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US5224347A Expired / Lapsed US ⏱️ 0.0 years remaining

Method and apparatus for controlling the air-fuel ratio of a gas engine

Assignee: Tokyo Gas Co Ltd
•
Filing: 1991-09-06
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Granted: 1993-07-06
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Expires: 2011-09-06
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Abstract

Abstract A method and apparatus for controlling and improving the air-fuel ratio of a gas engine by controlling the air-fuel ratio on an exhaust purifying apparatus such as a three way catalyst in use with the gas engine. The method involves the steps of modulating a vibrational drive current for driving a bypass value with waveforms such as rectangular wave, sinusoidal wave, triangular wave, etc., with predetermined periods and amplitudes, in response to signals transmitted from a main oxygen sensor and a pressure sensor. The main oxygen sensor being installed on an up-stream side relative to the three way catalyst interposed on an exhaust line of the gas engine, and the pressure sensor being installed on an intake line in communication with a mixer; detecting distortion of responded waveforms of signals transmitted from a sub oxygen sensor, which sensor is installed on a down-stream side of the three way catalyst; and controlling the drive current so as to remove the detected distortions, in order to help optimize the air-fuel ratio of the gas engine. The invention thus helps in optimizing control of the air-fuel ratio and helps in the purification efficiency of the gas engine exhaust.

Inventors

  • 👤 Hisataka Yakabe
  • 👤 Masakazu Hishinuma

Bibliographic Details

Application Number —
Jurisdiction US
Data Source google_patents
Last Synchronized 2026-10-29 20:15
CPC Classifications
F; F02; F02D; F02D35/00; F02D35/0015; F02D35/0023; F02D35/003; F01; F01N; F01N11/00; F01N11/007; F02D41/00; F02D41/02; F02D41/14; F02D41/1438; F02D41/1439; F02D41/1441; F02D41/1486; F02D41/1487; F01N2430/00; F01N2430/06; F01N2550/00; F01N2550/02; Y; Y02; Y02T; Y02T10/00; Y02T10/10; Y02T10/12; Y02T10/40

Claims Analysis

Total Claims: 4
Claim 1
Independent Claim 132 words
Method for controlling air-fuel ratio of a gas engine, comprising the steps of: modulating a vibrational drive current for driving, with predetermined periods and amplitudes, a by-pass valve with a geometric waveform in response to signals transmitted from a main oxygen sensor and a pressure sensor, said main oxygen sensor being installed on an up-stream side relative to a three way catalyst interposed on an exhaust line of the gas engine, and said pressure sensor being installed on an intake line in line with a mixer; detecting distortions of responded waveforms of signals transmitted from a sub oxygen sensor installed on a down-stream side of said three way catalyst; and controlling said vibrational drive current so as to remove said distortions, in order to improve the air-fuel ratio of the gas engine.
Claim 2
Dependent Claim 132 words
Method for controlling air-fuel ratio of a gas engine, comprising the steps of: modulating a vibrational drive current for driving, with predetermined periods and amplitudes, a by-pass valve with a geometric waveform in response to signals transmitted from a main oxygen sensor and a pressure sensor, said main oxygen sensor being installed on an up-stream side relative to a three way catalyst interposed on an exhaust line of the gas engine, and said pressure sensor being installed on an intake line in line with a mixer; detecting distortions of responded waveforms of signals transmitted from a sub oxygen sensor installed on a down-stream side of said three way catalyst; and controlling said vibrational drive current so as to remove said distortions, in order to improve the air-fuel ratio of the gas engine.
Claim 3
Independent Claim 136 words
An apparatus for controlling air-fuel ratio of a gas engine, comprising: means modulating a vibrational drive current for driving a by-pass valve with a geometric waveform with predetermined periods and amplitudes, in response to signals transmitted from a main oxygen sensor and a pressure sensor, said main oxygen sensor being installed on an up-stream side relative to a three way catalyst interposed on an exhaust line of the gas engine, and said pressure sensor being installed on an intake line in line with a mixer; means for detecting distortions of responded waveforms of signals transmitted from a sub oxygen sensor is installed on a down-stream side of said three way catalyst; and means for controlling said vibrational drive current so as to remove said distortions, in order to improve the sir-fuel ratio of the gas engine.
Claim 4
Independent Claim 136 words
An apparatus for controlling air-fuel ratio of a gas engine, comprising: means modulating a vibrational drive current for driving a by-pass valve with a geometric waveform with predetermined periods and amplitudes, in response to signals transmitted from a main oxygen sensor and a pressure sensor, said main oxygen sensor being installed on an up-stream side relative to a three way catalyst interposed on an exhaust line of the gas engine, and said pressure sensor being installed on an intake line in line with a mixer; means for detecting distortions of responded waveforms of signals transmitted from a sub oxygen sensor is installed on a down-stream side of said three way catalyst; and means for controlling said vibrational drive current so as to remove said distortions, in order to improve the sir-fuel ratio of the gas engine.

References Cited (Backward Citations)

US4235204A Cited
US4378773A Cited
US4375796A Cited

USPTO Annuity & Maintenance Windows

Annuity Stage Window Opens Payment Deadline Surcharge Period Until Estimated Fee Status
3.5 Years (Year 4) 1996-07-05 1997-01-04 1997-07-06 $2000.00 Window Closed / Lapsed
7.5 Years (Year 8) 2000-07-05 2001-01-04 2001-07-06 $3760.00 Window Closed / Lapsed
11.5 Years (Year 12) 2004-07-05 2005-01-04 2005-07-06 $7700.00 Window Closed / Lapsed

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