Empa Eidgenossische Materialprufungs-und Forschungsanstalt

Wolfgang Schneider Ingenieurburo

Patrik Soltic

Wolfgang Schneider

Andyn Omanovic

Christian Bach

Bernhard Rust

Bernhard Rüst

In order to provide a more reliable configuration for a hydraulic drive for accelerating and braking in particular a gas exchange valve () of internal combustion engines or other reciprocating engines, in particular if the occurring maximum travel of the moving mass can deviate considerably from an expected setpoint position, it is proposed that the drive piston () has at least one control edge () corresponding to an inflow opening (), which, when a defined travel hhas been attained, prevents the inflow of drive pressure pinto the drive chamber () and/or prevents the low-loss outflow of pressure medium from the brake chamber () to the basic pressure level (), wherein the remaining hydraulic drive force vanishes, becomes small or changes its sign when said travel his attained.

Hydraulic drive for accelerating and braking components

In order to ensure a simple, reliable and recuperative operation in a hydraulic drive () for accelerating and braking a gas exchange valve () of internal combustion engines or other reciprocating engines, it is proposed that a first pressure reservoir () for providing a first pressure pcomprises a restoring energy accumulator, preferably configured as a spring (), and at least one hydraulic base pressure reservoir (), which has a lower pressure pthan the first pressure reservoir (). In a connecting line () between the first hydraulic pressure reservoir () and the working cylinder (), a controllable opening () of a first valve () comprising at least one check valve () is arranged upstream or downstream in the flow path, which allows the pressure medium () to flow in the direction of working cylinder (), but prevents a backflow towards the pressure reservoir (). In order to also initiate the closing movement or to enable the breaking of the gas exchange valve in a hydraulically simple and reliable manner, in a second connecting line () between the first pressure reservoir () and the working cylinder () there is arranged a controllable opening () of a second valve () comprising a check valve (), which prevents a flow in the direction of the working cylinder (), but allows a return flow in the direction of the pressure reservoir ().

Hydraulic drive for accelerating and braking dynamically moving components

According to the invention, recuperation may be optimized for a hydraulically-operated gas exchange valve by provision of two fluid-filled pressure chambers and a movable regulating piston with two active faces each defining one of the pressure chambers. The pressure chambers are each connected to two hydraulic valves of which the first hydraulic valves may be pressurized from a first pressure reservoir and the second hydraulic valves may be connected to a base pressure reservoir. The first hydraulic valves may furthermore be connected to a second pressure reservoir. A control or regulation device switches the valves, from a rest position in a first accelerating phase and a braking phase. The second pressure reservoir is provided as pressure buffer for providing the pressure in the first pressure reservoir and/or for providing pressure for the fuel pump and/or for the fuel supply to an internal combustion engine and/or for providing pressure for a further gas exchange valve in the same or another combustion cylinder of the internal combustion engine.

Growing community of inventors

Uhwiesen, Switzerland

Patrik Soltic