Abstract: For a multi-cylinder internal combustion engine having at least two sets of engine cylinders, a fuel intake system comprises at least first and second intake passages communicated to the engine cylinders of the respective sets and through which respective primary combustible mixtures are supplied into the engine cylinders of the sets. First and second connecting passages are provided for communication between the first and second intake passage at respective positions downstream of throttle valves in the intake passages. The first connecting passage has an intermediate portion communicated to an idle and low-speed fuel circuit for distributing uniformly an idling mixture into the first and second intake passages and has an effective cross sectional surface area smaller than that of the second connecting passage.

Abstract: Rotary piston engine comprising a casing and a substantially tri-angular rotor disposed in the trochoidal cavity of the casing. The casing is provided with a take-out port for drawing compressed air from the compressing working and a discharge port located to open to the exhaust working chamber. The take-out port is connected through a throttle-controlled valve with the discharge port and so located that squish flow directed to the ignition area is weakened by taking out a part of the compressed gas through the take-out port.

Abstract: Rotary piston engine having a first intake port formed in rotor housing and one or more second intake ports formed either one or both of the rotor and side housings. The first intake port supplies relatively rich air-fuel mixture having mixing ratio of 2 to 6 and the second intake port supplies air or relatively lean mixture in such a manner that the total air-fuel ratio becomes 15 to 20.