Patent GB-1443652-A (GB)
Title: Combination exhaust-gas cleaner and muffler for an automobile engine
IPC: B04C9/00
Filed: 1974-05-01
Abstract: 1443652 Centrifugal separators, treating I.C. engine exhaust gas NISSAN MOTOR CO Ltd 1 May 1974 [7 May 1973 18 June 1973] 19000/ 74 Headings B1W and B2P [Also in Divisions Fl] The invention relates to a combined exhaust gas cleaner and silencer for use in an exhaust system of an engine which incorporates a catalytic converter using a granular catalyst, and comprises an inlet tube 12 through which exhaust gases with entrained dust particles are passing. The apparatus comprises a casing 10 having end walls, the inlet tube 12 extending through one end wall, through a partition plate 26 and terminating in two outlets 14 which each enter tangentially the swirl tube 18 of a centrifugal separator. Any dust particles are flung outwardly and pass along 'the wall of the frusto-conical outlet 18b and are discharged into a dust-collecting chamber 36. The flow of cleaned exhaust gases reverses in direction to discharge through the outlet tube 20 into the expansion type silencer chamber 16; the tube 20 is open-ended and is formed with apertures 20b. The cleaned exhaust gases then pass through apertures 28 in the partition 26 to enter the exhaust outlet duct 32, the duct being formed with apertures 32a and extending through a partition 38 and the opposite end wall. The partition 38 defines with the partition 26 a resonance type silencer chamber 34 and with the end wall, the dust collection chamber 36. The apparatus shown in Figure 3 comprises an expansion type silencer chamber 44 and two centrifugal cleaning devices 48, each having an axial flow inlet with swirl vanes 52, a swirl chamber 50 from which dust particles are discharged into the dust collection chamber 60, and a cleaned gas outlet duct 54 from which the gases discharge into silencer chamber 62. The gases pass from the chaumber 62 through openings 64a in partition 64 into resonance chamber 66 discharging into the exhaust outlet duct 68 through apertures 68a. In Figure 4 not shown gases from the expansion chamber (74) enter the swirl tube (80) through swirl vanes (86), dust particles discharging from the swirl tube (80), the cleaned gases reverse in direction and flow through U-shaped outlet tubes (82) and duct (88) into the expansion/ resonance type silencer chamber (90); the gases finally enter the exhaust outlet duct (94) through apertures (96) for discharge to atmosphere. In Figure 5 gases from the inlet duct 12 enter chamber 108 passing through apertures 104a in partition 104 into chamber 110 which is filled with material 114 such as steel wool which it is stated acts to cause dust particles to agglomerate; the gases with entrained coarse particles then pass through apertures 106a in partition 106 into chamber 112 from which they discharge tangenitally into the swirl tube 18 of the centrifugal separator 16. Dust particles are discharged from swirl tube 18 into the collection chamber 116, and cleaned gas reverses in direction to flow through discharge tube 20; some gas passes through apertures 22 into chamber 120 then through the open end of outlet tube 124, while the remainder of the gas discharges from the tube 20 into the chamber 122, then through orifices 126 into the outlet tube 124. Further emibodiments are described, one of which is similar to Figure 3 but with a chamber filled with wire wool like chamber 110 of Figure 5: the other embodiment is similar to Figure 5 but having swirl vanes at the inlet of swirl chamber instead of tangential entry, and the chamber 120 is not provided.