Pollutant abatement system for gasoline vehicles
The present invention is directed to a pollutant abatement system for vehicles propelled by a gasoline combustion engine, in particular a gasoline direct injection engine (GDI). In addition, this invention is concerned with a process of mitigating noxious compounds in the exhaust of such an engine efficiently by applying the inventive abatement system to fulfill future legislative exhaust regulations.
1. Gasoline engine exhaust treatment system comprising a close-coupled three-way catalyst (TWC) and a downstream catalyzed gasoline wallflow particulate filter (GPF),
wherein an amount of platinum group metals in the TWC exceeds an amount of platinum group metals in the GPF by a factor of at least 5, and
wherein the platinum group metal loading of the TWC is from 25-120 g/ft 3 and the platinum group metal loading of the GPF is from 2-20 g/ft 3 .
2. Treatment system according to claim 1 , wherein the TWC and GPF each comprise the platinum group metals Pd and Rh.
3. Treatment system according to claim 1 , wherein the upstream TWC is located about 5-20 cm downstream of the engine outlet, manifold outlet or turbo charger.
4. Treatment system according to claim 1 , wherein the downstream GPF is located about 60-120 cm downstream of the engine.
5. Treatment system according to claim 1 , wherein a weight ratio of Pd to Rh in the TWC is 8-40:1.
6. Treatment system according to claim 1 , wherein a weight ratio of Pd to Rh in the GPF is 1-10:1.
7. Treatment system according to claim 1 , wherein the upstream TWC has a Pd-zoning.
8. Treatment system according to claim 1 , wherein the downstream GPF has a porous structure with a mean pore size of 14-25 μm.
9. Treatment system according to claim 8 , wherein a particle size of particles supporting the platinum group metals received by the GPF is less than the mean pore size of the GPF involved.
10. Treatment system according to claim 1 , wherein the downstream GPF has a porous structure with a porosity between 45%-75%.
11. Process for the abatement of noxious pollutants contained in an exhaust gas emitted by a gasoline engine, comprising contacting the exhaust gas with the system of claim 1 .
12. Treatment system according to claim 1 , wherein the amount of platinum group metals in the TWC exceeds the amount of platinum group metals in the GPF by a factor of 10-23.
13. Treatment system according to claim 1 , wherein the amount of platinum group metals in the TWC exceeds the amount of platinum group metals in the GPF by a factor of 15-20.
14. Treatment system according to claim 1 , wherein the amount of platinum group metals in the TWC exceeds the amount of platinum group metals in the GPF by a factor of 16-19.
15. Treatment system according to claim 1 , wherein the platinum group metal loading of the TWC is from 30-80 g/ft 3 .
16. Treatment system according to claim 1 , wherein the GPF has a platinum group metal loading that is arranged entirely or at least predominately within the porous walls of the GPF.
17. Treatment system according to claim 1 , wherein the platinum group metal loading of the GPF is from 2-15 g/ft 3 .
18. Treatment system according to claim 1 , wherein the platinum group metal loading of the GPF is from 2-10 g/ft 3 .
19. Treatment system according to claim 1 , wherein the GPF has a mean pore size of 18-22 μm and a porosity of 60-70%.