Forward/backward shift control method for electronically controlled automatic transmission

Abstract

Abstract PURPOSE:To prevent generation of shift shock by reducing the forward or backward shift line pressure within a certain period of shift progress time in case the oil temp. of a transmission exceeds a certain level at the time of forward or backward shifting. CONSTITUTION:An electronic control device 10 operates shifting solenoids 4, 5 when either forward or backward shifting is judged with appropriate signal given by a shift position switch 3, and a friction engaging element is engaged selectively,and thus forward or backward shifting is made. If at this time the oil temp. of transmission exceeds a set level, the forward or backward shift line pressure is set some lower within a specified period of passing time after shifting clocked by a calculational timer circuit 24, and a primary valve 31 is controlled through a linear solenoid valve 34 so as to reduce the line pressure of hydraulic circuit temporarily. When progress of shifting has attained a certain time, the line pressure is returned to its normal value. Thus shocks at shifting can be reduced.

Inventors

• 👤 Yasunobu Ito
• 👤 康伸 伊藤
• 👤 Kenji Suzuki
• 👤 研司 鈴木
• 👤 Yasuo Mizuno
• 👤 水野　康夫

Bibliographic Details