IPC분류정보
국가/구분 |
United States(US) Patent
등록
|
국제특허분류(IPC7판) |
|
출원번호 |
US-0442433
(2006-05-26)
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등록번호 |
US-7503297
(2009-03-17)
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우선권정보 |
JP-2005-154325(2005-05-26) |
발명자
/ 주소 |
- Fujita,Hideo
- Suzuki,Atsushi
|
출원인 / 주소 |
|
대리인 / 주소 |
Knobbe, Martens, Olson & Bear, LLP.
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인용정보 |
피인용 횟수 :
1 인용 특허 :
18 |
초록
▼
A valve drive mechanism for an engine can include a drive shaft that is configured for rotation about an axis. A valve member is configured to be driven by the rotation of the drive shaft to open and close a valve. A variable valve timing mechanism is positioned at least partially between the valve
A valve drive mechanism for an engine can include a drive shaft that is configured for rotation about an axis. A valve member is configured to be driven by the rotation of the drive shaft to open and close a valve. A variable valve timing mechanism is positioned at least partially between the valve member and the drive shaft. The variable valve timing mechanism is configured to vary a valve open period of the valve. The valve drive mechanism is configured such that, during a specific operation range, the valve open period includes a main valve open period during which the valve is open in a suction or exhaust stroke, and a sub valve open period during which the valve is open in an expansion or compression stroke.
대표청구항
▼
What is claimed is: 1. A valve drive mechanism for an engine, the valve drive mechanism comprising: a drive shaft that is configured for rotation about an axis; a valve member that is configured to be driven by the rotation of the drive shaft to open and close a valve; and a variable valve mechanis
What is claimed is: 1. A valve drive mechanism for an engine, the valve drive mechanism comprising: a drive shaft that is configured for rotation about an axis; a valve member that is configured to be driven by the rotation of the drive shaft to open and close a valve; and a variable valve mechanism positioned at least partially between the valve member and the drive shaft, the variable valve mechanism configured to vary a valve open period of the valve; wherein the variable valve mechanism is configured such that, during a specific operation range, the valve open period includes a main valve open period during which the valve is open in a suction or exhaust stroke, and a sub valve open period during which the valve is open in an expansion or compression stroke; wherein the variable valve mechanism comprises a rocker cam having a main lift portion on one end and a sub lift portion on an opposite end, the main lift portion configured to engage the valve member during the main valve open period, and the sub lift portion configured to engage the valve member during the sub valve open period. 2. The valve drive mechanism of claim 1, wherein the valve is an intake valve. 3. The valve drive mechanism of claim 2, wherein the specific operation range corresponds to when the engine is starting and wherein during the main valve open period the intake valve is open in the suction stroke and during the sub valve open period the intake valve is open in the expansion stroke. 4. The valve drive mechanism of claim 3, wherein during the sub valve open period combustion gas or unburned gas flows into an intake system during the expansion stroke. 5. The valve drive mechanism of claim 1, wherein the valve is an exhaust valve. 6. The valve drive mechanism of claim 5, wherein the specific operation range corresponds to when the engine is starting and wherein during the main valve open period the exhaust valve is open during the exhaust stroke and during the sub valve open period the exhaust valve is open in the compression stroke. 7. The valve drive mechanism of claim 6, wherein during the sub valve open period a mixture flows into an exhaust system during the compression stroke. 8. The valve drive mechanism of claim 7, further comprising an intake valve mechanism comprising: a second drive shaft that is configured for rotation about a second axis; a intake valve member that is configured to be driven by the rotation of the drive shaft to open and close an intake valve; and a intake variable valve mechanism positioned at least partially between the intake valve member and the second drive shaft, the intake variable valve drive mechanism is configured to vary an intake valve open period of the intake valve; wherein the intake variable valve mechanism is configured such that, during a specific operation range, the intake valve open period includes a main intake valve open period during which the intake valve is open in the suction stroke, and a sub intake valve open period during which the intake valve is open in the expansion stroke. 9. The valve drive mechanism of claim 5, wherein the specific operation range corresponds to an idling operation range and wherein during the main valve open period the exhaust valve is opened in the exhaust stroke and during the sub valve open period the exhaust valve is open in the compression stroke. 10. The valve drive mechanism of claim 9, wherein during the sub valve open period a mixture flows into an exhaust system during the compression stroke. 11. The valve drive mechanism of claim 1, wherein the drive shaft is an exhaust camshaft that is rotationally supported, the valve member comprises a rocker arm supported for rocking motion, the variable valve mechanism comprises: a rocker cam supported for rocking motion and configured to be driven by the exhaust camshaft, and an intermediate rocker rockably that is interposed between a cam face of the rocker cam and the rocker arm; the intermediate rocker is pressed with the cam face as the rocker cam rocks to rock the rocker arm, and the open period and the lift amount of the exhaust valve is made continuously controllable by changing relative positional relationship between the intermediate rocker and the cam face. 12. The valve drive mechanism of claim 11, wherein the cam face of the rocker cam comprises: a base circle portion, a main lift portion continuous on a fore-end side of the base circle portion, and a sub lift portion formed on a root end side of the base circle portion; a cam nose portion of the exhaust camshaft has a sub nose portion for driving the intermediate rocker in the opening direction using the sub lift portion of the cam face, to bring about the sub valve open period of the exhaust valve in the compression stroke. 13. A valve drive mechanism for an engine, the valve drive mechanism comprising: a drive shaft that is configured for rotation about an axis; a valve member that is configured to be driven by the rotation of the drive shaft to open and close a valve; and a variable valve mechanism positioned at least partially between the valve member and the drive shaft, the variable valve mechanism configured to vary a valve open period of the valve; wherein the variable valve mechanism is configured such that, during a specific operation range, the valve open period includes a main valve open period during which the valve is open in a suction or exhaust stroke, and a sub valve open period during which the valve is open in an expansion or compression stroke; wherein the drive shaft is an intake camshaft, the valve member comprises a rocker arm supported for rocking motion on a shaft, the variable valve mechanism comprises a rocker cam that is supported for rocking motion and is configured to be driven by the intake camshaft, and an intermediate rocker rockably interposed between a cam face of the rocker cam and the rocker arm; the intermediate rocker configured to be pressed with the cam face as the rocker cam rocks to rock the rocker arm, and the open period and the lift amount of the intake valve is made continuously controllable by changing relative positional relationship between the intermediate rocker and the cam face. 14. The valve drive mechanism of claim 13, wherein the cam face of the rocker cam comprises: a base circle portion, a main lift portion continuous on a fore-end side of the base circle portion, and a sub lift portion formed on a root end side of the base circle portion; a cam nose portion of the intake camshaft has a sub nose portion for driving the intermediate rocker in the opening direction using the sub lift portion of the cam face, to bring about the sub valve open period of the intake valve in the expansion stroke. 15. A valve drive mechanism for an engine, the valve drive mechanism comprising: a drive shaft that is configured for rotation about an axis; a valve member that is configured to be driven by the rotation of the drive shaft to open and close a valve; a variable valve mechanism positioned at least partially between the valve member and the drive shaft, the variable valve mechanism configured to continuously vary a valve open period of the valve; and means for opening the valve in a suction or exhaust stroke for a first period of time and opening the valve in an expansion or compression stroke for a second period of time that is smaller than the first period of time wherein the variable valve mechanism comprises a rocker cam having a main lift portion on one end and a sub lift portion on an opposite end, the main lift portion configured to engage the valve member during the main valve open period, and the sub lift portion configured to engage the valve member during the sub valve open period. 16. The valve drive mechanism of claim 15, wherein the valve is an intake valve. 17. The valve drive mechanism of claim 16, wherein the first time period is during the suction stroke and the second time period is during in the expansion stroke. 18. The valve drive mechanism of claim 15, wherein the valve is an exhaust valve. 19. The valve drive mechanism of claim 18, wherein during the first time period is during the exhaust stroke and the second time period is during the compression stroke. 20. A method of operating a four-cycle internal combustion engine comprising: during a first operating condition, operating the internal combustion engine through a combustion cycle comprising a suction stroke, a compression stroke, an expansion stroke, and an exhaust stroke; during the combustion cycle, opening a valve during the suction or the exhaust stroke for a first period of time and then substantially closing the valve; and during the same combustion cycle, opening the same valve during an expansion or compression stroke for a second period of time and then substantially closing the valve; wherein the valve is opened and closed using a variable valve mechanism, the variable valve mechanism comprising a rocker cam having a main lift portion on one end and a sub lift portion on an opposite end, the main lift portion configured to engage the valve member during the first period of time, and the sub lift portion configured to engage the valve member during the second period of time. 21. The method of claim 20, wherein the second period of time is less than the first period of time. 22. The method of claim 20, wherein the step of opening the valve during the suction or exhaust stroke for a first period of time comprises opening an intake valve during the suction stroke. 23. The method of claim 22, wherein the step of opening the same valve during the expansion or compression stroke for a second period of time comprises opening the intake valve during the expansion stroke. 24. The method of claim 20, wherein the step of opening the valve during the suction or exhaust stroke for a first period of time comprises opening an exhaust valve during the exhaust stroke. 25. The method of claim 24, wherein the step of opening the same valve during the expansion or compression stroke for a second period of time comprises opening the exhaust valve during the compression stroke. 26. A method of operating a four-cycle internal combustion engine comprising: during a first operating condition, operating the internal combustion engine through a combustion cycle comprising a suction stroke, a compression stroke, an expansion stroke, and an exhaust stroke; during the combustion cycle, opening a valve during the suction or the exhaust stroke for a first period of time and then substantially closing the valve; during the same combustion cycle, opening the same valve during an expansion or compression stroke for a second period of time and then substantially closing the valve; and further comprising, during a second operating condition, operating the internal combustion engine through a second combustion cycle comprising a suction stroke, a compression stroke, an expansion stroke, and an exhaust stroke, opening the valve during the suction or exhaust stroke for the third period of time and not opening the same valve during an expansion or compression stroke. 27. The method of claim 26, wherein operating the first operating conditions corresponds to a condition in which the internal combustion engine is starting. 28. A method of operating a four-cycle internal combustion engine comprising: during a first operating condition, operating the internal combustion engine through a combustion cycle comprising a suction stroke, a compression stroke, an expansion stroke, and an exhaust stroke; during the combustion cycle, opening a valve during the suction or the exhaust stroke for a first period of time and then substantially closing the valve; during the same combustion cycle, opening the same valve during an expansion or compression stroke for a second period of time and then substantially closing the valve; and wherein operating the first operating conditions corresponds to a condition in which the internal combustion engine is idling.
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