Question 1

Technician A says that most diesel engines used today have direct-injection combustion chambers. Technician B says that most diesel engines built today use multi-orifice spray nozzles. Who is correct?

Accepted Answer

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

Question 2

Not only are diesel emissions as clean as gasoline engine mandated for 2017, but they also emit a minimum of _______ fewer exhaust emissions.

Accepted Answer

A) 10-30%" 
B) 15-35%" 
C) 20-40% 
D) 40-60%"

Question 3

Which diesel engine combustion chamber design will produce the fastest coolant warm-up times?

Accepted Answer

A) Direct injection. 
B) Indirect injection. 
C) Two stroke. 
D) Hemispheric chamber.

Question 4

What are the CO2 emissions for a diesel engine?

Accepted Answer

A) 22.2 lb per gallon of fuel" 
B) 6.2 lb per gallon of fuel" 
C) 6.1 lb per gallon of fuel 
D) 20.2 lb per gallon of fuel"

Question 5

Which one of the following negative characteristics did NOT hinder the more widespread use of diesels?

Accepted Answer

A) Noisy engine operation" 
B) Poor hot weather start ability" 
C) Poor acceleration 
D) Strong exhaust odor"

Question 6

Which of the following best describes the term "ignition delay"?

Accepted Answer

A) The time required to raise the fuel pressure high enough to overcome compression pressure in a cylinder. 
B) The time lag from initial injection to actual ignition. 
C) The time required to heat up a glow plug. 
D) The time required for vaporized fuel to atomize.

Question 7

Technician A says increasing an engine's compression ratio will produce better fuel economy but less power output. Technician B says increasing an engine's compression ratio produces more power but increases fuel consumption. Who is correct?

Accepted Answer

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

Question 8

Which diesel engine combustion chamber design will produce the fastest coolant warm-up times?

Accepted Answer

A) Direct injection. 
B) Indirect injection. 
C) Two stroke. 
D) Hemispheric chamber.

Question 9

Which of the following is NOT a major characteristic of the IDI chamber?

Accepted Answer

A) Uses pre-combustion chamber formed in the cylinder head" 
B) IDI injectors use pintle-type nozzles" 
C) Uses a Mexican hat piston 
D) Chamber typically holds approximately 70% of the cylinder volume"

Question 10

IDIs are capable of a faster top engine rpm limit due to a higher degree of _____ to produce more rapid and even mixing of air and fuel.

Accepted Answer

A) fuel pressure" 
B) heat" 
C) turbulence 
D) compression"

Question 11

Technician A says a power stroke in a modern diesel engine uses only a single injection of fuel. Technician B says late-model diesel engines use multiple injection events during a combustion cycle. Who is correct?

Accepted Answer

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

Question 12

Which one of the following conditions will be produced by prolonged ignition delay in a diesel engine?

Accepted Answer

A) An engine knocking sound. 
B) Blue smoke. 
C) White smoke. 
D) Lower peak cylinder pressures.

Question 13

Technician A says that a knocking sound in a diesel is normal and is caused by a sharp rise in cylinder pressure. Technician B says that a knocking sound in a diesel is caused by ignition delay of fuel. Who is correct?

Accepted Answer

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

Question 14

Technician A says that without adequate turbulence, air and fuel will not mix, resulting in lost performance and efficiency and in increased emissions. Technician B says that the semi-toroidal shape of the DI chamber is designed to mix the air and fuel. Who is right?

Accepted Answer

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

Question 15

Technician A says the evaporation of diesel fuel from the tank of a diesel bus on a warm day produces more emissions than a car. Technician B says that diesel fuel does not produce a significant amount of emissions due to fuel evaporation. Who is correct?

Accepted Answer

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

Question 16

Inspiration for the engine concept may have occurred when Rudolf Diesel observed a demonstration of a device used to:

Accepted Answer

A) start fires" 
B) start steam engines" 
C) increase pressure 
D) increase power"

Question 17

Which diesel engine combustion chamber design will produce the fastest coolant warm-up times?

Accepted Answer

A) Direct injection." 
B) Indirect injection." 
C) Two stroke. 
D) Hemispheric chamber."

Question 18

Technician A says that high horsepower (kilowatts) is the most important attribute that an engine needs to pull heavy loads and accelerate quickly. Technician B says that high torque output is the most important attribute that an engine needs to quickly climb hills. Who is correct?

Accepted Answer

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

Question 19

Technician A says that diesel engines can produce more power because air and fuel are not mixed during the intake stroke. Technician B says that diesel engines produce more power because they use excess air to burn fuel. Who is correct?

Accepted Answer

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

Question 20

Technician A says that technological developments now enable the injection of gasoline directly into the combustion chamber of spark-ignited gasoline engines. Technician B says that gasoline direct-injection (GDI) engines inject gasoline near the beginning of the compression stroke. Who is right?

Accepted Answer

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

Exam 2: Introduction to Diesel Engines

Technician A says that most diesel engines used today have direct-injection combustion chambers. Technician B says that most diesel engines built today use multi-orifice spray nozzles. Who is correct?

Not only are diesel emissions as clean as gasoline engine mandated for 2017, but they also emit a minimum of _______ fewer exhaust emissions.

Which diesel engine combustion chamber design will produce the fastest coolant warm-up times?

What are the CO₂ emissions for a diesel engine?

Which one of the following negative characteristics did NOT hinder the more widespread use of diesels?

Which of the following best describes the term "ignition delay"?

Technician A says increasing an engine's compression ratio will produce better fuel economy but less power output. Technician B says increasing an engine's compression ratio produces more power but increases fuel consumption. Who is correct?

Which diesel engine combustion chamber design will produce the fastest coolant warm-up times?

Which of the following is NOT a major characteristic of the IDI chamber?

IDIs are capable of a faster top engine rpm limit due to a higher degree of _____ to produce more rapid and even mixing of air and fuel.

Technician A says a power stroke in a modern diesel engine uses only a single injection of fuel. Technician B says late-model diesel engines use multiple injection events during a combustion cycle. Who is correct?

Which one of the following conditions will be produced by prolonged ignition delay in a diesel engine?

Technician A says that a knocking sound in a diesel is normal and is caused by a sharp rise in cylinder pressure. Technician B says that a knocking sound in a diesel is caused by ignition delay of fuel. Who is correct?

Technician A says that without adequate turbulence, air and fuel will not mix, resulting in lost performance and efficiency and in increased emissions. Technician B says that the semi-toroidal shape of the DI chamber is designed to mix the air and fuel. Who is right?

Technician A says the evaporation of diesel fuel from the tank of a diesel bus on a warm day produces more emissions than a car. Technician B says that diesel fuel does not produce a significant amount of emissions due to fuel evaporation. Who is correct?

Inspiration for the engine concept may have occurred when Rudolf Diesel observed a demonstration of a device used to:

Which diesel engine combustion chamber design will produce the fastest coolant warm-up times?

Technician A says that high horsepower (kilowatts) is the most important attribute that an engine needs to pull heavy loads and accelerate quickly. Technician B says that high torque output is the most important attribute that an engine needs to quickly climb hills. Who is correct?

Technician A says that diesel engines can produce more power because air and fuel are not mixed during the intake stroke. Technician B says that diesel engines produce more power because they use excess air to burn fuel. Who is correct?

Technician A says that technological developments now enable the injection of gasoline directly into the combustion chamber of spark-ignited gasoline engines. Technician B says that gasoline direct-injection (GDI) engines inject gasoline near the beginning of the compression stroke. Who is right?