Abstract: A rotary diesel engine comprising a casing which forms a working space composed of intersecting cylindrical chambers. A rotor is rotatably positioned in at least one of the chambers and a rotary sealing member is positioned at least in one of the other of the chambers, the rotor having a plurality of radially extending lobes and the rotary sealing member having a plurality of radially extending grooves intermeshing with the lobes. A fuel injection assembly is cooperatively carried by the rotary sealing member and is made up of a manifold, a fuel entry port, fuel injection chambers, and pressure building and metering components for each of the fuel injection chambers. An appropriate actuating device, stationarily located external to the rotary sealing member, provides control for the complete fuel injection assembly.