US4723519A
Expired / Lapsed
US
⏱️ 0.0 years remaining
Ignition timing control system for an internal combustion engine
Assignee: Denso Ten Ltd
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Filing: 1986-06-16
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Granted: 1988-02-09
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Expires: 2006-06-16
Abstract
Abstract An ignition timing control system mounted at an internal combustion engine, particularly, a non-surge tank type engine, is constituted by a crank angle sensor, an engine rotational speed sensor, an intake pipe air pressure sensor, and a microcomputer. In the microcomputer, an intake pipe air pressure correction unit for calculating a correction term and for obtaining a corrected intake pipe air pressure value, an optimal advanced angle calculation unit for obtaining an optimal advanced crank angle based on a control map having an optimal advanced angle between the corrected intake pipe air pressure and the engine rotational speed, and an ignition command unit for commanding an ON/OFF timing of a primary current of an ignition coil, are provided.
Inventors
- 👤 Toshimitsu Ito
- 👤 Akira Mori
Bibliographic Details
Application Number
—
Jurisdiction
US
Data Source
google_patents
Last Synchronized
2026-10-29 23:11
CPC Classifications
F; F02; F02P; F02P5/00; F02P5/04; F02P5/145; F02P5/155; F02P5/1553; F02P5/1555; F02P5/05; F02P5/10; F02P5/103; F02P5/106; Y; Y02; Y02T; Y02T10/00; Y02T10/10; Y02T10/40
Claims Analysis
Total Claims: 7
Claim 1
Independent Claim
243 words
An ignition timing control system for an internal combustion engine comprising: a crank angle detection means for detecting a crank angle; an engine rotational speed detection means for detecting engine rotational speed; an intake pipe air pressure detection means for detecting air pressure in an intake manifold; an intake pipe air pressure detection means for calculating a correction term and for obtaining a corrected intake pipe air pressure value, comprising a first difference value calculation means for obtaining a first difference value before and after each period of the intake pipe air pressure, a calculation means for obtaining a second difference value second difference value before and after each first difference value, a correction calculation means for obtaining a correction term based on the second difference value and a correction factor, and a corrected pressure calculation means for obtaining the corrected intake pipe air pressure value by adding the correction term, wherein when said second difference value exceeds a predetermined reference value, the correction term corresponding to said second difference value is calculated and added to the intake pipe air pressure; an optimal advanced angle calculation means for obtaining an optimal advanced crank angle based on a corrected intake pipe pressure obtained by said intake pipe air pressure correction means and based on an engine rotational speed obtained by said engine rotational speed detection means; and an ignition command means for commanding an ON/OFF timing of a primary current of an ignition coil.
Claim 2
Dependent Claim
243 words
An ignition timing control system for an internal combustion engine comprising: a crank angle detection means for detecting a crank angle; an engine rotational speed detection means for detecting engine rotational speed; an intake pipe air pressure detection means for detecting air pressure in an intake manifold; an intake pipe air pressure detection means for calculating a correction term and for obtaining a corrected intake pipe air pressure value, comprising a first difference value calculation means for obtaining a first difference value before and after each period of the intake pipe air pressure, a calculation means for obtaining a second difference value second difference value before and after each first difference value, a correction calculation means for obtaining a correction term based on the second difference value and a correction factor, and a corrected pressure calculation means for obtaining the corrected intake pipe air pressure value by adding the correction term, wherein when said second difference value exceeds a predetermined reference value, the correction term corresponding to said second difference value is calculated and added to the intake pipe air pressure; an optimal advanced angle calculation means for obtaining an optimal advanced crank angle based on a corrected intake pipe pressure obtained by said intake pipe air pressure correction means and based on an engine rotational speed obtained by said engine rotational speed detection means; and an ignition command means for commanding an ON/OFF timing of a primary current of an ignition coil.
Claim 3
Dependent Claim
23 words
A system as claimed in claim 1, wherein said first and second difference values are calculated when an idle switch is turned OFF.
Claim 4
Dependent Claim
21 words
A system as claimed in claim 1, wherein said predetermined reference value is changed in correspondence with the engine rotational speed.
Claim 5
Dependent Claim
19 words
A system as claimed in claim 1, wherein said correction factor is changed in correspondence with the correction term.
Claim 6
Dependent Claim
27 words
A system as claimed in claim 1, wherein a constant pressure value is subtracted from the correction term at each period of the intake pipe air pressure.
Claim 7
Dependent Claim
21 words
A system as claimed in claim 5, wherein said correction term is treated as zero when said subtraction result is negative.
References Cited (Backward Citations)
DE3011892A1
Cited
US4412520A
Cited
EP0046305A2
Cited
JPS5738642A
Cited
GB2120406A
Cited
US4633839A
Cited
USPTO Annuity & Maintenance Windows
| Annuity Stage | Window Opens | Payment Deadline | Surcharge Period Until | Estimated Fee | Status |
|---|---|---|---|---|---|
| 3.5 Years (Year 4) | 1991-02-08 | 1991-08-10 | 1992-02-09 | $2000.00 | Window Closed / Lapsed |
| 7.5 Years (Year 8) | 1995-02-08 | 1995-08-10 | 1996-02-09 | $3760.00 | Window Closed / Lapsed |
| 11.5 Years (Year 12) | 1999-02-08 | 1999-08-10 | 2000-02-09 | $7700.00 | Window Closed / Lapsed |