ABNORMALITY DETECTING DEVICE FOR AIR-FUEL RATIO SENSORS, CONTROL DEVICE FOR AIR-FUEL RATIO SENSORS, AND ABNORMALITY DETECTING METHOD

• Main Authors: KOMIYA MOTOKI, MORISAKI CHIHARU, WATANABE MASATOSHI, UMEYAMA SHIGETO, MIURA HIROTO, KIDO KEISUKE
• Format: Patent
• Language: English; Japanese
• Published: 25.05.2017
• Subjects: INVESTIGATING OR ANALYSING MATERIALS BY DETERMINING THEIRCHEMICAL OR PHYSICAL PROPERTIES; MEASURING; PHYSICS; TESTING

PROBLEM TO BE SOLVED: To make possible accurate detection of abnormality in which two ends of the detection cell of a gas sensor element are short-circuited.SOLUTION: An abnormality detecting device for air-fuel ratio sensors is equipped with an inter-terminal voltage detecting unit, a terminal voltage detecting unit and an abnormality determining unit. The inter-terminal voltage detecting unit detects the voltage between a first terminal to which one end of a detecting cell is connected and a second terminal to which the other end of the detecting cell is connected. The terminal voltage detecting unit detects the voltage of the second terminal that varies with a current for measuring use supplied between the first terminal and the second terminal to measure the state of impedance of the detecting cell. The abnormality determining unit determines the short-circuiting state between the first terminal and the second terminal on the basis of the quantity of variation by the current for measuring the voltage detected by the inter-terminal voltage detecting unit and the voltage detected by the inter-terminal voltage detecting unit.SELECTED DRAWING: Figure 1 【課題】ガスセンサ素子の検出セルの両端がショートする異常を精度よく検出すること。【解決手段】実施形態にかかる空燃比センサの異常検出装置は、端子間電圧検出部と、端子電圧検出部と、異常判定部とを備える。端子間電圧検出部は、検出セルの一端が接続される第１端子と検出セルの他端が接続される第２端子との間の電圧を検出する。端子電圧検出部は、検出セルのインピーダンスの状態を測定するために第１端子と第２端子との間に供給される測定用電流によって変化する第２端子の電圧を検出する。異常判定部は、端子間電圧検出部によって検出される電圧の測定用電流による変化量と端子間電圧検出部によって検出される電圧とに基づいて、第１端子と第２端子との間のショート状態を判定する。【選択図】図１