Tutorials

Gianmarco Battista

Università Politecnica delle Marche, Italy

Automotive industry is always focused on the acoustic comfort of its products, ranging from utility vehicles to GT and Sport cars. On one hand, Internal Combustion Engine (ICE), are getting increasingly quieter, on the other hand, new challenges are rising with the diffusion of Electric Vehicles (EV). Moreover, the continuous improvement of internal noise in vehicle cabins requires more and more powerful techniques to reach target performance and improve the quality perceived by customers.

Single microphone measurements can only provide information about overall level or spectral content of the noise. Instead, acoustic source mapping with microphone array-based techniques can accomplish source localization, separation of contributions and quick troubleshooting. Given the huge number of techniques, variants and possible classifications, it could be tricky for a newbie user to pick up the best method for a particular application. The knowledge of the basic concepts about different array designs and acoustic mapping techniques enables the user to choose the best combination for each use case.

A general overview of acoustic mapping methods will clear up the ideas about pros and cons of beamforming algorithms, deconvolution techniques and inverse methods. Also, general guidelines about the choice of suitable microphone array layout will be provided. Practical examples will show the whole source mapping process and the effect of the most influencing parameters in the application of these powerful measurement techniques.

Alessandro Germak

National Institute of Metrological Research (INRiM), Italy

In automotive industry, metrology is involved in all measurements required for the development of a new model, for the performance verification, for safety and during the normal road use when the electronic control units (ECUs) have to manage a variety of measurements coming from the on-board sensors.

Temperature, Speed, Pressure, Frequency, Length, Time, Tension, etc., are examples of the several quantities measured by different sensors that instantaneously must be analysed for providing appropriate instructions to the actuators for the correct operation of the vehicle and, even more important, for providing useful information to the driver for safe driving; it is therefore very important that ECUs and drivers can take correct decisions based on accurate and reliable measurements.

For such purpose, a correct metrological traceability must be ensured: condition required as a basis by the quality standards for proper management of measurements. The traceability, defined as property of a measurement result whereby the result can be related to a reference through a documented unbroken chain of calibrations, each contributing to the measurement uncertainty, links the measurement provided by the measuring instrument to the International System of Units.

For such purpose, a correct metrological traceability must be ensured: condition required as a basis by the quality standards for proper management of measurements. The traceability, defined as property of a measurement result whereby the result can be related to a reference through a documented unbroken chain of calibrations, each contributing to the measurement uncertainty, links the measurement provided by the measuring instrument to the International System of Units.

Alessandro Germak, first technologist at the National Institute of Metrological Research (INRiM) where he has been carrying out research for over thirty years, is responsible for the primary force and hardness national standards and for the primary method for measuring local acceleration of gravity. He is a technical expert for the accreditation bodies for calibration laboratories and member of the international Technical/Consultative Committees and Working Groups (CIPM, EURAMET) for the quantities of interest. Since twenty years, he is adjunct professor at Polytechnic of Torino for Experimental Statistics and Mechanical Measurements course.

Luca Romagnuolo

University of Naples Federico II - Department of Industrial Engineering

Unburned hydrocarbon evaporation from gasoline vehicle fuel tanks has long been recognized as an important source of pollution. VOCs, that evaporate from gasoline, are very dangerous for both human health and environment. Therefore, international regulations on evaporative emissions are becoming increasingly stringent every year. To deal with these regulations, all modern gasoline vehicles are equipped with an EVAP system, which commonly consists of a carbon canister filter, which stores gasoline vapors that later will be purged by the engine intake manifold and burnt inside the engine cylinder along with the fresh charge.

Unburned hydrocarbon evaporation from gasoline vehicle fuel tanks has long been recognized as an important source of pollution. VOCs, that evaporate from gasoline, are very dangerous for both human health and environment. Therefore, international regulations on evaporative emissions are becoming increasingly stringent every year. To deal with these regulations, all modern gasoline vehicles are equipped with an EVAP system, which commonly consists of a carbon canister filter, which stores gasoline vapors that later will be purged by the engine intake manifold and burnt inside the engine cylinder along with the fresh charge.

A general overview of techniques adopted to study evaporation from gasoline tanks will be provided, with particular attention to the use of a Sealed Housing for Evaporative Determinations. Furthermore, an in-depth analysis of the canister adsorption and desorption behavior will be illustrated, along with useful indirect techniques adopted for analyzing the canister loading and purging phases.