16 minute read
UREA SCR SYSTEM DIAGRAM
Urea Scr System Diagram
Function Of Urea Scr System
•Urea SCR system is a device which converts toxic nitrogen oxides (NOx) in the exhaust gas into harmless nitrogen and water.
•By spraying AdBlue/DEF into the exhaust gas, it decomposes and hydrolyzes to form ammonia (NH3) and the ammonia selectively reacts with nitrogen oxides for the conversion to nitrogen and water
FUNCTION OF AdBlue/DEF SUPPLY SYSTEM
1: AdBlue/DEF tank
2: AdBlue/DEF suction hose
3: AdBlue/DEF Pump
3A: Selector valve
3B: Pump
3C: AdBlue/DEF filter
3D: Pressure sensor
4: AdBlue/DEF return hose
5: AdBlue/DEF pressure hose
6: AdBlue/DEF injector
•AdBlue/DEF system is a system that injects AdBlue/DEF into mixing tube. This system consists of AdBlue/DEF tank (1), AdBlue/DEF hoses (2), (4), (5), AdBlue/DEF pump (3), and AdBlue/DEF injector (6).
•This system automatically starts operation after starting the engine.
•Since AdBlue/DEF freezes at -11 °C, this system has a heating function to thaw AdBlue/DEF and to prevent AdBlue/DEF from freezing.
AdBlue/DEF injection function
•AdBlue/DEF injection function is a function that injects AdBlue/DEF which is pressurized with AdBlue/DEF pump into mixing tube.
•Engine controller controls the injection volume by using AdBlue/DEF injector.
•Engine controller determines the injection volume by the information from the turbocharger outlet NOx sensor, SCR temperature sensor, and KDOC gas flow sensor while correcting it by ammonia sensor and SCR outlet NOx sensor.
•AdBlue/DEF injection is controlled according to the system temperature as well since the urea SCR system does not operate efficiently at low temperature. The temperature sensor is used for this monitoring.
•The engine controller commands to stop injection, and injector does not inject when a failure code is displayed due to an abnormality which is detected by any sensor which determines the injection volume.
•The urea in AdBlue/DEF are deposited in the mixing tube, and it may stick to block the passage if an abnormality occurs.
AdBlue/DEF purge function
•AdBlue/DEF purge function is a function that purges remaining AdBlue/DEF in AdBlue/DEF system automatically after engine is stopped.
•It purges AdBlue/DEF from inside of injector or pump in order to prevent blocking or sticking by deposited urea in AdBlue/DEF, or malfunction of equipment caused by frozen AdBlue/DEF in cold weather. For this reason, the system operates for few minutes even after engine is stopped, but this is not an abnormality.
Notice
Do not turn off the battery disconnect switch while purging AdBlue/DEF.
AdBlue/DEF function of thawing and preventing from freezing
•Thawing control system has the thawing mode and freeze prevention mode.
•Thawing mode is the function to thaw the frozen AdBlue/DEF.
•After starting engine, if the engine controller judges that AdBlue/DEF must be thawed, this function automatically heats the system.
•At this time, pressure control of AdBlue/DEF pump and injection of AdBlue/DEF are not performed until the thawing is completed.
•Freeze prevention mode is the function to keep AdBlue/DEF warm to prevent it from freezing.
•This function automatically heats the system to prevent it from freezing while operating the machine, if engine controller judges that AdBlue/DEF could be frozen.
•This function stops the pressure control of AdBlue/DEF pump and injection of AdBlue/DEF if it judges that AdBlue/DEF is frozen while operating the machine.
•Thawing and freeze prevention are controlled by sensor, and the control sensors vary by devices which AdBlue/DEF system consists of. The following table shows the relationship between the object devices of thawing control, heating system, and control sensors for each mode.
Object devices of thawing control, heating system, and control sensors for each mode
When the engine room temperature sensor is equipped
Heating system Thawing modeFreeze prevention mode
AdBlue/DEF suction hose and return hoses
AdBlue/DEF pressure hose (lowtemperature side)
AdBlue/DEF pressure hose (hightemperature side)
Heater around hose
Ambient temperature sensor
Ambient temperature sensor
Heater around hose Engine room temperature sensor Engine room temperature sensor
AdBlue/DEF pump Pump built-in heater AdBlue/DEF pump temperature sensor
AdBlue/DEF tank Circulation of coolant AdBlue/DEF tank temperature sensor
When the engine room temperature sensor is not equipped
AdBlue/DEF suction hose and return hoses
AdBlue/DEF pressure hose
Ambient temperature sensor
AdBlue/DEF tank temperature sensor
Heating system Thawing modeFreeze prevention mode
Heater around hose Ambient temperature sensor
AdBlue/DEF pump Pump built-in heater AdBlue/DEF pump temperature sensor
AdBlue/DEF tank Circulation of coolant AdBlue/DEF tank temperature sensor
Inducement Strategy
Ambient temperature sensor
Ambient temperature sensor
AdBlue/DEF tank temperature sensor
•The purpose of inducement is to prompt the operator to perform maintenance or repair on the emissions control system.
•Inducement strategy is a control action to ensure prompt correction of various failures in the engine emissions control system. It requires actions to limit engine performance and defines required indication such as warning lamps and messages, as well as alarms while the control actions are imposed. The warning steps of Inducement are different between for North America and for European Union.
•The categories of abnormalities that have triggered Inducement are displayed on the “SCR Information” screen of the machine monitor.
INDUCEMENT STRATEGY WHEN THE AdBlue/DEF LEVEL IN THE TANK BECOMES LOW (FOR NORTH AMERICA)
•When the AdBlue/DEF level in the tank becomes low, AdBlue/DEF level caution lamp on the machine monitor lights up, the Audible alert sounds, the action level is displayed and Inducement strategy including engine power deration is activated.
•The Inducement strategy progresses in 5 levels from Warning, Escalated Warning, Mild Inducement, Severe Inducement and Final Inducement.
•Up to the start of Severe Inducement the start of each warning step is triggered by the amount of AdBlue/DEF in the AdBlue/DEF tank. Final Inducement starts at 1 hour after the start of Severe Inducement if the machine continues its operation without adding AdBlue/DEF into the tank, and reduces the engine speed to low idle and keeps it at low idle.
•The Inducement strategy status can be checked on “SCR Information” screen of the user menu.
•The table shows warning indications and engine power derations by each Inducement strategy status.
Status
1Warning
AdBlue/DEF level (*1) (AdBlue/DEF level gauge)
10% (The bottom two gradations light on)
Machine monitor Engine deration (*3) Message of SCR Information
AdBlue/DEF level caution lamp (Action level)
Tone of audible alert Activated failure code (*2)
2 Escalated Warning (Warning 2)
5% (Within the gradation of the second from the bottom )
1: DEF low level warning appears.
2: Without treatment, engine power will be derated.
Red No sound
CA3497 (AdBlue/DEF level low error 1)
No deration
Red Triplet (*4) Short intermittently (*5)
CA3498 (AdBlue/DEF level low error 2)
No deration
3
Mild Inducement (Inducement 1)
2.5% (The gradation of the end of the bottom lights on)
3: Engine power is under deration.
4
Severe Inducement (Inducement 2)
0% (All gradations lights off)
4: Engine power is under heavy deration.
5
Final Inducement (Inducement 3)
Not remaining in the tank (*6) (All gradations lights off)
5: Engine is running at low idle.
Red Long intermittently
CA1673 (AdBlue/DEF level low error 3)
Torque: over 25% Red
Red
Continuously
CA1673 CA3547 (AdBlue/DEF level low error 4)
Torque: 50% and RPM: 40% Red
Continuously
CA1673 CA3547 AS00ZK (AdBlue/DEF level low error 5)
Engine speed is fixed to low idle Red
*1: It is shown the value of Monitoring ID 19111: “AdBlue/DEF Level Corrected”.
*2: These failure codes are displayed on “Current Abnormality” in the operator mode, or “Abnormality Record” in the service mode. For the failure codes, see TROUBLESHOOTING, “TROUBLESHOOTING POINTS FOR UREA SCR SYSTEM”.
*3: These percentages show a torque reduction ratio from the full torque curve, and a speed reduction ratio from the rated speed.
*4: Construction equipment with crawler
*5: Construction equipment with wheel
*6: After progressed “Severe Inducement” the status advances to “Final Inducement” with in 1 hour.
INDUCEMENT STRATEGY WHEN ABNORMALITY IS FOUND IN THE UREA SCR SYSTEM DEVICES (FOR NORTH AMERICA)
•AdBlue/DEF system caution lamp lights up on machine monitor, and an action level is displayed when an abnormality occurs in quality in AdBlue/DEF or in urea SCR system. In addition to the caution by the AdBlue/DEF system caution lamp, alarm sounds as time passes after the abnormality occurred. Then, inducement strategy starts so that the engine output is lowered.
•The Inducement strategy status and the categories of abnormalities can be checked on the “SCR Information” screen of the machine monitor.
•The table shows warning indications and engine power derations by each Inducement strategy status.
4
Status
Elapsed time (*1)
Machine monitor
5
Severe Inducement (Inducement 2)
4 hours
Final Inducement (Inducement 3)
Until repairing
4: Engine power is under heavy deration.
Caution lamp (Action level)
Tone of audible alert
Failure code for abnormality (*2),(*3)
Red Continuously CA3571 CB3571
Failure code for Inducement strategy status (*4)
Engine deration (*5) Message of SCR Information
5: Engine is running at low idle.
Torque: 50% and RPM: 40% Red
Red Continuously
AS00R4 (Inducement 2 (SCR Device Abnormality))
CA3571 CB3571
AS00R5 (Inducement 3 (SCR Device Abnormality))
Engine speed is fixed to low idle Red
*1: Elapsed time of each stage describes an accumulated time advancing to the next stage after starting “Warning”stage. Final Inducement is not cleared till abnormality is repaired.
*2: These failure codes are displayed on “Current Abnormality” in the operator mode, or “Abnormality Record” in the service mode. The failure code shown here is an example of failure code which is displayed on the machine monitor when an abnormality occurs. For the failure codes, see TROUBLESHOOTING, “TROUBLESHOOTING POINTS FOR UREA SCR SYSTEM”.
*3: The failure code which starts with CB may be displayed for the machine equipped with aftertreatment devices branching off to 2 lines.
*4: These failure codes are displayed on “Current Abnormality” in the operator mode, or “Abnormality Record” in the service mode.
*5: These percentages show a torque reduction ratio from the full torque curve, and a speed reduction ratio from the rated speed.
*6: Construction equipment with crawler
*7: Construction equipment with wheel
Inducement Strategy When Abnormality Is Found In The
TEM BY THE UREA SCR SYSTEM (FOR NORTH AMERICA)
KDOC SYS-
•The Inducement strategy is different if Inducement is triggered by abnormalities in KDOC. Although the total steps are the same and 5, warning indications are different and engine power deration (Over 25% torque reduction) starts from that of “Warning”.
•The table shows warning indications and engine power derations by each Inducement strategy status.
10 Structure And Function Function Of Urea Scr System
Machine monitor
Status
Elapsed time (*1)
1Warning1 hour
2 Escalated Warning (Warning 2) 2 hours
3
Mild Inducement (Inducement 1)
3 hours
1: Please inspect and maintain SCR system.
Caution lamp (Action level)
Tone of audible alert
Failure code for abnormality (*2)
Failure code for Inducement strategy status (*3)
Engine deration (*4) Message of SCR Information
Red Long intermittently CA5391No indication
Torque: over 25%
2: Without treatment, engine power will be derated.
Triplet (*5) Short intermittently (*6)
CA5391
AS00R2 (Warning 2 (SCR Device Abnormality))
Torque: over 25%
3: Engine power is under deration.
Long intermittently CA5391
AS00R3 (Inducement 1 (SCR Device Abnormality))
Torque: over 25%
4
Severe Inducement (Inducement 2)
4 hours
4: Engine power is under heavy deration.
AS00R4 (Inducement 2 (SCR Device Abnormality))
Torque: over 50% and RPM: over 40%
5
Final Inducement (Inducement 3)
Until repairing
5: Engine is running at low idle.
AS00R5 (Inducement 3 (SCR Device Abnormality))
Engine speed is fixed to low idle
*1: Elapsed time of each stage describes an accumulated time advancing to the next stage after starting “Warning”stage. Final Inducement is not cleared till abnormality is repaired.
*2: These failure codes are displayed on “Current Abnormality” in the operator mode, or “Abnormality Record” in the service mode. The failure code shown here is an example of failure code which is displayed on the machine monitor when an abnormality occurs. For the failure codes, see TROUBLESHOOTING, “TROUBLESHOOTING POINTS FOR UREA SCR SYSTEM”.
*3: These failure codes are displayed on “Current Abnormality” in the operator mode, or “Abnormality Record” in the service mode.
*4: These percentages show a torque reduction ratio from the full torque curve, and a speed reduction ratio from the rated speed.
*5: Construction equipment with crawler
*6: Construction equipment with wheel
FUNCTION OF TEMPORARY RESTORATION FROM INDUCEMENT (FOR NORTH AMERICA)
•Temporary Restoration from Inducement is one of the Inducement strategies allowed to be included in Urea SCR systems. In case the Urea SCR system advances to “Severe Inducement”, engine power is derated heavily. This may cause difficulties of moving the machine to a safe place for adding AdBlue/DEF or troubleshooting and correcting abnormalities of the Urea SCR system. For temporary remedies from these difficulties the operator can restore engine power for a short time to the deration of “Mild Inducement” through the machine monitor. Note that “Temporary Restoration from Inducement” does not regain full engine power.
•“Temporary Restoration from Inducement” can be activated only when the Urea SCR system is in “Severe Inducement”. The maximum duration is limited to 30 minutes in each restoration operation, and 3 operations are allowed, but “Temporary Restoration from Inducement” is turned off whenever the system advances to “Final Inducement” even if either 30 minutes or 3 operations are not used up. All the abnormalities of the Urea SCR system need to be corrected to regain another restoration capability.
•If all the abnormalities of the Urea SCR system are not corrected when the system is in “Severe Inducement”, the system advances to “Final Inducement” in 1 hour after “Severe Inducement” started and engine speed will be fixed to low idle to disable practical machine operation.
•To activate Temporary Restoration, follow the procedures described below.
Remark
For the operating procedure on this function, refer to “TEMPORARY RESTORATION FROM INDUCEMENT” on the OPERATION section in the Operation and Maintenance Manual.
INDUCEMENT STRATEGY FOR ABNORMALITY RECURRENCE WITHIN 40 HOURS (FOR NORTH AMERICA)
•The Urea SCR system continuously monitors its operation conditions and stores information on inappropriate operations including malfunctions.
•The stored information is utilized to monitor recurrences of abnormalities, “Abnormality Counter”. “Abnormality Counter” is required by the authorities. The abnormality counting spans 40 hours and it monitors the abnormalities that trigger Inducement other than the amount of AdBlue/DEF in the tank.
•If another abnormality/abnormalities is detected within 40 hours after the previous abnormalities were corrected, regardless of the level of the previous Inducement and whether the new abnormality/abnormalities is the same as the previous ones or not, it is judged as a recurrence.
•If a recurrence occurs, the Inducement strategy will be activated and starts from “Severe Inducement”.
•The duration of “Severe Inducement” in the recurrence is limited to 30 minutes. If the abnormalities are not corrected while Inducement is in “Severe Inducement (30 minutes)”, Inducement will advance to “Final Inducement” and engine speed will be fixed to low idle to disable practical machine operation.
INDUCEMENT STRATEGY WHEN THE AdBlue/DEF LEVEL IN THE TANK BECOMES LOW (FOR EUROPEAN UNION)
•When the AdBlue/DEF level in the tank becomes low, AdBlue/DEF level caution lamp on the machine monitor lights up, the Audible alert sounds, the action level is displayed and Inducement strategy including engine power deration is activated.
•The Inducement strategy progresses in 4 levels from Warning, Continuous Warning, Low-Level Inducement, and Severe Inducement.
•Up to the start of Severe Inducement the start of each warning step is triggered by the amount of AdBlue/DEF in the AdBlue/DEF tank.
•The Inducement strategy status can be checked on “SCR Information” screen of the user menu.
•The table shows warning indications and engine power derations by each Inducement strategy status.
FUNCTION OF UREA SCR SYSTEM
1Warning
10% (The bottom two gradations light on)
1: DEF low level warning appears.
10 Structure
2 Continuous Warning (Warning 2)
5% (Within the gradation of the second from the bottom )
Red Triplet (*4) Short intermittently (*5)
Red
Low-Level Inducement (Inducement 1)
2.5% (The gradation of the end of the bottom lights on)
Red
4
Severe Inducement (Inducement 2)
0% (All gradations lights off)
Continuously
(AdBlue/DEF level low error
2) No deration
CA1673
(AdBlue/DEF level low error
3)
Torque: 50% and RPM: 40% Red
*1: It is shown the value of Monitoring ID 19111: “AdBlue/DEF Level Corrected”.
*2: These failure codes are displayed on “Current Abnormality” in the operator mode, or “Abnormality Record” in the service mode. For the failure codes, see TROUBLESHOOTING, “TROUBLESHOOTING POINTS FOR UREA SCR SYSTEM”.
*3: These percentages show a torque reduction ratio from the full torque curve, and a speed reduction ratio from the rated speed.
*4: Construction equipment with crawler
*5: Construction equipment with wheel
INDUCEMENT STRATEGY WHEN ABNORMALITY IS FOUND IN THE AdBlue/DEF QUALITY OR IN THE UREA SCR SYSTEM DEVICES (FOR EUROPEAN UNION)
•The Inducement strategy status and the categories of abnormalities can be checked on the “SCR Information” screen of the machine monitor.
•The table shows warning indications and engine power derations by each Inducement strategy status.
Machine monitor
Status Elapsed time (*1)
1Warning5 hours
2 Continuous Warning (Warning 2) 10 hours
3
Low-Level Inducement (Inducement 1)
20 hours
4
Severe Inducement (Inducement 2)
Until repairing
AdBlue/DE F system caution lamp (Action level)
Tone of audible alert
Failure code for abnormality (*2),(*3)
Failure code for Inducement strategy status (*4)
Engine deration (*5) Message of SCR Information
1: Please inspect and maintain SCR system.
Yellow No sound
CB3571 No indicationNo deration Yellow
Yellow
2: Without treatment, engine power will be derated.
Triplet (*6) Short intermittently (*7)
AS00R2 (Warning 2 (SCR Device Abnormality))
No deration
3: Engine power is under deration.
Long intermittently
AS00R3 (Inducement 1 (SCR Device Abnormality))
Torque: over 25%
4: Engine power is under heavy deration.
AS00R4 (Inducement 2 (SCR Device Abnormality))
Torque: 50% and RPM: 40%
*1: Elapsed time of each stage describes an accumulated time advancing to the next stage after starting “Warning” stage. Final Inducement is not cleared till abnormality is repaired.
*2: These failure codes are displayed on “Current Abnormality” in the operator mode, or “Abnormality Record” in the service mode. The failure code shown here is an example of failure code which is displayed on the machine monitor when an abnormality occurs. For the failure codes, see TROUBLESHOOTING, “TROUBLESHOOTING POINTS FOR UREA SCR SYSTEM”.
*3: The failure code which starts with CB may be displayed for the machine equipped with aftertreatment devices branching off to 2 lines.
*4: These failure codes are displayed on “Current Abnormality” in the operator mode, or “Abnormality Record” in the service mode.
*5: These percentages show a torque reduction ratio from the full torque curve, and a speed reduction ratio from the rated speed.
*6: Construction equipment with crawler
*7: Construction equipment with wheel
INDUCEMENT STRATEGY WHEN ABNORMALITY IS FOUND IN THE KDOC SYSTEM BY THE UREA SCR SYSTEM DEVICES (FOR EUROPEAN UNION)
•The Inducement strategy is different if Inducement is triggered by abnormalities in KDOC. Although the total steps are the same and 4, warning indications are different and engine power deration (Over 25% torque reduction) starts from that of “Warning”.
•The table shows warning indications and engine power derations by each Inducement strategy status.
3
Low-Level Inducement (Inducement 1)
20 hours
3: Engine power is under deration.
Red Red
Long intermittently CA5391
AS00R3 (Inducement 1 (SCR Device Abnormality))
Torque: over 25%
4
Severe Inducement (Inducement 2)
Until repairing
4: Engine power is under heavy deration.
Red Continuously CA5391
Red Red
AS00R4 (Inducement 2 (SCR Device Abnormality))
Torque: over 50% and RPM: over 40%
*1: Elapsed time of each stage describes an accumulated time advancing to the next stage after starting “Warning”stage. Final Inducement is not cleared till abnormality is repaired.
*2: These failure codes are displayed on “Current Abnormality” in the operator mode, or “Abnormality Record” in the service mode. The failure code shown here is an example of failure code which is displayed on the machine monitor when an abnormality occurs. For the failure codes, see TROUBLESHOOTING, “TROUBLESHOOTING POINTS FOR UREA SCR SYSTEM”.
*3: These failure codes are displayed on “Current Abnormality” in the operator mode, or “Abnormality Record” in the service mode.
*4: These percentages show a torque reduction ratio from the full torque curve, and a speed reduction ratio from the rated speed.
*5: Construction equipment with crawler
*6: Construction equipment with wheel
INDUCEMENT STRATEGY WHEN ABNORMALITY IS FOUND IN THE EGR SYSTEM BY THE UREA SCR SYSTEM DEVICES (FOR EUROPEAN UNION)
•The Inducement strategy is different if Inducement is triggered by abnormalities in EGR. Although the total steps are the same and 4, warning indications are different and engine power deration (Over 25% torque reduction) starts from that of “Warning”.
•The table shows warning indications and engine power derations by each Inducement strategy status.
Machine monitor
Status
Elapsed time (*1)
1Warning5 hours
2 Continuous Warning (Warning 2) 10 hours
3
Low-Level Inducement (Inducement 1)
20 hours
1: Please inspect and maintain SCR system.
Caution lamp (Action level)
Red
Tone of audible alert
Failure code for abnormality (*2)
Failure code for Inducement strategy status (*3)
Engine deration (*4) Message of SCR Information
2: Without treatment, engine power will be derated.
3: Engine power is under deration.
Torque: over 25% Red
Red
Yellow Red
Long intermittently CA2272No indication
Red
Triplet (*5) Short intermittently (*6)
CA2272
AS00R2 (Warning 2 (SCR Device Abnormality))
Torque: over 25%
Long intermittently CA2272
AS00R3 (Inducement 1 (SCR Device Abnormality))
Torque: over 25%
4
Severe Inducement (Inducement 2)
Until repairing
4: Engine power is under heavy deration.
Continuously CA2272
AS00R4 (Inducement 2 (SCR Device Abnormality))
Torque: over 50% and RPM: over 40%
*1: Elapsed time of each stage describes an accumulated time advancing to the next stage after starting “Warning”stage. Final Inducement is not cleared till abnormality is repaired.
*2: These failure codes are displayed on “Current Abnormality” in the operator mode, or “Abnormality Record” in the service mode. The failure code shown here is an example of failure code which is displayed on the machine monitor when an abnormality occurs. For the failure codes, see TROUBLESHOOTING, “TROUBLESHOOTING POINTS FOR UREA SCR SYSTEM”.
*3: These failure codes are displayed on “Current Abnormality” in the operator mode, or “Abnormality Record” in the service mode.
*4: These percentages show a torque reduction ratio from the full torque curve, and a speed reduction ratio from the rated speed.
*5: Construction equipment with crawler
*6: Construction equipment with wheel
FUNCTION OF TEMPORARY RESTORATION FROM INDUCEMENT (FOR EUROPEAN UNION)
•Temporary Restoration from Inducement is one of the Inducement strategies allowed to be included in Urea SCR systems. In case the Urea SCR system advances to “Severe Inducement”, engine power is derated heavily. This may cause difficulties of moving the machine to a safe place for adding AdBlue/DEF or troubleshooting and correcting abnormalities of the Urea SCR system. For temporary remedies from these difficulties the operator can restore engine power for a short time to the deration of “Low-Level Inducement” through the machine monitor. Note that “Temporary Restoration from Inducement” does not regain full engine power.
•“Temporary Restoration from Inducement” can be activated only when the Urea SCR system is in “Severe Inducement”. The maximum duration is limited to 30 minutes in each restoration operation, and 3 operations are allowed. All the abnormalities of the Urea SCR system need to be corrected to regain another restoration capability.
•To activate Temporary Restoration, follow the procedures described below. REMARK
For the operating procedure on this function, refer to “TEMPORARY RESTORATION FROM INDUCEMENT” on the OPERATION section in the Operation and Maintenance Manual.
