Method and apparatus for discriminating operativeness/inoperativeness of an air-fuel ratio sensor

Patent · Tue Jul 07 04:00:00 EDT 1987

OSTI ID:6042224

Takao, M

An apparatus is described for discriminating operativeness/inoperativeness of an air-fuel ratio sensor which produces an output signal indicative of air-fuel ratio, provided in an exhaust passage of an internal combustion engine so that an air-fuel ratio of mixture to the engine is feedback-controlled in response to an output signal of the air-fuel ratio sensor, the apparatus comprising: means for comparing the output signal of the air-fuel ratio sensor with a predetermined reference level; means for calculating a difference between the output signal of the air-fuel ratio sensor and the predetermined reference level; means for integrating, for a predetermined interval of time, the difference calculated by the calculating means to produce an integration value; means for comparing the integration value produced by the integrating means with a predetermined discrimination reference, so that operativeness/inoperativeness of the air-fuel ratio sensor is discriminated in response to a comparison output of the comparing means; and means for enabling the difference calculating means to calculate the difference in response to an output of the output signal comparing means indicative of an attainment of the output signal of the air-fuel ratio sensor at the predetermined reference level.

• Assignee: Nippondenso Co., Ltd., Kariya
• Patent Number(s): US 4677955
• OSTI ID: 6042224
• Country of Publication: United States
• Language: English

Related Subjects

33 ADVANCED PROPULSION SYSTEMS
330100* -- Internal Combustion Engines
COMPUTER CALCULATIONS
COMPUTERIZED CONTROL SYSTEMS
CONTROL SYSTEMS
DISPERSIONS
ENGINES
EXHAUST SYSTEMS
FEEDBACK
FUEL GAGES
FUEL INJECTION SYSTEMS
FUEL SYSTEMS
FUEL-AIR RATIO
HEAT ENGINES
INTERNAL COMBUSTION ENGINES
MEASURING INSTRUMENTS
MIXTURES
MONITORS
SIGNALS