| 摘要 |
PURPOSE: An error diagnostic method of a pressure sensor in a fuel tank for a vehicle is provided to improve precision and reliability of an error diagnostic by modeling threshold value to determine the error of the pressure sensor with main factors influencing the inner pressures of the fuel tank of the vehicle. CONSTITUTION: Whether a fixed diagnosis entry condition is satisfied or not is determined(S10). Necessary parameter value is received in order to model a fuel tank pressure upper limit and a fuel tank pressure lower limit(S20). The fuel tank pressure upper limit and the fuel tank pressure lower limit are modeled(S30,S40). A pressure value detected by a pressure sensor in a fuel tank is compared with the fuel tank pressure lower limit and the fuel tank pressure upper limit(S50,S60). The detected pressure value is determined as a normal state when the detected pressure is larger than the lower limit(S70), and the detected value is determined as an error when the detected pressure is smaller than the lower limit. [Reference numerals] (1) Sensor failure not detected; (2) Failure of a boil-off gas system related actuator not detected; (3) Fuel temperature within a predetermined range; (4) Fueling not detected; (AA) Start; (BB) Diagnosis entry condition; (CC) End; (S10) Diagnosis entry condition satisfied?; (S100) Actuator is determined as being normal after a leakage diagnosis of a boil-off gas system?; (S110) Determine a failure; (S20) Receive variables for modeling(Fuel temperature, Fuel amount, Fuel composition, Purge control flux, Canister loading capacity); (S30) Model the upper limit of fuel tank pressure, P_(max,n)= P_(max,n-1)+ΔP; (S40) Model the lower limit of fuel tank pressure, P_(min,n)= P_(min,n-1)+ΔP; (S70) Determine as being normal; (S80) Accumulate time values; (S90) Accumulated time value >= Set value ?
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