| 摘要 |
<p>PROBLEM TO BE SOLVED: To prevent the reduction in turbine efficiency by providing, on a turbine housing, a communicating passage so that the compressor rotor-side axial side walls of an inside scroll part and an outside scroll part communicate each other, and the inside scroll part-side opening is turned to an exhaust outlet. SOLUTION: When an internal combustion engine is operated, exhaust gas is carried into the turbine housing 12 of a variable capacity turbo charger to rotate a turbine rotor. In the low speed area of the internal combustion engine, an opening and closing valve provided on the inlet side of an outside scroll part 32 formed on the turbine housing 12 is closed to supply the exhaust gas to the turbine rotor only through an inside scroll part 31. Thus, high exhaust flow velocity can be provided to enhance the supercharging pressure. At this time, a communicating groove 11b is formed that the bearing housing-side axial side walls of the inside and outside scroll parts 31, 32 communicate each other, whereby the leakage of exhaust gas is prevented to suppress the reduction in turbine efficiency.</p> |
