| 摘要 |
The purpose of the present invention is to provide an engine (1) that enables a second turbocharger (10) to exhibit predetermined performance to the maximum without being affected by the operating environment of the engine (1). In the engine (1), a target turbocharger rotation speed (NTt1) is calculated, and the opening degree of a bypass valve (16) is changed on the basis of the difference between the actual turbocharger rotation speed (NT) and the target turbocharger rotation speed (NTt1) such that the actual turbocharger rotation speed (NT) is within a range of less than a predetermined value (α3) from the target turbocharger rotation speed (NTt1). This engine is configured so that: an increase rate (∆P) of an estimated compression-end pressure (P) in a cylinder caused by combustion of fuel is calculated on the basis of a fuel injection pressure (Pf) and fuel injection timing (θ); a correction coefficient (K) for the increase rate (∆P) of the estimated compression-end pressure (P) is calculated from the actual engine rotation speed (N) and a fuel injection amount (F); an estimated maximum compression-end pressure (Pmax) is calculated on the basis of the increase rate (∆P) of the estimated compression-end pressure (P) corrected by correction coefficient (K); and the target turbocharger rotation speed (NTt1) is reduced if the estimated maximum compression-end pressure (Pmax) is equal to a predetermined value (α2) or greater. |
