Abstract: A LPG reservoir for an internal combustion engine adapted to be operated selectively with LPG and gasoline includes a pump unit which has connecting elements for a LPG outlet conduit and a LPG return conduit, as well as a sensor device for sensing the level of LPG in the reservoir.

Abstract: An internal combustion engine is provided with a methane feed system including a plurality of methane injection devices respectively associated with the various cylinders of the engine. The methane injection devices are mounted within respective seats communicating with a distributing conduit or rail for feeding methane. The seats for the injection devices in the rail are formed in an auxiliary body separate from the intake manifold and the head of the engine. An electronic control unit provides for the control of the injection devices on the basis of signals indicative of the parameters of operation of the engine so as to carry out the methane injection at each cylinder when the rotational speed of the engine is lower than a predetermined threshold when the intake valve of the cylinder is open.

Abstract: There is described an internal combustion engine able to operate selectively either with gasoline injection or with injection of LPG in a liquid state, which is obtained from an engine able to operate only with gasoline injection.