US4055158A
Expired / Lapsed
US
⏱️ 0.0 years remaining
Exhaust recirculation
Assignee: Ethyl Corp
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Filing: 1976-03-19
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Granted: 1977-10-25
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Expires: 1996-03-19
Abstract
Abstract An improved internal combustion engine, exhaust gas recirculation (EGR) system is described which features the use of a liquid-cooled heat-exchange device to cool the recirculated exhaust before it is fed into the intake system of said engine. A preferred system uses a condensate trap situated downstream of said heat-exchange device. Use of this system effects further reduction in nitrogen oxides (NO x ) content of the exhaust.
Inventors
- 👤 Frederick J. Marsee
Bibliographic Details
Application Number
—
Jurisdiction
US
Data Source
google_patents
Last Synchronized
2026-10-28 05:50
CPC Classifications
F; F02; F02M; F02M26/00; F02M26/13; F02M26/35; F02M26/22; F02M26/23; F02M26/28; F02M26/29; F02M26/32; F02M26/50
Claims Analysis
Total Claims: 9
Claim 1
Independent Claim
213 words
In a spark ignited internal combustion engine having a carburetor type fuel/air induction system and an exhaust system, said engine having an exhaust recycle passage through which a portion of the exhaust gas is recycled from said exhaust system to said fuel/air induction system thereby lowering the nitrogen oxides content of the exhaust gas emitted by said engine, the improvement comprising a liquid-cooled heat exchanger in said exhaust recycle passage whereby exhaust gas flowing through said recycle passage passes through said heat exchanger and comes into heat exchange contact with the cooled surfaces within said liquid-cooled heat exchanger and is cooled below about 250° F, said heat exchanger comprising a heat exchanger housing through which said recycle exhaust gas passes and comes into heat exchange contact with a liquid-cooled surface, said housing having a drain opening at a low point, said drain opening being connected by a drain conduit to said exhaust system at a location downstream from where said exhaust recycle passage connects to said exhaust system, said recycle passage being connected to deliver cooled recycle exhaust to said fuel/air induction system downstream from the throttle plate of said carburetor whereby the nitrogen oxide content of said exhaust gas is lowered to an extent substantially greater than that obtained without said cooling.
Claim 2
Dependent Claim
213 words
In a spark ignited internal combustion engine having a carburetor type fuel/air induction system and an exhaust system, said engine having an exhaust recycle passage through which a portion of the exhaust gas is recycled from said exhaust system to said fuel/air induction system thereby lowering the nitrogen oxides content of the exhaust gas emitted by said engine, the improvement comprising a liquid-cooled heat exchanger in said exhaust recycle passage whereby exhaust gas flowing through said recycle passage passes through said heat exchanger and comes into heat exchange contact with the cooled surfaces within said liquid-cooled heat exchanger and is cooled below about 250° F, said heat exchanger comprising a heat exchanger housing through which said recycle exhaust gas passes and comes into heat exchange contact with a liquid-cooled surface, said housing having a drain opening at a low point, said drain opening being connected by a drain conduit to said exhaust system at a location downstream from where said exhaust recycle passage connects to said exhaust system, said recycle passage being connected to deliver cooled recycle exhaust to said fuel/air induction system downstream from the throttle plate of said carburetor whereby the nitrogen oxide content of said exhaust gas is lowered to an extent substantially greater than that obtained without said cooling.
Claim 3
Dependent Claim
13 words
The improvement of claim 1 wherein said liquid is circulating liquid engine coolant.
Claim 4
Dependent Claim
45 words
The improvement of claim 2 wherein said heat exchanger comprises a plurality of tubular conduits in parallel through which said liquid engine coolant circulates, the outer surface of said tubular conduits being in heat exchange contact with said exhaust gas flowing through said recycle passage.
Claim 5
Dependent Claim
40 words
The improvement of claim 2 wherein said heat exchanger comprises a plurality of tubular conduits in parallel forming part of said recycle passage, the outer surface of said tubular conduits being in heat exchange contact with said liquid engine coolant.
Claim 6
Dependent Claim
20 words
The improvement of claim 1 which additionally includes a filter in said exhaust recycle passage downstream from said heat exchanger.
Claim 7
Dependent Claim
227 words
In a spark ignited internal combustion engine having a carburetor type fuel/air induction system and an exhaust system, said engine having an exhaust recycle passage through which a portion of the exhaust gas is recycled from said exhaust system to said fuel/air induction system thereby lowering the nitrogen oxides content of the exhaust gas emitted by said engine, the improvement comprising a liquid-cooled heat exchanger in said exhaust recycle passage whereby exhaust gas flowing through said recycle passage passes through said heat exchanger and comes into heat exchange contact with the cooled surfaces within said liquid-cooled heat exchanger and is cooled below about 250° F, said exhaust recycle passage including a condensate trap, said trap comprising a housing having a recycle exhaust gas inlet and outlet, said trap being operatively connected in said exhaust recycle passage between said heat exchanger and said induction system, said housing having a drain opening at a low point, said drain opening being connected by a drain conduit to said exhaust system at a location downstream from where said exhaust recycle passage connects to said exhaust system, said recycle passage being connected to deliver cooled recycle exhaust to said fuel/air induction system downstream from the throttle plate of said carburetor whereby the nitrogen oxide content of said exhaust gas is lowered to an extent substantially greater than that obtained without said cooling.
Claim 8
Dependent Claim
227 words
In a spark ignited internal combustion engine having a carburetor type fuel/air induction system and an exhaust system, said engine having an exhaust recycle passage through which a portion of the exhaust gas is recycled from said exhaust system to said fuel/air induction system thereby lowering the nitrogen oxides content of the exhaust gas emitted by said engine, the improvement comprising a liquid-cooled heat exchanger in said exhaust recycle passage whereby exhaust gas flowing through said recycle passage passes through said heat exchanger and comes into heat exchange contact with the cooled surfaces within said liquid-cooled heat exchanger and is cooled below about 250° F, said exhaust recycle passage including a condensate trap, said trap comprising a housing having a recycle exhaust gas inlet and outlet, said trap being operatively connected in said exhaust recycle passage between said heat exchanger and said induction system, said housing having a drain opening at a low point, said drain opening being connected by a drain conduit to said exhaust system at a location downstream from where said exhaust recycle passage connects to said exhaust system, said recycle passage being connected to deliver cooled recycle exhaust to said fuel/air induction system downstream from the throttle plate of said carburetor whereby the nitrogen oxide content of said exhaust gas is lowered to an extent substantially greater than that obtained without said cooling.
Claim 9
Dependent Claim
20 words
The improvement of claim 6 which additionally includes a filter in said exhaust recycle passage downstream from said condensate trap.
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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) | 1980-10-24 | 1981-04-25 | 1981-10-25 | $2000.00 | Window Closed / Lapsed |
| 7.5 Years (Year 8) | 1984-10-24 | 1985-04-25 | 1985-10-25 | $3760.00 | Window Closed / Lapsed |
| 11.5 Years (Year 12) | 1988-10-24 | 1989-04-25 | 1989-10-25 | $7700.00 | Window Closed / Lapsed |