Method for operating a fuel system, and fuel system

A method of operating a fuel system of an internal combustion engine, comprising:

• fluidly connecting a ventilation device of the fuel system via a vent line with a fuel tank of the fuel system for ventilation of the fuel tank;
• providing an actuator for actuating a first vent valve of the ventilation device;
• connecting in parallel to the first vent valve two overflow valves configured to enable opposite throughflow directions and to open or close a throughflow in dependence on a pressure differential between a first section of the vent line on one side of the first vent line and a second section on an opposite side of the first vent valve;
• ascertaining a magnitude of deformation of a deformation of a deformation zone of the fuel tank as caused by an internal pressure of the fuel tank;
• and
• opening a second vent valve of the ventilation device when the magnitude of deformation exceeds a limit value.

A fuel system of an internal combustion engine, comprising:

• a fuel tank;
• a ventilation device for ventilating the fuel tank, said ventilation device including first and second vent valves, and a vent line in fluid communication with the fuel tank;
• an actuator configured to actuate the first vent valve;
• and
• two overflow valves connected in parallel to the first vent valve and configured to enable opposite throughflow directions and to open or close a throughflow in dependence on a pressure differential between a first section of the first vent line on one side of the vent line and a second section on an opposite side of the first vent valve;
• wherein a magnitude of deformation of a deformation of a deformation zone of the fuel tank as caused by an internal pressure of the fuel tank is ascertained and the second vent valve of the ventilation device is opened when the magnitude of deformation exceeds a limit value.