Union Test Prep Auto and Shop Information Part 1

What is the engine?

The heart of a car with its pirmary function being ot convert the chemical energy stored in fule into mechanical energy that propels the car.

What type of neeryg is stored in fule?

chemical energy

What type of energy propesl the car>

mechanical energy

What type of combustion eengin is found in cars?

internatl combustion engine

How does an internal combusition engine work?

IT burns fuel inside the eignien in order to produce heat which is then converted into mechanical energy

What is a camshaft?

A mechanical compoentn in an engine that controls the opening adn closing of hte engine’s valves.

Camshaft converts ____ motion into ____ motion.

rotational motin, reciprocating motion

The camshaft coverts rotational motion of the….

engine’s crankshaft

Why does the camshaft open and close the valves?

The valves open and close in order to let Air and fuel IN the engine, and the Exhaust gases OUT of the engine.

How does the camshaft work?

The mechanical component spins and pushes the valves open and closed in the correct sequence while the engine runs.

Why is camshaft timing important?

The valves must open and close at the right time so the engine can:

• Take in air and fuel.

• Release exhaust.

• Run efficiently.

What terms are related to the camshaft?

• timing belt/chain

• overhead valve (OHV) and overhead cam (OHC)

• single and double arrangements

What is a critical comoponet of ht engine’s valve train?

The camshaft

What is the timing belt/chain?

A component that connects the camshaft to the crankshaft

What is the purpose of a timing belt/chain?

To ensure that the valves open adn close at the correct time

What do the terms overhead valve (OHV) and overhead cam (OHC) refer to?

These terms fere to the location ofthe camshaft relative tot he egines cylinder head SDLFNSDJNFDSLFNSLFNL cheick make simplier

What is a OHV?

Overhead valve

What is a OHC?

Overhead cam

What is an overhead valve (OHV) eingine?

The camshaft is in the engine block and uses pushrods to open and close the valves in the cylinder head.

Where is the camshaft located in an OHV engine?

The camshaft is located in the engine block, not in the cylinder head.

What do pushrods do in an OHV engine?

Pushrods transfer the camshaft's movement to the valves, causing the valves to open and close.

How do the parts work together in an OHV engine?

1. Camshaft spins.

2. Pushrods move.

3. Valves open and close.

This lets air and fuel in and exhaust out.

Where is the camshaft located in an overhead cam (OHC) engine?

The camshaft is located in the cylinder head, direly above the valves

How does the camshaft operate the valves in an OHC engine?

The camshaft opens and closes the valves directly, so no pushrods are needed.

How do the parts work together in an OHC engine?

• Camshaft spins.

• Camshaft opens the valves directly.

• Air and fuel enter, and exhaust exits.

What type of eingine is more efficient and prodces mor power?

OHC eingines are more effiencet and prodce more pwoer compared ot OHV engines.

What does singel and double arragements refer to?

They refer to the number of camshafts in an engine.

How man camshafts are in a single overhead cam (SOHC)?

One camshaft hat operates all the valves

How many camshafts are in a double overhead cam (DOHC)?

Two camshafts

What are the functions of the two camshafts in a double overhad cam (DOHC)?

One camshaft is dedicated ot hte intake valves

One camshaft is dedicated to the exhaust valves

What type of engine i s commonly found in hihg-erformance engines?

DOHC engines

Wht component is located in the cylinder head of hte engine?

Combustion chamber

What is the combustion chamber?

A mechancial component in an internal combustion engine where air and fuel burn.

What happens inside the combustion chamber?

The air-fuel mixture ignites (burns), creating heat and pressure.

What does the combustion chamber produce?

It produces heat energy from burning the air-fuel mixture.

What happens to the heat energy produced by the combustion chamber?

The heat energy creates pressure that pushes the piston, which is converted into mechanical energy to move the vehicle.

Waht design plays an important role in determinign engine’s performance and efficeny?

The ombustion chambers design

What is a connecting rod?

A mechanicl compoennt that connects the poiston to the crankshaft.

What does a connectign rod do?

The connecting rod converts the piston's up-and-down motion into the crankshaft's rotating motion, which is used to drive the vechile’s wheels.

What type of motion does a piston have?

A piston has reciprocating motion, meaning it moves back and forth (up and down).

Where is the connecting rod located?

The compoen tis located on teh engine’s bottom end and is subjected to stres and forces durign operation

What is a crankshaft?

A mechanical component that converts the pistons backa dn forth motion into rotary motion

The crankshaft uses rotary motion to….

drive the vehcile’s wheels

Where ist he crankshaft located?

In the eingine block and i connected o the pistions through connectign rods

The cylinder (cylindirlca chamber) converts heat energy into….

mechanicla energy

What does the cylinder do?

It is where the air-fuel mixture is compressed and burned to produce heat energy

What does the cylinder house?

The piston

What does the piston do?

The piston moves up and down to squeeze the air-fuel mixture and turn the energy from burning fuel into mechanical energy that powers the engine.

Can engine have mulitple cylindesr?

Yes

What is the cylinder head?

A component that sits on top of a cylinder and seals the combustion chamber

What does the cylinder head contain?

IT contains the intake and exhaust valves, as well as the spark plug and fuel injector.

What is the role of a cylinder head?

To control the flow of air and fule intot he eingine adn exhaust gases out of the engine.

What is mulit-valve culinder head?

a type of culinde had that has more than two vlaves per cylinder.

a standard cylinde rhead has how many intake and ehaust valves per cylinder?

One intake adn one exhust valve per cylinder

A multi-valve cylinder head has how many valves per cylinder?

Three, four, or more valves per cylinder, depending on the engine’s design

What is the eingine block?

The main structural compoent that hiuses the cylinders, pistons, and other components.

What materials are engine blocks usually made from?

Cast iron or aluminum

What does the engine block do?

It supports the weight of the engine and provides a mounting point for engine components

What passages are found inside the engine block?

The eingine block citains passages for Coolant → removes heat , Oil → lubricates moving parts 🛢, and other Other fluids

Why can the engine block handle combustion?

It is designed to withstand high pressure and high temperatures created during combustion.

What is the exhaust valve?

A mechanical compoent that allowss ehuast gase to exist the eingine’s combustion chamber.

Wher is the exhaust and intake valve located and what operates it?

It is located in the cylinder head and is poperated by the camshaft

What is an intake valve?

A mechanical component that allows the air-fuel mixture to enter teh engine’s combustion chamber.

What are pistons responsible for?

they are responsible for compressing the air-fuel mixture and extracting mechanical energy from the combustion process.

What are piston rings?

small metal rings that fit into grooves on the piston’s outer surface.

What is the main job of piston rings?

To create a seal between the piston and cylinder wall to prevent gases and air-fuel mixture from leaking.

What do piston rings prevent from escaping?

they prevent Air-fuel mixture and Combustion gases from leaking past the piston.

Wha do poston rings regulate?

They regulate the amoun of oil that enters teh combustion chamber to lubricate the walls

Why are piston rings important?

they Maintaining a seal, Reduce friction, Prevent wear and tear

What are wrist pins?

small, cylindrical components that connect the piston to the connecting rod

What are wrist pins made of and what are they responsible for>

They are made of steel/high-strength materials, adn are resonsiblef for transfering the piston's up-and-down motion so the crankshaft can rotate and produce mechanical energy.

What is the four-stroke cycle in an internal combustion engine?

A process that converts fuel into mechanical energy to power a vehicle.

What is a “stroke” ?

The movement of the engine’s piston inside the cylinder during each phase of the cycle.

What are the two types of strokes?

upward (also called compression stroke) and downward (expansion or power stroke).

What are the four stages in teh four-stroke cycle in order?

1) intake

2) compression

3) combustion

4) exhaust

Each of the four stages in the cycle—intake, compression, combustion, and exhaust—corresponds to how many strokes?

One stroke (either upward or downward) of the piston.

WWhat happens durign the intake stage in a four-stroke cycle?

The piston moves down, creating suction that pulls air and fuel into the cylinder through the intake valve.

What happens during the compression stage in a four-stoke cycle?

The piston moves back up and squeezes (compresses) the air-fuel mixture, making it ready to burn.

what happens durign teh combustion stage ina four-stroke cucle?

When teh piston reaches the top, the spark plug ignites the compressed air-fuel mixture, forcing the piston down and turning the crankshaft to create mechanical energy.

What happens during the exhaust stgae in a four stroke cycle?

The piston moves back up and pushes the burned gases out of the cylinder through the exhaust valve, clearing the cylinder for new air and fuel.

The four-stroke cucle turns ____ energy from fthe fuel into ____ energy t o power the engine

chemical, mechanical

What are the common cylinder arragements in internal combustion engines?

• Inline

• V

• Flat

• Radial

What is an inline (straight) engine?

All cylindesr are arranged in a staight line along the same plane, one after the other. The configuration is compact and well ballanced

When are inline (straight) eingines sued for?

They are ued for engiens with a smaller number of cylinders, typically three, four, or isix

What is a V engine?

The cylinders are arranged in two seperate banks, forming a “v” hsape when viewed from teh end.

When are V engines used for?

Used for larger numbers of cylinders such as six, eight, 10, or 12. Therefore, makin the engine popular for high-performance and larger vehciles.

What is a flat (bboxer) engine?

The cylinders are arranged horizontally in two opposing banks, with the pistons moving towards and away from each other.

What deso th flat (boxer) engine offer?

IT offersa low center of gravity and smooth operation, yet is more complex and takes up more width space.

Flat (boxer) engines are most commonl used for?

Subaru and porshce vechiels with temsot common configuratio being flat-4 and flat-6.

What is a radiail engine?

The cylinder are arrange in a circle around acentral crankshaft with each piston connecting directly to the crankshaft.

What is a radial engine used for?

It is used in earlt aircraft engines due to the high power-to weight ratio and compact size. Yet, radial egnesar eless common in modern automotive applications.