The invention discloses an engine knock detection method. A knock recognition window of a current
combustion cylinder and the
crankshaft phase position of the closing time period of an air
inlet valve of a next
combustion cylinder are compared, whether the closing
noise of the air
inlet valve enters the knock recognition window of the current
combustion cylinder or not is judged, if the closing
noise of the air
inlet valve enters the knock recognition window of the current combustion cylinder, when the knock recognition window of the current combustion cylinder comes, the overlapping knock strength Cvirkr of the current combustion cylinder is calculated through the default
background noise Srkr, Cvirkr=ikr / Srkr, ikr is a knock sensor
signal integration variable of the knock recognition window of the current combustion cylinder, and because the default
background noise is larger than the knock sensor
signal integration variable of the knock recognition window of an internal combustion cylinder under the normal condition, and a knock
detection threshold is improved, the engine knock misjudgment caused when the closing
noise of the air inlet valve enters the knock recognition window of the current combustion cylinder can be reduced. The invention further discloses an engine pre-ignition detection method.