Schwartz, Jeffery, Schwaab, Mack, Blumenthal & Koch
Device for judging knocking strength
 A device for judging knocking strength of an engine has a sensor (1) which detects pressure variations in a combustion chamber of the engine. A rectification circuit (3) rectifies the output of the sensor (1), the output of the rectification circuit (3) being smoothed by a smoothing circuit (4) to give the envelope waveform of the output of the sensor (1). The envelope waveform is differentiated by a differentiating circuit (5), the amplitude of the output of the differentiating circuit (5) being used to detect the knocking condition. 
Nissan Motor Co., Ltd.
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additional additional inventional inventional
Kenichi
Yoshida