Question 1

NOx emissions forming during peak cylinder pressures and temperatures are reduced by extending the:

Accepted Answer

A) ignition delay period" 
B) valve Timing" 
C) burn period 
D) injection timing" 
A) ignition delay period" 
B) valve Timing" 
C) burn period 
D) injection timing" C

Question 2

Under which of the following conditions is EGR typically disabled?

Accepted Answer

A) Heavy acceleration and high engine loads. 
B) After an active regeneration of the diesel particulate filter (DPF). 
C) Excessively high engine coolant temperatures. 
D) High barometric pressures. 
A) Heavy acceleration and high engine loads. 
B) After an active regeneration of the diesel particulate filter (DPF). 
C) Excessively high engine coolant temperatures. 
D) High barometric pressures. C

Question 3

The cooler bundle on the 2.8 L Duramax is made up of:

Accepted Answer

A) aluminum tubes" 
B) stainless steel tubes" 
C) steel tubes 
D) plastic tubes" 
A) aluminum tubes" 
B) stainless steel tubes" 
C) steel tubes 
D) plastic tubes" B

Question 4

Technician A says that EGR gas containing soot is present in all EGR systems. Technician B says that low-pressure EGR systems typically do not contain soot. Who is correct?

Accepted Answer

A) Technician A 
B) Technician B 
C) Both A and B 
D) Neither A nor B 
A) Technician A 
B) Technician B 
C) Both A and B 
D) Neither A nor B

Question 5

Technician A says that EGR systems monitor engine speed and load conditions to meter the correct amount of exhaust gas into the engine intake. Technician B says that during idle, cold weather, or engine operation, maximum EGR flow usually takes place. Who is right?

Accepted Answer

A) A only" 
B) B only" 
C) Both A and B 
D) Neither A nor B" 
A) A only" 
B) B only" 
C) Both A and B 
D) Neither A nor B"

Question 6

Technician A says that the oil used in the earliest EGR engines has a different API designation than oil used in engines with particulate filters. Technician B says that the oil used in engines equipped with particulate filters can be used in EGR engines. Who is correct?

Accepted Answer

A) Technician A 
B) Technician B 
C) Both A and B 
D) Neither A nor B 
A) Technician A 
B) Technician B 
C) Both A and B 
D) Neither A nor B

Question 7

Two technicians are describing how to inspect an EGR cooler for leaks. Technician A says that you use shop air pressure regulated to 50 psi to pressurize the cooler exhaust ports to check for cracks. Technician B says that after visually inspecting the engine for coolant leaks during a pressure test, the EGR cooler can be disconnected and removed. Who is right?

Accepted Answer

A) A only" 
B) B only" 
C) Both A and B 
D) Neither A nor B" 
A) A only" 
B) B only" 
C) Both A and B 
D) Neither A nor B"

Question 8

What is the purpose of a mass airflow (MAF) sensor on an EGR-equipped engine?

Accepted Answer

A) To adjust air-fuel ratios on OBD-II compliant vehicles. 
B) To meter the correct quantity of air required for combustion. 
C) To measure the quantity of EGR gas entering engine cylinders. 
D) To calculate precise air-fuel ratios. 
A) To adjust air-fuel ratios on OBD-II compliant vehicles. 
B) To meter the correct quantity of air required for combustion. 
C) To measure the quantity of EGR gas entering engine cylinders. 
D) To calculate precise air-fuel ratios.

Question 9

Which of the following is the EGR rate for a 2010 Navistar massive diesel engines without an SCR (selective catalyst reduction)?

Accepted Answer

A) 10-20%" 
B) 20-35%" 
C) 15-25% 
D) 35-50%" 
A) 10-20%" 
B) 20-35%" 
C) 15-25% 
D) 35-50%"

Question 10

To reduce NOx formation, which of the following combustion elements is replaced by EGR gas?

Accepted Answer

A) Nitrogen. 
B) Nitric oxide (NO). 
C) Oxygen. 
D) Carbon dioxide (CO₂). 
A) Nitrogen. 
B) Nitric oxide (NO). 
C) Oxygen. 
D) Carbon dioxide (CO₂).

Question 11

To reduce NOx formation, which of the following combustion elements is replaced by EGR gas?

Accepted Answer

A) Nitrogen." 
B) Nitric oxide (NO)." 
C) Oxygen. 
D) Carbon dioxide (CO₂)." 
A) Nitrogen." 
B) Nitric oxide (NO)." 
C) Oxygen. 
D) Carbon dioxide (CO₂)."

Question 12

When should the VGT vanes or nozzle move from a closed to an open position?

Accepted Answer

A) At idle" 
B) At full fuel" 
C) At wide open throttle 
D) At part throttle" 
A) At idle" 
B) At full fuel" 
C) At wide open throttle 
D) At part throttle"

Question 13

Which combination of combustion conditions produces the highest NOx emissions from diesel engines?

Accepted Answer

A) High cylinder temperatures and pressures. 
B) Rich air-fuel mixtures and low cylinder pressures. 
C) High cylinder pressures and lean air-fuel mixtures. 
D) Low soot and high cylinder temperature. 
A) High cylinder temperatures and pressures. 
B) Rich air-fuel mixtures and low cylinder pressures. 
C) High cylinder pressures and lean air-fuel mixtures. 
D) Low soot and high cylinder temperature.

Question 14

While two technicians are discussing possible causes of engine coolant loss, Technician A says the EGR cooler is likely cracked and leaking. Technician B says that a cracked EGR cooler would leak coolant into the intake manifold. Who is correct?

Accepted Answer

A) Technician A" 
B) Technician B" 
C) Both A and B 
D) Neither A nor B" 
A) Technician A" 
B) Technician B" 
C) Both A and B 
D) Neither A nor B"

Question 15

Which of the following is required for EGR system diagnostics?

Accepted Answer

A) Vacuum gauge" 
B) Vacuum pump" 
C) Ruler 
D) DMM (digital multimeter)" 
A) Vacuum gauge" 
B) Vacuum pump" 
C) Ruler 
D) DMM (digital multimeter)"

Question 16

How does EGR gas contribute to increased cylinder wear?

Accepted Answer

A) It chemically weakens hardened steel piston rings." 
B) It causes nitriding of piston rings." 
C) It contains abrasive soot. 
D) It retards injection timing." 
A) It chemically weakens hardened steel piston rings." 
B) It causes nitriding of piston rings." 
C) It contains abrasive soot. 
D) It retards injection timing."

Question 17

What does a temperature sensor combined with a delta P sensor measure?

Accepted Answer

A) EGR gas mass. 
B) Exhaust backpressure. 
C) Intake air mass. 
D) Gas density. 
A) EGR gas mass. 
B) Exhaust backpressure. 
C) Intake air mass. 
D) Gas density.

Question 18

EGR reintroduces exhaust gas into engine cylinders to reduce:

Accepted Answer

A) boost pressure" 
B) intake pressure" 
C) exhaust backpressure 
D) peak cylinder pressure" 
A) boost pressure" 
B) intake pressure" 
C) exhaust backpressure 
D) peak cylinder pressure"

Question 19

Two technicians are describing high-pressure cooled (HP-CEGR) EGR systems. Technician A says that an HP-CEGR system does not use a throttle plate to draw exhaust in, instead a VGT pressurizes exhaust gases high enough to push exhaust into the boosted air intake. Technician B says that cooled EGR gas redirected from the exhaust manifold is pressurized to overcome intake boost pressure called high-pressure cooled EGR (HP-CEGR). Who is right?

Accepted Answer

A) A only" 
B) B only" 
C) Both A and B 
D) Neither A nor B" 
A) A only" 
B) B only" 
C) Both A and B 
D) Neither A nor B"

Question 20

Which of the following is the EGR rate for a 2010 moderate diesel engines with an SCR (selective catalyst reduction)?

Accepted Answer

A) 10-20%" 
B) 20-35%" 
C) 15-25% 
D) 35-50%" 
A) 10-20%" 
B) 20-35%" 
C) 15-25% 
D) 35-50%"

NOx emissions forming during peak cylinder pressures and temperatures are reduced by extending the:

Under which of the following conditions is EGR typically disabled?

The cooler bundle on the 2.8 L Duramax is made up of:

Technician A says that EGR gas containing soot is present in all EGR systems. Technician B says that low-pressure EGR systems typically do not contain soot. Who is correct?

Technician A says that EGR systems monitor engine speed and load conditions to meter the correct amount of exhaust gas into the engine intake. Technician B says that during idle, cold weather, or engine operation, maximum EGR flow usually takes place. Who is right?

Technician A says that the oil used in the earliest EGR engines has a different API designation than oil used in engines with particulate filters. Technician B says that the oil used in engines equipped with particulate filters can be used in EGR engines. Who is correct?

What is the purpose of a mass airflow (MAF) sensor on an EGR-equipped engine?

Which of the following is the EGR rate for a 2010 Navistar massive diesel engines without an SCR (selective catalyst reduction)?

To reduce NOx formation, which of the following combustion elements is replaced by EGR gas?

To reduce NOx formation, which of the following combustion elements is replaced by EGR gas?

When should the VGT vanes or nozzle move from a closed to an open position?

Which combination of combustion conditions produces the highest NOx emissions from diesel engines?

While two technicians are discussing possible causes of engine coolant loss, Technician A says the EGR cooler is likely cracked and leaking. Technician B says that a cracked EGR cooler would leak coolant into the intake manifold. Who is correct?

Which of the following is required for EGR system diagnostics?

How does EGR gas contribute to increased cylinder wear?

What does a temperature sensor combined with a delta P sensor measure?

EGR reintroduces exhaust gas into engine cylinders to reduce:

Which of the following is the EGR rate for a 2010 moderate diesel engines with an SCR (selective catalyst reduction)?

Introduction to Diesel Engines

Diesel Engine Emissions

Cylinder Blocks and Crankshafts

Cylinder Components

Cylinder Heads and Valve Train Mechanisms

Diesel Engine Cooling and Lubrication Systems

Diesel Fuel and Low Pressure Fuel Systems

Functions of High Pressure Fuel Systems

Governors and Electronic Control Systems

Hydraulic Nozzles

Heui Injection Systems

Common Rail Fuel Systems

Air Induction and Crankcase Ventilation Systems

Fixed Geometry and Wastegated Turbochargers

Variable Geometry and Series Turbochargers

Exhaust Aftertreatment Systems

On Board Diagnostics

Filters

Exam 17: Exhaust Gas Recirculation

NOx emissions forming during peak cylinder pressures and temperatures are reduced by extending the:

Under which of the following conditions is EGR typically disabled?

The cooler bundle on the 2.8 L Duramax is made up of:

Technician A says that EGR gas containing soot is present in all EGR systems. Technician B says that low-pressure EGR systems typically do not contain soot. Who is correct?

Technician A says that EGR systems monitor engine speed and load conditions to meter the correct amount of exhaust gas into the engine intake. Technician B says that during idle, cold weather, or engine operation, maximum EGR flow usually takes place. Who is right?

Technician A says that the oil used in the earliest EGR engines has a different API designation than oil used in engines with particulate filters. Technician B says that the oil used in engines equipped with particulate filters can be used in EGR engines. Who is correct?

What is the purpose of a mass airflow (MAF) sensor on an EGR-equipped engine?

Which of the following is the EGR rate for a 2010 Navistar massive diesel engines without an SCR (selective catalyst reduction)?

To reduce NOx formation, which of the following combustion elements is replaced by EGR gas?

To reduce NOx formation, which of the following combustion elements is replaced by EGR gas?

When should the VGT vanes or nozzle move from a closed to an open position?

Which combination of combustion conditions produces the highest NOx emissions from diesel engines?

While two technicians are discussing possible causes of engine coolant loss, Technician A says the EGR cooler is likely cracked and leaking. Technician B says that a cracked EGR cooler would leak coolant into the intake manifold. Who is correct?

Which of the following is required for EGR system diagnostics?

How does EGR gas contribute to increased cylinder wear?

What does a temperature sensor combined with a delta P sensor measure?

EGR reintroduces exhaust gas into engine cylinders to reduce:

Which of the following is the EGR rate for a 2010 moderate diesel engines with an SCR (selective catalyst reduction)?

Introduction to Diesel Engines

Diesel Engine Emissions

Cylinder Blocks and Crankshafts

Cylinder Components

Cylinder Heads and Valve Train Mechanisms

Diesel Engine Cooling and Lubrication Systems

Diesel Fuel and Low Pressure Fuel Systems

Functions of High Pressure Fuel Systems

Governors and Electronic Control Systems

Hydraulic Nozzles

Heui Injection Systems

Common Rail Fuel Systems

Air Induction and Crankcase Ventilation Systems

Fixed Geometry and Wastegated Turbochargers

Variable Geometry and Series Turbochargers

Exhaust Aftertreatment Systems

On Board Diagnostics

Filters