US4947819A
Expired / Lapsed
US
⏱️ 0.0 years remaining
Air-fuel ratio controller of internal combustion engine
Assignee: Mitsubishi Electric Corp
•
Filing: 1989-03-08
•
Granted: 1990-08-14
•
Expires: 2009-03-08
Abstract
Abstract The invention relates to an air-fuel (A/F) ratio controller of an internal combustion engine, which is provided with a constant-voltage circuit between the heater for heating the A/F ratio sensor and the power-supply source. Regardless of variation of voltage outputted from the power-supply source, the A/F ratio controller securely maintains the heater voltage constant and prevents occurrence of error in the signal outputted from the A/F ratio sensor by correctly operating the oxygen-concentration detecting element whose measuring precision is solely dependent on temperature.
Inventors
- 👤 Toshihisa Takahashi
- 👤 Masanobu Uchinami
- 👤 Ryoji Nishiyama
- 👤 Seiya Kominami
- 👤 Shinichi Nishida
Bibliographic Details
Application Number
—
Jurisdiction
US
Data Source
google_patents
Last Synchronized
2026-11-02 14:13
CPC Classifications
F; F02; F02D; F02D41/00; F02D41/02; F02D41/14; F02D41/1438; F02D41/1493; F02D41/1494; F02D41/1444; F02D41/1454; F02D41/1456
Claims Analysis
Total Claims: 2
Claim 1
Independent Claim
189 words
An air-fuel (A/F) ratio controller of an internal combustion engine comprising: an A/F ratio sensor which is composed of the following: an oxygen-concentration detecting element for generating electric signals responsive to the oxygen concentration of the exhaust gas of said engine, and a heater which heats said oxygen-concentration detecting element to a predetermined temperature; a controller for executing feedback control of a quantity of fuel to be supplied to said engine in accordance with electric signals generated by said oxygen-concentration detecting means so that the A/F ratio of the fuel-mixed vapor to be supplied to said engine can be predetermined A/F ratio; and a constant voltage circuit for maintaining voltage to be supplied to said heater constant; wherein said constant-voltage circuit is composed of the following: a Zener diode for lowering supply voltage to a predetermined voltage level, an operational amplifier whose one input terminal receives voltage from said Zener diode and whose other input terminal receives voltage representing the voltage to be supplied to said heater, and a transistor for adjusting said voltage to be supplied to said heater by applying base voltage received from said operational amplifier.
Claim 2
Dependent Claim
189 words
An air-fuel (A/F) ratio controller of an internal combustion engine comprising: an A/F ratio sensor which is composed of the following: an oxygen-concentration detecting element for generating electric signals responsive to the oxygen concentration of the exhaust gas of said engine, and a heater which heats said oxygen-concentration detecting element to a predetermined temperature; a controller for executing feedback control of a quantity of fuel to be supplied to said engine in accordance with electric signals generated by said oxygen-concentration detecting means so that the A/F ratio of the fuel-mixed vapor to be supplied to said engine can be predetermined A/F ratio; and a constant voltage circuit for maintaining voltage to be supplied to said heater constant; wherein said constant-voltage circuit is composed of the following: a Zener diode for lowering supply voltage to a predetermined voltage level, an operational amplifier whose one input terminal receives voltage from said Zener diode and whose other input terminal receives voltage representing the voltage to be supplied to said heater, and a transistor for adjusting said voltage to be supplied to said heater by applying base voltage received from said operational amplifier.
References Cited (Backward Citations)
US4019474A
Cited
US4121548A
Cited
US4332225A
Cited
US4471648A
Cited
US4464244A
Cited
JPS6072561A
Cited
US4611562A
Cited
DE3517252A1
Cited
US4721088A
Cited
US4873642A
Cited
US4765298A
Cited
US4889098A
Cited
US4895123A
Cited
USPTO Annuity & Maintenance Windows
| Annuity Stage | Window Opens | Payment Deadline | Surcharge Period Until | Estimated Fee | Status |
|---|---|---|---|---|---|
| 3.5 Years (Year 4) | 1993-08-13 | 1994-02-12 | 1994-08-14 | $2000.00 | Window Closed / Lapsed |
| 7.5 Years (Year 8) | 1997-08-13 | 1998-02-12 | 1998-08-14 | $3760.00 | Window Closed / Lapsed |
| 11.5 Years (Year 12) | 2001-08-13 | 2002-02-12 | 2002-08-14 | $7700.00 | Window Closed / Lapsed |