Internal-combustion engines – Poppet valve operating mechanism – With means for varying timing
Reexamination Certificate
2000-07-14
2001-10-16
Lo, Weilun (Department: 3748)
Internal-combustion engines
Poppet valve operating mechanism
With means for varying timing
C123S090170, C123S090330, C123S090380
Reexamination Certificate
active
06302071
ABSTRACT:
BACKGROUND OF THE INVENTION
The present invention relates to a valve moving control apparatus having a hydraulic valve phase variable mechanism for altering phase or opening-closing time of at least one of a suction valve and an exhaust valve provided in a cylinder head of an internal combustion engine, particularly to an oil passage system for operating the valve phase variable mechanism.
Hitherto, a valve moving control apparatus for an internal combustion engine having a hydraulic connection changing mechanism has been known (Japanese Utility Model Publication Hei 6-6166). In this connection changing mechanism, in order to change connection and disconnection of a plurality of rocker arms which drive a suction valve or an exhaust valve to open, a changing valve is provided in an oil pressure supply passage.
The oil pressure supply passage leading to an oil pressure supply source has a horizontal passage section in which a small diameter part near the changing valve and a large diameter part connected to the small diameter part through a step are provided. Therefore, even if a relatively large quantity of working oil flows out from the oil pressure supply passage owing to operation of the changing valve, temporary pressure lowering in the oil pressure passage can be restrained by pressure accumulating effect of the large diameter part.
The large diameter part has a function to somewhat decrease pulsation of working oil pressure occurring in the oil pressure supply passage as well as the pressure accumulating function. In order to sufficiently decrease the pulsation of working oil pressure at the large diameter part, it is necessary to further enlarge the diameter of the large diameter part or to lengthen the passage length of the enlarged large diameter part. However, since a supporting section for the rocker shaft and a cooling water passage are formed in the neighborhood of the large diameter part for example, it is difficult to enlarge the diameter of the large diameter part or lengthen the passage length, and therefore the pulsation decreasing function of the large diameter part is limited.
SUMMARY OF THE INVENTION
The present invention has been accomplished in view of the foregoing, and an object of the invention is to decrease or extinguish pressure pulsation of working oil supplied to an oil pressure control valve for controlling operation of a hydraulic valve phase variable mechanism to stabilize operation of the valve phase variable mechanism.
The present invention provides an oil passage system of a valve moving control apparatus for an internal combustion engine, comprising: a hydraulic valve phase variable mechanism for altering phase of at least one of a suction valve and an exhaust valve provided in a cylinder head; a working oil supply passage communicating with a working oil supply source; a phase operating oil passage communicating with the working oil supply passage; an oil pressure control valve communicating with the phase operating oil passage for controlling pressure of a phase operating oil supplied from the working oil supply passage through the phase operating oil passage to produce a phase controlling oil; and a phase controlling oil passage between the oil pressure control valve and the valve phase variable mechanism for supplying the phase controlling oil to the valve phase variable mechanism to alter the phase in accordance with pressure of the phase controlling oil by the valve phase variable mechanism, wherein the phase operating oil passage has a reversing section where flow direction of the phase controlling oil is altered in reverse.
According to this invention, by providing the reversing section in the phase operating oil passage, a relatively long phase operating oil passage can be formed within the cylinder head having a limited dimension, so that the phase operating oil flows through the long phase operating oil passage reversing at the reversing section. As the result, pressure pulsation which is produced at the working oil supply passage and accompanied by the phase operating oil is decreased or extinguished when the phase operating oil passes through the phase operating oil passage, and a phase operating oil of stable pressure having little pulsation is supplied to the oil pressure control valve. Therefore, pressure of the phase controlling oil flowing out of the oil pressure control valve is also stabilized and a stable operation of the valve phase variable mechanism can be realized.
Since the phase operating oil passage is reversed at the reversing section, a relatively long phase operating oil passage can be formed in the cylinder head having cooling water passages and various member supporting section letting pass through relatively narrow portion. Namely, a structure for preventing pressure pulsation of the oil for operating the valve phase variable mechanism can be provide without influencing various passages and member supporting sections already having been formed in the cylinder head.
According to another aspect of the present invention, there is provided an oil passage system of a valve moving control apparatus for an internal combustion engine, comprising: a hydraulic valve phase variable mechanism for altering phase of at least one of a suction valve and an exhaust valve provided in a cylinder head; a hydraulic valve characteristic changing mechanism for changing valve operational characteristic of at least one of the suction valve and the exhaust valve; an oil pressure control valve; an oil pressure changing valve; a working oil supply passage communicating with a working oil supply source; a phase operating oil passage leading to the oil pressure control valve from the working oil supply passage; a change operating oil passage leading to the oil pressure changing valve from the working oil supply passage; a phase controlling oil passage leading to the valve phase variable mechanism from the oil pressure control valve; and a change controlling oil passage leading to the valve characteristic changing mechanism from the oil pressure changing valve, the oil pressure control valve controlling pressure of a phase operating oil supplied from the working oil supply passage through the phase operating oil passage to produce a phase controlling oil to be supplied to the valve phase variable mechanism which alters the phase in accordance with pressure of the phase controlling oil, the oil pressure changing valve changing pressure of a change operating oil supplied from the working oil supply passage through the change operating oil passage to produce a change operating oil to be supplied through the change controlling oil passage to the valve characteristic changing mechanism which changes the valve operational characteristic in accordance with pressure of the change controlling oil, wherein the working oil supply passage is arranged at a suction side or an exhaust side of the cylinder head, the phase operating oil passage is connected to the working oil supply passage at a downstream position or a neighborhood of a position where the change operating oil passage branches off from the working oil supply passage, and the phase operating oil passage formed in the cylinder head has a reversing section where flow direction of the phase operating oil is altered in reverse disposed at the exhaust side or the suction side.
The latter oil passage system exhibits the same effect as that of the former oil passage system. Moreover, since the phase operating oil passage extends from the working oil supply passage provided at a suction side or an exhaust side of the cylinder head to the oil pressure control valve through the reversing section provided at another side (the exhaust side or the suction side) of the cylinder head, the phase operating oil passage is made long utilizing size of the cylinder head between the suction side and the exhaust side, and the phase operating oil passes through this long phase operating oil passage from the working oil supply passage to the oil pressure control valve.
If a relatively large quantity of the worki
Arent Fox Kintner & Plotkin & Kahn, PLLC
Honda Giken Kogyo Kabushiki Kaisha
Lo Weilun
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