Electric vehicle diagnostic apparatus

An electric vehicle diagnostic apparatus to be installed in an electric vehicle, the electric vehicle comprising temperature sensors disposed at different positions of either a drive motor or an inverter configured to drive the drive motor, the temperature sensors being configured to detect respective temperatures at the different positions, the electric vehicle diagnostic apparatus comprising:

• a controller configured to, during a startup period of the electric vehicle:
• calculate a discrepancy between detected values of the temperature sensors;
• determine whether the discrepancy is greater than or equal to a discrepancy threshold;
• set a duration of a mask process to a first length of time in response to determining that the discrepancy is greater than or equal to the discrepancy threshold;
• set the duration of the mask process to a second length of time shorter than the first length of time in response to determining that the discrepancy is less than the discrepancy threshold;
• execute the mask process during which the controller refrains from executing a predetermined diagnosis of the temperature sensors;
• and
• resume the predetermined diagnosis of the temperature sensors upon expiration of the duration of the mask process,
• wherein the predetermined diagnosis includes at least one of a shift abnormality diagnosis and a linearity abnormality diagnosis,
• wherein the shift abnormality diagnosis is a diagnosis that determines that a shift abnormality is present, based on a condition that an output difference between or among the temperature sensors is greater than or equal to a predetermined threshold and continues for at least a predetermined duration,
• wherein the linearity abnormality diagnosis is a diagnosis that determines that a linearity abnormality is present, based on (i) a difference between rates of change in outputs from the temperature sensors being greater than or equal to a predetermined threshold, (ii) the difference continuing for at least a predetermined duration, and (iii) the outputs changing under a predetermined change condition,
• wherein determining that the discrepancy is greater than or equal to the discrepancy threshold is indicative of motor lock immediately before system startup, and wherein the mask process is executed to refrain from executing the shift abnormality diagnosis and the linearity abnormality diagnosis when determining that the discrepancy is greater than or equal to the discrepancy threshold,
• wherein, after release of motor lock of the drive motor, the controller is configured to set the duration of the mask process to a third length of time that is longer than the first length of time and the second length of time, and
• wherein the drive motor includes a plurality of coils corresponding to different current phases, and the temperature sensors are disposed to detect temperatures of respective coils corresponding to the different current phases at different positions adjacent to respective ones of the plurality of coils, or wherein the inverter includes a plurality of switching elements corresponding to different current phases, and the temperature sensors are disposed to detect temperatures of respective switching elements corresponding to the different current phases at different positions adjacent to respective ones of the plurality of switching elements.