Catalytic converter heating

Abstract

The rate at which a catalytic converter heats up to its normal operating temperature range, (e.g., during a start up phase) is increased by applying an external load to an internal combustion engine. Applying the external load causes the engine to generate more heat, which can be used to reduce the time that it takes to bring the catalytic converter up to its working temperature. As a result, a reduction in emissions can be achieved.

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 whether the internal combustion engine is in a phase in which the catalytic converter is below its working temperature; and causing an external load to be applied to the internal combustion engine when the internal combustion engine is in a phase in which the catalytic converter is below its working temperature. 
   
   
       2 . The method of  claim 1 , wherein the external load is applied to the drive train. 
   
   
       3 . The method of  claim 2 , wherein the drive train includes an automatic transmission having a torque converter and wherein to apply said external load, the control system is operable to engage a drive mode with the torque converter immobilized. 
   
   
       4 . The method of  claim 3 , wherein to immobilize the torque converter, the control system is operable to apply a parking brake. 
   
   
       5 . The method of  claim 4 , wherein the parking brake is controlled electrically. 
   
   
       6 . The method of  claim 1 , wherein the control system causes an external load to be applied to an engine output shaft. 
   
   
       7 . The method of  claim 6 , wherein the engine output shaft is a crankshaft of the engine and wherein the control system causes a braking force to be applied to the crankshaft. 
   
   
       8 . The method of  claim 7 , wherein the braking force is applied by an electrically controlled crankshaft brake. 
   
   
       9 . The method of  claim 7 , wherein the braking force is applied by a visco-mechanical coupling. 
   
   
       10 . The method of  claim 1 , wherein the external load is applied for a predetermined period. 
   
   
       11 . The method of  claim 1 , wherein the external load is applied until the catalytic converter reaches a predetermined temperature. 
   
   
       12 . 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, wherein the control system is operable to determine when the internal combustion engine is in a phase in which the catalytic converter is below its working temperature; and to cause an external load to be applied to the internal combustion engine.   
   
   
       13 . The engine system of  claim 12 , wherein the control system is operable to cause the external load to be applied to the drive train. 
   
   
       14 . The engine system of  claim 13 , wherein the drive train includes an automatic transmission having a torque converter, and wherein the control system, in order to apply external load, is operable to engage a drive mode of the transmission and to immobilise the torque converter. 
   
   
       15 . The engine system of  claim 14 , wherein the control system, in order to immobilise the torque converter, is operable to apply a parking brake. 
   
   
       16 . The engine system of  claim 15 , wherein the parking brake is controlled electrically. 
   
   
       17 . The engine system of  claim 12 , wherein the control system is operable to cause an external load to be applied to an engine output shaft. 
   
   
       18 . The engine system of  claim 17 , wherein the engine output shaft is a crankshaft of the engine, and wherein the control system, is operable to cause a braking force to be applied to the crankshaft. 
   
   
       19 . The engine system of  claim 18 , comprising an electrically controlled crankshaft brake for applying the braking force. 
   
   
       20 . The engine system of  claim 18 , comprising a visco-mechanical coupling for applying the braking force. 
   
   
       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, the control system being operable to determine when the internal combustion engine is in a phase in which the catalytic converter is below its working temperature; and to cause an external load to be applied to the internal combustion engine.