1 Stroke is defined as 1 movement of piston from top dead center to bottom dead center.

A 2 stroke engine has 2 strokes in its one working cycle i.e.(i) Suction stroke and

(ii) exhaust stroke.

4 stroke engine has 4 strokes in one working cycle i.e.

(i) suction stroke

(ii) compression stroke

(iii) power or expansion stroke

(iv) exhaust stroke

So , Now According to your Que. an engine which completed its one working cycle in 8 strokes is to be called a 8 stroke engine. But unfortunately till now, no engine is doing so.

So in end till now there is no 8 stroke practical engine in world.

Hopefully its sufficient….!!