GB675500A - Improvements relating to multi-cylinder two-stroke internal combustion engines - Google Patents

Abstract

675,500. Engine construction; pumps. SULZER FRERES SOC. ANON. May 19, 1950 [Jan. 14, 1950], No. 12652/50. Class 7(ii) In a multi-cylinder two-stroke engine of the kind having a crosshead and provided with scavenging pumps mounted at the side of the engine, at least two scavenging pump casings are integral with or rigidly secured to an engine structure reinforcing member lying generally parallel to the engine crankshaft and itself rigidly secured to a portion of the engine framework which accommodates the crosshead slideways of at least two working cylinders. The reinforecing member may be a box-like structure 8, Figs. 2 and 3, unitary with the casings of the scavenging pumps 6, the surface of the member 8 which lies against the engine framework 7 forming slideways 9 for the crosshead slides 10, from which the pumps 6 are operated through arms 14 integral with or bolted or welded to the slides. Shims 13 allow true alignment of the piston rod 27, the slide 10 being located against the slideways 9 by guide rails 12. The pumps 6 force air sucked through inlets 17 in the member 8 to a receiver 20 which delivers to the working cylinders 21 through ports 22 which are accessible for cleaning either from the receiver 20 itself or through an opening having a cover 24 and which also serves for pump piston removal. Dirt from the ports 22 dislodged inwardly on cleaning is caught by a partition 28 accessible through a door 29. In Fig. 4. (not shown) the member 8 is built up of separate box-like members, each integral with and enclosing a single pump casing, joined as by bolting; slideways separate from the box-like members are provided which, together with the guide rails, are made hollow for the circulation of coolant liquid. The reinforcing member may be in the form of a single plate 33, Fig. 5, or a number of individual plates joined as by bolting, to which the scavenging pump cylinders 6 are bolted; cast or welded. In Fig. 6 (not shown), the cylinders are welded to the periphery of bores, slots or other shaped perforations in a plate. Alternatively, the reinforcing member may consist of a number of separated plates 37, Fig. 8, bridged by cylinders 6 welded or bolted thereto. In Fig. 12, scavenging pump cylinders 51 integral with a reinforcing member 52 have pistons 53 actuated from the crossheads 54 through links 55 and levers 56, oil for lubricating the linkage 55. 56 and for cooling and lubricating the main engine reciprocating parts being supplied from, and in some cases returned to, the stationary .bearing 57 through passages in the linkage. In Fig. 13 (not'shown) is a a similar arrangement using oscillating vane scavenging pumps, and the invention is also applicable to rotary scavenging pumps such as Roots blowers. Fig 11 (not shown) discloses an arrangement differing from that of Figs. 2 and 3 in having an engine framework welded-up from simple sections, with cross-head guides passing between each pair of working cylinders, the reinforcing member being a box structure fabricated by welding suitable plates and bars to the scavenging pump cylinders, and secured to the cross-head guides as by bolting. In all cases, the reinforcing member may carry all the scavenging pump casings, when it may extend over all or part of the engine length, or only some of the total number of casings. Two or more sets, each consisting of two or more casings and a reinforcing member, may be employed, when each set may bridge the space between two adjacent columns of the engine frame. Individual reinforcing members may be either independent or joined. The scavenging air receiver may be common to all the working cylinders, and may be separate from the scavenging pumps and connected thereto by pipes.