Misfire detection method by air-fuel ratio controller of internal combustion engine

Abstract

Abstract PURPOSE:To discriminate a misfire cylinder, display it and interrupt the fuel injection in that misfire cylinder by comparing the output pattern or compensated pattern of an air-fuel ratio detector with the stored misfire pattern condition such as a crank position. CONSTITUTION:The CPU inside a control unit 6 receives the detected signals from an air-fuel ratio sensor 5, an air flow meter 2, a crank angle sensor 3 and so on. When the fluctuations in r.p.m and the fluctuation in air flow rate are below the respective stored data, the CPU determines that the engine state is in the normal state. When the normal engine state is confirmed, the CPU reads the compensatory value of the air-fuel ratio (or the output value of the air-fuel ratio) for each cylinder. Next, the CPU calculates the average of the compensated air-fuel ratios of the cylinders and calculates an error between the detected air-fuel ratio in a cylinder and the average ratio. When this error is greater than the misfire reference error data stored in the ROM, the CPU determines that a misfire occurs in said cylinder, displays said misfire, and inhibits the fuel injection from the fuel injector 7 of said cylinder therein.

Inventors

• 👤 Sadayasu Ueno
• 👤 上野　定寧
• 👤 Norio Ichikawa
• 👤 市川　範男
• 👤 Fumio Isamigawa
• 👤 文雄 勇川
• 👤 Masaaki Uchida
• 👤 正明 内田
• 👤 Takayuki Itsuji
• 👤 貴之 井辻

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