Patent US4376427A successfully refreshed from Google Patents.
US4376427A
Expired / Lapsed
US
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Engine air/fuel ratio control system with both normal idling and idle up idling capability
Assignee: Toyota Motor Corp
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Filing: 1981-11-13
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Granted: 1983-03-15
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Expires: 2001-11-13
Abstract
Abstract An engine includes a three way catalytic converter in its exhaust system, and a carburetor whose throttle valve has a normal and an idle up idling position, selected between by an idle up device. A device for weakening the air/fuel ratio of the mixture in the engine intake system only functions when no oxygen is detected in the engine exhaust system by an oxygen sensor. A means for supplying enough secondary air into the exhaust system upstream of the oxygen sensor to make the exhaust gases leaner than stoichiometric functions according to supply of a controlling vacuum. A first vacuum take out port is provided in the throat of the carburetor at a position downstream of the throttle valve when it is in the normal idling position and upstream of it when it is opened a little from the normal idling position. A second vacuum take out port is provided in the throat at a position downstream of the throttle valve when it is in the idle up idling position and upstream of it when it is opened a little from the idle up idling position. A vacuum switching system supplies vacuum from either the first or second take out port to the secondary air supplying means as controlling vacuum, according as idle up is being not performed, or is being performed, respectively.
Inventors
- 👤 Kisaburo Mizuno
Bibliographic Details
Application Number
—
Jurisdiction
US
Data Source
google_patents
Last Synchronized
2026-10-29 22:40
CPC Classifications
F; F01; F01N; F01N3/00; F01N3/08; F01N3/10; F01N3/18; F01N3/22; F01N3/222; F01N3/227; F02; F02D; F02D31/00; F02D31/001; F02D31/002; F02D31/003; F02D31/004; F02D35/00; F02M; F02M3/00; F02M3/06; F02M3/07
Claims Analysis
Total Claims: 14
Claim 1
Independent Claim
435 words
For an internal combustion engine comprising an exhaust system and a fuel intake passage system comprising a carburetor which comprises an intake throat, a throttle valve mounted in said intake throat, and an idle up device which selectively acts on said throttle valve so as to control its most closed position to be either a first idling position near its fully closed position or a second idle up idling position slightly more open that said first idling position; said carburetor in its basic operational mode tending to deliver an air/fuel mixture richer than stoichiometric: an air/fuel ratio control system, comprising: (a) an oxygen sensor for detecting the concentration of oxygen in the exhaust gases in said exhaust system; (b) a means for adjusting the air/fuel ratio of the air/fuel mixture being supplied to the engine through said fuel intake passage system towards the leaner, which receives the signal from said oxygen sensor, and which functions only when said sensor is detecting no oxygen in the exhaust gases in said exhaust system; (c) a means for supplying a flow of secondary air into said exhaust system during idling engine operation, upstream of said oxygen sensor, in a flow amount sufficient to render the exhaust gases in said exhaust system leaner than stoichiometric, said means thus supplying secondary air when and only when it receives supply of a controlling vacuum; (d) a first vacuum takeout port formed at a point in said intake throat which is downstream of said throttle valve when said throttle valve is in said first idling position but which is upstream of said throttle valve when said throttle valve is opened a slight amount from said first idling position; (e) a second vacuum takeout port formed at a point in said intake throat which is downstream of said throttle valve when said throttle valve is in said second idle up idling position but which is upstream of said throttle valve when said throttle valve is opened a slight amount from said second idle up idling position; and (f) a vacuum switching system, which provides supply of vacuum from said first vacuum take out port to said means for supplying secondary air as said controlling vacuum when said idle up device is controlling the most closed position of said throttle valve to be said first idling position, and which provides supply of vacuum from said second vacuum take out port to said means for supplying secondary air as said controlling vacuum when said idle up device is controlling the most closed position of said throttle valve to be said second idle up idling position.
Claim 2
Dependent Claim
435 words
For an internal combustion engine comprising an exhaust system and a fuel intake passage system comprising a carburetor which comprises an intake throat, a throttle valve mounted in said intake throat, and an idle up device which selectively acts on said throttle valve so as to control its most closed position to be either a first idling position near its fully closed position or a second idle up idling position slightly more open that said first idling position; said carburetor in its basic operational mode tending to deliver an air/fuel mixture richer than stoichiometric: an air/fuel ratio control system, comprising: (a) an oxygen sensor for detecting the concentration of oxygen in the exhaust gases in said exhaust system; (b) a means for adjusting the air/fuel ratio of the air/fuel mixture being supplied to the engine through said fuel intake passage system towards the leaner, which receives the signal from said oxygen sensor, and which functions only when said sensor is detecting no oxygen in the exhaust gases in said exhaust system; (c) a means for supplying a flow of secondary air into said exhaust system during idling engine operation, upstream of said oxygen sensor, in a flow amount sufficient to render the exhaust gases in said exhaust system leaner than stoichiometric, said means thus supplying secondary air when and only when it receives supply of a controlling vacuum; (d) a first vacuum takeout port formed at a point in said intake throat which is downstream of said throttle valve when said throttle valve is in said first idling position but which is upstream of said throttle valve when said throttle valve is opened a slight amount from said first idling position; (e) a second vacuum takeout port formed at a point in said intake throat which is downstream of said throttle valve when said throttle valve is in said second idle up idling position but which is upstream of said throttle valve when said throttle valve is opened a slight amount from said second idle up idling position; and (f) a vacuum switching system, which provides supply of vacuum from said first vacuum take out port to said means for supplying secondary air as said controlling vacuum when said idle up device is controlling the most closed position of said throttle valve to be said first idling position, and which provides supply of vacuum from said second vacuum take out port to said means for supplying secondary air as said controlling vacuum when said idle up device is controlling the most closed position of said throttle valve to be said second idle up idling position.
Claim 3
Dependent Claim
46 words
An air/fuel ratio control system according to claim 1, wherein said means for adjusting the air/fuel ratio of the air/fuel mixture being supplied to the engine through said fuel intake passage system towards the leaner injects air into said intake passage system downstream of said carburetor.
Claim 4
Dependent Claim
288 words
An air/fuel ratio control system according to claim 2, for an internal combustion engine wherein said idle up device comprises a vacuum actuator which when supplied with vacuum moves a stop against which said throttle valve abuts in its idling position in the direction of increasing idling speed, and an electric control device which despatches an electrical signal when idle up is to be performed: wherein said vacuum switching system comprises an electromagnetic switching valve with a first, a second, and a third port, a one way valve, a vacuum conduit, and a throttling element; said second and said third ports of said electromagnetic switching valve being communicated together when said electromagnetic switching valve is not supplied with actuating electrical energy, and said first and said second ports of said electromagnetic switching valve being communicated together when said electromagnetic switching valve is supplied with actuating electrical energy; said electromagnetic switching valve being supplied with said electrical signal as supply of actuating electrical energy; said third port of said electromagnetic switching valve being communicated to atmosphere; said first port of said electromagnetic switching valve being communicated to said second vacuum take out port; and said second port of said electromagnetic switching valve being communicated to said vacuum actuator of said idle up device and also being communicated via said one way valve against its direction of transmitting fluid to a first end of said conduit, the other end of said conduit being communicated to said means for supplying a flow of secondary air into said exhaust system during idling engine operation so as to supply said controlling vacuum thereto; an intermediate part of said conduit also being communicated via said throttling element to said first vacuum take out port.
Claim 5
Dependent Claim
229 words
An air/fuel ratio control system according to claim 2, for an internal combustion engine wherein said idle up device comprises an electric actuator which when supplied with actuating electrical energy moves a stop against which said throttle valve abuts in its idling position in the direction of increasing idling speed, and an electric control device which despatches an electrical signal to said electric actuator when idle up is to be performed: wherein said vacuum switching system comprises an electromagnetic switching valve with a first, a second, and a third port; said second and said third ports of said electromagnetic switching valve being communicated together when said electromagnetic switching valve is not supplied with actuating electrical energy, and said first and said second ports of said electromagnetic switching valve being communicated together when said electromagnetic switching valve is supplied with actuating electrical energy; said electromagnetic switching valve being supplied with said electrical signal as supply of actuating electrical energy; said third port of said electromagnetic switching valve being communicated to said first vacuum take out port; said first port of said electromagnetic switching valve being communicated to said second vacuum take out port; and said second port of said electromagnetic switching valve being communicated to said means for supplying a flow of secondary air into said exhaust system during idling engine operation so as to supply said controlling vacuum thereto.
Claim 6
Dependent Claim
53 words
An air/fuel ratio control system according to claim 1, said carburetor being formed with an auxiliary air bleed passage, wherein said means for adjusting the air/fuel ratio of the air/fuel mixture being supplied to the engine through said fuel intake passage system towards the leaner injects air into said auxiliary air bleed passage.
Claim 7
Dependent Claim
288 words
An air/fuel ratio control system according to claim 5, for an internal combustion engine wherein said idle up device comprises a vacuum actuator which when supplied with vacuum moves a stop against which said throttle valve abuts in its idling position in the direction of increasing idling speed, and an electric control device which despatches an electrical signal when idle up is to be performed: wherein said vacuum switching system comprises an electromagnetic switching valve with a first, a second, and a third port, a one way valve, a vacuum conduit, and a throttling element; said second and said third ports of said electromagnetic switching valve being communicated together when said electromagnetic switching valve is not supplied with actuating electrical energy, and said first and said second ports of said electromagnetic switching valve being communicated together when said electromagnetic switching valve is supplied with actuating electrical energy; said electromagnetic switching valve being supplied with said electrical signal as supply of actuating electrical energy; said third port of said electromagnetic switching valve being communicated to atmosphere; said first port of said electromagnetic switching valve being communicated to said second vacuum take out port; and said second port of said electromagnetic switching valve being communicated to said vacuum actuator of said idle up device and also being communicated via said one way valve against its direction of transmitting fluid to a first end of said conduit, the other end of said conduit being communicated to said means for supplying a flow of secondary air into said exhaust system during idling engine operation so as to supply said controlling vacuum thereto; an intermediate part of said conduit also being communicated via said throttling element to said first vacuum take out port.
Claim 8
Dependent Claim
229 words
An air/fuel ratio control system according to claim 5, for an internal combustion engine wherein said idle up device comprises an electric actuator which when supplied with actuating electrical energy moves a stop against which said throttle valve abuts in its idling position in the direction of increasing idling speed, and an electric control device which despatches an electrical signal to said electric actuator when idle up is to be performed: wherein said vacuum switching system comprises an electromagnetic switching valve with a first, a second, and a third port; said second and said third ports of said electromagnetic switching valve being communicated together when said electromagnetic switching valve is not supplied with actuating electrical energy, and said first and said second ports of said electromagnetic switching valve being communicated together when said electromagnetic switching valve is supplied with actuating electrical energy; said electromagnetic switching valve being supplied with said electrical signal as supply of actuating electrical energy; said third port of said electromagnetic switching valve being communicated to said first vacuum take out port; said first port of said electromagnetic switching valve being communicated to said second vacuum take out port; and said second port of said electromagnetic switching valve being communicated to said means for supplying a flow of secondary air into said exhaust system during idling engine operation so as to supply said controlling vacuum thereto.
Claim 9
Dependent Claim
46 words
An air/fuel ratio control system according to any one of the previous claims, wherein said means for supplying a flow of secondary air into said exhaust system comprises a vacuum actuated valve which controls flow of atmospheric air into a port formed in said exhaust system.
Claim 10
Dependent Claim
73 words
An air/fuel ratio control system according to claim 8, wherein said vacuum actuated valve comprises a valve port, a valve element, and a vacuum actuator, said controlling vacuum being supplied to said vacuum actuator, and said valve element being drivingly coupled to said vacuum actuator so as to be selectively driven against said valve port or withdrawn from said valve port, according respectively as said controlling vacuum is not present, or is present.
Claim 11
Dependent Claim
56 words
An air/fuel ratio control system according to claim 9, wherein said means for supplying a flow of secondary air into said exhaust system further comprises a one way air valve in series with said vacuum actuated valve, said one way valve only allowing flow of air into said exhaust system, and not in the reverse direction.
Claim 12
Dependent Claim
19 words
An air/fuel ratio control system according to claim 10, wherein said one way air valve is a reed valve.
Claim 13
Dependent Claim
56 words
An air/fuel ratio control system according to claim 8, wherein said means for supplying a flow of secondary air into said exhaust system further comprises a one way air valve in series with said vacuum actuated valve, said one way valve only allowing flow of air into said exhaust system, and not in the reverse direction.
Claim 14
Dependent Claim
19 words
An air/fuel ratio control system according to claim 12, wherein said one way air valve is a reed valve.
References Cited (Backward Citations)
USPTO Annuity & Maintenance Windows
| Annuity Stage | Window Opens | Payment Deadline | Surcharge Period Until | Estimated Fee | Status |
|---|---|---|---|---|---|
| 3.5 Years (Year 4) | 1986-03-14 | 1986-09-13 | 1987-03-15 | $2000.00 | Window Closed / Lapsed |
| 7.5 Years (Year 8) | 1990-03-14 | 1990-09-13 | 1991-03-15 | $3760.00 | Window Closed / Lapsed |
| 11.5 Years (Year 12) | 1994-03-14 | 1994-09-13 | 1995-03-15 | $7700.00 | Window Closed / Lapsed |