Patent GB-754263-A (GB)
Title: Improvements in and relating to adjusting devices for free-piston engines
IPC: F02B71/00
Filed: 1954-04-23
Abstract: 754,263. Combustion product power plant; direct-acting engines; regulating. SOC. D'ETUDES ET DE PARTICIPATIONS EAU, GAZ, ELECTRICITE, ENERGIE. SOC. ANON. April 23, 1954 [April 30, 1953], No. 11865/54. Classes 7(1), 7(2) and 7(6) [Also in Group XXVIII] In a free piston engine supplied with fuel by an injection pump 25, Fig. 1, the control rod 30 of which is actuated in accordance with the load un the engine, a supplementary adjusting means, consisting of an auxiliary pump 33, directly responsive to variations in the outer dead points of the engine piston 9 reduces the supply of fuel to the injectors 13 by an amount varying in dependence upon the length of stroke of the piston 9. As shown, Fig. 1, the engine comprises opposed power pistons 9 each of which is attached to a compressor piston 10 supplying scavenging air to a receiver 7, the pistons 9 being synchronized by a linkage device 15, 16 as described in Specification 697,803. One piston 9 controls the intake ports 2 and the other the exhaust ports 3 connected to a passage 14 leading to a turbine driven by the engine exhaust gases. The injection pump 25 is actuated by a cam 28 on a slide 29 attached to the piston 10 and a second cam 39 thereon actuates the auxiliary pump 33 connected to the delivery pipe 31 of the pump 25. The cam 39 is provided with a horizontal portion 39c which reaches the roller 40 at the end of an outstroke of piston 10 of average length and portions 39a, 39b, which come into operation when the piston stroke tends to rise above or fall below the permitted maximum and minimum values. On an average stroke the cam part 39c raises plunger 33 and the fuel in the space 32 is by-passed through check valve 36 and space 37 to a return pipe 38, whereby on the return stroke of the plunger 33 a vacuum is formed in the pipe 31, which vacuum reduces the amount of fuel injected through the injector 13 on the next pumping stroke of the pump 25. If the piston stroke approaches the maximum value the cam part 39a causes a larger reduction in the fuel delivery and if it approaches the minimum value the part 39b causes a smaller reduction in fuel delivery to keep the piston stroke within the permissible limits. In a modification the fiat part 39c of the cam 39 is omitted. In a further modification the pumps 25, 33 are replaced by an injection system, Fig. 5, in which a pump plunger 43 on each stroke charges separate accumulators 50, 57, which deliver respectively through a valve 62 and pipe 69 to an injector in a pre-combustion chamber and through valve 60 and pipe 27a to a direct injection nozzle. The plunger 43 and valve 62 are actuated by a cam 70 connected to the hinge pin of the synchronizing lever 15, Fig. 1, and the supplementary adjustment means comprises a plunger 76 which is actuated between strokes of the plunger 43 by a cam 79 connected to the hinge pin of the synchronizing lever 16. On its upstroke the plunger 76 delivers fuel through a check valve 67 and passages 66, 81, to the supply passage 46 of the pump 43 and on its downstroke valve 67 closes so that a vacuum is formed in the space 77 which reduces the output of the pump 43 on its next pumping stroke. The cam 79 has a shape corresponding to. the cam 39, Fig. 1, and operates in a similar manner.