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.

Abstract: An internal combustion engine has a fuel injector in a side wall of each cylinder to direct a fuel jet onto a flat or concave impingement surface of a shield projecting into the cylinder from the cylinder head, to atomize the fuel in the vicinity of the sparking plug electrodes with minimal wetting of the cylinder walls and of the plug electrodes. The piston head is formed with an asymmetrically located combustion chamber surrounded by extensive "squish" areas arranged to promote the formation of a fuel vortex in which charge stratification occurs centrifugally.