Patent GB-363114-A (GB)
Title: Improvements in or relating to fuel injection devices for internal combustion engines
IPC: F02M57/02
Filed: 1930-12-04
Abstract: 363,114. Liquid fuel injectors. SULZER FR’RES SOC. ANON., Winterthur, Switzerland. Dec. 4, 1930, No. 36562. Convention date, Dec. 31, 1929. [Class 7 (iii).] In a fuel injector of the kind comprising an accumulator chamber to which fuel is admitted under pressure through a non-return valve, the latter is arranged concentrically within the valve casing, the construction being approximately symmetrical about the longitudinal axis. One of the coacting faces of the non-return valve 9, Fig. 2, is formed on an upward extension of the needle valve 5 controlling the fuel-discharge orifice 4 whilst the other coacting face is formed at the lower end of a hollow plunger 10 located between the injection valve 5 and a spring-loaded accumulator plunger 15. Fuel under pressure admitted at 3 to a chamber 11 retains the injection valve on its seat, but passes through the non-return valve 9 and the axial bores of the valve 5 and plunger 10 to chambers 8, 18; when injection is to take place the supply pressure is reduced. allowing the non-return valve 9 to close whilst the difference in pressure in chambers 8, 11 effects the opening of the injection valve, the fuel being expelled from chamber 18 by the plunger 15, the last portion of the plunger movement closing the valve 5 positively; a sleeve 13 limits the upward travel of the non-return valve member 10. Fig. 4 shows an alternative construction in which the upper end of the needle valve 25 is provided with a conical head 26 which coacts with a seating on the lower end of spring-loaded sleeve 30 to form the non-return valve ; guide ribs 29 are formed on an upward extension of the needle valve 25. Fuel is fed under pressure at 23 and passes through the axial bore 32 of an extension of the sleeve 30, forcing the latter upwardly, thereby admitting fuel to an accumulator chamber 42 surrounding the sleeve and injection valve 25 ; a spring-loaded accumulator plunger 33 effects injection when the supply pressure is reduced. Two further modified constructions, Figs. 5 and 6, are described in which the injector is dependent for its operation on the compressibility of the fuel itself. In Fig. 5 the portion 51 of the non-return valve which is carried by the injection valve 65 is connected by resilient means 49 to a piston 48 formed integrally with the valve 65. The supply pressure forces the fuel through the non-return valve 51 to an inner chamber 62 where its expansion, following a reduction of pressure on the top face of the piston 48, causes the injection valve to lift. A closure member 64 carrying the injection valve seating is so adjusted axially that under normal conditions the extensible .tube 49 forming the resilient means is initially tensioned. In Fig. 6 the moving portion of the non-return valve 77 is formed by a member 76 slidably mounted on the stem 73 of the injection valve and is loaded by a spring 75 which also retains the injection valve on its seat in opposition to the pressure existing in a chamber 86 which is in communication with the accumulator chamber 79. Injection takes place when the pressure is relieved from the exposed end of the stem 73.