Patent ID: 8886448

Claim:
A method of providing a volume-mass law for determination of instant mass fuel flows which are fed by a dosing feeder from a fuel tank to an engine in a helicopter, the method of providing said volume-mass law for determination of fuel flow rates from the fuel tank to said engine, to allow calculation of remaining flight time, point of non-return and fuel quantity left in the fuel tank till landing, including: a step of metering: a permittivity ξ of fuel in the fuel tank, a temperature T R of fuel in said fuel tank, and a step of determining a sample type of fuel with a given density ρ 0 in said fuel tank by associating the measured permittivity ξ and temperature T R of the fuel in said fuel tank to at least one data pairξ, T of different types of known fuels, said method being characterized by the further steps: said method comprising the steps of: detecting temperatures Tm and measuring instant volume flow rates Q m at defined times t n , t n−1 . . . of the sample type of fuel at said dosing feeder, providing either fuel volumes V R and temperatures T R or fuel masses at defined times t n , t n−1 . . . in said fuel tank, calculating real-time parameters a, b of an equation ρ=aT+b from either fuel volumes and the temperature T R or fuel masses in said fuel tank, with the parameter ρ for real-time densities ρ n, ρ n−1 . . . at defined times t n , t n−1 . . . of a time interval Δt from t n till t n−1 , the parameter a being a gradient constant and the parameter b being the offset for said given sample fuel, and integrating said instant volume flow rates Q m during said time interval Δt at a value Tm of said temperature, calculated by the mean of said equation for real-time densities ρ n , ρ n−1 . . . at defined times t n , t n−1 . . . for providing the volume-mass law.