Method to optimize engine operation using active fuel management
원문보기
IPC분류정보
국가/구분
United States(US) Patent
등록
국제특허분류(IPC7판)
F02D-017/02
F02D-041/14
F02D-041/26
F02D-041/00
출원번호
US-0245652
(2016-08-24)
등록번호
US-9903283
(2018-02-27)
발명자
/ 주소
Rayl, Jr., Allen B.
Dibble, Donovan L.
Burleigh, Darrell W.
Haase, Steven J.
출원인 / 주소
GM GLOBAL TECHNOLOGY OPERATIONS LLC
인용정보
피인용 횟수 :
0인용 특허 :
1
초록▼
A method for operating an internal combustion engine includes providing a vehicle having an internal combustion gasoline engine including multiple cylinders and wherein the engine is capable of running on at least one of a plurality firing fractions, providing a vacuum offset (Offsetvac) to adjust a
A method for operating an internal combustion engine includes providing a vehicle having an internal combustion gasoline engine including multiple cylinders and wherein the engine is capable of running on at least one of a plurality firing fractions, providing a vacuum offset (Offsetvac) to adjust airflow capacity for each of the plurality of firing fractions, determining a torque capacity of each of the plurality firing fractions and a plurality of available firing fractions that provides at least enough torque capacity to accommodate a current torque requested (Treq), determining a plurality of viable firing fractions of the plurality of available firing fractions, and determining and implementing an optimal firing fraction of the viable firing fractions if the optimal firing fraction provides enough fuel economy benefit over a current firing fraction.
대표청구항▼
1. A method for operating an internal combustion engine, the method comprising: providing a vehicle having an internal combustion gasoline engine including multiple cylinders and wherein the engine is capable of running on at least one of a plurality of firing fractions;providing a vacuum offset (Of
1. A method for operating an internal combustion engine, the method comprising: providing a vehicle having an internal combustion gasoline engine including multiple cylinders and wherein the engine is capable of running on at least one of a plurality of firing fractions;providing a vacuum offset (Offsetvac) to adjust airflow capacity for each of the plurality of firing fractions;determining a torque capacity of each of the plurality of firing fractions and a plurality of available firing fractions that provides at least enough torque capacity to accommodate a current torque requested (Treq), and wherein determining the torque capacity of each of the plurality of firing fractions comprises: determining a net torque capacity (Tnet) of the engine;determining a maximum brake torque (TFF) for each firing fraction; anddetermining a minimum firing fraction that produces at least enough brake torque TFF to accommodate the current torque request Treq;determining a plurality of viable firing fractions of the plurality of available firing fractions; anddetermining and implementing an optimal firing fraction of the viable firing fractions if the optimal firing fraction provides enough fuel economy benefit over a current firing fraction. 2. The method of operating an internal combustion engine of claim 1 wherein providing the vacuum offset (Offsetvac)) to adjust airflow capacity for each of the firing fractions further comprises: increasing Offsetvac if an intake manifold vacuum (Vac) is less than a first predetermined threshold for a period of time (T);decreasing Offsetvac if an intake manifold vacuum (Vac) is greater than a first predetermined threshold for a period of time (T) and an engine load is high; andmaintaining a current Offsetvac. 3. The method of operating an internal combustion engine of claim 1 wherein determining the net torque capacity (Tnet) of the engine further comprises determining the Tnet as a function of engine speed (RPM), maximum torque cam position, barometric pressure, Vac, Offsetvac, temperature, and humidity. 4. The method of operating an internal combustion engine of claim 1 wherein determining the maximum brake torque (TFF) for each firing fraction further comprises determining TFF by the equation: TFF=Tnet*FF+Tfriction wherein Tfriction is a constant torque loss due to friction losses of the engine. 5. The method of operating an internal combustion engine of claim 1 wherein determining a plurality of viable firing fractions of the plurality of available firing fractions further comprises: determining a new engine speed EngSpdnew and a transit engine speed EngSpdtransit for one of the plurality of available firing fractions;determining a minimum engine speed EngSpdmin of the one of the plurality of available firing fractions;determining a maximum engine speed EngSpdmax of the one of the plurality of available firing fractions, and wherein EngSpdmax is the highest of a current engine speed EngSpdcurrent, EngSpdnew, and EngSpdtransit;determining a net torque TnetESmin and TnetESmax for each of EngSpdmin and EngSpdmax;determining a torque limit Tlimit as the minimum of TnetESmin and TnetESmax;assigning the one of the plurality of available firing fractions as a viable firing fraction if a brake torque limit of a firing fraction Tbrklim is greater than the requested brake torque Tbrkreq in addition to a hysteresis and if Tlimit is greater than a requested net torque Tnetreq in addition to the hysteresis; andassigning the one of the plurality of available firing fractions as a nonviable firing fraction if the brake torque limit of the firing fraction Tbrklim is not greater than the requested brake torque Tbrkreq in addition to the hysteresis or if Tlimit is not greater than a requested net torque Tnetreq in addition to the hysteresis. 6. The method of operating an internal combustion engine of claim 1 wherein determining and implementing an optimal firing fraction of the viable firing fractions if the optimal firing fraction provides enough fuel economy benefit over a current firing fraction further comprises: determining a most fuel efficient of the plurality of viable firing fractions FFbest;determining a fuel efficiency of the current firing fraction FFcurrent;determines a ratio of a fuel efficiency Effratio of the most fuel efficient firing fraction FFbest to the efficiency of the current firing fraction FFcurrent;maintaining the FFcurrent if the Effratio is greater than a first threshold ratio TH1;switching to the FFbest if the Effratio is less than a second threshold ratio TH2;maintaining the FFcurrent and determining the most fuel efficient of the plurality of viable firing fractions FFbest if the Effratio is less than a first threshold ratio TH1 and greater than a second threshold ratio TH2. 7. The method of operating an internal combustion engine of claim 6 wherein maintaining the FFcurrent if the Effratio is greater than a first threshold ratio TH1 further comprises maintaining the FFcurrent if the Effratio is greater than 98.5% and switching to the FFbest if the Effratio is less than a second threshold ratio TH2 further comprises switching to the FFbest if the Effratio is less than 95%. 8. A method for operating an internal combustion engine, the method comprising: providing a vehicle having an internal combustion gasoline engine including multiple cylinders and wherein the engine is capable of running on at least one of a plurality firing fractions;providing a vacuum offset (Offsetvac) to adjust airflow capacity for each of the plurality of firing fractions providing a vacuum offset (Offsetvac) to adjust airflow capacity for each of the firing fractions by: increasing Offsetvac if an intake manifold vacuum (Vac) is less than a first predetermined threshold for a period of time (T);decreasing Offsetvac if an intake manifold vacuum (Vac) is greater than a first predetermined threshold for a period of time (T) and an engine load is high; andmaintaining a current Offsetvac.;determining a torque capacity of each of the plurality firing fractions and a plurality of available firing fractions that provides at least enough torque capacity to accommodate a current torque requested (Treq) by: determining the net torque capacity (Tnet) of the engine;determining the maximum brake torque (TFF) for each firing fraction; anddetermining a minimum firing fraction that produces at least enough brake torque TFF to accommodate a current torque request Treq;determining a plurality of viable firing fractions of the plurality of available firing fractions; anddetermining and implementing an optimal firing fraction of the viable firing fractions if the optimal firing fraction provides enough fuel economy benefit over a current firing fraction. 9. The method of operating an internal combustion engine of claim 8 wherein determining the net torque capacity (Tnet) of the engine further comprises determining the Tnet as a function of engine speed (RPM), maximum torque cam position, barometric pressure, Vac, Offsetvac, temperature, and humidity. 10. The method of operating an internal combustion engine of claim 8 wherein determining the maximum brake torque (TFF) for each firing fraction further comprises determining TFF by the equation: TFF=Tnet*FF+Tfriction wherein Tfriction is a constant torque loss due to friction losses of the engine. 11. The method of operating an internal combustion engine of claim 8 wherein determining a plurality of viable firing fractions of the plurality of available firing fractions further comprises: determining a new engine speed EngSpdnew and a transit engine speed EngSpdtransit for one of the plurality of available firing fractions;determining a minimum engine speed EngSpdmin of the one of the plurality of available firing fractions;determining finds the maximum engine speed EngSpdmax of the one of the plurality of available firing fractions, and wherein EngSpdmax is the highest of a current engine speed EngSpdcurrent, EngSpdnew, and EngSpdtransit;determining a net torque TnetESmin and TnetESmax for each of EngSpdmin and EngSpdmax;determining a torque limit Tlimit as the minimum of TnetESmin and TnetESmax;assigning the one of the plurality of available firing fractions as a viable firing fraction if the brake torque limit of the firing fraction Tbrklim is greater than the requested brake torque Tbrkreq in addition to the hysteresis and if Tlimit is greater than a requested net torque Tnetreq in addition to a hysteresis; andassigning the one of the plurality of available firing fractions as a nonviable firing fraction if the brake torque limit of the firing fraction Tbrklim is not greater than the requested brake torque Tbrkreq in addition to the hysteresis or if Tlimit is not greater than a requested net torque Tnetreq in addition to the hysteresis. 12. The method of operating an internal combustion engine of claim 8 wherein determining and implementing an optimal firing fraction of the viable firing fractions if the optimal firing fraction provides enough fuel economy benefit over a current firing fraction further comprises: determining the most fuel efficient of the plurality of viable firing fractions FFbest;determining the fuel efficiency of the current firing fraction FFcurrent;determines a ratio of the fuel efficiency Effratio of the most fuel efficient firing fraction FFbest to the efficiency of the current firing fraction FFcurrent;maintaining the FFcurrent if the Effratio is greater than a first threshold ratio TH1;switching to the FFbest if the Effratio is less than a second threshold ratio TH2;maintaining the FFcurrent and determining the most fuel efficient of the plurality of viable firing fractions FFbest if the Effratio is less than a first threshold ratio TH1 and greater than a second threshold ratio TH2. 13. The method of operating an internal combustion engine of claim 8 wherein maintaining the FFcurrent if the Effratio is greater than a first threshold ratio TH1 further comprises maintaining the FFcurrent if the Effratio is greater than 98.5% and switching to the FFbest if the Effratio is less than a second threshold ratio TH2 further comprises switching to the FFbest if the Effratio is less than 95%. 14. A method for operating an internal combustion engine, the method comprising: providing a vehicle having an internal combustion gasoline engine including multiple cylinders and wherein the engine is capable of running on at least one of a plurality firing fractions;providing a vacuum offset (Offsetvac) to adjust airflow capacity for each of the plurality of firing fractions providing a vacuum offset (Offsetvac) to adjust airflow capacity for each of the firing fractions by: increasing Offsetvac if an intake manifold vacuum (Vac) is less than a first predetermined threshold for a period of time (T);decreasing Offsetvac if an intake manifold vacuum (Vac) is greater than a first predetermined threshold for a period of time (T) and an engine load is high; and maintaining a current Offsetvac.;determining a torque capacity of each of the plurality firing fractions and a plurality of available firing fractions that provides at least enough torque capacity to accommodate a current torque requested (Treq) by: determining the net torque capacity (Tnet) of the engine;determining the maximum brake torque (TFF) for each firing fraction by the equation: TFF=Tnet*FF+Tfriction wherein Tfriction is a constant torque loss due to friction losses of the engine; anddetermining a minimum firing fraction that produces at least enough brake torque TFF to accommodate a current torque request Treq;determining a plurality of viable firing fractions of the plurality of available firing fractions; anddetermining and implementing an optimal firing fraction of the viable firing fractions if the optimal firing fraction provides enough fuel economy benefit over a current firing fraction. 15. The method of operating an internal combustion engine of claim 14 wherein determining the net torque capacity (Tnet) of the engine further comprises determining the Tnet as a function of engine speed (RPM), maximum torque cam position, barometric pressure, Vac, Offsetvac, temperature, and humidity. 16. The method of operating an internal combustion engine of claim 14 wherein determining a plurality of viable firing fractions of the plurality of available firing fractions further comprises: determining a new engine speed EngSpdnew and a transit engine speed EngSpdtransit for one of the plurality of available firing fractions;determining a minimum engine speed EngSpdmin of the one of the plurality of available firing fractions;determining finds the maximum engine speed EngSpdmax of the one of the plurality of available firing fractions, and wherein EngSpdmax is the highest of a current engine speed EngSpdcurrent, EngSpdnew, and EngSpdtransit;determining a net torque TnetESmin and TnetESmax for each of EngSpdmin and EngSpdmax;determining a torque limit Tlimit as the minimum of TnetESmin and TnetESmax;assigning the one of the plurality of available firing fractions as a viable firing fraction if the brake torque limit of the firing fraction Tbrklim is greater than the requested brake torque Tbrkreq in addition to the hysteresis and if Tlimit is greater than a requested net torque Tnetreq in addition to a hysteresis; andassigning the one of the plurality of available firing fractions as a nonviable firing fraction if the brake torque limit of the firing fraction Tbrklim is not greater than the requested brake torque Tbrkreq in addition to the hysteresis or if Tlimit is not greater than a requested net torque Tnetreq in addition to the hysteresis. 17. The method of operating an internal combustion engine of claim 14 wherein determining and implementing an optimal firing fraction of the viable firing fractions if the optimal firing fraction provides enough fuel economy benefit over a current firing fraction further comprises: determining the most fuel efficient of the plurality of viable firing fractions FFbest;determining the fuel efficiency of the current firing fraction FFcurrent;determines a ratio of the fuel efficiency Effratio of the most fuel efficient firing fraction FFbest to the efficiency of the current firing fraction FFcurrent;maintaining the FFcurrent if the Effratio is greater than a first threshold ratio TH1;switching to the FFbest if the Effratio is less than a second threshold ratio TH2;maintaining the FFcurrent and determining the most fuel efficient of the plurality of viable firing fractions FFbest if the Effratio is less than a first threshold ratio TH1 and greater than a second threshold ratio TH2. 18. The method of operating an internal combustion engine of claim 17 wherein maintaining the FFcurrent if the Effratio is greater than a first threshold ratio TH1 further comprises maintaining the FFcurrent if the Effratio is greater than 98.5% and switching to the FFbest if the Effratio is less than a second threshold ratio TH2 further comprises switching to the FFbest if the Effratio is less than 95%.
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이 특허에 인용된 특허 (1)
Li, Jinbiao; Liu, Haifeng, Cylinder firing fraction determination and control systems and methods.
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