Four-Stroke Engine Timing Diagrams Explained

This course explains how four-stroke engine timing diagrams represent key engine events in relation to crankshaft rotation and piston position. It covers the complete 720-degree crankshaft cycle and explains when the inlet and exhaust valves open and close, as well as when ignition or fuel injection occurs.

The course follows the timing sequence through the intake, compression, power, and exhaust strokes. It explains IVO, IVC, EVC, EVO, ignition advance, fuel injection start, valve overlap, scavenging, and the relationship between valve timing and engine speed.

The course also introduces the two-to-one crankshaft-to-camshaft speed relationship and explains how variable valve timing can alter valve opening and closing points. Understanding timing diagrams provides insight into airflow, combustion, engine efficiency, power output, fuel efficiency, and emissions.