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Design and Sustainability Assessment of Lightweight Concept for an Automotive Car Module

Universita degli Studi di Firenze-Massimo Delogu
Benteler-Joern Toelle
  • Technical Paper
  • 2020-37-0033
To be published on 2020-06-23 by SAE International in United States
Recently sustainability has become a priority for industry production. This issue is even more valid for the automotive sector, where Original Equipment Manufacturers have to address the environmental protection additionally to traditional design issues. Against this background, many research and industry advancements are concentrated in the development of lightweight car components through the application of new materials and manufacturing technologies. The paper deals with an innovative lightweight design solution for the bumper system module of a B-segment car. The study has been developed within the Affordable LIght-weight Automobiles AlliaNCE (ALLIANCE) project, funded by the Horizon 2020 framework programme of the European Commission. A bumper demonstrator, that is currently in series production and mainly consists of conventional aluminum materials, is re-engineered making use of 7000 series aluminum alloys. The design alternatives are described and assessed regarding the achieved weight saving. The study is complemented by a sustainability assessment of the different modules performed through the Life Cycle Assessment methodology. The analysis takes into account production, use and End-of-Life stages and the results are expressed in terms…
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The Influence of Autonomous Driving on Passive Vehicle Dynamics

SAE International Journal of Vehicle Dynamics, Stability, and NVH

Universita degli Studi di Firenze-Tommaso Novi, Renzo Capitani
Danisi Engineering S.r.l.-Marco Fainello, Giacomo Danisi
  • Journal Article
  • 2018-01-0551
Published 2018-04-03 by SAE International in United States
Traditional vehicles are designed to be inherently stable. This is typically obtained by imposing a large positive static margin (SM). The main drawbacks of this approach are the resulting understeering behavior of the vehicle and, often, a decrease in peak lateral grip due to oversized rear tire characteristics. On the other hand, a lower SM can cause a greater time delay in the vehicle’s response which hardens the control of a vehicle at limit handling for a human being. By introducing advanced autonomous driving features into future vehicles, the human factor can be excluded in limit handling manoeuvers (e.g., obstacle avoidance occurrences) and, consequently, the need for a high SM (i.e., high controllability for human drivers) can be avoided. Therefore, it could be possible to exploit the passive vehicle dynamics and enhance the performance, both in terms of peak grip and transient response.The goal of this article is to explore if a decrease in SM can lead to a performance advantage on an obstacle avoidance manoeuver when the vehicle is driven by a robotic controller.…
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Development of an e-LSD Control Strategy Considering the Evolution of the Friction Torque with the Wear Depth

SAE International Journal of Engines

Universita degli Studi di Firenze-Amedeo Tesi, Francesco Vinattieri, Renzo Capitani
Meccanica 42-Claudio Annicchiarico
  • Journal Article
  • 2016-01-1136
Published 2016-04-05 by SAE International in United States
The Electro actuated Limited Slip Differential (e-LSD) can help increasing the dynamic features of the vehicle, but to implement a well designed control logic it is necessary a deep knowledge of the actual friction torque built up by the differential clutch. This work presents the development of such a control law that takes into account the wear depth progression. To carry out this task, an alternative method has been used to study the clutch discs engagement depending on the wear rate.The method takes advantages from a mixed approach with a numerical and an experimental part. Using a general purpose block-on-ring test bench, the tribologic analyses were performed following the ASTM G77 standard; thus, the friction coefficient has been investigated in the contact between discs with molybdenum treatment and steel alloy discs, as well as its variation depending on the wear rate. The results were input in a numerical algorithm aimed at evaluating the friction torque of the clutch as a function of the pressure and the wear depth. The results, besides providing useful hints for…
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Target setting and structural design of an EPS-in-the-Loop test bench for steering feeling simulation

Universita degli Studi di Firenze-Francesco Vinattieri, Renzo Capitani
Danisi Engineering S.r.l.-Tim Wright, Giacomo Danisi
Published 2016-04-05 by SAE International in United States
The adoption of Electrical Power Steering (EPS) systems has greatly opened up the possibilities to control the steering wheel torque, which is a critical parameter in the subjective and objective evaluation of a new vehicle. Therefore, the tuning of the EPS controller is not only becoming increasing complicated, containing dozens of parameters and maps, but it is crucial in defining the basic DNA of the steering feeling characteristics. The largely subjective nature of the steering feeling assessment means that EPS tuning consists primarily of subjective tests on running prototypes. On account of that, this paper presents an alternative test bench for steering feeling simulation and evaluation. It combines a static driving simulator with a physical EPS assisted steering rack. The end goal is to more accurately reproduce the tactile feedback to the driver by including a physical hardware in lieu of complicated and difficult to obtain software models. The focus of the activity in this paper was to define the specifications for this test bench and to entirely design it.The test bench contains some actuators…
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Torque Vectoring of a Formula SAE through Semi Active Differential Control

Universita degli Studi di Firenze-Claudio Annicchiarico, Renzo Capitani
Published 2014-11-11 by SAE International in United States
In a Formula SAE car, as for almost all racecars, suppressing or limiting the action of the differential mechanism is the technique mostly adopted to improve the traction exiting the high lateral acceleration corners.The common Limited Slip Differentials (LSDs) unbalance the traction torque distribution, generating as a secondary effect a yaw torque on the vehicle. If this feature is electronically controlled, these devices can be used to manage the attitude of the car.The yaw torque introduced by an electronically controlled LSD (which can also be called SAD, “Semi-Active Differential”) could suddenly change from oversteering (i.e. pro-yaw) to understeering (i.e. anti-yaw), depending on the driving conditions. Therefore, controlling the vehicle attitude with a SAD could be challenging, and its effectiveness could be low if compared with the common torque vectoring systems, which act on the brake system of the car. In addition, unlike common ESC (“Electronic Stability Control”) systems do, a SAD can modify the vehicle attitude without limiting its traction performance, which is a crucial factor for racecars.This paper shows the SAD designed at the…
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An Innovative Solution for Two-Stroke Engines to Reduce the Short-Circuit Effects

Universita degli Studi di Firenze-Giovanni Ferrara, Francesco Balduzzi, Giovanni Vichi
Published 2012-04-16 by SAE International in United States
Two-stroke engines complete the process cycle in one crankshaft revolution: the scavenging process takes place when the piston is close to the bottom dead center, with the opportunity to open and close the cylinder ports by means of the piston motion, greatly reducing the number of moving parts. This solution however, typically used in small engines, imposes a symmetrical timing with respect to the bottom dead center, leading to a lower scavenging efficiency than a four-stroke engine.Except for the short rpm range of dynamic tuning, two-stroke engines are affected by the short-circuit of fresh air-fuel mixture during the scavenging process: this phenomenon results in a fuel loss, subsequent lower torque and higher specific consumption, and also in an inevitable increase in pollutant emissions.This paper presents one possible mechanical solution to reduce the short-circuit in the whole rpm engine range, to keep the typical advantages of two-stroke engines (simple construction, high specific power and working regularity for a single cylinder engine of a given displacement) and, at the same time, to avoid the usual problems of…
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Design of an Active Vehicle System for a Hybrid Race Car

Universita degli Studi di Firenze-Claudio Annicchiarico, Silvano Cappelli, Lorenzo Gasperini, Tommaso Innocenti, Renzo Capitani
Published 2011-09-11 by SAE International in United States
The aim of this work is to define the core of a stability control, called Active Vehicle System, for a hybrid Formula SAE car that will compete in the next season in the upcoming Alternative Energies (Class 1A) class. The vehicle on which the control system will act is equipped with two electric motors on the front axle and an internal combustion engine connected to the rear axle by the way of a semi-active differential. The layout of the car under consideration has been defined with the purpose of getting the most effectiveness by the Active Vehicle System, whose role is to define a yaw torque to be applied to the vehicle in order to correct its behavior during each maneuver. The results of the Upper Controller will be actuated by two Lower Controllers, one dedicated to the electric motors and one to the semi-active differential. On such controlled vehicle some testing maneuvers have been performed, in order to check its functionality. The analyses have been done with a mathematical model of the vehicle, in…
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