Strategy for using exhaust stroke post-injection to elevate exhaust temperature for diesel particulate filter regeneration

Abstract

An engine control system ( 28 ) causes combustion chambers ( 20 ) to be fueled during an engine cycle by a main injection ( 38 ) ending no later than substantially at the TDC between compression and expansion strokes of the cycle without any further injection of fuel during the expansion stroke, and then during the exhaust stroke of the cycle, by a post-injection ( 40 ) for elevating the temperature of the gases into a regeneration temperature range for regenerating a diesel particulate filter ( 36 ).

1 . A diesel engine comprising:
 a fueling system for injecting diesel fuel into combustion chambers where the fuel combusts to power the engine;   an exhaust system through which gases created by combustion pass to atmosphere and which comprises an after-treatment device that treats the gases before leaving the exhaust system but at times requires regeneration by elevation of temperature of the gases to a regeneration temperature range;   an engine control system for processing various data to control various aspects of engine operation including fueling performed by the fueling system and regeneration of the after-treatment device;   wherein in consequence of a regeneration request, the control system causes the fueling system to fuel the combustion chambers during an engine cycle for a combustion chamber by a main injection ending no later than substantially at the TDC between compression and expansion strokes of the cycle without any further injection of fuel during the expansion stroke, and then during the exhaust stroke of the cycle, by a post-injection for elevating the temperature of the gases into the regeneration temperature range.   
     
     
         2 . A diesel engine as set forth in  claim 1  wherein the post-injection is caused to occur nearer TDC than BDC. 
     
     
         3 . A diesel engine as set forth in  claim 1  wherein the main injection causes the engine to operate by conventional diesel combustion. 
     
     
         4 . A diesel engine as set forth in  claim 1  wherein the after-treatment device comprises a diesel particulate filter. 
     
     
         5 . A diesel engine as set forth in  claim 4  wherein the post-injection is caused to occur nearer TDC than BDC. 
     
     
         6 . A motor vehicle comprising:
 a diesel engine for turning driven wheels through a drivetrain to propel the vehicle:   a fueling system for injecting diesel fuel into combustion chambers of the engine where the fuel combusts to propel the vehicle;   an exhaust system through which gases created by combustion pass to atmosphere and which comprises an after-treatment device that treats the gases before leaving the exhaust system but at times requires regeneration by elevation of temperature of the gases to a regeneration temperature range;   an engine control system for processing various data to control various aspects of engine operation including fueling performed by the fueling system and regeneration of the after-treatment device;   wherein in consequence of a regeneration request, the control system causes the fueling system to fuel the combustion chambers during an engine cycle for a combustion chamber by a main injection ending no later than substantially at the TDC between compression and expansion strokes of the cycle without any further injection of fuel during the expansion stroke, and then during the exhaust stroke of the cycle, by a post-injection for elevating the temperature of the gases into the regeneration temperature range.   
     
     
         7 . A motor vehicle as set forth in  claim 6  wherein the post-injection is caused to occur nearer TDC than BDC. 
     
     
         8 . A motor vehicle as set forth in  claim 6  wherein the main injection causes the engine causes the engine to operate by conventional diesel combustion. 
     
     
         9 . A motor vehicle as set forth in  claim 6  wherein the after-treatment device comprises a diesel particulate filter. 
     
     
         10 . A motor vehicle as set forth in  claim 9  wherein the post-injection is caused to occur nearer TDC than BDC. 
     
     
         11 . A method for initiating regeneration of an exhaust gas after-treatment device in an exhaust system of a diesel engine having a fueling system for injecting diesel fuel into combustion chambers where the fuel combusts to power the engine and an engine control system for processing various data to control various aspects of engine operation including fueling performed by the fueling system and regeneration of the after-treatment device, the method comprising:
 initiating regeneration by causing the fueling system to fuel the combustion chambers during an engine cycle for a combustion chamber by a main injection ending no later than substantially at the TDC between compression and expansion strokes of the cycle without any further injection of fuel during the expansion stroke, and then during the exhaust stroke of the cycle, by a post-injection.   
     
     
         12 . A method as set forth in  claim 11  comprising causing the post-injection to occur nearer TDC than BDC. 
     
     
         13 . A method as set forth in  claim 11  comprising injecting the main injection so as to cause the engine to operate by conventional diesel combustion.