When the engine throttle control knob is rotated, the output voltage changes according to the position of the knob, and this signal is input to the engine throttle controller. The engine throttle controller combines the voltage of the knob with the motor position installed in the engine throttle control motor.
After comparing the voltage of the monitoring potentiometer, drive the motor at the position specified by the knob. When the voltage of the knob is consistent with the voltage of the potentiometer, the throttle controller cuts off the current of the motor and stops it from rotating.
The engine control motor is equipped with a steel cable. The end of this steel cable is connected to the adjustment rod of the fuel injection pump of the engine. Therefore, as the motor rotates, the adjustment rod always moves to achieve the purpose of controlling the engine speed.
1. Engine control motor
Using a DC motor with a potentiometer for position monitoring inside. When the engine throttle control motor has an abnormal load (when the control cable is aged or bent), the engine throttle controller limits the current of the throttle control motor to protect the system. Therefore, even if the engine throttle control knob is rotated, the engine throttle control motor does not move. When the abnormal load is removed, turn off the start switch and restart, turn the control knob of the engine throttle, everything can return to normal. When replacing or adjusting the engine control motor, it must be carried out according to the adjustment method of the engine control device. If the adjustment is wrong, the performance of the equipment cannot be properly played.
2. Hitachi excavator engine throttle control knob
Engine throttle control knob is shown in Figure 1534. A potentiometer is installed inside the knob. When the knob is turned, the resistance value of the potentiometer changes, and the output voltage (between 2/3 terminals) supplied to the throttle controller also changes accordingly.
