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Valve operating device of internal combustion engine

  • US 6,467,443 B1
  • Filed: 11/09/2000
  • Issued: 10/22/2002
  • Est. Priority Date: 11/29/1999
  • Status: Expired due to Fees
First Claim
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1. A valve operating device of an internal combustion engine, comprising:

  • low and high speed cams coaxially disposed on a cam shaft, said low speed cam having a lobe that is lower than that of said high speed cam;

    a main rocker arm pivotally supported by a rocker shaft and operatively contacting an intake or exhaust valve of the engine to actuate the same;

    first and second sub-rocker arms pivotally supported by said main rocker arm and pivotally actuated by said low and high speed cams respectively;

    a connecting member supported by said main rocker arm, said connecting member comprising first and second engaging portions which are respectively engageable with first and second engaged portions defined by said first and second sub-rocker arms, so that upon engagement of said first engaging portion with said first engaged portion, said first sub-rocker arm and said main rocker arm become fixed to each other to pivot about said rocker shaft like a single unit, and upon engagement of said second engaging portion with said second engaged portion, said second sub-rocker arm and said main rocker arm become fixed to each other to pivot about said rocker shaft like a single unit;

    a hydraulically actuating mechanism comprising first and second hydraulic work chambers, said mechanism inducing the engagement between said first engaging portion and said first engaged portion upon discharge of hydraulic fluid from said first work chamber and inducing a disengagement between said first engaging portion and said first engaged portion upon feeding of the hydraulic fluid into said first work chamber, and said mechanism selectively inducing the engagement or disengagement between said second engaging portion and said second engaged portion in accordance with a pressure of hydraulic fluid fed to said second work chamber;

    a hydraulic pressure producing unit that feeds said first and second work chambers with hydraulic pressure respectively; and

    a control unit that, in accordance with operation condition of the engine, controls said hydraulic pressure producing unit, so that said hydraulically actuating mechanism has at least first, second and third operation modes, said first mode being a mode wherein disengagement takes place both between said first engaging portion and said first engaged portion and between said second engaging portion and said second engaged portion, said second mode being a mode wherein engagement takes place between said first engaging portion and said first engaged portion and disengagement takes place between said second engaging portion and said second engaged portion, said third mode being a mode wherein engagement takes place both between said first engaging portion and said first engaged portion and between said second engaging portion and said second engaged portion, in which said hydraulically actuating mechanism further comprises first and second pistons which are operatively received in said first and second hydraulic work chambers, said first piston bringing said first engaging portion into engagement with said first engaged portion when assuming its projected position in response to discharge of hydraulic fluid from said first work chamber and said second piston bringing said second engaging portion into engagement with said second engaged portion when assuming its projected position in response to feeding of hydraulic fluid into said second work chamber, and in which a biasing spring is disposed in said first work chamber to bias said first piston toward the projected position.

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