DEVICE FOR ESTIMATING PM ACCUMULATION QUANTITY IN DPF

摘要

PROBLEM TO BE SOLVED: To provide a device for estimating a PM accumulation quantity in DPF (7), the device being capable of estimating the PM accumulation quantity more accurately than a conventional device even if a malfunction is found in a charge flow meter (31).SOLUTION: The device for estimating the PM accumulation quantity in the DPF has an exhaust quantity computation means (51) for computing a quantity of PM exhaust which is discharged in an exhaust gas path (3), and a naturally regenerated quantity computation means (52) for computing a quantity of PM regeneration which is naturally regenerated in the DPF (7), and is configured to estimate the PM accumulation quantity in the DPF (7) from the difference between the PM exhaust quantity which is computed by the exhaust quantity computation means (51) and the PM regeneration quantity which is computed by the naturally regenerated quantity computation means (52) in a PM accumulation quantity estimation means (50). Moreover, the device is configured such that, if a malfunction is found in the charge flow meter (31), the PM regeneration quantity by nitrogen dioxide is computed, and the PM accumulation quantity in the DPF is estimated, without using the charge flow measured by the charge flow meter (31).