Oblon, Fisher, Spivak, McClelland & Maier
Apparatus for detecting combustion timing
 An apparatus for detecting combustion timing in an internal combustion engine comprises: a microwave unit including a microwave oscillator for generating a microwave having a predetermined frequency, a transmission and reception separator for separating transmitted and received microwaves from each other, and a detector for detecting the received microwave so as to be converted to a low frequency signal; a probe including a microwave sensor for radiating the microwave from the separator into a combustion chamber and receiving a reflected wave, and a light sensor for electrically detecting light emitted upon combustion in the combustion chamber; and a processing unit including a peak detector circuit for detecting peaks of a microwave signal supplied by the detector, a luminous signal processor for detecting a peak value of a luminous signal supplied by the light sensor in each cycle and also detecting the time when the luminous signal reaches an intensity having a predetermined proportion to the peak value thereof, and an operating unit for operating a time difference between a middle point between a pair of peaks of the microwave signal and the time when the luminous signal reaches an intensity having a predetermined portion to the peak value thereof based on peak and luminous signals. The apparatus accurately detects the timing for starting combustion with respect to a top dead center of the internal combustion engine. 
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Teruo Kizo Yasuhiko Michiru
Yamanaka Hayakawa Suzuki Esaki