Design methods for mobility

The paper tackles an integrated use of object-oriented modelling (OOM) and design of experiments (DoE) to determine the performance of a double bowden power window system in order to accomplish the expected system performances during the preliminary designing phase and, therefore, by accelerating the product development process. A DoE has been carried out by using the power window model, developed in Dymola environment. The response surface method (RSM) and ANOVA analysis are used to identify the significant factors. Then, an empirical equation is derived. It predicts the main system response i.e. the stroke time, expressed as dependency related to the significant factors. Finally, the use of the empirical relation inside a design flow of a power window, based on digital patterns, is presented.

Keywords: Design of experiments , Digital pattern for product development , Mechatronic systems , Object-oriented modeling , Power window systems

Every year approximately more than one million people die on world's road. Human factors are the largest contributing factors to the traffic crashes and fatality, and recent researches have identified drivers' cognitive aspect as the major cause of human errors in 80% of crash events. Thus, the development of countermeasures to manage drivers' cognitive aspect is an important challenge to address. Driver-Assistance Systems have been developed and integrated into vehicles to acquire data about the environment and the driver, and to communicate information to the driver, usually via the senses of vision and hearing. Unfortunately, these senses are already subjected to high demands, and the visual and auditory stimuli can be underestimate or considered as annoying. However, other sensory channels could be used to elicit the drivers' cognitive aspect. In particular, smell can impact on various aspects of humans' psychological state, such as people's attention level, and can induce activation states in people. The research presented in this paper aims at investigating whether olfactory stimuli, instead of auditory ones, can be used to influence the cognitive aspect of the drivers. For this purpose, an experimental framework has been set up and experimental testing sessions have been performed. The experimental framework is a multisensory environment consisting of an active stereo-projector and a screen used for displaying a video that reproduces a very monotonous car trip, a seating-buck for simulating the car environment, a wearable Olfactory Display, in-ear earphones and the BioGraph Infiniti system for acquiring the subjects' physiological data. The analysis of the data collected in the testing sessions shows that, in comparison to the relaxation state, olfactory stimuli are effective in increasing subjects' attention level more than the auditory ones.

This work analyzes a double wishbone type front suspension using a pushrod/rocker system to connect the chassis directly to the upright, linking the steering to the spring movement, and the related impact on racecar handling dynamics. The system has been used in the last 15 years in open wheel racing but yet no scientific analysis was done. Up to now its behaviour was analyzed using extensive testing. In this work this particular suspension design is analyzed using an analytical steady-state vehicle model, which includes previously calculated suspension derivatives and a full vehicle Multibody System (MBS) model to validate the theoretical approach. The final results are the suspension design guidelines.

In high altitude operations, the cooling system takes part to the vehicle design optimization process. An integrated design of the cooling ducts is strictly necessary. At high altitudes, the cooling air is taken from high-pressure areas into an alternate, extremely optimized, path. A diffuser reduces the airspeed and increases pressure of the cooling air. Then a group of high performance finned radiators rejects the heat from coolant, air charge and oil. The high altitude, after diffuser radiator performance is discussed in this paper. At first high performance Formula 1 radiators are introduced and discussed. Experimental data are also exposed and summarized. The pressure drop and heat rejection are expressed in function or Re and Pr numbers of cooling air. Then the radiator performance at high altitude is extrapolated from the ground test data. Finally a few suggestions on radiator and cooling ducts arrangement are introduced.

Keywords: Cooling , HALE , Meredith effect , Optimization , Radiators , UAV

Low BSFC (Brake Specific Fuel Consumption) and flat-altitude-rating make piston engines ideal choice for subsonic flight at altitudes up to 20, 000m-65, 000ft. These propulsion systems are more complex than traditional applications that are normally limited to 5, 000-7, 000m (16, 000-23, 000ft). In fact, the air propulsion (propeller or fan), the air intake and the cooling system take part have huge volumes. Therefore, their design influences vehicle aerodynamics as a whole. The cooling system is an integral part of aircraft design. As assessed from WWII design heritage, the cooling duct can be a static subsonic ramjet: the Meredith cooling duct. At high altitudes, the Meredith duct air is taken from highpressure areas into an alternate, extremely optimized, path. This path should end with a nozzle in a low pressure, high turbulence area of the aerial vehicle. In subsonic ramjet cooling ducts, the "static compressor" or diffuser is the most critical part. In fact the maximum compression ratio is below 1.5. Its efficiency highly influences the total thrust and the cooling efficacy of the duct. The Meredith duct should be embedded in the fuselage or in the wing to avoid excessive external drag. Only the air intake is positioned outside. In propeller systems, the intake is positioned in the lower part of the aircraft at about 2/3 of the wing chord, where the pressure reaches its maximum. In propeller systems, the high altitude engine intake can be positioned at the end of diffuser to increase the engine boost. In this way the turbomachinery mass and volume is reduced and the power to mass ratio of the propulsion system is increased. In fan systems, higher pressure is present inside the fan duct. In this paper, the preliminary design of the cooling duct is introduced. However, a CFD/wind tunnel optimization is strictly necessary to achieve a fully effective system. In any case, the requirements of low weight, high reliability and long endurance HALE (High Altitude Long Endurance) UAVs (Unmanned Aerial Vehicle) requires further work on this specific subject.

Keywords: Cooling , Diffuser , HALE , Meredith effect , Optimization , UAV

Low BSFC (Brake Specific Fuel Consumption) and flat-altitude-rating make piston engines ideal choice for altitudes up to 20,000m-65,000ft. These propulsion systems are more complex than traditional applications that are normally limited to 5,000-7,000m (16,000-23,000ft). In fact, the air propulsion (propeller or fan), the air intake, the fuel system, the turbocharging, the exhaust and the cooling system take part to the design optimization process. An integrated design is strictly necessary. At high altitudes, the intake air is taken from high-pressure areas into an alternate, extremely optimized, path. In propeller systems, a diffuser is usually positioned in the lower part of the aircraft. It converts kinetic energy into pressure. In fan systems, a little amount of "high pressure" air is taken from the high-pressure area of the fan. In lower power units, automotive-derived turbochargers can achieve the required pressure ratio. However, this option is limited by the maximum amount of volumetric flow rate. Moreover, automotive turbocharger housings have to be redesigned to use low-weight inconel alloys instead of heavier cast-iron. A complete redesign of the high pressure turbocharger (the unit closer to the engine manifold) can achieve pressure ratios from 8:1 to 10:1. This expensive process increases the power to mass ratio of the propulsion system. For higher power rating over about 200 kW axial compressorturbine assemblies derived from small turboshafts can be used as a turbocharging unit. In this case the burner is substituted by the piston engine. Especially for diesel engines, the advantage lies in the efficiency (BSFC). In fact, the maximum temperature reached in the diesel combustion chamber is about 4200K and the air flow is much lower than traditional turboshafts. Hybrid and turbocompound solutions are also possible. The exhaust and the intake of the piston engine have to be redesigned. However, the requirements of low weight, high reliability and long endurance HALE (High Altitude Long Endurance) UAVs (Unmanned Aerial Vehicle) requires further work on this specific subject.

Keywords: HALE , Optimization , Propulsion , Serial cascade arrangement , Turbochargers , UAV

Diesel and spark-ignition piston engines are an ideal choice for long endurance, high altitude operations (10, 000m/33, 000ft) and extremely high altitude operations (20,000m-65,000ft). These systems are more complex than traditional applications that are normally limited to 5, 000-7, 000m (16, 000-23, 000ft). In fact, the air propulsion system (propeller or fan), the air intake, the fuel system, the turbo charging, the exhaust and the cooling system take part to the design optimization process. An integrated design is strictly necessary. Since prop-fan is currently under development, the design should start from the choice between propeller and fan. This choice will influence optimum cruise speed, critical altitude and aircraft design as a whole. The air induction system is extremely important to improve efficiency, endurance and critical altitude. At low altitude, a filtered induction system is used for takeoff. At high altitudes, the intake air is taken from high-pressure areas into an alternate, extremely optimized, path. This induction system recovers as much pressure as possible, air kinetic energy at cruise speed. In propeller systems, the intake is usually positioned in the lower part of the aircraft. On fan systems, a little amount of "high pressure" air is taken from the high-pressure area of the fan. The exhaust system is also critical with the choice between pressure recovery and thrust. Exhaust-pressure-recovery reduces backpressure and temperature at exhaust. However, the improvement in critical altitude is marginal. In more common, thrust driven exhaust systems, the exhaust energy is converted into speed and thrust. At the relatively high speed of high altitude cruise, also the cooling system adds a small amount of thrust through the Meredith's effect. The piston engine power plant design is then extremely critical. Many different components should find the correct position for maximum performance. The power-plants of WWII water-cooled fighters and bombers are good examples, even if their design cruise altitude is below 10, 000m (33, 000ft). Modern turbofan and turbojet air intakes are also of help. However, the requirements of low weight, high reliability and long endurance HALE (High Altitude Long Endurance) UAVs (Unmanned Aerial Vehicle) requires further work on this specific subject.

Keywords: Cooling , HALE , Meredith effect , Optimization , Thruster , UAV

This paper demonstrates that the experience from Formula 1 and watercraft racing can be applied directly to assess and improve the aircraft/maritime conversion of automotive commercial engines. A direct comparison of the main parameters that characterizes modern CRDID (Common Rail Direct Injection Diesel) and Formula 1 racing engine demonstrates that the similarities are hidden inside the design criteria. In fact, CRDIDs should output high torque at low rpm (1000-3000rpm) while racing engine should have top torque at 9000-11000 rpm. This fact introduces much shorter strokes in racing engines that reduce inertia loads. Since pressures are higher for CRDIDs the combustion loads are similar. The techniques used to improve the TBO of Formula 1 spark ignition engine and racing watercraft diesel can then be directly applied to naval and aircraft engines where the low-cost requirements are not so stringent as in mass-produced automotive CRDIDs (millions of items). The same technology that prolongs the Formula 1 TBO from a single race to the whole season can then be successfully used in aircraft/naval CRDIDs. A quantitative assessment of the TBO increase is included in this paper for the various systems that compose a CRDID.

Keywords: Common rail , Friction , Load factor method , Piston engines , TBO , Wear

This paper demonstrates that efficiency and torque output of the actual Formula 1 power units depends mostly on the turbocharger (TC) efficiency. Compressor and turbine off-design efficiency and turbine energy recovery capability should be maximized to maximize the torque to fuel ratio. Since larger TCs increase turbolag, a new layout for the intercooler is proposed in this paper. This solution reduces turbolag and make it possible to focus on the TC efficiency as a thermal machine. In fact, not only the TC design choices can radically alter the efficiency of the TC itself, but also influence the efficiency of the ICE and of the MGU (Motor Generator Units). Energy evaluation of the TC readily exploits the concept.

Keywords: Compressor , ERS , Formula 1 , Intercooler , Turbine , Turbocharger

A feasibility study for the installation of a CRDID (Common Rail Direct Injection Diesel) on a light helicopter is introduced. The total mass available for the CRDID is evaluated starting from fuel consumption and helicopter data. The conversion of an automotive unit was discarded to excessive mass and excessive costs of the conversion. A derivative of an automotive engine was then considered. This solution proved to be feasible. The installation of the new CRDID was then studied. The turbocharger and the cooling system were defined for the application. The result was the evaluation of the power plant installation mass that proved to be much lower than the maximum admissible. The installation is then possible.

Keywords: Common rail , Diesel , Helicopter

This paper presents the implementation of a new boarding strategy that exploits passenger and hand-luggage detection and classification to reduce the boarding time onto an airplane. A vision system has the main purpose of providing passengers data, in terms of agility coefficient and hand-luggage size to a seat assignment algorithm. The software is able to dynamically generate the passenger seat that reduces the overall boarding time while taking into account the current airplane boarding state. The motivation behind this work is to speed up of the passenger boarding using the proposed online procedure of seat assignment based on passenger and luggage classification. This method results in an enhancement of the boarding phase, in terms of both time and passenger experience. The main goal of this work is to demonstrate the usability of the proposed system in real conditions proving its performances in terms of reliability. Using a simple hardware and software setup, we performed several experiments recreating a gate entrance mock up and comparing the measurements with ground truth data to assess the reliability of the system.

Keywords: Agility measurement , Boarding strategy , Computer vision

The minimization of the turnaround time, the duration which an aircraft must remain parked at the gate, is an important goal of airlines to increase their profitability. This work introduces a procedure to minimize of the turnaround time by speeding up the boarding time in passenger aircrafts. This is realized by allocating the seat numbers adaptively to passengers when they pass the boarding gate and not before. Using optical sensors, an agility measure is assigned to each person and also a measure to characterize the size of her/his hand-luggage. Based on these two values per passenger and taking into account additional constraints, like reserved seats and the belonging to a group, a novel seat allocation algorithm is introduced to minimize the boarding time. Extensive simulations show that a mean reduction of the boarding time with approximately 15% is achieved compared to existing boarding strategies. The costs of introducing the proposed procedure are negligible, while the savings of reducing the turnaround time are enormous, considering that the costs generated by inactive planes on an airport are estimated to be about 30 $ per minute.

Keywords: Agility coefficient , Boarding , Cost saving , Seat allocation algorithm , State feedback , Turnaround time

SPR joints will represent an alternative solution to spot welding in automotive field. However, their fatigue behavior shows several critical issues. After a brief introduction of this new solution, different crack modes are described, emphasizing the parameters that characterize them, i.e. the applied loads, the geometry of the joint and other phenomenon as fretting, vibration and corrosion.

Keywords: crack , fatigue load , joint , SPR

This paper aims to realize an eco-comparison among power-train configurations of hybrid busses in terms of performance, fuel consumption and CO2 emission. The present study has been carried out in the context of the international research program PLACIS (PLAteforme Collaborative d'Ingénierie Systèmes). In this work, experimental data of a pure electric power-train, evaluated in a dedicated laboratory of Istituto Motori-the National Research Council of Italy, have been used to carry out a pre-design phase of the modelling procedure. From that point on, in order to optimize the powertrain performance, a series hybrid vehicles configuration and a parallel one have been modeled and simulated on DYMOLA-MODELICA environment. The vehicle that has been taken into account, as reference for the comparison, is a «RENAULT-Master» minibus. Power-trains have been modeled with a backward-forward configuration in order to have a physical approach to the problem, respecting the required performances. The study has been developed with System Engineering approach that aims to manage the complexity of systems with a multidisciplinary proposal.

Keywords: Backward-forward configuration , CO emission 2 , Dymola , Eco-comparison , Electrical power-train , Hybrid Electric Vehicles , Modelica , PLACIS , System Engineering

The enhancement of the early design stages, in the production of aeronautical engines, has been shown decisive, for developing efficient and reliable final products. Nevertheless, in most of industrial engineering design problems, the amount of design variables is large. Moreover, several nonlinearities characterize the behaviour of the physical phenomena involved and the derivatives are seldom known for all the functions. Besides, objective functions exhibit several local extremes, whereas the designer as well as the practitioner is usually interested in the global one. In this context, stochastic and evolutionary optimization have been shown capable to provide reliable solutions while keeping the computational cost at a reasonable level. Existing tools for the design and optimization of engine components deal with the optimal and detailed design of specific engine components, thus requiring several computational time and efforts to gain optimized design parameters. Hence, existing tools fit for later design phases. Conversely, this paper proposes an integrated design and optimization environment, for automatically designing optimal aeronautical piston engine configuration, still in the conceptual design stage. The optimization is performed using the MATLAB genetic algorithm (GA) toolbox®, while the automatic design of the optimized components is carried out in cascade to the optimization phase. In particular, a single-objective GA is used to evaluate the optimal dimensions of engine components related to motion, namely: crankshaft, connecting rods and screws, flywheel, propeller shaft and torsional vibration damper. For testing the efficiency of the integrated environment, the conceptual design of components of a 4-in-line Diesel aeronautical piston engine is proposed, starting from an existing similar engine. Results show a reduction of the 20 % of weight of the crankshaft in comparison to the original configuration. The proposed environment seems to be a promising tool for a fast and reliable conceptual design of piston engines for aeronautical purposes.

Keywords: Automatic design , CAD models , Conceptual design optimization , Genetic algorithm , Stochastic optimization

Urban air pollution causes deleterious effects on human health and the environment. To meet stringent standards imposed by the European Commission, advanced measurement methods are required. Remote sensing techniques, such as light detection and ranging (LiDAR), can be a valuable option for evaluating particulate matter (PM), emitted by vehicles in urban traffic, with high sensitivity and in shorter time intervals. Since air quality problems persist not only in large urban areas, a measuring campaign was specifically performed in a suburban area of Crotone, Italy, using both a compact LiDAR system and conventional instruments for real-time vehicle emissions monitoring along a congested road. First results reported in this paper show a strong dependence between variations of LiDAR backscattering signals and traffic-related air pollution levels. Moreover, time-resolved LiDAR data averaged in limited regions, directly above conventional monitoring stations at the border of an intersection, were found to be linearly correlated to the PM concentration levels with a correlation coefficient between 0.75 and 0.84.

Keywords: air pollution , light detection and ranging , particulate matter , remote sensing , Urban , vehicle emissions

The paper deals with automotive power window systems and, in particular, tackles the problem of validating the object-oriented model of a single bowden system, to be used within a Model-Based System Engineering (MBSE) approach. Therefore, the paper tackles the problem of increasing accuracy of object-oriented models by defining model refinements i.e. by identifying objects whose modelling has to be improved. Firstly, the role of object-oriented modelling and the main characteristics of the power window system are summarized. Then, the object-oriented model of an automotive single bowden power window system is presented. Finally, the experimental phase, performed to characterize the behavior of the real system is summarised and the validation of simulation model, as well as the identification of model refinement, are accomplished.

Keywords: mechatronic systems , model validation , object-oriented modeling , single bowden power window system

This paper deals with an application of Discrete Event Simulation (DES) within the manufacturing process of a high-speed train. Today, the use of a DES tool is common for supporting engineers in designing the production lines and planning the production, representing a valid help in what-if analyses and in the measurement or validation of a solution. In this research activity, differently from the common use, it has been developed a DES model whose function is not to measure and/or validate a solution of a problem, but to generate a solution that will be nearly to the optimum. This paper describes DES tools, the methodology used in this work, the model built, the case-study and the obtained results.

Keywords: Discrete event simulation , Production planning , Scheduling optimization , Virtual manufacturing

This paper deals with the development of a Knowledge Based Engineering (KBE) methodology for supporting a manufacturing company, in particular railway manufacturers, in their analyses for reusing existing products in new projects. The proposed methodology is based on the development of a Decision Support System (DSS) and the use of an analysis, called Adopt/Adapt/Innovate (AAI), aimed at identifying products already designed that fully or partly fit what required by new bids. The DSS is built within a PLM software and part of the research concentrated on comparing the PLM suites available in the market searching for the best tool able to act the role of a centralized management dashboard for knowledge reuse. DSS and AAI analysis are the base for future research activities for obtaining a KBE system that automatically models complex railway products starting from the customer requirements, drastically reducing the time to market.

The paper deals with a digital pattern (DP) approach to the design of an automotive power window, using object-oriented modelling. Therefore, the paper faces the designing of a mechatronic system by using an integrated approach to product development. Then, Dymola/Modelica environment is used as a tool of a decision support system that makes possible the DP approach. The paper briefly sum up the results of simulations related to a power window system characterized by a double bowden sliding mechanism. Finally, the paper highlights the parameters that could be easily integrated in a graphical user interface, aimed to reduce both the development time of new power window system and to increase the accuracy of design activities.

Keywords: Digital pattern for product development , Mechatronic systems , Objectoriented modeling , Power window systems