Fuel consumption-measuring system and method for measuring the fuel consumption of an internal combustion engine

A fuel consumption-measuring system comprising:

• a fuel feed line;
• a first fuel pump configured to pump fuel from a fuel tank via the fuel feed line to a consumer;
• a fuel consumption-measuring device arranged in the fuel feed line;
• a first fuel return line arranged to branch off at the consumer and to open into the fuel feed line at an opening between the fuel consumption-measuring device and the consumer;
• a second fuel return line arranged to branch off from the fuel feed line between the first fuel pump and the fuel consumption-measuring device and to open into the fuel tank;
• a branch arranged to lead from the fuel feed line into the second fuel return line;
• a heat exchanger configured so that fuel from the second fuel return line extracts heat from the fuel of the first fuel return line;
• and
• at least one equal volume flow device arranged in the first fuel return line and in the second fuel return line, the at least one equal volume flow device being configured to provide an equal volume flow at the opening of the first fuel return line into the fuel feed line and at the branch leading from the fuel feed line into the second fuel return line;
• and
• a volume flow regulating unit;
• wherein,
• a first flow meter is arranged in the first fuel return line as the at least one equal volume flow device to provide the equal volume flow from the first fuel return line into the fuel feed line,
• a second flow meter is arranged in the second fuel return line as the at least one equal volume flow device to provide the equal volume flow from the fuel feed line into the second fuel return line, and
• both the first flow meter and the second flow meter are electrically connected to the volume flow regulating unit.