System and method for diagnosing a postive crankcase ventilation valve
원문보기
IPC분류정보
국가/구분
United States(US) Patent
등록
국제특허분류(IPC7판)
F02D-041/22
B60W-020/50
B60N-002/00
F01M-013/00
F02D-041/00
출원번호
US-0373154
(2016-12-08)
등록번호
US-10012166
(2018-07-03)
발명자
/ 주소
Dudar, Aed M.
출원인 / 주소
Ford Global Technologies, LLC
대리인 / 주소
Voutyras, Julia
인용정보
피인용 횟수 :
0인용 특허 :
9
초록▼
Methods and systems are provided for diagnosing a positive crankcase valve during a vehicle key-off event. In one example, a method may include controlling a fluid flow from a crankcase of an engine to an intake manifold of the engine via a positive crankcase ventilation valve, and indicating whethe
Methods and systems are provided for diagnosing a positive crankcase valve during a vehicle key-off event. In one example, a method may include controlling a fluid flow from a crankcase of an engine to an intake manifold of the engine via a positive crankcase ventilation valve, and indicating whether the positive crankcase valve is stuck open responsive to spinning the engine unfueled in a reverse direction, and indicating whether the positive crankcase valve is stuck closed responsive to spinning the engine fueled but without spark in a forward direction. In this way, functionality of a positive crankcase ventilation valve may be diagnosed effectively during key-off conditions, which may prevent or reduce engine complications arising from a stuck open or stuck closed positive crankcase valve.
대표청구항▼
1. A method comprising: controlling a fluid flow from a crankcase of an engine to an intake manifold of the engine via a positive crankcase ventilation valve; andin a first condition, indicating whether the positive crankcase valve is stuck open responsive to spinning the engine unfueled in a revers
1. A method comprising: controlling a fluid flow from a crankcase of an engine to an intake manifold of the engine via a positive crankcase ventilation valve; andin a first condition, indicating whether the positive crankcase valve is stuck open responsive to spinning the engine unfueled in a reverse direction; andin a second condition, indicating whether the positive crankcase valve is stuck closed responsive to spinning the engine fueled in a forward direction. 2. The method of claim 1, further comprising: indicating pressure in a crankcase ventilation tube via a pressure sensor, the crankcase ventilation tube fluidically coupling the crankcase to an air intake system configured to draw intake air into the engine; andin the first condition, indicating the positive crankcase valve is stuck open responsive to an increase in pressure in the crankcase ventilation tube above a predetermined pressure change threshold as indicated via the pressure sensor. 3. The method of claim 1, further comprising: sleeping a vehicle controller responsive to a key-off event; andwherein both the first condition and the second condition are carried out responsive to the controller being woken up after a predetermined time period after the key-off event. 4. The method of claim 1, further comprising: controlling an intake air flow to the engine via a throttle positioned in the intake manifold; andin the first condition, controlling the throttle to a position more open than a closed position, and in the second condition, controlling the throttle to a fully open position. 5. The method of claim 1, further comprising: indicating a vehicle occupancy state via seat load cells; andwherein both the first condition and the second condition are conducted responsive to an indication of an absence of vehicle occupancy. 6. The method of claim 1, further comprising: indicating an air/fuel ratio in the intake manifold of the engine via an intake air oxygen sensor; andin the second condition, indicating the positive crankcase valve is stuck closed responsive to the indicated air/fuel ratio less than a predetermined air/fuel ratio threshold. 7. The method of claim 6, wherein the first condition further comprises indicating air/fuel ratio in the intake manifold via the intake air oxygen sensor during spinning the engine unfueled in reverse; and wherein the second condition is commenced responsive to an indication of a lean air/fuel ratio in the intake manifold as indicated by the intake air oxygen sensor. 8. The method of claim 1, further comprising: controlling fuel injection to one or more cylinders of the engine via one or more fuel injectors;providing spark to one or more of the engine cylinders via one or more spark plugs;wherein the first condition includes spinning the engine unfueled in reverse without fuel injection and without spark to any of the engine cylinders; andwherein the second condition includes spinning the engine fueled in the forward direction by providing fuel injection to one or more cylinders, but not providing spark to the one or more cylinders receiving fuel injection so that fuel injected to the one or more engine cylinders is not combusted. 9. The method of claim 8, wherein fuel injected into the one or more engine cylinders that is not combusted is drawn into the crankcase. 10. A system for a hybrid vehicle, comprising: an engine including an engine intake manifold, an engine exhaust manifold, a crankcase, and a compressor supplying compressed air to the intake manifold;an electric motor coupled to the engine;a crankcase ventilation tube connecting the crankcase to a fresh air intake passage upstream of the compressor;a pressure sensor configured to indicate pressure in the crankcase ventilation tube;a positive crankcase ventilation line connecting the crankcase to the intake manifold;a positive crankcase valve positioned in the positive crankcase ventilation line;an intake air oxygen sensor positioned in the intake manifold; anda controller storing instructions in non-transitory memory that, when executed, cause the controller to:responsive to a predetermined time duration elapsing since a key-off event, spin the engine in a reverse direction via the electric motor and indicate whether the positive crankcase valve is stuck open based on a pressure level indicated via the pressure sensor configured to indicate pressure in the crankcase ventilation tube; andresponsive to an indication that the positive crankcase valve is not stuck open:spin the engine in the forward direction via the electric motor and indicate whether the positive crankcase valve is stuck closed based on an air/fuel ratio in the intake manifold as indicated via the intake air oxygen sensor positioned in the intake manifold. 11. The system of claim 10, wherein the controller further stores instructions in non-transitory memory, that when executed, cause the controller to: indicate an air/fuel ratio in the intake manifold via the intake air oxygen sensor positioned in the intake manifold while the engine is being spun in the reverse direction; andwherein the engine is spun in the forward direction further responsive to an indication of a lean air/fuel ratio in the intake manifold while the engine is being spun in the reverse direction. 12. The system of claim 10, wherein the controller further stores instructions in non-transitory memory, that when executed, cause the controller to: indicate that the positive crankcase valve is stuck open while the engine is being spun in the reverse direction responsive to pressure in the crankcase ventilation tube rising above a predetermined pressure change threshold as indicated via the pressure sensor. 13. The system of claim 10, wherein the controller further stores instructions in non-transitory memory, that when executed, cause the controller to: indicate that the positive crankcase valve is stuck closed while the engine is being spun in the forward direction responsive to an air/fuel ratio in the intake manifold as indicated via the intake air oxygen sensor being below a predetermined air/fuel ratio threshold. 14. The system of claim 10, further comprising: a plurality of fuel injectors configured to deliver fuel to a plurality of engine cylinders;a plurality of spark plugs configured to provide spark to the plurality of engine cylinders; andwherein the controller further stores instructions in non-transitory memory, that when executed, cause the controller to:spin the engine in the reverse direction via the electric motor without delivering fuel to any of the plurality of engine cylinders, and without providing spark to any of the plurality of engine cylinders; andspin the engine in the forward direction via the electric motor while delivering fuel to one or more of the plurality of engine cylinders, but without providing spark to any of the plurality of engine cylinders, such that a portion of fuel injected into the one or more engine cylinders that is not combusted is drawn into the crankcase. 15. The system of claim 10, further comprising: a throttle coupled to the intake manifold; andwherein the controller further stores instructions in non-transitory memory, that when executed, cause the controller to:control the throttle to a position more open than a fully closed position while the engine is being spun in the reverse direction, and control the throttle to a fully open position while the engine is being spun in the forward direction. 16. The system of claim 10, further comprising: a plurality of seat load cells; andwherein the controller further stores instructions in non-transitory memory, that when executed, cause the controller to:prevent the engine from being spun in the reverse direction or the forward direction to determine with the positive crankcase valve is stuck open or stuck closed, responsive to an indication that the vehicle is occupied, as indicated via the plurality of seat load cells. 17. A method comprising: controlling a fluid flow from a crankcase of an engine to an intake manifold of the engine via a positive crankcase ventilation valve positioned in a positive crankcase line;monitoring a pressure in a crankcase ventilation tube connecting the crankcase to an air intake system via a pressure sensor positioned in the crankcase ventilation tube;indicating an air/fuel ratio in the intake manifold via an intake air oxygen sensor;providing fuel and spark to a plurality of engine cylinders via a plurality of fuel injectors and a plurality of spark plugs; andresponsive to conditions being met for conducting a positive crankcase valve diagnostic procedure:spinning the engine unfueled and without spark in a reverse direction and indicating the positive crankcase valve is stuck open responsive to pressure in the crankcase ventilation tube coupling the crankcase to the air intake system being greater than a predetermined pressure threshold; andresponsive to an indication that the positive crankcase valve is not stuck closed and further responsive to an indication of a lean air/fuel ratio in the intake manifold:spinning the engine fueled but without providing spark in a forward direction and indicating the positive crankcase valve is stuck closed responsive to an air/fuel ratio in the intake manifold below a predetermined air/fuel ratio threshold while spinning the engine unfueled in the forward direction. 18. The method of claim 17, wherein conditions being met for the positive crankcase valve diagnostic procedure include a time since a key-off event greater than a predetermined time duration, and a threshold duration of time elapsing since a previously conducted positive crankcase valve diagnostic procedure; wherein a vehicle controller is put into a sleep mode responsive to the key-off event; andwherein the vehicle controller is woken up from the sleep mode responsive to the predetermined time duration elapsing after the key-off event. 19. The method of claim 17, wherein positive pressure with respect to atmospheric pressure is routed from the intake manifold, through the positive crankcase line, through the crankcase, and through the crankcase ventilation tube while spinning the engine unfueled in the reverse direction under conditions wherein the positive crankcase valve is stuck open; and wherein fluid flow is routed from the crankcase, through the positive crankcase line, and to the intake manifold while spinning the engine fueled in the forward direction responsive to the positive crankcase valve not being stuck closed. 20. The method of claim 17, further comprising: controlling an intake air flow to the engine via a throttle upstream of the intake manifold; andcontrolling the throttle to a position greater than a fully closed position while spinning the engine in reverse; andcontrolling the throttle to a fully open position while spinning the engine in the forward direction.
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이 특허에 인용된 특허 (9)
Hewelt James Michael ; Stewart Etsuko Muraji, Crankcase ventilation system diagnostic.
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