Question 1

What is the functional difference between C-EGR and I-EGR?

Accepted Answer

A)   C-EGR system run warmer
B)   I-EGR is managed within the cylinder head
C)   I-EGR costs more
D)   C-EGR systems must be managed by the engine ECME) C) and D)
F) B) and D)

Question 2

What would be a typical maximum intake restriction specification for a turbocharged diesel engine?

Accepted Answer

A)   15 inches H2O
B)   15 inches Hg
C)   25 inches H2O
D)   25 inches HgE) B) and C)
F) A) and B)

Question 3

When the unison ring in a variable nozzle (VN)  type turbocharger is moved, which of the following changes?

Accepted Answer

A)   vane pitch
B)   pulse frequency
C)   inlet flow area
D)   bypass flow areaE) B) and C)
F) None of the above A

Question 4

Which of the following is NOT part of the exhaust system?

Accepted Answer

A)   catalytic converter
B)   turbocharger
C)   pyrometer
D)   charge air coolerE) None of the above
F) All of the above

Question 5

What term does Detroit Diesel use to describe their compound turbocharger on DD-series engines?

Accepted Answer

A)   variable geometry (VG) 
B)   pulsed turbocharging
C)   direct drive turbocharging
D)   axial power turbine (APT) E) A) and B)
F) C) and D)

Question 6

Which of the following components usually makes detailed tuning of diesel engine intake manifolds unnecessary?

Accepted Answer

A)   charge air cooler
B)   precleaner
C)   positive air cleaner
D)   turbochargerE) B) and D)
F) A) and B)

Question 7

Which of the following is NOT an intake system component?

Accepted Answer

A)   charge air cooler
B)   air cleaner
C)   turbocharger
D)   catalytic converterE) B) and D)
F) A) and B)

Question 8

What happens when a wastegate actuator is in its default position?

Accepted Answer

A)   all exhaust gas bypasses the turbine housing
B)   all exhaust gas is routed through the turbine housing
C)   all intake air bypasses the charge air cooler
D)   all intake air bypasses the compressor housingE) All of the above
F) None of the above

Question 9

What would be a typical maximum intake restriction specification for a naturally aspirated diesel engine?

Accepted Answer

A)   15 inches H2O
B)   15 inches Hg
C)   25 inches H2O
D)   25 inches HgE) All of the above
F) C) and D) A

Question 10

What should be used to measure the radial play of a turbine shaft?

Accepted Answer

A)   micrometer
B)   thickness gauges
C)   digital calipers
D)   dial indicatorE) B) and C)
F) A) and D)

Question 11

Which of the following specs is the usual start-test spec when testing an air-to-air, boost air heat exchanger?

Accepted Answer

A)   5 psi
B)   15 psi
C)   30 psi
D)   50 psiE) A) and B)
F) All of the above

Question 12

In a sound absorption type muffler, what is sonic energy converted to?

Accepted Answer

A)   friction, then heat
B)   mechanical vibration
C)   pressure
D)   noiseE) All of the above
F) A) and B)

Question 13

What is used to cool an air-to-air charge air cooler?

Accepted Answer

A)   ram air
B)   engine coolant
C)   engine lubricant
D)   engine fanE) All of the above
F) A) and D) A

Question 14

Which of the following would ensure that the breathing efficiency of a pair of intake valves on one diesel engine cylinder was identical?

Accepted Answer

A)   air to air cooler
B)   crossflow valve configuration
C)   tune intake manifold
D)   parallel port valve configurationE) A) and C)
F) A) and B)

Question 15

Which of the following is the most accurate method of checking out an air filter between service intervals?

Accepted Answer

A)   remove and test with a trouble light
B)   test with a manometer
C)   blow out with an air nozzle
D)   tap on floor to loosen dustE) A) and B)
F) B) and D)

Question 16

What is the function of the stainless steel liner used in the cylinder head exhaust tract of some diesel engine cylinder heads?

Accepted Answer

A)   insulation to maximize rejected heat discharge to the turbine housing
B)   helps protect service personnel from serious burns
C)   enables high sulfur fuel to be combusted in electronically controlled diesel engines
D)   all of the aboveE) A) and B)
F) A) and C)

Question 17

Technician A says that a DD axial power turbine (APT)  uses a constant geometry (CG)  turbine principle. Technician B says that Detroit Diesel claim their APT can add over 100 horsepower to engine output potential. Who is correct?

Accepted Answer

A)   Technician A only
B)   Technician B only
C)   Both A and B
D)   Neither A nor BE) A) and D)
F) B) and C)

Question 18

Which type of valve configuration is more likely to be used with quiescent combustion technology?

Accepted Answer

A)   parallel port
B)   series-parallel
C)   crossflow
D)   two valve per cylinderE) None of the above
F) A) and B)

Question 19

What is the critical flow area inside the turbine housing of a turbocharger known as?

Accepted Answer

A)   diffuser
B)   impeller gate
C)   volute
D)   turbine outletE) A) and B)
F) B) and C)

Question 20

What is the housing containing the muffler, catalytic converters, SCR, and diesel particulate filter (DPF)  known as?

Accepted Answer

A)   exhaust pipe
B)   engine silencer
C)   resonator housing
D)   exhaust gas aftertreatment canisterE) B) and C)
F) C) and D)

Exam 12: Engine Breathing

What is the functional difference between C-EGR and I-EGR?

Correct AnswerverifiedShow Answer

What would be a typical maximum intake restriction specification for a turbocharged diesel engine?

Correct AnswerverifiedShow Answer

When the unison ring in a variable nozzle (VN) type turbocharger is moved, which of the following changes?

Correct AnswerverifiedA

Which of the following is NOT part of the exhaust system?

Correct AnswerverifiedShow Answer

What term does Detroit Diesel use to describe their compound turbocharger on DD-series engines?

Correct AnswerverifiedShow Answer

Which of the following components usually makes detailed tuning of diesel engine intake manifolds unnecessary?

Correct AnswerverifiedShow Answer

Which of the following is NOT an intake system component?

Correct AnswerverifiedShow Answer

What happens when a wastegate actuator is in its default position?

Correct AnswerverifiedShow Answer

What would be a typical maximum intake restriction specification for a naturally aspirated diesel engine?

Correct AnswerverifiedA

What should be used to measure the radial play of a turbine shaft?

Correct AnswerverifiedShow Answer

Which of the following specs is the usual start-test spec when testing an air-to-air, boost air heat exchanger?

Correct AnswerverifiedShow Answer

In a sound absorption type muffler, what is sonic energy converted to?

Correct AnswerverifiedShow Answer

What is used to cool an air-to-air charge air cooler?

Correct AnswerverifiedA

Which of the following would ensure that the breathing efficiency of a pair of intake valves on one diesel engine cylinder was identical?

Correct AnswerverifiedShow Answer

Which of the following is the most accurate method of checking out an air filter between service intervals?

Correct AnswerverifiedShow Answer

What is the function of the stainless steel liner used in the cylinder head exhaust tract of some diesel engine cylinder heads?

Correct AnswerverifiedShow Answer

Technician A says that a DD axial power turbine (APT) uses a constant geometry (CG) turbine principle. Technician B says that Detroit Diesel claim their APT can add over 100 horsepower to engine output potential. Who is correct?

Correct AnswerverifiedShow Answer

Which type of valve configuration is more likely to be used with quiescent combustion technology?

Correct AnswerverifiedShow Answer

What is the critical flow area inside the turbine housing of a turbocharger known as?

Correct AnswerverifiedShow Answer

What is the housing containing the muffler, catalytic converters, SCR, and diesel particulate filter (DPF) known as?

Correct AnswerverifiedShow Answer

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