Abnormality diagnosing device for internal combustion engine

Abstract

Abstract PURPOSE:To make installation of a specially prepared abnormality diagnosing means unnecessary, by counting the number of repetition of the shifting of the air-fuel ratio rich to lean or lean to rich in idling condition of an engine in the above caption, and judging a fuel injection valve to be abnormal when the number of the above repetition of the shifting per a specified time exceeds a predetermined value. CONSTITUTION:In an internal combustion engine provided with a fuel injection valve for each of its cylinders, as air-fuel ratio feed back means B is provided which makes feed back control of air-fuel ratio in response to the output of a air-fuel ratio sensing means A installed in the exhaust gas passage of said engine And a frequency sensing means D is installed which measure the air-fuel ratio feed back frequency (the number of rich/lean shifting of the air-fuel ratio) when an idling detecting means C detects the idling state of said engine. Then, the measured frequency is compared with a predetermined value by a comparing means E, and, if the measured frequency is higher than the predetermined value, it is judged that one or more of the fuel injection valves should be abnormal, this abnormality of the injection values to be indicated on a displaying means F to warn the operator of said engine.

Inventors

• 👤 Yoshiaki Kinoshita
• 👤 木下　美明
• 👤 Yutaka Sawada
• 👤 裕 沢田

Bibliographic Details