A power-generating machine comprising: a working system having a first piston-cylinder system comprising a working piston and a working cylinder, the working piston dividing the working cylinder into a first working cylinder portion and a second working cylinder portion, a valve system having a first valve port and a valve element, the valve system and the working system being connected in a gas-conducting manner, the first valve port being connectable to a negative pressure source and the valve element being movably arranged in the valve system such that the valve element connects the first valve port to the first working cylinder portion in a first valve position and the first valve port to the second working cylinder portion in a second valve position in a gas-conducting manner, a control system, the control system comprising a second piston-cylinder system having a control piston and a control cylinder, the control piston being connected to the valve element such that a cyclical movement of the control piston in the control cylinder moves the valve element between the first valve position and the second valve position, the first valve port being connected to a valve switch via a first valve system supply line, the valve switch reversibly closing the first valve system supply line in a gas-conducting manner in a first valve switch position and reversibly opening the first valve system supply line in a gas-conducting manner in a second valve switch position, characterized in that a second valve system supply line and a third valve system supply line are arranged between the valve system and the valve switch, the valve switch connecting the valve system to the negative pressure source in a gas-conducting manner via the second valve system supply line in the first valve switch position and connecting the valve system to the ambient atmosphere of the power-generating machine in a gas-conducting manner via the third valve system supply line in the second valve switch position. a working system having a first piston-cylinder system comprising a working piston and a working cylinder, the working piston dividing the working cylinder into a first working cylinder portion and a second working cylinder portion, a valve system having a first valve port and a valve element, the valve system and the working system being connected in a gas-conducting manner, the first valve port being connectable to a negative pressure source and the valve element being movably arranged in the valve system such that the valve element connects the first valve port to the first working cylinder portion in a first valve position and the first valve port to the second working cylinder portion in a second valve position in a gas-conducting manner, a control system, the control system comprising a second piston-cylinder system having a control piston and a control cylinder, the control piston being connected to the valve element such that a cyclical movement of the control piston in the control cylinder moves the valve element between the first valve position and the second valve position, the first valve port being connected to a valve switch via a first valve system supply line, the valve switch reversibly closing the first valve system supply line in a gas-conducting manner in a first valve switch position and reversibly opening the first valve system supply line in a gas-conducting manner in a second valve switch position, characterized in that a second valve system supply line and a third valve system supply line are arranged between the valve system and the valve switch, the valve switch connecting the valve system to the negative pressure source in a gas-conducting manner via the second valve system supply line in the first valve switch position and connecting the valve system to the ambient atmosphere of the power-generating machine in a gas-conducting manner via the third valve system supply line in the second valve switch position.