| 摘要 |
PURPOSE:To obtain good turbocharging response by causing the rotation of a downstream turbine preliminarily on an exhaust after its actuation of an upstream turbine, and increasing the turbine speed through throttling an exhaust introduced to the downstream turbine at the start of acceleration. CONSTITUTION:Turbines 9a and 10a each for two turbochargers 9 and 10 are arranged in series in the exhaust passage 11 of an engine. And a passage 12 is branched from the exhaust passage 11 at the upstream of a primary turbine 9a, continuously to the upstream of a secondary turbine 10a, and a flow control valve 13 is provided in way of the said passage 12. On the other hand, a variable capacity mechanism 18 is provided for the secondary turbine 10a and so made that a variable vane 20 will throttle the throat of a scroll housing 19, depending upon pressure working on a diaphragm device 21 via a pressure regulating valve 22. And pressure regulating valves 17 and 22 are actuated by a control circuit 29, according to detected signals from a speed sensor 27 and a turbocharged pressure sensor 28, thereby controlling the opening of the flow control valve 13 and the variable vane 20. |
