Flow control system

A fluid metering device for use in a gaseous fuel injection system for an internal combustion engine comprising:

• (a) a body defining an inlet fluid manifold and a metered fluid manifold;
• (b) a fluid inlet for introducing fluid into the inlet fluid manifold;
• (c) a plurality of bi-stable fluid flow control valves for communication between the inlet fluid manifold and the metered fluid manifold, each valve including an orifice and a movable plunger for closing the orifice, the orifice of each valve being between the converging portion and the diverging portion of a nozzle,
• (d) valve actuators for opening and closing the valves;
• (e) a fluid outlet for passage of metered fluid from the metered fluid manifold;
• (f) sensors provided in communication with the inlet fluid manifold to determine parameters of the inlet fluid and the metered fluid sufficient to determine the potential mass flow of fluid through each of the valves;
• (g) valve control means for activating the valve actuators to open the valves in combinations and for time intervals to give a desired total mass flow of fluid through the valves;
• and
• (h) a heating fluid passage extending through the body for heating the body to compensate, in part at least, for the cooling of the fluid which takes place on expansion of the fluid passing through the valve orifices, said heating fluid passage being formed of a plurality of intersecting bores, control means being provided for controlling the flow of heating fluid through the heating passage, said control means including a solenoid-operated valve provided in an inlet of the passage.