Deck 2: Introduction to Diesel Engines

Question 1

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?

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

Answer 1

B

Question 2

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

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

Answer 2

C

Question 3

Technician A says that a diesel engine's higher compression ratio helps it to produce more power and use less fuel. Technician B says that higher compression ratios only help the diesel engine produce more torque. Who is correct?

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

Answer 3

A

Question 4

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?

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

Question 5

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?

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

Question 6

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?

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

Question 7

At which of the following compression ratios does the efficiency of an engine begin to diminish with increasing compression?

A)12:1.
B)16:1.
C)23:1.
D)25:1.

Question 8

How many valves will most likely be used by a centrally located fuel injector?

A)Two valves per cylinder.
B)Three valves per cylinder.
C)Four valves per cylinder.
D)Any number of valves.

Question 9

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

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

Question 10

Which combustion chamber design produces the best fuel economy in a diesel engine?

A)Direct injection.
B)Indirect injection.
C)Swirl chamber.
D)Wedge chamber.

Question 11

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

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 12

Which type of fuel nozzle is used in a direct-injection combustion chamber?

A)Multi-orifice nozzle.
B)Pintle-type nozzle.
C)Closed nozzle.
D)Open nozzle.

Question 13

Technician A says that diesel engines inject fuel into the cylinder during the intake stroke. Technician B says that diesel engines inject fuel into the cylinder near the end of the compression stroke. Who is correct?

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

Question 14

Technician A says that diesel engines supply only enough air to completely burn all the fuel in the combustion chamber. Technician B says that diesel engines supply excess air to the combustion chamber to completely burn all the fuel in the combustion chamber. Who is correct?

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

Question 15

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?

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

Question 16

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?

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

Question 17

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?

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

Question 18

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

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

Question 19

Which of the following diesel engine combustion chambers requires a glow plug to start?

A)Direct injection.
B)Indirect injection.
C)Hemispheric chamber.
D)Turbulence chamber.

Question 20

Which combustion chamber design has traditionally operated with the least amount of noise?

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

Question 21

After which 20^th Century event did the thriftier diesel become regarded as a potential replacement for gasoline engines?

A)1970: oil crisis in North America"
B)1960s: creation of OPEC"
C)1930s: development of compact fuel-injection equipment
D)2008: financial crisis in North America"

Question 22

When did Rudolph Diesel (1858-1913) patent his engine?

A)1899"
B)1892"
C)1900
D)1883"

Question 23

Technician A says that diesel engines inject liquid fuel under high pressure into the combustion chamber near the end of the intake stroke. Technician B says that air that is heated during the compression stroke becomes the ignition source. Who is right?

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

Question 24

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

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

Question 25

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

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

Question 26

At what level of efficiency did Rudolf Diesel's slow-rotating engine operate?

A)25%"
B)50%"
C)75%
D)100%"

Question 27

In 1929, Clessie Cummins, founder of Cummins Engine Company, built North America's first diesel-powered:

A)car"
B)truck"
C)boat
D)tractor"

Question 28

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

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

Question 29

Typically, diesel engines will achieve between _____ better fuel economy in comparison to similar gasoline engines.

A)15% and 40%"
B)25% and 70%"
C)25% and 60%
D)45% and 90%"

Question 30

The diesel engine produces significantly higher _______ compared to similarly displaced gasoline-fueled engines.

A)horsepower"
B)torque"
C)emissions
D)speed"

Question 31

In comparison to electric vehicles, a recent study by Energy and Environment Study Institute determined the battery electric models offered for sale in the US have an average base price of $63,000 and an average driving range of:

A)111 miles"
B)211 miles"
C)311 miles
D)411 miles"

Question 32

What are the CO₂ emissions for a diesel engine?

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 33

Technician A says that some studies suggest that electric vehicles may in fact be dirtier than diesel engines due to battery manufacturing. Technician B says that after including emissions from lithium-ion battery, electric vehicles generate half the emissions of a traditional internal combustion engine. Who is right?

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

Question 34

Technician A says that a diesel engine's higher compression ratio helps it to produce more power and use less fuel. Technician B says that higher compression ratios only help the diesel engine produce more torque. Who is correct?

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

Question 35

Until the development of antiknock additives for gasoline, such as tetraethyl lead in the late 1920s, compression of an air and fuel mixture was limited to the ratio:

A)4:1"
B)5:1"
C)6:1
D)10:1"

Question 36

While diesel engines do not have compression limits to combustion, compression ratios above what ratio provide minimal power increases?

A)12:1"
B)14:1"
C)15:1
D)16:1"

Question 37

Engine efficiency drops after a compression ratio of:

A)21:1"
B)23:1"
C)25:1
D)27:1"

Question 38

Compression pressures produce an average pre-ignition temperature of:

A)1,000°F
B)2000°F"
C)3,000°F
D)4000°F"

Question 39

Which of the following is NOT provided by a higher compression ratio?

A)Higher expansion ratios"
B)Improved combustion"
C)Better air-fuel mixture
D)Lower expansion ratios"

Question 40

Smaller four-stroke diesels require a minimum cranking speed of ______ rpm to start.

A)150"
B)180"
C)125
D)135"

Question 41

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?

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

Question 42

There are _____ basic combustion chamber diesel engine designs but numerous variations on both.

A)1"
B)2"
C)3
D)4"

Question 43

Which one of the following is NOT a reason for the IDI chamber being the most popular design in automotive applications in the early 1990s?

A)High-speed capabilities"
B)Favorable emissions characteristics"
C)Inexpensive fuel-injection systems
D)10-15% greater fuel efficiency"

Question 44

DI chambers generally require no:

A)EGR valves"
B)particulate filters"
C)oxidation catalysts
D)starting aids"

Question 45

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?

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

Question 46

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

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

Question 47

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

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 48

Technician A says that diesel engines supply only enough air to completely burn all the fuel in the combustion chamber. Technician B says that diesel engines supply excess air to the combustion chamber to completely burn all the fuel in the combustion chamber. Who is correct?

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

Question 49

Identify the points on the PV (pressure volume) graph between which uncontrolled burn period occurs.

A)A and B"
B)B and C"
C)C and D
D)D and E"

Question 50

Technician A says that injection quantities of fuel in a diesel engine at idle are very large. Technician B says that the cooling effect of excess air and prolonged idle has detrimental effects on the engine. Who is right?

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

Question 51

Technician A says that small quantities of diesel fuel are adequate to create enough cylinder pressure to rotate the crankshaft but produce very little heat. Technician B says that less air in diesels dilutes the heat of combustion and lowers average cylinder temperatures. Who is right?

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

Question 52

Which of these causes more heat retention by the engine around the exhaust ports, thus transferring more heat to the cooling system?

A)Exhaust backpressure"
B)Lower temperature thermostat"
C)Higher temperature thermostat
D)EGR valve"

Question 53

What creates low exhaust temperatures and low cylinder temperatures, which have adverse consequences on engine life and operation?

A)High thermostat"
B)Excess air"
C)Excess fuel
D)Exhaust backpressure"

Question 54

Two technicians are discussing combustion slobber. Technician A says that low piston temperatures also mean the piston has not fully expanded and will easily allow lube oil into the combustion chamber. Technician B says that the black gooey liquid that leaks from exhaust manifold joints and the exhaust pipes when engines are excessively idled is called sludge. Who is right?

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

Question 55

The IDI combustion system uses fuel injected into a smaller, spherical, highly turbulent chamber that is connected to a main chamber through a narrow passageway called a(n):

A)venturi"
B)orifice"
C)nozzle
D)port"

Question 56

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

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 57

What happens to the coarse fuel droplets when fuel initially contacts the incandescent glow plug during start-up and then on the hot walls of the pre-chamber during regular operation?

A)They vaporize"
B)They atomize"
C)They get mixed
D)They boil"

Question 58

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.

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

Question 59

Once the engine is operational, the controller will cycle the plugs on and off during the ________ period.

A)afterglow"
B)pre-glow"
C)heating
D)warm-up"

Question 60

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

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