Patent Number: 7,709,998

Title: Measurement system for measuring cylinder pressure in an internal combustion engine

Abstract: A plurality of exchangeable, different piezoelectric pressure sensors (4) comprise integrated SAW elements (60) as identification units whose identification data can be read by an interrogation unit (3) via a common connection cable (61). The analysis unit (2) for the measurement signals and the interrogation unit (3) for the identification data can be connected by a common coupling unit (5) to the connection cable (61). The coupling unit (5) has a coupling capacity (6) which connects with high frequency the interrogation unit (3) to the signal line of the connection cable (61), as well as a coupling inductance (7) which connects with low frequency the load amplifier (1) of the analysis unit (2) to the connection cable (61), thus neatly separating the useful signal from the identification signal and keeping a high-impedance measurement chain from the sensor (4) to the input of the load amplifier (1). An SFSCW radar can further be used to improve interrogation of the identification data.

Inventors: Stelzer; Andreas (Linz, AT), Hauser; Robert (Bodensdorf, AT), Schuster; Stefan (Linz, AT), Scheiblhofer; Stefan (Linz, AT), Leitmeier; Klaus (Graz, AT)

Assignee: AVL List GmbH

International Classification: H01L 41/107 (20060101)

Expiration Date: 5/04/12018