| 摘要 |
PURPOSE:To improve drivability, by a method wherein a pair of exhaust turbochargers are provided, during high speed high load running, supercharging is effected in parallel by means of a pair of the turbochargers, and meanwhile, during low speed high load running and high speed middle load running, an engine is brought into a 2-stage supercharging state. CONSTITUTION:When an engine is in a low speed high load or a middle speed middle load running state, a switching valve body 14b of a switching device 14 is brought into a state A, and passages 23-25 are coupled to mating passages 10-13, 15 and 16. In this state, exhaust turbochargers 4 and 5 are connected in series, supercharging is effected in 2 stages to produce a given supercharging pressure. Meanwhile, during high speed high load running, the switching valve body 14b is moved axially to bring it into a state B, passages 26 and 27 are coupled to mating passages 10-13, 15 and 16. In this state, the exhaust turbochargers 4 and 5 are interconnected in series, parallel supercharging is effected, and the same high output as that of a conventional device can be produced. |
