ELEC 3

Question 1

is a machine that converts chemical energy of
fossil fuels into mechanical energy through combustion

Answer 1

internal combustion engine (ICE)

Question 2

is an internal combustion engine in which the piston completes
four separate strokes while turning the crankshaft. It is commonly used in outdoor power
equipment and vehicles.

Answer 2

Four stroke Engine

Question 2

is an engine that completes a power cycle with two strokes of the
piston during only one crankshaft revolution.

Answer 2

Two-stroke Engine

Question 2

The intake valve is open, and fuel is drawn in with a downward stroke.

Answer 2

Intake:

Question 3

As the piston moves upward, the fuel is compressed.

Answer 3

Compression:

Question 4

After the fuel is compressed, it is ignited to produce the engine’s power.

Answer 4

Power:

Question 5

The exhaust valve opens, and the exhaust gases exit the cylinder.

Answer 5

Exhaust:

Question 6

engine, air mixes with the fuel, which is then compressed by pistons and
ignited by the sparks from spark plugs.

Answer 6

Gasoline

Question 7

it uses a series of small explosions (combustions) to power the
vehicle. In a diesel engine, the air is compressed followed by fuel being injected into the
cylinder. Because the air is so hot, the fuel ignites without the use of a spark plug as in the
case of a gasoline engine.

Answer 7

Diesel

Question 8

Using this procedure, the lubricating oil is positioned in the sump or through at the
bottom of the crankcase. On the wide end of the connecting rod are scoops, which resemble
spoons. The oil sump supplies this pan with oil, either by gravity or with a gear pump. The
provided dipper is located at the connecting rod’s bottom end. The dipper descends into the
oil trough after splattering oil out of the pan. A fog or mist of oil that drains the engine’s
internal components, including the cylinder walls, pistons, bearings, timing gears, piston pins,
etc., is maintained by the splashing action of oil. The splash oil falls into the sump instead

Answer 8

Splash Lubrication System

Question 9

Its function is to move the oil and force it through the oil passages so it can
flow to the bearings and upper valve train.

Answer 9

Oil Pump

Question 10

This system delivers the oil directly to the motor’s crankshaft and timing camshaft via
the proper oil pathways. The connecting rod, piston pin, and oil gears then arrive in the main
gallery first. This could be a channel or pipe made of iron, and it passes through holes in each
of the main bearings. through drilled holes in the crankshaft, bearings, and connecting rod
from the primary wide end bearings. There, the rings, pistons, and walls are lubricated. A
positive displacement pump, usually shaped like a gear or vane, is used for lubricating timing

gears in a separate location. Additionally, an oil galler valve stem transports the oil to the
rocker arm shaft. The surplus oil is transferred to the crankcase 1 cylinder head.

Answer 10

Forced feed Lubrication System

Question 11

It is a container mounted at the bottom of the cylinder block with gaskets to
prevent leakage. Its purpose is to store a certain amount of oil and maintain a constant
oil level suitable for the pump, especially when climbing hills.

Answer 11

Oil Sump

Question 12

The filter prevents the passage of impurities and suspended particles and *
allows clean oil to pass through.

Answer 12

Oil Filter

Question 13

It serves as the passages in an engine lubrication system that deliver oil to
critical components such as the crankshaft bearings, camshafts, and pistons. These
passageways are integrated throughout the engine block and cylinder head and are
typically made of metal.

Answer 13

Oil Galleries

Question 14

It prevents overheating of the oil through the radiator.The coolant passes
through tubes carrying the hot oil, where the coolant transfers the heat and cools it.

Answer 14

Cooler

Question 15

The function of this valve is to regulate the maximum pressure limits of the oil
coming out of the pump, so that the continued pressure does not lead to an explosion
in the lubrication system.

Answer 15

Oil Pressure Relief Valve

Question 15

Typically used for diesel engines with moderate to heavy loads,
these standards offer more robust protection.

Answer 15

SAE 10W-30 or 15W-40:

Question 16

Ideal for hot-running turbocharged diesel or
high-performance gasoline engines.

Answer 16

SAE 5W-40 or 10W-50 (synthetic):

Question 17

Measures the oil’s resistance to flow. The proper grade depends on engine type and
temperature range.

Answer 17

Viscosity:

Question 18

Provides superior fuel economy and cold-start lubrication, making
them perfect for contemporary gasoline engines.

Answer 18

SAE 0W-20 or 5W-30:

Question 18

is one of the most essential safety mechanisms in any vehicle,
responsible for controlling motion, reducing speed, or bringing the vehicle to a complete stop
through the conversion of kinetic energy into heat energy.

Answer 18

BRAKE SYSTEM

Question 19

are among the earliest forms of braking systems, primarily used in
bicycles, motorcycles, and early automobiles. In this system, braking force is transmitted
through a series of mechanical linkages such as cables, rods, and levers. When the driver
presses the brake pedal, the force is directly transferred to the brake shoes or pads to create
friction against the drum or disc. As described by LearnMech (n.d.), although simple and
cost-effective, mechanical brakes require regular adjustment and maintenance due to wear
and stretch of linkages.

Answer 19

Mechanical Brake System

Question 20

is the most widely used in modern vehicles. Ahmad et al. (2002)
describe it as a closed system filled with incompressible fluid (typically brake fluid) that
transmits pressure uniformly through the brake lines. When the brake pedal is pressed, the
master cylinder converts mechanical force into hydraulic pressure, which then actuates

Answer 20

Hydraulic Brake System

Question 21

Used mostly in heavy commercial vehicles and trucks, the air brake system employs compressed air instead of fluid to transmit pressure. According to Shi (2016), air brakes are more reliable for large vehicles because air can be replenished easily and is unaffected by small leaks. The system typically consists of an air compressor, storage tanks, valves, and brake chambers. When the driver presses the pedal, compressed air enters the brake chamber, pushing the diaphragm to apply the brakes.

Answer 21

3. Air (Pneumatic) Brake System

Question 22

Modern vehicles, especially electric and hybrid cars, often utilize electric or electromagnetic braking systems. These systems use electrical energy to generate a braking force, often integrated with regenerative braking technology, which converts kinetic energy back into electrical energy during deceleration. LearnMech (n.d.) highlights that these systems improve efficiency, reduce wear on mechanical components, and enhance overall energy conservation.

Answer 22

4. Electric and Electromagnetic Braking Systems

Question 23

As Ahmad et al. (2002) note, many modern vehicles adopt dual-circuit hydraulic systems or combination systems (such as disc brakes in the front and drum brakes in the rear). This design improves braking stability, distributes pressure evenly, and ensures safety even if one circuit fails.

Answer 23

5. Combined or Dual Braking Systems

Question 24

is an example of a mechanical assembly that converts mechanical power into hydraulic energy. It basically transfers energy using pressurized fluid, and with this incompressible liquid, it could power an entire industry. The hydraulic system works based on Pascal's Law, which states that when pressure is applied to a confined fluid, that pressure is transmitted equally to all parts of the fluid and the walls of its container. As seen in the image, there are also different parts in a hydraulic system. It includes hydraulic pumps, cylinders, and most especially, motors.

Answer 24

HYDRAULICS

Question 25

is a mechanical assembly that converts thermal energy from pressurized steam into mechanical work that will drive electric generators, which produce electricity. Power generation continues to utilize steam turbines nowadays; however, their service life and operational efficiency, particularly in the context of power generation, continue to be restricted by tribology. Parts such as turbine blades and valve spindles function under extreme temperature and stress conditions under which lubricants fail. Friction, erosion, corrosion, and wear tend to cause costly maintenance and excessive downtime. Therefore, understanding the mechanisms of tribology, surface contact, and lubricant interface to mitigate the associated problems will result in greater turbine operational reliability.

Answer 25

STEAM TURBINES

Question 26

serves as the heart of the braking system. It converts the mechanical force from the brake pedal into hydraulic pressure, which is transmitted through brake lines to the wheel brakes.

Answer 26

master cylinder

Question 27

combines multiple control functions to balance hydraulic pressure between the front and rear brakes, ensuring smooth and safe braking under various conditions. It is internally lubricated by the brake fluid and does not require external lubrication. Regular inspection for corrosion or leaks is important, and the valve should be replaced if it fails to balance pressure properly (Ahmad et al., 2002).

Answer 27

combination valve

Question 28

regulates the flow of brake fluid to the front brakes by slightly delaying their engagement. This ensures that the rear brakes are applied first, creating balanced braking and reducing the risk of the vehicle’s nose diving during light braking. The

Answer 28

metering valve

Question 29

transport brake fluid to each wheel while allowing free movement between the vehicle’s body and its suspension. Though their interiors are filled with brake fluid, the metal connectors or fittings can be lightly coated with

Answer 29

flex lines or flexible hoses

Question 30

acts as a connector that evenly distributes brake fluid between the left and right rear brakes. This ensures equal braking force on both sides of the vehicle for stability. The fitting is internally lubricated by the brake fluid, and its connections should be checked periodically to ensure they remain secure and leak-free (LearnMech, n.d.).

Answer 30

“T” fitting

Question 31

Takes power from the engine and, using gears, delivers it to the driveshaft at the appropriate torque and speed for the current gear.

Answer 31

Transmission:

Question 32

A long tube that connects the transmission to the rest of the drivetrain. It transfers power to the drive wheels.

Answer 32

Driveshaft:

Question 33

Found on driveshafts and axles, these joints allow for more flexibility than U-joints, operating at high angles while maintaining a constant speed.

Answer 33

CV Joint (Constant-Velocity Joint):

Question 33

A flexible pivot point in the driveshaft that allows for the transmission of power at different angles, accommodating suspension movement.

Answer 33

U-joint (Universal Joint):

Question 34

ability to resist decomposition when exposed to temperature changes

Answer 34

THERMAL STABILITY

Question 34

A lubricant's ability to resist chemically combining with oxygen.

Answer 34

Oxidation stability

Question 35

are typically silicone compounds which increase surface tension in order to discourage foam formation.

Answer 35

Anti-foaming agents

Question 35

A lubricant's property that allows it to give lower coefficients of friction than another fluid of the same viscosity.

Answer 35

Oiliness

Question 36

are compounds that prevent crystallization of waxes. Long chain alkylbenzenes adhere to small crystallites of wax, preventing crystal growth.

Answer 36

Pour point depressants

Question 37

are compounds that allow lubricants to remain viscous at higher temperatures. Typical VIIs are polyacrylates and butadiene.

Answer 37

Viscosity index improvers (VIIs)

Question 38

suppress the rate of oxidative degradation of the hydrocarbon molecules within the lubricant. At low temperatures, free radical inhibitors such as hindered phenols are used, e.g. butylated hydroxytoluene. At temperatures >90 °C, where the metals catalyze the oxidation process, dithiophosphates are more useful. In the latter application the additives are called metal deactivators.

Answer 38

Antioxidants

Question 39

ensure the cleanliness of engine components by preventing the formation of deposits on contact surfaces at high temperatures.

Answer 39

Detergents

Question 40

form protective 'tribofilms' on metal parts, suppressing wear. They come in two classes depending on the strength with which they bind to the surface. Popular examples include phosphate esters and zinc dithiophosphates.

Answer 40

Anti-wear additives

Question 40

are usually alkaline materials, such as alkylsulfonate salts, that absorb acids that would corrode metal parts.

Answer 40

Corrosion inhibitors (rust inhibitors)

Question 41

form protective films on sliding metal parts. These agents are often sulfur compounds, such as dithiophosphates.

Answer 41

Extreme pressure (anti-scuffing) additives

Question 42

reduce friction and wear, particularly in the boundary lubrication regime where surfaces come into direct contact.

Answer 42

Friction modifiers

Question 43

For modern gasoline engines; prevents sludge, oxidation, and low-speed pre-ignition.

Answer 43

API SP or SN:

Question 44

For heavy-duty diesel engines; offers high soot control and thermal stability.

Answer 44

API CK-4 or CJ-4: