Abstract: There is described a method of controlling air intake flow of an internal combustion engine (1), the method including the steps of calculating a reference airflow (AREF) as the sum of a feed-forward contribution (AFF), calculated as a function of the reference air/fuel ratio ((A/F)REF) to be obtained in the combustion chamber, and a feed-back contribution (AFB), calculated as a function of the oxygen concentration (% O2) of the exhaust gas; and closed-loop controlling the air intake flow of the engine so that it equals the reference airflow (AREF).

Abstract: A recirculating assembly is provided for a fuel cell system having an electrochemical conversion unit which receives a combustible fluid at an inlet, and supplies electric energy at an electrical output, surplus combustible fluid at a first fluid outlet, and a waste fluid at a second fluid outlet. The recirculating assembly has a compressor for increasing the pressure of the surplus combustible fluid not used by the conversion unit, so as to make it once more available to the conversion unit. The drive is powered by residual energy of the waste fluid to drive the compressor.

Abstract: The common rail supplies a number of injectors of the cylinders of the engine, and is supplied by a constant-displacement high-pressure pump in turn supplied by a low-pressure, variable-delivery, variable-pressure, motor-driven pump. The control device has an electronic control unit for receiving signals indicating operating conditions of the engine; the suction side of the high-pressure pump has a choke; and the control unit controls the motor-driven pump to vary the fuel pressure upstream from the choke between a predetermined maximum value and a predetermined minimum value, so as to regulate the fuel intake of the high-pressure pump within a predetermined range.

Abstract: The injector has a nozzle closed by a rod which is movable by the fuel pressure in a control chamber having a discharge conduit closed by a plug controlled by an electromagnet. The rod is movable, from a closed position closing the nozzle, to effect a maximum travel, so that the amount of fuel injected following the maximum travel is greater than a maximum amount of fuel required by the power curve. To classify the injectors, a series of injectors is prepared with corresponding rods movable from the closed position to effect the maximum travel; and the amount of fuel injected by each injector, after two strokes of the respective rod smaller than the maximum travel, is tested.