Brainscape's Knowledge GenomeTM

Browse over 1 million classes created by top students, professors, publishers, and experts.


See full index

EMS-D All Chapters Studied > Week 4, Light Duty Diesel Emissions > Flashcards

Week 4, Light Duty Diesel Emissions Flashcards

1
Q
  • Liquid and solid particles emitted from the engine exhaust and crankcase
  • Black carbon results in soot emissions; eliminated with newer diesel engines
  • Regulated and classified by particulate size in four categories
A

Particulate Matter

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
2
Q

Chassis ________________ measure emissions based on distance travelled by the complete vehicle

A

Dynamometers

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
3
Q

What is a common method to measure smoke density of diesel engine exhaust?

A

Opacity Testing

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
4
Q
  • Inadequate combustion time
  • Improperly mixed fuel and air
  • Coarse spray droplets
  • Insufficient combustion heat
  • Fuel pressure too low

These are all common causes of…

A

Incomplete combustion

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
5
Q

Regulating _______ (a naturally occurring component in diesel fuel), it enables sophisticated exhaust emissions’ aftertreatment

A

Sulfur

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
6
Q

High fuel sulfur content destroys ability of sulfate production devices to convert _________ emissions to __________ emissions

A

Noxious (harmful); Nonharmful

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
7
Q

Diesel engines are governed at relatively ____ engine speeds

A

Low

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
8
Q

First standards to reduce diesel emissions were introduced in _______

A

1970

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
9
Q

Diesel fuel sulfur content was reduced to __% in 1993

A

1

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
10
Q

Prior to 2007, emission reduction was accomplished in the ______________

A

Cylinder

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
11
Q
  • Indicate the level of emission standard an engine was designed to achieve
  • Provides information about part replacement and adjustment procedures, software calibration files, and other relevant data that affects emissions
A

Emissions Decals

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
12
Q
  • Light duty: 110,000 miles or 10 years
  • Medium duty: 185,000 miles of 10 years
  • Heavy duty: 435,000 miles or 10 years

These are all examples of…

A

Useful life requirements

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
13
Q
  • Low and high pressure cooled EGR
  • Two-way oxidation converters
  • Diesel particulate filters
  • Etc.

These are all examples of…

A

EPA-07 Standards

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
14
Q

From 2004-2010, NOx emissions had to be reduced by _____

A

90%

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
15
Q

The biggest technical challenges with diesel catalysts are…

A
  • Cold exhaust temperatures
  • Excess air content in exhaust
How well did you know this?
1
Not at all
2
3
4
5
Perfectly
16
Q

A(n) _________________________________ causes oxygen to chemically combine with noxious emissions such as HC and CO

A

Oxidation catalytic converter

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
17
Q

_____________________ systems were introduced to help achieve a 90% reduction in NOx emissions

A

Selective catalytic reduction

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
18
Q

Oxidation process turns emissions into _____________

A

Water

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
19
Q

Oxidation converters consist of a stainless-steel canister called a _____________

A

Substrate

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
20
Q

Substrate in a catalyst has a washcoat of catalytic ________________________

A

Precious metals

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
21
Q

Diesel catalysts need a minimum temperature of _______ before O2 can oxidize

A

400°F

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
22
Q

Reduction of pungent diesel odor is a ______________

A

Byproduct

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
23
Q

Exhaust is diluted with air, which _________________ its temperature

A

Reduces

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
24
Q

Technology incorporates HC-trapping materials into a catalyst substrate called _______________

A

Zeolite

25
Q

Low-temperature oxidation catalysts begin to catalyze at approximately _______

A

360°F

26
Q

What component removes soot and other solid particles from diesel exhaust, rendering the exhaust completely smokeless?

A

DPF (Diesel Particulate Filter)

27
Q

DPF’s eliminate particles down to ___ nanometers

A

50

28
Q

Exhaust passed through a wall _____________ where gas can escape but PM is trapped

A

Flow filter

29
Q

When DPF’s eventually become clogged, _______________ clears out the filter

A

Regeneration

30
Q

Heat for regeneration either comes from ________________ or __________________

A

Exhaust gas; added fuel

31
Q

_________ Regeneration

  • Takes place 85% of the time
  • No fuel is added
  • Vehicle must be 30+mph for 20 minutes
A

Passive

32
Q

The DPF is heated by adding small amounts of fuel to the exhaust stream. A downstream oxidation converter produces heat through a catalytic reaction of the fuel

A

Active regeneration

33
Q

In active regeneration, exhaust temperatures can raise to over _______

A

1000°F

34
Q

A fault code is set when a soot load of ____ is reached

A

80%

35
Q

Late injection in the exhaust stroke can cause ___________ in engine oil

A

Fuel dilution

36
Q

__________ regeneration requires vehicle to be away from combustible material

A

Parked

37
Q

DPF catalyst substrate is available in different materials such as…

A
  • Cordierite
  • Silicon carbide
  • Metal foil
38
Q

What can accumulate inside a DPF? (result of burned oil)

A

Ash

39
Q

What is the process called where liquid urea is sprayed into exhaust stream to destroy NOx molecules?

A

SCR (Selective Catalytic Reduction)

40
Q

NOx ______________________ is a catalyst strategy for removing NOx in the low-temperature, oxygen-rich exhaust environment of diesel engines

A

Absorber technology

41
Q

Lean NOx refers to __________________

A

Oxygen content

42
Q

The process in which NOx emissions are temporarily stored in the catalyst and removed in a two-step process that introduces fuel-rich oxygen-depleted exhaust

A

NOx Adsorbing

43
Q

What are the two drawbacks in DeSOx reactions?

A
  • NAC aftertreatment requires increased fuel consumption
  • Sulfur deactivates NACs
44
Q

A variety of ______ are needed to make DPFs work

A

Sensors

45
Q

Which sensor measures exhaust pressure at DPF inlet and outlet and supplies that data to the ECM?

A

Differential pressure sensor

46
Q

Most DPFs use _______ temperature sensor

A

Three

47
Q

____ sensors do not provide closed-loop feedback to meter the correct amount of DEF, but can detect incorrect concentrations of DEF emitted by dosing injectors and other emission related faults

A

NOx

48
Q

What component produces NH3 in the engine exhaust using HC dosing, high EGR flow, and reduced oxygen content without fluid additives?

A

NAN/LNT components

49
Q
  • When DPF soot loading exceeds 80%, the driver should change driving conditions to initiate a DPF passive regeneration
  • If passive regeneration cannot be completed, an active regeneration must be done
  • Engine must e warm and left at low idle, parking brake applied, and DPF inhibit switch held

These are all necessary when performing an…

A

Active Regeneration Procedure

50
Q
  • Initiated using an electronic service tool or OEM software
  • Light-duty vehicles cannot be regenerated by dash switches
  • Heavy-duty vehicles may not be able to complete active regenerations

These are all necessary when performing a…

A

Forced DPF Regeneration

51
Q

____ will accumulate from engine oil and eventually DPF will need to be removed for service

A

Ash

52
Q

_________________________ is a major emission problem in diesel engines due to higher compression ratios, cylinder pressure, and temperatures

A

NOx formation

53
Q

EGR may incorporate the use of a ________________ to help draw in EGR gases

A

Throttle plate

54
Q

Provide the ECM with data about quantity of air and exhaust, conditions that enable and disable EGR flow, and diagnostic data for the OBD system

A

EGR System Input Sensors

55
Q

Engine speed and accelerator pedal position indicate how much EGR mass is required for engine; combined with intake manifold pressure and temperature and determines the weight of air entering the cylinders

A

EGR Mass calculations

56
Q

The OBD II system detects and measures whether correct EGR flow is enabled based on a reduction in airflow into the engine

A

MAF Sensor and EGR Flow Calculations

57
Q

EGR gas flows through a venturi, which has a sensor measuring the pressure on its inlet and outlet sides. Low flow produces a low differential, high flow produces a high differential. Combined with gas temperature data, an accurate measure of EGR flow can be achieved.

A

Pressure Differential Measurement of EGR Flow

58
Q

Exhaust gas temperature must be lowered to roughly 425°F before it enters the cylinder. An EGR cooler is a heat exchanger that transfers heat from EGR gas to the cooling system. All cooling system components must be able to withstand the additional heat load

A

EGR Coolers

59
Q

What tools are required for diagnosing an external, non-cooled EGR?

A
  1. Vacuum gauge
  2. Multimeter
  3. Scan tool

EMS-D All Chapters Studied (11 decks)

Brainscape helps you reach your goals faster, through stronger study habits.
© 2024 Bold Learning Solutions. Terms and Conditions