FIELD: machine building.
SUBSTANCE: invention relates to determination of fuel vapour pressure in fuel system of an internal combustion engine. Disclosed are methods and system for determining fuel vapour pressure. According to one example, the method for a vehicle comprises: during engine start-up, after the latter has been off for at least a minimum period of time, active control of fuel pressure in fuel system in order to ensure ratio of volumes of "vapour-liquid" is greater than zero and then recording of measured pressure and temperature of fuel in fuel system. Thus, it is possible to accurately measure pressure of fuel vapours at given temperature under isothermal conditions and thus improve quality of volatility estimation of fuel.
EFFECT: technical result is improvement of fuel volatility estimation accuracy.
20 cl, 6 dwg
