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Methodologies of a vehicle assessment through computer simulation comes to enable every day to preview difficulties in developing models, which also contributes to reducing the time to develop a new model. For initial assessment of the vibroacoustic behavior of a vehicle, in the early months of development, the frequency response functions, known as inertance (a/F), are analyzed, at the points of attachment of the engine and suspension to the body still in the Body-in-White configuration. Usually the finite element simulations are performed up to the limit of 300Hz. In the aim at increasing the range of inertance analysis, enabling a more comprehensive analysis in NVH, the results by elements finites simulation were compared, in this work, with the results obtained in experimental measurements focused on the validation of this simulation methodology until the limit of 800Hz.

This paper describes the development of an electrical compressor-driven air conditioning system for automotive applications. The system uses the thermal properties of reversible metal hydride alloys, which are retained within advanced-design hydride heat exchangers. Calculations on system performance predict high energy efficiency in a package of competitive size and cost. A proof-of-principle prototype has been constructed and bench tested. Measurements from initial tests confirm the excellent performance potential of this system. A study about on-board integration concludes that the system can be installed on a car and can provide all HVAC traditional functions.

The air conditioning system of a car uses the reverse Carnot thermodynamic cycle of a refrigerant gas. The fluids normally used have at least a direct impact on global warming, so their losses have to be avoided. A very simple method to detect refrigerant charge level was developed, using few standard sensors. Results show that it is possible to have an estimation of system charge level with satisfactory accuracy, and seems able to avoid complete loss of refrigerant.

The air conditioning system is becoming more and more a competitive issue, moving from optional to standard vehicle equipment. Therefore, also thermal comfort level is moving from simple air temperature measurement to a more systemic approach, where the contribution of every element of the car cabin has to be taken in account. Improving contact thermal sensation with the seat is one of the main issues to improve overall thermal comfort in transportation. A method has been defined to assess the perceived thermal quality of seats taking into account the sweating human thermoregulatory process. The method is based on a thermal manikin representing a torso able to simulate in a portion of the back the sweating phenomena. The first part of the paper is focused on the instrument and developed measuring method description. The second part is dedicated to detail the correlation between experimental measurements and subjective quality index obtained during an extensive on-road panel test.

The cabin comfort is one of the most competitive issues in the automotive area of business. The thermal comfort and the environmental well-being are fundamental performances that contribute to generate the more general idea of perceived quality. The CRF developed in the past the concept so-called “healthy bubble” that was implemented in the Lancia Dialogos concept car. The passengers are surrounded by an air bubble, created by generating low velocity air flows, that are diffused through the interior panels and components (e.g. dashboard, roof, back of the seats, etc.), and by surfaces temperature control (e.g. carpet, seats, etc.). At present the original idea has generally been accepted, and different solutions to diffuse air and to control surface temperature of vehicle interiors have been proposed by some automotive supplier.

A new category of hypereutectic aluminum liners, made by PM route is now available on the market (SILITEC) and it is successfully applied to high-pressure die casting process to produce open deck cylinder blocks. The claimed achievable engine performances over cast-iron liners (weight saving, reduction of oil consumption, optimal heat transfer, wear and friction losses reduction) justify the interest of automotive industry in developing such a technology. The paper will present the experience and the achieved results in permanent mold gravity casting with Silitec liners, where metal flow definition and temperature distribution control make the casting technique more challenging for the manufacturing of closed deck cylinder blocks.

A stationary model of a car air conditioning system was developed to evaluate refrigerant, mechanical power and all the fluid properties along the circuit. The model requires only the characteristics of the constituents, which are normally available from suppliers. This approach enables estimation of system performance with satisfactory accuracy, already during the design approach, and allows to determine the most appropriate components in order to meet target requirements with a satisfactory balance of the refrigerant circuit.

The aim of this work is to validate a BE numerical methodology to calculate how the acoustic properties of seats can affect the acoustic behaviour of the passenger compartment of a vehicle. An analytical model, based on the Delany and Bazley approach, was implemented in order to simulate the acoustic impedance of the foam-fabric system. This model has been validated with absorption coefficient measurements on a certain number of foam-fabric combinations. The calculated impedance was used as input for a BEM analysis of the interior cavity of a trimmed vehicle. The measured impedance of trimming components as floor carpet, door panels and parcel shelf were included into the cavity model. The acoustic field due to a known source with and without seats was calculated, in the frequency range 20-400 Hz: the calculated FRFs are in good agreement with the measured ones.

The complexity of environmental problem is characterised by the typical difficulty to find an unique quantitative measure for “being green”. Environmental damage cannot easily be compared with parameters such as cost or time that are “hard” metrics. However, techniques like Life Cycle Assessment should make it possible comparing products based on the basis of their environmental profile. In this study a modelled approach that allows to integrate Life Cycle Assessment considerations within multi-criteria analysis methodology is described: this integration is clearly exemplified by a simple software tool called ECOCOST. ECOCOST represents an effort to join different field of evaluation, other than environmental, to the Life Cycle Assessment: then environmental results emerged from LCA can be matched with other kind of evaluation, economical and technical in particular.

The Finite Element Analysis (FEA) is widely used in automotive industry for many applications, such as structural analysis, computational fluid dynamics (CFD), vibration behavior and acoustic properties, crashworthiness and, more recently, manufacturing process simulation. For all these FEA applications, accuracy is always a key issue. The analysis accuracy depends mainly on two factors: on one hand the FEA codes and on the other hand the definition of boundary conditions and material properties. Over the years, most FEA codes are well tested for accuracy through numerous benchmarks: therefore breakthroughs in further accuracy improvement from the aspect of FEA codes are difficult to achieve. On the other aspect, there is some room for FEA improvement by means of more accurate definition of material properties. In this paper, a new methodology for improving analysis accuracy by considering thickness variations of the component is proposed and validated using a structural body part.

The AICC is an assisting system for controlling relative speed and distance between two vehicles in the same lane. The AICC system may be considered as an extension of a traditional cruise control, not only keeping a fixed speed of the vehicle, but correcting it also to that of a slower one ahead. The main objective of this paper is to illustrate the design of the intelligent cruise control system involving the automatic control of throttle position and braking systems. There is much evidence nowadays that fuzzy approaches to real problems, where the linear control theory fails or can't provide an available and robust design solution, are often the best alternative to more familiar schemes.

The behavior of an automotive dashboard has been evaluated using mathematical FEM models in combination with explicit structural codes in accordance with EEC homologation test 78/632. The test simulates the impact of the human head against the dashboard which can occur during a front crash. The simulation of the impact phenomenon in the basic dashboard configuration was examined as related to a series of design variants elaborated to eliminate critical areas. Variations in the stresses were determined in the component in reference to the basic model. An indispensable premise to achieving these results was the execution of FEM process simulations aimed at obtaining the actual distribution of the mechanical strength properties, which were weighted according to the localized influence of different temperatures and flow stresses during injection.