| 摘要 |
PURPOSE:To make adequate fault diagnosis of all valves on the side of a secon dary turbo supercharger and if any fault is found, fail-safe system is operated appropriately. CONSTITUTION:A primary turbo supercharger 40 and a secondary turbo supercharger 50 are arranged in parallel to each other in the intake and the exhaust system of an engine body, a supercharge pressure relief valve 60, an intake control valve 58 and an exhaust control valve 55 are provided on the side of a secondary turbo supercharger, only the primary turbosupercharger 40 is operated in the single-turbo mode, the secondary turbo supercharger 50 is preliminarily rotated in the pre-rotational mode, and the primary turbo supercharger 40 and the secondary turbo supercharger 50 are controlled to operate together in the twin turbo mode. Furthermore, whether any one of the supercharge pressure valve 60, the intake control valve 58 and the exhaust control valve 55 is faulty or not is diagnosed by the differential pressure DELTAPdi between pressure present upstream and downstream of the intake control valve 58 for each of single-turbo mode, prerotational mode and twin turbo mode. |
