Patent US4407247A successfully refreshed from Google Patents.
US4407247A
Expired / Lapsed
US
⏱️ 0.0 years remaining
Closed loop type air-fuel ratio control system of an internal combustion engine
Assignee: Nissan Motor Co Ltd
•
Filing: 1981-10-21
•
Granted: 1983-10-04
•
Expires: 2001-10-21
Abstract
Abstract In an internal combustion engine having at its intake section a two-barrel type carburetor including a primary fuel supply system having a primary main fuel supply line and a primary slow fuel supply line and a secondary fuel supply system having a secondary main fuel supply line and a secondary step fuel supply line, and at its exhaust section a three-way catalytic converter, there is provided an improved closed loop type air-fuel ratio control system which controls not only the amount of air fed to the primary main and slow fuel supply lines but also the amount of air fed to the secondary main and step fuel supply lines in accordance with the concentration of a selected component of the engine exhaust gas. A switching valve is associated with both the primary slow fuel supply line and the secondary main or step fuel supply line so as to alter the course of the air introduction into the primary slow fuel supply line or into the secondary main or step fuel supply line in accordance with the engine load.
Inventors
- 👤 Kenji Masaki
Bibliographic Details
Application Number
—
Jurisdiction
US
Data Source
google_patents
Last Synchronized
2026-10-26 14:38
CPC Classifications
F; F02; F02D; F02D41/00; F02D41/02; F02D41/14; F02D41/1438; F02D41/1486; F02D41/1488; F02D41/149; F02M; F02M3/00; F02M3/08; F02M3/09; F02M7/00; F02M7/23; F02M7/24
Claims Analysis
Total Claims: 7
Claim 1
Independent Claim
261 words
In an internal combustion engine having at its intake section a two-barrel type carburetor including a primary fuel supply system having a primary main fuel supply line and a primary slow fuel supply line and a secondary fuel supply system having a secondary main fuel supply line and a secondary step fuel supply line, and at its exhaust section a three-way catalytic converter disposed in an exhaust tube of said engine, a closed loop type air-fuel ratio control system comprising: an exhaust gas sensor for producing an information signal representative of the air-fuel ratio of the engine inlet mixture by sensing the engine exhaust gas; a control unit for producing a command signal by processing said information signal issued from said exhaust gas sensor; first means for controlling the amount of air fed to said primary main fuel supply line in accordance with the command signal from said control unit; second means having first and second conditions which take place selectively, said first condition being a condition wherein said second means controls the amount of air fed to said primary slow fuel supply line in accordance with the command signal from said control unit, said second condition being a condition wherein said second means controls the amount of air fed to either of said secondary main fuel supply line and said secondary step fuel supply line in accordance with the command signal from said control unit, and third means for causing said second means to assume selectively said first and second conditions in accordance with the load applied to the engine.
Claim 2
Dependent Claim
261 words
In an internal combustion engine having at its intake section a two-barrel type carburetor including a primary fuel supply system having a primary main fuel supply line and a primary slow fuel supply line and a secondary fuel supply system having a secondary main fuel supply line and a secondary step fuel supply line, and at its exhaust section a three-way catalytic converter disposed in an exhaust tube of said engine, a closed loop type air-fuel ratio control system comprising: an exhaust gas sensor for producing an information signal representative of the air-fuel ratio of the engine inlet mixture by sensing the engine exhaust gas; a control unit for producing a command signal by processing said information signal issued from said exhaust gas sensor; first means for controlling the amount of air fed to said primary main fuel supply line in accordance with the command signal from said control unit; second means having first and second conditions which take place selectively, said first condition being a condition wherein said second means controls the amount of air fed to said primary slow fuel supply line in accordance with the command signal from said control unit, said second condition being a condition wherein said second means controls the amount of air fed to either of said secondary main fuel supply line and said secondary step fuel supply line in accordance with the command signal from said control unit, and third means for causing said second means to assume selectively said first and second conditions in accordance with the load applied to the engine.
Claim 3
Dependent Claim
115 words
A closed loop type air-fuel ratio control system as claimed in claim 1, in which said first means comprises: a first conduit means extending from said primary main fuel supply line for introducing air into said line; a first electromagnetic valve disposed in said first conduit means and electrically connected to said control unit to control the air flow rate in the first conduit means in response to the command signal from the control unit; and a vacuum operated air flow rate controller disposed in said first conduit means for controlling the flow rate of air in said first conduit means in accordance with the negative pressure created in the primary barrel of the carburetor.
Claim 4
Dependent Claim
191 words
A closed loop type air-fuel ratio control system as claimed in claim 1 or 2, in which said second means comprises: a second conduit means extending from said primary slow fuel supply line for introducing air into said line; a second electromagnetic valve disposed in said second conduit means and electrically connected to said control unit to control the air flow rate in said second conduit means in response to the command signal from the control unit; a third conduit means having one end connected to said second conduit means at a portion downstream of said second electromagnetic valve and the other end connected to said secondary main fuel supply line; a third electromagnetic valve disposed in said third conduit means and electrically connected to said control unit to selectively open and close the third conduit means in response to the command signal from said control unit; and a fourth electromagnetic valve associated with said primary slow fuel supply line and electrically connected to said control unit to selectively open and close said line, while permitting air introduction into the same, in response to the command signal from said control unit.
Claim 5
Dependent Claim
82 words
A closed loop type air-fuel ratio control system as claimed in claim 3, in which said third means comprises: a primary throttle switch electrically connected to said control unit and issuing respectively different information signals when the primary throttle valve of said primary fuel supply system is fully closed and open; a secondary throttle switch electrically connected to said control unit and issuing another information signal when said secondary throttle valve of said secondary fuel supply system opens by a predetermined degree.
Claim 6
Dependent Claim
119 words
A closed loop type air-fuel ratio control system as claimed in claim 3, in which said second means further comprises: a fourth conduit means having one end connected to said third conduit means at a portion downstream of said third electromagnetic valve and the other end connected to the secondary step fuel supply line; and an electromagnetic two-way valve arranged in the portion where said fourth conduit means is united with said third conduit means, said two-way valve being electrically connected to said control unit to change the air flow into the secondary main fuel supply line to that into the secondary step fuel supply line or, vice versa, in response to the command signal from said control unit.
Claim 7
Dependent Claim
63 words
A closed loop type air-fuel ratio control system as claimed in claim 5, in which said secondary throttle switch of said third means issues a still another information signal, when said secondary throttle valve opens beyond said predetermined degree, to permit, via said control unit, said two-way valve to take the position to introduce the air into said secondary main fuel supply line.
References Cited (Backward Citations)
US4050428A
Cited
US4192140A
Cited
US4057042A
Cited
US4106464A
Cited
JPS54155311A
Cited
US4282840A
Cited
US4341190A
Cited
USPTO Annuity & Maintenance Windows
| Annuity Stage | Window Opens | Payment Deadline | Surcharge Period Until | Estimated Fee | Status |
|---|---|---|---|---|---|
| 3.5 Years (Year 4) | 1986-10-03 | 1987-04-04 | 1987-10-04 | $2000.00 | Window Closed / Lapsed |
| 7.5 Years (Year 8) | 1990-10-03 | 1991-04-04 | 1991-10-04 | $3760.00 | Window Closed / Lapsed |
| 11.5 Years (Year 12) | 1994-10-03 | 1995-04-04 | 1995-10-04 | $7700.00 | Window Closed / Lapsed |