500SEC (140.070) V8-5.0L (119.970) (1993)
/v8-5.0l_(119.970)/Page-1120001.png)
Electronic Throttle Actuator: Description and Operation
Accelerator Actuator
Accelerator Actuator
The accelerator actuator consists of a reversible DC motor with a multistage reduction gear. The output shaft for the throttle valve control linkage is
attached to the output lever. The moving contact (wiper) of the potentiometer as well as the double-contact safety switch are both attached to the output
shaft. If the ignition switch is in the on position or if the engine is running, the electronic accelerator control unit supplies a constant voltage to the
potentiometer. The moving contact (wiper) returns a voltage to the control unit which is directly proportional to the output shaft and therefore throttle
valve position. This position signal is processed by the system control portion of the control unit, which energizes the motor to change the position of the
throttle valve if necessary. The accelerator actuator output shaft can move through an angle of 88 - 92°, allowing a full range of throttle valve openings
from idle to wide open. The DC motor has a high adjustment speed, covering the entire adjustment angle in approx. 120 m sec. At the same time, the
positioning is very accurate.
Accelerator Actuator
The rotation of the actuator is different for different engines (see SYSTEM ID). On engines 116 and 117 the adjustment between idle and wide open
throttle turns clockwise. With engines 103, 104 and 119 it turns counterclockwise.
