Engine Fundamentals, Mechanics, and Shop Basics

A comprehensive set of question-and-answer flashcards covering engine fundamentals, mechanical principles, operational systems, and basic shop tools to aid in exam preparation.

What is combustion in an internal combustion engine?

The burning of an air-fuel mixture inside the engine to provide energy.

Where does combustion take place in an internal combustion engine?

Inside the combustion chamber located in the cylinder head.

What is the primary function of the engine block?

To house the cylinders and other internal engine components.

Which component guides the pistons and converts heat energy into mechanical energy?

The cylinders.

Which part connects the piston to the crankshaft?

The connecting rod.

What does the crankshaft do?

Converts the piston's linear motion into rotational motion to power the vehicle.

What is the role of the camshaft?

To open and close the intake and exhaust valves in sync with piston motion.

Which cylinder arrangement is commonly used in smaller engines?

Inline cylinder arrangement.

List the four strokes of a 4-stroke engine cycle in order.

Intake, compression, power, exhaust.

During which stroke is the air-fuel mixture compressed?

The compression stroke.

What event starts the power stroke?

The spark plug ignites the compressed air-fuel mixture.

Why is correct firing order important?

It balances engine operation and minimizes vibrations.

What is a common firing order for a four-cylinder engine?

1-3-4-2.

What does the stoichiometric ratio describe?

The proper air-to-fuel ratio for complete combustion.

What determines when the spark plug fires?

Ignition timing.

What is engine detonation?

An uncontrolled explosion of the air-fuel mixture instead of smooth burning.

What is the purpose of engine coolant?

To absorb and carry away excess heat from the engine.

Which component circulates coolant through the engine and radiator?

The water pump.

What device regulates coolant flow to maintain operating temperature?

The thermostat.

What part of the cooling system dissipates heat from coolant to outside air?

The radiator.

What is the primary function of engine oil?

To lubricate engine components, reducing friction and heat.

Which pump forces oil through the engine’s lubrication passages?

The oil pump.

Where is engine oil stored when the engine is off?

In the oil pan.

What component atomizes and delivers fuel to the intake air stream?

The fuel injector.

Which part supplies pressurized fuel to the injectors?

The electric fuel pump.

What distributes outside air to the cylinders?

The intake manifold.

What does the ignition coil do?

Transforms low battery voltage into high voltage for the spark plugs.

What device times and routes high voltage to the correct spark plug in older systems?

The distributor.

What converts exhaust pollutants into less harmful substances?

The catalytic converter.

What unit measures energy in the SI system?

The joule.

State Newton’s second law of motion.

Force equals mass times acceleration (F = m·a).

Define kinetic energy.

The energy an object possesses due to its motion.

What is static friction?

The force that prevents stationary objects from starting to move relative to each other.

According to Boyle’s Law, how are pressure and volume related for a fixed amount of gas at constant temperature?

They are inversely proportional (P₁V₁ = P₂V₂).

Which simple machine consists of a rigid bar pivoting around a fulcrum?

A lever.

What is mechanical advantage?

The factor by which a machine multiplies input force.

How is gear ratio determined?

By the proportional number of teeth on meshing gears.

What does a transmission do in a drivetrain?

Provides variable power and torque to the vehicle’s wheels.

What is independent suspension?

A system that allows each wheel to move vertically without affecting the others.

What component converts brake-pedal force into hydraulic pressure?

The master cylinder.

Name two common measuring hand tools in the shop.

Rulers and calipers (other acceptable answers include micrometers).

Which tool applies torque in only one direction using interchangeable sockets?

A ratchet.

What is the primary purpose of pliers?

To grip and manipulate objects with mechanical advantage.

What is the function of a CV joint?

To transfer torque to drive wheels at a constant speed while accommodating steering and suspension movement.

What does Pascal’s Law state?

A pressure change in an enclosed fluid is transmitted uniformly in all directions.

Define torque.

A measure of rotational force applied at a distance from a pivot.

What does a muffler do?

Reduces exhaust noise by absorbing sound waves.

Give one example of a second-class lever.

A wheelbarrow (other acceptable examples include a nutcracker).

What is efficiency in the context of simple machines?

The percentage of input power converted into useful output work or movement.