| 摘要 |
An off-highway heavy duty dump truck includes an engine, a torque converter, a shiftable multi-speed hydraulically operated power transmission for driving the truck wheels, and a control system for the transmission. The transmission includes internal clutches which are selectively operated by a solenoid-operated rotary speed range selector valve to effect shifting in neutral, reverse or several forward speed ranges. The control system includes a manually operable multi-position speed range selector switch, sensing devices for ascertaining transmission input and output speeds, a limit switch and rotary switch responsive to the condition and rotary position, respectively, of the rotary range selector valve, and other condition responsive switches. The control system further includes an electronic controller having logic circuits therein for receiving input signal information from the aforesaid switches and sensing devices and for providing output signals to operate the rotary range selector valve and effect automatic shifting of the transmission to a selected speed range, provided predetermined conditions are met. The electronic controller provides operational safeguards until such conditions are met, responds appropriately to system failures, and displays of relevant system information. |
