Variable valve actuation apparatus for internal combustion engine
Inactive Publication Date: 2012-03-08
TOYOTA JIDOSHA KK
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- Summary
- Abstract
- Description
- Claims
- Application Information
AI Technical Summary
Benefits of technology
[0006]The invention provides a variable valve actuation apparatus for an internal combustion engine which reduces the inertia of a member that is driven by an actuator and reduces the friction that occurs on the member, and which favorably switches the opening characteristic of valves that are provided for at least two cylinders of the engine in association with motion performed by the actuator.
[0008]According to the first aspect of the invention, since the main displacement member and the member-linked shaft is linked together in such a manner that relative rotation therebetween is possible, the main displacement member rotates alone without involving rotation of the member-linked shaft, when the actuator operates so as to engage the engagement portion of the main displacement member with the guide rail. Therefore, according to the first aspect, it becomes possible to reduce the inertia of the member that is driven by the actuator and reduce the friction force that occurs on the member, and to favorably switch the opening characteristic of valves that are provided for at least two cylinders in association with motion performed by the actuator.
[0010]Therefore, due to the construction provided in the first aspect, the inertia of the member that is driven by the actuator can be reduced, and the friction force that occurs on the member can be reduced. Besides, the state of motion of the transfer member of each cylinder can be changed through the utilization of the displacement of the main displacement member and the displacement of the subsidiary displacement member that is in operative connection with the displacement of the main displacement member.
[0012]According to the foregoing construction, in a variable valve actuation apparatus of a type that switches between the state in which the first rocker arm and the second rocker arm are linked together and the unlinked state in which the linkage therebetween is removed, by utilizing the displacement of the switch pin, it becomes possible to reduce the inertia of the member that is driven by the actuator and reduce the friction force that occurs on the member and to switch between the foregoing linked state and the unlinked state.
[0014]According to this construction, by effectively utilizing the space present over the cylinder head of the internal combustion engine, it is possible to improve the mountability of the variable valve actuation apparatus on the internal combustion engine, in comparison with a construction in which the member-linked shaft is supported by a member that is separate from the rocker shaft.
[0018]According to the foregoing construction, due to the engagement between the groove formed in the member-linked shaft and the pin that penetrates the main displacement member, it is possible to favorably realize the linkage between the main displacement member and the member-linked shaft in a manner that allows relative rotation between the main displacement member and the member-linked shaft but constrains relative movement therebetween in the axis direction.
Problems solved by technology
By the way, in the variable valve actuation apparatus of an internal combustion engine, when the opening characteristic of valves is switched in association with an motion performed by an actuator, the actuator's drive force needed in order to drive a member that is driven by the actuator becomes inconveniently large if the inertia of the member is large, or if the friction force that occurs on the member when the actuator drives the member is large.
Method used
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Embodiment Construction
[0024]EMBODIMENT 1. Hereinafter, Embodiment 1 of the invention will be described with reference to FIG. 1 to FIG. 4. [CONSTRUCTION OF VARIABLE VALVE ACTUATION APPARATUS] (BASIC
[0025]CONSTRUCTION OF VARIABLE VALVE ACTUATION APPARATUS) FIG. 1 is a perspective view showing a variable valve actuation apparatus 10 for an internal combustion engine 1 according to Embodiment 1 of the invention. Incidentally, in FIG. 1, the illustration of a later-described camshaft 18 is omitted. Besides, although FIG. 1 shows only two cylinders (cylinders No. 1 and No. 2) while omitting the illustration of other cylinders and the like, the internal combustion engine 1 of Embodiment 1 is, for example, an in-line four-cylinder engine that has four cylinders (No. 1 to No. 4). Besides, each cylinder of the internal combustion engine 1 is provided with two intake valves and two exhaust valves. The variable valve actuation apparatus 10 functions as an apparatus that drives two intake valves or two exhaust valve...
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A variable valve actuation apparatus for an internal combustion engine includes a first link arm which has a projected portion that is engageable with and disengageable from a guide rail, and which is displaceable in the axis direction of a camshaft, and a link shaft linked to the first link arm in such a manner as to allow rotation but constrain movement in the axis direction. When an electro-magnetic solenoid is electrified, the first link arm rotates about the link shaft so that the projected portion engages with the guide rail. In association with the displacement of the link arms that occurs during the engagement, the state of motion of second rocker arms changes, so that the opening characteristic of valves provided for each cylinder is switched.
Description
BACKGROUND OF THE INVENTION[0001]1. Field of the Invention[0002]The invention relates to a variable valve actuation apparatus for an internal combustion engine.[0003]2. Description of the Related Art[0004]Japanese Patent Application Publication No. 6-33714 (JP-A-6-33714), for example, discloses a variable valve actuation apparatus for an internal combustion engine. This related-art variable valve actuation apparatus includes an intake or exhaust valve, a low-speed cam, a high-speed cam, a main rocker arm that is drivable by the low-speed cam and that drives the intake valve or the exhaust valve, and a sub-rocker arm that is driven by the high-speed cam. Furthermore, the variable valve actuation apparatus includes a hydraulic piston mechanism as mode switch means for switching between a non-coordination mode in which the sub-rocker arm is not coordinated with the main rocker arm and a coordination mode in which the sub-rocker arm is coordinated with the main rocker arm.[0005]By the w...
Claims
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Patent Timeline
Login to View More IPC IPC(8): F01L1/34
CPCF01L1/185F01L1/267F01L2820/031F01L13/0036F01L2013/0052F01L13/0005F01L13/00F01L1/26F01L1/18
InventorKIDOOKA, AKIO
OwnerTOYOTA JIDOSHA KK