Perkins 1204F-E44TA Systems Operation Testing And Adjusting page 33

UENR4490-01
The coolant supplied by the engine will flow through
the tubes when the coolant diverter valve opens.
Coolant runs along the pickup tube to the bottom of
the tank and then spirals around the level sensor.
The heat from the coolant will thaw any frozen DEF in
the tank or header. The heat will also prevent the
DEF from freezing around the pickup tube.
DEF Pickup Tube
The DEF is pulled from the bottom of the tank
through a screen.
DEF Tank Header Filter
At the end of the DEF Pickup tube is a 100 micron
filter to filter debris from entering the system.
DEF Return
The DEF is returned back to the tank from the DEF
injector.
DEF Tank Temperature Sensor
At the bottom of the tank header near the DEF tank
header filter is a tank temperature sensor. The
temperature sensor is a passive thermistor. The
resistance of the thermistor varies with temperature.
This sensor monitors the temperature of the DEF in
the tank. This temperature is used to determine when
to turn on the coolant diverter valve.
DEF Quality Sensor
At the bottom of the tank header next to the DEF tank
header filter is the DEF quality sensor. The ultrasonic
DEF quality sensor uses the speed of sound within a
fluid to identify concentration of the fluid. This is
achieved by measuring the time it takes for the
emitted ultrasonic signal to be reflected off a known
fixed reference point. Based on the chemical
properties and temperature of the fluid, the sensor is
able to detect urea concentration with an accuracy of
up to 2 percent. If the sensor detects the quality of
DEF is not within specifications, a fault code will trip
indicating the DEF concentration is not correct. The
engine may derate.
There is a configuration parameter in the electronic
service tool called "Aftertreatment #1 DEF Quality
Sensor Installation Status" that must be programmed
to "Installed" . The parameter is factory password
protected. The DEF tank header with the DEF quality
sensor is a data link type sensor.
This document has been printed from SPI2. NOT FOR RESALE
Coolant Diverter Valve
Illustration 27
Typical example
(1) Outlet connection
(2) Electrical connection
(3) Inlet connection
(4) Flow direction indicator
The coolant diverter valve is mounted to the
application. The coolant diverter valve is a normally
closed valve. The valve is a unidirectional flow valve.
The system is used to thaw the frozen DEF fluid in
the DEF tank before dosing occurs. Warming the
system is achieved by taking warm coolant from the
engine and routing the coolant through the tank and
DEF pump. The coolant diverter valve will open when
the tank temperature needs to be increased. Once
the DEF tank temp is warm enough, the system will
start dosing. The usable temperature of the DEF is
between −10° to 55°C (14° to 131°F).
33
Engine Operation
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