METHOD OF AUTOMATICALLY CHANGING SPEED OF DUMP TRUCK FOR USE AS CONSTRCUTION VEHICLE

摘要

The engine controller (50) receives (53) a signal from an accelerator pedal (57) and controls fuel injection of an engine (10) by changing a rack (43) position. The controller (50) also calculates (54) the engine output condition as well as torque, based on signals from an engine rotation speed sensor (47) and a rack position sensor (46). A speed controller (60) has a first control circuit (61), which receives a shift position signal (R,N,D,V,IV,III,II) from a shift lever (63) and a vehicle speed signal from an input or output shaft sensor (48,49) of a gear box (16) and changes gears when the vehicle speed reaches predetermined values. A second control circuit (62) receives engine output condition and torque signals from the engine controller (50) and judges if gear change is possible, based on the current engine output power and the calculated value after gear change.