GB880380A - Improvements in or relating to internal combustion engines - Google Patents

Abstract

880,380. Gas-turbine plant. ARMSTRONG WHITWORTH & CO. (ENGINEERS) Ltd., Sir W. G. June 12, 1958 [July 2, 1957], No. 20887/57. Class 110 (3). [Also in Group XXVII] To enable an exhaust gas turbocharger 10, Fig. 1, to supply a sufficient air charge to a two-stroke engine cylinder 1 at all loads, the pressure pulses leaving the engine exhaust orifice 2 are divided into portions which travel different distances to the turbo charger 10 so that the pulses are in effect increased in frequency and diminished in amplitude. As shown, a branch exhaust passage 6 is provided, from the closed end 9 of which the pulses are reflected. The manner in which the invention also produces lowered pressure at the orifice 2 during scavenging and increased pressure at the instant of charging is described in detail. In Fig. 3 (not shown), an elongated branch passage connects to the turbo charger 10 independently of the main passage 5. In Fig. 9 (not shown), the turbo charger 10 is connected into a main dead-end exhaust passage close to the orifice 2. In Fig. 11, when one orifice 2 of a three-cylinder engine is open, the orifices of the other cylinders are closed and the duets 26 therefrom to a common exhaust passage 5b act as reflecting passages. A reflecting passage 35, Fig. 13, may surround the portion of the exhaust passage upstream (or downstream) of its junction therewith. Fig. 17 shows groups of three cylinders each connected to a common exhaust passage 5c by ducts 3b rendered of suitable length by having helical portions in a common pipe 3c. The invention is applicable to engines having piston controlled ports and to free piston and crank-shaft gas generators powering turbines. More than one exhaust system per cylinder may be provided.