Methods and system for controlling surge in a two-stage turbocharger
원문보기
IPC분류정보
국가/구분
United States(US) Patent
등록
국제특허분류(IPC7판)
F02D-041/00
F02D-023/00
F02B-037/013
F02M-026/43
F02M-026/08
F02B-029/04
F02B-037/18
F02B-037/12
F02M-026/28
출원번호
US-0570462
(2012-08-09)
등록번호
US-9822694
(2017-11-21)
발명자
/ 주소
Mischler, James Robert
Loringer, Daniel Edward
Blythe, Neil Xavier
Henry, Luke
Malone, Matthew John
Polkus, Greg Thomas
출원인 / 주소
General Electric Company
대리인 / 주소
Global Patent Operation
인용정보
피인용 횟수 :
1인용 특허 :
4
초록▼
Various methods and systems are provided for controlling air flow in a two-stage turbocharger. In one example, an engine method comprises adjusting one or more exhaust gas recirculation valves to maintain a first turbocharger within a first air flow range, and adjusting a turbocharger bypass valve t
Various methods and systems are provided for controlling air flow in a two-stage turbocharger. In one example, an engine method comprises adjusting one or more exhaust gas recirculation valves to maintain a first turbocharger within a first air flow range, and adjusting a turbocharger bypass valve to maintain a second turbocharger within a second air flow range.
대표청구항▼
1. A method, comprising: adjusting a turbocharger bypass valve to maintain a second turbocharger within a second air flow range;adjusting a first exhaust gas recirculation valve and a second exhaust gas recirculation valve based on a designated intake oxygen amount, both exhaust gas recirculation va
1. A method, comprising: adjusting a turbocharger bypass valve to maintain a second turbocharger within a second air flow range;adjusting a first exhaust gas recirculation valve and a second exhaust gas recirculation valve based on a designated intake oxygen amount, both exhaust gas recirculation valves further selectively adjusted based on the adjustment of the turbocharger bypass valve to decrease exhaust gas recirculation flow to an intake of an engine in order to maintain a first turbocharger within a first air flow range, different than the second air flow range; andcompensating for the decreased exhaust gas recirculation flow by adjusting one or more engine operating parameters. 2. The method of claim 1, wherein compensating for the decreased exhaust gas recirculation flow by adjusting one or more engine operating parameters comprises adjusting engine speed without increasing vehicle speed to maintain the first and second turbochargers within the first air flow range and the second air flow range, respectively, and wherein the first and second turbochargers are arranged in series. 3. The method of claim 1, further comprising adjusting the turbocharger bypass valve to maintain cylinder pressure below a peak combustion pressure. 4. The method of claim 1, wherein the turbocharger bypass valve comprises a turbine bypass valve of the second turbocharger, the turbine bypass valve coupled in a bypass line, the bypass line including an inlet coupled to an exhaust passage upstream of an inlet of a turbine of the second turbocharger and an outlet coupled to the exhaust passage downstream of an outlet of the turbine of the second turbocharger. 5. The method of claim 1, wherein the turbocharger bypass valve comprises a compressor bypass valve of the second turbocharger. 6. The method of claim 4, further comprising directing exhaust gas from the engine to the turbine of the second turbocharger, directing exhaust gas from the turbine of the second turbocharger to a turbine of the first turbocharger, and when the first exhaust gas recirculation valve is open, directing a portion of exhaust gas from upstream of the turbine of the second turbocharger back to the intake of the engine, where the outlet of the bypass line is coupled to the exhaust passage upstream of an inlet of the turbine of the first turbocharger. 7. The method of claim 1, wherein adjusting the first exhaust gas recirculation valve and the second exhaust gas recirculation valve based on a desired intake oxygen amount comprises: adjusting the first and second exhaust gas recirculation valves to respective base exhaust gas recirculation positions that provide the designated intake oxygen amount; andwherein both exhaust gas recirculation valves being further selectively adjusted based on the adjustment of the turbocharger bypass valve comprises, responsive to air flow through the first turbocharger being at or below a surge level, adjusting the first and second exhaust gas recirculation valves away from the respective base exhaust gas recirculation positions to maintain the first turbocharger within the first air flow range. 8. The method of claim 1, wherein the first air flow range comprises a first mass air flow above a surge level and below a choke level for the first turbocharger, and wherein the second air flow range comprises a second mass air flow above a surge level and below a choke level for the second turbocharger. 9. The method of claim 1, wherein the first and second turbochargers have relative to each other at least one difference selected from: air output pressure, rotational speed, air mass throughput, surge threshold value, and stall state threshold value; and, the adjusting of the first and second exhaust gas recirculation valves is based at least in part on the air output pressure, rotational speed, air mass throughput, surge threshold value, or stall state threshold value of the first turbocharger, the second turbocharger, or a combination of both the first and second turbochargers. 10. An engine method, comprising: adjusting an exhaust gas recirculation amount provided to an intake of an engine responsive to an actual exhaust gas recirculation amount deviating from a desired exhaust gas recirculation amount, the desired exhaust gas recirculation amount a function of a designated intake oxygen fraction;adjusting mass air flow through a high-pressure stage of a two-stage turbocharger to maintain the high-pressure stage below a maximum mass air flow; andresponsive to operation at or below a surge level, instead of adjusting the exhaust gas recirculation amount responsive to the actual exhaust gas recirculation amount deviating from the desired exhaust gas recirculation amount, reducing the exhaust gas recirculation amount provided to the intake of the engine to prevent a surge event of a low-pressure stage of the two-stage turbocharger. 11. The method of claim 10, wherein adjusting the mass air flow through the high-pressure stage further comprises adjusting the mass air flow to maintain a designated peak combustion pressure. 12. The method of claim 10, wherein adjusting the mass air flow through the high-pressure stage further comprises adjusting a turbine bypass valve of the high-pressure stage. 13. The method of claim 10, wherein the exhaust gas recirculation amount is reduced to prevent the surge event responsive to a decrease in engine load. 14. The method of claim 13, wherein the high-pressure stage includes a different transient response to the decrease in engine load than a low-pressure stage transient response to the decrease in engine load, and further comprising, during the decrease in engine load, reducing the exhaust gas recirculation amount in order to compensate for the different transient responses. 15. The method of claim 10, wherein the exhaust gas recirculation amount is reduced to prevent the surge event responsive to the adjusting of the mass air flow through the high-pressure stage, the adjusting of the mass air flow through the high-pressure stage including moving a turbine bypass valve of the high-pressure stage into an open position. 16. The method of claim 10, wherein the exhaust gas recirculation amount is decreased based on a trajectory of exhaust gas recirculation amounts that track a surge level of the low-pressure stage, the trajectory including a path through a compressor map of the low-pressure stage defining a series of pressure ratio and mass flow points, the path parallel to the surge level. 17. The method of claim 10, further comprising, responsive to reducing the exhaust gas recirculation amount, retarding fuel injection timing by an amount proportional to the reduction of the exhaust gas recirculation amount. 18. The method of claim 10, further comprising, responsive to reducing the exhaust gas recirculation amount, increasing engine speed to generate excess torque beyond a traction demand and dissipating excess energy from the excess torque to a self-load system. 19. An engine system, comprising: an engine;a two-stage turbocharger system coupled to the engine and including a high-pressure stage and a low-pressure stage, airflow through the high-pressure stage controlled by a turbine bypass valve;an exhaust gas recirculation (EGR) system including an EGR metering valve and an EGR bypass valve, the EGR system configured to selectively route exhaust from a first subset of cylinders of the engine to an intake of the engine via the EGR metering valve or to atmosphere via the EGR bypass valve, the EGR bypass valve positioned upstream of the high-pressure stage; anda control unit storing instructions to: during a first condition, adjust the EGR metering valve and EGR bypass valve to deliver a first amount of EGR to the intake of the engine based on a desired intake oxygen fraction; andduring a second condition and responsive to the first amount of EGR causing the low-pressure stage to operate at or below a surge level, adjust the EGR metering valve and EGR bypass valve to deliver a second amount of EGR to prevent surge of the low-pressure stage of the two-stage turbocharger system. 20. The engine system of claim 19, wherein the first condition comprises steady state operating conditions, and wherein the second condition comprises decreasing engine load, and wherein the EGR system is configured such that all exhaust gas from a second subset of cylinders of the engine is routed to atmosphere. 21. The engine system of claim 19, wherein the first condition comprises a mass air flow through the high-pressure stage of the two-stage turbocharger system being above a threshold, and wherein the second condition comprises the mass air flow through the high-pressure stage of the two-stage turbocharger system being below the threshold. 22. The engine system of claim 21, wherein the control unit includes further instructions to control the mass air flow through the high-pressure stage based on a designated high-pressure turbocharger speed and a designated cylinder pressure. 23. The engine system of claim 22, wherein the turbine bypass valve is coupled in a bypass line including an inlet coupled to an exhaust passage upstream of the high-pressure stage and an outlet coupled to the exhaust passage downstream of the high-pressure stage and upstream of the low-pressure stage, and wherein the control unit includes further instructions to adjust the turbine bypass valve of the high-pressure stage to maintain the mass air flow through the high-pressure stage below a designated maximum amount.
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이 특허에 인용된 특허 (4)
Tomita, Tetsuji; Ibuki, Taku; Hirosawa, Yoshihisa, Apparatus for determining an abnormality of a control valve of an internal combustion engine.
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