Method of abnormality detection of oxygen concentration sensor

Patent · Tue Oct 18 04:00:00 EDT 1988

OSTI ID:6620805

Mieno, T; Nakajima, T; Okada, Y; Oono, N

This patent describes a method for controlling an air/fuel ratio of the intake air-fuel mixture of an internal combustion engine provided with an oxygen concentration sensor at the exhaust system thereof, the sensor including a sensor unit having oxygen pump and sensor cell elements forming a gas diffusion central region therebetween into which the exhaust gas is supplied, voltage supply means for supplying a pump voltage determined in accordance with deviation of a sensor voltage appearing across the sensor cell element from a reference voltage so as to maintain the sensor voltage at the reference voltage, and signal generating means for generating an oxygen concentration signal varying with a pump current flowing through the oxygen pump element, the method comprising: setting a target air/fuel ration in accordance with the load of the engine; determining an air/fuel ratio control valve in accordance with an engine operating conditions of the engine while comparing the oxygen concentration signal with the target air/fuel ratio; controlling the intake air/fuel ratio in accordance with the air/fuel ratio control value; detecting an appearance of a sensor value normally indicative of a rich condition in which the sensed intake air/fuel ratio is within a rich region; comparing the sensor voltage with the reference voltage; and determining an abnormality of the oxygen concentration sensor according to when the sensor voltage is lower than the reference voltage upon detection of the rich condition in the step of detecting.

• Assignee: Honda Giken Kogyo Kabushiki Kaisha, Tokyo
• Patent Number(s): US 4777922
• OSTI ID: 6620805
• Country of Publication: United States
• Language: English

Related Subjects

33 ADVANCED PROPULSION SYSTEMS
330100* -- Internal Combustion Engines
CONTROL
CONTROL EQUIPMENT
DETECTION
ELECTRIC MEASURING INSTRUMENTS
ELECTRICAL EQUIPMENT
ELEMENTS
ENGINES
EQUIPMENT
EXHAUST SYSTEMS
FLOW REGULATORS
FUEL SYSTEMS
FUEL-AIR RATIO
HEAT ENGINES
INTERNAL COMBUSTION ENGINES
MEASURING INSTRUMENTS
METERING
METERS
NONMETALS
OPERATION
OXYGEN
VALVES