In a four-stroke engine, what stroke occurs first?

• A. Exhaust stroke
• B. Power stroke
• C. Intake stroke
• D. Compression stroke

Answer: (C)

In a four-stroke engine, the first stroke that occurs is the intake stroke. During the intake stroke, the intake valve opens and the piston moves down the cylinder, creating a vacuum that draws in a mixture of air and fuel. This is essential for the engine's operation, as it prepares the combustion mixture that will be compressed in the subsequent stroke.

The sequence of events in a four-stroke engine is designed for efficiency and performance, with each stroke play a critical role in the engine cycle. Following the intake stroke, the engine goes through the compression stroke, power stroke, and finally the exhaust stroke. Understanding this sequence is fundamental for students learning about engine function and design.