Engine Knock Detection Method and Engine Preignition Detection Method

Abstract

The invention discloses an engine detonation detection method. A crankshaft phase of a detonation identification window of a current combustion cylinder is compared with a crankshaft phase of an oil-fuel injector needle-valve seating period of a next combustion cylinder; whether oil-fuel injector seating noise enters the detonation identification window of the current combustion cylinder is determined; if so, an overlapping detonation intensity Cvirkr of the current combustion cylinder is calculated by using default background noise Srkr before the detonation identification window of the current combustion cylinder comes, wherein the Cvirkr is equal to ikr / Srkr and the ikr expresses a detonation sensor signal integration value of the detonation identification window of the current combustion cylinder; and bercause the default background noise is larger than a detonation sensor signal integration value of a detonation identification window of an internal combustion cylinder normally and a detonation detection threshold value increases, erroneous engine detonation judgement caused by entrance of the oil-fuel injector seating noise into the detonation identification window of the current combustion cylinder can be reduced. In addition, the invention also discloses a preignition detection method of an engine.

Description

technical field [0001] The invention relates to engine control technology, in particular to an engine knock detection method and an engine pre-ignition detection method. Background technique [0002] The knock sensor is an acceleration sensor that can detect the vibration and sound waves of objects. If the engine has abnormal knock combustion or early combustion, the vibration and sound waves will be detected by the knock sensor and converted into electrical signals and input to the electronic control unit. When the electronic control unit detects the occurrence of knocking combustion, the electronic control unit will adjust the ignition to avoid the occurrence of continuous knocking combustion; Measures such as restricting the throttle valve protect the engine. Usually, a knock sensor is installed on the 4-cylinder in-line engine, which monitors the combustion of the engine in the corresponding detection window, and determines which cylinder has knock combustion or pre-ign...

AI Technical Summary

Problems solved by technology

However, studies have shown that the center frequency band of the injector needle valve seating (injector closing pulse) noise is very close to the center frequency band of the vibration generated by knocking combustion, and the noise interference cannot be eliminated by the existing band-pass filter function

If the noise of a certain fuel injector needle valve seating (the closing pulse of the fuel injector) enters the knock detection window, the existing electronic control unit cannot distinguish whether the signal of the knock sensor at this time is the fuel injector needle valve seating (fuel injection The knocking signal is still present in the noise of the closing pulse of the fuel injector, and the electronic control unit will also regard the noise of the needle valve seat of the injector (closing pulse of the fuel injector) as a knocking signal, resulting in continuous misidentification of knocking, which may Leading to continuous ignition angle delay, resulting in high exhaust temperature, high fuel consumption, poor power, large torque fluctuations and other problems

Similarly, if the noise of a certain fuel injector needle valve seating (injector closing pulse) enters the pre-ignition identification window, the existing electronic control unit cannot distinguish whether the knock sensor signal at this time is the fuel injector needle valve seating (injector Injector shut-off pulse) noise still appears pre-ignition, the electronic control unit will mistakenly detect the noise of injector needle valve seating (injector close pulse) as a pre-ignition signal, which may cause the engine to adopt fuel cut-off, enriched mixture Measures such as reducing gas and restricting the throttle valve will have a serious negative effect on the performance of the engine and the drivability of the vehicle

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