GB171115A - Improvements in internal combustion engines having scavenging and combustion air pumps - Google Patents

Abstract

171,115. Junkers, H. Nov. 8, 1920, [Convention date]. Two-stroke-cycle engines. -A pump piston, formed integral with or attached to one working piston, supplies scavenging air to a reservoir surrounding the cylinder and thence to the working cylinder. Engines are described in which two pistons reciprocate in opposite directions in the same cylinder. In Fig. 1, a piston 2 carries the pump piston 4, and scavenging air is compressed in the crank chamber 15 and transferred through valves 17 and ports 23 to the reservoir spaces 20, 24. Admission and exhaust ports 12, 13 are formed in the cylinder. In Fig. 2 the pistons are connected to the same crank shaft. The pump piston 4 is attached to the crosshead 7, which may work in slots in the cylinder wall at 1<1> to reduce the height of the engine. The air may be conveyed to the reservoir through a passage 18 or through valves in the piston as in Fig. 1. In a further modification, the piston rods 11 work in glands in the partition 22, the space 20 alone being used as the reservoir. Fuel is introduced at 14. The pistons are prevented from rotating by a recess in the scavenging piston engaging a projection on the casing. The baffles 22 tend to prevent loss of lubricating oil splashed by the cranks. In multicylinder engines, the reservoirs of the several engines may be interconnected to reduce the variations in pressure.