Injector cleaning system based on pressure decay

Abstract

An injector cleaning system for use with an exhaust treatment device is disclosed. The injector cleaning system may have a supply of injection fluid and an injector configured to receive and inject the injection fluid. The injector cleaning system may also have a pressure sensor associated with the injector to generate a signal indicative of the pressure of the injection fluid supplied to the injector. The injector cleaning system may further have a controller in communication with the injector and the pressure sensor. The controller may be configured to determine a pressure decay rate of injection fluid supplied to the injector during a normal injection event based on the signal. The controller may be further configured to compare the determined pressure decay rate to an expected pressure decay rate, and supply cleaning fluid to the injector based on the comparison.

1 . An injector cleaning system, comprising:
 a supply of injection fluid;   an injector configured to receive and inject the injection fluid;   a pressure sensor associated with the injector to generate a signal indicative of the pressure of the injection fluid supplied to the injector; and   a controller in communication with the injector and the pressure sensor, the controller being configured to:
 determine a pressure decay rate of injection fluid supplied to the injector during a normal injection event based on the signal; 
 compare the determined pressure decay rate to an expected pressure decay rate; and 
 supply cleaning fluid to the injector based on the comparison. 
   
   
   
       2 . The injector cleaning system of  claim 1 , wherein supplying cleaning fluid initiates a cleaning event and the controller is further configured to determine a second pressure decay rate following every cleaning event to determine an effectiveness of the cleaning event. 
   
   
       3 . The injector cleaning system of  claim 2 , wherein a supplemental injection event is initiated for determination of the second pressure decay rate. 
   
   
       4 . The injector cleaning system of  claim 3 , wherein injection fluid associated with the supplemental injection event passes from the injector through an associated combustion chamber without combustion. 
   
   
       5 . The injector cleaning system of  claim 2 , wherein the controller is further configured to initiate a secondary cleaning event when the second pressure decay rate exceeds the expected pressure decay rate by a predetermined amount. 
   
   
       6 . The injector cleaning system of  claim 5 , wherein the controller is further configured to determine a third pressure decay rate following the secondary cleaning event and log a fault condition when the third pressure decay rate exceeds the expected decay rate by a predetermined amount. 
   
   
       7 . The injector cleaning system of  claim 1 , wherein the controller is configured to determine the pressure decay rate during every normal injection event. 
   
   
       8 . The injector cleaning system of  claim 1 , wherein the controller includes at least one map stored in memory thereof relating the comparison to an injector restriction amount, and the amount of cleaning fluid supplied to the injector is based on the injector restriction amount. 
   
   
       9 . The injector cleaning system of  claim 8 , wherein the at least one map includes a plurality of maps, each of the plurality of maps being indexed accordingly to an engine operational parameter. 
   
   
       10 . The injector cleaning system of  claim 1 , wherein supplying includes directing the cleaning fluid to mix with the injecting fluid upstream of the injector. 
   
   
       11 . The injector control system of  claim 1 , wherein the injector is located to inject the injection fluid into an exhaust stream to raise a temperature of the exhaust stream. 
   
   
       12 . A method of cleaning, comprising:
 pressurizing an injection fluid;   injecting the pressurized injection fluid during a normal injection event;   sensing a pressure decay rate associated with the normal injection event;   comparing the sensed pressure decay rate to an expected pressure decay rate; and   injecting a cleaning fluid based on the comparison.   
   
   
       13 . The method of  claim 12 , wherein injecting the cleaning fluid initiates a cleaning event and the method further includes determining a second pressure decay rate following every cleaning event to determine an effectiveness of the cleaning event. 
   
   
       14 . The method of  claim 13 , further including initiating a supplemental injection event is initiated for determination of the second pressure decay rate. 
   
   
       15 . The method of  claim 13 , further including initiating a secondary cleaning event when the second pressure decay rate exceeds the expected pressure decay rate by a predetermined amount. 
   
   
       16 . The method of  claim 15 , further including determining a third pressure decay rate following the secondary cleaning event and logging a fault condition when the third pressure decay rate exceeds the expected decay rate by a predetermined amount. 
   
   
       17 . The method of  claim 12 , wherein sensing the pressure decay rate includes sensing the pressure decay rate during every normal injection event. 
   
   
       18 . The method of  claim 12 , further including relating the comparison to a restriction amount, wherein an amount of cleaning fluid injected is based on the restriction amount. 
   
   
       19 . The method of  claim 12 , wherein injecting the cleaning fluid includes directing the cleaning fluid to mix with the injecting fluid prior to injection. 
   
   
       20 . An exhaust treatment system, comprising:
 a supply of injection fluid;   a sensor associated with the supply of injection fluid to generate a signal indicative of an injection fluid pressure;   a housing configured to receive a flow of exhaust;   an injector disposed within the housing to receive the supply of injection fluid and inject the injection fluid into the flow of exhaust;   a supply of cleaning fluid; and   a controller in communication with the sensor and the injector, the controller being configured to:
 determine a pressure decay rate of injection fluid supplied to the injector during a normal injection event based on the signal; 
 compare the determined pressure decay rate to an expected pressure decay rate; and 
 supply cleaning fluid to the injector in an amount based on the comparison.