| 摘要 |
<p><P>PROBLEM TO BE SOLVED: To provide a method for setting a highly accurate and robust standby hydraulic pressure value. <P>SOLUTION: An electronic control part of an automatic transmission makes stepped hydraulic pressure waveform control wherein a step pressureΔP is very small while a step intervalΔt is sufficiently long. Changes in flow rate are negligible and piston speed is slow and constant so that pressure equivalent to the pressure of a return spring is available. In a learning mode, the electronic control part of the automatic transmission makes the driving control of hydraulic pressure, monitors a difference value Nte between turbine speed Nt and engine speed Ne in a measuring cycle sufficiently shorter than the time intervalΔt, detects whether the stroke of a piston has been out of the area of flow rate control (piston end), and sets an engagement hydraulic pressure Pc at that time as a standby hydraulic pressure value related to a frictional engagement element. <P>COPYRIGHT: (C)2008,JPO&INPIT</p> |
