Electrohydraulics Flashcards
Match electrical system components.
Vehicle charging system and storage battery.
Circuit overload protection
Relay
Control Switches
Solenoids
wiring harnesses and connectors
Vehicle charging system and battery: Provides a stable source of voltage and an adequate supply of current.
Circuit overload protection: Prevents overheating of electrical control system components.
Relay: Reduce control circuit current flow.]
Control switches: Provides a means for the operator to initiate system operation.
Solenoids: Creates the force required to operate hydraulic components.
Wiring harness and connectors: Used to connect system components and carry current flow.
The function of the bucket kickout on a wheel loader is to hold the bucket control lever in the rollback position until the bucket reaches the correct digging position.
True
Loader bucket kickout position and lift height can be adjusted by:
adjusting the position of the proximity switch in relation to the detector plate.
An example of a typical reference voltage sensor that sends a discreet voltage signal is a: A. Switch B. Joystick C. Potentiometer D. Solenoid
C. Potentiometer
In order to control a hydraulic system, the electronic control unit takes input signals from ______, compares them to ______________ and, when necessary, sends a ________ to output components.
sensors
parameters established in an internal program
voltage
The function of output components (actuators) of an electronic control system is to ________________.
Convert electrical output signals from the ecu into output action.
The force created by a proportional solenoid is proportional to: A. Hydraulic system pressure B. Pump flow rate. C. Output voltage signal from the ECU. D. Input current signal to the ECU.
C. Output voltage signal from the ECU.
Why do closed loop electronic contol systems offer more accurate control than open loop systems?
Closed loop electronic control systems include sensors that send a feed back signal to the ECU from the hydraulic actuator. By monitoring actuator motion, the ECU can provide more accurate control of its position, velocity or acceleration.
Name one way to prevent stiction.
By using dither to keep the spool moving or vibrating slightly, stiction is prevented.
The main disadvantage of electronically controlled hydraulic systems is that they are:
a. very expensive
b. not able to provide variable speed control
c. not very energy efficient.
d. operated on less than full system voltage.
B. Not able to provide variable speed control.
Proximity switches are commonly used in loader bucket kickout and lift height control systems. When the dectector plate is in close proximity to the switch, the switch is:
a. energized
b. grounded
c. open
d. closed
d. closed
The function of input devices in an electronically controlled hydraulic system is to:
a. be the brain of the control system
b. actuate hydraulic components.
c. send information in the form of electrical signals to the ECU.
d. provide system self diagnosis.
c. send information in the form of electrical signals to the ECU.
Lever operated potentiometers that are used as operator controls are called_________________.
Joysticks.
Self diagnosis is a feature that is often incorporated into the internal program of the ECU. The self diagnosis program generates a ___________ that indicates the location and nature of system malfunctions.
fault code
Solenoids used in electrical control systems often function in discrete positions.
True
