Abstract: A fuel-feed line extends from a diesel-fuel tank to a fuel pump for a diesel engine and the upstream side of this fuel pump is connected via a return line back to the tank. A feed flow meter is provided in the feed line for measuring flow therein and a return flow meter is provided in the return line. A common housing carries both of these flow meters so that the difference between the two measured flows, which constitutes the fuel consumed by the engine, can easily be calculated.