What are four major parts of an elementary engine?

Four major parts of an elementary engine include the cylinder, where fuel and air are mixed and combusted; the piston, which moves up and down to convert combustion energy into mechanical work; the crankshaft, which translates the piston's linear motion into rotational motion; and the camshaft, which controls the opening and closing of the engine's valves. Together, these components work in harmony to facilitate the engine's operation and power output.