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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.

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).

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.

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 paper uses sets of experimental data, concerning commercial vehicles, to study the correlation between pass-by and stationary noises through measurements executed according to external noise standards. We consider two sets of experimental data: before the new legislation (higher levels) and lower levels satisfying the new limits in Brazil. In addition we calculate the Loudness in sones, from the octave band spectrum, and compare the results with the usual evaluation in dB(A), with the purpose of emphasizing the qualification besides the quantification aspects and promoting conditions for people understanding. We have applied Brazilian standards which are technically equivalent to their correspondent ISO 362 and ISO 5130. Some points regarding the application of these standard are in discussion since the last few years, as follows: The application of ISO 5130 in circulation vehicles and its correlation and meaning when compared to pass-by noise.

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).

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”.

This article has as objective the demonstration of a methodology to create component test rigs using numerical simulation techniques (FEM - Finite Element Modelling) as an aiding tool. It also emphasises the interaction between modern design procedures and experimental testing, regarding their consequences to product development. The case study was the development of a prototype chassis components durability test rig. The target was to reproduce a failure occurring at a crossbeam subframe on the assembly with the leaf spring mounting in order to test possible proposed solutions. An initial rig concept was created using experimental data. This conception failed to reproduce the crack at the point where it occurred in the prototype. A new rig was virtually designed and simulated. As the simulation showed proper results, it encouraged the construction of this new rig, which reproduced the failure as expected.

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).

The paper presents the concepts and applications regarding Articulation Index (AI) that is widely used in the automotive industry as a powerful parameter to qualify/quantify the middle and high frequency spectra associated to the internal noise of vehicles. We are able to show a short historical review including the today used definitions and calculations based in third octave band spectra through and idealized speech region model like our pioneer Brazilian standard. We show also other applications, where AI can be an excellent tool to evaluate vehicle acoustics. We emphasize the relation of AI to Speech Intelligibility and make considerations concerning other factors influencing Intelligibility. In addition we comment the integration we have produced with an overall noise parameter like dB(A) - (H-index) and the proposition of an AIM - Articulation Index Modified.