Piston-type internal-combustion engine having activatable, mechanically actuated cylinder valves

#In a piston-type internal combustion engine having mechanically actuated cylinder valves that are actuated with the aid of at least one camshaft via roller drag levers, it is possible to deactivate the cylinder valves of a portion of the cylinders in order to operate the engine in partial-load operation, for example, operations which only some of the cylinders are fired, whereas the cylinders having deactivated cylinder valves are not fired, but are idle. The cylinder valves can be deactivated cyclically, so other cylinders can always be fired, taking into consideration running smoothness. The active cylinders can then be fired under full-load conditions, and thus under optimum operating conditions, with the piston-type internal-combustion engine only delivering a partial load overall.

#The arrangements known to this point for deactivating the cylinder valves have a very complicated design, and require a considerable amount of space.

#It is the object of the invention to provide a piston-type internal-combustion engine having deactivatable cylinder valves and a simple valve-gear design.

#The invention is explained in detail using schematic drawings of an exemplary embodiment.

#FIG. 1 is a side view of a cylinder valve that can be actuated by via a cam and roller drag levers according to the invention, in the activated state.

#FIG. 2 shows the cylinder valve according to FIG. 1, in the deactivated state.

#FIG. 1 illustrates a mechanical cam-valve gear for actuating a cylinder valve 1. The stem 2 of the cylinder valve 1 is provided with a spring plate 3 that is supported on a valve spring 4 that holds the valve 1 in its closed position as shown.

#A roller drag lever 5, which is essentially formed by a partial lever 5.1 and a partial lever 5.2, is provided for actuating the cylinder valve 1. The two partial levers 5.1 and 5.2 are hinged to one another via an articulated shaft 6, on which a roller 7, which rests on the cam 8 of the associated camshaft, is seated to rotate freely.

#The roller drag lever 5 is supported at its free end 5.11 associated with the partial lever 5.1 on the end of the valve stem 2. The free end 5.21 of the drag lever 5 associated with the partial lever 5.2 supports the roller drag lever 5, via a spherical cap 5.23, on the moving part 9 of a hydraulic play-compensation element 10 of a known design. The play-compensation element 10 is permanently connected to the engine block 11, and is connected to a compressed-oil supply via a corresponding conduit arrangement 12 in the engine block.