US4226221A
Expired / Lapsed
US
⏱️ 0.0 years remaining
Closed loop mixture control system for internal combustion engine
Assignee: Nissan Motor Co Ltd
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Filing: 1979-04-10
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Granted: 1980-10-07
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Expires: 1999-04-10
Abstract
Abstract A closed loop mixture control system for an internal combustion engine comprises an exhaust gas sensor, a source of injecting a current into the exhaust gas sensor to develop a substantial voltage across the internal impedance thereof, and a variable reference setting circuit which establishes a variable reference voltage and reduces its value as a function of time such that the reference voltage lies between the maximum and minimum peak values of the output signal from the exhaust gas sensor.
Inventors
- 👤 Masaharu Asano
Bibliographic Details
Application Number
—
Jurisdiction
US
Data Source
google_patents
Last Synchronized
2026-10-26 20:05
CPC Classifications
F; F02; F02D; F02D41/00; F02D41/02; F02D41/14; F02D41/1438; F02D41/1477; F02D41/1479; F02D41/1444; F02D41/1454; F02D41/1455
Claims Analysis
Total Claims: 8
Claim 1
Independent Claim
164 words
A closed loop mixture control system for an internal combustion engine having an exhaust gas sensor for generating a signal representing the concentration of a predetermined constituent of the emissions of the engine, said exhaust gas sensor having an internal impedance which varies inversely as a function of temperature, and means for generating a signal representing the deviation of said concentration representative signal from a reference voltage to correct the air-fuel ratio of the mixture supplied to said engine, said deviation representative signal having a first voltage level corresponding to a lean mixture condition and a second voltage level corresponding to a rich mixture condition, comprising: means for injecting a current into said exhaust gas sensor to raise the voltage level of said concentration representative signal, whereby said voltage level decreases from a high to a low level as a function of temperature; and means for controlling said reference voltage to lie between the maximum and minimum peak values of said concentration representative signal.
Claim 2
Dependent Claim
164 words
A closed loop mixture control system for an internal combustion engine having an exhaust gas sensor for generating a signal representing the concentration of a predetermined constituent of the emissions of the engine, said exhaust gas sensor having an internal impedance which varies inversely as a function of temperature, and means for generating a signal representing the deviation of said concentration representative signal from a reference voltage to correct the air-fuel ratio of the mixture supplied to said engine, said deviation representative signal having a first voltage level corresponding to a lean mixture condition and a second voltage level corresponding to a rich mixture condition, comprising: means for injecting a current into said exhaust gas sensor to raise the voltage level of said concentration representative signal, whereby said voltage level decreases from a high to a low level as a function of temperature; and means for controlling said reference voltage to lie between the maximum and minimum peak values of said concentration representative signal.
Claim 3
Dependent Claim
99 words
A closed loop mixture control system as claimed in claim 1, wherein said controlling means comprises means for establishing said reference voltage at a given initial value, means for causing said reference voltage to reduce from said initial value as a function of time in response to said deviation representative signal having said first voltage level until said reference voltage reaches a point near the minimum peak value of said concentration representative signal, and means for detecting when said reference voltage reaches a point near the maximum peak value of said concentration representative signal to reduce said reference voltage.
Claim 4
Dependent Claim
70 words
A closed loop mixture control system as claimed in claim 1, wherein said controlling means comprises means for establishing said reference voltage at a given initial value, means for reducing said reference voltage from said initial value as a function of time in response to said deviation signal having said second voltage level until said reference voltage reaches a point near the minimum peak value of said concentration representative signal.
Claim 5
Dependent Claim
20 words
A closed loop mixture control system as claimed in claim 2 or 3, wherein said reference voltage is reduced stepwisely.
Claim 6
Dependent Claim
26 words
A closed loop mixture control system as claimed in claim 4, wherein said reference voltage is reduced in step with each revolution of the engine crankshaft.
Claim 7
Dependent Claim
87 words
A closed loop mixture control system as claimed in claim 2 or 3, wherein said reference establishing means comprises an integration circuit including an operational amplifier having an inverting and a noninverting input terminal and an output terminal, a capacitor connected between said inverting input terminal and said output terminal and a resistor connected at one end to said inverting input terminal and at the other end to a source of periodic pulses, said noninverting input being biased at a potential corresponding to said given initial value.
Claim 8
Dependent Claim
24 words
A closed loop mixture control system as claimed in claim 6, wherein said periodic pulses are synchronized with the revolution of the engine crankshaft.
References Cited (Backward Citations)
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USPTO Annuity & Maintenance Windows
| Annuity Stage | Window Opens | Payment Deadline | Surcharge Period Until | Estimated Fee | Status |
|---|---|---|---|---|---|
| 3.5 Years (Year 4) | 1983-10-07 | 1984-04-07 | 1984-10-07 | $2000.00 | Window Closed / Lapsed |
| 7.5 Years (Year 8) | 1987-10-07 | 1988-04-07 | 1988-10-07 | $3760.00 | Window Closed / Lapsed |
| 11.5 Years (Year 12) | 1991-10-07 | 1992-04-07 | 1992-10-07 | $7700.00 | Window Closed / Lapsed |