Hydraulically controllable globe valve

#The present invention relates to a hydraulically controllable globe valve, in particular a gas exchange valve of an internal combustion engine, having a stem piston to which a pressure can be applied by hydraulic spring means connected to a pressure source, and which can move from one end position in the direction of a second end position.

#A hydraulic actuator for a globe valve in an internal combustion engine, which is known from German Patent No. 38 36 725, has a piston connected to the valve shaft and guided in a cylindrical working space, with a spring-loaded arrangement provided at both ends of the piston so that the piston is forced, when rest, into a central position in which the globe valve is partially open. To move the globe valve into an open or closed position, hydraulic pressure can be alternately applied to the piston from a pressure source. A feed pump serving as the pressure source and a switchable multiway valve are provided for this purpose.

#A hydraulic valve controller for a globe valve in an internal combustion engine, which is known from German Patent No. 195 01 495, has a helical compression spring that loads the globe valve in the closing direction as well as hydraulic spring means that can be connected alternately to a pressure source and a pressure sink by a switchable multi-way valve, with these spring means being able to move the globe valve in the opening direction via a stem piston that can move along with the globe valve.

#FIG. 1 shows a schematic longitudinal sectional view of a first embodiment of a hydraulically controllable globe valve in an internal combustion engine having a stem piston to which a pressure can be applied as well as pressure control means that can be connected to a pressure source via a control groove in the stem piston.

#FIG. 2 shows a view according to FIG. 1, but for a second embodiment of the hydraulically controllable globe valve having pressure control means that are completely integrated into the stem piston.

#FIG. 3 shows a view according to FIG. 1, but for a third embodiment of the hydraulically controllable globe valve having pressure control means designed as a shutoff element for a closable pressure channel.

#An internal combustion engine, in particular a reciprocating engine for a motor vehicle, has multiple working cylinders in the known manner whose combustion chambers are each provided with at least one globe valve 1 for supplying combustion air (intake valve) and for discharging the combustion exhaust gases (exhaust valve). A hydraulic control mechanism 30, 40, 50, 60, which can be designed in different embodiments according to FIGS. 1 through 4, is provided to control each globe valve 1. Hydraulic control mechanisms 30, 40, 50, 60 of globe valves 1 of all working cylinders in the internal combustion engine preferably can be controlled by engine electronics designed in the form of a central control unit. Each of FIGS. 1 through 4 shows the valve in its closed position.

#According to all embodiments of the hydraulic control mechanism, globe valve 1 has a valve stem 2 and a spring holder 3 permanently connected to the latter. A spring force operating in the valve closing direction can be applied to valve stem 2 by a helical compression spring 4 via spring holder 3.

#Valve stem 2 is positioned in corresponding hydraulic control mechanism 30, 40, 50, 60 so that it can move linearly together with a stem piston 5, with stem piston 5 guided in a cylindrical guide 6a of a valve housing 6. At one point, cylindrical guide 6a widens to form a working space 7, through which stem piston 5 passes. Working space 7 contains a control piston 8, which forms one piece with stem piston 5. Control piston 8 includes an upper and a lower plunger 8a and 8b, which enter corresponding pressure chambers 7a and 7b of working space 7. Pressure chambers 7a and 7b are designed so that they are separated from the remaining volume of working space 7 by plungers 8a and 8b at the end positions of stem piston 5.