301i: Electrohydraulics Flashcards
The main disadvantage of electrically controlled hydraulic systems is that they are:
a) very expensive
b) not able to provide variable speed control
c) not very energy efficient
d) operate on less than full system voltage
b) Not able to provide variable speed control
301i Pg. 3
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. (T/F)
True
301i Pg. 7
Proximity switches are commonly used in loader bucket kickout and lift height control systems. When the detector plate is in close proximity to the switch, the
switch is:
Closed
301i Pg. 7
Loader bucket kickout position and lift height can be adjusted by:
Adjusting the position of the proximity switch in relation to the detector plate.
301i Pg. 9
The function of input devices in an electronic 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
301i Pg. 11
An example of a typical reference voltage sensor that sends a discreet voltage signal is a:
a) Switch
b) Joystick
c) Potentiometer
d) Solenoid
a) Switch
Discreet signal = On or Off
301i Pg. 12
Lever operated potentiometers that are used as operator controls are called:
Joysticks
301i Pg. 13, 33
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
Voltage
301i Pg. 14
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
301i Pg. 15
The function of output components (actuators) of an electronic control system is to:
Convert electrical output signals from the ECU into output action
301i Pg. 16
Solenoids used in electrical control systems often function in discrete positions. (T/F)
True
301i Pg. 3
The force created by a proportional solenoid is proportional to:
a) hydraulic system pressure
b) pump flow rate
c) output voltage from the ECU
d) Input current signal to the ECU
C) Output voltage signal from the ECU
301i Pg. 18
A pulse width modulated signal is used to actuate proportional solenoids because it:
a) Provides the most accurate solenoid action
b) Generates less heat than a DC signal
c) Provides an oscillating solenoid action
d) Is compatible with the signal from the joystick
c) Generates less heat than a DC signal
301i Pg. 18
Why do closed loop electronic control systems offer more accurate control than open loop systems?
Include sensors that send a feedback signal to the ECU from the hydraulic actuator
301i Pg. 20
How does pulse width modulation prevent the build-up of heat in solenoids?
The total applied voltage to the solenoid is less, resulting in less current flow through the coil and less heat.
301i Pg. 18
