ACTIVE HYDROCARBON TRAP FOR REDUCTION OF EMISSIONS FROM INTERNAL COMBUSTION ENGINES USING A TWO-VALVE CONFIGURATION
A device for reducing emissions from an internal combustion engine having a close-coupled catalyst including an underbody catalyst and a hydrocarbon trap disposed downstream of the close-coupled catalyst. The device includes a heat exchanger and a liquid water knockout disposed downstream of the close-coupled catalyst. The device includes a two-valve system configured to dynamically adjust a flow path of exhaust from the internal combustion engine through the underbody catalyst, hydrocarbon trap, or both, to reduce emissions. A method for reducing emissions including feeding an exhaust gas from the internal combustion engine to the close-coupled catalyst, producing a catalyzed exhaust gas. The method includes flowing the catalyzed exhaust gas from the close-coupled catalyst to the two-valve system.
1 . A device for reducing emissions from an internal combustion engine having a close-coupled catalyst, the device comprising:
a hydrocarbon trap disposed downstream of the close-coupled catalyst;
an underbody catalyst disposed downstream of the hydrocarbon trap;
and
a two-valve system configured to dynamically adjust a flow path of exhaust from the internal combustion engine through the underbody catalyst or the underbody catalyst and the hydrocarbon trap, to reduce emissions, comprising:
a first flow line from a close-coupled catalyst to the hydrocarbon trap;
a second flow line from the hydrocarbon trap to the underbody catalyst with a first valve disposed in the second flow line;
a third flow line from the close-coupled catalyst to the underbody catalyst with a second valve disposed in the third flow line;
a fourth flow line from the underbody catalyst to an ambient environment; and
a control system, configured to:
open the first valve open and close the second valve during a first period of time corresponding to a flow through condition having a temperature less than 125° C.;
open the second valve and close the first valve during a second period of time corresponding to a bypass condition having a temperature in a range of 125 to 350° C.
2 . (canceled)
3 . (canceled)
4 . (canceled)
5 . The device of claim 1 , wherein the underbody catalyst is separate from the hydrocarbon trap.
6 . (canceled)
7 . The device of claim 1 , wherein the hydrocarbon trap contains a sorbent material, further comprising a zeolite or activated carbon.
8 . The device of claim 7 , wherein the sorbent material is pelletized or wash-coated onto a honeycomb-like structure.
9 . A method for reducing emissions from an internal combustion engine having a close-coupled catalyst, using a system comprising:
an underbody catalyst disposed downstream of the close-coupled catalyst;
a hydrocarbon trap disposed downstream of the close-coupled catalyst;
and
a two-valve system to optimize performance of the underbody catalyst and the hydrocarbon trap, wherein the two-valve system comprises:
a first flow line from a close-coupled catalyst to the hydrocarbon trap;
a second flow line from the hydrocarbon trap to the underbody catalyst with a first valve disposed in the second flow line;
a third flow line from the close-coupled catalyst to the underbody catalyst with a second valve disposed in the third flow line; and
a fourth flow line from the underbody catalyst to an ambient environment.
the method comprising:
feeding an exhaust gas from the internal combustion engine to the close-coupled catalyst, producing a catalyzed exhaust gas;
flowing the catalyzed exhaust gas exiting the close-coupled catalyst to the two-valve system;
during a first period of time corresponding to the flow through condition having a temperature less than 125° C.:
opening the first valve;
closing the second valve;
flowing a hydrocarbon trap effluent from the hydrocarbon trap to the underbody catalyst through the first valve, producing a first underbody catalyst effluent; and
ejecting the first underbody catalyst effluent from the underbody catalyst to the ambient environment;
during a second period of time corresponding to a bypass condition having a temperature in a range of 125 to 350° C.:
closing the first valve;
opening the second valve;
flowing the catalyzed exhaust gas from the close-coupled catalyst to the underbody catalyst through the second valve, producing a second underbody catalyst effluent; and
ejecting the second underbody catalyst effluent to the ambient environment.
10 . (canceled)
11 . (canceled)
12 . The method of claim 9 , wherein the exhaust gas has a temperature below 125° C. during the first period of time corresponding to the flow through condition.
13 . The method of claim 9 , wherein the exhaust gas has a temperature in a range of 125 to 350° C. during the second period of time corresponding to the bypass condition.