Abstract: To obtain a knock control apparatus for internal-combustion engine having a function of judging whether or not the causes for failure have been solved for returning to normal knock control at the time of the solution, and capable of easily judging failure even in a failure mode in which it is difficult to raise the filter value and it is difficult to judge the failure.

Abstract: A device for detecting the knocking of an internal combustion engine, which maintains the background level at an optimum value irrespective of the knocking level, and features improved reliability by preventing the erroneous detection of noise or knocking when the knocking level is shifted. The device includes a counter 12 for operating signals N of the knocking level from the ionic current, an averaging circuit 13A for operating an average knocking level AVE, a circuit 14A for operating a background level BGLA by using an offset value, a comparator 15 for judging the knocking by comparing the signals of the knocking level with the background level, a circuit 16 for judging the average knocking level that lies in a predetermined region, and a circuit 17 for correcting the offset value depending on the result of judging the predetermined region, wherein the offset value is corrected toward a direction to cancel the increment or the decrement of the average knocking level depending on the predetermined region.

Abstract: To obtain a knock control apparatus for internal-combustion engine having a function of judging whether or not the causes for failure have been solved for returning to normal knock control at the time of the solution, and capable of easily judging failure even in a failure mode in which it is difficult to raise the filter value and it is difficult to judge the failure.

Abstract: A device for controlling knocking of an internal combustion engine featuring improved reliability by preventing signals of the knocking level from being erroneously detected as those of the noise level. The device detects an ionic current flowing through a spark plug, counts a signal of the knocking level from the ionic current, establishes an average knocking level from the signals of the knocking level and determines a background level from the average knocking level. A comparator judges the knocking state by comparing the signal of the knocking level with the background level. The device calculates the control quantity of the engine based on the operation conditions and the result of judgement of knocking. The device further judges a transient state and decreases the average knocking level depending upon a transience judgment signal in order to maintain a background level in a transient state at an optimum value.

Abstract: A knock control apparatus for suppressing knock event in an internal combustion engine by correcting a control quantity such as ignition timing for the engine while evading erroneous knock decision and erroneous knock control when a spark plug of the engine is in a sooting state.