STRUCTURE OF FIXING TURBINE HOUSING IN DUAL TURBO-SUPERCHARGER SYSTEM

A dual turbo-supercharger system comprises an exhaust passage (14) having a first exhaust discharge port (55) and a second exhaust discharge port (56), a first turbine housing (24) for containing a first turbine (22), a second turbine housing (34) for containing a second turbine (32), and a fastening tool (63). The exhaust passage (14) is provided with a first branch pipe portion (53) and a second branch pipe portion (54) branched from a section (52) for collecting exhaust gas of an exhaust manifold (50), and the first exhaust discharge port (55) and the second exhaust discharge port (56) are located at the downstream ends thereof. The first turbine housing (24) has a first flange (27) around a first exhaust inlet (25), and the second turbine housing (34) has a second flange (37) around a second exhaust inlet (35). The fastening tool (63) consists of a bolt (64) and a nut (65) which fasten both flanges (27, 37) under a state where the first exhaust inlet (25) is brought close to the first exhaust discharge port (55) and the second exhaust inlet (35) is brought close to the second exhaust discharge port (56).