Abstract: A knock sensor for which a fabrication process is simple and moreover which can detect up to a high-frequency region is provided. A sensing element 11 composed of a semiconductor the weight (mass) thereof being 1 g or less and a signal processing circuit 11 are mounted on a fixing pedestal 9. The fixing pedestal 9 is fixed to a connector 2 side by means of adhesive or the like. Additionally, the connector 2 is fixed by means of caulking 16 of a housing 1. As a result thereof, the sensing element 11 is disposed within a space formed by the fixing pedestal 9 and the housing 1.

Abstract: A memory stores and holds both the number of crankshaft angle pulse signals occurring after detecting a reference portion when an engine stops and data relating to whether the reference portion which is supposed to be next detected upon re-start of the engine is a reference position of the camshaft. When the engine is re-started, it is determined whether a reverse rotation of the crankshaft across the reference position happened by comparing a predetermined value with the total obtained by adding the number of pulse signals stored in the memory and the number of pulse signals occurring until the reference portion is first detected again. When such reverse rotation happened, the reference position of the camshaft is shifted by 360.degree. CA. Therefore, regardless of whether such reverse rotation across the reference position happened or not, the engine timing cycle is again precisely synchronized.

Abstract: A knock sensing apparatus for an internal combustion engine which can detect a failure in a knock sensor signal system correctly even when a changeover operation due to hardware is performed at a place between a knock sensor and a band pass filter. In this knock sensing apparatus, the failure detection by a failure detecting circuit for detecting a failure in a signal system from knock sensors is invalidated for a predetermined period after one of the knock sensors has been changed over to the other knock sensor, or one of two kinds of pass bands of a band pass filter has been changed over to the other pass band, to prevent a decrease in failure detection accuracy due to the signal delaying action of the switched capacitor filter.

Abstract: A knocking vibration detecting unit (1) and a knock deciding unit (c) are integrated, and the communications of a knock intensity between the knock deciding unit (c) and an engine controlling microcomputer (7) are carried out in combination of a change from the previous value of a signal line level. In the engine controlling microcomputer (7), the ignition timing is controlled by a predetermined retard angle in case of combination of no change of the present read signal line level from the previous signal line level.Thus, an internal combustion engine is prevented from any damage by relieving a failure without fail when a signal line (10) is troubled, while minimizing the influences of noises and reducing the space and size of an ECU.

Abstract: A knocking control system for an internal combustion engine which is capable of surely detecting and reducing the knock of the engine. The knocking control system is equipped with a logarithmic conversion section for performing the logarithmic conversion of the effective knock intensity of the output signals of a knock sensor and a central value detecting section for detecting a central value in the logarithmic conversion value distribution. The deviation between the central value and the logarithmic conversion value is averaged to obtain an average value corresponding to the standard deviation of the logarithmic conversion value, thereby producing a knock decision level on the basis of the average value. The knock decision level is compared with the logarithmic conversion value so that the occurence of the knock is determined in accordance with the comparison result and the ignition timing of the engine is controlled in accordance with the determination result so as to reduce the knocking state.