Engine Cooling and Power Boosting

a. Engine cooling system

System used to maintain the optimum

temperature of the engine low enough so it does not

reach the melting point of metals.

a. Engine cooling system

b. Engine air-intake system

c. Engine air-exhaust system

d. None of the above

d. All of the above

Which of the following is a result when the cooling

system of an engine fails?

a. Oil at the engine will oxidize.

b. Distortion of engine metal parts.

c. Piston will difficult to function.

d. All of the above

e. None of the above

b. 30%

During cooling, the percentage amount of heat

needed to be removed from the engine is ____.

a. 10%

b. 30%

c. 70%

d. All of the above

c. Oil cooling

Which is not a type of engine cooling system?

a. Air cooling

b. Water cooling

c. Oil cooling

d. None of the above

b. reduce

Too much removal of heat during cooling will ____

the thermal efficiency of the engine.

a. increase

b. reduce

c. not change

d. None of the above

b. temperature

Cooling of engine is slow during the starting in

order for the engine to reach its operating ____ in a

short time.

a. pressure

b. temperature

c. speed

d. None of the above

a. Air cooling

This reduces the temperature of the engine by means

of a stream of air only from the surroundings.

a. Air cooling

b. Water cooling

c. Water and air cooling

d. None of the above

b. increase the contact area for cooling

Heat transfer fins are provided at the cylinder block

and cover of the engine to ____.

a. strengthen the machine part to be cooled

b. increase the contact area for cooling

c. increase the weight of the engine

d. All of he above

b. Fan

This is provided for stationary air- cooled engines to

effect on cooling.

a. Pump

b. Fan

c. Fins

d. All of the above

d. All of the above

Which of the following is the factor that determine

the amount of heat during air cooling of engine?

a. Area of fin surfaces

b. Velocity and amount of cooling air

c. Temperature of fins and cooling air

d. All of the above

e. All of the above

Which of the following are the advantages of aircooled

engines?

a. Light in weight

b. Less care and maintenance

c. Cheaper to manufacture

d. No damage from frost cracking of cylinder jackets

or radiator tubes

e. All of the above

f. Two of the above

e. All of the above

Type of water-cooling system for engine.

a. Direct or non-return system

b. Thermo-siphon system

c. Hopper system

d. Pump/Force circulation system

e. All of the above

a. single-cylinder engine

Air cooling are usually adopted for ____.

a. single-cylinder engine

b. four-cylinder engine

c. six-cylinder engine

d. None of the above

b. water cooled

Engines usually equipped with radiator are ____.

a. air cooled

b. water cooled

c. oil cooled

d. None of the above

e. All of the above

Purpose of lubrication engine.

a. To reduce friction.

b. To help in cooling engine.

c. To provide sealing effect between the piston and

cylinder liner.

d. To clean the engine.

e. All of the above

f. Three of the above

b. Radiator

Used to cool down the hot water received from

the engine by using a fan that blows the air through

its fins.

a. Thermostat

b. Radiator

c. Pump

d. All of the above

k. None of the above

Which of the following is not a part of a forcedcirculation

water-cooling system?

a. Water pump

b. Fan

c. Radiator

d. Pressure cup

e. Fan belt

f. Water jacket

g. Thermostat valve

h. Temperature gauge

i. Hose pipe

j. All of the above

k. None of the above

e. All of the above

Which of the following are qualities of good

lubricants?

a. Sufficient viscosity

b. Stable under changing temperatures

c. Keep lubricated parts clean

d. Not corrosive

e. All of the above

f. Two of the above

i. All of the above

Engine part that requires lubrication.

a. Cylinder wall

b. Piston and piston pins

c. Crankshaft

d. Connecting rod bearings

e. Camshaft bearings

f. Valves and valve operating mechanism

g. Cooling fans

h. Water pump

i. All of the above

j. Four of the above

c. Oil filter

Used to remove dirty elements in the oil in an

effective way which is made of cloth, paper, felts, and

wire screen.

a. Air filter

b. Gas filter

c. Oil filter

d. None of the above

b. Crankcase breather

Used to prevent building up of pressure in the

crankcase of the engine.

a. Relief valve

b. Crankcase breather

c. Oil pressure gauge

d. None of the above

d. All of the above

Common lubrication systems in multiple-cylinder

engines like in tractors.

a. Splash system

b. Forced-feed system

c. Combination of splash and forced-feed system

d. All of the above

e. Two of the above

c. Coolant

A fluid that circulates through a cooling system of

water-cooled engine to absorb excess heat preventing

it from overheating and maintaining an optimal

operating temperature.

a. Oil

b. Lubricant

c. Coolant

d. None of the above

d. All of the above

Purpose of providing coolant to engine.

a. Prevent freezing of cooling fluid during cold

temperature

b. Protects internal engine parts from corrosion

c. Protect internal parts of the engine from rust

d. All of the above

e. All of the above

Functions of coolant.

a. Absorbs heat

b. Lowers the freezing point of fluid

c. Increases the boiling point of fluid

d. Lubricates and protects corrosion

e. All of the above

b. glycol-based fluid

A coolant is a ____.

a. colored water

b. glycol-based fluid

c. diluted hydroxide

d. None of the above

f. All of the above

What are the key components of engine cooling

system?

a. Coolant

b. Water pump

c. Radiator

d. Thermostat

e. Cooling fan

f. All of the above

c. Thermostat

Which of the following regulates the flow of

coolant ensuring the flow of proper temperature?

a. Radiator

b. Water pump

c. Thermostat

d. Cooling fan

e. None of the above

Coolant

a specialized fluid that absorbs engine

heat and dissipates it through the radiator

Green

[color of coolant]

Frequent replacement is

needed

Blue

[color of coolant]

Commonly used coolant

Red/Pink

[color of coolant]

Often have a an extended life

and to protect aluminum

radiators

Orange/Yellow

[color of coolant]

Frequently used as an

extended life or universal

coolant

c. Hybrid Acid technology

Types of coolant

a. Inorganic additive technology

b. Organic Acid technology

c. Hybrid Acid technology

d. All of the above

a. Inorganic additive technology

Type of coolant that provide quick but sacrificial

form of corrosion protection with typically green

color.

a. Inorganic additive technology

b. Organic Acid technology

c. Hybrid Acid tech

b. Organic Acid technology

Type of coolant that offers longer-lasting or

"extended life protection with often color of red,

orange, yellow or purple.

a. Inorganic additive technology

b. Organic Acid technology

c. Hybrid Acid technology

d. All of the above

b. significantly reduce

It is recommended not to mix different types of

coolants, as it can dilute the additives and

__________their effectiveness and protective qualities.

a. instantly destroy

b. significantly reduce

c. significantly improve

d. None of the above

Carburetion

the process of mixing fuel with air in the correct proportion before sending it to the engine cylinder for combustion

Basic parts of carburetor (6)

float chamber

venturi tube

main fuel jet

throttle valve

choke valve

idle and progression circuits

float chamber

maintains constant fuel level

venturi tube

a narrow throat where air velocity increases, creating suction to draw fuel

main fuel jet

sprays fuel into the venturi

throttle valve

regulates the amount of mixture entering the engine (controls speed and power)

choke valve

enriches mixture during cold starting by restricting air flow

air; air-fuel mixtures

choke valve regulates ___ entering carburtor

throttle valve regulates _____ entering the engine

Idle and progression circuits

supply fuel during low speed operation

powerboosting in engine

forcing more air into the engine cylinder using a mechanically driven compressor

-turbocharging

-supercharging

Turbocharging

uses exhaust gas from the engine to drive the turbine to power the compressor wc forces air into the cylinder

turbocharging

it uses exhaust energy for more efficient power boost

Turbo lag

delay of boost until exhaust pressure builds

- higher exhaust temp requires good cooling and lubrication

Supercharging

uses a mechanically driven compressor connected to crankshaft via belt/ gear to force air into the cylinder

Parasitic loss

consumes engine power to run the compressor

hot spots

uneven cooling may result to ___ ___

principle of liquid cooling

heat flows from engine metal -> coolant -> radiator -> air

water + antifreeze and ethylene glycol

coolant used in liquid cooling

coolant

preveents freezing, raises boiling point and resist corrosion

radiator

dissipates heat to air thru fins

water pump

circulates coolant

thermostat

regulates coolant flow, maintains operating temperature

fan

improve airflow through radiator

hoses and jackets

channels for coolant flow

expansion/overflow tank

handles coolant volume changes

principle of air cooling

Heat is conducted from cylinder walls -> cooling fins -> carried away by moving air

characteristic of an ideal lubricant (6)

1. correct viscosity

2. hi lubricating quality

3. chemical stability

4. corrosion resistance

5. detergency and dispersancy

6. cooling ability

correct viscosity

not too thick (causing drag)

not too thin (causing insufficient lubrication)

high lubricating quality

aintains film under pressure and temperature

chemical stability

resists oxidation and breakdown at high temperature

corrosion resistance

prevents rusting of engine parts

detergency and dispersancy

keeps dirt and carbon suspended, avoiding deposits

cooling ability

removes some heat from friction zones

viscosity

the resistance of a fluid to flow

the thickness of the oil

thick ol

high viscosity

better sealing and film strength, but causes more drag

(hard to pump at cold start)

thin oil

low viscosity

flows easily, reduces drag , but may fail to protect at high temperature

decreases; thinner

viscosity ____ with temperature

(oil gets ___ when hot )

[increases/decreases]

[thicker/thinner]

Society of Automotive Engineers

SAE stands for

SAE classification of oil

0W ->> 25W

thinner ->> thicker

winter

'W' in SAE oils stands for

SAE 30, SAE 40

single -grade oils

single-grade oils

suitable only in limited temperatureranges

SAE 10W-30

SAE 20W-50

multi grade oils

Multi-grade oils

contains additives that allow good performance in bothcold and hot conditions

SAE 10W-30

"10W" -> oil flows like SAE 10 at winter (W) temp -> easy cold start

"30" -> oil behaves like 30 at engine operating temp

SAE 30 or SAE 40

common SAE oil in the Philippines