| 摘要 |
<P>PROBLEM TO BE SOLVED: To control a shift position of automatic transmission at the time of abnormality in which supply voltage becomes overvoltage, by adding a simple fail-safe circuit in a power circuit of control circuit of the automatic transmission. <P>SOLUTION: The controller performs a gear change control of an automatic transmission 5 installed on a vehicle by switching a plurality of hydraulic circuits 4. A microcomputer 1 determines an optimized shift position of the automatic transmission depending on vehicle operating condition. IPD2A-2C turn ON/OFF supply hydraulic pressure from the hydraulic circuit 4 to the automatic transmission depending on an output of the microcomputer 1. When a power voltage +B becomes overvoltage, IPD2A-2C turn OFF the supply hydraulic pressure from the hydraulic circuit 4 to the automatic transmission 5 irrespective of output condition from the microcomputer 1 to the IPD2A-2C, so as to set the shift position of the automatic transmission to a third speed, i.e., a safe running position of the vehicle. <P>COPYRIGHT: (C)2009,JPO&INPIT |
