This is effected by a cam sleeve slidable on the crankshaft, or other shaft driven from the crankshaft, and connected with the reversing mechanism. This cams acts to open the suction-valve of the pump, or to open a valve between the pressure and suction side of the pump, during the pressure stroke of the pump.
The lift and the duration of the opening of the valve may be determined by means of a wedge or by adjusting the fulcrum of the lever manually or by a governor.The valve may be fitted with a small pressure relieving valve.
The above-mentioned sleeve is slidable but not rotatable in relation to the shaft, and is provided with two recesses, one for each direction of rotation of the engine, and is adapted to operate the suction-valve of the fuel-pump by means of a rod or its equivalent.
In another arrangement the sleeve is provided with two cams displaceable in relation to each other and adapted to operate the suction-valve of the fuel-pump by means of a lever and a rod or the like.
It will be seen that the invention consists essentially in the combination with the fuel-pump of means for keeping the suction-valve or valves, or a corresponding valve or valves, or the pump open during the whole pressure stroke of the pump, or the greater part thereof, when the engine runs in a direction opposite to that which the controlling means of the engine are adjusted.