Coolant heating method for releasing reductant

Abstract

A system and method for heating main unit containing host salt having ammonia that is used as reductant in an engine exhaust gas after-treatment system. Engine coolant is delivered from internal combustion engine to auxiliary heating device. When necessary, the auxiliary heating device heats the engine coolant to temperatures that will aid in releasing ammonia from the host salt. The auxiliary heating device may employ an electric heating element, a combustion element, or be an exhaust gas heat exchanger, among other heating methods. The heated engine coolant is delivered to a coolant heating manifold, where heat from the heated coolant is transferred to the main unit. The transferred heat may aid in elevating the temperature in/of the main unit to facilitate the release of stored ammonia from the host salt as a gaseous reductant. The gaseous ammonia may then flow from the main unit.

1 . A method for heating a main unit containing a host salt having ammonia comprising:
 delivering an engine coolant to an auxiliary heating device;   heating the delivered engine coolant in the auxiliary heating device when the delivered engine coolant is below a predetermined temperature; and   transferring heat from the heated engine coolant to the main unit to aid in the release of an ammonia gas from the host salt.   
     
     
         2 . The method of  claim 1 , wherein the step of heating the delivered engine coolant includes supplying an electrical current to an electric heating element of the auxiliary heating device. 
     
     
         3 . The method of  claim 2 , wherein at least a portion of the electric heating element is submersed in at least a portion of the engine coolant being delivered to the auxiliary heating device. 
     
     
         4 . The method of  claim 2 , further including the step of controlling when electrical current is to be supplied to the electric heating element. 
     
     
         5 . The method of  claim 4 , further including the step of sensing the temperature of the delivered engine coolant. 
     
     
         6 . The method of  claim 1 , wherein the step of heating the engine coolant includes combusting a fuel supplied to the auxiliary heating device, the combustion of the fuel being used to heat the engine coolant delivered to the auxiliary device. 
     
     
         7 . The method of  claim 1 , further including the step of transferring heat from a heated engine exhaust gas to the engine coolant in the auxiliary heating device. 
     
     
         8 . A method for heating a main unit containing a host salt having ammonia comprising:
 delivering an engine coolant from an engine to an auxiliary heating device through a coolant supply line;   heating the delivered engine coolant in the auxiliary heating device when the delivered engine coolant is below a predetermined temperature;   supplying the heated engine coolant from the auxiliary heating device to a coolant heating manifold through a heated coolant supply line; and   transferring heat from the heated engine coolant in the coolant heating mantle to the main unit to aid in the release of an ammonia gas from the host salt.   
     
     
         9 . The method of  claim 8 , wherein the step of heating the engine coolant includes supplying an electrical current to an electric heating element of the auxiliary heating device. 
     
     
         10 . The method of  claim 8 , wherein the step of heating the delivered engine coolant includes combusting a fuel supplied to the auxiliary heating device, the combustion of the fuel being used to heat the engine coolant delivered to the auxiliary device. 
     
     
         11 . The method of  claim 8 , further including the step of sensing the temperature of the engine coolant. 
     
     
         12 . A system for heating coolant from an engine to provide heat to assist in the release a gaseous ammonia reductant from a host salt, the system comprising:
 an auxiliary heating device having a coolant inlet, a coolant outlet, and a passageway, the auxiliary heating device configured to receive engine coolant from the engine, the auxiliary heating device configured to heat engine coolant that flows through the passageway;   a coolant heating mantle configured to receive heated coolant from the auxiliary heating device; and   a main unit, the main unit configured to contain the host salt, at least a portion of the main unit being surrounded by the coolant heating mantle, the coolant heating mantle configured to transmit heat from heated coolant flowing through the coolant heating mantle to the main unit to increase the temperature of the main unit to a temperature that promotes the release of the gaseous ammonia reductant from the host salt.   
     
     
         13 . The system of  claim 12 , wherein the auxiliary heating device is an electric coolant heater, the electric coolant heater having a heating element that is configured to heat the received engine coolant. 
     
     
         14 . The system of  claim 12 , wherein the auxiliary heating device is a fuel fired heater having a combustion element that is configured to combust fuel that is delivered to the fuel fired heater, the combusted fuel providing heat that is used to heat the engine coolant. 
     
     
         15 . The system of  claim 12 , wherein the auxiliary heating device is an exhaust gas heat exchanger having an exhaust gas inlet in fluid communication with an exhaust gas outlet by an exhaust gas line, at least a portion of the exhaust gas line positioned within the passageway, the auxiliary heating device being configured for exhaust gas from the engine to flow through the exhaust gas line.