Sensors and
Electric Devices
Electric Devices
Which device is controlled by a short voltage pulse (0…90VDC)?
àThe valve groups (nFSV5078)
Which component controls fuel flow to the injection valves?
The valve group.
What must be checked after replacing a valve group?
tightness of the rail
How much fuel must circulate across a running CR engine?
300% of its maximum fuel consumption.
Where does the leak-off from the valve groups go to?
Into the fuel, used for flushing the valve groups.
What does the code 2PT5076 stand for?
CR rail pressure sensor no. 2
What is the purpose of the throttle valves and where are they mounted?
Controlling the rail pressure
Mounted on high pressure pumps
What happens two minutes after the engine has been stopped (0 rpm)?
Flushing process starts.
What must be the fuel pressure at the engine inlet?
11-12bar
How is a break leakage detected?
- alarm by capacitive leakage sensor under the accumulators
- alarm by leakage sensor in monitoring tank
What will be the effect if the cable to 1FCV5075A breaks?
Throttle valve no. 1 is completely open
--> rail pressure goes up
--> possibly the PLV opens
What component makes a loud POP noise 2 minutes after shutdown?
The flushing valve
What is the purpose of installing a nut on the threaded pin of the flushing valve?
Securing the high pressure system, so it can't build up pressure.
What is the purpose of the "Rickmeier" valve and where is it mounted?
Keeps a differential pressure of 5-7bar between fuel supply and return line.
What will happen if the gasket between inlet and outlet of the throttle valve is defect?
Throttle valve is by-passed
--> no proper rail pressure regulation
--> PLV opens at engine start or stop
Which electric device reports an open pressure limiting valve?
The temperature element 1TE5081
This component reduces cavitation in the valve groups.
The cut-off valve (100bar).
The exhaust temperature on cylinder A5 drops suddenly.
Give three possible reasons!
valve group defect
control signal at valve group missing
injection valve blocked
flow limiter shut off
What will happen if the fuel pressure at the engine inlet is constantly to low?
Cavitation at the high pressure pumps and in the throttle valve increases.
You stop the engine and the rail pressure drops rapidly (>1500bar/min). No leakage alarms.
Which component might be damaged?
discharge valve of high pressure pump
check-valve for flushing operation
valve block
What will happen if the cable to 4TE1064-2 breaks?
Main bearing temperature to safety system
Sensor reading of alarm system will be shared
Do the cut-off valves produce a leak-off?
If yes: where does it go to?
If no: why not?
Yes.
It goes into the fuel return line.
Name 3 circumstances that would activate the flushing valve!
2 minutes after normal stop,
manual emergency-stop,
emergency shut-down by SaCoS
Why is the leak-off from high pressure pump and throttle valve guided through the solenoid of the throttle valve?
Lubrication of the anchor pin and flushing of the armature space.
Describe what would happen if both rail pressure sensors fail!
Controlled emergency operation.
SaCoSone will open the throttle valves to maximize fuel pressure to cause the PLV to open.
This will reduce rail pressure to a max of 1200 bar.
SaCoSone will limit the rail pressure to a value, read from a set-point table (800-1000bar) and request load reduction.