Device in a cylinder head for an internal combustion engine

Device in a cylinder head for an internal combustion engine, said cylinder head (1) for each cylinder (3) comprising at least one inlet channel (9) with an inlet valve (8) for controlling the communication between the inlet channel and a combustion chamber (5), which is at least partially located in the cylinder head (1), and at least one outlet channel (9) with an outlet valve (8) for controlling the communication between the outlet channel and the combustion chamber, each of the valves being a poppet valve (8) and being shiftable between a first position in which the valve disc (10) is in contact with a valve seat (15) in the cylinder head (1) to shut off the communication between the combustion chamber (5) and the channel (9) in question, and a second position in which the valve disc (10) is spaced from the valve seat (15) and opens the communication, characterized in that at least one of the valves (8) for each cylinder (3) is movable to a third position, in which the valve disc (10) is in contact with a second valve seat (19) disposed in the cylinder head, that the first and the second valve seats (15,19) are spaced from each other in the channel (9) in question, and that the channel (9) is widened to a chamber (13) between the two valve seats (15,19).