US4753204A
Expired / Lapsed
US
⏱️ 0.0 years remaining
Air-fuel ratio control system for internal combustion engines
Assignee: Mitsubishi Electric Corp
•
Filing: 1987-09-28
•
Granted: 1988-06-28
•
Expires: 2007-09-28
Abstract
Abstract An air-fuel ratio control system for internal combustion engines has an air-fuel ratio sensor mounted in an exhaust pipe of an internal combustion engine and is adapted to produce an output indicative of the air-fuel ratio of a mixture supplied to the engine, on the basis of the composition of exhaust gases in the exhaust pipe. The air-fuel ratio sensor is provided with an electric heater for heating the air-fuel ratio sensor. The system further has a temperature sensor for sensing the temperature of the internal combustion engine or the ambient air temperature, and an engine operation sensor adapted to sense whether the engine has been stopped, through detection of the state of the ignition switch. When the engine operation sensor has sensed that the internal combustion engine has been stopped while the temperature sensed by the temperature sensor is below a predetermined level, the electric heater is supplied with power for a predetermined time after the stop of the engine so as to evaporate any water content clinging to the air-fuel ratio sensor.
Inventors
- 👤 Shinji Kojima
- 👤 Seiji Wataya
- 👤 Ryoji Nishiyama
Bibliographic Details
Application Number
—
Jurisdiction
US
Data Source
google_patents
Last Synchronized
2026-10-30 05:55
CPC Classifications
F; F02; F02D; F02D41/00; F02D41/02; F02D41/14; F02D41/1438; F02D41/1493; F02D41/1494; F02D41/04; F02D41/042
Claims Analysis
Total Claims: 12
Claim 1
Independent Claim
146 words
An air-fuel ratio control system for internal combustion engines, comprising: an air-fuel ratio sensor mounted in an exhaust pipe of an internal combustion engine and adapted to produce an output indicative of the air-fuel ratio of a mixture supplied to said engine on the basis of the composition of exhaust gases in said exhaust pipe; heating means for heating said air-fuel ratio sensor; a temperature sensor for sensing the temperature of said internal combustion engine; an engine operation sensor adapted to sense whether said engine has been stopped; and control means for allowing, when said engine operation sensor has sensed that said internal combustion engine has been stopped while the engine temperature sensed by said temperature sensor is below a predetermined level, said heating means to operate for a predetermined time after said engine operation sensor has sensed that said internal combustion engine has been stopped.
Claim 2
Dependent Claim
146 words
An air-fuel ratio control system for internal combustion engines, comprising: an air-fuel ratio sensor mounted in an exhaust pipe of an internal combustion engine and adapted to produce an output indicative of the air-fuel ratio of a mixture supplied to said engine on the basis of the composition of exhaust gases in said exhaust pipe; heating means for heating said air-fuel ratio sensor; a temperature sensor for sensing the temperature of said internal combustion engine; an engine operation sensor adapted to sense whether said engine has been stopped; and control means for allowing, when said engine operation sensor has sensed that said internal combustion engine has been stopped while the engine temperature sensed by said temperature sensor is below a predetermined level, said heating means to operate for a predetermined time after said engine operation sensor has sensed that said internal combustion engine has been stopped.
Claim 3
Dependent Claim
99 words
An air-fuel ratio control system for internal combustion engines according to claim 1, wherein said control means includes temperature determining means for determining whether the engine temperature sensed by said temperature sensor is below said predetermined level, and a timer adapted to allow, when said engine operation sensor has sensed that said internal combustion engine has been stopped while the engine temperature is determined by said temperature determining means to be below said predetermined level, said heating means to operate for a predetermined time after said engine operation sensor has sensed that said internal combustion engine has been stopped.
Claim 4
Dependent Claim
21 words
An air-fuel ratio control system for internal combustion engines according to claim 1, wherein said heating means comprises an electric heater.
Claim 5
Dependent Claim
29 words
An air-fuel ratio control system for internal combustion engines according to claim 3, wherein said timer controls the length of time of electric power supply to said electric heater.
Claim 6
Dependent Claim
36 words
An air-fuel ratio control system for internal combustion engines according to claim 1, wherein said engine operation sensor senses that said engine has been stopped, upon detecting turning off of the ignition switch of said engine.
Claim 7
Dependent Claim
145 words
An air-fuel ratio control system for internal combustion engines, comprising: an air-fuel ratio sensor mounted in an exhaust pipe of an internal combustion engine and adapted to produce an output indicative of the air-fuel ratio of a mixture supplied to said engine on the basis of the composition of exhaust gases in said exhaust pipe; heating means for heating said air-fuel ratio sensor; a temperature sensor for sensing the temperature of ambient air; an engine operation sensor adapted to sense whether said engine has been stopped; and control means for allowing, when said engine operation sensor has sensed that said internal combustion engine has been stopped while the ambient air temperature sensed by said temperature sensor is below a predetermined level, said heating means to operate for a predetermined time after said engine operation sensor has sensed that said internal combustion engine has been stopped.
Claim 8
Dependent Claim
145 words
An air-fuel ratio control system for internal combustion engines, comprising: an air-fuel ratio sensor mounted in an exhaust pipe of an internal combustion engine and adapted to produce an output indicative of the air-fuel ratio of a mixture supplied to said engine on the basis of the composition of exhaust gases in said exhaust pipe; heating means for heating said air-fuel ratio sensor; a temperature sensor for sensing the temperature of ambient air; an engine operation sensor adapted to sense whether said engine has been stopped; and control means for allowing, when said engine operation sensor has sensed that said internal combustion engine has been stopped while the ambient air temperature sensed by said temperature sensor is below a predetermined level, said heating means to operate for a predetermined time after said engine operation sensor has sensed that said internal combustion engine has been stopped.
Claim 9
Dependent Claim
102 words
An air-fuel ratio control system for internal combustion engines according to claim 1, wherein said control means includes temperature determining means for determining whether the ambient air temperature sensed by said temperature sensor is below said predetermined level, and a timer adapted to allow, when said engine operation sensor has sensed that said internal combustion engine has been stopped while the ambient air temperature is determined by said temperature determining means to be below said predetermined level, said heating means to operate for a predetermined time after said engine operation sensor has sensed that said internal combustion engine engine has been stopped.
Claim 10
Dependent Claim
21 words
An air-fuel ratio control system for internal combustion engines according to claim 1, wherein said heating means comprises an electric heater.
Claim 11
Dependent Claim
29 words
An air-fuel ratio control system for internal combustion engines according to claim 3, wherein said timer controls the length of time of electric power supply to said electric heater.
Claim 12
Dependent Claim
36 words
An air-fuel ratio control system for internal combustion engines according to claim 1, wherein said engine operation sensor senses that said engine has been stopped, upon detecting turning off of the ignition switch of said engine.
References Cited (Backward Citations)
US4541899A
Cited
US4332225A
Cited
US4464244A
Cited
US4500412A
Cited
JPS60125553A
Cited
US4683539A
Cited
US4594987A
Cited
US4611562A
Cited
JPS60235045A
Cited
US4639305A
Cited
US4650560A
Cited
US4694806A
Cited
US4715343A
Cited
US4706634A
Cited
USPTO Annuity & Maintenance Windows
| Annuity Stage | Window Opens | Payment Deadline | Surcharge Period Until | Estimated Fee | Status |
|---|---|---|---|---|---|
| 3.5 Years (Year 4) | 1991-06-28 | 1991-12-28 | 1992-06-28 | $2000.00 | Window Closed / Lapsed |
| 7.5 Years (Year 8) | 1995-06-28 | 1995-12-28 | 1996-06-28 | $3760.00 | Window Closed / Lapsed |
| 11.5 Years (Year 12) | 1999-06-28 | 1999-12-28 | 2000-06-28 | $7700.00 | Window Closed / Lapsed |