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Aiming at evaluating the effects of natural gas composition on engine operation, the Engine Group of IPT has completed a series of dynamometer tests in a Mercedes Benz M366G gas engine. Twenty-five gaseous fuel compositions, several specially prepared to extend the available CNG compositions, were engine tested. The tests were executed to evaluate performance, exhaust emissions and knock-limited spark timing. The experimental results were correlated with methane and Wobbe numbers calculated from the gas composition. The obtained data corroborate the relevance of these parameters to engine operation. For the tested engine, that uses an open loop fuel system, the data indicate the need to maintain the natural gas specifications in narrow limits if one wants to explore the natural gas low pollutant potential. This study has subsidized the elaboration of a Brazilian vehicular natural gas specification.

Today almost any engine research and development work, looking for an optimal design, performance improvement or emission reduction, demands the combustion monitoring. The simplest way to do so is by measuring the cylinder pressure, as function of piston movement or of time. This paper describes the development of a high-pressure data acquisition system that provides the basis to a flexible and powerful combustion analysis tool for engines. Similar equipment available in the market usually has embedded software, making it difficult to adapt to an unusual R&D scenario. Comparing the data gathered by the system with data collected by others means, it was possible to determine its accuracy.

Since the early 90's several studies using remote sensing equipment for on-road vehicle emission measurement, more commonly denominated remote sensing device (RSD), have been presented. They show different RSD technical solutions and application methods, fact that indicates a solid evolutionary process. This paper makes an analysis of this equipment and its applications, presenting and discussing its operational principles and results, considering a diverse automotive technological scenario as the Brazilian one.