| 摘要 |
An EGR fault in an engine is detected by comparing actual MAP values with inferred MAP values, the latter being based on MAF and engine speed. Multiple pairs of inferred and actual MAP, some having low EGR and other having high EGR rate. The two values are expected to deviate at high EGR rate and to be nearly equal at low EGR rate. If no such deviation at high EGR, then a fault is determined. According to the present disclosure, the computation of inferred MAP includes a compensation for flow into the intake through a carbon canister system. Without such compensation, the EGR routine is applied to situations without flow from the canister. Such a limitation caused a problem in HEV vehicles, in which engine operating time is less than typical engine installations. Additionally, the confounding effects of rapid VVT movement are excluded from the computations. |
