with three-wheeled cars are well-known, much of the guidance in the literature and off-the-software assumes a conventional four-wheeled car. Consequently, the authors were approached with a battery-electric concept car which was thought to offer better performance than existing variants, because the use of hub motors lowered the centre of gravity and hence reduced rollover coefficient. However, simulation of the vehicle model in cornering shows that the concept is still prone to instability. Indeed, it suffers greater roll velocities than a comparable three-wheeled car with internal combustion engine, because the ratio of sprung to unsprung mass is significantly altered. This paper therefore recommends a programme of further simulations and model-based design changes to progress the concept to a marketable performance product.

The automotive trends of vehicles with lower aerodynamic drag and more powerful drivetrains have caused increasing concern regarding stability issues at high speeds, since more streamlined bodies show greater sensitivity to crosswinds. This is especially pronounced for high vehicles, such as sports utility vehicles. Besides, the competitiveness in the automotive industry requires faster development times and, thus, a need to evaluate the high speed stability performance in an early design phase, preferable using simulation tools. The usefulness of these simulation tools partly relies on realistic boundary conditions for the wind and quantitative measures for assessing stability without the subjective evaluation of experienced drivers. This study employs an on-road experimental measurements setup to define relevant wind conditions and to find an objective methodology to evaluate high speed stability. The paper focuses on the events in proximity to the drivers’ subjective triggers of instability. Wind direction and magnitude, vehicle motion response, along with the subjective event triggering were measured at different conditions of the natural wind. A statistical approach was utilized to analyze the correlation between the vehicle response and subjective triggers together with the wind conditions. A correlation was established between the subjective triggers and a rapid change in lateral acceleration and yaw velocity response. The paper also proposes a set of four crosswind gust profiles of interest for driving stability, combining results from previous research and the experimental data of the natural wind obtained in this study. These findings can be used as objective measures for virtually assessing stability performance and as realistic boundary conditions for simulating wind gusts.

Connected vehicles (CVs) have situational awareness that can be exploited for control and optimization of the powertrain system. While extensive studies have been carried out for energy efficiency improvement of CVs via eco-driving and planning, the implication of such technologies on the thermal responses of CVs has not been fully investigated. One of the key challenges in leveraging connectivity for optimization-based thermal management of CVs is the relatively slow thermal dynamics, which necessitate the use of a long prediction horizon to achieve the best performance. Long-term prediction of the CV speed, unlike the V2V/V2I-based short-range prediction, is difficult and error-prone. The multiple timescales inherent to power and thermal systems call for a variable timescale optimization framework with access to short- and long-term vehicle speed preview. To this end, a model predictive controller (MPC) with a multi-range speed preview for integrated power and thermal management (iPTM) of connected hybrid electric vehicles (HEVs) is presented in this paper. The MPC is formulated to manage the power-split between the engine and the battery while enforcing the power and thermal (engine coolant and catalytic converter temperatures) constraints. The MPC exploits prediction and optimization over a shorter receding horizon and longer shrinking horizon. Over the longer shrinking horizon, the vehicle speed estimation is based on the data collected from the connected vehicles traveling on the same route as the ego-vehicle. Simulation results of applying the MPC over real-world urban driving cycles in Ann Arbor, MI are presented to demonstrate the effectiveness and fuel-saving potentials of the proposed iPTM strategy under the uncertainty associated with long-term predictions of the CV's speed., 15 pages, 15 figures, 1 table, to appear in 2020 WCX SAE World Congress Experience, SAE Technical Paper 2020-01-0590

Powered two-wheeler (PTW) riders and passengers are among the group of vulnerable road users (VRU). This group uses the road transportation system together with other better-protected users such as passenger cars and truck drivers. The main vulnerability of PTW rider lies in their unequal position during the crash, due to the inability of application of the crashworthiness concept during the PTW vehicle design. This inequality could be somehow mitigated by the design of personal protective equipment (PPE). Mostly the design of the PPE’s is led by the standards which often are obsolete and takes into account only simple drop-tests (ECE 22.05). Those tests did not take into account complicated kinematics of the motorcycle accidents and biomechanics of the human body (the assessment is based only on the linear acceleration of the headform center of gravity). The authors propose a virtual approach for the PTW rider injury risk assessment, which coupled with the pre-impact conditions, could be used for the new PPE protection standards preparation. In this paper, authors want to present a numerical study on the most common PTW impact scenarios, which are described in ISO 13232. The simulations of the accidents were conducted in the VPS numerical environment (PAM-Crash explicit solver). Accidents participants, namely opposite vehicle (OV) modeled by finite element method (FEM) approach, powered two-wheeler (PTW) modeled by multibody system (MBS) approach, PTW driver represented by hybrid FE-MBS human body model Virthuman and a helmet (modeled by FE approach) were coupled to represent the 7 most common accident scenarios. The helmet is the only PPE enforced by the law, but not in all territories (Afghanistan, Dominica, Guyana, Mexico, Libya, Senegal, USA). Due to the complexity of the OV FE model, there was a necessity of model simplification and revalidation, which also was done in this work. The results of the simulations were examined with special emphasis on realistic representation of real accident kinematics. In each configuration, an injury risk assessment was done on the PTW rider model. The assessment was done based on injury criterion used by the NCAP, UNE 135900 and the LNL criterion. The paper shows that the virtual approach using the Virthuman human body model could be used for the simulation of PTW accidents. The results of this paper could be used for future PPE design.

Development processes for modern combustion engines already make substantial use of more or less sophisticated simulation approaches. The enhancement of computational resources additionally allows the increasing use of simulation tools in terms of time-consuming three-dimensional CFD approaches. In particular, the preliminary estimation of feasible operating ranges and strategies requires a vast multitude of single simulations. Here, multi-zone simulation approaches incorporate the advantages of comparably short simulation durations. Nevertheless, the combination with more detailed sub-models allows these rather simple modeling approaches to offer considerable insight into relevant engine operation phenomena. In the context of combustion process development, this paper describes a phenomenological model approach for the prediction of operating point characteristics of a dual-fuel pilot injection combustion process. In order to describe the ignition initiated by pilot fuel injection, the present model approach uses the package-based multi-zone approach as presented by Hiroyasu et al. Therefore, physical phenomena such as spray breakup, atomization, and evaporation are considered. The governing entrainment of premixed cylinder charge into the individual package zones is based on the conservation of momentum. In addition, measured pilot fuel injection profiles are implemented. The calculation of the characteristic ignition delay time applies an Arrhenius-based one-step mechanism taking local gas properties as well as the particular composition within the packages into account. Eventually, the identification of the ignition event triggers a transition process from the combustion within the spray cone to the hemispherical flame propagation of the premixed cylinder filling. Besides the detailed description of the model approach, this paper discusses crucial influences originating from quasi-dimensional discretization. In particular, the radial discretization of the spray jet indicates a considerable influence on the prediction of spray breakup as well as fresh gas mixing into the package zones and thus eventually on the calculation of the ignition delay time. The validation of the phenomenological model approach regarding its ability to predict different operating characteristics uses experimental data. Here, variations of timing and the quantity of the pilot fuel injection as well as variations of injection pressure and global air-fuel equivalence ratio have been taken into account. The model approach indicates plausible prediction with regard to both the basic phenomenology of the combustion process and the characteristic two-stage ignition behavior. In particular, cylinder pressure curves and combustion rates as well as peak pressures and the overall released heat quantities are correctly calculated.

Losses reduction and oil flow optimization management in construction machines and, in general, in heavy duty vehicles are two of the most challenging missions of today fluid power research. One of the most promising ideas is to implement multiple hydraulic power sources but this requires a flexible pump switch system; in fact, depending on flow request and machine mode, one or more pumps can be switched to serve each actuator. To put into practice these concepts it is necessary to in-depth design the distribution system, through which hydrostatic transmissions supply the different loads. The new component here presented realizes the pump switch management, creating a matrix framework of the hydraulic flow connections. Putting this concept it into practice the new architecture is able to connect alternatively a pump to one actuator at a time providing also for cross connections, enabling different sources flow summation. The matrix for oil flow management is aimed at offering a flexible, safe and scalable solution, and it can be replicated to form a stack, providing a physical matrix of rows and columns for oil distribution to actuators. The basic rule for the matrix management is that only a single actuator can be fed by each pump, but more connections can be activated for an actuator, offering a flexible flow management and enabling a new approach to pump sizing studies on machines. The component is a rotating distributor with a safety spool, that can connect discharge and return ports of one pump to the A and B port of each actuator, moving the safety spool only when the rotary distributor is coupled with the desired actuator. Both closed center and open center configurations are possible, as well as regenerative systems can be implemented. The paper will focus mainly on design concept and architectural alternatives and potential benefits of the implementation of the concept on state of art architectures from the functional capability point of view.

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. The third section describes the Model-in-the-Loop environment of the vehicle, implemented in Simulink. In particular, the validation of the fuel consumption and the battery temperature models against experimental data is shown, and the original control strategies for the energy and thermal management are described, as well. This powertrain model is used to evaluate vehicle performance. As the powertrain architecture offers different torque split possibilities, different approaches to the powertrain control are considered, starting from the baseline rule-based controllers for both the thermal and energy management, to the combined-optimization based controllers. This paper shows a consistent fuel economy improvement due to energy management optimization, which becomes even larger if thermal management is included in the optimization algorithm.

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. The latest results about the zero-dimensional knock model presented in a previous paper and some interesting analytical equations which define the main mean-combustion indexes trends (for example maximum in-cylinder pressure, or Pmax, 50 percent fuel mass fraction burned angle, or MFB50, Indicated Mean Effective Pressure, or IMEP) as functions of engine speed and load are analyzed for the entire engine operating range. A detailed sensitivity analysis to the fitting order is presented and the final formulas are showed and used for the calibration. The second part focuses on the model implementation in a Simulink environment and the resulting validation process of the analytic simulator carried out on a Gasoline Direct Injection (GDI) Turbo Charged (TC) engine. ANESIM performance is then tested by comparing the calculated and the experimental data, for both steady state and transient operating conditions.

A major challenge in automotive NVH engineering is to approach complex structure-borne sound and vibration problems with sufficient accuracy but reasonable experimental effort. Typical issues encountered are poor correlation between objective component performance criteria tested for during bench validation and corresponding subjective targets evaluated during system validation in the actual vehicle. Additional challenges arise from the need to impose assumptions on sophisticated physical vibration problems to reduce the complexity to a level feasible for conventional experimental test methods. This paper addresses all mentioned issues by elaborating on a system NVH engineering approach employing Virtual Acoustic Prototyping (VAP) (related to what is now often called component Transfer Path Analysis) to synthesize time domain sound and vibration responses of vibrating machinery operated in a virtual vehicle environment. One crucial step of VAP is to characterize the strength of vibrating machinery by independent quantities at the significant coupling degrees of freedom (DoF). This study puts special focus on the measurement of free velocity, suitable for machinery operated when resiliently mounted as per ISO 9611, and the in-situ measurement of blocked forces, applicable for sources connected to any type of receiving structure during operation, as per ISO/DIS 20270. In order to reduce complexity of the underlying measurements this paper investigates the possibility of using collocated sensor arrays and methods to validate assumptions imposed to abstract away from rotational coupling DoF. An electric power steering (EPS) system inducing vibrations into a sub-frame-type structure is considered as a representative automotive source-receiver installation to investigate the feasibility of free velocity and in-situ blocked force approach with respect to independent source characterization for component Transfer Path Analysis (TPA) and VAP. The obtained Virtual Acoustic Prototype is expanded using an algorithm to synthesize realistic time domain data, enabling NVH engineers to conduct reliable objective and subjective design evaluations.

This paper presents a methodology used to configure an electric drive system for a Formula Student car and the detailed design of a transmission for in-hub motor placement. Various options for the size, number and placement of electric motors were considered and a systematic process was undertaken to determine the optimum configuration and type of motor required. The final configuration selected had four 38 kW in-hub motors connected through a 14.8:1 reduction transmission to 10” wheels. Preliminary design of the transmission design indicated that the overall gear ratio would be best achieved with a two-stage reduction, and in this work an offset primary spur stage coupled to a planetary second stage was chosen. Detailed design and validation of the transmission was conducted in Ricardo SABR and GEAR, using a duty cycle derived from an existing internal combustion Formula Student car. The analysis was conducted in line with ISO 6336 and permitted the examination of the stresses in gear teeth and the prediction of gear and bearing life. A detailed design was proposed with due regard to ease of manufacture and assembly, and a full-scale prototype was manufactured to facilitate physical validation of the design. The design analysis showed all gears and bearings had a suitable predicted lifetime with a minimum factor of safety of 1.8 on gear wear.

© 2019 SAE International. All Rights Reserved. Electric vehicles are considered as one of the most popular way to decrease the consumption of petroleum resources and reduce environmental pollutions. Motor control system is one of the most important part of electric vehicles. It includes power supply module, IGBT driver, digital signal processing (DSP) controller, protection adjustment module, and resolver to digital convertor. To implement the control strategies on motor control system, a lot of practical aspects need to be taken into accounts. It includes setup of the initial excitation current, consistency of current between motor and program code, over-modulation, field weakening control, current protection, and so on. In this paper, an induction motor control system for electric vehicles is developed based on DSP. The control strategy is based on the field-oriented control (FOC) and space vector pulse width modulation (SVPWM). Speed calculation, over-modulation, field weakening control, PI controller, and fault diagnosis are also applied in this DSP algorithm. As an industry product running on a real electric bus with a 100kW induction motor, communication with vehicle control unit (VCU) by CAN bus, control system safety and PC software designed for lab experiments are also discussed. This paper focused on how to develop the advanced motor control system for electric vehicles for industrial application. The steady-state and transient performances of this motor control system are analyzed by both test-bench experiments and road experiments. Its performance is satisfactory when applied to the real electric vehicle.

This paper presents a model based control strategy aimed to reduce noise and wear during gearshifts in conventional and hybrid Dual Clutch Transmissions (DCT and DCTH) and Automated Manual Transmissions (AMT). The control strategy is based on a newly developed dog teeth position sensor layout at China Euro Vehicle Technology AB (CEVT), a detailed simulation model for gear engagement and already existing speed sensors in the transmission. The details of dog teeth position sensor and simulation model are also presented in this paper. During gear shifting, noise is generated because of impacts between the sleeve teeth and the idler gear dog teeth after speed synchronization. Besides noise, these impacts are also responsible for delaying the completion of shift and contribute to wear in the dog teeth, hence reducing the lifespan of the transmission. The simulation model for gear engagement can simulate these impacts. Based on the simulation model and optimal control theory, an ideal dog teeth position trajectory is formulated that avoids the impact between sleeve and idler gear dog teeth, before the start of torque ramp up. The open loop strategy then controls the synchronization torque in the beginning of speed synchronization in such a way that the dog teeth position during shift follows the ideal dog teeth position trajectory. Since the control strategy is based on optimal control theory, its effect on speed synchronization time is minimal. The control strategy is designed in such a way that it can easily be applied in the existing transmission control software. By applying the control strategy on the simulation model, it is shown that the impacts during gear engagement are reduced.

© 2019 SAE International. All Rights Reserved. Evolvable Assembly Systems is a five year UK research council funded project into flexible and reconfigurable manufacturing systems. The principal goal of the research programme has been to define and validate the vision and support architecture, theoretical models, methods and algorithms for Evolvable Assembly Systems as a new platform for open, adaptable, context-aware and cost effective production. The project is now coming to a close; the concepts developed during the project have been implemented on a variety of demonstrators across a number of manufacturing domains including automotive and aerospace assembly. This paper will show the progression of demonstrators and applications as they increase in complexity, specifically focussing on the Future Automated Aerospace Assembly Phase 1 technology demonstrator (FA3D). The FA3D Phase 1 demonstrated automated assembly of aerospace products using precision robotic processes in conjunction with low-cost reconfigurable fixturing supported by large volume metrology. This was underpinned by novel agent-based control for transformable batch-size-of-one production. The paper will conclude by introducing Phase 2 of the Future Automated Aerospace Assembly Demonstrator - currently in development - that will translate the Evolvable Assembly Systems research to a higher technology readiness level and address the challenges of scalable and transformable manufacturing systems.

The paper deals with experimental testing of a natural gas fueled engine. Break Specific fuel Consumption (BSFC), Average Mass Flow Rate, Instantaneous Cylinder Pressure and some wall temperatures have been measured at some full and part load operating conditions. The results of this experimental activity, still in progress, have been used to calibrate a 1D-flow engine’s model. Then the effects of some VVA strategies have been theoretically studied through the validated model. With the aim of maximizing the full load engine’s torque, a genetic algorithm was used to calculate the optimized intake and exhaust valves timing angles. Various VVA strategies were compared at part-load in order to reduce brake specific fuel consumption.

Within the context of distributed power generation, small size systems driven by spark ignition engines represent a valid and user-friendly choice, that ensures good fuel flexibility. One issue is that such applications are run at part load for extensive periods, thus lowering fuel economy. Employing an inverter (fitted between the generator and load) allows engine operation within a wide range of crankshaft rotational velocity, therefore improving efficiency. For the purpose of evaluating the benefits of this technology within a co-generation framework, two configurations were modeled by using the GT-Power simulation software. After model calibration based on measurements on a small size engine for two-wheel applications, the downsized version was compared to a larger power unit operated at constant engine speed for a scenario that featured up to 10 kW rated power. Indeed, the downsizing concept was found to ensure an electrical efficiency improvement of around 10% at 50% load, over 30% at 20% load, and reduced fuel consumption by over 50% at lower load. The co-generation potential was also evaluated, and it resulted practically the same from full to 50% load, while at low load the larger engine featured heat recovery potential up to two times larger compared to the smaller unit.

In recent years, the More-Electric Aircraft (MEA) concept has undergone significant development and refinement, striving towards the attainment of reductions in noise and CO2 emissions, increased power transmission efficiency and improved reliability under a range of flight scenarios. The More-Electric Engine (MEE) is increasingly being seen as a key complementary system to the MEA. With this concept, conventional engine auxiliary systems (i.e. fuel pumps, oil pumps, actuators) will be replaced by electrically-driven equivalents, providing even greater scope for the combined aircraft and engine electrical power system optimisation and management. This concept, coupled with extraction of electrical power from multiple engine spools also has the potential to deliver significant fuel burn savings. To date, single or dual channel electrical power generation and distribution systems have been used in engines and aircrafts. However, with the increasing electrification of flight-critical engine auxiliaries along with the requirement for greater load transfer flexibility, a three-channel architecture should be considered. This paper investigates potential concepts for a three-channel power system architecture in an MEE system. The paper considers issues such as architecture layout and key technologies that may be considered for MEE architecture. Using an extensive database of public domain MEA/MEE power system component failure rates, a detailed fault tree analysis is then presented. This provides a quantitative comparison of dual channel and three-channel architecture candidates under the pertinent failure modes as well as showing the impact of common architecture features on system reliability and robustness. Finally, the paper concludes with a discussion of the ring busbar topology operation and power electronics technology requirements that could successfully implement a flexible and robust three-channel architecture for MEE systems.

Look ahead information can be used to improve the powertrain’s fuel consumption while efficiently controlling exhaust emissions. A passenger car propelled by a Euro 6d capable diesel engine is studied. In the conventional approach, the diesel powertrain subsystem control is rule based. It uses no information of future load requests but is operated with the objective of low engine out exhaust emission species until the Exhaust After-Treatment System (EATS) light off has occurred, even if fuel economy is compromised greatly. Upon EATS light off, the engine is operated more fuel efficiently since the EATS system is able to treat emissions effectively. This paper presents a supervisory control structure with the intended purpose to operate the complete powertrain using a minimum of fuel while improving the robustness of exhaust emissions. A supervisory controller assisted by look ahead information, and using a supervisory control interface that works in concert with low level local controllers, can make subsystems operate near optimal. The look ahead parametrized supervisory control calculates the set-points for the subsystems: Internal Combustion Engine (ICE), Lean NOx Trap (LNT) and the Selective Catalytic Reduction (SCR) based on the Emission Equivalent Fuel Consumption minimization strategy (EEFC). The controller performance is analyzed for the World wide harmonized Light vehicles Test Cycle (WLTC) and randomly sequenced WLTCs under different initial conditions. This paper extends upon the earlier work where an LNT-SCR EATS supervisory control structure was proposed that optimizes based on the EEFC strategy. The future work will focus on extending the approach to more subsystems and characterizing the look ahead information.

Due to stricter emission regulations and more environmental awareness, the powertrain systems are moving toward higher fuel efficiency and lower emissions. In response to these pressing needs, new technologies have been designed and implemented by manufacturers. As a result of increasing complexity of the powertrain systems, their control and optimization become more and more challenging. Virtual powertrain calibration, also known as model-based calibration, has been introduced to transfer a part of test bench testing into a virtual environment, and hence considerably reduce time and cost of product development process while increasing the product quality. Nevertheless, virtual calibration has not yet reached its full potential in industrial applications. Volvo Penta has recently developed a virtual test cell named VIRTEC, which is used in an ongoing pilot project to meet the Stage V emission standards. The integrated powertrain system includes engine, Exhaust Aftertreatment System (EATS), and Engine Management System (EMS). The objective of this paper is to describe the essential aspects required to increase the contribution of virtual testing in powertrain calibration activities. These aspects comprise the following: Hardware-in-the-Loop (HiL) system, simulation models, and working process for joint virtual and physical testing to facilitate efficient powertrain development process. The current paper describes the design, test and verification of a calibration platform based on the requirements of the project. The future phases in the current project (Virtual Calibration at Volvo Penta) will cover validation of the platform by performing calibrations in industrial scales on the virtual system.

This paper proposes a method for multi- objective parameter optimization of piecewise linear time profiles for control of Automatic Transmission (AT) shifts and presents results obtained on an example of a powertrain with a 10-speed automatic transmission. The paper first outlines the powertrain dynamics model. Then, the AT control trajectory optimization approach is outlined and employed with the aim of getting insights into the optimal shift control profiles and related performance. The parameter optimization problem is to find parameters of piecewise linear shift control profiles, which provide a trade-off between the shift comfort and performance. The optimization problem is solved by using the multi-objective genetic algorithm MOGA-II incorporated within modeFRONTIER environment. As an extension of the parameter optimization approach, a method for robust parameter optimization is proposed, which aims at ensuring high shift quality and robustness in the presence of transmission actuation parameter variations. The objective is to find shift control profile parameters that simultaneously minimize mean values of vehicle jerk and shift duration indices as well as their standard deviations for improved robustness against change of transmission parameters. The overall optimization approach is demonstrated first on an example of a single-transition power-on upshift, and the obtained optimization results are analyzed and compared to the control trajectory and non- robust parameter optimization results. The analysis points out that the shift robustness can be improved by sacrificing comfort. Finally, the method is applied to a double- transition power-on downshift to illustrate its applicability for more demanding transmission control tasks.

This paper shows the influence of different battery charge management strategies on the fuel economy of a hybrid parallel axle-split vehicle in a real driving scenario, for a vehicle control system that has the additional possibility to split the torque between front and rear axles. The first section regards the validation of a self-developed Model in the Loop (MiL) environment of a P1-P4 plug-in hybrid electric car, using experimental data of a New European Driving Cycle test. In its original version, which is implemented on-board the vehicle, the energy management supervisor implements a heuristic, or rule-based, Energy Management Strategy (EMS). During this project, a different EMS has been developed, consisting of a sub-optimal control scheme called Equivalent Consumption Minimization Strategy (ECMS), explained in detail in the second section. After that, the focus is on the evaluation of the benefits coming from different battery charge management strategies, which can be charge-sustaining, charge-depleting/charge-sustaining or charge blended, since the vehicle is a PHEV. The fuel economy improvements, using each strategy, are compared and one of them is then combined with the knowledge of future driving conditions (the so-called electronic horizon), mainly speed and altitude profiles. Therefore, the proposed controller would be ready for on-board implementation. In the last section, a sensitivity analysis that relates the results obtained with the battery capacity is carried out, to evaluate the influence of this strategic parameter on the battery charge management strategy choice. The paper shows the fuel economy potential of a physics-based approach like ECMS for a plug-in HEV, and how it can directly benefit from the prediction of future driving conditions, especially if the battery capacity is limited.

A path tracking control system is chosen as the proof-of-concept demonstration application in this paper. A disturbance observer (DOB) is embedded within the steering to path error automated driving loop to handle uncertain parameters such as vehicle mass, vehicle velocities and road friction coefficient and to reject yaw moment disturbances. The compensation of vehicle model with the embedded disturbance observer forces it to behave like its nominal model within the bandwidth of the disturbance observer. A parameter space approach based steering controller is then used to optimize performance. The proposed method demonstrates good disturbance rejection and achieves stability robustness. The variable time delay from the steer-by-wire system in an actual vehicle can also lead to stability issues since it adds large negative phase angle to the plant frequency response and tends to destabilize it. A communication disturbance observer (CDOB) based time delay compensation approach that does not require exact knowledge of this time delay is embedded into the steering actuation loop to handle this problem. Stability analysis of both DOB and CDOB compensation system are presented in this paper. Extensive model-in-the-loop simulations were performed to test the designed disturbance observer and CDOB systems and show reduced path following errors in the presence of uncertainty, disturbances and time delay. A validated model of our 2017 Ford Fusion Hybrid research autonomous vehicle is used in the simulation analyses. Simulation results verify the performance enhancement of the vehicle path following control with proposed DOB and CDOB structure. A HiL simulator that uses a validated CarSim model with sensors and traffic will be used later to verify the real time capability of our approach., arXiv admin note: text overlap with arXiv:2306.01899

One dimensional (1D) and three dimensional (3D) simulations are widely used in technical acoustics to predict the behavior of duct system elements including fluid machines. In particular, referring to internal combustion engines, the numerical approaches can be used to estimate the Transmission Loss (TL) of mufflers, air boxes, catalytic converters, etc. TL is a parameter commonly used in almost any kind of acoustical filters, in order to assess the passive effects related to their sound attenuation. In this paper, a previous 1D-3D acoustical analysis of a commercial muffler, has been improved and experimentally validated. Features related to the manufacturing process, like the coupling of adjacent surfaces and the actual shape of components, have been noticed to heavily affect the muffler behavior. Hence, although numerical analyses are usually performed on ideal geometries (perfectly matched and shaped), schematizations utilized for acoustic simulations of real mufflers are being suggested to do not neglect these important aspects. On the other hand, for a given initial muffler design, the manufacturing process is assessed to be a critical aspect also for its remarkable effects on the acoustics. In this work, results have been carried out under different muffler operating conditions related to different mean flow velocities and presence or not of internal insulating material. 1D analyses have been performed by implementing a commercial software, solving the nonlinear flow equations which characterize the wave propagation phenomena. 1D approach has also been utilized to evaluate the fluid dynamic behavior of the studied muffler in terms of pressure drop when a mean flow is imposed. 3D results are obtained in absence of mean flow by using a commercial software based on Boundary Element approach and solving the three dimensional Helmholtz's equation. Finally, during the experimental tests, the muffler has been treated as an acoustic two-port element.

The aim of the presented work is to estimate the vertical forces of heavy vehicle and identify the unknown dynamic parameters using sliding mode observers approach. This observation needs a good knowledge of some dynamic parameters such as damping coefficient, spring stiffness...etc. We propose in this paper, to identify some of these parameters which are, in practice very difficult to obtain and to measure. This identification will improve the quality of vertical forces estimation. Some experimental results are presented in order to show the quality of the estimation and identification. These estimation results are then compared to the measures coming from an instrumented tractor.

The paper summarizes the activities related to the characterization of the noise sources and related sound emission levels emitted by a single-cylinder diesel engine. A deep analysis is carried out aiming to clearly define the various noise sources, through the employment of numerical and experimental techniques. In particular, an intensimetric analysis is carried out to define a bi-dimensional noise level map around the engine. In addition, the gas-dynamic noise, at the different engine speeds, is measured through a microphone mounted near the intake and exhaust mouth. Contemporarily to the experimental activity, a theoretical one-dimensional simulation of the whole engine is also carried out. The presented one-dimensional analysis is able to characterize the wave propagation phenomena in the external ducts and provide the estimation of both engine performance and gas-dynamic noise emission too. The presented techniques allow to fully describe the noise emission behavior of the tested engine.

The major contribution of this paper is to propose a low-cost accurate distance estimation approach. It can potentially be used in driver modelling, accident avoidance and autonomous driving. Based on MATLAB and Python, sensory data from a Continental radar and a monocular dashcam were fused using a Kalman filter. Both sensors were mounted on a Volkswagen Sharan, performing repeated driving on a same route. The established system consists of three components, radar data processing, camera data processing and data fusion using Kalman filter. For radar data processing, raw radar measurements were directly collected from a data logger and analyzed using a Python program. Valid data were extracted and time stamped for further use. Meanwhile, a Nextbase monocular dashcam was used to record corresponding traffic scenarios. In order to measure headway distance from these videos, object depicting the leading vehicle was first located in each frame. Afterwards, the corresponding vanishing point was also detected and used to automatically compute the camera posture, which is to minimize the interference caused by camera vibration. The headway distance can hence be obtained by assuming the leading and host vehicles were in the same ground plane. After both sensory data were obtained, they were synthesized and fused using Kalman filter, to generate a better estimation of headway distance. The performances of both sensors were assessed individually and the correlation between their measurements was evaluated by replotting radar measurements on the video stream. The results of individual sensors and Kalman filter were compared to investigate the optimization performance of the data fusion approach.This is a general guidance of headway distance estimation with a low cost radar and a monocular camera. With described general procedures, this paper can allow researchers to easily fuse radar and camera measurements to obtain optimized headway distance estimation. This paper can facilitate the development of a more realistic robotic driver that can mimic human driver behaviors.

Knock control systems based on engine block vibrations analysis are widely adopted in passenger car engines, but such approach shows its main limits at high engine speeds, since knock intensity measurement becomes less reliable due to the increased background mechanical noise. For small two wheelers engines, knock has not been historically considered a crucial issue, mainly due to small-sized combustion chambers and mixture enrichment. Due to more stringent emission regulations and in search of reduced CO2 emissions, an effective on-board knock controller acquires today greater importance also for motorcycle applications, since it could protect the engine when different fuel types are used, and it could significantly reduce fuel consumption (by avoiding lambda enrichment and/or allowing higher compression ratios to be adopted). These types of engines typically work at high rotational speeds and the reduced signal to noise ratio makes knock onset difficult to identify. The paper shows how knock-related information can be extracted both from accelerometer and acoustic signals, and how the correlation with in-cylinder pressure based indexes can be optimized using advanced signal processing algorithms and specific calibration methodologies, for a wide engine speed range. An optimization procedure that has involved all the calibration parameters that make up sound and vibration-based knock indexes, has allowed to successfully apply knock detection techniques up to 13,000 rpm. Experimental results obtained on the engine test bench are shown throughout the paper, demonstrating the feasibility of both approaches, which provide similar signal-to-noise ratio levels, and can therefore be considered as possible alternatives.

Spark-ignited engines equipped by a three-way catalyst require a precise control of the air fuel ratio fed to the combustion chamber. A stoichiometric mixture is necessary for the proper working of the catalyst in order to meet the legislation requirement. A critical part of the air fuel ratio control is the feed-forward compensation of the fuel dynamics. Conventional strategies are based on a simplified model of the wall-wetting phenomena whose parameters are stored in off-line computed look-up tables. Unfortunately, errors in the parameters calibration over the whole engine map deteriorate the control performances in terms of emissions. In this paper an automatic procedure for a rapid and efficient identification of the wall-wetting parameters is presented. The whole procedure has been experimentally tested on a vehicle by using a test bench. Using the identified parameters values, a significant reduction in the air fuel ratio excursion has been achieved during rapid throttle transients with respect to the same vehicle equipped by a commercial ECU with resident engine maps computed by traditional calibration activity. Moreover, the algorithm can be also on-line used to improve air-fuel ratio control performances.

Internal combustion engines are the primary transportation mover for today society and they will likely continue to be for decades to come. Hybridization is the most common solution to reduce the petrol-fuels consumption and to respect the new raw emission limits. The gasoline engines designed for running together with an electric motor need to have a very high thermal efficiency because they must work at high loads, where engine thermal efficiency is close to the maximum one. Therefore, the technical solutions bringing to thermal efficiency enhancement were adopted on HVs (Hybrid Vehicles) prior to conventional vehicles. In these days, these solutions are going to be adopted on conventional vehicles too. The purpose of this work was to trace development guidelines useful for engine designers, based on the target power and focused on the maximization of the engine thermal efficiency, following the engine rightsizing concept. The originality of the present work stands in the comparison of the effectiveness of the most common strategies adopted today between two types of engine. The chosen engines for this study were modern boosted GDI engines, in line with the current automotive market, designed by CAD at the University of Bologna. 3D CFD computations of non-reacting flows were carried out by means Fire Code 2020 by AVL. The paper aimed to numerically investigate the rightsizing concept depending on the target level of power: two levels of power were chosen, 290 kW and 120 kW respectively, typical the former one of a high-power engine, the last one of an engine more devoted to efficiency purposes. The two engine bores were selected based on the common automotive solutions depending on the target power: 84 mm for the high-power engine, 75 mm for the other engine. Once fixed the bore value and pursuing the maximization of the thermal efficiency, a study on the possible geometries was performed, searching for the best stroke-to-bore ratio S/B: the long stroke engine design finds its limit in the maximum average piston speed, depending on the engine regime at maximum power. Then, the study was moved to the compression ratio increase and the adoption of over-expanded cycles, both aimed to increase the thermal efficiency. For solving the knocking issues arising from the adoption of increased compression ratio, the water injection strategy was analyzed too. Finally, some considerations were deduced on the effectiveness in applying the over-expanded cycles to the two different types of engine: the critical point to be solved is if the applicability and thus the effectiveness of the over-expanded cycles depend on the engine type.

The emergence of wide band gap devices has pushed the boundaries of power converter operations and high power density applications. It is desirable to operate a power inverter at high switching frequencies to reduce passive filter weight and at high temperature to reduce the cooling system requirement. The paper describes the design and test of a power electronic inverter that converts a fixed input DC voltage to a variable voltage variable frequency three phase output. The component selection and design were constrained such that the inverter can operate at an ambient temperature of 170°C. The design of the key functional components such as the gate drive, power module, controller and communication will be discussed in the paper. Test results for the inverter at high temperature will also be presented.

The current paper is based on the French research program TESSA (“Transfert des Efforts des Sources Solidiennes Actives”). A specific task within TESSA project consists in the characterization of the measurements variability between several laboratories, of the blocked forces on a water pump of a heat engine. This paper focuses only on the measurements carried out at Vibratec laboratory. Two kinds of measurements have been carried out: direct measurements, using force sensors, which is the target of the inter-laboratory measurements, and an inverse method without force sensor requirements. Reproducibility and repeatability tests have been done in order to quantify the measurement variability within the same laboratory, in preparation for the inter-laboratory disparity analysis. Specific supports have been designed for each method: a rigid aluminum block for the direct method and a support dedicated to the inverse method, including a high modal density and modal damping in the frequency range of interest. The comparison of both methods shows that the inverse method is satisfying for the measurement of blocked forces on a “non-rigid” support and that it is possible to apply such methodology “in-situ”, with the source in its real environment. Mots clefs : Source solidienne, Effort de blocage, Methode inverse 22 Congres Francais de Mecanique Lyon, 24 au 28 Aout 2015

Advanced numerical techniques, such as fuzzy logic and neural networks have been applied in this work to digital images acquired on a mono-component fuel spray (iso-octane), in order to define, in a stochastic way, the gas-liquid interface evolution. The image is a numerical matrix and so it is possible to characterize geometrical parameters and the time evolution of the jet by using deterministic, statistical stochastic and other several kinds of approach. The algorithm used works with the fuzzy logic concept to binarize the shades gray of the pixel, depending them, by using the schlieren technique, on the gas density. Starting from a primary fixed threshold, the applied technique, can select the ' gas' pixel from the 'liquid' pixel and so it is possible define the first most probably boundary lines of the spray. Acquiring continuously the images, fixing a frame and a sample rate, a most fine thresho ld can be select and, at the limit, the most probably geometrical parameters of the jet can be detected.

The trend toward the adoption of a multiprocessor system on a chip (MPSoC) in critical real-time domains, like avionics or automotive, responds to the demand for increased computing performance to support advanced software functionalities. The other side of the coin is that MPSoCs challenge software timing analysis. This is so as co-running applications affect each other’s timing behavior on account of the interference incurred when accessing shared hardware resources, with the latter steadily increasing in number and complexity in every new generation of MPSoCs. For a solid and cost-contained software-timing validation approach, we contend that a taxonomy has to be developed to capture the different levels at which processors’ resources can be shared. Those levels are to be related to the conventional run-time software abstractions (e.g., task, thread, runnable) and the particular abstraction used to carry out contention analysis. From the standpoint of contention analysis, only the resources in those levels shared by the different run-time software entities need to be mastered and addressed by timing analysis, whereas the remaining resources can be safely disregarded. We tailor this approach to two of NVIDIA’s embedded platforms, TX2 and AGX Xavier, of particular relevance for the automotive domain. For the identified shared resources, we also characterize the contention that tasks can suffer and discuss the limitations and early approaches for modeling timing interference in shared hardware resources. This work has been partially supported by the SpanishMinistry of Science and Innovation under grants PID2019-107255GB and FJCI-2017 -34095; and the European Union’s Horizon 2020 research and innovation programme under grant agreement No. 878752 (MASTECS) and the European Research Council (ERC) grant agreement No. 772773 (SuPerCom).

During aircraft development, mathematical models are elaborated from our knowledge of fundamental physical laws. Those models are used to gain knowledge in order to make the best decisions at all development stages. Depending on the application, different models can be used to describe, in one way or another, the aircraft behavior. The goal of this paper is to develop a high-fidelity aircraft simulation model that is exceptionally capable, flexible and responsive to the needs of the researchers. The proposed model includes nonlinear aerodynamic coefficients, a generic engine model and a complete autopilot with auto-landing. The simulation model has been designed to help researchers develop and validate new algorithms for trajectory optimization, control design, stability analysis and parameter estimation. To make it easy to use, the simulation model also includes algorithms for stability and control analysis. Methodologies based on Nelder-Mead’s optimization algorithm with a friendly user interface have been developed, allowing the trimming and linearizing of an aircraft’s model for any flight condition and any configuration. Similarly, the simulation model includes a flight control system (FCS) and a complete autopilot (AP), allowing aircraft to follow a specific trajectory. The FCS and the AP have been designed and tuned using a modified Genetic Algorithm and the Particle Swarm Optimization algorithm. A level D flight simulator of the Cessna Citation X was used to validate the proposed methodology. The results show that the simulation model presented in this paper is accurate and could be further used to analyze the business aircraft Cessna Citation X’s behavior. The simulation model could also be adapted for its use on other aircrafts.

Low Carbon fuels will play a relevant role in the transportation sector contributing, over the powertrain technology progress, to mitigate global CO2 emissions. Compressed Natural Gas (CNG), mainly composed by methane, is one of the best candidate thanks to its chemical composition and to its wide diffusion and use. Blending Hydrogen in Natural Gas could represent a further step for a better CO2 footprint (considering renewable or biohydrogen) but also to optimize the combustion process, increasing the engine thermal efficiency and reducing pollutant formation. On the other hand, capability to automatically adapt the engine parameters to variable concentrations of Hydrogen in Natural Gas (in the range from 0% to 40% by volume) is a mandatory step to maintain engine performance, emissions and efficiency The activities described in this paper are part of a large collaborative project, “Biomethair”, funded by Regione Piemonte, where material specifications on gas tanks, valves, feeding lines, gas pressure regulator, engine pipes and injectors have been set and prototype components procured and implemented into the demonstrator vehicle to ensure safe operating conditions. In this paper a software algorithm is presented, able to provide, during normal car operation, real time estimates of methane-hydrogen composition, allowing the engine control system to adapt the control parameters engine. The algorithm is based on the innovative data-driven technology Direct Virtual Sensor, which allows to design the Virtual Sensor from the experimental data collected from a testing car, subject to suitable manoeuvres in different operational conditions, without requiring deep first principle modelling of the involved systems. The Virtual Sensor has been designed and implemented on the Electronic Control Unit of the demonstrator vehicle, giving suitably discretized estimates of Methane-Hydrogen composition, using measurements of engine revolution speed, of the lambda probe value and a variable from engine control unit. Experimental results of the Virtual Sensor performance evaluated in different operational conditions are presented.