Malfunction location detection device for automatic transmission, and automatic transmission provided with same

An automatic transmission for a vehicle which is a stepwise automatic transmission that is mounted on a vehicle, which is arranged to attain a plurality of shift stages by selectively engaging a plurality of frictional engagement elements, and which is arranged to switch a shift stage by a changeover of one of a plurality of frictional engagement elements, and to switch the shift stage by changeovers of two or more pairs of the frictional engagement elements, the automatic transmission comprising:

• a malfunction part sensing device being configured, when a malfunction by a malfunction mode of an engagement failure or disengagement failure is generated in one of the plurality of the frictional engagement elements, to identify the one of the frictional engagement elements in which the malfunction is generated,
• the malfunction part sensing device including;
• a shift stage monitoring section configured to monitor the shift stages before and after the shift of the automatic transmission;
• a malfunction sensing section configured to sense the malfunction mode from a behavior of the vehicle which is generated in accordance with the malfunction;
• and
• a malfunction part limiting section configured to limit the one of the frictional engagement elements in which the malfunction is generated, based on the malfunction mode and a shift manner by a combination of the shift stages before and after the shift,
• wherein in the shift stage switching by the changeovers of the two or more pairs of the frictional engagement elements, the malfunction part limiting section is configured to grasp the frictional engagement elements which are controlled to be operated at the shift, from the shift manner, and to limit the one of the frictional engagement elements in which the malfunction is generated, from the grasped frictional engagement elements to a part of the frictional engagement elements, and
• wherein the malfunction part sensing device comprises at least one operation state sensor configured to sense an operation state of an engagement or a disengagement of at least one predetermined frictional engagement element in the plurality of the frictional engagement elements, but less than all of the frictional engagement elements of the plurality of the frictional engagement elements;
• and when the predetermined frictional engagement element relates to the shift, the malfunction part limiting section is configured to limit the one of the frictional engagement elements in which the malfunction is generated, to a part of the frictional engagement elements, based on the shift manner of the shift, the malfunction mode, and the operation state of the predetermined frictional engagement element,
• a shift control section configured, when the malfunction part sensing device identifies the one of the frictional engagement elements in which the malfunction is generated, to determine a malfunction corresponding shift stage, and to switch the shift stage to the malfunction corresponding shift stage, and
• wherein when the operation state sensor identifies the one of the frictional engagement elements in which the malfunction is generated, a malfunction corresponding shift stage is determined based on the identified one of the frictional engagement elements in which the malfunction is generated, and the shift stage is shifted to the malfunction corresponding shift stage, and
• when the operation state sensor does not identify the one of the frictional engagement elements in which the malfunction is generated, the one of the frictional engagement elements in which the malfunction is generated is identified by repeatedly performing a prove control in which a selectable shift stage is selected in a stop state of the vehicle, in which the frictional engagement elements are engaged or disengaged to attain the shift stage, and in which a traveling of the vehicle is attempted, the malfunction corresponding shift stage is determined based on the identified one of the frictional engagement elements, and the shift stage is shifted to the malfunction corresponding shift stage.