Patent ID: 7340888

Claim:
A diesel exhaust treatment system comprising: a first diesel particulate reduction device; a second diesel particulate reduction device, a volumetric weighted particle capture efficiency of the first diesel particulate reduction device and a volumetric weighted particle capture efficiency of the second diesel particulate reduction device each being in the range of 3 to 12.5; the first diesel particulate reduction device being positioned upstream from the second diesel particulate reduction device within the exhaust treatment system; the second diesel particulate reduction device having a higher particle capture efficiency than the first diesel particulate reduction device; the particle capture efficiency of the second diesel particulate reduction device being less than 50 percent; the first diesel particulate reduction device having a higher precious metal loading than the second diesel particulate reduction device; the second diesel particulate reduction device having a larger volume than the first diesel particulate reduction device; and the second diesel particulate reduction device having a larger volumetric weighted particle capture efficiency than the first diesel particulate reduction device.