GB186292A - Improvements in starting and reversing compound internal combustion engines - Google Patents

Abstract

186,292. Sperry, E. A. March 16, 1921. starting.- In starting a compound four-stroke engine having two high pressure cylinders and a . ccmmon low - pressure cylinder by admitting air or gas under pressure to the high-pressure cylinders, the induction valves are held open, the transfer valves are actuated substantially as in the combustion cycle, and the closing of the exhaust valve is delayed so that two-stroke working is secured. In the engine shown, compressed air for starting is taken through a pipe 27 from a reservoir 150 which normally supplies air to the high-pressure cylinders, the air being compressed by the underside of the low pressure piston 7 past a valve 14. A combined inlet and transfer valve 17, 19 between the high pressure and low-pressure cylinders 3, 4 is of the kind described in Specification 186,291, [Class 7 (vi), Internal combustion engines, Valves &c. for]. At starting, the inlet valve 19 is held open by a rod 100<1> engaging the valvelever 29<1>, Fig. 5, and the exhaust valve 106 is opened later than in normal running by a rod 139<1>, Fig. 6, connected by a lever to an eccentric pivot for the exhaust-valve lever. The exhaust valve is also held open until the end of the inlet stroke of the low-pressure piston, by an additional cam moved axially on its shaft 40 by means of a rod 108. The inlet valve 110<1> in the pump space below the piston 7, Fig. 4, is held open by a rod 114' acting upon a spring arm 113' on a lever 111<1>, The fuel-injection valve is closed by a rod 139 connected to the valve lever 53, Fig. 7. by a bell-crank lever 117 pivoted at 118. A finger 120 on the lever 117 actuates a lever which closes an ignition circuit when the fuel valve is returned to the active position. The adjustments are effected from a single cam 126, Fig. 6, turned by means of a handle 129 acting directly or through a pinion 128. The cam has a spiral slot 130 in which engage rollers 131, 132 on arms 133, 134 connected to the adjusting-rods 100<1> &c. In position c of the handle 129, all the engine cylinders are supplied with compressed air for starting; in position b, one high-pressure cylinder is started on fuel; and in position a, all the cylinders are working normally on fuel. Reversing is effected 'by slowing down, reversing the direction of rotation of the cam shaft, and starting in the reverse direction by the method described. The cam shaft is driven by means of bevel gearing and a sliding clutch, the teeth of which engage only in certain positions. The shifting lever for the clutch is controlled by a locking plate connected to a governor so that it can only be moved when the engine is slowed down. Specifications 154,640 and 186,357, [both in Class 7 (ii), Internal-combustion engines, Arrangement. &c. of], also are referred to.