Hydraulic drive for accelerating and braking components

A hydraulic drive for accelerating and braking dynamically moving components of an internal combustion engine, the hydraulic drive comprising:

• a single-acting working cylinder defining a driving chamber;
• a drive piston configured to slide within the single-acting working cylinder so as to engage at least one gas exchange valve, the drive piston including an opening pressure acting surface in the driving chamber;
• at least one restoring energy accumulator configured to impart a biasing force on the at least one gas exchange valve;
• at least one drive pressure reservoir configured to provide a drive pressure of a hydraulic pressure medium at a first pressure,
• at least one base pressure reservoir configured to store the hydraulic pressure medium at a base pressure which is less than the first pressure;
• at least one inflow control valve configured to selectively connect the at least one drive pressure reservoir to the driving chamber so as to open the at least one gas exchange valve;
• and
• at least one drain control valve configured to selectively connect the driving chamber to the at least one base pressure reservoir,
• wherein the drive piston further includes at least one control edge corresponding to an inflow opening of the single-acting working cylinder such that, when a cutting stroke of the drive piston is reached, the at least one control edge prevents an inflow of the drive pressure into the driving chamber,
• wherein a remaining hydraulic drive force of the hydraulic pressure medium drops to zero or reverses direction when the cutting stroke is reached,
• wherein the at least one drain control valve is configured as a 2/2-way valve with two additional intermediate positions which are traversed in a time-controlled manner when switching to an open discharge position, the two additional intermediate positions including a first intermediate position and a second intermediate position,
• wherein the first intermediate position is an open position which initiates a closing movement of the at least one gas exchange valve, and
• wherein the second intermediate position is a closed position which leads to a pressure build-up in the single-acting working cylinder for a set period of time which pushes the hydraulic pressure medium back into the at least one drive pressure reservoir.

A hydraulic drive for accelerating and braking dynamically moving components of an internal combustion engine, the hydraulic drive comprising:

• a double-acting working cylinder defining a driving chamber and a braking chamber;
• a drive piston configured to slide within the double-acting working cylinder so as to engage at least one gas exchange valve, the drive piston including an opening pressure acting surface in the driving chamber, and a closing pressure acting surface in the braking chamber;
• at least one restoring energy accumulator configured to impart a biasing force on the at least one gas exchange valve;
• at least one drive pressure reservoir configured to provide a drive pressure of a hydraulic pressure medium at a first pressure;
• at least one base pressure reservoir configured to store the hydraulic pressure medium at a base pressure which is less than the first pressure;
• at least one inflow control valve configured to selectively connect the at least one drive pressure reservoir to the driving chamber so as to open the at least one gas exchange valve;
• and
• at least one drain control valve configured to selectively connect the driving chamber to the at least one base pressure reservoir,
• wherein the drive piston further includes at least one control edge corresponding to an inflow opening of the double-acting working cylinder such that, when a cutting stroke of the drive piston is reached, the at least one control edge (i) prevents an inflow of the drive pressure into the driving chamber, and/or (ii) prevents a low-loss outflow of the hydraulic pressure medium from the braking chamber to the at least one base pressure reservoir,
• wherein a remaining hydraulic drive force of the hydraulic pressure medium drops to zero or reverses direction when the cutting stroke is reached, and
• wherein the at least one drain control valve is configured as a 2/2-way valve with two additional intermediate positions which are traversed in a time-controlled manner when switching to an open discharge position, the two additional intermediate positions including a first intermediate position and a second intermediate position,
• wherein the first intermediate position is an open position which initiates a closing movement of the at least one gas exchange valve, and
• wherein the second intermediate position is a closed position which leads to a pressure build-up in the double-acting working cylinder for a set period of time which pushes the hydraulic pressure medium back into the at least one drive pressure reservoir.