Gm Global Technolgoy Operations, Inc.

Douglas A Feldmaier

James A Hamburg

Robert Hickling

Francis Hap-Kwong Chen

Jing-yau Chung

A crash sensing and occupant restraint activating apparatus is disclosed for a vehicle having a welded unit body structure including a side rail extending back from the front of the vehicle on each side. An acoustic sensor near the front of each side rail generates a signal in response to acoustic vibrations due to metal deformation in a frontal crash. The signals from the sensors are processed through a bandpass filter and an envelope detector. A comparator/timer generates a crash signal to activate an occupant restraint only when the envelope of the filtered sensor signal exceeds a predetermined amplitude reference for a predetermined time period of substantially 5 milliseconds. The envelope detector has a time constant of substantially 2 milliseconds; and the bandpass filter passes 200 to 300 KHz.

Acoustic emission automotive crash sensor

A spark ignited internal combustion engine includes knock sensing apparatus comprising vibration sensing apparatus having a portion mounted on an engine component for vibration therewith and a tuned response to vibrations of a plurality of the acoustic cavity resonance frequencies of the engine cylinders. A separate signal processing channel is provided for the sensor output at each of the frequencies to indicate significant vibrations at the respective frequency. Coincidence means fed by all channels produce an engine knock signal only when significant vibrations are detected on all channels simultaneously.

Engine with knock sensing apparatus having multiple frequency tuning

The bulk temperature of the gas in a piston engine during combustion is determined by detecting the high frequency pressure oscillation in the combustion chamber operating the engine to produce knock and measuring the frequency of the lowest frequency mode of the high frequency knock signal. The frequency or inversely the period of that signal is a function of the gas temperature.

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Birmingham, MI, United States of America

Douglas A Feldmaier