US6205785B1
Expired / Lapsed
US
⏱️ 0.0 years remaining
Exhaust gas recirculation system
Assignee: Caterpillar Inc
•
Filing: 1999-07-21
•
Granted: 2001-03-27
•
Expires: 2019-07-21
Abstract
Abstract A system and method for exhaust gas recirculation (EGR) in a heavy-duty diesel engine is disclosed. The disclosed EGR system comprises an EGR conduit, an EGR valve, an EGR cooler, and an EGR driver such as an auxiliary compressor driven by the exhaust gas driven turbine of the engine to forcibly drive the recirculated exhaust gas from the exhaust manifold via an EGR conduit to the intake manifold when the EGR valve is open. The disclosed EGR system also includes an EGR bypass conduit, the flow through which is governed by an electronically controlled EGR bypass valve. The EGR system also includes an ECM that controls the EGR bypass valve such that a flow of exhaust gas is directed through the EGR conduit and EGR driver during selected engine operating conditions where the primary EGR valve is open (i.e. EGR is on) and directs a flow of air from the intake through the EGR bypass conduit and EGR driver when EGR valve is closed (i.e. EGR is off). In addition, the ECM optionally controls the EGR bypass valve such that a flow of exhaust gas from the exhaust manifold is directed through the EGR bypass conduit to the intake manifold when the exhaust manifold pressure is greater than the intake manifold pressure.
Inventors
- 👤 Gerald N. Coleman
Bibliographic Details
Application Number
—
Jurisdiction
US
Data Source
google_patents
Last Synchronized
2026-10-27 18:41
CPC Classifications
F; F02; F02B; F02B37/00; F02B37/005; F01; F01N; F01N13/00; F01N13/08; F01N13/10; F01N13/107; F02B37/12; F02B37/24; F02D; F02D21/00; F02D21/06; F02D21/08; F02M; F02M26/00; F02M26/02; F02M26/04; F02M26/05; F02M26/13; F02M26/34; F02M26/38; F02M26/08; F02M26/09; F02M26/10; F02M26/22; F02M26/23; F02M26/27; F02M26/28; F02M26/42; Y; Y02; Y02T; Y02T10/00; Y02T10/10; Y02T10/12
Claims Analysis
Total Claims: 21
Claim 1
Independent Claim
106 words
An exhaust gas recirculation system for an internal combustion engine comprising: an exhaust gas recirculation primary conduit fluidically coupling an exhaust manifold with an intake manifold; an exhaust gas recirculation valve disposed along said exhaust gas recirculation primary conduit proximate said exhaust manifold; an exhaust gas recirculation driver disposed along said exhaust gas recirculation conduit and adapted for forcibly driving said recirculated exhaust gas to said intake manifold; an exhaust gas recirculation bypass conduit in fluidic communication with said exhaust gas recirculation primary conduit while circumventing said exhaust gas recirculation driver; and an exhaust gas recirculation bypass valve disposed along said exhaust gas recirculation bypass conduit.
Claim 2
Dependent Claim
106 words
An exhaust gas recirculation system for an internal combustion engine comprising: an exhaust gas recirculation primary conduit fluidically coupling an exhaust manifold with an intake manifold; an exhaust gas recirculation valve disposed along said exhaust gas recirculation primary conduit proximate said exhaust manifold; an exhaust gas recirculation driver disposed along said exhaust gas recirculation conduit and adapted for forcibly driving said recirculated exhaust gas to said intake manifold; an exhaust gas recirculation bypass conduit in fluidic communication with said exhaust gas recirculation primary conduit while circumventing said exhaust gas recirculation driver; and an exhaust gas recirculation bypass valve disposed along said exhaust gas recirculation bypass conduit.
Claim 3
Dependent Claim
24 words
The exhaust gas recirculation system of claim 1 wherein said exhaust gas recirculation driver is a compressor driven by an exhaust gas driven turbine.
Claim 4
Dependent Claim
24 words
The exhaust gas recirculation system of claim 1 wherein said exhaust gas recirculation driver is a blower driven by a crankshaft of said engine.
Claim 5
Dependent Claim
72 words
The exhaust gas recirculation system of claim 1 further comprising an engine control module adapted to control flows through said exhaust gas recirculation system in response to various engine operating conditions; and wherein said exhaust gas recirculation bypass valve is an electronically controlled valve having a first position that allows flow through said exhaust gas recirculation bypass conduit and a second position that restricts flow through said exhaust gas recirculation bypass conduit.
Claim 6
Dependent Claim
29 words
The exhaust gas recirculation system of claim 4 wherein said exhaust gas recirculation bypass valve is oriented in said first position when said exhaust gas recirculation valve is shut.
Claim 7
Dependent Claim
37 words
The exhaust gas recirculation system of claim 4 wherein said exhaust gas recirculation bypass valve is oriented in said first position when the pressure in said exhaust manifold is greater than the pressure in said intake manifold.
Claim 8
Dependent Claim
38 words
The exhaust gas recirculation system of claim 1 wherein said exhaust gas recirculation bypass valve is a pressure relief valve that opens when the pressure in said exhaust manifold is greater than the pressure in said intake manifold.
Claim 9
Dependent Claim
108 words
In an exhaust gas recirculation system for an engine having an intake manifold, an exhaust manifold, an exhaust gas recirculation conduit, an exhaust gas recirculation cooler, an exhaust gas recirculation valve, and an exhaust gas recirculation driver, an improvement to said exhaust gas recirculation system comprising: an exhaust gas recirculation bypass conduit in flow communication with said exhaust gas recirculation conduit at a first location upstream of said exhaust gas recirculation driver and a second location downstream of said exhaust gas recirculation driver; and an exhaust gas recirculation bypass valve disposed along said exhaust gas recirculation bypass conduit for controlling flow through said exhaust gas recirculation bypass conduit.
Claim 10
Dependent Claim
108 words
In an exhaust gas recirculation system for an engine having an intake manifold, an exhaust manifold, an exhaust gas recirculation conduit, an exhaust gas recirculation cooler, an exhaust gas recirculation valve, and an exhaust gas recirculation driver, an improvement to said exhaust gas recirculation system comprising: an exhaust gas recirculation bypass conduit in flow communication with said exhaust gas recirculation conduit at a first location upstream of said exhaust gas recirculation driver and a second location downstream of said exhaust gas recirculation driver; and an exhaust gas recirculation bypass valve disposed along said exhaust gas recirculation bypass conduit for controlling flow through said exhaust gas recirculation bypass conduit.
Claim 11
Dependent Claim
21 words
The improvement of claim 8 wherein said exhaust gas recirculation driver is a compressor driven by an exhaust gas driven turbine.
Claim 12
Dependent Claim
21 words
The improvement of claim 8 wherein said exhaust gas recirculation driver is a blower driven by a crankshaft of said engine.
Claim 13
Dependent Claim
69 words
The improvement of claim 8 further comprising an engine control module adapted to control flows through said exhaust gas recirculation system in response to various engine operating conditions and wherein said exhaust gas recirculation bypass valve is an electronically controlled valve having a first position that allows flow through said exhaust gas recirculation bypass conduit and a second position that restricts flow through said exhaust gas recirculation bypass conduit.
Claim 14
Dependent Claim
26 words
The improvement of claim 11 wherein said exhaust gas recirculation bypass valve is oriented in said first position when said exhaust gas recirculation valve is shut.
Claim 15
Dependent Claim
34 words
The improvement of claim 11 wherein said exhaust gas recirculation bypass valve is oriented in said first position when the pressure in said exhaust manifold is greater than the pressure in said intake manifold.
Claim 16
Dependent Claim
35 words
The improvement of claim 8 wherein said exhaust gas recirculation bypass valve is pressure relief valve that is open when the pressure in said exhaust manifold is greater than the pressure in said intake manifold.
Claim 17
Independent Claim
163 words
A method of controlling an exhaust gas recirculation system of an internal combustion engine having an intake manifold, an exhaust manifold, an exhaust gas recirculation conduit, an exhaust gas recirculation valve, and an exhaust gas recirculation driver, said method comprising the steps of: directing a flow of exhaust gas through said exhaust gas recirculation conduit and said exhaust gas recirculation driver at a first set of engine operating conditions when said exhaust gas is recirculated from said exhaust manifold to said intake manifold; and directing a bypass flow through an exhaust gas recirculation bypass conduit and said exhaust gas recirculation driver at a second set of engine operating conditions when said exhaust gas is not recirculating from said exhaust manifold to said intake manifold, said exhaust gas recirculation bypass conduit being disposed in flow communication with said exhaust gas recirculation conduit at a first location upstream of said exhaust gas recirculation driver and a second location downstream of said exhaust gas recirculation driver.
Claim 18
Independent Claim
163 words
A method of controlling an exhaust gas recirculation system of an internal combustion engine having an intake manifold, an exhaust manifold, an exhaust gas recirculation conduit, an exhaust gas recirculation valve, and an exhaust gas recirculation driver, said method comprising the steps of: directing a flow of exhaust gas through said exhaust gas recirculation conduit and said exhaust gas recirculation driver at a first set of engine operating conditions when said exhaust gas is recirculated from said exhaust manifold to said intake manifold; and directing a bypass flow through an exhaust gas recirculation bypass conduit and said exhaust gas recirculation driver at a second set of engine operating conditions when said exhaust gas is not recirculating from said exhaust manifold to said intake manifold, said exhaust gas recirculation bypass conduit being disposed in flow communication with said exhaust gas recirculation conduit at a first location upstream of said exhaust gas recirculation driver and a second location downstream of said exhaust gas recirculation driver.
Claim 19
Dependent Claim
26 words
The method of claim 15 wherein said first set of engine operating conditions corresponds to engine operating conditions where said exhaust gas recirculation valve is open.
Claim 20
Dependent Claim
26 words
The method of claim 15 wherein said second set of engine operating conditions corresponds to engine operating conditions where said exhaust gas recirculation valve is closed.
Claim 21
Dependent Claim
43 words
The method of claim 15 further comprising the step of directing a flow of exhaust gas from said exhaust manifold through said exhaust gas recirculation bypass conduit to said intake manifold when said exhaust manifold pressure is greater than said intake manifold pressure.
References Cited (Backward Citations)
GB941532A
Cited
SU428103A1
Cited
US4215550A
Cited
US4426848A
Cited
JPH0450433A
Cited
JPH0571426A
Cited
JPH05180089A
Cited
DE4231218C1
Cited
US5406796A
Cited
US5657630A
Cited
US5611202A
Cited
US5564275A
Cited
US5791146A
Cited
US5794445A
Cited
WO1998039563A1
Cited
US5771868A
Cited
EP0889226A2
Cited
USPTO Annuity & Maintenance Windows
| Annuity Stage | Window Opens | Payment Deadline | Surcharge Period Until | Estimated Fee | Status |
|---|---|---|---|---|---|
| 3.5 Years (Year 4) | 2004-03-26 | 2004-09-25 | 2005-03-27 | $2000.00 | Window Closed / Lapsed |
| 7.5 Years (Year 8) | 2008-03-26 | 2008-09-25 | 2009-03-27 | $3760.00 | Window Closed / Lapsed |
| 11.5 Years (Year 12) | 2012-03-26 | 2012-09-25 | 2013-03-27 | $7700.00 | Window Closed / Lapsed |