Integrated ID-system for sensors used in engine development

Country:
Austria

Client:
AVL-List GmbH

Background:
AVL-List GmbH is a worldwide renowned leading developer of motors and measurement systems. Shorter development times and a growing diversity of automotive vehicles require increased application efforts in motor development. One standard tool in the development process of combustion engines is to measure the pressure in the cylinder. Motors are equipped with a range of different pressure sensors during development and testing, each of which has different sensor characteristics. Consequently, each sensor had to be connected to the reading unit and parameterised most carefully, a working step that inevitably is a (potential) source of error that increases significantly with the number of sensors and motors. Falsely parameterised sensors give wrong results and lengthen the time necessary on the test stand.

CTR services:
The aim of the cooperation between CTR and AVL is to develop a method to give each sensor its own, unique identification (ID) tag. Under the conditions for applications in a combustion engine, the ID tags had to be able to withstand high temperatures, up to about 400 °C, and be small enough to be inserted into the existing sensor geometry. The solution for this demanding problem has found by using a passive, wireless surface acoustic wave (SAW) element. This piezoelectric component has an individual code in form of reflectors deposited onto the surface. When a high-frequency reading pulse is sent into the SAW tag, a time-delayed response signal is emitted back that contains the information of the reflector array and hence the code. Using such a system, each sensor can be identified individually and matched to its calibration data, thus effectively excluding the possibility of measurement errors due to parameter mismatch. Additionally, this ID system allows reaching a higher level of automation and opens new possibilities for flexible system development.

Project duration:
2,5 years 

Project scope:
Technology monitoring; design of SAW elements; coding of ID tags; investigation into the long-time stability; customer support during tag integration into the sensor; development of a customer specific reader module with application-specific software; integration into AVL measurement system; technical support in transfer to series production