| 摘要 |
An i.c. engine, especially a diesel engine, has an intake manifold 26, an exhaust manifold 28, a turbocharger, eg a variable geometry turbocharger (VGT) 14, and an EGR system having a low pressure (LP) loop 13 on the low pressure side of the turbocharger 14 and a high pressure (HP) loop 12 on the high pressure side of the turbocharger 14. The LP an HP loops have respective EGR valves 76, 34. An ECU 24 may estimate and control flows in the HP loop 12 and LP loop 13 in response to signals from a first mass airflow sensor MAF1 upstream of the LP EGR entrance and a second mass airflow sensor MAF2 upstream of the HP EGR entrance and downstream of the LP EGR entrance. First and second throttle valves 78, 84 may be provided. Intake pressure sensors 96 and 50 may be provided upstream and downstream, respectively, of the HP EGR entrance. |
