| 摘要 |
A method of operating a low pressure EGR valve (610, fig.3) in a low pressure EGR route (600) of an i.c. engine (110) equipped with an aftertreatment system comprising an urea injector upstream of a Selective Catalytic Reduction on Filter (SCRF) (500) comprises the steps of performing a regeneration procedure of the SCRF; monitoring during the regeneration procedure of the SCRF an enabling condition for opening the EGR valve (step720); and, if the enabling condition is satisfied, opening the low pressure EGR valve (step 750), wherein the enabling condition is satisfied if an urea injection is not performed. Alternatively, the enabling condition may be that engine speed and engine load are greater than respective threshold values. The EGR valve may be opened and closed intermittently. The EGR valve may be opened for a period of time that is a function of SCRF inlet temperature. |
