Search Results

Several electronic control systems will be introduced into our cars in the near future, thus leading to an increasing demand for new and more sophysticated sensors. The sensor structure could be drastically changed because more and more functions will be required to the central microprocessors of the electronic control units, causing their overload. Taking into account that a considerable amount of microprocessor time and memory is spent for the collection and the elaboration of sensors signal, it makes sens to relieve them displacing a part of the electronics onto the sensors thus obtaining upgraded and easily usable signals. This process will lead at first to integrated sensors and later to smart and eventually microprocessor based sensors. In the paper an attempt will be given to forsee how the systems structure, the sensors configuration and the relevant implementation technologies should evolve to fulfil the future requirements of car electronics.

The evolution of the agricultural mechanization has transformed the tractor from a simple tractive device into a more sophisticated machine to be matched with a wide variety of specific implements. The part allowing the control of the implement position and therefore its proper operation is the hitch lifting system. To increase the accuracy and the functionality of this system, up to now hydraulically or mechanically driven, and to reduce also the installation, adjustment and operating problems an electronically controlled system has been developed. The electronic system is based on a microprocessor unit which either provides to elaborate the signals supplied by suitable position and tractive force sensors and to fulfil, on the base of pre-set strategies, the operator requirements by means of proper actuators. Moreover the electronic unit can, at the same time, display to the operator the working parameter of the implement.

More and more sophysticated electronic controls are going to be installed on cars, industrial vehicles and other means of transport, whose performances strictly depend on the accuracy and reliability of the sensors used to detect the operating conditions of the vehicle they shall manage. In particular as far as the pressure sensors concerns, the introduction of the monolithic devices (based either on silicon and on ceramic) has practically solved the problems of the pressure measurements at the intake manifold of the engine needed for the ignition and fuel injection systems. These pressures are usually ranging between 0 and 2 bar. However brakes and gear box electronic controls require sensors for much higher pressures (up to 50 bar for the gear box) and much more severe environmental conditions.

Taking advantage of thick film resistors piezoresistive properties, a certain number of pressure sensors has been developed for automotive applications. The main applications are related to manifold pressure measurements in ignition and injection electronic systems for conventional and turbocharged engines, in oil and air monitoring systems for cars and heavy trucks, in diagnosis benches. The new developed sensors fulfil the requirements for low cost, high performances and high reliability necessary in today automotive electronic control systems. On the other side they can also successfully replace the mechanical and conventional pressure sensors (i.e. LVDT, potentiometric) already used in the above mentioned applications.