IPC분류정보
국가/구분 |
United States(US) Patent
등록
|
국제특허분류(IPC7판) |
|
출원번호 |
US-0014941
(2004-12-20)
|
우선권정보 |
EP-04425023(2004-01-16) |
발명자
/ 주소 |
- Saretto,Roberto
- Vafidis,Costantinos
- Vattaneo,Francesco
|
출원인 / 주소 |
- C.R.F. Societa Consortile per Azioni
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대리인 / 주소 |
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인용정보 |
피인용 횟수 :
0 인용 특허 :
10 |
초록
A multiple cylinder engine is described, provided with an electronically controlled hydraulic system for actuating the intake valves, in which intake valves and exhaust valves are controlled by a single camshaft.
대표청구항
▼
What is claimed is: 1. A multi-cylinder internal combustion engine, comprising: at least an intake valve and at least an exhaust valve for each cylinder, each provided with respective spring return means which thrust the valve towards a closed position, to control respective intake and exhaust cond
What is claimed is: 1. A multi-cylinder internal combustion engine, comprising: at least an intake valve and at least an exhaust valve for each cylinder, each provided with respective spring return means which thrust the valve towards a closed position, to control respective intake and exhaust conduits, at least a camshaft, for actuating the intake valves and the exhaust valves of the engine cylinders by means of respective tappets, in which each intake valve is actuated by the respective tappet, against the action of the aforesaid spring return means, by the interposition of hydraulic means including a pressurized fluid chamber, which is faced by a pumping piston connected to the tappet of the intake valve, said pressurized fluid chamber being able to be connected by means of a solenoid valve with an exhaust channel, in order to uncouple the intake valve from the respective tappet and cause the rapid closure of the valve by effect of the respective spring return means, electronic control means for controlling each solenoid valve in such a way as to vary the time and travel of opening of the respective intake valve as a function of one or more operative parameters of the engine, wherein: both the intake valves and the exhaust valves of the engine are actuated by respective cams carried by a single camshaft of the engine, the exhaust valves of the engine are actuated mechanically by the respective cams of the single camshaft, the intake valves of the engine have the respective pumping pistons actuated by the respective cams of the single camshaft by means of rocker arm members co-operating with said cams of the intake valves, characterized in that pressurized fluid chamber (C) communicates through said solenoid valve (24) with a fluid feeding circuit in which a non return valve (121) is interposed, which allows fluid passage only in the direction of the pressurized fluid chamber (C) and at least a tank (120), vented at its top to the atmosphere located upstream (with reference to the direction of feeding of the fluid) of said check valve (121). 2. An engine as claimed in claim 1, wherein the exhaust valves of the engine are actuated by the respective cams of the single camshaft by means of elements co-operating with said cams on a side of said single camshaft angularly offset relative to the side of said camshaft co-operating with elements for actuating the intake valves. 3. An engine as claimed in claim 1, wherein each cylinder of the engine has at least an intake valve and at least an exhaust valve positioned with their axes in a same plane, orthogonal to the axis of said single camshaft and controlled by respective cams of said single camshaft which are axially distanced from each other. 4. An engine as claimed in claim 3, wherein each pumping piston has the axis contained in a plane that is orthogonal to the axis of the camshaft, which is distanced from said plane containing the axes of the intake valve and of the exhaust valve. 5. An engine as claimed in claim 2, wherein said camshaft co-operates with elements for actuating the intake valves and with elements for actuating the exhaust valves respectively on two sides thereof, mutually offset by an angle of 90째. 6. An engine as claimed in claim 2, wherein said camshaft co-operates with elements for actuating the intake valves and with elements for actuating the exhaust valves respectively on two sides thereof, mutually offset by an angle of about 180째. 7. An engine as claimed in claim 1, wherein the support of the single camshaft, the supports for the aforesaid rocker arm members, the tappets of the intake valves and the elements co-operating with the exhaust valves, as well as the aforesaid hydraulic means for controlling the intake valves and the solenoid valves associated therewith are all borne on a single block mounted on the engine head. 8. An engine as claimed in claim 1, wherein for each outgoing radial direction from the axis of the single camshaft, the radial dimension of the cam actuating the intake valve is smaller than the radial dimension of the cam actuating the exhaust valve. 9. An engine as claimed in claim 1, wherein the aforesaid hydraulic means comprise a piston for actuating each intake valve, slidably mounted in a guide bushing, said actuating piston facing a variable volume chamber communicating with the pressurized fluid chamber both through first communication means controlled by a check valve which allows only the passage of the fluid from the pressurized fluid chamber to the variable volume chamber, and through second communication means which allow the passage between the two chambers in both directions; said hydraulic means further comprising hydraulic braking means able to cause a narrowing of said second communication means in the final phase of closure of the engine valve. 10. An engine as claimed in claim 9, wherein between actuating piston of each intake valve and the stem of the intake valve is interposed a hydraulic tappet. 11. An engine as claimed in claim 10, wherein said hydraulic tapped comprises: a first outer bushing slidably mounted within the guide bushing of the actuating piston and having an end wall in contact with an end of the stem of the intake valve, a second inner bushing slidably mounted within said first outer bushing and having an end in contact with a corresponding end of said actuating piston, a first chamber defined between said bushing and said actuating piston, which is in communication with a passage for feeding the pressurized fluid to said first chamber, a second chamber defined between said first bushing and said second bushing, and a non return valve which controls a passage in a wall of said second bushing to allow the passage of fluid only from said first chamber to said second chamber of said auxiliary hydraulic tappet. 12. An engine as claimed in claim 1, wherein said tank has an inflow channel which ends at its summit and an outflow channel which starts from its bottom. 13. An engine as claimed in claim 1, wherein the cams which actuate the exhaust valves co-operate with tappets that are directly associated to the exhaust valves. 14. An engine as claimed in claim 1, wherein the cams that actuate the exhaust valves actuate said valves by means of rocker arm members mounted oscillating on the engine structure. 15. An engine as claimed in claim 1, wherein said rocker arm members interposed between the cams for actuating the intake valves and the pumping pistons associated with the various intake valves are pivotally engaged centrally and have an end which bears a freely rotating roller co-operating with the respective cam and the opposite end which controls the respective pumping piston. 16. An engine as claimed in claim 1, wherein said rocker arm members interposed between the cams for actuating the intake valves and the pumping pistons associated with the various intake valves have an end which is mounted oscillating on the structure of the engine, an intermediate position that supports in freely rotating fashion a roller co-operating with the respective cam and the opposite end which co-operates with the respective pumping piston.
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