EP1167727A2
Expired / Lapsed
EP
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Internal combustion engine and method for recirculating exhaust gas
Assignee: Toyota Motor Corp
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Filing: 2001-06-18
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Granted: —
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Expires: 2021-06-18
Abstract
Abstract An internal combustion engine performs a second mode of combustion where the EGR is less than the EGR gas that peaks the production of soot. The engine then performs a first mode of combustion where the EGR is greater than the EGR that peaks the production of soot. During the second mode, the engine curbs hydrocarbon supplied to an exhaust gas control catalyst by performing a combustion where hydrocarbon does not increase. The exhaust gas temperature discharged becomes relatively high and the EGR rate is set to zero. The engine then increases the hydrocarbon supplied to the catalyst by performing a combustion that increases the hydrocarbon. The temperature of exhaust gas discharged becomes relatively high, and the EGR rate is gradually increased. Accordingly, the engine quickly warms up the catalyst while preventing problems that occur, like clogging of an exhaust gas recirculation passage.
Inventors
- 👤 Shizuo Sasaki
- 👤 Kouji Yoshizaki
- 👤 Masato Gotoh
- 👤 Takekazu Ito
Bibliographic Details
Application Number
—
Jurisdiction
EP
Data Source
google_patents
Last Synchronized
2026-11-07 21:17
CPC Classifications
F; F02; F02D; F02D41/00; F02D41/02; F02D41/021; F02D41/0235; F02D41/024; F02D41/0255; F01; F01N; F01N3/00; F01N3/08; F01N3/10; F01N3/18; F01N3/20; F01N3/2006; F02D41/0025; F02D41/0047; F02D41/005; F02D41/0057; F02M; F02M26/00; F02M26/13; F02M26/35; F02M26/02; F02M26/04; F02M26/05; F02M26/09; F02M26/10; F02M26/22; F02M26/23; F02M26/33; Y; Y02; Y02T; Y02T10/00; Y02T10/10; Y02T10/12; Y02T10/40
Claims Analysis
Total Claims: 8
Claim 1
Independent Claim
324 words
An internal combustion engine having an exhaust gas recirculation
passage (24) for recirculating an exhaust gas discharged from a combustion chamber
into an engine intake passage (11), wherein as an amount of a recirculating exhaust
gas (EGR) supplied into the combustion chamber is increased, an amount of a soot
produced gradually increases and peaks, and as the amount of the EGR supplied into
the combustion chamber is further increased, a temperature of a fuel and a
surrounding gas upon combustion in the combustion chamber becomes lower than a
temperature that allows the soot to be produced, so that substantially no soot is
produced, the internal combustion engine characterized by comprising: an exhaust gas control catalyst (22, 26a) that purifyies the exhaust gas
discharged from the combustion chamber; and a controller that, at engine start-up, first causes performance of a
second combustion in which the amount of the EGR supplied into the combustion
chamber is less than the amount of EGR that peaks the amount of the soot produced,
and then causes performance of a first combustion in which the amount of EGR
supplied into the combustion chamber is greater than the amount of EGR that peaks
the amount of the soot produced, and substantially no soot is produced, wherein when the second combustion is performed at the engine start-up,
the controller first curbs an amount of a hydrocarbon supplied to the exhaust gas
control catalyst (22, 26a) by causing performance of a combustion in which the
amount of the hydrocarbon in the exhaust gas does not increase and a temperature of
the exhaust gas discharged from the combustion chamber becomes relatively high, and
then the controller increases the amount of the hydrocarbon supplied to the exhaust
gas control catalyst (22, 26a) by causing performance of a combustion in which the
amount of the hydrocarbon in the exhaust gas increases and the temperature of the
exhaust gas discharged from the combustion chamber becomes relatively high.
Claim 2
Dependent Claim
121 words
The internal combustion engine according to claim 1, characterized in: that the exhaust gas control catalyst (26a) is a recirculation exhaust gas control
catalyst disposed in the exhaust gas recirculation passage; and that the controller sets the amount of the EGR to zero when causing
performance of the combustion in which the amount of the hydrocarbon in the exhaust
gas does not increase and the temperature of the exhaust gas discharged from the
combustion chamber becomes relatively high, and the controller gradually increases
the amount of the EGR when causing performance of the combustion in which the
amount of the hydrocarbon in the exhaust gas increases and the temperature of the
exhaust gas discharged from the combustion chamber becomes relatively high.
Claim 3
Dependent Claim
47 words
The internal combustion engine according to claim 2, characterized in
that the controller gradually increases the amount of the EGR from zero when the
temperature of the exhaust gas has reached a temperature that is sufficiently high to
warm up the recirculation exhaust gas control catalyst (26a).
Claim 4
Dependent Claim
20 words
The internal combustion engine according to claim 3, characterized in
that the amount of the EGR is increased in steps.
Claim 5
Dependent Claim
32 words
The internal combustion engine according to claim 2, characterized in
that when the recirculation exhaust gas control catalyst (26a) has been warmed up, the
second combustion is switched to the first combustion.
Claim 6
Dependent Claim
92 words
The internal combustion engine according to claim 1, characterized in
that when the second combustion is performed at the engine start-up, the controller
causes performance of a main fuel injection near a compression top dead center and an
additional fuel injection at a timing different from a timing of the main fuel injection,
and reduces an amount of an intake air to perform the combustion in which the
amount of the hydrocarbon in the exhaust gas increases and the temperature of the
exhaust gas discharged from the combustion chamber becomes relatively high.
Claim 7
Dependent Claim
259 words
An internal combustion engine having an exhaust gas recirculation
passage (24) for recirculating an exhaust gas discharged from a combustion chamber
into an engine intake passage (11), wherein as an amount of a recirculating exhaust
gas (EGR) supplied into the combustion chamber is increased, an amount of a soot
produced gradually increases and peaks, and as the amount of the EGR supplied into
the combustion chamber is further increased, a temperature of a fuel and a
surrounding gas upon combustion in the combustion chamber becomes lower than a
temperature that allows the soot to be produced, so that substantially no soot is
produced, the internal combustion engine characterized by comprising: an exhaust gas control catalyst (22, 26a) that purifies the exhaust gas
discharged from the combustion chamber; and a controller that varies an air-fuel ratio to decrease by changing a
degree of opening of a throttle valve so that the EGR rate increases during a low-load
operation of the engine, wherein the amount of soot produced from the engine starts increasing when
the EGR rate reaches a vicinity of a first predetermined amount, and the air-fuel ratio
becomes equal to about a second predetermined amount, and when the EGR rate is
further increased to reduce the air-fuel ratio, the amount of soot produced rapidly
increases and reaches its peak, and then the amount of soot sharply decreases and
becomes substantially zero when the EGR rate is controlled to be a third
predetermined amount, and the air-fuel ratio is reduced to be a fourth predetermined
amount, producing substantially no soot.
Claim 8
Independent Claim
306 words
A method of operating an internal combustion engine that uses an
exhaust gas recirculation passage (24) for recirculating an exhaust gas discharged
from a combustion chamber into an engine intake passage (11), wherein as an amount
of a recirculating exhaust gas (EGR) supplied into the combustion chamber is
increased, an amount of a soot produced gradually increases and peaks, and as the
amount of the EGR supplied into the combustion chamber is further increased, a
temperature of a fuel and a surrounding gas upon combustion in the combustion
chamber becomes lower than a temperature that allows the soot to be produced, so
that substantially no soot is produced, the method characterized by comprising the
steps of: purifying the exhaust gas that is discharged from the combustion
chamber; and performing a second combustion at engine start-up in which the
amount of the EGR supplied into the combustion chamber is less than the amount of
EGR that peaks the amount of the soot produced, and performing a first combustion in
which the amount of EGR supplied into the combustion chamber is greater than the
amount of EGR that peaks the amount of the soot produced, and substantially no soot
is produced, wherein, when the second combustion is performed at the engine start-up,
an amount of a hydrocarbon supplied to an exhaust gas control catalyst (22, 26a) is
curbed by performing a combustion in which the amount of the hydrocarbon in the
exhaust gas does not increase and a temperature of the exhaust gas discharged from
the combustion chamber becomes relatively high, and then the amount of the
hydrocarbon supplied to the exhaust gas control catalyst is increased by performing a
combustion in which the amount of the hydrocarbon in the exhaust gas increases and
the temperature of the exhaust gas discharged from the combustion chamber becomes
relatively high.
References Cited (Backward Citations)
JPH11166435A
Cited
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