Understanding the Four-Stroke Engine

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

• Compression

• Intake

• Power

• Exhaust

During the compression stage of a four-stroke engine, what happens to the air-fuel mixture?

• It is ignited by the spark plug.

• It is expelled from the cylinder.

• It is compressed to a smaller volume.

• It is mixed with oil.

Explain how the power stroke in a four-stroke engine contributes to the engine's operation. Use evidence from the cycle stages to support your answer.

• The power stroke releases exhaust gases, which are expelled from the engine.

• The power stroke compresses the air-fuel mixture, preparing it for ignition.

• The power stroke ignites the air-fuel mixture, causing an explosion that pushes the piston down.

• The power stroke draws in fresh air and fuel into the cylinder.

Which stage of the four-stroke cycle involves the expulsion of exhaust gases from the cylinder?

• Intake

• Compression

• Power

• Exhaust

Describe the sequence of events in the four-stroke cycle and explain how each stage contributes to the engine's efficiency.

• Intake, Compression, Power, Exhaust; each stage prepares the engine for the next.

• Compression, Power, Exhaust, Intake; each stage reduces engine efficiency.

• Power, Exhaust, Intake, Compression; each stage is independent of the others.

• Exhaust, Intake, Compression, Power; each stage decreases engine power.

What is the primary purpose of the intake stroke in a four-stroke engine?

• To expel exhaust gases from the cylinder.

• To compress the air-fuel mixture.

• To draw air and fuel into the cylinder.

• To ignite the air-fuel mixture.

During which stage of the four-stroke cycle is the piston moving upwards and compressing the air-fuel mixture?

• Intake

• Compression

• Power

• Exhaust

Analyze the role of the exhaust stroke in maintaining the efficiency of a four-stroke engine. Provide reasoning for your answer.

• The exhaust stroke removes burnt gases, allowing fresh air-fuel mixture to enter.

• The exhaust stroke compresses the air-fuel mixture for better combustion.

• The exhaust stroke ignites the air-fuel mixture for power generation.

• The exhaust stroke draws in air and fuel for the next cycle.

What happens during the power stroke of a four-stroke engine?

• The piston moves up, compressing the air-fuel mixture.

• The piston moves down, driven by the explosion of the air-fuel mixture.

• The piston moves up, expelling exhaust gases.

• The piston moves down, drawing in air and fuel.

In a four-stroke engine, why is it important for the exhaust valve to open during the exhaust stroke?

• To allow fresh air to enter the cylinder.

• To release the pressure built up during the power stroke.

• To ignite the air-fuel mixture.

• To compress the air-fuel mixture.