Fuel injection pumps for internal combustion engines

796,444. Fuel injection pumps. NAPIER & SON, Ltd., D. Jan. 14, 1957 [Feb. 29, 1956], No. 6385/56. Class 102(1). In a fuel injection pump of the kind comprising a barrel 11 in which slides a plunger which delivers fuel past a delivery valve 14 to the fuel delivery pipe or pipes, the delivery valve chamber 12 and the pump barrel 11 are clamped together by a ring nut 20. The valve 14 seats on an insert 13. A sleeve 25, made of material having a low modulus of elasticity compared with the materials of the other parts of the pump, is inserted between the shoulder 24 of the chamber 12 and the shoulder 23 of the insert 13. On clamping the chamber 12 and barrel 11 by the ring nut 20 the sleeve 25 is compressed substantially greater than the extension produce between the chamber and the barrel by the reaction to the pumping pressure so that although these parts extend, the sleeve 25 will extend by the same amount and this sleeve still retains the remainder of its initial compression thereby exerting a clamping force between the surfaces 21 and 22 of the barrel and insert thus obviating leakage between them. In the embodiment described the pump body is of aluminium or aluminium alloy and the sleeve 25 of steel to Ministry of Supply Aircraft Material Specification DTD 247.