A method to reduce the frequency of knock misjudgment

Abstract

The invention discloses a method for reducing the frequency of misjudgment of knocking, which comprises the following steps: installing y-axis and x-axis acceleration sensors on the engine to collect vibration signals Vy and Vx in the y-axis and x-axis directions; Processing: preset knocking time range t1~t2, obtain vibration signals Vyt and Vxt in the y-axis and x-axis directions within t1~t2; set center frequencies f1, f2, preset knocking frequency ranges f1±nf1 and f2±mf2, Let the knocking frequency be Vyt in f1±nf1 and Vxt in f2±mf2, and obtain the vibration signal Vyf in the y-axis direction in f1±nf1 and the vibration signal Vxf in the x-axis direction in f2±mf2, n∈(0,1) , m ∈ (0, 1); integrate Vyf and Vxf with f1 and f2 to obtain integral values ​​Ky1, Ky2 and Kx1, Kx2; weight each integral value to obtain knock intensity values ​​Ky and Kx; set knock thresholds A and B, if Ky exceeds A and Kx exceeds B, it is judged that knocking has occurred, otherwise it is judged that it has not occurred. The invention can reduce the occurrence frequency of knocking misjudgment and realize the judgment of engine knocking.

Description

technical field [0001] The invention belongs to the technical field of automobile engine control, and in particular relates to a method for reducing the frequency of misjudgment of knocking. Background technique [0002] At present, engine knock control generally uses a single-axis acceleration sensor to collect the knock signal in a certain direction of the engine cylinder. After the signal is processed, the signal is integrated through a preset knock center frequency and knock window. After processing, the knock intensity value is obtained. [0003] In the prior art, if the knock intensity value exceeds the knock threshold, engine control is triggered to eliminate knock by annealing the ignition angle. Knock signals are often interfered by other vibration signals, and the interference signals mainly come from moving parts during engine operation: including valve timing mechanism, fuel injector, crank connecting rod mechanism and piston. The design, processing and assembl...

AI Technical Summary

Problems solved by technology

However, the current technical solution has a common problem that the frequency of misjudgment of knocking is relatively high, causing frequent de-ignition angles of the engine, resulting in reduced power of the engine, increased fuel consumption, and worsened emissions.

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