O2-Sensor fault diagnosis apparatus and method therefor
First Claim
1. An O2-sensor fault diagnosis apparatus comprising:
- an O2-sensor for detecting concentration of oxygen contained in an exhaust gas of an internal combustion engine;
a feedback control portion for controlling a quantity of fuel supplied to the internal combustion engine through feedback control according to an output signal of the O2-sensor;
a state judging portion for judging whether the O2-sensor is in an active state or in an inactive state on the basis of an voltage of the output signal of the O2-sensor; and
a fault diagnosis portion for diagnosing whether the O2-sensor has any fault on the basis of the voltage of the output signal of the O2-sensor under a condition where it is judged that the O2-sensor is in the inactive state.
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Accused Products
Abstract
An O2-sensor fault diagnosis apparatus and method therefor, which are capable of detecting wire breaking of an O2-sensor with reliability and successively performing fault diagnosis with minimal effect on an exhaust gas. An O2-sensor 19 detects concentration of oxygen contained in an exhaust gas of an engine 1. An ECU 20 controls a quantity of fuel supplied to the engine 1 through feedback control according to an output signal of the O2-sensor. A fault diagnosis portion changes an input resistance value of an input circuit that is connected to the O2-sensor 19 and constitutes the ECU 20 each time a control condition for determining that the O2-sensor 19 is in an inactive state is satisfied, determines that wire breaking occurs in the O2-sensor 19 only if the output voltage of the O2-sensor 19 exceeds a predetermined voltage, and activates an informing portion to send a notice showing that there is a fault in the O2-sensor 19.
13 Citations
8 Claims
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1. An O2-sensor fault diagnosis apparatus comprising:
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an O2-sensor for detecting concentration of oxygen contained in an exhaust gas of an internal combustion engine;
a feedback control portion for controlling a quantity of fuel supplied to the internal combustion engine through feedback control according to an output signal of the O2-sensor;
a state judging portion for judging whether the O2-sensor is in an active state or in an inactive state on the basis of an voltage of the output signal of the O2-sensor; and
a fault diagnosis portion for diagnosing whether the O2-sensor has any fault on the basis of the voltage of the output signal of the O2-sensor under a condition where it is judged that the O2-sensor is in the inactive state. - View Dependent Claims (2, 3, 4)
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5. An O2-sensor fault diagnosis method comprising:
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a state judging step for judging whether an O2-sensor, which detects concentration of oxygen contained in an exhaust gas of an internal combustion engine, is in an active state or in an inactive state on the basis of an voltage of an output signal of the O2-sensor; and
a fault diagnosis step for diagnosing whether the O2-sensor has any fault on the basis of the voltage of the output signal of the O2-sensor under a condition where it is judged that the O2-sensor is in the inactive state. - View Dependent Claims (6, 7, 8)
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Specification