4-Stroke Engine Theory Quiz

What are the four strokes of a 4-stroke internal combustion engine in their correct operational order?

• Compression, Power, Intake, Exhaust

• Intake, Compression, Power, Exhaust

• Exhaust, Intake, Compression, Power

• Power, Exhaust, Intake, Compression

Which of the following best describes the primary event during the Intake Stroke?

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

• The spark plug ignites the compressed mixture, forcing the piston downward.

• The intake valve opens, and the piston moves downward, drawing in the air-fuel mixture.

• The exhaust valve opens, and the piston moves upward, expelling burned gases.

During which stroke are both the intake and exhaust valves typically closed, allowing for a significant pressure increase?

• Intake Stroke

• Compression Stroke

• Power Stroke

• Exhaust Stroke

What is the primary function of the spark plug in a gasoline 4-stroke engine, and during which stroke does it perform this function?

• To open the intake valve during the intake stroke.

• To create an electrical arc to ignite the air-fuel mixture during the compression stroke.

• To create an electrical arc to ignite the air-fuel mixture during the power stroke.

• To measure the amount of fuel entering the cylinder during the intake stroke.

What is the primary function of the Exhaust Stroke?

• The piston moves downward, drawing in the air-fuel mixture.

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

• The exhaust valve opens, and the piston moves upward, expelling burned gases from the cylinder.

• The spark plug ignites the mixture to create power.

What is the critical role of the crankshaft in a 4-stroke engine's operation?

• It opens and closes the engine's valves.

• It stores the fuel before combustion.

• It converts the linear (up and down) motion of the pistons into rotational motion.

• It filters the oil used in the engine.

Tags

NGSS.MS-PS2-1

NGSS.MS-PS2-2

If an engine has a 'stuck open' exhaust valve, which of the following issues would most likely occur?

• Excessive compression, leading to engine damage.

• A loss of compression and incomplete combustion, leading to misfires.

• Too much fuel entering the cylinder, causing flooding.

• The engine running too cool due to constant airflow.

Tags

NGSS.MS-PS2-2

Why is proper valve timing crucial for the efficient operation of a 4-stroke engine?

• It determines the engine's top speed.

• It ensures the valves open and close at the precise moments to allow for optimal air-fuel intake and exhaust gas expulsion.

• It controls the amount of lubricant sent to the engine cylinders.

• It regulates the engine's temperature.

Tags

NGSS.MS-PS2-2

In a typical 4-stroke engine, how many rotations of the crankshaft occur for one complete cycle (all four strokes)?

• 1 rotation

• 2 rotations

• 3 rotations

• 4 rotations

Which of the following best describes the Power Stroke (also known as the Combustion Stroke)?

• The piston moves downward, drawing in the air-fuel mixture.

• The piston moves upward, pushing out exhaust gases.

• Immediately after compression and ignition, the expanding gases force the piston powerfully downward, rotating the crankshaft.

• The piston moves upward to compress the incoming air-fuel mixture.

Tags

NGSS.MS-PS3-5