Brainscape's Knowledge GenomeTM

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


See full index

Diesel Mechanics/Heavy Truck Maintenance Program > Intro: Diesel Truck Mechanics > Flashcards

Intro: Diesel Truck Mechanics Flashcards

1
Q

Diesel Engine vs Gas Fueled Engines

A

Both Internal Combustion Engines.

Diesel engine has more hauling power, longer engine life, and much better fuel economy, operate at higher compression ratios, & the method of supplying & igniting the fuel makes it more efficient, also the grade and type of fuel diesel engines use makes it more efficient

Gasoline engine delivers usable torque through a much wider rpm range, runs quieter, & offers faster acceleration

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

ATA

A

American Trucking Association

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

ASE

A

Automotive Service Excellence

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

What are the 8 operating systems of a diesel powered vehicle?

A

Engine
Brake System
Suspension & Steering
Transmission
Driveline
Electrical & Electronic Systems
Heating & Air Conditioning
Tires & Wheels

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

Why is the engine important?

A

It is the Power Source of the vehicle. It is needed for all other components to function.

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

What brake system is used in midsized trucks and which system is used in large freight hauling trucks?

A

Hydraulic Brake System is used for midsized trucks.

Pneumatic Brake System is used for very heavy vehicles.

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

Explain how the Hydraulic Brake System Works:

A

The Hydraulic Brake System
supplies pressurized hydraulic fluid
to pistons
at each wheel
causing the brake pad
to rub against
the rotating disk

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

How is the hydraulic fluid pressurized?

A

By an engine driven pump

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

Between a hydraulic brake system and a pneumatic brake system, which one is more powerful?

A

Pneumatic Brake System

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

Does the Pneumatic Brake System control the truck or trailer brakes?

A

It controls Both!

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
11
Q

How does the Pneumatic Brake System work?

How is PBS controlled?

A

The Drive System uses engine power to turn on the Air Compressor which then raises the Air Pressure which is then supplied to the Pneumatic Brake System & other components.

Pressurized Air.

It forces the pad against the rotating disk.

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
12
Q

ABS

A

Antinlock Braking System

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
13
Q

What vehicles are equipped with ABS?

A

Most diesel vehicles built after 1996

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

How is ABS controlled?

A

Electronically

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

Term: PBS

Term: HBS

A

Pneumatic Brake System

Hydraulic Brake System

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
16
Q

What does ABS do?

A

Prevents wheels from locking up during sudden stops

Electronically monitors each individual wheel speed

Momentarily relieves braking force on any wheel that shows signs of locking up

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

What does the suspension and steering system do?

A

These systems allow the driver to properly control the vehicle on the road

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

Hydraulic

A

Pressurized Liquid

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

Pneumatic

A

Pressurized Air

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

What does the suspension system do?

A

Keeps the tires in contact with the road and prevents disturbance to passengers by absorbing road bumps.

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

What various load carrying & absorbing components does the suspension system incorporate?

A

Leaf spring, shock absorbers, rubber cushions, & air filled pneumatic components.

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

What does the steering system do?

A

Allows driver to control the direction of the vehicle.

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

What does the power steering system do?

A

It is a system powered by either a hydraulic or pneumatic system that makes it easier to steer vehicles.

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

What does the power steering system rely on to adjust the amount of power assistance needed?

A

Hydraulic valves or electronic control

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
25
Q

Components of Automatic Transmission

A

No driver input

Hydraulic and electronic control systems determines when to shift gears and which gears to select

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
26
Q

What is a Torque Converter?

A

A device that transmits power from the engine to an automatic transmission

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
27
Q

What does the transmission system do?

A

Helps vehicle change speeds (imagine bike gears)

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
28
Q

Standard Transmission

A

A.K.A manual; stick shift

4-20 gear selections

Relies on clutch to control the transfer of power from engine to transmission

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
29
Q

What are the steps to using standard transmission ?

A
  1. Driver must disengage transfer of power from engine to the transmission by depressing a clutch pedal with their foot.
  2. Manually move gearshift lever to change transmissions internal gearing combination
  3. Restore power transfer connection been engine and transmission
How well did you know this?
1
Not at all
2
3
4
5
Perfectly
30
Q

What does the driveline system do and what components do it include?

A

Connect the engine to the wheels

Main transmission (sometimes), auxiliary power transmission, the difffrrentials, drive axes, & drive shafts

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
31
Q

Tandem Drive System

A

Systems with 2 sets of rear drive wheels

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
32
Q

Rear Wheel Drive

A

Most med sized and all large trucks

Rear wheels carry much of the weight

Larger, stronger, than FWD

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
33
Q

FWD

A

Midsized & Comoact Vehicles

Engine & transmission is located at front over wheels

Uses this weight to provide better attraction for the front

34
Q

AWD

A

A.K.A. 4WD

Better traction than RWD & FWD

Often used off-road

Light trucks, utility vehicles, heavy construction trucks, military veh

35
Q

Differentials

A

Change direction of transmissions power input so it can be directly applied to rotating the drive wheels

36
Q

Drive Axels

A

Directly turns the wheels

37
Q

Drive Shafts

A

Transfers power from 1 driveline device to the next

38
Q

Examples of Electrical and Electronic Systems

A

Battery, battery charging system, truck and trailer lighting circuits, starter system, windshield wiper, horn, radio, and other accessory circuits circuits, engine control system’s, ABS system, climate control system, pneumatic power circuit

39
Q

What is Direct Current and where is it used?

A

Constant Source of Electrical Voltage

Same type of current that’s used to power cordless appliances or used on devices that run on batteries

40
Q

How does vehicles optical systems operate?

A

All vehicles electrical systems operate on a direct current provided by the vehicle’s battery Through an array of harnesses

41
Q

A _________ recharges the battery as tye engine is running

A

Separate electrical system

42
Q

Heat is produced by _____

A

The running engine

43
Q

Heating systems are used to do what?

A

Heating systems are used to keep a shut down engine warm when outside air temperatures are cold

44
Q

Why are engines difficult to start in cold weather?

A

Because fuel in a diesel engine is ignited when it comes in contact with hot air

45
Q

What system are the tires and wheels a part of

A

They are sometimes considered to be a part of the suspension system but they are considered to be a system all of their own

46
Q

Internal conbustion engine means that

A

Fuel is burned inside the engine to produce power/mechanical energy

47
Q

External conbustion engine means that

A

Fuel is burned outside of the engine

Ex: Steam engine/boiler burns fuel to produce steam and the steam is sent to the engine to produce power

48
Q

Intake Stage

A

Air is pressurized and supplied outside of the cylinder by a Turbocharger and then forced into the cylinder where it is further pressurized

49
Q

Compression Stage

A

Both intake and exhaust valve are closed

Piston rises and compresses air mixture that’s trapped in the combustion chamber

Due to compression the temp is then increased and as the piston reaches BDT C diesel fuel is injected through a nozzle

50
Q

Power Stage

A

Measured fuel is sprayed into the hot air of the cylinder, igniting it, creating a combustion, which then presses the piston back down.

This motion is then transferred to the rod and crankshaft

51
Q

Exhaust Stage

A

Stage #4

The burned exhaust gasses are released from the cylinder

Stage one starts again

52
Q

What is one engine cycle?
How many cycles are completed per minute?

A

A complete run through of all 4 stages.

A typical crank shaft will complete 500 to 2100 revolutions every minute

53
Q

What is the definition of pressure?

A

Pressure is the measure of how hard the contained air presses against the surface of the container in which it’s held.

54
Q

What is a piston stroke?

A

A total distance that piston moves from the top of the cylinder to the bottom

55
Q

What are the differences between a 2 stroke engine and a 4 stroke engine

A

4 stroke engine
1.Intake
2.compression
3. power
4. exhaust

Modern diesel engine trucks

Two stroke engine
1.Intake/compression
2.power/exhaust

Produces more power; found in older buses etc; not as fuel efficient; produces more pollution

56
Q

How many valves and ports does a 4 stroke engine contain?

A

Contains 2 mechanical valves & 2 ports (exhaust & intake)

It also contains an injection nozzle & injection pump.

57
Q

Injection Pump

A

Delivers correct amount of sufficiently pusherized fuel to the nozzle

58
Q

Injector Nozzle

A

Engine part that introduces fuel into the chamber

59
Q

What happens when the temperature is below 40ﾟ outside?

A

The cylinder temperature is unable to make the fuel even after compression so starting the fluid which is easier to ignite is introduced to the cylinder to begin the process in the read the temperature

In smaller vehicles a glow plug plug (small electronically powered heater) heats the air in the compression chamber prior to starting

60
Q

A diesel engine’s _____________ system allows it to deliver as much power as possible while consuming as little fuel as possible

A

Computer control

61
Q

The small space above the piston in which fuel is burned is called the ___________

A

Combustion chamber

62
Q

When going uphill or downhill which gears are correct?

A

Uphill = Lower Gear
Downhill = Higher Gear

63
Q

A heavy duty vehicles electrical system is normally rated at how many volts?

A

12 or 24 volts

64
Q

What’s an example of a freight transporting diesel powered vehicle?

A

Train

65
Q

What joins the tractor and the trailer?

A

The 5th wheel

66
Q

Chassis Dynamometer

A

Evaluates engines overall performance while still installed in the vehicle.

67
Q

What is a diesel engine?

A

An internal combustion engine that uses compression hear to ignite a fuel charge

68
Q

In a diesel engine what is not mixed before entering the combustion chamber?

A

Fuel and air

69
Q

In a diesel engine how is speed controlled?

A

By regulating the amount of fuel air mixture delivered to the cylinder.

70
Q

What is the function of the governor in a diesel engine?

A

A governor is a device that senses engine speed and loads/changes fuel delivery accordingly.

No longer used.

71
Q

Diesel fuel contains more _________ than gasoline

A

Heat energy (joules)

72
Q

What problems are associated with diesel fuel at low temps?

A

Fuel starvation & Nonstart conditions

At lower temps the the wax begins to solidify into crystals which can block the fuel flow

73
Q

Who was the 1st engineer to develop a compact reliable diesel fuel injection pump?

A

Robert Bosch

74
Q

Compression Ratio

A

Comparison of the volume of air in a cylinder before compression with its volume after compression

Typical compression ratios used in a diesel engine range btwn 15:1 to 24:1

75
Q

Diesel engine fuel is ignored simply by the ____

A

Heat generated from compression

76
Q

What is the most common fuel system found on modern diesel engines

A

The high pressure common rail fuel injection system

77
Q

2 & 4 stroke gasoline engines
vs
2 & 4 stroke diesel engines

A

All high horsepower gasoline engines are 4 stroke engines. 2 cycle gasoline engines are used for light duty applications such as power tools, lawn equipment, and boat motors.

In contrast

2 and 4 cycle diesel engines can be used in high horse power applications

78
Q

What happens to the diesel fuel if the temperature increases more than a 100ﾟF?

A

The diesel fuel finds out and reduces the power output

79
Q

Some of the technological developments made in the past 30 years include:

A

❏ Enhanced use of turbochargers and superchargers to increase power output and improve efficiency.

❏ Changes in combustion chamber, piston, and valve designs to increase fuel burning efficiency and power output.

❏ Advanced materials used to construct pistons, connecting rods, and other engine components.

Use of charge air coolers resulting in a 3%–5% improvement in fuel mileage and a reduced exhaust emissions.

❏ Improvements to unit fuel injectors and common rail injection systems, which are both capable of attaining higher injection pressures than earlier fuel injection systems.

❏ Matched intake and exhaust flow systems.

❏ Low-flow cooling systems and extended life cool-ants.

❏ Computerized fuel management systems and variable injection timing.

❏ Introduction of ultra-low sulfur diesel fuel and improved engine oil formulations to decrease emissions and improve efficiency.

❏ Incorporation of emission control technologies, such as exhaust gas recirculation systems, oxida-tion catalysts, particulate trap filters, and selective catalytic reduction systems—all designed to lower emissions and meet current environmental regulations

80
Q

Stationary applications for diesel engines include

A

●electronic power generators
●industrial PTO (power takeoff) units
●motorized pumps
●cranes
●power shovels

Diesel Mechanics/Heavy Truck Maintenance Program (2 decks)

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