Steven P Kuritz

US Patent:

55919006, Jan 7, 1997

Filed:

Sep 23, 1994

Appl. No.:

8/311607

Inventors:

Steven P. Kuritz - Los Angeles CA
Brian K. Blackburn - Rochester MI
Scott B. Gentry - Romeo MI
Joseph F. Mazur - Washington MI

Assignee:

TRW Vehicle Safety Systems Inc. - Lyndhurst OH
TRW Inc. - Lyndhurst OH

International Classification:

G01M 300
G01F 1500
B60R 2116
B60R 2126

US Classification:

73 52

Abstract:

An apparatus (20) for sensing pressure in a stiff wall sealed vessel (30) comprises a piezoelectric transducer (200) operatively coupled to the vessel (30) for transferring energy to pressurized fluid in the vessel (30). A piezoelectric sensor (202) is operatively coupled to the vessel (30) for providing a received electrical signal having a frequency value indicative of the oscillation frequency of the pressurized fluid. A receiver circuit (224, 226, 228) is operatively connected to the sensor (202) and provides a fluid resonating signal having a frequency indicative of the fluid pressure in the vessel (30). A drive circuit (230) is operatively connected to the receiver circuit (224, 226, 228) and to the piezoelectric transducer (200). The drive circuit (230) initially drives the piezoelectric transducer (206) with noise. Subsequently, the drive circuit (230) drives the piezoelectric transducer (200) with an energy wave having a frequency equal to a frequency value functionally related to the natural frequency of the pressurized fluid in the vessel (30).