2010/05/06© MAN Diesel SE 2010/05/06© MAN Diesel Common Rail - Basic Training <1 >
Robert MeierEESI (Injection Systems)R&D Engineering Medium Speed
MAN Diesel & TurboCommon Rail – Basic Training
2010/05/06© MAN Diesel SE <19 >
Accumulator
Injection valveHigh pressure pump
High pressure pipes
Camshaft (3 loop cam)None return valve
Valve block
CR-BasicsSystem overview 48/60 CR
48/60 CR
2010/05/06© MAN Diesel SE
CR-BasicsHydraulic layout (simplified)
<20 >
referencewheel
5 bar
10 bar
Valve block
AccumulatorUnit
Injection valve
Valve group
High pressure pump
None return valve
Pickup
Pressure sensor
Pressure limiting valve
(high pressure)
Scavengingvalve
Accumulator
Pressure limiting valve
(low pressure)
2010/05/06© MAN Diesel SE
CR-BasicsPressure generation / control / release
<21 >
Low pressure 10 bar
Low pressure 5 bar
High pressure max. 1600 bar
Holding pressure 100 bar
referencewheel
5 bar
10 bar
2010/05/06© MAN Diesel SE
CR-BasicsPressure generation / control / release
<22 >
2010/05/06© MAN Diesel SE
CR-BasicsInjection process
<23 >
referencewheel
5 bar
10 bar
Low pressure 10 bar
Low pressure 5 bar
High pressure max. 1600 bar
Holding pressure 100 bar
2010/05/06© MAN Diesel SE
CR-BasicsInjection process
<24 >
2010/05/06© MAN Diesel SE
CR-BasicsScavenging process
<26 >
referencewheel
5 bar
10 bar
Low pressure 10 bar
Low pressure 5 bar
High pressure max. 1600 bar
Holding pressure 100 bar
2010/05/06© MAN Diesel SE < 30 >
Main ComponentsHigh Pressure Pump 48/40 CR
High pressure pump48/60 CR
Feature:
quantity controlled bythrottle valve
Note:
without electrical signal thethrottle valveis fully opened
Throttle valve
Valve solenoid
Delivery valve
Valve carrier
Mono block cylinder
Plunger
2010/05/06© MAN Diesel SE <32 >
Main componentsAccumulator
Valve groupControl valve carrier
Flow limiterTubular shell Pressure pipe
To HP pump,next accumulator,
valve block
To Injection valve
To non return valve
2010/05/06© MAN Diesel SE <33 >
Main componentsAccumulator
Flow limiterFunctionality
avoids permanent injection
Note:
after closing one time the flow limiter keeps closed until the next release of the rail pressure
Piston movement at each injection
2010/05/06© MAN Diesel SE <34 >
Main componentsAccumulator
Valve groupFunctionality
controls the injection
Note:
the 3/2 WV (main valve) is controlled by a 2/2 WV
2/2-wayvalve
3/2-wayvalve
Valvesolenoid
2010/05/06© MAN Diesel SE <35 >
Main componentsAccumulator – Function valve group
Begin of current feed – opening of 2/2 way-valve
pRailComponent movement
Spring force
Hydraulic forceFuel flow
2/2 way-valve opened
Pressure loss above the piston of the 3/2 way-valve; due to narrow feed bore chamber can not be refilled
2010/05/06© MAN Diesel SE <36 >
Main componentsAccumulator – Function valve group
Opening of 3/2 way-valve piston
pRail
Piston of the 3/2 way-valve moving up due to hydraulic force
Canal to cut off system blocked
Fuel flow to injection nozzle
To cut off system
Component movement
Spring force
Hydraulic forceFuel flow
2010/05/06© MAN Diesel SE <37 >
Main componentsAccumulator – Function valve group
Opening of the injection nozzle
pRailpRail
Injection nozzle needle opens when opening pressure reached
Component movement
Spring force
Hydraulic forceFuel flow
2010/05/06© MAN Diesel SE <38 >
Main componentsAccumulator – Function valve group
End of current feed – closing of 2/2 way-valve
pRailpRailpRail
Ball of 2/2 way-valve closes
Component movement
Spring force
Hydraulic forceFuel flow
2010/05/06© MAN Diesel SE <39 >
Main componentsAccumulator – Function valve group
pRail
Due to increasing pressure above the 3/2 way-valve’s piston the piston moves down
Canal from rail to injection nozzle is closed
Closing of 3/2 way-valve piston
Component movement
Spring force
Hydraulic forceFuel flow
2010/05/06© MAN Diesel SE <40 >
Main componentsAccumulator – Function valve group
Closing of injection nozzle
pRail
To cut off system
Pressure in injection pipe drops down
Injection nozzle needle closes, end of injection
Amount of fuel not injected leaves the valve group to the cut off system
Component movement
Spring force
Hydraulic forceFuel flow
2010/05/06© MAN Diesel SE
Main componentsNone return valve
<42 >
None return valve with volume adapterFunctionality
pressure discharge of the injection pipe
holding pressure to avoid cavitation
Volume fordamping
2010/05/06© MAN Diesel SE
Main componentsValve block
<44 >
Valve block
Valve blockFunctionality
Scavenging valve
Pressure limiting valve
Rail pressure sensors
2010/05/06© MAN Diesel SE
Main componentsValve block
<45 >
Scavenging valve Functionality
Scavenging
High pressure release(Emergency stop)
Carries the pressure sensors(Two redundant sensors)
Fuel return line
Rail pressure
2010/05/06© MAN Diesel SE
Main componentsValve block
<46 >
Pressure limiting valveFunctionality
Prevents the system fromoverpressure
Fuel return line Rail pressure
Mechanical pressure controlfor emergency operation mode
2010/05/06© MAN Diesel SE <55 >
Leakage
Note:All leakage cross sections of the high pressure pipes are connected to the leakage cross sections of the accumulators.
Leakage detection systemConcept
2010/05/06© MAN Diesel SE <57 >
Capacitive sensorFunctionality:
Locating of the affectedaccumulator
Leakage fitting
Accumulator
Leakage pipe
Capacitive sensor
Leakage detection systemConcept
2010/05/06© MAN Diesel SE <58 >
Detection screwsFunctionality:
Locating of the affected high pressure pipe
Leakage detection systemConcept
© MAN Diesel CR Importance of cleanness PrimeServ Academy 07.10.2009
Never remove screwed unions from the fuel high- pressure side of the common-rail system while the engine is running or immediately after stop
< 2 >
Warning notes
While the engine is running, the lines are constantly under a fuel pressure of up to 1600 bar
© MAN Diesel CR Importance of cleanness PrimeServ Academy 07.10.2009
After switching off the engine wait for at least two minutes for the pressure to drop.Press emergency stop to ensure that the scavenging valve
(flushing valve) is activated
< 4 >
Warning notes
Make sure that compressedair supply valve ( 7172) for the emergency stop remains open.
© MAN Diesel CR Importance of cleanness PrimeServ Academy 07.10.2009
The workplace must be absolutely clean.
Thoroughly clean the components you disassemble
Make sure your work clothes are clean before commencing work.
Adjacent workplaces must not cause contamination, raise dust etc. (eg grinding ).
Follow job and assembly instructions (Working cards)
Removed parts are to be handled as genuine spare parts, ie they are to be packed separately and the connections are to be closed up.
< 5 >
Cleanliness in CR injection systems
© MAN Diesel CR Importance of cleanness PrimeServ Academy 07.10.2009 < 6 >
Protective sleeve for hi pressure pipeCR - medium speed
When disassembling, immediately close up all connections with caps.
© MAN Diesel CR Importance of cleanness PrimeServ Academy 07.10.2009 < 7 >
Valve group CR-medium speed
All openingsmust beprotected
© MAN Diesel CR Importance of cleanness PrimeServ Academy 07.10.2009
Use only lint-free cleansing tissue
< 9 >
Cleansing tissue
© MAN Diesel CR Importance of cleanness PrimeServ Academy 07.10.2009 < 10 >
Should be avoided
Cleanliness in CR injection systems
© MAN Diesel CR Importance of cleanness PrimeServ Academy 07.10.2009 < 11 >
Protective sleeve - InjectorCR - medium speed
To avoid contamination with particles and mechanical damage of the sealing surfaces
© MAN Diesel CR Importance of cleanness PrimeServ Academy 07.10.2009 < 12 >
Common Rail components Sizes
© MAN Diesel CR Importance of cleanness PrimeServ Academy 07.10.2009 < 14 >
Particle on nozzle needle
Field findings
© MAN Diesel CR Importance of cleanness PrimeServ Academy 07.10.2009 < 15 >
Field findings
Contaminant at the needle seat
2010/05/06© MAN Diesel SE <66 >
12V 48/60 CRDiesel-electric drive
propulsion system
Thank you for your attention!
Common Rail System
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