GB765948A - Multi-cylinder two-stroke internal combustion engines having exhaust gas turbo chargers - Google Patents

Abstract

765,948. Two-stroke engines ; charge pumps. SULZER FRERES SOC. ANON. March 15, 1955 [Dec. 17, 1954], No. 7589/55. Class 7 (2). To increase scavenging and charging, as at starting and low engine speeds, inlet passages 12 connecting piston-controlled inlet ports 2 of individual cylinders to a manifold 11 supplied with air by an exhaust-driven turbocharger have opening laterally thereto chambers 14 which are otherwise completely closed and the volume of which is varied by displacement pistons 16 whose frequency is the same as that of the working pistons 3. As shown, supplementary pistons 7 control exhaust ports 6 and the arrangement 11, 12, 14, 16 is duplicated on the other side of the engine. The pistons 16 lead the pistons 3 so as to build up pressure in the passages 12 before the ports 2 open and, to hinder back flow to the manifold 11 the portion of each passage 12 downstream of the chamber 14 may be enlarged, guide surfaces 20 may be used and/or check valves or venturi or spiral devices may be located in the passage 12 up-stream of the chamber 14. Modifications. In a double-acting loopscavenged engine, (Fig. 2) (not shown), chambers above and below the displacement pistons are respectively connected to passages from the manifold to upper and lower inlet ports. In Figs. 3 and 4 (not shown), singleacting engines, respectively loop-scavenged and uniflow-scavenged to cylinder-head exhaust valves, use the underside of the working pistons as displacement pistons working in a sub-chamber connected to the inlet passages via two further sub-chambers in series.