| 摘要 |
PURPOSE: A method for deciding the fuel vapor pressure of a vehicle by a board unit is provided to decide the fuel vapor pressure of a vehicle tank or vehicle tank system of the vehicle including a tank ventilation system just by the board unit during traveling. CONSTITUTION: In a method for deciding the fuel vapor pressure of a fuel tank system of a vehicle including a tank ventilation system by a board unit, the fuel vapor pressure is decided through temperature relation of at least one variable of the tank ventilation system indirectly related to the inner pressure existing in the fuel tank system. Fuel temperature and external or atmospheric pressure is considered in deciding the fuel vapor pressure. The method for deciding the fuel vapor pressure of the fuel tank system of the vehicle comprises steps of making the current value of fuel vapor pressure identical with the average fuel vapor pressure decided previously after starting a recognition routine(500,510); temporarily measuring the current value of a value from the tank ventilation system(520); detecting a change of the value(530); calculating a corresponding change of a previously recognized value(p-vapor-fuel) directly after increase of the value is controlled(540); temporarily storing the value(p-vapor-fuel) to freely use the recognized vapor pressure value in new starting of an engine of the vehicle or restarting of the vehicle(550,580); and detecting the filling of fuel(560). The previously recognized vapor pressure value is rejected and new recognition is started when the filling of the fuel is detected.
|
