How a 4-Stroke Engine Works: Intake and Compression Strokes Explained #3711596 (License: Personal Use)

The left diagram illustrates the intake stroke, where the piston moves downward, drawing in an air-fuel mixture as the intake valve opens; the right diagram shows the compression stroke, where the piston rises, compressing the mixture with both valves sealed. Red arrows indicate crankshaft rotation direction and piston movement, while blue highlights the intake/exhaust ports and orange denotes the combustion chamber.

Used in automotive education, mechanical engineering tutorials, and DIY repair guides to explain fundamental engine operation; matches user intent for understanding basic internal combustion principles.