Quiz on Four-Stroke Engine

How to Understand the Four-Stroke Engine

Objective: To understand the working process of a four-stroke engine.

Materials Needed:

• Diagram of a four-stroke engine

• Engine model (optional)

Steps:

1. Intake Stroke:

   • The intake valve opens, and the piston moves down the cylinder.

   • This creates a vacuum that draws in a mixture of air and fuel into the combustion chamber.

2. Compression Stroke:

   • The intake valve closes, and the piston moves back up the cylinder.

   • This compresses the air-fuel mixture, making it more volatile and ready for ignition.

3. Power Stroke:

   • At the top of the compression stroke, the spark plug ignites the compressed air-fuel mixture.

   • The explosion forces the piston down the cylinder, creating power that turns the crankshaft.

4. Exhaust Stroke:

   • The exhaust valve opens, and the piston moves back up the cylinder.

   • This expels the burnt gases from the combustion chamber through the exhaust valve.

Conclusion: Understanding the four-stroke engine involves knowing the sequence of intake, compression, power, and exhaust strokes. Each stroke plays a crucial role in the engine's operation, converting fuel into mechanical energy efficiently.

Match the following strokes of a four-stroke engine with their primary purposes.

• Power Stroke

• To ignite the air-fuel mixture

• Compression Stroke

• To compress the air-fuel mixture

• Exhaust Stroke

• To expel burnt gases from the combustion chamber

• Intake Stroke

• To draw in the air-fuel mixture

How to Understand the Four-Stroke Engine

Objective: To understand the working process of a four-stroke engine.

Materials Needed:

• Diagram of a four-stroke engine

• Engine model (optional)

Steps:

1. Intake Stroke:

   • The intake valve opens, and the piston moves down the cylinder.

   • This creates a vacuum that draws in a mixture of air and fuel into the combustion chamber.

2. Compression Stroke:

   • The intake valve closes, and the piston moves back up the cylinder.

   • This compresses the air-fuel mixture, making it more volatile and ready for ignition.

3. Power Stroke:

   • At the top of the compression stroke, the spark plug ignites the compressed air-fuel mixture.

   • The explosion forces the piston down the cylinder, creating power that turns the crankshaft.

4. Exhaust Stroke:

   • The exhaust valve opens, and the piston moves back up the cylinder.

   • This expels the burnt gases from the combustion chamber through the exhaust valve.

Conclusion: Understanding the four-stroke engine involves knowing the sequence of intake, compression, power, and exhaust strokes. Each stroke plays a crucial role in the engine's operation, converting fuel into mechanical energy efficiently.

During which stroke does the spark plug ignite the air-fuel mixture?

• Intake Stroke

• Compression Stroke

• Power Stroke

• Exhaust Stroke

How to Understand the Four-Stroke Engine

Objective: To understand the working process of a four-stroke engine.

Materials Needed:

• Diagram of a four-stroke engine

• Engine model (optional)

Steps:

1. Intake Stroke:

   • The intake valve opens, and the piston moves down the cylinder.

   • This creates a vacuum that draws in a mixture of air and fuel into the combustion chamber.

2. Compression Stroke:

   • The intake valve closes, and the piston moves back up the cylinder.

   • This compresses the air-fuel mixture, making it more volatile and ready for ignition.

3. Power Stroke:

   • At the top of the compression stroke, the spark plug ignites the compressed air-fuel mixture.

   • The explosion forces the piston down the cylinder, creating power that turns the crankshaft.

4. Exhaust Stroke:

   • The exhaust valve opens, and the piston moves back up the cylinder.

   • This expels the burnt gases from the combustion chamber through the exhaust valve.

Conclusion: Understanding the four-stroke engine involves knowing the sequence of intake, compression, power, and exhaust strokes. Each stroke plays a crucial role in the engine's operation, converting fuel into mechanical energy efficiently.

During the power stroke, what is the effect of the explosion on the piston?

• It moves up the cylinder.

• It remains stationary.

• It moves down the cylinder, generating power.

• It opens the intake valve.

How to Understand the Four-Stroke Engine

Objective: To understand the working process of a four-stroke engine.

Materials Needed:

• Diagram of a four-stroke engine

• Engine model (optional)

Steps:

1. Intake Stroke:

   • The intake valve opens, and the piston moves down the cylinder.

   • This creates a vacuum that draws in a mixture of air and fuel into the combustion chamber.

2. Compression Stroke:

   • The intake valve closes, and the piston moves back up the cylinder.

   • This compresses the air-fuel mixture, making it more volatile and ready for ignition.

3. Power Stroke:

   • At the top of the compression stroke, the spark plug ignites the compressed air-fuel mixture.

   • The explosion forces the piston down the cylinder, creating power that turns the crankshaft.

4. Exhaust Stroke:

   • The exhaust valve opens, and the piston moves back up the cylinder.

   • This expels the burnt gases from the combustion chamber through the exhaust valve.

Conclusion: Understanding the four-stroke engine involves knowing the sequence of intake, compression, power, and exhaust strokes. Each stroke plays a crucial role in the engine's operation, converting fuel into mechanical energy efficiently.

Explain the role of the piston during the compression stroke.

• It moves down to draw in air-fuel mixture.

• It remains stationary to allow combustion.

• It moves up to compress the air-fuel mixture.

• It opens the exhaust valve.

How to Understand the Four-Stroke Engine

Objective: To understand the working process of a four-stroke engine.

Materials Needed:

• Diagram of a four-stroke engine

• Engine model (optional)

Steps:

1. Intake Stroke:

   • The intake valve opens, and the piston moves down the cylinder.

   • This creates a vacuum that draws in a mixture of air and fuel into the combustion chamber.

2. Compression Stroke:

   • The intake valve closes, and the piston moves back up the cylinder.

   • This compresses the air-fuel mixture, making it more volatile and ready for ignition.

3. Power Stroke:

   • At the top of the compression stroke, the spark plug ignites the compressed air-fuel mixture.

   • The explosion forces the piston down the cylinder, creating power that turns the crankshaft.

4. Exhaust Stroke:

   • The exhaust valve opens, and the piston moves back up the cylinder.

   • This expels the burnt gases from the combustion chamber through the exhaust valve.

Conclusion: Understanding the four-stroke engine involves knowing the sequence of intake, compression, power, and exhaust strokes. Each stroke plays a crucial role in the engine's operation, converting fuel into mechanical energy efficiently.

If the exhaust valve does not open during the exhaust stroke, what is the likely outcome?

• The engine will run more efficiently.

• The burnt gases will remain in the combustion chamber.

• The power stroke will be enhanced.

• The intake stroke will be affected.

How to Understand the Four-Stroke Engine

Objective: To understand the working process of a four-stroke engine.

Materials Needed:

• Diagram of a four-stroke engine

• Engine model (optional)

Steps:

1. Intake Stroke:

   • The intake valve opens, and the piston moves down the cylinder.

   • This creates a vacuum that draws in a mixture of air and fuel into the combustion chamber.

2. Compression Stroke:

   • The intake valve closes, and the piston moves back up the cylinder.

   • This compresses the air-fuel mixture, making it more volatile and ready for ignition.

3. Power Stroke:

   • At the top of the compression stroke, the spark plug ignites the compressed air-fuel mixture.

   • The explosion forces the piston down the cylinder, creating power that turns the crankshaft.

4. Exhaust Stroke:

   • The exhaust valve opens, and the piston moves back up the cylinder.

   • This expels the burnt gases from the combustion chamber through the exhaust valve.

Conclusion: Understanding the four-stroke engine involves knowing the sequence of intake, compression, power, and exhaust strokes. Each stroke plays a crucial role in the engine's operation, converting fuel into mechanical energy efficiently.

What is the first stroke in the four-stroke engine cycle?

• Compression Stroke

• Power Stroke

• Exhaust Stroke

• Intake Stroke

How to Understand the Four-Stroke Engine

Objective: To understand the working process of a four-stroke engine.

Materials Needed:

• Diagram of a four-stroke engine

• Engine model (optional)

Steps:

1. Intake Stroke:

   • The intake valve opens, and the piston moves down the cylinder.

   • This creates a vacuum that draws in a mixture of air and fuel into the combustion chamber.

2. Compression Stroke:

   • The intake valve closes, and the piston moves back up the cylinder.

   • This compresses the air-fuel mixture, making it more volatile and ready for ignition.

3. Power Stroke:

   • At the top of the compression stroke, the spark plug ignites the compressed air-fuel mixture.

   • The explosion forces the piston down the cylinder, creating power that turns the crankshaft.

4. Exhaust Stroke:

   • The exhaust valve opens, and the piston moves back up the cylinder.

   • This expels the burnt gases from the combustion chamber through the exhaust valve.

Conclusion: Understanding the four-stroke engine involves knowing the sequence of intake, compression, power, and exhaust strokes. Each stroke plays a crucial role in the engine's operation, converting fuel into mechanical energy efficiently.

Evaluate the efficiency of a four-stroke engine. What factor contributes to its efficiency?

• The number of strokes in a cycle

• The use of a spark plug for ignition

• The ability to expel burnt gases completely

• The size of the combustion chamber

How to Understand the Four-Stroke Engine

Objective: To understand the working process of a four-stroke engine.

Materials Needed:

• Diagram of a four-stroke engine

• Engine model (optional)

Steps:

1. Intake Stroke:

   • The intake valve opens, and the piston moves down the cylinder.

   • This creates a vacuum that draws in a mixture of air and fuel into the combustion chamber.

2. Compression Stroke:

   • The intake valve closes, and the piston moves back up the cylinder.

   • This compresses the air-fuel mixture, making it more volatile and ready for ignition.

3. Power Stroke:

   • At the top of the compression stroke, the spark plug ignites the compressed air-fuel mixture.

   • The explosion forces the piston down the cylinder, creating power that turns the crankshaft.

4. Exhaust Stroke:

   • The exhaust valve opens, and the piston moves back up the cylinder.

   • This expels the burnt gases from the combustion chamber through the exhaust valve.

Conclusion: Understanding the four-stroke engine involves knowing the sequence of intake, compression, power, and exhaust strokes. Each stroke plays a crucial role in the engine's operation, converting fuel into mechanical energy efficiently.

Compare the four-stroke engine to a two-stroke engine. Which of the following is true?

(a)  

• A four-stroke engine has fewer movi
• A four-stroke engine completes a po
• A four-stroke engine is generally m
• A four-stroke engine does not requi

How to Understand the Four-Stroke Engine

Objective: To understand the working process of a four-stroke engine.

Materials Needed:

• Diagram of a four-stroke engine

• Engine model (optional)

Steps:

1. Intake Stroke:

   • The intake valve opens, and the piston moves down the cylinder.

   • This creates a vacuum that draws in a mixture of air and fuel into the combustion chamber.

2. Compression Stroke:

   • The intake valve closes, and the piston moves back up the cylinder.

   • This compresses the air-fuel mixture, making it more volatile and ready for ignition.

3. Power Stroke:

   • At the top of the compression stroke, the spark plug ignites the compressed air-fuel mixture.

   • The explosion forces the piston down the cylinder, creating power that turns the crankshaft.

4. Exhaust Stroke:

   • The exhaust valve opens, and the piston moves back up the cylinder.

   • This expels the burnt gases from the combustion chamber through the exhaust valve.

Conclusion: Understanding the four-stroke engine involves knowing the sequence of intake, compression, power, and exhaust strokes. Each stroke plays a crucial role in the engine's operation, converting fuel into mechanical energy efficiently.

Match the following components with their functions in a four-stroke engine.

• Allows burnt gases to exit the combustion chamber

• Exhaust Valve

• Opens to allow the air-fuel mixture into the combustion chamber

• Intake Valve

• Moves up and down to create pressure and power

• Piston

• Ignites the compressed air-fuel mixture

• Spark Plug

How to Understand the Four-Stroke Engine

Objective: To understand the working process of a four-stroke engine.

Materials Needed:

• Diagram of a four-stroke engine

• Engine model (optional)

Steps:

1. Intake Stroke:

   • The intake valve opens, and the piston moves down the cylinder.

   • This creates a vacuum that draws in a mixture of air and fuel into the combustion chamber.

2. Compression Stroke:

   • The intake valve closes, and the piston moves back up the cylinder.

   • This compresses the air-fuel mixture, making it more volatile and ready for ignition.

3. Power Stroke:

   • At the top of the compression stroke, the spark plug ignites the compressed air-fuel mixture.

   • The explosion forces the piston down the cylinder, creating power that turns the crankshaft.

4. Exhaust Stroke:

   • The exhaust valve opens, and the piston moves back up the cylinder.

   • This expels the burnt gases from the combustion chamber through the exhaust valve.

Conclusion: Understanding the four-stroke engine involves knowing the sequence of intake, compression, power, and exhaust strokes. Each stroke plays a crucial role in the engine's operation, converting fuel into mechanical energy efficiently.

Which of the following statements best describes the combustion process in a four-stroke engine?

• It occurs during the intake stroke.

• It is a continuous process throughout all strokes.

• It occurs when the spark plug ignites the compressed air-fuel mixture.

• It is only necessary during the exhaust stroke.