| 摘要 |
PURPOSE:To enable to control the maximum supercharging pressure with ease and effectively in an apparatus comprising a plurality of turbochargers disposed in parallel with each other, by forming an intake-air relief passage by-passing all of blowers of each supercharger, and providing a supercharging pressure control valve in said intake- air relief passage. CONSTITUTION:A low-speed turbocharger 8 and a high-speed turbocharger 9 are constituted respectively by blowers 8a, 9a disposed in a first and a second branch intake passages 5, 6 formed in an intake passage 2 between an air-flow meter 4 and a throttle valve 7 in parallel with each other and turbines 8b, 9b disposed in a first and a second branch exhaust passages 10, 11 branched from an intermediate portion of an exhaust passage 3. In such an arrangement, an intake-air relief passage 21 is formed for communicating an intake passage 2d located on the downstream side of a joining portion 2a of the above two branch intake passages 5, 6 with an intake passage 2u located on the upstream side of the same. Further, a supercharging pressure control valve 22 is provided at an intermediate portion of the relief passage 21. With such an arrangement, the maximum supercharging pressure is limited by opening the control valve 22 when the supercharging pressure becomes higher than a prescribed value. |
