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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 importance of the numerical simulation and testing techniques for the software specifications development of on-board automotive systems design is the paper main issue. In order to promote flexible and rapid procedures improving software specifications, new methodologies are necessary. The proposed procedure is based on the design, simulation, validation, software compiling and rapid prototyping algorithms concerning management strategies of automotive electronic systems. The new feature of this methodology is provided by the comparison between two prototyping environment outputs: rapid prototyping tool outputs represented by strategies running in DSpace® using powerful microprocessors and CPU outputs characterized by limited calculation resources of an almost real one.

This article describes an application of sliding mode techniques to the design of an air/fuel ratio control system for a 4-stroke engine, to minimize exhaust gas and emissions. This technique allows to achieve good control performance in terms of precision, robustness, and fast transient response. To support sliding mode control a second PI stage was added, based on the signal of a second oxygen sensor installed after the catalytic converter. Experimental results were better than those obtained with a conventional PI control, currently used on production applications. The new control algorithm (sliding mode based on the first oxygen sensor, and PI on the second) is very versatile because the approach chosen allows to calculate the parameters values for the ECU using computer simulation.

Autonomous Driving is one of the main subjects of academic research and one important trend in the automotive industry. With the advent of self-driving vehicles, the interest around trajectory planning raises, in particular when a customer-oriented analysis is performed, since more and more the carmakers will have to pay attention to the handling comfort. With that in mind, an experimental approach is proposed to assess the main characteristics of human driving and gain knowledge to enhance quality of autonomous vehicles. Focusing on overtaking maneuvers in a highway environment, four comfort indicators are proposed aiming to capture the key aspects of the chosen paths of a heterogeneous cohort. The analysis of the distribution of these indicators (peak to peak lateral acceleration, RMS lateral acceleration, Smoothness and Jerk) allowed the definition of a human drive profile.

Natural gas is a promising alternative fuel for internal combustion engine application due to its low carbon content and high knock resistance. Performance of natural gas engines is further improved if direct injection, high turbocharger boost level, and variable valve actuation (VVA) are adopted. Also, relevant efficiency benefits can be obtained through downsizing. However, mixture quality resulting from direct gas injection has proven to be problematic. This work aims at developing a mono-fuel small-displacement turbocharged compressed natural gas engine with side-mounted direct injector and advanced VVA system. An injector configuration was designed in order to enhance the overall engine tumble and thus overcome low penetration.

Handling behaviour is a very important aspect of modern cars, which need to reach high levels of lateral acceleration maintaining good stability and driveability. The presence of an AWD powertrain changes the response of the vehicle and then it is very important to qualify the car behavior in terms of perceived performances through objective indexes. The paper presents the development of evaluation criteria for AWD vehicles objective assessment; simulation tools and SW standard procedure has been optimised for AWD performances virtual evaluation and different architectures (locking, self-locking, visco-coupling, active differentials) are compared in terms of longitudinal, lateral and cross-coupling dynamics performances. Through the proposed methods it is possible to make vehicle system analysis using simulation model and standard procedures to classify different AWD architectures.

One of the way for improving environmental performances of car propulsion system is the adoption of hybrid systems where the internal combustion engine (ICE) is coupled or temporary overtaken by an electric motor. The reference prototype of this article is the FIAT Multipla Hybrid where are possible three functional modes: Pure Electric mode, Serial Hybrid and Parallel Hybrid. Particularly it was approached the torque splitting algorithm applied to the parallel hybrid one; the work was first tested in simulation, after implemented in the electronic control units and finally tested on the field using the test bench of the 10 hybrid vehicles that belongs to the Atena Project [1].

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.

In order to describe simultaneously the thermo-fluid dynamics and the acoustics of an Internal Combustion engine, a mathematical model and a computer program has been developed which integrate the Method of the Characteristics with the Acoustic. Transfer Matrix Method. The former method is currently used to model the fluid dynamics of Internal Combustion engines, whilst the latter allows the description of the acoustical behaviour of the intake and exhaust systems. The theory presented in the article integrates the two approaches, allowing the fluid-acoustics of the global system engine-silencers to be described, taking into account the mutual interactions. Preliminary investigations on a simplified system, constituted of a constant section duct, have demonstrated the consistency and validity of the model.

One of the objectives of the Atena project was the definition of methods for the predictive evaluation of the environmental impact of different types of vehicles used in an urban scenario. The target is to obtain a methodology that allows the decision maker to verify in simulation the effects of possible measures like the law enforcement to the access restrictions or vehicle fleet composition. The main obstacle is the realization and managing of real driving cycles in order to overtake the limits derived from the utilization of typical cycles (i.e., ECE + EUDC) or the simple consideration of average speed. The starting point is a digital representation of the urban network where all the roads are represented with one or more arcs and for all these arcs are available an estimation of the traffic variables like the vehicle flow (vehicles per hour) or the average speed (kph). Every arc is described in terms of traffic parameters like the type of road (i.e., highway, district road).

Centro Ricerche Fiat in collaboration with Fiat Auto vehicle test department has developed a numerical-experimental procedure in order to support on-road development and fine tuning of a new car with electric power steering. The integration of an electric power steering model, given by the supplier, in a full vehicle model, in order to evaluate steering feel objective quality indices, has allowed to improve vehicle performance in term of steering feel and reduce on-road development time.

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.

The paper presents the results of the STYFF-DEXA project which has delivered an attractive computational approach based on detailed treatment of the filtration and regeneration processes inside diesel particulate foam filter materials. The new approach can provide accurate macroscopic material parameters by utilizing tomographic data and novel algorithms to reconstruct three-dimensional digital representations of the foam material microstructure. The Lattice-Boltzmann (LB) Method is used as a basis for computing the flow within the foam pores. The latter is coupled to sub-models of particle transport/deposition and size distribution based on the very efficient Method of Moments which employs a probability density function representation of the suspended soot. Additionally, acoustics modelling functionality has been developed which permits the evaluation of the engine noise attenuation capabilities of the foams and similar microstructures.