Method of diagnosing malfunction of OBD controller system of hybrid electric vehicle
View Patent ↗A malfunction of an on-board diagnostic (OBD) controller system is diagnosed by comparing a voltage of an input part of an OBD controller with a voltage of a battery. The OBD controller is connected to the battery through a communication line in a hybrid electric vehicle (HEV). When an input voltage measuring circuit or the controller is malfunctioning, the malfunction is diagnosed.
1 . A method of diagnosing a malfunction of an on-board diagnostic (OBD) controller system of a hybrid electric vehicle (HEV), the method comprising:
providing a battery connected to an OBD controller through a communication line in the HEV;
outputting, by the OBD controller, an average value of a system voltage of an input part for a predetermined time; and
outputting an average value of a voltage of the battery for the predetermined time;
outputting, by the OBD controller, a malfunction signal of the OBD controller system when a difference between the average value of the system voltage of the input part and the average value of the voltage of the battery exceeds a predetermined reference value; and
outputting, by the OBD controller, a normal signal of the OBD controller system when the difference between the average value of the system voltage of the input part and the average value of the voltage of the battery is equal to or smaller than the predetermined reference value; and
wherein the predetermined reference value is set according to a state of charge (SOC) of the battery of the HEV;
further comprising receiving, by the OBD controller, the SOC of the battery before outputting the malfunction signal of the OBD controller;
wherein the predetermined reference value is set to 2 V when the SOC of the battery is 80% or more and 4 V when the SOC of the battery is 30% or less.
2 . The method of claim 1 , further comprising receiving, by the OBD controller, a vehicle speed of the HEV before calculating the average value of the system voltage of the input part,
outputting, by the OBD controller, the normal signal of the OBD controller system when the vehicle speed of the HEV is equal to or lower than 10 KPH.
3 . The method of claim 1 , further comprising receiving, by the OBD controller, an operating state of a starter for starting the HEV before the calculation of the average value of the system voltage of the input part,
outputting, by the OBD controller, the normal signal of the OBD controller system, when the starter is not operating.
4 . The method of claim 1 , further comprising receiving, by the OBD controller, a communication state of a controller area network (CAN),
outputting, by the OBD controller, the normal signal of the OBD controller system, when there is an abnormality in the CAN communication state.
5 . The method of claim 4 , wherein the OBD controller receives the voltage of the battery via CAN communication.