| 摘要 |
If the exothermic activity of the catalyst exceeds a safety threshold value during application of a second, higher temperature regeneration strategy, the fuel feed is controlled to reduce it progressively; if it is above the threshold after a first period the feed switches to a first strategy and if it is still above the threshold after a second period the regeneration is stopped. - System for helping the regeneration of means of depollution (1) associated with an oxidation catalyst (2) and integrated into the exhaust pipe (3) of a vehicle's Diesel engine (4). The engine is connected to a common fuel feed injecting fuel into all the cylinders, in the manner of a post-injection. At least two regeneration strategies are put into operation by isocouple at a first and second level (10, 11) depending on the different engine operating control parameters to obtain different heat levels in the exhaust pipe. The heat level corresponding to the second level strategy (10) is greater than that of the first level strategy (11). The fuel feed is designed to operate two successive post-injections. During regulation, the fuel feed is designed to progressively reduce the flow of fuel in the second injection using a correction factor between 0 and 1 determined from the gap between the exothermic level (NT) and the safety threshold value (seuil-secu) by a non-linear gain PI regulator. The means of recording the exothermic level are two temperature detectors (9a, 9b) upstream and downstream of the catalyst. The engine is a diesel engine associated with a turbocompressor. The threshold safety value can be calibrated. The means of depollution include a particle filter and/or NOx trap and/or SOx trap and/or oxidation catalyst. The fuel includes an additive designed to be deposited onto the means of depollution with the particles with which it is mixed to aid regeneration, or an additive which forms a NOx trap. |
