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Variable Valve Apparatus

a valve apparatus and variable technology, applied in non-mechanical valves, valve arrangements, machines/engines, etc., can solve the problems of affecting the operation of the valve, so as to reduce the likelihood of valve-piston interference, reduce the amount of electric power, and reduce the driving torque of the camshaft

Inactive Publication Date: 2010-04-15
TOYOTA JIDOSHA KK
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  • Summary
  • Abstract
  • Description
  • Claims
  • Application Information

AI Technical Summary

Benefits of technology

The present invention provides a variable valve apparatus that uses a motor to drive a camshaft including a cam for pushing a valve biased in the closing direction thereof by a valve spring. The apparatus is designed to resolve interference between the valve and piston in case of an abnormality. The apparatus includes a valve lifter that abuts the cam between the cam and the valve, and the valve lifter has a top face formed such that the direction of a tangential line to a nose tip of the cam inclines with respect to the direction perpendicular to the axial line of the valve stem. The apparatus can also include an electric power supply control means for stopping supply of electric power to the motor when a command value assigned to the motor reaches a predetermined value. Additionally, the apparatus can include a torque reduction mechanism that generates a reduced torque for reduction in a driving torque of the camshaft.

Problems solved by technology

If this situation happens, interference is likely to occur between the valve remaining stopped in the maximum lift state, and the piston continuing a reciprocating motion.
In the type of variable valve apparatus that uses a motor to rotationally drive a camshaft, if the evacuation control mechanism as used in the above conventional valve-driving system, that is, the mechanism for stopping the opening / closing of the valve or for switching to the low-lift cam, is equipped only to avoid the above interference, this will complicate the system configuration uselessly.
In addition, in the type that employs the above evacuation control mechanism, after the error in the synchronous control of the camshaft and crankshaft speeds, the valve-piston interference could occur during the period of switching to the evacuation control.

Method used

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Examples

Experimental program
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Effect test

first embodiment

[Variable Valve Apparatus Configuration]

[0050]Hereinafter, a basic configuration of a variable valve system 10 according to a first embodiment of the present invention will be described referring to FIGS. 1 to 3.

[0051]FIG. 1 is a perspective view showing the configuration of the variable valve apparatus 10 according to the first embodiment of the present invention. The variable valve apparatus 10 shown in FIG. 1 is an apparatus for driving a valve of an internal combustion engine. The system configuration here assumes that the internal combustion engine is constructed as a straight four-cylinder engine. Reference numbers #1 to #4 in FIG. 1 denote first to fourth cylinders, respectively, of the internal combustion engine. The system also assumes that as in a general internal combustion engine, the explosion stroke of the internal combustion engine is sequentially performed in cylinders #1, #3, #4, and #2 in the order named. In addition, the present embodiment assumes that the variabl...

second embodiment

[0087]Next, a second embodiment of the present invention is described below referring to FIG. 8.

[0088]An apparatus according to the present embodiment can be implemented by using the hardware configurations shown in FIGS. 1 to 3 and 5, and making the ECU 40 execute the routine shown in FIG. 8 described later herein.

Feature Sections of the Second Embodiment

[0089]If an abnormality that has been caused to the variable valve apparatus 10 is of a mode that completely powers off the motor, adoption of the above-described configuration shown in FIG. 5 allows interference between the valve 12 and the piston to be avoided reliably, since the cam 18 or the like is rotated by valve spring repulsion. The mode of the abnormality, however, could be such that instead of the motor being completely powered off, the force for driving the cam 18 remains in the motor. If this state actually happens, the valve 12 will stop in a lifted condition since the driving torque of the camshaft 22 by the motor a...

third embodiment

[0096]Next, a third embodiment of the present embodiment is described below with reference to FIGS. 9 to 11.

[0097]FIGS. 9(A) and 9(B) are diagrams illustrating a configuration of a torque reduction mechanism 52 in a variable valve apparatus 50 according to the third embodiment of the present invention. More specifically, FIG. 9(A) shows the variable valve apparatus 50 existing when viewed from the axial direction of the camshaft 22, and FIG. 9(B) shows the variable valve apparatus 50 existing when viewed from the direction of arrow A in FIG. 9(A). In FIG. 9, the same constituent elements as those shown in FIG. 1, are each assigned the same reference number, with their description omitted or simplified.

[0098]The variable valve apparatus 50 of the present embodiment is constructed similarly to the variable valve apparatus 10 of the first embodiment, except that the apparatus 50 includes the torque reduction mechanism 52 shown in FIG. 9. The torque reduction mechanism 52 is a reduced-t...

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PUM

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Abstract

A motor 30 or the like is used to drive a camshaft 22 or the like having a cam 18 or the like to push a valve 12 biased in the closing direction of the valve by a valve spring 17. Between the cam 18 or the like and the valve 12 is present a valve lifter 16 that abuts the cam 18 or the like. The valve lifter 16 includes a top face 16a formed so that when viewed from the axial direction of the camshaft 22 or the like, a tangential direction to the nose tip 18c of the cam 18 or the like inclines with respect to the direction perpendicular to the axial line of a valve stem 14.

Description

TECHNICAL FIELD [0001]The present invention relates to a variable valve apparatus that drives a valve of an internal combustion engine.BACKGROUND ART[0002]Referring to conventional techniques, Patent Document 1, for example, discloses an internal combustion engine that includes a valve-driving system using a motor to drive the opening and closing of a valve. If an error in the synchronous control of camshaft and crankshaft speeds occurs in this conventional valve-driving system, evacuation driving becomes possible by stopping the opening / closing of the valve by use of a lost-motion mechanism or by switching to a low-lift cam for driving the valve at a smaller amount of lift.[0003]Including the above-mentioned document, the applicant is aware of the following documents as a related art of the present invention.[0004][Patent Document 1] Japanese Laid-open Patent Application Publication No. 2005-54732[0005][Patent Document 2] Japanese Laid-open Utility Model Application Publication No....

Claims

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Application Information

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Patent Type & Authority Applications(United States)
IPC IPC(8): F01L1/34
CPCF01L1/0532F01L2009/0411F01L1/143F01L9/22
Inventor KIDOOKA, AKIOEZAKI, SHUICHI
Owner TOYOTA JIDOSHA KK