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Technical Paper

Using SIL/PSIL to estimate Speech Intelligibility in Vehicles

2005-11-22
2005-01-3973
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.
Technical Paper

Some Considerations Regarding the Development Procedure of Commercial Vehicles Shifting Systems

2003-11-18
2003-01-3582
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.
Technical Paper

“IQDP: The Challenge of the Development Area to Evaluate its Suppliers”

2001-03-05
2001-01-3975
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.
Technical Paper

New Procedure for Signal Compression in Test Benches

2001-03-05
2001-01-3796
This paper discusses some aspects of durability tests in laboratory, justifying the necessity of a new procedure for data compression. Attention is paid to dynamic tests, with the presence of inertia forces. The new procedure is introduced, which uses concepts of fatigue due to vibration and signal analysis. The compression procedure is applied to generate a synthetic signal for the experimental stress test of an automotive component.
Technical Paper

Development of a Test Bench for Static and Dynamic Tests of a Spring Leaf for the Suspension of Commercial Vehicles

1999-12-01
1999-01-2990
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.
Technical Paper

“IQTC: A Practical and Unified Index for the Evaluation and Continuous Improvement of Suppliers”

1999-12-01
1999-01-2989
Considering that the opening of the national market varies at the mercy of the economy and the government, Mercedes-Benz do Brasil launched a program to support the local suppliers. Within this program, one may enhance the tool IQTC (Commercial and Technical Qualitative Index). One deals with an index that will enable the supplier to exactly know in which scores he is “weak”, where he is strong and where he has to improve. The transparency regarding the information has to be complete. The general composition of the index will be presented with its criteria and requisites in which the various areas of Mercedes-Benz participate in, with additional details for the IQDP (Quality Index in Product Development), that is the subindex prepared by the Development area. Some practical results involving the evaluation of suppliers will also be shown, whose results, however, will not be nominally quoted.
Technical Paper

Illumination and Signalling Devices: Functional and Durability Tests

2004-11-16
2004-01-3255
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).
Technical Paper

Test of Telematics System during the “9o Rally Internacional dos Sertões”

2002-11-19
2002-01-3435
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”.
Technical Paper

New Policy of Durability Tests for Commercial Vehicles through Development of Low Cost Road Simulators

2002-11-19
2002-01-3385
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.
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