Lorenzo Morello's research while affiliated with Politecnico di Torino and other places

Publications (54)

Chapter
As explained in the first volume, initially motor vehicles adopted the basic configurations which had been used since millennia for animal traction vehicles. Since the fourth millennium BC there were two wheeled carts and four wheeled wagons: the former were used for lighter loads and, above all, when speed and maneuvrability were important, while...
Chapter
Books about automotive chassis design usually do not include a discussion about car prime movers and their energy sources, which are dealt with in details in books devoted to the study of engine or electric systems design. Nevertheless the opinion of the authors is that is quite impossible to design the performance of a chassis in terms of longitud...
Chapter
The aim of the European Union’s policy in the automotive sector is to legislate the internal market for vehicles and ensure a high level of environmental protection and safety, to strengthen competitiveness, and to provide a stable playing field for the industry. The technical harmonisation of motor vehicles allows car manufacturers to access as la...
Chapter
Data reported in this chapter were mainly extracted from institutional documents of ANFIA, ACEA, ISTAT and Eurostat.
Chapter
The study of braking on straight road is performed using mathematical models similar to those seen in Chap. 23 for longitudinal dynamics. But in this case, the presence of suspensions and the compliance of tires are neglected and the motion is described by the longitudinal equilibrium equation (23.1) alone.
Chapter
When computing the performance of a vehicle in longitudinal motion (maximum speed, gradeability, fuel consumption, braking, etc.), the vehicle is modelled as a rigid body, or in an even simpler way, as a point mass.
Chapter
A vehicle on elastic suspensions may be modelled as a system made by a certain number of rigid bodies connected with each other by mechanisms of various kinds and by a set of massless springs and dampers simulating the suspensions. A vehicle with four wheels can be modelled as a system with 10 degrees of freedom, six for the body and one for each w...
Chapter
The take-off manoeuvre of a vehicle was studied in Sect. 23.9 using a simple model where the inertia of both engine and vehicle were modelled as two flywheels connected to each other by a rigid shaft and a friction clutch. This model can be made more realistic by adding the torsional compliance of the shaft, of the joints and possibly the gear whee...
Chapter
The models seen in the previous chapters dealt with vehicles that maintain their symmetry plane more or less perpendicular to the ground; i.e. they move with a roll angle that is usually small. Moreover, the pitch angle was also assumed to be small, with the z axis remaining close to perpendicular to the ground. Since pitch and roll angles are smal...
Chapter
Chassis structures are stressed by internal and external loads.
Chapter
An increasingly competitive automotive market offers its products to increasingly demanding customers. Numerous standards and rules, primarily regarding safety and environmental impact, are issued by regulating bodies and governments, making today’s vehicles more and more complex.
Chapter
Low speed or kinematic steering is, as already stated, defined as the motion of a wheeled vehicle determined by pure rolling of the wheels. The velocities of the centres of all the wheels lie in their midplane, that is the sideslip angles \(\alpha _{i}\) are vanishingly small. In these conditions, the wheels cannot exert any cornering force to bala...
Chapter
For vehicle suspensions we mean a mechanism which links the wheel to the body directly or to a frame fixed to the body.
Chapter
This chapter is dedicated to control systems working on steering mechanism, brakes and elastic and damping elements of suspensions; sections are divided according to this classification.
Chapter
As already stated, a road vehicle on pneumatic tires cannot maintain a given trajectory under the effect of external perturbations unless managed by some control device, which is usually a human driver. Its stability solely involves such state variables as the sideslip angle \(\beta \) and the yaw velocity r
Chapter
In the first case the kinematic constraint exerts all forces needed to modify the trajectory without any deformation, i.e. is assumed to be infinitely stiff and infinitely strong. A perfect kinematic guidance is therefore an abstraction, although it is well approximated in many actual cases.
Chapter
In this chapter we will discuss about design rules and procedures for those transmission components, we have not considered in previous chapters yet, and about test methods applied for validation and qualification.
Chapter
Mechanical devices that enables the driver shifting the pair of gearing wheels in such a way as to obtain the desired transmission ratio, are called shifting mechanisms. They are called internal if they are contained in the gearbox casings; they are called external when they mounted partly on the gearbox, partly on the vehicle body and connect the...
Chapter
Opposite to manual gearboxes, automatic gearboxes show a wide diversity of technical solutions; this situation could demonstrate the fact that this gearbox doesn’t have reached his technical maturity yet.
Chapter
It is always arduous to decide if historical notes should come before or after the description and the interpretation of the state of the art.
Chapter
The braking system must accomplish three different jobs: to completely stop the vehicle; this function entails braking moments on the wheel as high as possible; to allow speed control, when the natural deceleration of the vehicle, due to mechanical friction and motion resistances is not enough; this function entails braking moments on the wheels no...
Chapter
Gearbox and clutch, or other start-up devices used as alternative, are essential to obtain from a reciprocating internal combustion engine a driving torque suitable to traction.
Chapter
In clutches friction is applied to transmit the torque between an input and an output shaft. It is built with three discs; two of them are connected to the engine crankshaft and one, between the other two, is connected to the gearbox input shaft. These discs are respectively named driving plates and driven plate.
Chapter
Synchronizers function is to enable changing of meshing gears couple, on a moving vehicle without negative consequences on mechanical integrity and on interior noise. During synchronization the clutch must be disengaged.
Book
This textbook draws on the authors’ experience gained by teaching courses for engineering students on e.g. vehicle mechanics, vehicle system design, and chassis design; and on their practical experience as engineering designers for vehicle and chassis components at a major automotive company. The book is primarily intended for students of autom...
Book
This textbook draws on the authors’ experience gained by teaching courses for engineering students on e.g. vehicle mechanics, vehicle system design, and chassis design; and on their practical experience as engineering designers for vehicle and chassis components at a major automotive company. The book is primarily intended for students of automotiv...
Chapter
Gearboxes are normally classified according to the number of gear wheel couples involved in the motion transmission at a given speed; in case of manual vehicle transmissions, the number of gear wheel couples to be taken into account is that of the forward speeds only, without consideration of the final ratio, even if integrated into the gearbox.
Chapter
The forces and moments a vehicle receives from the surrounding air depend more on the shape of the body than on the characteristics of the chassis. A detailed study of motor vehicle aerodynamics is thus beyond the scope of a book dealing with the automotive chassis.
Chapter
In the last 60 years the dominant model for mobility, and particularly for urban mobility, has been based on privately owned motor cars, where with this term we mean a four-wheeled vehicle propelled—in their largest majority—by an internal combustion engine operated on oil-derived fuels and fully controlled by a human being (mostly the owner of the...
Chapter
The definition of comfort in a motor vehicle is at once complex and subjective, changing not only with time (cars considered comfortable just twenty years ago are nowadays considered unsatisfactory) but also from user to user. The same user may change his appraisal depending on circumstances and his psycho-physical state. But comfort remains an inc...
Chapter
The goal of a system approach to vehicle design is to define the technical specifications of each component, in such a way that the vehicle, as a whole, performs its functions according to assigned procedures and objectives.
Chapter
Sometime, the names of differential, transfer box and final drive are used imprecisely; in addition to that these mechanisms are sometime integrated in the same subsystem in almost all possible combinations. We try to introduce some definition to better clarify this issue.
Chapter
Vehicle wheels have essentially two functions: to carry on the vehicle weight by exchanging vertical forces with the road surface; to exchange with the road surface longitudinal and side forces, able to move the vehicle and to control its path. As we have seen in the previous chapter the first function was already present on antique wheels that had...
Chapter
Transmission shafts are used to apply torque to those driven components whose rotation axis cannot be perfectly aligned with their driving counterpart.
Chapter
The structure of early cars consisted in a chassis and a body.
Chapter
The powertrain includes the engine, in modern cars mostly a reciprocating internal combustion engine, and the gearbox, that converts the engine torque into the torque needed for vehicle traction.
Chapter
As stated in Part II, two of the problems the automotive industry had to solve starting from the 1960s were related to the environmental impact due to the widespread use of road vehicles, in particular in highly populated areas like cities, and the use of energy, and in particular fossil fuels. Since then strict regulations have been imposed regard...
Chapter
As discussed in detail in Chap. 2, before the introduction of the unitized body, the term chassis was used to indicate a self-propelled system, sometimes capable of being driven, consisting of a load-bearing structure (a frame made of sidemembers and crosspieces) carrying the engine, the suspensions, the wheels, the driveline connecting the engine...
Chapter
The ideas that our way of providing mobility for most people—by producing cars and other vehicles suitable for private operation—are basically wrong, are not uncommon; these views are voiced strongly by a motivated and determined minority. These ideas are motivated by a variety of ideologies and political, economical or ethical beliefs, from sheer...
Chapter
Most motor vehicles need a transmission, since the speed requirements of the wheels are different from those of the engine. This is particularly true when the engine is a reciprocating internal combustion engine: in this case the transmission includes a start-up device (either clutch or torque converter), a variable ratio gearbox and the final driv...
Chapter
Motor vehicles must comply with the Technical Regulations applicable in the country they are offered for sale. In European Countries, compliance with the above Regulations, required to obtain European Certification, is verified through the Type Approval process performed by the manufacturer who must either test the car in front of the Government’s...
Chapter
For hundreds of thousands of years human beings lived without using any particular means of transportation. When they had to move an object, they simply lifted and carried it, if they were strong enough. If the object was too heavy, they arranged to drag it.
Chapter
Most road vehicles are powered by reciprocating internal combustion engines of either the spark ignition (SI or Otto-cycle) or the compression ignition (CI or Diesel-cycle) type. Moreover, almost all engines powering motor cars work following a four-stroke cycle sequence.
Chapter
This section deals with the evolution of the chassis subsystems in its broader meaning, and thus includes suspensions, steering system, wheels, tires, brakes and transmission systems. This order does not imply any priority, even if suspensions and steering system had a more significant influence on vehicle architecture and its evolution. The steeri...
Chapter
A description of how the automobile evolved from its very beginning to our days would not be complete without a description of the evolution of the technologies aimed to design and build this product and of the evolution of the related market. If this is true for any industry, this link between product, production process and market is even closer...
Chapter
At present, the large majority of road vehicles are powered by fossil fuels derived from oil, even if a growing number of electric vehicles and of vehicles powered by alternative fuels can be seen on the road. Since these alternative energy sources and vehicle schemes are more a perspective for the future than a reality of today, a thorough discuss...
Chapter
The evolutionary lines along which the future development of motor cars will proceed are well traced from some points of view and quite fuzzy from others. The problems the designer will face in the future have been known for decades and have not changed much in the past years, and the basic lines along which to look for adequate solutions are also...
Chapter
Technology evolves mostly by small incremental steps and, as stated in Part I, true revolution are quite rare. However, there are cases where a strong technology transfer occurs between different fields of technology, and this can cause sudden changes that are felt as true revolutions.
Chapter
In the last century, the automotive industry went through a number of deep transformations, developing from a group of minor mechanical shops, where the individual cars were crafted and repaired by hand, to the present-day situation.
Chapter
The car body is the external shell of the vehicle designed to accommodate and protect the people on board and their luggage from the external environment (unfavorable climate, noise, etc.) and the dangers motion may involve.
Book
The Automotive Chassis is the result of two decades of experience: On the one hand from the experience of teaching courses such as Vehicle Mechanics, Vehicle System Design, Chassis Design to engineering students; on the other hand from the design practice of vehicle and chassis components in a large automotive company. This work is addressed primar...
Chapter
Unlike their manual counterpart, automatic gearboxes employ a wide variety of technical solutions, a possible demonstration that this kind of gearbox has yet to attain his technical maturity. Automatic gearboxes were created for comfortable family cars with high displacement engines. They are now increasing their market share in small cars and spo...

Citations

... One of the purposes of body design is to achieve structural function, which is to support the vertical force due to the weight of the occupants as well as the mechanical components required for vehicle propulsion, control and other system [1]. Therefore, it endures mechanical stresses from several sources. ...
... De la jumătatea secolului al xviilea, termenul din franceză a fost împru mutat și în limba engleză, în forma chassis [4] (deși există și aici sinonimul frame), dar și în limba germană, chassis (alături de Fahrwerk [7]). o foarte frumoasă prezentare a influenței pe care dezvoltarea soluțiilor tehnice de realizare a automobilelor a avuto asupra înțelesurilor cuvân tului chassis din engleză se găsește în lucrarea [8]. în continuare, vom aminti și noi câteva dintre aceste considerații. ...
... However, as the speed increases, the acting forces become higher and tire slip begins to occur, as depicted in Fig. 2. Therefore, although the steering mechanism system is based on Ackermann's geometry, this linear dynamic is not accurate enough [54]. ...
... Rims determine whether the car will perform well and whether the drive will be comfortable. Hence, the selection of the appropriate rims for the car is crucial for best performance of the car [7]. Rim size can give the car an innovative aesthetic look. ...
... For continuous transmission types, e.g. variable pulley diameter systems, power losses are higher than with geared transmissions [22]. In modeling of such configurations, there are two options for efficiency calculation; fixed value or equivalent geared model. ...
... 1. Game Theory (Myerson (1991), Osborne and Rubinstein (1994), Bialas (March 2005), Patrone (2006), Fragnelli (2005), Cioni (2006), Cioni (2007a), Cioni (2008a) and Cioni (2008i)) as a tool for the description of the interactions among rational players with a full knowledge of the strategic situation; ...
... Also like its predecessor J. R. Choa and Al. (J.R. Choa, 2006) and subsequently (Morello, 2009) models the braking dynamics of vehicles by not sufficiently integrating the physical phenomena due to the ground-tyre interaction and limiting itself to the determination of the friction surface to the detriment of the work of deformation of the tyre and suspensions. However, Jr Choa's model, unlike Morello's, considers at least the pad pressure response on the brake system discs in the absence of pipe defects such as leaks and the like. ...