| 摘要 |
PURPOSE:To prevent leakage of lubricating oil toward the side of turbines which have rotational sliding parts using no mechanical seal, by providing an oil control valve in a lubricating-oil passage for a subsidiary supercharger, and reducing the quantity of lubricating oil supplied to the subsidiary supercharger when operation of the subsidiary supercharger is stopped or it is turned at a low speed. CONSTITUTION:At the time of low-speed operation of an internal-combustion engine, an oil control valve 31 is turned OFF by a signal from a control unit 37, so that an opening 41 of a sleeve-like member 35 is closed by a valve body 39 of the control valve 31. In this state, lubricating oil is carried to a rotational sliding part 25b through a small hole 33 of the sleeve-like member 35 and a lubricating-oil passage 23b although the quantity of lubricaing oil supplied under pressure is small. As the engine speed is raised gradually, the turning speed of a turbine 3a of a main supercharger 1a and that of a turbine 3b of a subsidiary superchager 1b are also raised. Further, with increasing of the engine speed and the turning speed of the superchargers, the oil control valve 31 is turned ON by the signal given from the control unit 37, so that the opening 41 of the sleeve member 35 is opened by the valve body 39. |
