METHOD FOR DETERMINING THE INSTANTANEOUS MASS FLOW RATE OF A GAS, CORRESPONDING DEVICE AND COMPUTER PROGRAM

The invention relates to a method and device for determining the instantaneous mass flow of a gas, such as air in a conduit (12), like an air intake channel of an internal combustion engine of a motor vehicle. The method comprises the steps of: - measuring (81) a time-domain signal of gas pressure at a first measurement point (A) of said conduit (12); - measuring (82) a time-domain signal of gas pressure at a second measurement point (B) of said conduit (12). According to the invention, said method further comprises the steps of: - obtaining (83) for each of the measured time-domain signals of gas pressure the corresponding frequency spectrum ; - obtaining (84) the frequency spectrum of the mass flow at each of said measurement points (A, B) using a model in the frequency domain linking the frequency spectrum of the measured gas pressure at said measurement points (A, B) to the frequency spectrum of the mass flow at said measurement points (A, B) ; - obtaining (85) the time-domain signal of the mass flow rate at any measurement point (A, B) from the frequency spectrum of the mass flow at said corresponding measurement point (A, B).