| 摘要 |
PROBLEM TO BE SOLVED: To satisfy limitations of exhaust pressure while suppressing boost pressure in a multistage supercharging system.SOLUTION: When a determination that exhaust pressure P4 is equal to or lower than a threshold value P4is made, feedback control for controlling an opening of a VN vane 24 is performed (Step S4). When a determination that the exhaust pressure P4 exceeds the threshold value P4is made, whether or not actual boost pressure exceeds a target boost pressure is determined to perform back pressure control (Step S5). When a determination that the actual boost pressure exceeds the target boost pressure is made, an opening of an exhaust control valve 9 is adjusted (Step S6). When a determination that the actual boost pressure is equal to or lower than the target boost pressure is made, the opening of the VN vane 24 is adjusted (Step S7).SELECTED DRAWING: Figure 4 |
