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An effective program for external noise reduction of vehicles was firstly established in Brazil by an agreement between ANFAVEA and CETESB in the beginning of last decade. IBAMA worked this proposition and published in 1993 the first CONAMA Resolution, including the pass-by noise limits and the deadlines to satisfy the new sound pressure levels. Since then, CONAMA is responsible for this subject. In 2001 lower levels were imposed, similar to those existing in Europe, with 2006 as the deadline for all vehicle families. The paper describes and gives and overview of the procedures, the acoustic technologies and improvements developed to achieve, in two steps, the new limits, mainly for commercial vehicles, like heavy trucks {from 92 dB(A) to 80 dB(A)} and passenger cars {from 84 dB(A) to 74 dB(A)}. We enumerate also the non-acoustic problems solved, for instance the thermal problems, due to the acoustic barriers applied to reduce pass-by noise.

In order to attend the more demanding expectations of the commercial vehicles customers, it is being looked for improvements in order to reach better comfort on driving. Among the systems that interact with the driver, the shifting system can be distinguished. The development of a commercial vehicle shifting system is getting complex, because besides making possible the gear changes, it should follow comfort, ergonomics and durability parameters, balancing the necessary robustness for heavy applications with the shift smoothness desired by the user. At the start of the development of commercial vehicles shifting systems, the concept to be applied is analyzed, defining the model. Then it starts the study of the system construction, according to layout parameters of the vehicle project. This stage is predominantly accomplished by computer models. Then the prototypes are manufactured, in which functional tests are made for refinement.

The purpose of this paper is the presentation of the main experiences of customers and users of trucks and buses regarding the electronic systems placed in these vehicles, specially in the Latin American market. Basically, in the past years the number of on-board electronic devices increased a lot and the evolution of the customer know-how concerning the new technologies is in progress. Therefore, a line between the mechanical engine and the electronic vehicle management will be traced on this paper, considering the time the customers have taken to react regarding the applied innovations.

This paper intends to show how Telematics has started in Brazil and describe its impact in the traditional way of making Business with commercial vehicles. We want to make a brief comment about the main enabling technologies for the Telematics improvement: Telecom infrastructure: the investments after the privatisation of the sector, as well, trends for new services (WAP, SMS, Tracking, etc); Internet infrastructure: the growing of internet accesses and its impact in the industrial economy; The impact of these new technologies in the trucking Business and how Brazil is prepared for. New investments that are coming; The impact of IT technologies in the Brazilian GIP (Gross Internal Product) and in the Transportation market.

The objective of this paper is to present the update procedures and the future tendencies for the diagnosis projects in commercial vehicles, specially buses and trucks. The constant increase in the number of components and electronic systems in commercial vehicles demands that the subject “Diagnosis” be treated and previously defined, while the vehicle is in the project phase. The final goal of this thought is to provide to the vehicle the best possible acting of all the electronics systems placed in vehicle, and, as a consequence, the best running of the On-Board and Off-Board diagnosis systems which should assist the customer needs directly. The tendency is to project the vehicles of the same brand in the same conceptual line facilitating the assembly work in production line and the after sales support.

The objective of this paper is to present the update procedures and the future tendencies for the diagnosis projects in commercial vehicles, specially buses and trucks. The constant increase in the number of components and electronic systems in commercial vehicles demands that the subject “Diagnosis” be treated and previously defined, while the vehicle is in the project phase. The final goal of this thought is to provide to the vehicle the best possible acting of all the electronics systems placed in vehicle, and, as a consequence, the best running of the On-Board and Off-Board diagnosis systems which should assist the customer needs directly. The tendency is to project the vehicles of the same brand in the same conceptual line facilitating the assembly work in production line and the after sales support.

Because of the increasing need to reduce the time of development of new products, or even to evaluate the reliability of products, one has been noticing a trend to rationalize field tests through essays in ever more representative test benches, within a shorter period of time at a lower cost. In the automotive industry, the trend is to increase the reliability of tests in benches. The quantity of simulated parameters is increasing, what demands an ever increasing survey of data based on measurements of signals of deformation of leaves of spring leaf and courses of suspension in experimental vehicles.

This paper presents in a chronological way the main parameters used for automotive vehicles concerning acoustic qualification/quantification. We start with the loudness concept, pass by the “A” weighting philosophy and arrive to the sound level reduction including sound quality. We are able to show a lot of parameters, each one trying to match better the correlation between objective results and subjective evaluations. We mention several aspects regarding the human ear that make difficult the description of sound sensations through a single parameter. We emphasize also the absence of the exposure time in the parameters used to evaluate acoustic comfort. It is shown the large gap between the parameters used in lab and those applied in the legislations through some standards. Some conclusions are presented and the future related to acoustic parameters are discussed.

Due to the growing need to reduce the development time of new products, a tendency to rationalize field tests through test benches, in shorter times and with lower costs, has been noted in recent years. During the 90's, such a tendency has generated, in the automotive industry, a great effort to substitute classic field tests, which until recently represented 70% of the development work, for bench tests, with benches well “calibrated” in relation to the traditional methodology. The present work intends to show the development of a test bench to simulate solar radiation and relative humidity effects upon parts and interior lining materials of truck cabins. The traditional test was carried out exposing the cabin to weather conditions in predetermined locations, or in a hot-house, monitoring the cabin interior for temperature and relative humidity variations.

Recent studies in the USA show 2800 passenger casualties/year, due to automobiles and light vehicles impacting against the front structure of medium and heavy trucks at speeds over 45 mph. This same driver or passenger leaves the vehicle and becomes a pedestrian. What is being done in the automotive industry to face this situation? What improvements can be expected in automobiles, trucks and buses in the XXI century? The results obtained in this work show that it is possible and very important for new projects and modernization of commercial vehicles (trucks and buses) to introduce a front bumper concept foreseeing the Passive Safety of third parties (passenger vehicles).

Vehicle Safety is very attractive, concerning active or passive safety. The collisions are intensively studied including deformations, kinematics, protections, devices and injuries. By the way, today we have a lot of computer programs trying to simulate these crash-tests. But, we can have an idea about the magnitude of the impact forces of a vehicle against a rigid wall starting from known physical concepts and simplified approximations. This is one of the purposes of this work. The classic problem of projectile impacts against a rigid wall and the example of an aircraft impact against a nuclear power plant are used to consider the models applied to vehicles. We consider the disacceleration of a material point and also the vehicle as an extense object. Real data are used to quantify the achieved expressions. We compare and discuss the magnitude of the forces, for instance, between a passenger car and a commercial vehicle.

The paper describes the acoustic development effected in one middle-class commercial vehicle with the purpose of achieving the external sound pressure levels dictated by new Brazilian legislation. The philosophy adopted as well as the mandatory modifications of the truck to fulfill the noise limits are showed together with the non-acoustic characteristics. Besides the acoustic treatment of some specific sources, it was introduced an acoustic barrier, usually called capsule or shield to reduce the noise emission of the engine-transmission assembly working by the mass law principle and sound absorption.

We are living an ecologic decade. The aspects concerning comfort and safety are emphasized, including also the commercial vehicles. The interaction between mass-machine-environment is very important. The acoustic comfort belongs to this context. This paper presents the acoustic development relative to the internal noise reduction of a road bus. The internal noise of automotive vehicles is composed by two parcels: the structureborne noise, which is characterized by the low frequencies and the airborne noise which arrives at the passenger compartment passing directly through the divisory between passenger compartment and engine compartment; this path is preferred by the high frequencies. In this work we present the technics we have applied to reduce noise coming from both paths. The quantification of the obtained results is elaborated through the measurements of sound pressure levels, specially the weighting curve “A” for the overall noise.