Fuel supply component purging system

Abstract

A method of purging fuel supply components for a combustion chamber of a regeneration assembly is disclosed. A regeneration cycle is performed during which fuel is supplied from a fuel source to the combustion chamber with fuel supply components including a fuel supply circuit and at least one fuel injector unit. At least a first purging cycle is initiated to purge residual fuel from the fuel supply components. During the purging cycle, a flow of purging gas is directed to the at least one fuel injector unit to purge residual fuel from the at least one fuel injector unit. Also during the purging cycle, a flow of purging gas is directed to the fuel supply circuit to purge at least a portion of the fuel in the fuel supply circuit toward the fuel source.

1 . A method of purging fuel supply components for a combustion chamber of a regeneration assembly, comprising:
 performing a regeneration cycle during which fuel is supplied from a fuel source to the combustion chamber with fuel supply components including a fuel supply circuit and at least one fuel injector unit;   initiating at least a first purging cycle to purge residual fuel from the fuel supply components;   during the purging cycle, directing a flow of purging gas to the at least one fuel injector unit to purge residual fuel from the at least one fuel injector unit; and   during the purging cycle, directing a flow of purging gas to the fuel supply circuit to purge at least a portion of the fuel in the fuel supply circuit toward the fuel source.   
   
   
       2 . The method of  claim 1 , further including:
 during the purging cycle, implementing a purging strategy including a plurality of events, the purging strategy including directing flow of purging gas to the at least one fuel injector unit during at least one fuel injector unit purging event, and directing flow of purging gas to the at least one fuel injector unit and to the fuel supply circuit during at least one fuel injector unit and fuel supply circuit purging event.   
   
   
       3 . The method of  claim 2 , wherein implementing the purging strategy further includes:
 during the purging cycle, precluding flow of purging gas to the at least one fuel injector unit and the fuel supply circuit during at least one hiatus event.   
   
   
       4 . The method of  claim 3 , wherein implementing the purging strategy further includes:
 during the purging cycle, implementing a purging strategy including a plurality of fuel injector unit purging events, a plurality of fuel injector unit and fuel supply circuit purging events, and a plurality of hiatus events.   
   
   
       5 . The method of  claim 2 , wherein the plurality of events occur in a timed sequence with one event following immediately after another event, further including:
 during the purging cycle, directing flow of purging gas from an air pump under pressure in the at least one fuel injector unit purging event and in the at least one fuel injector unit and fuel supply circuit purging event.   
   
   
       6 . The method of  claim 1 , further including:
 directing the flow of purging gas under pressure from a gas source;   monitoring the pressure to determine whether the pressure is below a predetermined minimum pressure; and   initiating a pressure deficiency flag in a controller when the monitored pressure is below a predetermined minimum pressure during a purging cycle.   
   
   
       7 . The method of  claim 6 , further including:
 initiating at least a second purging cycle after a predetermined time interval subsequent to terminating the at least a first purging cycle; and   initiating the at least a second purging cycle after a time interval shorter than the predetermined time interval in response to initiating a pressure deficiency flag in the controller.   
   
   
       8 . The method of  claim 1 , further including:
 monitoring at least one parameter indicative of whether fuel injection component performance may benefit from an additional purging cycle; and   initiating an additional purging cycle in response to the monitored parameter indicating fuel injection component performance may benefit from the additional purging cycle.   
   
   
       9 . The method of  claim 8 , wherein the parameter is pressure, and further including:
 monitoring pressure in the fuel supply circuit; and   initiating the additional purging cycle responsive to an increase in pressure beyond a predetermine pressure indicative that fuel injection component performance may benefit from the additional purging cycle.   
   
   
       10 . The method of  claim 1 , further including:
 at the onset of a regeneration cycle, moving a valve to a position permitting fuel to be supplied from the fuel source to the combustion chamber; and   at the onset of the at least a first purging cycle, moving the valve to a position inhibiting fuel from being supplied from the fuel source to the combustion chamber and permitting fuel to flow from the fuel supply circuit toward the fuel source.   
   
   
       11 . The method of  claim 1 , further comprising:
 during the purging cycle, selectively opening and closing at least one on/off valve to effectuate a control strategy that substantially purges fuel from the fuel injector unit and from at least a portion of the fuel supply circuit.   
   
   
       12 . A system for supplying fuel to a regeneration assembly during a regeneration cycle, and for purging fuel supply components during a purging cycle, comprising:
 a fuel supply circuit configured to supply fuel from a fuel source to the regeneration assembly;   a gas flow path configured to supply a purging gas from a gas source to the fuel supply circuit;   a fuel enable valve configured to permit fuel to flow from the fuel source, through the fuel supply circuit, to the regeneration assembly when the fuel enable valve is in a first position, and configured to permit fuel to flow away from the regeneration assembly and toward the fuel source in a second position; and   a controller configured to control flow of purging gas from the gas source to the fuel supply circuit to purge at least a portion of the fuel within the fuel supply circuit toward the fuel source when the fuel enable valve is in the second position.   
   
   
       13 . The system of  claim 12 , further including:
 at least one on/off valve in the fuel supply circuit and selectively movable between an on position and an off position, the at least one on/off valve disposed between the fuel enable valve and the regeneration assembly; and   at least one fuel injector unit connected to the fuel supply circuit and configured to inject fuel into the regeneration assembly;   wherein the controller is further configured to control flow of purging gas from the gas source to the fuel supply circuit to purge fuel from the at least one fuel injector unit when the at least one on/off valve is in the off position, and configured to control flow of purging gas from the gas source to the fuel supply circuit to purge at least a portion of the fuel within the fuel supply circuit toward the fuel source when the fuel enable valve is in the second position and the at least one on/off valve is in the on position.   
   
   
       14 . The system of  claim 13 , wherein the at least one on/off valve includes a pilot on/off valve and a main on/off valve, and further including:
 a pilot fuel flow path in the fuel supply circuit configured to direct fuel to the at least one fuel injector unit; and   a main fuel flow path in the fuel supply circuit configured to direct fuel to the at least one fuel injector unit;   wherein the controller is further configured to control flow of purging gas from the gas source to the fuel supply circuit to purge at least a portion of the fuel from the pilot fuel flow path toward the fuel source when the fuel enable valve is in the second position and the pilot on/off valve is in the on position, and wherein the controller is configured to control flow of purging gas from the gas source to the fuel supply circuit to purge at least a portion of the fuel from the main fuel flow path toward the fuel source when the fuel enable valve is in the second position and the main on/off valve is in the on position.   
   
   
       15 . A machine, comprising:
 an engine system including an engine and an exhaust flow path;   a filter assembly in the exhaust flow path;   a regeneration assembly configured to regenerate the filter assembly and including a combustion chamber;   at least one fuel injector unit associated with the combustion chamber, and a fuel supply circuit configured to supply fuel from a fuel source to the at least one fuel injector unit;   a source of purge air, and a purge air flow path in communication with the fuel supply circuit and the at least one fuel injector unit; and   a controller configured to control the flow of purge air from the source to purge fuel from the at least one fuel injector unit, and configured to control the flow of purge air to purge fuel within the fuel supply circuit toward the fuel source.   
   
   
       16 . The machine of  claim 15 , wherein the controller is configured to purge fuel from the fuel supply circuit and from the at least one fuel injector unit after engine startup. 
   
   
       17 . The machine of  claim 15 , wherein the controller is configured to purge fuel from the fuel supply circuit and from the at least one fuel injector unit after the engine is stopped. 
   
   
       18 . The machine of  claim 15  wherein the machine is an on-highway truck, and the source of purge air is a brake system compressor. 
   
   
       19 . The machine of  claim 15 , further including:
 a fuel enable valve configured to permit fuel to flow from the fuel source, through the fuel supply circuit, to the regeneration assembly when the fuel enable valve is in a first position, and configured to permit fuel to flow away from the regeneration assembly and toward the fuel source in a second position.   
   
   
       20 . The machine of  claim 19 , further including:
 a pilot fuel flow path in the fuel supply circuit configured to direct fuel to the at least one fuel injector unit; and   a main fuel flow path in the fuel supply circuit configured to direct fuel to the at least one fuel injector unit;   wherein the controller is further configured to control flow of purging gas from the gas source to the fuel supply circuit to purge at least a portion of the fuel from the pilot fuel flow path toward the fuel source when the fuel enable valve is in the second position and the pilot on/off valve is in the on position, and wherein the controller is configured to control flow of purging gas from the gas source to the fuel supply circuit to purge at least a portion of the fuel from the main fuel flow path toward the fuel source when the fuel enable valve is in the second position and the main on/off valve is in the on position.