GB1294792A - Exhaust noise muffler for an i.c. engine - Google Patents

Abstract

1294792 Exhaust silencers S Y RUBINSHTEIN M A BABIN A L GUTMAN V A PRESMAN M A RAZUMOVSKY and N G SHABUNYA 19 April 1971 [23 March 1970] 25358/71 Heading F1B Silencer for an I.C. engine comprises a shell partitioned into chambers and provided with gas inlet and outlet pipes, a perforated tube inside the shell and communicating with its chambers, at least two lateral baffles with inclined vanes formed in them, the baffles being rigidly secured at spaced apart positions inside the tube, so as to cause a rotary flow of the gases. The silencer shell 1 is made in pressed halves to which an inlet pipe 2 and an outlet pipe 3 are welded. A perforated tube 4 is connected to the inlet pipe and is supported in the shell by partitions 5 which form chambers 6,7 and 8. The downstream end of the tube 4 is spaced from the end of the outlet tube by a distance a, and is spaced from the end of the shell by a distance b to form a spark trap. Two lateral baffles 9 are fixed in the tube and each baffle is formed with a number of inclined vanes which give a rotary motion to the gas stream. The two baffles are angularly displaced relative to one another by an angle α, calculated from the expression α=<SP>#180xk</SP> n , where n=number of vanes and k= the overlap constant and has a value 0À3-1À0. When k=1À0, the maximum overlap prevails and the minimum straight-through gas flow is obtained. The distance between the baffles is greater than the diameter of the tube in order to minimise the resistance to flow. The vanes extend radially from a central sleeve 11 to the inner wall of the tube. In operation, burning particles which would appear in the exhaust gases as sparks are thrown outwardly by centrifugal force and pass through the perforations into chambers 7 and 6. Typically, for a 40-80 horsepower engine, the silencer has a volume of 7À5 litres and the vanes are inclined at 37 degrees to the baffles.