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EP0719937A2
Expired / Lapsed
EP
⏱️ 0.0 years remaining
Method of and system for purifying exhaust gas for vehicles
Assignee: Mazda Motor Corp
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Filing: 1995-12-22
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Granted: —
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Expires: 2015-12-22
Abstract
Abstract Exhaust gas temperature is raised after a cold engine start so as to rapidly activate a catalyst in an exhaust line by retarding an ignition timing at which an air-fuel mixture is fired in the engine to a point after top-dead-center during a certain time interval and promoting combustion of the air-fuel mixture, thereby accelerating the catalyst to attain its effective activation temperature after the cold engine start as quickly as possibly. <IMAGE>
Inventors
- 👤 Hirofumi Nishimura
- 👤 Tadataka Nakazumi
- 👤 Ken Umehara
- 👤 Takanobu Morimasa
- 👤 Masanori Misumi
Bibliographic Details
Application Number
—
Jurisdiction
EP
Data Source
google_patents
Last Synchronized
2026-10-29 19:47
CPC Classifications
F; F02; F02D; F02D41/00; F02D41/02; F02D41/021; F02D41/0235; F02D41/024; F02D41/0255; F02P; F02P5/00; F02P5/04; F02P5/145; F02P5/15; F02P5/1502; F02P5/1506; F02B; F02B2275/00; F02B2275/48; Y; Y02; Y02T; Y02T10/00; Y02T10/10; Y02T10/12; Y02T10/40
Claims Analysis
Total Claims: 19
Claim 1
Independent Claim
173 words
An exhaust gas purifying system having a catalytic converter in an exhaust line for purifying exhaust gas for a reciprocating internal combustion engine of a vehicle, said exhaust gas purifying system comprising: thermal condition monitoring means for monitoring a warmed condition of the engine; engine operation control means for controlling operation of the engine; combustion promoting means for promoting combustion of an air-fuel mixture in the engine; temperature control means for controlling a rise in exhaust gas temperature to an effective activation temperature of said catalytic converter during a time interval from an engine start, said temperature control means, while said thermal condition monitoring means detects a specified cold condition of the engine, causing said engine operation control means to retard an ignition timing at which an air-fuel mixture is fired in the engine to a point after top-dead-center during said time interval and causing said combustion promoting means to promote combustion of said air-fuel mixture, thereby accelerating said rise in exhaust gas temperature to an effective activation temperature after said engine start.
Claim 2
Dependent Claim
53 words
An exhaust gas purifying system as defined in claim 1, wherein said temperature control means causes said engine operation control means to set said ignition timing so as to produce a rise in in-cylinder pressure after the middle of an expansion stroke during said time interval for said rise in exhaust gas temperature.
Claim 3
Dependent Claim
51 words
An exhaust gas purifying system as defined in any one of the preceding claims 1 and 2, wherein said engine operation control means further alters an in-cylinder air-fuel ratio at which said air-fuel mixture is introduced into said engine in a range from 13.5 to 18.0 during said specific time interval.
Claim 4
Dependent Claim
47 words
An exhaust gas purifying system as defined in any one of the preceding claims 1 and 2, wherein said temperature control means causes said engine operation control means to alter an excessive air ratio of said air-fuel mixture greater than one (1) during said specific time interval.
Claim 5
Dependent Claim
113 words
An exhaust gas purifying system as defined in any one of the preceding claims 1 and 2, wherein said temperature control means causes said engine operation control means to alter an in-cylinder air-fuel ratio at which said air-fuel mixture is introduced into said engine and supply part of intake air directly to said exhaust gas upstream from said catalytic converter so as to alter a virtual exhaust air-fuel ratio, defined as a ratio of a total amount of intake air including intake air introduced into said air-fuel mixture and said intake air supplied to said exhaust gas relative to an amount of fuel introduced into said air-fuel mixture, is at greater than 14.5.
Claim 6
Dependent Claim
53 words
An exhaust gas purifying system as defined in any one of the preceding claims 1 to 5, wherein said temperature control means causes said engine operation control means to alter said ignition timing to said point after top-dead-center after the engine has attained a specified speed of revolution subsequently to said engine start.
Claim 7
Dependent Claim
72 words
An exhaust gas purifying system as defined in any one of the preceding claims 1 to 6, wherein said engine operation control means includes a heater incorporated lambda oxygen (λO 2 ) sensor for monitoring a concentration of oxygen in the exhaust gas, based on which said engine operation control means performs feedback control of said in-cylinder air-fuel ratio toward a stoichiometric air-fuel ratio as a target ratio during said time interval.
Claim 8
Dependent Claim
66 words
An exhaust gas purifying system as defined in any one of the preceding claims 1 to 7, wherein said temperature control means causes said engine operation control means to regulate an amount of intake air introduced into the engine independently from operation of a throttle valve of said engine operation control means so as to maintain a specified speed of the engine in said time interval.
Claim 9
Dependent Claim
57 words
An exhaust gas purifying system as defined in claim 8, wherein said temperature control means causes said engine control means to retard said ignition timing to a point more later but before top-dead-center when the vehicle starts under a driving condition during said time interval than when driving under the same driving condition after said time interval.
Claim 10
Dependent Claim
63 words
An exhaust gas purifying system as defined in claim 9, wherein, when the vehicle starts during said time interval, said temperature control means causes said engine control means to retard said ignition timing to a point more later but before top-dead-center while the vehicle drives with engine output lower than a specified level than while driving with the same level of engine output.
Claim 11
Dependent Claim
40 words
An exhaust gas purifying system as defined in any one of the preceding claims 1 to 10, wherein said combustion promoting means includes turbulence generating means for generating enhanced turbulence of said air-fuel mixture in a cylinder of the engine.
Claim 12
Dependent Claim
36 words
An exhaust gas purifying system as defined in any one of the preceding claims 1 to 10, wherein said combustion promoting means includes an air-mixing type of a fuel injector for delivering fuel mixed with air.
Claim 13
Dependent Claim
30 words
An exhaust gas purifying system as defined in any one of the preceding claims 1 to 10, wherein said combustion promoting means includes ignition means for providing high ignition energy.
Claim 14
Dependent Claim
33 words
An exhaust gas purifying system as defined in any one of the preceding claims 1 to 13, wherein said temperature control means terminates said rise in exhaust gas temperature after said time interval.
Claim 15
Dependent Claim
53 words
An exhaust gas purifying system as defined in any one of the preceding claims 1 to 13, and further comprising temperature monitoring means for detecting a specified temperature of the exhaust gas after said catalytic converter at which said temperature control means terminates said time interval for said rise in exhaust gas temperature.
Claim 16
Dependent Claim
49 words
An exhaust gas purifying system as defined in any one of the preceding claims 1 to 13, and further comprising temperature monitoring means for detecting a specified temperature of engine cooling water at which said temperature control means terminates said time interval for said rise in exhaust gas temperature.
Claim 17
Independent Claim
123 words
A method of purifying exhaust gas discharged from a reciprocating internal combustion engine equipped with a catalytic converter in an exhaust system, said exhaust gas purifying method comprising the steps of: monitoring a thermal condition of the engine after an engine start; and retarding an ignition timing at which an air-fuel mixture is fired in the engine to a point after top-dead-center, while controlling the engine to burn an air-fuel mixture with a high combustion efficiency so as to stabilize engine cycling, for a time interval so as to cause a rise in exhaust gas temperature when the engine is monitored to be still in a cold condition, thereby accelerating a rise in temperature of said catalytic converter to an effective activation temperature.
Claim 18
Dependent Claim
43 words
An exhaust gas purifying method as defined in claim 17, wherein said ignition timing is set so as to produce a rise in in-cylinder pressure after the middle of an expansion stroke during said time interval for said rise in exhaust gas temperature.
Claim 19
Independent Claim
103 words
A method of purifying exhaust gas discharged from a reciprocating internal combustion engine equipped with a catalytic converter in an exhaust system, said exhaust gas purifying method comprising the steps of: monitoring a thermal condition of the engine after an engine start; and retarding an ignition timing at which an air-fuel mixture is fired in the engine to a point after top-dead-center for a time interval so as to cause a rise in exhaust gas temperature when the engine is monitored to be still in a cold condition, thereby accelerating a rise in temperature of said catalytic converter to an effective activation temperature.
References Cited (Backward Citations)
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