PURPOSE: An ellipse engine piston is provided to mount a plurality of cylinders in same area and to improve engine efficiency by changing the shape of piston. CONSTITUTION: An ellipse engine piston comprises follows. A piston of circular shape is made into ellipse shape. The time to disperse intake gas flowing in an engine is reduced. The cylinder is made in ellipse shape to reduce the intake gas dispersing time and make the ventilation smooth. The ellipse cylinder has same exhaust volume of the existing cylinder but makes the more rapid reaction rate than the ideal exhaust volume engine by increasing the number of cylinders.
