What is the structure of piston engine?
Ummmm…very very vague question. Your basic engine has a block with champers for pistons to move in and out of, the cylinders, pistons connect to the crankshaft which outputs power to the transmission. Top of the block has the valves to allow air to flow in and out. Valves are controlled by at least one or more camshafts. Camshafts are connected to a timing chain or belt and attach in various ways to the crankshaft. So for each revolution of the engine, the pistons and valves stay in sync. Most engines now a days use a set of fuel injectors the atomize the fuel to mix with the air to create a hopefully stoichiometric mixture that will burn, NOT explode, above the piston in the chamber between the top of the piston and the recess in the cylinder head.
