Rotary piston internal combustion engine

A rotary piston internal combustion engine having a housing with a two arc trochoidal cavity and a three sided piston for orbital and rotary movement in the cavity and a shaft supporting the piston, means for supplying a stratified charge to the cavity comprising first axially spaced and second axially spaced fuel-air inlets in said housing and controlled by said piston as the piston moves in the cavity, said first inlets supplying a lean mixture to said cavity and said second inlets supplying a rich mixture to said cavity, the positioning of said inlets being such that said first inlets open before said second inlets, first supply passage means connected to said first inlets and inclined in the direction of movement of the piston to supply the lean mixture to the cavity near the axial ends of said piston, a circumferential groove formed in about the axial center of each side of the piston, second supply passage means connected to said second inlets and inclined in the direction of piston movement and toward the axial central region of the piston for the supply of the rich mixture to the cavity toward the axially central region of the piston and to the groove in the respective side of the piston, and ignition means positioned in the housing to ignite the rich mixture therein.