Fuel pumping apparatus

A fuel pumping apparatus for supplying fuel to a combustion chamber of a compression ignition engine comprising in combination, a pumping plunger housed within a bore, means driven by a drive shaft which is connected in use to or forms part of a rotary part of the engine for positively reciprocating the plunger within the bore, the bore defining with the plunger first and second pump chambers, the volume of the second chamber increasing and that of the first chamber decreasing during movement of the plunger in a fuel delivery direction and vice versa as the plunger is moved in the opposite fuel filling direction, a shuttle slidable within a cylinder, an outlet from one end of the cylinder for connection in use to a fuel injection nozzle of the associated engine, a fuel inlet to said second chamber, a first non-return valve in said fuel inlet arranged to allow fuel flow into said second chamber, an accumulator in which fuel can be stored under pressure, a second non-return valve in a conduit connecting said second chamber with said accumulator, first valve means operable to connect said second chamber with said one end of the cylinder whereby during movement of the plunger in the filling direction fuel will flow to said one end of the cylinder and displace said shuttle, said second non-return valve being set to open at a higher pressure than is required to cause movement of the shuttle, an electromagnetically operated valve connected in a flow path between the other end of the cylinder and the accumulator, said electromagnetically operable valve being operable to prevent escape of fuel from the other end of the cylinder during movement of the shuttle away from said one end of the cylinder thereby to determine the excursion of the shuttle, second valve means operable to connect said first chamber with said accumulator during movement of the pumping plunger in the filling direction and third valve means operable to connect said first chamber with the other end of the cylinder during movement of the pumping plunger in the pumping direction.