Controlled catalytic converter heating

Abstract

The rate at which a catalytic converter for an internal combustion engine heats up to its normal operating temperature range can be increased by applying an electrical load that is powered by the internal combustion engine. Applying the electrical load demands more power from the engine which therefore has to work harder to maintain a given engine speed. The internal combustion engine then generates more heat that can be used to reduce the time to bring the catalytic converter up to its working temperature. The electrical load can be a catalytic converter heater to further reduce the time to bring the catalytic converter up to its working temperature. The result is a reduction in emissions.

1 . A method of operating an engine system, the engine system including an internal combustion engine that is operable to apply drive to a drive train, a catalytic converter through which exhaust gases from the internal combustion engine pass and a control system, the method comprising:
 determining, by the control system, that the internal combustion engine is in an operating phase in which the catalytic converter is not at its working temperature; and   activating, by the control system, an electrical load element that is powered by the internal combustion engine so that an additional load is placed on the internal combustion engine in response to said determining by the control system.   
     
     
         2 . The method of  claim 1 , wherein the engine system comprises a generator driven by the internal combustion engine, the electrical load being powered by the internal combustion engine via the generator. 
     
     
         3 . The method of  claim 1 , wherein the engine system includes a battery, and wherein the electrical load draws a current in excess of that available from the battery. 
     
     
         4 . The method of  claim 1 , wherein the electrical load is a catalytic converter heater. 
     
     
         5 . The method of  claim 4 , wherein the catalytic converter heater is integral to the catalytic converter. 
     
     
         6 . The method of  claim 4 , wherein the catalytic converter heater is external to the catalytic converter. 
     
     
         7 . The method of  claim 1 , wherein the additional load is applied until the catalytic converter reaches a predetermined temperature. 
     
     
         8 . The method of  claim 1 , wherein the additional load is applied until the catalytic converter reaches a predetermined temperature or until a predetermined time has elapsed, whichever occurs first. 
     
     
         9 . The method of  claim 1 , wherein the additional load is applied for a predetermined time. 
     
     
         10 . The method of  claim 1 , wherein the operating phase of the internal combustion engine is a start up phase. 
     
     
         11 . An engine system comprising:
 an internal combustion engine that is operable to apply drive to a drive train;   a catalytic converter through which exhaust gases from the internal combustion engine pass; and   a control system operable to determine that the internal combustion engine is in an operating phase in which the catalytic converter is not at its working temperature, and then to activate an electrical load element that is powered by the internal combustion engineso that an additional load is placed on the internal combustion engine in response to the determination by the control system.   
     
     
         12 . The engine system of  claim 11 , comprising a generator driven by the internal combustion engine, the electrical load being powered by the internal combustion engine via the generator. 
     
     
         13 . The engine system of  claim 11 , wherein the engine system includes a battery, and wherein the electrical load draws a current in excess of that available from the battery. 
     
     
         14 . The engine system of  claim 11 , wherein the electrical load element is in the form of a catalytic converter heater. 
     
     
         15 . The engine system of  claim 14 , wherein the catalytic converter heater is integral to the catalytic converter. 
     
     
         16 . The engine system of  claim 14 , wherein the catalytic converter heater is external to the catalytic converter. 
     
     
         17 . The engine system of  claim 11 , wherein the control system is operable to apply the additional load until the catalytic converter reaches a predetermined temperature. 
     
     
         18 . The engine system of  claim 11 , wherein the control system is operable to apply the additional load until the catalytic converter reaches a predetermined temperature or until a predetermined time has elapsed, whichever occurs first. 
     
     
         19 . The engine system of  claim 11 , wherein the control system is operable to apply the additional load for a predetermined time. 
     
     
         20 . The engine system of  claim 11 , wherein the operating phase of the internal combustion engine is a start up phase. 
     
     
         21 . A motor vehicle comprising an engine system, the engine system comprising:
 an internal combustion engine that is operable to apply drive to a drive train;   a catalytic converter through which exhaust gases from the internal combustion engine pass; and   a control system operable to determine that the internal combustion engine is in an operating phase in which the catalytic converter is not at its working temperature, and then to activate an electrical load element that is powered by the internal combustion engine so that an additional load is placed on the internal combustion engine in response to the determination by the control system.   
     
     
         22 . The motor vehicle of  claim 21 , comprising the electrical load element is in the form of a catalytic converter heater. 
     
     
         23 . The motor vehicle of  claim 21 , wherein the operating phase of the internal combustion engine is a start up phase. 
     
     
         24 . The motor vehicle of  claim 21 , wherein:
 the motor vehicle is a hybrid vehicle that also includes at least one electric drive motor; and   the operating phase of the internal combustion engine is one of a start up phase and an electrical drive phase.   
     
     
         25 . A method of controlling an engine system having an internal combustion engine and a catalytic converter, the method comprising:
 determining that the catalytic converter is not within a predetermined operating range of temperature;   based on said determining, activating a heater of the catalytic converter so that an additional load is placed on the internal combustion engine;   drawing power away from the internal combustion engine to provide power to the activated heater while maintaining an engine speed of the internal combustion engine; and   heating the catalytic converter with heat provided from both the heater and the internal combustion engine at least while the additional load is placed on the internal combustion engine.