Fuel supply system

A motor vehicle, comprising:

• an internal combustion engine;
• and
• a fuel supply system configured to supply fuel to the internal combustion engine, wherein the fuel supply system includes:
• a first tank corresponding to a main tank and a second tank corresponding to a buffer reservoir, wherein the first tank and the second tank are connected to one another via a fuel line:
• a first fuel pump and a first fuel filter arranged between the first tank and the second tank;
• a second fuel pump and a second fuel filter arranged between the second tank and the internal combustion engine;
• a water separator coupled to at least the first tank for separating water from the fuel;
• a first return line fluidly connected to the internal combustion engine on an inlet side and the second tank on an outlet side and the first fuel filter on a raw side;
• a preheating valve arranged in the first return line, wherein the preheating valve is configured to distribute the fuel flowing back from the internal combustion engine via the first return line to at least one of the first fuel filter and the second tank;
• and
• a second return line fluidly connecting the second tank to the first tank.

A method for operating a fuel supply system, comprising:

• a first tank corresponding to a main tank and a second tank corresponding to a buffer reservoir, wherein the first tank and the second tank are connected to one another via a fuel line;
• a first fuel pump and a first fuel filter arranged between the first tank and the second tank;
• a second fuel pump and a second fuel filter arranged between the second tank and an internal combustion engine;
• a water separator coupled to at least the first tank for separating contaminants from the fuel;
• a first return line fluidly connected to the internal combustion engine on an inlet side and the second tank on an outlet side and the first fuel filter on a raw side;
• a preheating valve arranged in the first return line, wherein the preheating valve is configured to distribute the fuel flowing back from the internal combustion engine via the first return line to at least one of the first fuel filter and the second tank;
• and
• a second return line fluidly connecting the second tank to the first tank;
• wherein the method includes the steps of:
• differentiating between at least four different operating modes, and wherein the at least four operating modes include an operating mode I, representing a normal operation, an operating mode II representing a risk of at least one of a thickening of the fuel and a clogging of at least one of the first fuel filter and the second fuel filter, an operating mode III representing a risk of the internal combustion engine overheating, and an operating mode IV, initiating an active drying of the fuel in the first tank.