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AO Study Material 2020 Test > DEF System > Flashcards

DEF System Flashcards

(91 cards)

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1
Q

In what year were Diesel engines required to comply with more stringent emissions standards?

A

2007

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2
Q

What 3 things do the stringent emissions standard reduce?

A

Soot (partially burned fuel)
Ash (partially burned oil)
Nitrogen Oxide (NOx)

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3
Q

What 6 emissions equipment and functions are used by Cummins?

A 
After treatment device (ATD)
Diesel oxidation catalyst (DOC)
Diesel particulate filter (DPF)
Selective catalyst reduction (SCR)
Diesel exhaust fluid (DEF)
Lamps and ECU with OBD
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4
Q

Where is the diesel oxidation catalyst (DOC) found?

A

Inside After Treatment Device (ATD)

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5
Q

Where is the diesel particulate filter (DPF) found?

A

Inside after treatment device (ATD)

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6
Q

Where is the selective catalyst reduction (SEC) found?

A

After the diesel exhaust fluid (DEF)

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7
Q

What did the after treatment device (ATD) replace?

A

Typical muffler, contains DOC and DPF

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8
Q

What does the diesel particulate filter (DPF) do?

A

Traps particulate matter, soot and ash

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9
Q

How does the DPF self clean to get rid of soot accumulation?

A

Through regeneration

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10
Q

What is a selective catalyst reduction (SCR) device?

A

A catalytic converters that uses vaporized exhaust fluid (DEF) to reduce nitrogen oxide emissions

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11
Q

What 2 names is DEF also known as?

A

Urea

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12
Q

What solutions does DEF contain?

A

32.5% urea and deonized water

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13
Q

What does DEF breakdown into?

A

Ammonia

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14
Q

What process does DEF breakdown into ammonia?

A

Chemical reaction in a decomposition reactor through hydrolysis

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15
Q

Where do the nitrogen oxide and ammonia pass into where a catalytic reaction take place converting nitrogen oxide into harmless nitrogen gas and water vapor?

A

The selective catalyst reduction device

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16
Q

Regeneration occurs naturally when exhaust is hot enough to burn off what?

A

Soot

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17
Q

Regeneration may require intervention by what 2 things in order to inject small amount of fuel into DOC, which raises exhaust temperatures enough to burn off accumulated soot?

A

By either the engine ECU or operator intervention

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18
Q

What do 2013 and later emissions require Diesel engines receiving an upgrade on which also includes a malfunction indicator lamp (MIL)?

A

Engine ECU with fully integrated OBD

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19
Q

What happens when the check engine light (engine warning) illuminated?

A

A non critical system fault with engine has occurred

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20
Q

Can the operator drive the vehicle to the end of their shift and call service to remedy the problem with check engine light on?

A

Yes

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21
Q

What does the stop engine indication light mean?

A

Serious engine fault that may result in engine damage, vehicle should be shut down as soon as possible

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22
Q

If you get a stop engine light, the engine should remain shut down until who can service it?

A

Authorized Cummins dealer

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23
Q

What does the malfunction indication light mean when it illuminates?

A

Fault has occurred on an emission related component

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24
Q

When you get a malfunction indicator light (MIL) the engine should remain shut down until who can service it?

A

Authorized Cummins dealer

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25
What should happen if the MIL and stop engine light illuminate?
Vehicle should be stopped as soon as safe to do so, serviced by authorized cummins dealer
26
What does it mean when the DPF light illuminates?
A regeneration is necessary
27
When the DPF light is solid, it means how much particulate build up?
Low to medium particulate build up
28
When the DPF light is solid the vehicle requires regen but should be able to complete its mission before a regen is performed, you should make sure that what switch is not activated?
Regen inhibit switch
29
When the DPF light is solid, initiate a DPF regen by switching to a more challenging duty cycle such as what 2 things?
Highway driving for at least 20 minutes or pumping (aerial operation) Perform a parked regen
30
When the DPF light flashes, it means how much particulate build up and regen should be done as soon as possible?
Medium to high levels
31
How do you perform a regen when the DPF light flashes (2 things)?
Switching to more challenging duty cycle or a parked regen
32
When the DPF light flashes with check engine light, it means how much particulate build up and requires regen immediately?
High level
33
How do you perform a regen when DPF light flashes and check engine light on?
Operator must perform parked regen Automatic regen will not initiate
34
What does it mean when the DPF light flashes with check and stop engine lights illuminated?
If a parked regen is not performed
35
What should be done if the DPF light flashes and the check and stop engine lights illuminate?
Vehicle should be stopped as soon as safe to do so and remain shut down until services by an authorized Cummins dealer
36
What does the high exhaust system temperature (HEST) indicate?
An active regeneration has been initiated and exhaust system temps are elevated above normal levels
37
The HEST light will remain on until exhaust temps have dropped below what degree?
977 degrees
38
The HEST light will remain on if the vehicle speed drops below the threshold of what mph?
5 mph
39
The HEST light will remain on until vehicle speed increases what mph back above the speed threshold and regen finishes?
3 mph
40
When does passive regeneration occur (3 instances), exhaust temp naturally get high enough to oxidize soot in DPF?
During normal engine operation At high engine speeds (highway) High loads
41
Is engine ECU or operator intervention required for passive regeneration?
No, no difference in vehicle performance during process
42
Does extra fuel and excessive exhaust temp occur during passive regeneration?
No
43
The DPF light may temporarily illuminate and extinguish if soot levels reach what level, but because conditions allow, the passive regeneration process reduces the soot load naturally?
Moderate high levels
44
What is active regeneration controlled by?
Engine ECU
45
When will active regeneration take place (3 instances)?
Truck is being driven Stationary truck operations During pumping operations (aerial)
46
When does the need for active regeneration occur more frequently?
Low speed Low load Stop and go conditions
47
How else can active regeneration take place?
Manually initiate a parked regeneration by using regen switch located within reach of driver
48
When will the automatic active regeneration occur?
DPF light illuminates, ECU looks for opportunity to regen Sufficient exhaust flow and temperature Speedometer showing 5 mph or higher, or pumping mode
49
How can automatic active regeneration be suspended?
Using regen inhibit switch
50
What type of temperatures occur during parked regeneration and could cause serious burns and injury?
High exhaust gas temperature at zero vehicle speed
51
True or false, do not perform parked regen in an enclosed area?
True
52
You should not sit in a parked vehicle for any extended amount of time with engine running, why?
Exhaust fumes could leak in cab and death can result
53
Can you perform a parked regen while connected to an exhaust extraction system (plymovent)?
No
54
What is another name for parked regen?
Stationary or manual regen, it’s an active regen performed by operator while parked
55
If a parked regen is attempted and engine speed does not increase, who should you contact for assistance?
Cummins dealer
56
What is the parked regen rpm?
900 rpm
57
Does the apparatus need to be taken out of service to complete a parked regen?
No
58
How do you perform a parked regen?
When DPF lamp on of flashing ``` Stop in safe location Trans in neutral Set parking brake Set safe zone around exhaust Foot off throttle Hold regen switch for 5 seconds Monitor area, stop engine if unsafe conditions ```
59
How long should you hold the regen switch down for parked regen?
5 seconds
60
How large of an area should you clear around exhaust during parked regen?
5 feet
61
If indoor regen, the exhaust discharge pipe must be rated at least at what degree?
1500 degrees
62
When performing a parked regen, park on surface that will not?
Melt or burn, clean concrete or gravel (not grass or asphalt)
63
To stop the regeneration process before completion what should you press?
``` Releasing parking brake Throttle pedal Brake pedal Regen inhibit switch Turn off engine ```
64
What lamp must be on for parked regen?
DPF light
65
How long will a parked regen last?
20-40 minutes depending on soot level
66
How long will exhaust temps stay high after regen completion?
3-5 minutes
67
After regen completions, if excessive soot and and DPF light is still on what should you do?
Repeat parked regen If DPF light still on, call for service
68
After completion of regen, HEST light will remain on until?
Temps drop below 977 | Vehicle speed exceeds 5 mph
69
Inhibiting or suspending regens too frequently can result in what?
Exhaust restriction Higher fuel consumption Engine performance loss due to soot build up in DPF
70
If DPF has reached system limits (DPF flash with check engine light) the operator needs to take action such as removing the truck from high load mission and?
Initiate an active or a parked regen
71
The regen inhibit switch can be used when regen is going to occur in?
A location or situation that is not ideal and must be postponed
72
The regen inhibit switch should not be used for normal operation it only used for?
Hazardous environments
73
Overuse of the regen inhibit switch will lead to more frequent need of?
Parked/stationary regen | Need for servicing or replacing DPF
74
Anytime the engine detects a need for regen, it looks for conditions such as what to start an active regen?
Engine speed | Temperature
75
DPF filters remove soot but ash remains in filter, what will illuminate along with a fault code will be set when ash removal is necessary?
CEL
76
Over time the DPF must be removed, disassembled and cleaned, the maintenance interval is what?
200,000-400,000 miles | 6,750 engine hours dependent on duty cycle, type of oil and oil consumption rate
77
What type of oil will maximize the DPF maintenance interval?
CES20081/AP1 CJ-4 oil
78
The SRC requires what fluid?
DEF
79
How many gallons does the DEF reservoir hold?
4 1/2
80
According to the logbook, DEF fluid should be refilled when?
When fueling with diesel fuel | At end of their shift
81
The DEF lamp will remain off between what levels?
Full and 38%
82
You will get a solid DEF light between what levels?
38%-12%
83
The DEF fluid light will flash between what levels?
Below 12%
84
The DEF light will flash and solid check engine light will appear at what level?
Below 5%
85
The DEF light will flash, solid check engine and MIL light when?
DEF tank empty and system can no longer maintain DEF pressure
86
The DEF light will flash, solid check engine, MIL and stop engine light will appear when?
DEF tank empty and ignored Engine intentionally shut down or extended idle
87
DEF will freeze at what degree?
11 degrees
88
What’s the minimum shelf life of DEF fluid?
12 months
89
DEF fluid should be stored at temperatures between?
10-90 degrees
90
On all 2007, 2010, and 2013 EPA Diesel engines, the exhaust temperature can reach what degree during an active regeneration cycle?
1350
91
Reduced exhaust diffuser (exhaust tip to lower exhaust gas temperatures as they exit tailpipe) can result in exhaust temperatures approaching what degree at the outlet during or shortly after DPF regeneration?
1200 degrees

AO Study Material 2020 Test (124 decks)

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