Internal-combustion engines – Poppet valve operating mechanism – With means for varying timing
Reexamination Certificate
2001-01-17
2002-02-12
Lo, Weilun (Department: 3748)
Internal-combustion engines
Poppet valve operating mechanism
With means for varying timing
C123S090170, C074S56800M, C464S002000
Reexamination Certificate
active
06345595
ABSTRACT:
BACKGROUND OF THE INVENTION
a) Field of the Invention
The present invention relates to a control apparatus for a variably operated engine valve mechanism which variably controls a valve displacement or an open-and-closure timing of an engine valve of an intake or exhaust valve of an internal combustion engine.
b) Description of the Related Art
A Japanese Patent Application First Publication No. Heisei 9-60507 published on Mar. 4, 1997 exemplifies a previously proposed engine valve (intake valve) open-and-closure timing regulating apparatus.
The disclosed engine valve open-and-closure timing Regulating apparatus is of a vane type. In the disclosed engine valve open-and-closure timing regulating apparatus, a vane fixed on an end of a camshaft is rotatably housed within a cylindrical housing of a timing pulley whose opening end is enclosed with a front cover and a rear cover. An advance angle side oil chamber and a retardation angle side oil chamber are defined between two partitioning walls and two blade sections of the vane. The two partitioning walls are of substantially two trapezoid shapes projected mutually from the diameter direction on an inner peripheral surface of the housing.
In addition, an oil pressure drained from an oil pump rotationally driven with a motor is supplied selectively with a motor is supplied selectively with an electromagnetic switch valve to one of advance angle side oil pressure chamber or a retardation angle side pressure chamber by the change of flow passages. Then, the drive of pressure causes the vane to be rotated in a normal or reverse direction so that a relative rotation phase between the timing pulley and the cam shaft is varied and the open-and-closure timing of the intake valve is variably regulated.
SUMMARY OF THE INVENTION
However, in the previously proposed open-and-closure timing control apparatus, in order to supply the oil pressure selectively to each of the advance and retardation angle side oil chambers, a flow passage of working oil drained from the oil pump is merely switched using the electromagnetic switching valve.
Hence, an energy loss in the oil pump occurs. That is to say, even after the working oil is supplied to one of the advance and retardation angle side oil chambers from the flow passage switched by the electromagnetic switching valve so that the vane is held at a rotation position of a maximum advance angle side or a maximum retardation angle side. The oil pump is always revolved in the same direction to perform a continuous draining action. An extra working oil drained is exhausted directly from a drain passage.
Consequently, the energy loss in the oil pump is generated and a reduction of the energy efficiency occurs.
In addition, a high cost electromagnetic switching valve is used for the switch of the flow passage, a high manufacturing cost of the whole regulating apparatus will be resulted.
It is an object of the present invention to provide a control apparatus for a variably operated engine valve mechanism which can solve the above-described problems, i.e., the reduction of the energy loss in the oil pump and no use of the expensive electromagnetic switching valve.
According to one aspect of the present invention, there is provided a control apparatus for a variably operated engine valve mechanism for an internal combustion engine, comprising: a phase converter to variably control at least one of a displacement and an open-and-closure timing of an engine valve; an oil pump to supply a hydraulic to operate the phase converter; a reversible motor to drivingly revolve the oil pump; and a controller to output a drive current to the reversible motor according to an engine driving condition, the controller controlling a revolution direction of the oil pump via the reversible motor at least when an operation of the phase converter is switched.
This summary of the invention does not necessarily describe all necessary features so that the invention may also be a sub-combination of these described features.
REFERENCES:
patent: 4517934 (1985-05-01), Papez
patent: 4862845 (1989-09-01), Butterfield et al.
patent: 5557983 (1996-09-01), Hara et al.
patent: 5680837 (1997-10-01), Pierik
patent: 5860328 (1999-01-01), Regueiro
patent: 5915348 (1999-06-01), Scheidt et al.
patent: 6129062 (2000-10-01), Koda
patent: 6234125 (2001-05-01), Neubauer et al.
patent: 9-060507 (1997-03-01), None
patent: 11-117719 (1999-04-01), None
U.S. application No. 09/414,640, Torii et al., filed Oct. 8, 1999.
Foley & Lardner
Lo Weilun
Unisia Jecs Corporation
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