Method and apparatus for hydraulic clip and reset of engine brake systems utilizing lost motion
AssigneeDiesel Engine Retarders, Inc.
InventorsRobb Janak, Stephen Lak, Michael Bergmann
Life of this patent
Estimating the term…
Abstract
An internal combustion engine may include a hydraulic linkage used to transfer motion from a valve train element, such as a cam, to an engine valve. Method and apparatus for selectively limiting the motion transferred by the hydraulic linkage from the valve train element to the engine valve are disclosed. The motion transferred by the hydraulic linkage may be limited by a means for resetting or clipping that is integrated into the rocker arm/shaft assembly provided in the valve train.
Claims38
An engine braking system, for providing a compression release valve event in an internal combustion engine, comprising:
- a rocker arm shaft;
- a hydraulic relief passage formed in the rocker arm shaft;
- a rocker arm having a central bore adapted to receive the rocker arm shaft, a piston bore, and an internal hydraulic passage connecting the piston bore to a surface port at the central bore;
- means for pivoting the rocker arm on the rocker arm shaft to provide a compression release valve event;
- and
- a lash piston disposed in a piston bore in the rocker arm, said lash piston being adapted to open an engine valve for the compression release event;
- wherein selective hydraulic communication between the hydraulic relief passage and the internal hydraulic passage at the surface port is adapted to release hydraulic fluid from the piston bore.
An engine braking system, for providing a compression release valve event in an internal combustion engine, comprising:
- a first rocker arm having a piston bore and an internal hydraulic passage connecting the piston bore to a surface port on the first rocker arm;
- an adjacent member to the first rocker arm selected from the group consisting of:
- a rocker arm shaft, a rocker arm shaft pedestal, a second rocker arm, a sleeve, a ring, and a follower arm;
- an hydraulic relief opening formed in the adjacent member;
- means for pivoting the rocker arm to provide a compression release valve event;
- and
- an expandable hydraulic tappet disposed in the piston bore in the rocker arm, said tappet being adapted to open an engine valve for the compression release event;
- wherein selective hydraulic communication between the hydraulic relief opening and the internal hydraulic passage at the surface port is adapted to release hydraulic fluid from the piston bore.
An engine braking system for providing a compression release valve event in an internal combustion engine, comprising:
- a rocker arm shaft;
- a hydraulic passage formed in the rocker arm shaft, said relief passage communicating with an outer surface of the rocker arm shaft;
- a rocker arm having a central bore adapted to receive the rocker arm shaft;
- means for pivoting the rocker arm on the rocker arm shaft to provide a compression release valve event;
- an expandable hydraulic tappet disposed in a piston bore in the rocker arm, said tappet being adapted to open an engine valve for the compression release event;
- means for providing hydraulic fluid to the tappet;
- and
- means for providing selective hydraulic communication between the tappet and the relief passage responsive to pivoting of the rocker arm,
- wherein the means for providing hydraulic fluid to the tappet comprises a control valve provided in a control valve bore in the rocker arm first passage formed in the rocker arm and a first passage extending between the piston bore and the control valve bore, and
- wherein the means for providing selective hydraulic communication between the relief passage and the tappet comprises a second passage formed in the rocker arm extending between the first passage and the central bore.
An engine braking system, for providing an engine valve actuation event in an internal combustion engine, comprising:
- a rocker arm shaft;
- a rocker arm mounted on the rocker arm shaft, said rocker arm including a piston bore, a control valve bore, an accumulator bore, a first hydraulic passage connecting the piston bore to the control valve bore, a second hydraulic passage connecting an upper portion of the control valve bore to the accumulator bore, and a third hydraulic passage connecting a lower portion of the control valve bore to a central portion of the second hydraulic passage;
- a control valve slidably disposed in the control valve bore;
- a lash piston slidably disposed in the piston bore;
- and
- an accumulator piston disposed in the accumulator bore.
An engine braking system, for providing a compression release valve event in an internal combustion engine, comprising:
- a first rocker arm having a piston bore and an internal hydraulic passage connecting the piston bore to a surface port on the first rocker arm;
- an adjacent member to the first rocker arm selected from the group consisting of:
- a rocker arm shaft, a rocker arm pedestal, a second rocker arm, a sleeve, a ring, and a follower arm;
- a hydraulic relief opening formed in the adjacent member;
- means for pivoting the rocker arm to provide a compression release valve event;
- and
- a lash piston disposed in the piston bore in the rocker arm, said lash piston being adapted to open an engine valve for the compression release event;
- wherein selective hydraulic communication between the hydraulic relief opening and the internal hydraulic passage at the surface port is adapted to release hydraulic fluid from the piston bore.
A method of providing engine braking in an internal combustion engine using a rocker arm having a hydraulic lash piston integrated in an end of the rocker arm, said method comprising the steps of:
- providing the rocker arm next to an adjacent member selected from the group consisting of:
- a rocker arm shaft, a rocker arm pedestal, a second rocker arm, a sleeve, a ring, and a follower arm, said adjacent member having a relief opening incorporated therein and said rocker arm having an internal hydraulic passage providing selective communication between the relief opening and the lash piston;
- providing hydraulic fluid to the lash piston during an engine braking mode of engine operation, thereby taking up lash between the lash piston and an engine valve;
- opening the engine valve responsive to movement of the rocker arm and the provision of hydraulic fluid to the lash piston, to carry out an engine braking event;
- and
- terminating the engine braking event responsive to relative motion between the rocker arm and the adjacent member to thereby selectively establish hydraulic communication between the internal hydraulic passage in the rocker arm and the relief opening in the adjacent member.
An engine braking system, for providing a compression release valve event in an internal combustion engine, comprising:
- a rocker arm having a central bore, a lash piston, a control valve, an accumulator piston;
- an internal hydraulic passage in the rocker arm extending between the lash piston, the control valve, and the accumulator piston;
- means for pivoting the rocker arm to provide an engine braking valve event;
- means for biasing the control valve into a closed position during an engine braking mode;
- and
- means for selectively opening the control valve during the engine braking mode.
Dependencies are inferred from the claim text.