US 6,185,984 B1Granted

Device for detecting the knocking of an internal combustion engine

AssigneeMitsubishi Denki Kabushiki Kaisha

InventorYasuhiro Takahashi

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Abstract

A device for detecting the knocking of an internal combustion engine maintaining a favorable knock-detecting state even when a noise component having a small amplitude and lasting long is superposed on an ionic current detection signal. The device comprises a means 1 for detecting the ionic current i that flows through a spark plug 8, a filter 2 means for picking up knock signals Ki from the ionic current, a means 22 for judging the knocking state based on the knock signals, a means 11 for operating a first integrated value Km1 of the knock signals, a means 21 for setting a basic threshold value TH based on the first integrated value, a means 12 for operating a second integrated value Km2 by integrating only those knock signals having amplitudes larger than a lower-limit level among the knock signals, and a means 32 for setting the basic threshold value as the lower-limit level, wherein the occurrence of knocking is judged based on the second integrated value.

Claims7

Dependent claims

A device for detecting the knocking of an internal combustion engine, comprising:

an ionic current detecting means for detecting the ionic current that flows through a spark plug during the combustion in an internal combustion engine;
a filter means for picking up knock signals from said ionic current;
and
a knock judging means for judging the knocking state of said internal combustion engine based on said knock signals;
said device for detecting the knocking of an internal combustion engine further comprising:
a first integrating means for operating a first integrated value by integrating said knock signals;
a threshold value-setting means for setting a basic threshold value based on said first integrated value;
a second integrating means for operating a second integrated value by integrating only those knock signals having amplitudes larger than a lower-limit level among said knock signals;
and
a lower-limit level-setting means for setting said basic threshold value as said lower-limit level;
wherein said knock judging means judges the occurrence of knocking based on said second integrated value.

8 more elements

Dependencies are inferred from the claim text.