초록 ▼

This invention provides a system and method for detecting misfires of an engine that reduces on board computer memory loss and shortens the time to process routines to detect misfires. Teeth are installed in a flywheel connected to a crank shaft, and analog signals that are generated by a difference

This invention provides a system and method for detecting misfires of an engine that reduces on board computer memory loss and shortens the time to process routines to detect misfires. Teeth are installed in a flywheel connected to a crank shaft, and analog signals that are generated by a difference between a tooth and a bottom of a tooth space are detected by a magnetic pickup. The analog signals are transformed into digital signals by a digital circuit, and the number of HIGH values of the digital signals and time between the top dead centers (TDCs) are detected by a timer and counter. An angular acceleration of the flywheel is then found by an electric control unit (ECU). A magnitude of frequency components of the angular acceleration is found performing a discrete Fourier transform (DFT) on the angular acceleration with respect to a Walsh function as a basis function, and the magnitude of the frequency components are compared with a predetermined reference value to detect a misfire of the engine. When the comparison result exceeds the reference value, an engine misfire is deemed to have occurred.

대표청구항 ▼

1. A system for detecting a misfire of an engine, comprising:a flywheel connected to a crank shaft and having teeth; a magnetic pickup generating analog signals according to variations of a magnetic field caused by a difference of a distance between a tooth and a bottom of a tooth space on the flywh

1. A system for detecting a misfire of an engine, comprising:a flywheel connected to a crank shaft and having teeth; a magnetic pickup generating analog signals according to variations of a magnetic field caused by a difference of a distance between a tooth and a bottom of a tooth space on the flywheel; a switching circuit receiving the analog signals and outputting digital signals; a timer and counter detecting a period of the digital signals and a number of HIGH values; an electric control unit (ECU) receiving the period of the digital signals and the number of the HIGH values to detect the misfires of the engine, wherein the ECU receives the period of the digital signals and the number of the HIGH values detected from the timer and counter, and finds an angular acceleration of the flywheel, and performs frequency analysis on the angular acceleration based on a Walsh function as a basis function so as to find a magnitude of an amplitude of frequency components, and compares the magnitude of the amplitude with a predetermined reference value so as to determine an occurrence of a misfire.