Control of automatic transmission

摘要

A procedure for open and closed loop control of an automatic gearbox has the following steps. First, it is established whether the input shaft speed sensor (19) is in normal or failure mode, followed by the same for the output shaft speed sensor (20). Then the measured output shaft speed is multiplied by the transmission ratio and compared with the measured input shaft speed. If they agree within a certain tolerance, this "confirms the previous assumptions that the sensors are OK" (I presume) (The essence of the patent is then repeated several times up to para 7.) The gearbox control is changed from normal mode to failsafe mode using a given transmission ratio if a sensor error is detected, followed by testing for resumption of normal mode.