EGR system for internal combustion engine and method for controlling the same
원문보기
IPC분류정보
국가/구분
United States(US) Patent
등록
국제특허분류(IPC7판)
F02M-025/07
F02B-047/08
F02B-033/44
출원번호
US-0441241
(2008-01-10)
등록번호
US-8220443
(2012-07-17)
우선권정보
JP-2007-009272 (2007-01-18)
국제출원번호
PCT/IB2008/000042
(2008-01-10)
§371/§102 date
20090313
(20090313)
국제공개번호
WO2008/087513
(2008-07-24)
발명자
/ 주소
Murata, Hiroki
Nagae, Masahiro
Shimizu, Hajime
Nakayama, Shigeki
Onishi, Tomomi
출원인 / 주소
Toyota Jidosha Kabushiki Kaisha
대리인 / 주소
Sughrue Mion, PLLC
인용정보
피인용 횟수 :
9인용 특허 :
7
초록▼
An EGR system includes a high-pressure EGR unit and a low-pressure EGR unit. During the steady operation of an internal combustion engine, the high-pressure EGR gas and the low-pressure EGR gas are mixed with each other at a mixture ratio, in which the ratio of the high-pressure EGR gas amount to th
An EGR system includes a high-pressure EGR unit and a low-pressure EGR unit. During the steady operation of an internal combustion engine, the high-pressure EGR gas and the low-pressure EGR gas are mixed with each other at a mixture ratio, in which the ratio of the high-pressure EGR gas amount to the entire EGR gas amount is higher than that in a known mixture ratio, and then recirculated back to the internal combustion engine. In the engine speed-up transitional operation period, the opening amount of a high-pressure EGR valve is adjusted to the opening amount that is much smaller than the target opening amount corresponding to the target operation mode. Thus, it is possible to suppress occurrence of the situation where the entire EGR gas amount is excessive in the period in which the low-pressure EGR gas amount does not decrease by a sufficient amount.
대표청구항▼
1. An EGR system for an internal combustion engine, comprising: a turbocharger that includes a compressor arranged in an intake passage of the internal combustion engine, and a turbine arranged in an exhaust passage of the internal combustion engine:a high-pressure EGR unit that recirculates a porti
1. An EGR system for an internal combustion engine, comprising: a turbocharger that includes a compressor arranged in an intake passage of the internal combustion engine, and a turbine arranged in an exhaust passage of the internal combustion engine:a high-pressure EGR unit that recirculates a portion of exhaust gas back to the internal combustion engine through a high-pressure EGR passage that provides communication between the exhaust passage, at a portion upstream of the turbine, and the intake passage, at a portion downstream of the compressor;a low-pressure EGR unit that recirculates a portion of exhaust gas back to the internal combustion engine through a low-pressure EGR passage that provides communication between the exhaust passage, at a portion downstream of the turbine, and the intake passage, at a portion upstream of the compressor;a high-pressure EGR valve that is provided in the high-pressure EGR passage, and that changes a flow passage area of the high-pressure EGR passage;a low-pressure EGR valve that is provided in the low-pressure EGR passage, and that changes a flow passage area of the low-pressure EGR passage;an EGR control unit that adjusts an opening amount of the high-pressure EGR valve to a reference high-pressure EGR valve opening amount determined based on an operation mode of the internal combustion engine, and adjusts an opening amount of the low-pressure EGR valve to a reference low-pressure EGR valve opening amount determined based on the operation mode of the internal combustion engine,wherein,in a transitional period in which the operation mode of the internal combustion engine is changing from a predetermined first operation mode to a second operation mode in which a load, which is higher than a load in the first operation mode, is applied to the internal combustion engine, the EGR control unit adjusts the opening amount of the high-pressure EGR valve to an opening amount that is smaller than a reference high-pressure EGR valve opening amount corresponding to the second operation mode; andan engine speed-up prediction unit that predicts whether the operation mode of the internal combustion engine is changed from the first operation mode to the second operation mode,wherein,when the engine speed-up prediction unit predicts that the operation mode of the internal combustion engine is changed from the first operation mode to the second operation mode, the EGR control unit adjusts the opening amount of the high-pressure EGR valve to an opening amount that is larger than a reference high-pressure EGR valve opening amount corresponding to the first operation mode so that a ratio of an amount of exhaust gas, recirculated back to the internal combustion engine by the high-pressure EGR unit, to a total amount of exhaust gas, recirculated back to the internal combustion engine by the high-pressure EGR unit and the low-pressure EGR unit, is higher than that before the engine speed-up prediction unit predicts that the operation mode of the internal combustion engine is changed from the first operation mode to the second operation mode. 2. An EGR system for an internal combustion engine comprising: a turbocharger that includes a compressor arranged in an intake passage of the internal combustion engine, and a turbine arranged in an exhaust passage of the internal combustion engine:a high-pressure EGR unit that recirculates a portion of exhaust gas back to the internal combustion engine through a high-pressure EGR passage that provides communication between the exhaust passage, at a portion upstream of the turbine, and the intake passage, at a portion downstream of the compressor;a low-pressure EGR unit that recirculates a portion of exhaust gas back to the internal combustion engine through a low-pressure EGR passage that provides communication between the exhaust passage, at a portion downstream of the turbine, and the intake passage, at a portion upstream of the compressor;a high-pressure EGR valve that is provided in the high-pressure EGR passage, and that changes a flow passage area of the high-pressure EGR passage;a low-pressure EGR valve that is provided in the low-pressure EGR passage, and that changes a flow passage area of the low-pressure EGR passage; andan EGR control unit that adjusts an opening amount of the high-pressure EGR valve to a reference high-pressure EGR valve opening amount determined based on an operation mode of the internal combustion engine, and adjusts an opening amount of the low-pressure EGR valve to a reference low-pressure EGR valve opening amount determined based on the operation mode of the internal combustion engine,wherein,in a transitional period in which the operation mode of the internal combustion engine is changing from a predetermined first operation mode to a second operation mode in which a load, which is higher than a load in the first operation mode, is applied to the internal combustion engine, the EGR control unit adjusts the opening amount of the high-pressure EGR valve to an opening amount that is smaller than a reference high-pressure EGR valve opening amount corresponding to the second operation mode,whereinthe EGR control unit maintains the opening amount of the high-pressure EGR valve at the opening amount that is smaller than the reference high-pressure EGR valve opening amount corresponding to the second operation mode during a predetermined period after the operation mode of the internal combustion engine is changed to the second operation mode. 3. An EGR system for an internal combustion engine comprising: a turbocharger that includes a compressor arranged in an intake passage of the internal combustion engine, and a turbine arranged in an exhaust passage of the internal combustion engine;a high-pressure EGR unit that recirculates a portion of exhaust gas back to the internal combustion engine through a high pressure EGR passage that provides communication between the exhaust passage, at a portion upstream of the turbine, and the intake passage, at a portion downstream of the compressor;a low-pressure EGR unit that recirculates a portion of exhaust gas back to the internal combustion engine through a low-pressure EGR passage that provides communication between the exhaust passage, at a portion downstream of the turbine, and the intake passage, at a portion upstream of the compressor;a high-pressure EGR valve that is provided in the high-pressure EGR passage, and that changes a flow passage area of the high-pressure EGR passage;a low-pressure EGR valve that is provided in the low-pressure EGR passage, and that changes a flow passage area of the low-pressure EGR passage; andan EGR control unit that adjusts an opening amount of the high-pressure EGR valve to a reference high-pressure EGR valve opening amount determined based on an operation mode of the internal combustion engine, and adjusts an opening amount of the low-pressure EGR valve to a reference low-pressure EGR valve opening amount determined based on the operation mode of the internal combustion engine,wherein,in a transitional period in which the operation mode of the internal combustion engine is changing from a predetermined first operation mode to a second operation mode in which a load, which is higher than a load in the first operation mode, is applied to the internal combustion engine, the EGR control unit adjusts the opening amount of the high-pressure EGR valve to an opening amount that is smaller than a reference high-pressure EGR valve opening amount corresponding to the second operation mode,wherein, after the operation mode of the internal combustion engine is changed to the second operation mode, the EGR control unit gradually increases the opening amount of the high-pressure EGR valve from the opening amount, which is smaller than the reference high-pressure EGR valve opening amount corresponding to the second operation mode, toward the reference high-pressure EGR valve opening amount corresponding to the second operation mode, as an amount of exhaust gas recirculated back to the internal combustion engine by the low-pressure EGR unit is gradually decreased toward a reference low-pressure EGR gas amount corresponding to the second operation mode. 4. A method for controlling an EGR system for an internal combustion engine, the EGR system including: a turbocharger that includes a compressor arranged in an intake passage of the internal combustion engine, and a turbine arranged in an exhaust passage of the internal combustion engine;a high-pressure EGR unit that recirculates a portion of exhaust gas back to the internal combustion engine through a high-pressure EGR passage that provides communication between the exhaust passage, at a portion upstream of the turbine, and the intake passage, at a portion downstream of the compressor;a low-pressure EGR unit that recirculates a portion of exhaust gas back to the internal combustion engine through a low-pressure EGR passage that provides communication between the exhaust passage, at a portion downstream of the turbine, and the intake passage, at a portion upstream of the compressor;a high-pressure EGR valve that is provided in the high-pressure EGR passage, and that changes a flow passage area of the high-pressure EGR passage, anda low-pressure EGR valve that is provided in the low-pressure EGR passage, and that changes a flow passage area of the low-pressure EGR passage,the method comprising:adjusting an opening amount of the high-pressure EGR valve to a reference high-pressure EGR valve opening amount determined based on an operation mode of the internal combustion engine, and adjusting an opening amount of the low-pressure EGR valve to a reference low-pressure EGR valve opening amount determined based on the operation mode of the internal combustion engine;adjusting, in a transitional period in which the operation mode of the internal combustion engine is changing from a predetermined first operation mode to a second operation mode in which a load higher than a load in the first operation mode is applied to the internal combustion engine, the opening amount of the high-pressure EGR valve to an opening amount that is smaller than a reference high-pressure EGR valve opening amount corresponding to the second operation mode;predicting whether the operation mode of the internal combustion engine is changed from the first operation mode to the second operation mode; andadjusting the opening amount of the high-pressure EGR valve to an opening amount that is larger than a reference high-pressure EGR valve opening amount corresponding to the first operation mode when it is predicted that the operation mode of the internal combustion engine is changed from the first operation mode to the second operation mode, so that a ratio of an amount of exhaust gas recirculated back to the internal combustion engine by the high-pressure EGR unit to a total amount of exhaust gas recirculated back to the internal combustion engine by the high-pressure EGR unit and the low-pressure EGR unit is higher than that before it is predicted that the operation mode of the internal combustion engine is changed from the first operation mode to the second operation. 5. A method for controlling an EGR system for an internal combustion engine, the EGR system including: a turbocharger that includes a compressor arranged in an intake passage of the internal combustion engine, and a turbine arranged in an exhaust passage of the internal combustion engine;a high-pressure EGR unit that recirculates a portion of exhaust gas back to the internal combustion engine through a high-pressure EGR passage that provides communication between the exhaust passage, at a portion upstream of the turbine, and the intake passage, at a portion downstream of the compressor;a low-pressure EGR unit that recirculates a portion of exhaust gas back to the internal combustion engine through a low-pressure EGR passage that provides communication between the exhaust passage, at a portion downstream of the turbine, and the intake passage, at a portion upstream of the compressor;a high-pressure EGR valve that is provided in the high-pressure EGR passage, and that changes a flow passage area of the high-pressure EGR passage; anda low-pressure EGR valve that is provided in the low-pressure EGR passage, and that changes a flow passage area of the low-pressure EGR passage,the method comprising:adjusting an opening amount of the high-pressure EGR valve to a reference high-pressure EGR valve opening amount determined based on an operation mode of the internal combustion engine, and adjusting an opening amount of the low-pressure EGR valve to a reference low-pressure EGR valve opening amount determined based on the operation mode of the internal combustion engine; andadjusting in a transitional period in which the operation mode of the internal combustion engine is changing from a predetermined first operation mode to a second operation mode in which a load higher than a load in the first operation mode is applied to the internal combustion engine, the opening amount of the high-pressure EGR valve to an opening amount that is smaller than a reference high-pressure EGR valve opening amount corresponding to the second operation mode,whereinthe opening amount of the high-pressure EGR valve is maintained at the opening amount that is smaller than the reference high-pressure EGR valve opening amount corresponding to the second operation mode during a predetermined period after the operation mode of the internal combustion engine is changed to the second operation mode. 6. A method for controlling an EGR system for an internal combustion engine, the EGR system including: a turbocharger that includes a compressor arranged in an intake passage of the internal combustion engine, and a turbine arranged in an exhaust passage of the internal combustion engine;a high-pressure EGR unit that recirculates a portion of exhaust gas back to the internal combustion engine through a high-pressure EGR passage that provides communication between the exhaust passage, at a portion upstream of the turbine, and the intake passage, at a portion downstream of the compressor;a low-pressure EGR unit that recirculates a portion of exhaust gas back to the internal combustion engine through a low-pressure EGR passage that provides communication between the exhaust passage, at a portion downstream of the turbine, and the intake passage, at a portion upstream of the compressor;a high-pressure EGR valve that is provided in the high-pressure EGR passage, and that changes a flow passage area of the high-pressure EGR passage, anda low-pressure EGR valve that is provided in the low-pressure EGR passage, and that changes a flow passage area of the low-pressure EGR passage,the method comprising:adjusting an opening amount of the high-pressure EGR valve to a reference high-pressure EGR valve opening amount determined based on an operation mode of the internal combustion engine, and adjusting an opening amount of the low-pressure EGR valve to a reference low-pressure EGR valve opening amount determined based on the operation mode of the internal combustion engine; andadjusting, in a transitional period in which the operation mode of the internal combustion engine is changing from a predetermined first operation mode to a second operation mode in which a load higher than a load in the first operation mode is applied to the internal combustion engine, the opening amount of the high-pressure EGR valve to an opening amount that is smaller than a reference high-pressure EGR valve opening amount corresponding to the second operation mode,wherein,after the operation mode of the internal combustion engine is changed to the second operation mode, the opening amount of the high-pressure EGR valve is gradually increased from the opening amount, which is smaller than the reference high-pressure EGR valve opening amount corresponding to the second operation mode, toward the reference high-pressure EGR valve opening amount corresponding to the second operation mode, as an amount of exhaust gas recirculated back to the internal combustion engine by the low-pressure EGR unit is gradually decreased toward a reference low-pressure EGR gas amount corresponding to the second operation mode.
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이 특허에 인용된 특허 (7)
Haugen, David James, Control methods for low emission internal combustion system.
Mayer Andreas (Niederrohrdorf CHX) El-Nashar Ibrahim (Kloten CHX) Spinnler Fritz (Liestal CHX), Method and device for controlling the recirculation of exhaust gas in a pressure wave supercharger for an internal combu.
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