Patent ID: 7957919

Claim:
A diagnostic method for the determination of a true fuel flow rate supplied to a tested vehicle engine under various operating conditions, in particular an industrial vehicle, the method including: determination of a load applied to the tested vehicle engine by deceleration (Δn/Δt) of the tested vehicle engine from a first to a second preset rotation speed, in an absence of fuel supply; determination of the true fuel flow rate as reference fuel flow rate, corresponding to a flow rate measured on a reference engine of a same type as the tested vehicle engine as a function of the load the tested vehicle engine is subjected to wherein the true flow rate value is utilized to determine possible faults; detection of a series of parameters comprising: intake air flow rate (Air hfm ) by a specific sensor ( 8 ); supercharging pressure (p boost ) and supercharging temperature (T boost ) by appropriate sensors ( 19 , 10 ); percentage of oxygen (λ) present in the exhaust gases is sensed by an appropriate sensor, including a lambda sensor ( 9 ); flow rate of fuel (Q f ) supplied to the engine per time unit; determination of three mathematically independent magnitudes of air flow rates each based on at least part of said parameters; and comparison of said three magnitudes, for the determination of possible operation faults, characterized in that said fuel flow rate (Q f ) is said true flow rate.