Control devices for internal combustion engines

Abstract

A control device of an internal combustion engine includes a filter processing portion which performs a filter processing on the vibration level extracted by the vibration level extraction portion, and calculates a vibration level after the filter processing; and an abnormal ignition suppression control portion which compares the vibration level after the filter processing to the abnormal ignition determination value when a retard correction equal to or greater than a predetermined value is performed by the knock control portion, in a case where it is determined that the vibration level after the filter processing is equal to or greater than the abnormal ignition determination value, determines that the abnormal ignition is generated in the internal combustion engine, corrects and controls the combustion control portion in a direction of suppressing the abnormal ignition.

Description

technical field [0001] The present invention relates to a control device for an internal combustion engine, and more specifically, to a control device for an internal combustion engine capable of distinguishing abnormal combustion occurring in the internal combustion engine into abnormal ignition such as deflagration and pre-ignition, post-ignition, etc. To be detected to carry out control suitable for various abnormal combustion. Background technique [0002] It is known that, generally during the operation of an internal combustion engine, when deflagration, which is a kind of abnormal combustion of the internal combustion engine, occurs, vibrations of a fixed frequency band will occur in the internal combustion engine according to the structure of the internal combustion engine and the vibration mode of the deflagration. A method using a vibration sensor to detect A control device for an internal combustion engine that controls the internal combustion engine based on the ...

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Problems solved by technology

[0017] However, in the determination method described in Patent Document 3, which determines the occurrence of abnormal ignition based on the time difference between the ignition timing and the vibration occurrence time, it is difficult to determine the vibration occurrence time due to abnormal ignition because the internal combustion engine in operation is always vibrating. , even if the relatively large vibration start position and peak position are detected as the vibration occurrence time, the deviation of these positions is large, and there are cases where normal deflagration is misjudged as abnormal ignition, and the detection of abnormal ignition may be missed

[0018] In addition, Patent Document 3 discloses a method of judging that it is pre-ignition when the vibration increases despite retarding the ignition timing. Cases where strong vibrations diverge, and cases where strong vibration levels are generated at the beginning and increase and decrease, therefore, detection omission of abnormal ignition occurs even if this disclosed method is used

[0019] In addition, when the above-mentioned method of judging the occurrence of abnormal ignition when no abnormal vibration above a predetermined level is detected continues for a time interval shorter than the predetermined interval described in Patent Document 4, there is the following technical problem: even if there is a vibration level that greatly exceeds the specified Level abnormal vibration occurs, and it cannot be detected when such abnormal vibration occurs continuously at an interval slightly longer than the specified interval.

In addition, Patent Document 4 also discloses a method of calculating the cumulative value of the occurrence frequency of abnormal vibrations and judging that it is pre-ignition when the cumulative value is equal to or greater than the pre-ignition judgment value, but there is the following problem: In the case of using fuel with a low octane number, strong vibrations will occur at a high frequency even in the knocking generated during acceleration, etc., until the ignition delay correction is fully completed. Therefore, when using only this In the case of high frequency, deflagration may be misjudged as abnormal ignition

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