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Automotive Level 2 > Engines - Cooling Systems and Air Conditioning > Flashcards

Engines - Cooling Systems and Air Conditioning Flashcards

1
Q

Name a component used to improve outside air cooling

A

Cooling fins

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2
Q

Give 2 advantages of air cooling

A

Less engine maintenance
Shorter warm-up period

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3
Q

Where does the air come from in outside air cooling?
Where does the air come from in forced air cooling?

A

Air from outside the car enters to cooling system when the car is moving
Air is blown in by a fan, which still produces airflow when the car is stationary

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4
Q

Where is the oil cooler mounted?
What is its purpose?

A

Mounted completely in the outside air flow
To cool the oil so that it does not lose its lubricating properties

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5
Q

By how many degrees is oil cooled by outside air flow?

A

25 to 50 degrees C

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6
Q

Which kinds of cooling are direct and which are indirect:
Outside air cooling
Forced air cooling
Oil cooling
Liquid cooling

A

Direct
Direct
Indirect
Indirect

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7
Q

List 3 advantages of liquid cooling

A

Engine cools more uniformly
Less engine noise
Engine remains at temperature for longer, so that it can get started more quickly after a pause in driving

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8
Q

List the main 5 components of a liquid cooling system

A

Coolant pump
Thermostat
Fan
Radiator
Pressure cap

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9
Q

What is the function of a thermostat in a liquid cooling system

A

Controls the flow of coolant through the radiator

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10
Q

What is the purpose of the pressure cap in a liquid cooling system?

A

To increase the pressure and therefore increase the boiling point of the coolant

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11
Q

What will dashboard signals inform you about in terms of the coolant?

A

Coolant temperature
Coolant level

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12
Q

What is a thermostat referred to as if it only operates on one valve? What about if it operates on two?

A

A single-action thermostat
A double-action thermostat

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13
Q

How does a thermostat operate?

A

Wax, which expands as it heats up

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14
Q

Where is the pressure cap usually located? What does it do?

A

On the expansion tank or the radiator
Raises the boiling point of coolant

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15
Q

What should you never do with a pressure cap? Why?

A

Take it off while still hot
The water can boil immediately and shoot into your face

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16
Q

What 2 valves can be found inside a pressure cap?

A

Vacuum valve
Relief valve

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17
Q

What do you use an anti-freeze gauge for? How to you use one? (in 4 steps)

A

Determine the freezing point
Open the glass gauge cover
Drop a tiny bit of coolant onto the plate under the over
Press the cover back down
Put it to your eye and look at the reading

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18
Q

In coolant freezes, what components can it cause to crack?

A

Engine block
Cylinder head
Radiator
Coolant hoses

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19
Q

What is the optimum temperature for an engine called?

A

Operating temperature

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20
Q

The engine dissipates its heat through the cylinder wall. Where does this heat go?

A

The coolant

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21
Q

How does the heated coolant transfer its heat to the outside air?

A

Via the radiator

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22
Q

List 3 symptoms of insufficient coolant

A

Overheated engine
Uncontrolled combustion
Poor lubrication

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23
Q

List 3 symptoms of excessive coolant

A

High fuel consumption
Internal engine contamination
Condensation of fuel droplets

24
Q

List 2 functions of the expansion tank

A

Provide coolant when there is a shortage
Store excess coolant

25
Q

Can the expansion tank be connected to the cooling system by systems where the coolant does flow through the expansion tank or systems where it doesn’t flow through the expansion tank?

A

Both

26
Q

What 2 things happen in a cold expansion tank when the temperature rises? What will happen when it lowers back down (other than the reverse of when it goes up)?

A

The excess pressure valve on the pressure cap opens
The coolant flows into the expansion tank
The vacuum valve on the pressure cap opens

27
Q

What is a cooling system referred to as if the coolant does not flow through the expansion tank?
What about when it does?

A

Cooling system with a cold expansion tank
Cooling system with a hot expansion tank

28
Q

What is the main feature of a cold expansion tank that is different to hot, in terms of process

A

The pressure cap always remains closed

29
Q

Where is a hot expansion tank positioned? Why?

A

Above the radiator
So that the radiator is always full of coolant

30
Q

What is the purpose of a radiator?

A

To dissipate heat from the coolant to the outside air

31
Q

What is the radiator core usually made of?
What about the water tanks?

A

Aluminium
Plastic

32
Q

What are the main 2 components of the radiator core mesh?

A

Small pipes
Cooling fins

33
Q

Why do radiator cores have cooling fins?

A

To increase the cooling surface area

34
Q

Name the 2 main types of radiator

A

Crossflow
Downflow

35
Q

Other than the water flowing down, list 2 ways to know if a radiator is downflow

A

The water tanks are on the top and bottom
There is a filler cap

36
Q

Other than the water flowing from right to left or lefft to right, list 2 ways to know if a radiator is crossflow

A

The water tanks are on the left and right
The filler cap is on the expansion tank, no the radiator

37
Q

Why are crossflow radiators used more in modern cars?

A

Smaller height

38
Q

What is the main difference between an electric thermostat and a mechanical one?

A

The electric thermostat has a filament in the wax

39
Q

Give one advantage of using an electric thermostat over a mechanical one

A

Can respond more effectively to different operating situations

40
Q

What happens to refrigerant when it flows through the evaporator?

A

It turns from liquid to gas

41
Q

What happens to refrigerant when it flows through the evaporator and the outside temperature is very low? (3 things)

A

Not all of it turns to gas
A little liquid refrigerant leaves the evaporator
The compressor is fed with liquid refrigerant

42
Q

What happens to refrigerant when it flows through the evaporator and the outside temperature is very high?

A

A little liquid refrigerant leaves the evaporator

43
Q

What happens if a little liquid refrigerant leaves the evaporator and is therefore fed to the compressor?

A

The compressor is damaged, because it cannot compress a liquid

44
Q

What does the accumulator do?

A

Collects the unevaporated liquid refrigerant that otherwise would flow to the compressor and damage it

45
Q

What kind of orifice always lets through the same amount of refrigerant?

A

Fixed orifice

46
Q

What can be used instead of a fixed orifice, which reduces the chance of liquid getting to the compressor?

A

An expansion valve

47
Q

Where in the system would the accumulator be put in comparison to the fixed orifice?
What about the filter dryer in comparison to the expansion valve?

A

After
Before

48
Q

List 2 components which are specific to a non-regulated air conditioning system

A

Accumulator
Fixed orifice

49
Q

List 2 components which are specific to a controlled air conditioning system

A

Filter dryer
Expansion valve

50
Q

Where is the condenser located? Why?

A

In the front centre of the engine compartment
To maximise airflow through it

51
Q

Where are the evaporator and expansion valve located?

A

In the back of the engine compartment, behind the bulkhead

52
Q

What is the bulkhead?

A

The panel that separates the engine compartment from the passenger compartment of a vehicle

53
Q

How does an internal combustion engine drive the air conditioning?

A

Using a belt

54
Q

List the 4 main components of the air conditioning system

A

The evaporator
The valve (can be an expansion valve or fixed orifice)
The compressor
The condenser

55
Q

Which of the 4 main component of the air conditioning system does the refrigerant flow through?

A

All of them

56
Q

What 2 things happen to the refrigerant when the temperature drops?

A

The pressure of the refrigerant remains the same
The temperature of the refrigerant drops

57
Q

In what state is the refrigerant when it leaves the condenser?

A

Liquid

Automotive Level 2 (20 decks)

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