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Emerald Group Publishing Limited
Copyright © 2004, Emerald Group Publishing Limited
Automotive and aerospace applications
Automotive and aerospace applications
Keywords: Sensors, Automotive, Aerospace
At present, technical and technological innovation has progressed at such an accelerated pace that it has permeated almost every field of our life. This is especially true in the field of cars. In the early 1970s, people were dreaming about electrically driven cars – the reasons were the first realization of the lack of fuel sources as well as environmental pollution. However, the success of hybrid electric vehicles with fuel-cell power sources is still limited even today. On the other hand, with almost continual technological innovations driving automotive electronics, the vision of an electronically controlled car driven with conventional engines became a reality in the 1990s. The basis of this development was the widespread availability of low cost sensors and actuators that enabled the control of a great number of engine functions. At present, a new vision is in sight: the idea of intelligent cars – based on microsystems. The trends in the development of microsensors for automotive applications address the emerging need for increased safety, increased comfort, and reduced power consumption.
A car normally contains about 30 electrical/ electronic system with more than 100 sensors – this is a level comparable with aerospace applications in airplanes and space shuttles. The cost value of electronic components within a car could be estimated to be in the order of 20 percent of the total cost. In this context, particularly micro-sensors will play a major contributory role in the car of the future.
Engine optimisation is achieved through the use of pressure sensors, flow sensors, temperature sensors and rotary position sensors which are parts of the engine control systems and provide data on the engine parameters to the driver. Accelerometers have been used for many years in airbag safety systems. These applications continue to grow with new developments of yaw rate and roll-over sensors that will provide even higher safety levels. Oil level and quality as well as tyre pressure monitoring sensors are also available. Additionally, new systems such as global positioning systems (GPS) and heating, ventilation, air conditioning (HVAC) for car safety and driver comfort systems are currently penetrating the market. Obstacle detection is a prerequisite for a variety of innovative safety and driver assistance system, like cruise control, collision avoidance, anticipatory crash sensing, and occupant position recognition or night vision. As foreseen, radar and optical detection will form part of the next generation of safety systems. Chemical sensors have also found widespread application in cars, like lambda sensors in exhaust systems for optimizing air/fuel ratio and CO/NOX gas multi-sensors for controlling the passenger compartment atmosphere. All the success in car electronics is due to the availability of low sensor devices.
The main areas for sensor implementation in the aerospace sector include civil and fighter aircrafts, helicopters, missiles, avionics and flight control. The sections and systems in an aircraft within which sensors and microsystems are used are as follows: navigation and attitude, man machine interfaces, navigation, engine and reactors, energy management, structure monitoring, landing systems, mission electronics. Cost issues here are not as tight as in automotive applications.
What are then the requirement characteristics for both application areas? The two keywords are very obvious: accuracy and reliability. Accuracy and reliability, since the malfunction of the systems can cause catastrophes. And a level of accuracy and reliability, which cannot be reached by pure sensor devices – for this intelligent integrated microsystems are required.
Gábor HarsányiDepartment of Electronics Technology, Budapest University of Technology and Economics, Budapest, Hungary.