Patent ID: RE41262

Claim:
Gas injection system, particularly of methane, for internal combustion engine, comprising: a plurality of electromagnetically controlled injectors, associated to the various cylinders in the engine, a distributing manifold or rail communicating with said injectors, a feeding reservoir of the distributing manifold where pressurised gas is accumulated, a pressure regulating valve interposed in the connection between the reservoir and said distribution manifold, an electronic control unit set up to control the injectors and to control the opening time to meter the amount of gas injected in each cylinder according to the operating conditions of the engine and, an on-off valve arranged on the output of the reservoir, comprising: a valve member, co-operating with a valve seat, spring means tending to push said valve member in the same direction as the flow of gas from said reservoir, towards a closed condition in contact with said valve seat, and a solenoid which can be energized to recall the valve member to an open condition spaced apart from said valve seat, against the action of elastic said spring means, wherein said valve member ( 18 ) is made of metallic material and in that said valve seat is made in a metallic material body , and wherein said solenoid is suited to apply a first higher force of attraction on the valve member which is higher in a first phase of predetermined duration, in order to cause the detachment of the valve member from its seat, and a second force of attraction on the valve member, which is lower than said first force of attraction, in a second subsequent phase to keep the valve member open, so that in the case of excessive flow of gas due to leakage in the tubes downstream with respect to the on-off valve, the valve member will close and also act as a flow limiting valve.