US4886028A
Expired / Lapsed
US
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Apparatus for controlling air-fuel ratio of internal combustion engine
Assignee: Mitsubishi Electric Corp
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Filing: 1989-02-15
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Granted: 1989-12-12
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Expires: 2009-02-15
Abstract
Abstract An air-fuel ratio control apparatus for an internal combustion engine comprises feedback control of the air-fuel ratio control, wherein a pump-driving voltage for flowing a pump-driving current is lowered to a predetermined value, and feedback control is suspended when the pump-driving current becomes lower than a predetermined value.
Inventors
- 👤 Masanobu Uchinami
- 👤 Toshihisa Takahashi
- 👤 Hiroyoshi Suzuki
- 👤 Ryoji Nishiyama
- 👤 Shinichi Nishida
Bibliographic Details
Application Number
—
Jurisdiction
US
Data Source
google_patents
Last Synchronized
2026-10-29 09:22
CPC Classifications
F; F02; F02D; F02D41/00; F02D41/02; F02D41/14; F02D41/1438; F02D41/1473; F02D41/1475; F02D41/1476; F02D41/1486; F02D41/1488; F02D41/1493; F02D41/1495
Claims Analysis
Total Claims: 4
Claim 1
Independent Claim
214 words
An air-fuel ratio control apparatus for an internal combustion engine, said apparatus including a wide range air-fuel ratio sensor, which includes an oxygen sensor section for generating a voltage in accordance with the difference between atmospheric pressure and the oxygen concentration of the engine exhaust gas and an oxygen pump section for flowing a pump-driving current so as to attain said voltage at a predetermined value, an air-fuel ratio detecting device for providing an air-fuel ratio detecting signal in response to said pump-driving current, and a control section for feedback-controlling a mixed gas generation means in accordance with said air-fuel ratio detecting signal to obtain an air-fuel ratio having a required value, said apparatus further comprising a deterioration detecting means for detecting any deterioration or failure of the wide range air-fuel ratio sensor by detecting that the pump-driving current is lower than a predetermined value when the pump-driving voltage for flowing the pump-driving current is set to a predetermined value lower than the ordinary pump-driving voltage while the engine is running in a steady conditon at which time the air-fuel ratio is within a predetermined range, and a feedback suspension means for stopping the feedback control of the air-fuel ratio when such deterioration or failure of the wide range air-fuel ratio sensor is detected.
Claim 2
Dependent Claim
214 words
An air-fuel ratio control apparatus for an internal combustion engine, said apparatus including a wide range air-fuel ratio sensor, which includes an oxygen sensor section for generating a voltage in accordance with the difference between atmospheric pressure and the oxygen concentration of the engine exhaust gas and an oxygen pump section for flowing a pump-driving current so as to attain said voltage at a predetermined value, an air-fuel ratio detecting device for providing an air-fuel ratio detecting signal in response to said pump-driving current, and a control section for feedback-controlling a mixed gas generation means in accordance with said air-fuel ratio detecting signal to obtain an air-fuel ratio having a required value, said apparatus further comprising a deterioration detecting means for detecting any deterioration or failure of the wide range air-fuel ratio sensor by detecting that the pump-driving current is lower than a predetermined value when the pump-driving voltage for flowing the pump-driving current is set to a predetermined value lower than the ordinary pump-driving voltage while the engine is running in a steady conditon at which time the air-fuel ratio is within a predetermined range, and a feedback suspension means for stopping the feedback control of the air-fuel ratio when such deterioration or failure of the wide range air-fuel ratio sensor is detected.
Claim 3
Independent Claim
196 words
A method of controlling the operation of an air-fuel ratio control apparatus for an internal combustion engine, said apparatus comprising a wide range air-fuel ratio sensor which includes an oxygen sensor section for generating a voltage in accordance with the difference between atmospheric pressure and the oxygen concentration of the engine exhaust gas and an oxygen pump section for flowing a pump-driving current so as to attain said voltage at a predetermined value, an air-fuel ratio detecting device for providing an air-fuel ratio detecting signal in response to said pump-driving current, and a control section for feedback-controlling a mixed gas generating means in accordance with said air-fuel ratio detecting signal to obtain an air-fuel ratio having a required value, said method comprising the steps of: setting the pump-driving voltage for flowing the pump-driving current to a predetermined value lower than the normal pump-driving voltage while the engine is being driven in a steady condition under which the air-fuel ratio is within a predetermined range; detecting whether or not the pump-driving current is lower than a predetermined value; and suspending the feedback control of the air-fuel ratio when the pump-driving current is lower than the predetermined value.
Claim 4
Independent Claim
196 words
A method of controlling the operation of an air-fuel ratio control apparatus for an internal combustion engine, said apparatus comprising a wide range air-fuel ratio sensor which includes an oxygen sensor section for generating a voltage in accordance with the difference between atmospheric pressure and the oxygen concentration of the engine exhaust gas and an oxygen pump section for flowing a pump-driving current so as to attain said voltage at a predetermined value, an air-fuel ratio detecting device for providing an air-fuel ratio detecting signal in response to said pump-driving current, and a control section for feedback-controlling a mixed gas generating means in accordance with said air-fuel ratio detecting signal to obtain an air-fuel ratio having a required value, said method comprising the steps of: setting the pump-driving voltage for flowing the pump-driving current to a predetermined value lower than the normal pump-driving voltage while the engine is being driven in a steady condition under which the air-fuel ratio is within a predetermined range; detecting whether or not the pump-driving current is lower than a predetermined value; and suspending the feedback control of the air-fuel ratio when the pump-driving current is lower than the predetermined value.
References Cited (Backward Citations)
USPTO Annuity & Maintenance Windows
| Annuity Stage | Window Opens | Payment Deadline | Surcharge Period Until | Estimated Fee | Status |
|---|---|---|---|---|---|
| 3.5 Years (Year 4) | 1992-12-11 | 1993-06-12 | 1993-12-12 | $2000.00 | Window Closed / Lapsed |
| 7.5 Years (Year 8) | 1996-12-11 | 1997-06-12 | 1997-12-12 | $3760.00 | Window Closed / Lapsed |
| 11.5 Years (Year 12) | 2000-12-11 | 2001-06-12 | 2001-12-12 | $7700.00 | Window Closed / Lapsed |