| 摘要 |
PURPOSE:To enable the heat of a supercharged air passage to be shielded for preventing it from being transmitted to an air introducing passage by arranging a relief passage for relieving excess air between the air introducing passage and the supercharged air passage. CONSTITUTION:In a low speed region in which only a primary-side turbosupercharger 9 is operated, since excess air is not relieved, air does not flow inside a relief passage 22, and the temperature of the relief passage 22 becomes low. Since the relief passage 22 is arranged between the air introducing passage 3b1 of a secondary-side turbosupercharger 10 and a supercharged air passage 3b2, the heat of the supercharged air passage 3b2 is shielded by the relief passage 22 so as not to be transmitted to the air introducing passage 3b1. Thus, the density of air in the air introducing passage 3b1 is heightened, and supercharging efficiency is enhanced. |
