EP0984153A2
Expired / Lapsed
EP
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Control system for turbocharged engine
Assignee: Mazda Motor Corp
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Filing: 1999-08-31
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Granted: —
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Expires: 2019-08-31
Abstract
Abstract A turbocharged engine control system having exhaust gas recirculation control means (26) which detects a value relating to an actual excess air ratio and feedback controls an exhaust gas recirculation valve (5) so as to bring the actual excess air ratio into coincidence with a target excess air ratio and turbine efficiency control means (28) which controls a turbocharger (8) to change turbine efficiency of the turbocharger is comprised of detection means (12) for detecting a value relating to a pressure difference between pressure before and after the exhaust gas recirculation valve (5) and control means (26) for controlling the turbine efficiency control means (28) to vary a change rate at which the turbine efficiency changes so as to become lower as the pressure difference rises. With the turbocharged engine control system, the control is properly performed to improve fuel economy and reduce particulate such as smoke and unburnt fuel and NOx emissions in exhaust gases without causing overshooting and/or hunting.
Inventors
- 👤 Tomoaki Saito
- 👤 Katsuaki Yasutomi
- 👤 Hideki Hosoya
- 👤 Keiji Araki
Bibliographic Details
Application Number
—
Jurisdiction
EP
Data Source
google_patents
Last Synchronized
2026-10-29 15:42
CPC Classifications
F; F02; F02D; F02D41/00; F02D41/0025; F02D41/0047; F02D41/005; F02D41/0052; F02D35/00; F02D35/0015; F02D35/0023; F02D35/0038; F02D41/0002; F02D41/0007; F02D41/02; F02D41/14; F02D41/1438; F02D41/1444; F02D41/1448; F02M; F02M26/00; F02M26/45; F02M26/46; F02M26/47; F02B; F02B29/00; F02B29/04; F02B29/0406; F02M26/02; F02M26/04; F02M26/05; F02M26/09; F02M26/10; F02M26/52; F02M26/55; F02M26/56; F02M26/57; Y; Y02; Y02T; Y02T10/00; Y02T10/10; Y02T10/12; Y02T10/40
Claims Analysis
Total Claims: 9
Claim 1
Independent Claim
130 words
A control system for a turbocharged engine (1) equipped with exhaust gas
recirculation control means (26) for detecting a value relating to an actual excess air ratio and
feedback controlling an exhaust gas recirculation valve (5) so as to bring said actual excess air
ratio into coincidence with a target excess air ratio and turbine efficiency control means (28) for
controlling a turbocharger (8) to change turbine efficiency of said turbocharger, characterized
by: detection means (12) for detecting a value relating to a pressure difference between
pressure before and after said exhaust gas recirculation valve (5), and control means (26, 37)
for controlling said turbine efficiency control means (28) to vary a change rate at which said
turbine efficiency changes so as to become lower as said pressure difference rises.
Claim 2
Dependent Claim
66 words
A control system for a turbocharged engine as defined in claim 1, wherein said
turbine efficiency control means (28) changes said turbine efficiency by changing a nozzle angle
of a turbine nozzle upon which an exhaust gas flow area of a turbine (13) of said turbocharger
(8) depends such that a change rate at which said nozzle angle changes becomes lower as said
pressure difference rises.
Claim 3
Dependent Claim
76 words
A control system for a turbocharged engine as defined in claim 1 or 2, wherein said
turbine efficiency control means (28) includes a waste-gate which is disposed in a passage
through which an exhaust gas flows bypassing a turbine (13) of said turbocharger (8) and
controls operation of said waste-gate to change said turbine efficiency of said turbine (13) such
that a change rate at which said waste-gate operates becomes lower as said pressure difference
rises.
Claim 4
Dependent Claim
91 words
A control system for a turbocharged engine as defined in anyone of the claims 1 to 3, wherein
said detection means (12) comprises a pressure sensor (12) operative to detect intake air pressure of
intake air introduced into an intake passage (2) as said value relating to said pressure difference
between pressure before and after said exhaust gas recirculation valve (5) and said turbine
efficiency control means (28) controls said turbocharger (8) to change said turbine efficiency at
a change rate which is made lower as said intake air pressure rises.
Claim 5
Dependent Claim
53 words
A control system for a turbocharged engine as defined in anyone of the claims 1 to 4, wherein
said turbine efficiency control means (28) controls said turbocharger (8) to change said turbine
efficiency at a change rate which is made small while said turbocharged engine (1) operates at
high speeds and high loads.
Claim 6
Dependent Claim
155 words
A control system for a turbocharged engine as defined in anyone of the claims 1 to 5, wherein said
turbine efficiency control means (28) controls said turbocharger (8) to change a nozzle angle of
a turbine nozzle upon which an exhaust gas flow area of a turbine (13) of said turbocharger (8)
depends so as thereby to change turbine efficiency of said turbocharger, said detection means
(12) detects intake air pressure of intake air introduced into an intake passage (2) as a value
relating to a pressure difference between pressure before and after said exhaust gas recirculation
valve (5), and said control means (26) controls a change rate at which said exhaust gas
recirculation valve (5) is operated to become lower and a change rate of said actual excess air
ratio to become greater when caused by operation of said exhaust gas recirculation valve (5) than
when caused by a change in said nozzle angle.
Claim 7
Dependent Claim
60 words
A control system for a turbocharged engine as defined in anyone of the claims 1 to 6, wherein said
turbine efficiency control means (28) varies a change rate at which said turbine efficiency
changes to be high at the beginning period of acceleration from a state wherein said turbocharged
engine operates in a range of lower speeds and lower loads.
Claim 8
Dependent Claim
42 words
A control system for a turbocharged engine as defined in claim 7, wherein said
turbine efficiency control means (28) varies said change rate to be high during an early stage of
acceleration since an accelerator pedal is in its fully released position.
Claim 9
Dependent Claim
76 words
A control system for a turbocharged engine as defined in anyone of the claims 1 to 8, wherein an
exhaust gas recirculation passage (4) extends from an exhaust passage (3) upstream from a
turbine (13) of said turbocharger (8) and said exhaust gas recirculation control means (26)
feedback controls a valve lift of said exhaust gas recirculation valve (5) so as to bring said actual
excess air ratio into coincidence with said target excess air ratio.
References Cited (Backward Citations)
No citation records indexed.
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