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Due to its more and more widespread diffusion, Air Conditioning (A/C) systems in automobiles will face two main challenges in the near future: to improve the evaluation and control of perceived thermal comfort, and to reduce the fuel consumption increase due to its use (up to 70% in urban operation under hot weather [1]). In view of future regulations and heightening environmental concern, rapid action is needed to reduce such negative A/C impact. Moreover, the A/C system has also an important role in safety, since it has to assure the driver’s visibility by avoiding fogging formation on the windshield in any condition of use. This function has to be assured in the most reliable and automatic way, minimising the interaction of the driver with the A/C system itself. The two research projects described in the present paper have the following goals: • To improve the perceived thermal comfort evaluation. • To lower the impact of air conditioning system on fuel consumption. • To detect incipient fogging conditions in a reliable and predictive way. The research activity has been performed with the following constraints: • To minimize the number of sensors. • To reduce the cost of the air conditioning system.

The monitoring of several vehicle and engine operation parameters has been a key factor for the successful introduction of electronic control of the most important car performances. Among the several measured quantities, the measurement of fluid mass flow still requires sophisticated and expensive transducers, no convenient and low cost technologies having been available so far. The recent invention of the concept of bi-layer ribbons, has allowed to adjust the sensitivity of magneto-elastic sensing elements to be employed in the construction of bending sensors, in order to match their metrological properties to the wanted application. Due to their low production cost, small size and good reliability, magneto-elastic bi-layer sensors proved to be a promising technology for the large scale production of fluid flowmeters, which can be used in the automotive industry and are operated in a very wide temperature range, with temperatures spanning from −25 to 115 °C. In the present research, two main application domains have been taken into consideration namely the flow metering of the air streaming into engine air intake manifolds and the measurement of the flow rates of refrigerant fluid in the cooling loop of car air conditioning systems (HVAC). The technical feasibility of agglutinated bi-layer flow sensors, has been investigated and evaluated, by means of experimental testing under real like operating conditions. The present paper briefly describes the manufacturing process and the experimental methodologies. Preliminary results are given and future developments are foreseen, while further research guidelines are established.