Method of expecting n20 generation according to oxidation of nh3 in sdpf

Abstract

A method of expecting N 2 O generation according to oxidation of NH 3 in an SDPF according to an exemplary embodiment of the present invention may include measuring an initial NH 3 absorption amount in the SDPF, determining a first middle NH=3 absorption amount by subtracting an NH 3 slip amount in the SDPF from the initial NH 3 absorption amount in the SDPF, determining a second middle NH 3 absorption amount by subtracting an NH 3 amount oxidizing to NO x and N 2 from the first middle NH 3 absorption amount, determining N 2 O generation amount in the SDPF, and determining a final NH 3 absorption amount in the SDPF by subtracting the N 2 O generation amount from the second middle NH 3 absorption amount.

What is claimed is: 
     
         1 . Method of expecting N 2 O generation according to oxidation of NH 3  in a selective catalytic reduction on diesel particulate filer (SDPF), comprising:
 measuring an initial NH 3  absorption amount in the SDPF;   determining a first middle NH 3  absorption amount by subtracting an NH 3  slip amount in the SDPF from the initial NH 3  absorption amount in the SDPF;   determining a second middle NH 3  absorption amount by subtracting an NH 3  amount oxidizing to NO x  and N 2  from the first middle NH 3  absorption amount;   determining an N 2 O generation amount in the SDPF; and   determining a final NH 3  absorption amount in the SDPF by subtracting the N 2 O generation amount from the second middle NH 3  absorption amount.   
     
     
         2 . The method of  claim 1 , wherein
 in determining the first middle NH 3  absorption amount,   the NH 3  slip amount in the SDPF is a value determined by multiplying the initial NH 3  absorption amount and an NH 3  slip factor.   
     
     
         3 . The method of  claim 1 , wherein
 in determining the second middle NH 3  absorption amount,   the NH 3  amount oxidizing to NO x  and N 2  is a value determined by multiplying the first middle NH 3  absorption amount and an oxidation factor oxidizing to NO x  and N 2 .   
     
     
         4 . The method of  claim 1 , wherein
 in determining the N 2 O generation amount in the SDPF,   the N 2 O generation amount is a value determined by multiplying the second middle NH 3  absorption amount and an N 2 O generation factor.   
     
     
         5 . The method of  claim 4 , wherein
 the N 2 O generation factor is determined by considering a selective catalyst reduction (SCR) catalyst temperature, an NH 3  absorption ratio in the SDPF, an exhaust gas flow amount, an NO density, and a degree of catalyst degradation.   
     
     
         6 . The method of  claim 5 , wherein
 the SCR catalyst temperature is determined by measuring a exhaust gas temperature.   
     
     
         7 . The method of  claim 5 , wherein
 an NO gas amount is determined by measuring an NO density.   
     
     
         8 . The method of  claim 5 , wherein
 the degree of catalyst degradation is determined by a catalyst degradation map applying a catalyst degradation factor.   
     
     
         9 . The method of  claim 8 , wherein
 the N 2 O generation factor is determined by:   determining a first value by applying the SCR catalyst temperature and the NH 3  absorption ratio in the SDPF to a first map;   determining a second value by applying the exhaust gas flow amount and the NO density to a second map;   determining a third value by applying the catalyst degradation factor to a third map; and   multiplying the first value, the second value, and the third value together.   
     
     
         10 . The method of  claim 1 , further including:
 determining an N 2 O slip amount by applying a transform constant using a map to the N 2 O generation amount; and   determining an NH 3  slip amount by subtracting the NO 2  generation amount from the initial NH 3  absorption amount in the SDPF.