Working Principle: Almost exclusively 4-Stroke for automotive and commercial setups, though massive marine propulsion platforms utilize 2-Stroke configurations.Cylinder Configurations: Single-cylinder (small pumps/generators), Inline 4 to 6 cylinders (automotive/mid-range industrial), or V-Type (V8, V12) configurations for heavy machinery.Bore x Stroke: The internal diameter of the cylinder vs. the total distance the piston travels. Diesel engines are typically under-square (long-stroke) configurations to maximize low-end rotational torque.Compression Ratio: Ranging from 16:1 up to 22:1. This high ratio compresses air intensely until it reaches temperatures capable of auto-igniting diesel fuel without a spark plug.