Steuerungssystem für automatisches Fahrzeuggetriebe

摘要

A control method/system (200) for a control system (104) for semi-automatically executing automatically selected upshifts and downshifts of a mechanical transmission system (10) is provided. The control system includes a central processing unit (106) for receiving input signals indicative of transmission input shaft (16) and output shaft (90) speeds (IS, OS) and processing the same in accordance with predetermined logic rule to issue command output signals to a transmission actuator (112, 70, 96) to implement the selected shifts by automatic shifting into neutral upon a naturally or manually caused torque reversal of the transmission and remaining in neutral until the vehicle operator causes substantially synchronous conditions to occur. The method/system (200) includes calculating a first and second reference value (REF-UP, REF-DN) as functions of input shaft speed and only preselecting upshifts of output shaft acceleration (dOS/dt) exceeds the first reference (REF-UP) and only preselecting downshifts if output shaft acceleration (dOS/dt) is less than the second reference value (REF-DN). The first and second reference values vary with the value of input shaft speed over ranges (150-154, 152-160) thereof.