Patent GB-709412-A (GB)
Title: Improvements in and relating to the supply of fuel to internal combustion engines
IPC: F02M61/00
Filed: 1949-06-08
Abstract: 709,412. Supplying liquid fuel to cylinders. BONDI, J. W., and ASSOCIATED BRITISH OIL ENGINES, Ltd. July 14, 1950 [June 8, 1949], No. 15334/49. Class 7(3) In the compression-ignition engine of the kind comprising a cylinder head 2, Fig. 1, and a piston 1, a recess 15 in the piston and an obturator 3 projecting from the head 2, for example, and capable of entering the recess 15 as the piston approaches T.D.C. in order to divide the combustion chamber into two volumes in which volume reduction occurs at different rates, and a passage for displacement of air from one volume to another, there is provided a receiving chamber 6 for metered fuel in or adjacent the passage 7 and restricted outlet, for example between a valve 28 and its seat, for emergence of fuel from the chamber to enable atomization of the fuel to be effected by pressure and/or induction by the displacement air so that a stream of air in intimate admixture with atomized fuel enters the recess 15. The obturator 3 has an axial feed duct 4 connected to a low-pressure pump (not shown), which duct opens into the chamber 6 through a spring-loaded non-return valve 21 provided with a stem 24 that is housed for a part of its length in the duct 4. The chamber 6 has two lateral openings 7 into the combustion chamber 17 and a lower opening 27 normally closed by the spring- loaded valve 28. The piston 1 incorporates the pre-combustion recess 15 having an offset cylindrical opening 16 so that as the piston approaches T.D.C. an " air squish " effect occurs and causes air to enter the chamber 6 through the openings 7 and operate valve 28 whereby a restricted conical duct is provided between the seat and valve face through which fuel is expelled in atomized form into the recess 15. At a further point in the cycle, when the pressure in the fuel chamber drops, the chamber is refilled with fuel by the pump through the non-return valve 21. In a modification, the fuel passing into the piston recess is atomized by passing between a fluted member and the lower opening in the obturator, which fluted member is integral with the non-return valve. In another modification, the lateral openings each comprises a portion formed as a Venturi and opening into each latter is an atomizing duct leading to the fuel chamber. The high velocity of air through each Venturi induces fuel through the atomizing ducts, the two atomized fuel streams meeting and passing through an opening in the lower surface of obturator into the piston recess. The fuel supply to the chamber may be controlled by a needle valve instead of a pump. In a further modification, the fuel chamber 6, Fig. 4, opens to the exterior through radial passages 42 and downwardly extending atomizing bores 43 so that as the obturator enters the opening 16 the air forced from the combustion chamber 17 into the recess 15 passes the ends of bores 43 at high velocity and induces fuel therefrom. The supply of fuel into duct 4 is under the control of a needle valve (not shown) and the peripheral surface of the obturator may be convex in the zone of the atomizing bores 43. The recess may be provided in the cylinder head and the obturator on the piston, the fuel being expelled from the receiving chamber into the recess by the "squish" effect; the fuel could also be induced from the receiving chamber as described above. The obturator body may be axially adjustable to facilitate timing. The Provisional Specification comprises an embodiment in which the fuel receiving chamber opens directly to the lower exterior of the obturator through atomizing bores, the obturator being located in the cylinder head.