Patent US5353776A successfully refreshed from Google Patents.
US5353776A
Expired / Lapsed
US
⏱️ 0.0 years remaining
Method and apparatus for controlling fuel flow to lean burn engines
Assignee: Southwest Research Institute
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Filing: 1993-03-22
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Granted: 1994-10-11
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Expires: 2013-03-22
Abstract
Abstract The system for controlling the air/fuel mixture introduced into a lean burn engines includes a fuel/air mixing carburetor that is connected to the intake conduit to the engine and an air by-pass conduit that is also connected to the intake conduit. The main throttle valve is located downstream of the connection between the carburation conduit and the by-pass conduit so that mixing of the carbureted fuel/air mixture with the by-pass air occurs upstream of the main throttle valve. Accordingly, the main throttle valve does not control the air/fuel ratio but rather controls the quantity of fuel being introduced into the engine. The by-pass throttle valve may be controlled by an oxygen sensor in the exhaust system or by a fuel sensor in the intake system, when operating on natural gas, gasoline, hydrogen or alcohol fuel, as desired.
Inventors
- 👤 Robert W. Burrahm
- 👤 David P. Meyers
Bibliographic Details
Application Number
—
Jurisdiction
US
Data Source
google_patents
Last Synchronized
2026-11-02 23:17
CPC Classifications
F; F02; F02D; F02D9/00; F02D9/02; F02D35/00; F02D35/0015; F02D35/0046; F02D35/0053; F02M; F02M23/00; F02M23/04; F02D2009/0201; F02D2009/0272; Y; Y02; Y02T; Y02T10/00; Y02T10/10; Y02T10/12
Claims Analysis
Total Claims: 14
Claim 1
Independent Claim
178 words
A fuel control system for lean burn engines having intake and exhaust manifolds comprising: a carburetor for mixing fuel and air; an intake conduit connecting the carburetor with the intake manifold; an air by-pass conduit connected with said intake conduit; a by-pass throttle valve located in said by-pass conduit for controlling the air flow through said by-pass conduit to said intake conduit; a main throttle valve located in said intake conduit between the connection of said by-pass conduit with said intake conduit and said intake manifold for controlling the air/fuel mixture from said intake conduit and by-pass conduit into said engine; first control means for changing the position of said main throttle valve to vary the quantity of the mixture supplied to said engine; second control means for changing the position of said by-pass throttle valve to change the ratio of the mixture supplied to said engine independent from the position of said main throttle valve, and wherein the position of said by-pass throttle valve remains essentially unaffected by changes in the position of the main throttle valve.
Claim 2
Dependent Claim
178 words
A fuel control system for lean burn engines having intake and exhaust manifolds comprising: a carburetor for mixing fuel and air; an intake conduit connecting the carburetor with the intake manifold; an air by-pass conduit connected with said intake conduit; a by-pass throttle valve located in said by-pass conduit for controlling the air flow through said by-pass conduit to said intake conduit; a main throttle valve located in said intake conduit between the connection of said by-pass conduit with said intake conduit and said intake manifold for controlling the air/fuel mixture from said intake conduit and by-pass conduit into said engine; first control means for changing the position of said main throttle valve to vary the quantity of the mixture supplied to said engine; second control means for changing the position of said by-pass throttle valve to change the ratio of the mixture supplied to said engine independent from the position of said main throttle valve, and wherein the position of said by-pass throttle valve remains essentially unaffected by changes in the position of the main throttle valve.
Claim 3
Dependent Claim
59 words
The fuel control system of claim 1 wherein said control means includes: a sensor responsive to an engine operating characteristic for transmitting a first signal representative of such characteristic; and a valve actuator connected with said by-pass throttle valve arranged to be responsive to said first signal for positioning said by-pass throttle valve in accordance with said first signal.
Claim 4
Dependent Claim
65 words
The system of claim 2 and also including means for receiving said first signal, comparing said first signal to an input signal representative of a desired air/fuel mixture based on said engine operating characteristic and transmitting an output signal representative of the difference between said first signal and said input signal to said valve actuator to provide more or less air through said by-pass conduit.
Claim 5
Dependent Claim
23 words
The system of claim 3 wherein said sensor is located to sense the fuel content in said air/fuel mixture supplied to said engine.
Claim 6
Dependent Claim
49 words
The fuel control system of claim 1 further comprising a sensor in the intake manifold to sense the fuel content of the air/fuel mixture being supplied to said engine; and said second control means changing the position of said by-pass throttle valve in response to said sensed fuel content.
Claim 7
Independent Claim
223 words
A method for controlling the air/fuel ratio in a lean burn engine having an intake conduit connected with an intake manifold and a main throttle valve located in said intake conduit comprising the steps of: mixing air and fuel to form an air/fuel mixture for burning in the engine; supplying additional air through a by-pass conduit having a by-pass throttle valve into said mixture prior to introduction of said mixture into said engine to form a lean air/fuel mixture; controlling the volume of said lean air/fuel mixture to be supplied to said engine by positioning said main throttle valve; sensing the fuel content of said lean air/fuel mixture in said intake manifold; introducing said lean air/fuel mixture into said engine through said main throttle valve and said intake manifold; comparing an input signal representative of the desired fuel content of the air/fuel mixture to the signal representative of said sensed fuel content; and transmitting an output signal representative of the difference between said input signal and said signal representative of said sensed fuel content to said by-pass throttle valve in said by-pass conduit to position said by-pass throttle valve in accordance with the desired fuel content as represented by said input signal whereby the position of said by-pass throttle valve remains essentially unaffected by changes in the position of said main throttle valve.
Claim 8
Independent Claim
223 words
A method for controlling the air/fuel ratio in a lean burn engine having an intake conduit connected with an intake manifold and a main throttle valve located in said intake conduit comprising the steps of: mixing air and fuel to form an air/fuel mixture for burning in the engine; supplying additional air through a by-pass conduit having a by-pass throttle valve into said mixture prior to introduction of said mixture into said engine to form a lean air/fuel mixture; controlling the volume of said lean air/fuel mixture to be supplied to said engine by positioning said main throttle valve; sensing the fuel content of said lean air/fuel mixture in said intake manifold; introducing said lean air/fuel mixture into said engine through said main throttle valve and said intake manifold; comparing an input signal representative of the desired fuel content of the air/fuel mixture to the signal representative of said sensed fuel content; and transmitting an output signal representative of the difference between said input signal and said signal representative of said sensed fuel content to said by-pass throttle valve in said by-pass conduit to position said by-pass throttle valve in accordance with the desired fuel content as represented by said input signal whereby the position of said by-pass throttle valve remains essentially unaffected by changes in the position of said main throttle valve.
Claim 9
Dependent Claim
61 words
The method of claim 6 and also including the steps of: transmitting a signal representative of the CH 4 content to said by-pass throttle valve in said by-pass conduit; and changing the volume of additional air to vary the lean air/fuel mixture by positioning said by-pass throttle valve in response to said signal, if required, to maintain a predetermined air/fuel mixture.
Claim 10
Independent Claim
200 words
A method for controlling the air/fuel ratio in a lean burn engine having an intake conduit connected with an intake manifold and a main throttle valve located in said intake conduit comprising the steps of: mixing air and fuel to form an air/fuel mixture for burning in the engine; supplying additional air through a by-pass conduit having a by-pass throttle valve into said mixture prior to introduction of said mixture the said engine to form a lean air/fuel mixture; introducing said lean air/fuel mixture into the engine through said main throttle valve and said intake manifold; controlling the volume of said lean air/fuel mixture supplied to the engine by changing the position of said main throttle valve; sensing the O 2 content of exhaust gas from the engine; transmitting a signal representative of the O 2 content to said by-pass throttle valve located in said by-pass conduit; and changing the volume of said additional air to vary the lean air/fuel mixture by positioning said by-pass throttle valve in response to said representative signal to maintain a predetermined air/fuel mixture wherein the position of said by-pass throttle valve remains essentially unaffected by changes in the position of the main throttle valve.
Claim 11
Independent Claim
200 words
A method for controlling the air/fuel ratio in a lean burn engine having an intake conduit connected with an intake manifold and a main throttle valve located in said intake conduit comprising the steps of: mixing air and fuel to form an air/fuel mixture for burning in the engine; supplying additional air through a by-pass conduit having a by-pass throttle valve into said mixture prior to introduction of said mixture the said engine to form a lean air/fuel mixture; introducing said lean air/fuel mixture into the engine through said main throttle valve and said intake manifold; controlling the volume of said lean air/fuel mixture supplied to the engine by changing the position of said main throttle valve; sensing the O 2 content of exhaust gas from the engine; transmitting a signal representative of the O 2 content to said by-pass throttle valve located in said by-pass conduit; and changing the volume of said additional air to vary the lean air/fuel mixture by positioning said by-pass throttle valve in response to said representative signal to maintain a predetermined air/fuel mixture wherein the position of said by-pass throttle valve remains essentially unaffected by changes in the position of the main throttle valve.
Claim 12
Dependent Claim
100 words
The method of claim 8 and also including the steps of: comparing an input signal representative of the desired O 2 content of exhaust gas from the engine to the signal representative of the sensed O 2 content of the exhaust gas; and transmitting an output signal representative of the difference between said input signal and said signal representative of the sensed O 2 content of the exhaust gas to said by-pass throttle valve to position said by-pass throttle valve in accordance with the desired value of O 2 content in the exhaust gas as represented by said input signal.
Claim 13
Dependent Claim
206 words
A fuel control system for lean burn engines having intake and exhaust manifolds comprising: a carburetor for mixing fuel and air; an intake conduit connecting said carburetor with said intake manifold; an air by-pass conduit connected with said intake conduit; a by-pass throttle valve located in said air by-pass conduit for controlling the air-flow through said air by-pass conduit to said intake conduit; a main throttle valve located in said intake conduit between the connection of said air by-pass conduit with said intake conduit and said intake manifold for controlling the volume of said air/fuel fixture flowing from said intake conduit and said air by-pass conduit into said engine; a sensor in said intake manifold to sense the fuel content of the air/fuel mixture being supplied to said engine through said main throttle valve; a comparator having a set point corresponding to a desired air/fuel mixture; and means including said comparator for changing the position of said by-pass throttle valve to change the ratio of the mixture supplied to said engine to provide the desired air/fuel mixture independent from the position of said main throttle valve whereby the position of said by-pass valve remains essentially unaffected by changes in the position of said main throttle valve.
Claim 14
Dependent Claim
206 words
A fuel control system for lean burn engines having intake and exhaust manifolds comprising: a carburetor for mixing fuel and air; an intake conduit connecting said carburetor with said intake manifold; an air by-pass conduit connected with said intake conduit; a by-pass throttle valve located in said air by-pass conduit for controlling the air-flow through said air by-pass conduit to said intake conduit; a main throttle valve located in said intake conduit between the connection of said air by-pass conduit with said intake conduit and said intake manifold for controlling the volume of said air/fuel fixture flowing from said intake conduit and said air by-pass conduit into said engine; a sensor in said intake manifold to sense the fuel content of the air/fuel mixture being supplied to said engine through said main throttle valve; a comparator having a set point corresponding to a desired air/fuel mixture; and means including said comparator for changing the position of said by-pass throttle valve to change the ratio of the mixture supplied to said engine to provide the desired air/fuel mixture independent from the position of said main throttle valve whereby the position of said by-pass valve remains essentially unaffected by changes in the position of said main throttle valve.
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USPTO Annuity & Maintenance Windows
| Annuity Stage | Window Opens | Payment Deadline | Surcharge Period Until | Estimated Fee | Status |
|---|---|---|---|---|---|
| 3.5 Years (Year 4) | 1997-10-10 | 1998-04-11 | 1998-10-11 | $2000.00 | Window Closed / Lapsed |
| 7.5 Years (Year 8) | 2001-10-10 | 2002-04-11 | 2002-10-11 | $3760.00 | Window Closed / Lapsed |
| 11.5 Years (Year 12) | 2005-10-10 | 2006-04-11 | 2006-10-11 | $7700.00 | Window Closed / Lapsed |