Patent GB-640399-A (GB)
Abstract: 640,399. Two-stroke engines. BRUNEL, H. Dec. 29, 1947, Nos. 34371 and 34372. Convention dates, Nov. 6, 1946 and Oct. 21, 1947. [Classes 7 (ii) and 7 (iii)] [Also in Group XXVIII] Twin cylinders 1, 2, interconconnected by a passage 25, contain pistons 5, 6 connected to the same crankpin 17 and which on the downstroke compress repectively scavenging air entering the space 9 through a port 27 controlled by a port 27a in the piston 5, and combustible mixture entering the space 10 through a port 36 concontrolled by a port 37 in the piston6; in modifications air is compressed in the space 10. The piston 5 is slightly in advance of the piston 6 so that an exhaust port 26 is first uncovered; a port 28 then opens a passage 29 through which scavenging air is forced into the cylinder spaces 8, 7 past a deflector 35. A port 31 then opens a transfer passage 34 and combustible mixture is forced from the space 10 into the cylinder spaces 8, 7. In a modification the passage 34 contains a non-return valve and a deflector passage is formed in the piston 6. The passage 29 may be external to the cylinders. In Fig. 4 the air and combustible mixture are fed through passages 27, 36 to chambers 44, 45 and their delivery into the pump spaces 9, 10 is controlled by valves 46, 47 actuated by a cam 50 on the crankshaft. The lower parts of the pistons 5, 6 acting as the scavenging air and charging pumps, may be of greater diameter than the working part of the pistons to produce supercharging. In Fig. 6, rich mixture fed to the space 9 is forced on the downstroke through a transfer passage 70 to the space 7 and compressed on the upstroke until a valve 64 opens, when the rich mixture is forced into air compressed in the cylinder 2 and spontaneously ignites. On the downstroke of piston 6, an exhaust port 66 is opened and scavenging air is forced from the space 10 through a transfer passage 71. In a modification the valve 64 is replaced by a slide valve and scavenging air is compressed in the space 9 and rich mixture in the space 10 which is connected by a transfer passage to the space 7. In a Diesel engine, Fig. 8, liquid fuel is injected into the cylinders 7, 8 through injectors 99, 100, fed by a pump 90 actuated by cylinder pressure acting through a passage 87 on a piston 92 connected to the pump plunger 93, the pistons 5, 6 both compressing scavenging air in the spaces 9, 10 on their downstrokes. The stroke of the pump 90 is controlled by an adjustable collar stop surrounding the plunger 93. The passage 87 may open into the top of cylinder 7 and may be kept clean by a pin on the piston 5. The pump 90 may comprise a diaphragm pump, or it may consist of a piston actuated by cylinder pressure and connected by a pivoted lever to a separate pump plunger- Diaphragm-actuated fuel pumps may alternatively be situated in the partitions 3, 4 and actuated by the pressure in the pump spaces 9, 10 to supply fuel to another set of  twin-cylinder, which in an engine with three sets of twin cylinders have a phase difference of 120 degrees. The Specification as open to inspection under Sect. 91 also describes an engine comprising two oppositely phased groups of twin cylinders which supply one another with combustible mixture. This subjectmatter does not appear in the Specification as accepted.