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Since the Weber-Fechner Law (1860) until 1950 there was no trustful method to calculate Loudness of complex sounds. At that time, ISO proposed three weighting curves, A, B and C based on rough approximations of the isophonic curves, 40, 70 and 100 phons. It was supposed to be a temporary suggestion. Curves B and C were abandoned, but A weighting survives until today! In 1957, Stevens and Zwicker presented two independent methods to obtain Loudness in sones, based on the new Stevens' Power Law. In 1965, Kryter introduced Noisiness in noys. Stevens in 1975 presented Perceived Magnitude as an improvement of Loudness calculation. In these acoustic parameters, the sound pressure levels per frequency band are transformed into acoustic sensation levels, and through the sensation spectrum the magnitude of the overall sensation is calculated. The A, B and C curves, for low, moderate and high levels do not follow this concept.

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.

Loudness of sounds is often assumed to be an adequate indicator of the unwantedness, for general noise control purposes, of sounds. Experiments have shown, however, that for many sounds there are differences between some physical aspects of sound, and judgements of Loudness (soft/loud) compared to judgements of Noisiness (acceptable/unacceptable), which is sometimes called Perceived Noise or Perceived Noise Level, depending on the units used. Internal sound pressure level of two sets of vehicles, commercial and passenger cars, are used to calculate the acoustic parameters: Loudness in sones, according to Stevens and Noisiness in noys according to Kryter. The calculations are similar, but Kryter's Equal Noisiness Contours emphasize the high frequencies. We look for the degree of linear correlation of these acoustic parameters, applying to the experimental data least squares curve fittings. In addition we establish a ranking for both parameters using a specific set of vehicles.

The paper looks for the degree of linear correlation of some acoustic parameters concerning Speech Intelligibility in vehicles. The Articulation Index (AI) was originally a criterion to characterize the influence of parasite noise on the Intelligibility of a conversation in the design of speech communication systems. Introduced in the automobile acoustics, it is more and more commonly used by vehicles manufacturers to estimate the middle and high frequency content of spectra noise inside various types of vehicles driven under several running conditions. The correlation with Speech Intelligibility, measured through subjective measurements is well known. Presently we have more sophisticated parameters like STI, RASTI, SII… directed mainly to architectural acoustics and sometimes used in vehicle acoustics. They require specific hardwares and softwares and are more complicated to deal with and often are called machine measures of Speech Intelligibility.

Since the rising of the automotive industry, the concern with the driving itself has been the main task of the developments, which have improved the safety-related vehicle systems, such as headlamps and signalling devices that have received significant investments in technology. The paper deals with some functional and durability tests applied to illumination and signalling devices used in the automotive industry. We describe some durability tests like: vibrations, sealing tests, vehicles tests, …… emphasizing the research regarding headlights internal pressure variations relative to the protection against adverse environmental conditions. Concerning functional tests we focus those related to Photometry and Colorimetry, using Psychophysical parameters and the CIE International System XYZ (Commission International de l'Eclairage).

When a new commercial vehicle project begins or some changes are necessary in the current products, the development of clutch pedals has a strong dependence with the powertrain characteristics which generally affects the clutch behavior and its actuation system. Although theoretical analyses are always taken into consideration, experimental procedures in bench tests and vehicles play an important role in the determination of new configurations for the clutch actuation system. Nowadays cost reduction, unification and quality gains must be considered in the project and development process. The above considerations mean that the work in bench tests regarding clutch actuation systems must be emphasized to simulate their behavior in the vehicle.

Approximately 50% of the industrial processes are related to the measurement and control of temperature. The automotive industry often uses thermocouples, transducers that work according to thermoelectric principles. For higher measurement reliability it is necessary to calibrate these transducers, preferably at low cost. The thermal laboratory at DCBR is developing calibration procedures and the evaluation of associated uncertainties. The object of this article is to present the thermocouple calibration process among other transducers and specially the importance of their vehicle application.

The paper looks for the degree of linear correlation of some acoustic parameters when their results are compared taking into consideration the internal noise of a set of passengers cars and another set of commercial vehicles. The acoustic parameters dealing with the overall noise (Loudness, dB(A) and dB(B)) and those related to the high frequency portion of the spectrum (Articulation Index and Sharpness) are chosen. The sound pressure levels in the passenger compartment are measured according to ISO 5128. The parameters are calculated in some specific velocities. A least square fit to a straight line to each pair of the acoustic parameters is applied. The results are discussed taking into consideration the degree of correlation trying to investigate how dependent or independent the parameters are. In addition it is possible to see the fluctuation range of these parameters concerning each set of vehicles.

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.

The conventional and fixed maintenance intervals planned according to the vehicle application group (rough operating condition, short haul and long haul) are substituted by computed intervals, which correspond to the real components wear. The system carries out the prognosis of different services for periodic maintenance, indicating in the instrument cluster the dates when the services should be carried out as well as the remaining distance for carrying out each service. The system allows to join all different maintenance dates to only one date, improving the vehicle programming. The FSS totally integrated with CAN (Controller Area Network) line through a telematic system can centralize all maintenance prognoses in the transport company. Using this system, the user can reduce all documents and maintenance vehicle controls.

Competition in Automotive Market is driving the need for more time - and cost - effective testing methods. In the fatigue life analysis of new passenger and commercial vehicle designs, laboratory testing through servohydraulic equipment plays a very important role. In DaimlerChrysler do Brasil, the Durability Test Laboratory represents an important basis to assure high endurance reliability for all kinds of our commercial vehicle applications. In order to respond to the above mentioned testing tasks, this paper will focuse what we call our “New Policy of Durability Tests for Commercial Vehicles”, based on development of simple and low cost Road Simulators, fully dedicated and customized to testing of vehicle components and chassis. Experimental results as well as other data related to consumption of laboratory's: area, utilityes, pressurized hoses and test time, will be used in order to illustrate advantages and disadvantages of the new testing resource.

With the increasing necessity of reducing the development time of new products, and also the need to evaluate product reliability levels, a trend to rationalize field tests through test benches has been noted. These tests have proved more and more representative and carried out in much lower times and with lower costs. In the automotive industry this trend has generated considerable effort towards making these bench tests more representative of actual conditions towards the increase of their reliability. The quantity of simulated parameters is growing and it becomes necessary to collect more data from ground measurements signal (acceleration, temperature, pressure, flow, etc.) in experimental vehicles.

During the last years, DaimlerChrysler do Brasil (DCBR) has been moving ahead in order to research and to develop an Automatic Vehicular Location System (AVL System) due to the increase of the security through blocking and tracking devices, monitoring and mainly, logistic solutions that includes maintenance and fleet management. DaimlerChrysler do Brasil faced the necessity to prepare a test that could reflect a real situation, not only to try the system's features regardless communication and management of transmitted data, also however, to ensure the durability and reliability of the on-board vehicles equipment focusing on Brazilian Infrastructure. The objective of this paper is to describe the methodology, used tools and acquired results obtained by DCBR improvement test of his AVL System, throughout the “9o Rally Internacional dos Sertões - 2001”.

The paper goes beyond the conventional way of looking at Loudness. We go into the calculation procedures taking into consideration two methods coming from the work of two researchers: Zwicker and Stevens. These methods are described in ISO 532. Instead of going to the traditional way of comparing the overall noises we penetrate in the calculation processes, step by step, getting subsidies to analyze the contributions of each frequency band. We applied the two methods using some random sound pressure spectra we generated. We are able to compare the total Loudnesses in both methods using a least-square fit with linear approximation. The spectra of contributions in sones in third-octave bands are also compared for both methods, through the development of simple mathematical expressions which are able to identify the parcel correspondent to each third-octave band.

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.

In the work presented to SAE in 1999: IQTC: a Practical and Unified Index to Evaluate the Continuous Improvement of Suppliers, we showed that the Development Area is one of the chapters inserted into the evaluation process of suppliers and answers for an evaluation called IQDP (Quality Index in Product Development). The present work objective is to show the difficulties found in the implementation, solutions and improvements that are being used to outline a better supplier evaluation. Such a control within a universe of 350 suppliers (directly connected to production) being evaluated by 400 persons, in a natural process, is not an easy task. Collecting information about the difficulties faced to evaluate a supplier and the supplier claims to obtain an answer in reply to the attributed scores, took us to the search of the adequate computerized technology that would allow us to group the interests of work methods that would comply with the diverse demands involved.

This paper goes beyond the usual Loudness and make the introduction of a new parameter called Perceived Magnitude, developed by Stevens, as an improvement to qualify/quantify acoustic sensations. As a pioneer application we have applied it to quantify some acoustic sources associated to automotive industry. We emphasize the differences concerning Loudness and Perceived Magnitude, and show the right way to compare the results. The sound pressure level spectra of some sources in octave bands are used to calculate the overall noise in SONES associated to the above parameters as well the usual dB(A). A suggestive and innovative spectral composition weighted by the above functions is introduced to interpret the results. Finally we discuss the benefits we can achieve using the new parameter in vehicle acoustics.

Several automotive electrical systems can be analyzed and optimized using circuit simulators and simple equivalent circuits. However, there are several cases in which it is easier to include data collected from experimental measurements such as very complex waveforms derived from electrical conducted noises. The objective of this work is to show how to improve the accuracy of the simulations by importing experimental data such as voltage waveforms generated by solenoid valves while switching off. Nowadays, due to the storing features already available on modern measurement systems, this procedure is easier, allowing the recording of the measured data in simple computer files (usually in ASCII format).