Revolving piston combustion engine of trochoid type

Claim 1

A rotary piston internal combustion engine of trochoidal type comprising; a housing composed of a shell with a multi-lobed inner surface and of parallel end walls, a polygonal piston mounted for eccentric rotation within said housing, said piston having sealing blades at its vertices which slide along the inner surface of the shell, inlet and outlet ports in the housing at least one spark plug arranged in a hole in the shell and having an endface near the inner surface of the shell, a space in said endface, a center electrode extending into said space and terminating short of said endface, at least one ground electrode extending laterally into said space toward the center electrode to form a spark gap therewith, a recess in said endface extending substantially over the entire outer boundary edge of said space and into the place of said spark gap, the spark plug being arranged in that region of the inner surface of the shell where during passage of a sealing blade no substantial pressure difference prevails between the two working chambers separated from each other by said blade, each flank of the piston being provided with a trough the greater portion of the volume of which lies in the leading part of the flank relative to the direction of rotation of the piston.