Exhaust gas treatment system having a solid ammonia gas producing material

Abstract

An exhaust gas treatment system for an internal combustion engine is provided, including an exhaust gas conduit, a pressurized vessel, a selective catalytic reduction (“SCR”) device, and a control module. The internal combustion engine has a plurality of pistons and an engine off condition that indicates that the pistons are generally stationary. The exhaust gas conduit is in fluid communication with, and configured to receive an exhaust gas from the internal combustion engine. The pressurized vessel stores a solid ammonia gas producing material. The pressurized vessel is selectively activated to heat the solid ammonia gas producing material into an ammonia gas. The ammonia gas is released into the exhaust gas conduit. The SCR device is in fluid communication with the exhaust gas conduit and is configured to receive the ammonia gas.

What is claimed is: 
     
         1 . An exhaust gas treatment system for an internal combustion engine, the internal combustion engine having a plurality of pistons and an engine off condition that indicates that the plurality of pistons are generally stationary, comprising:
 an exhaust gas conduit in fluid communication with, and configured to receive an exhaust gas from the internal combustion engine during operation;   a pressurized vessel storing a solid ammonia gas producing material, the pressurized vessel selectively activated to heat the solid ammonia gas producing material into an ammonia gas, the ammonia gas being released into the exhaust gas conduit;   a selective catalytic reduction (“SCR”) device in fluid communication with the exhaust gas conduit and configured to receive the ammonia gas, the SCR device having a SCR temperature profile and a SCR light-off temperature;   a control module in communication with the internal combustion engine and the pressurized vessel, the control module receiving a signal indicating the engine off condition, the control module including a memory for storing a value indicating a target amount of the ammonia gas released into the exhaust gas conduit by the pressurized vessel and loaded on the SCR device, the control module comprising:
 a control logic for determining if the internal combustion engine is in the engine off condition based on the signal; 
 a control logic for determining the SCR temperature profile; 
 a control logic for determining if the SCR temperature profile is below a threshold value if the internal combustion engine is in the engine off condition, the threshold value indicating that the SCR device is a specified amount below the SCR light-off temperature; 
 a control logic for determining if the pressurized vessel has released the target amount of the ammonia gas into the exhaust gas conduit if the SCR temperature profile is below the threshold value; and 
 a control logic for deactivating the pressurized vessel if the pressurized vessel has released the target amount of the ammonia gas. 
   
     
     
         2 . The exhaust gas treatment system of  claim 1 , wherein the control module includes control logic for monitoring a pressure transducer that indicates pressure located internally of the pressure vessel, and wherein the pressure vessel internally attains a threshold pressure. 
     
     
         3 . The exhaust gas treatment system of  claim 2 , wherein the control module includes control logic for activating the pressurized vessel if the threshold pressure is attained, and if the pressurized vessel has not released the target amount of the ammonia gas into the exhaust gas conduit. 
     
     
         4 . The exhaust gas treatment system of  claim 2 , wherein the threshold pressure creates the gas propagation required for creating a gas propagation needed to create the target amount of ammonia gas released into the exhaust gas conduit that is loaded on the SCR device. 
     
     
         5 . The exhaust gas treatment system of  claim 1 , wherein the target amount of ammonia gas is an amount needed to create a saturation amount of ammonia gas that is stored by the SCR device, and wherein the saturation amount represents a maximum amount of ammonia gas the SCR device is capable of storing. 
     
     
         6 . The exhaust gas treatment system of  claim 1 , further comprising an electrically heated catalyst (“EHC”) device in fluid communication with the exhaust gas conduit and configured to receive the exhaust gas during operation of the internal combustion engine, and selectively activated to produce heat and induce oxidation of the exhaust gas, the EHC device having an oxidation catalyst compound disposed thereon for converting nitrogen oxide (“NO”) to nitrogen dioxide (“NO 2 ”). 
     
     
         7 . The exhaust gas treatment system of  claim 6 , further comprising an oxidation catalyst (“OC”) device in fluid communication with the exhaust gas conduit, the OC device having a front face, the OC device adsorbing hydrocarbons and selectively activated to induce oxidation of the hydrocarbons in the exhaust gas during operation of the internal combustion engine, wherein the EHC device is located within the OC device. 
     
     
         8 . The exhaust gas treatment system of  claim 7 , wherein at least one of the EHC device and the OC device has an oxidation catalyst compound disposed thereon that is one of Palladium (“Pd”), Platinum (“Pt”), and perovskite. 
     
     
         9 . The exhaust gas treatment system of  claim 7 , wherein the control module includes control logic for selectively activating the EHC depending on if the SCR device has achieved the light-off temperature during operation of the internal combustion engine. 
     
     
         10 . The exhaust gas treatment system of  claim 1 , further comprising a first temperature sensor and a second temperature sensor in fluid communication with the exhaust gas conduit, the first temperature sensor situated upstream of the SCR device and the second temperature sensor situated downstream of the SCR device. 
     
     
         11 . The exhaust gas treatment system of  claim 10 , wherein the control module includes control logic for monitoring the first temperature sensor and the second temperature sensor, and a control logic for calculating the SCR temperature profile based on signals from the first temperature sensor and the second temperature sensor. 
     
     
         12 . The exhaust gas treatment system of  claim 1 , further comprising an ignition switch, wherein the ignition switch sends the signal to the control module that is indicative of the engine off condition. 
     
     
         13 . An exhaust gas treatment system for an internal combustion engine, the internal combustion engine having a plurality of pistons and an engine off condition that indicates that the plurality of pistons are generally stationary, comprising:
 an exhaust gas conduit in fluid communication with, and configured to receive an exhaust gas from the internal combustion engine during operation;   a pressurized vessel storing a solid ammonia gas producing material, the pressurized vessel selectively activated to heat the solid ammonia gas producing material into an ammonia gas, the ammonia gas being released into the exhaust gas conduit, the pressure vessel configured for internally attaining a threshold pressure;   a pressure transducer that indicates pressure located internally of the pressure vessel;   a SCR device in fluid communication with the exhaust gas conduit and configured to receive the ammonia gas, the SCR device having a SCR temperature profile and a SCR light-off temperature;   an ignition switch that sends a signal that is indicative of the engine off condition; and   a control module in communication with the internal combustion engine, the pressurized vessel, the pressure transducer, and the ignition switch, the control module including a memory for storing a value indicating a target amount of the ammonia gas released into the exhaust gas conduit by the pressurized vessel and loaded on the SCR device, the control module comprising:
 a control logic for monitoring the ignition switch for the signal, wherein the control module includes control logic for determining if the internal combustion engine is in the engine off condition based on the signal; 
 a control logic for determining the SCR temperature profile; 
 a control logic for determining if the SCR temperature profile is below a threshold value if the internal combustion engine is in the engine off condition, the threshold value indicating that the SCR device is a specified amount below the SCR light-off temperature; 
 a control logic for determining if the pressurized vessel has released the target amount of the ammonia gas into the exhaust gas conduit if the SCR temperature profile is below the threshold value; 
 a control logic for deactivating the pressurized vessel if the pressurized vessel has released the target amount of the ammonia gas; 
 a control logic for monitoring the pressure transducer for pressure located internally of the pressure vessel; and 
 a control logic for activating the pressurized vessel if the threshold pressure is attained, and if the pressurized vessel has not released the target amount of the ammonia gas into the exhaust gas conduit. 
   
     
     
         14 . The exhaust gas treatment system of  claim 13 , wherein the threshold pressure creates the gas propagation required for creating a gas propagation needed to create the target amount of ammonia gas released into the exhaust gas conduit that is loaded on the SCR device. 
     
     
         15 . The exhaust gas treatment system of  claim 13 , wherein the target amount of ammonia gas is an amount needed to create a saturation amount of ammonia gas that is stored by the SCR device, and wherein the saturation amount represents a maximum amount of ammonia gas the SCR device is capable of storing. 
     
     
         16 . The exhaust gas treatment system of  claim 13 , further comprising an EHC device in fluid communication with the exhaust gas conduit and configured to receive the exhaust gas, and selectively activated to produce heat and induce oxidation of the exhaust gas during operation of the internal combustion engine, the EHC device having an oxidation catalyst compound disposed thereon for converting nitrogen oxide NO to nitrogen dioxide NO 2 . 
     
     
         17 . The exhaust gas treatment system of  claim 16 , further comprising an OC device in fluid communication with the exhaust gas conduit, the OC device having a front face, the OC device adsorbing hydrocarbons and selectively activated to induce oxidation of the hydrocarbons in the exhaust gas during operation of the internal combustion engine, wherein the EHC device is located within the OC device. 
     
     
         18 . The exhaust gas treatment system of  claim 17 , wherein at least one of the EHC device and the OC device has an oxidation catalyst compound disposed thereon that is one of Palladium Pd, Platinum Pt, and perovskite. 
     
     
         19 . The exhaust gas treatment system of  claim 13 , further comprising a first temperature sensor and a second temperature sensor in fluid communication with the exhaust gas conduit, the first temperature sensor situated upstream of the SCR device and the second temperature sensor situated downstream of the SCR device. 
     
     
         20 . The exhaust gas treatment system of  claim 19 , wherein the control module includes control logic for monitoring the first temperature sensor and the second temperature sensor, and a control logic for calculating the SCR temperature profile based on signals from the first temperature sensor and the second temperature sensor.