System and method for monitoring a filter

Abstract

An engine assembly may include an internal combustion engine configured to combust fuel. The combustion of fuel may produce exhaust and sound waves that may be directed into an exhaust line. A particulate filter may be operatively coupled to the exhaust line, and the particulate filter may be configured to filter the exhaust. The engine assembly may also include a sensor package operatively coupled to the exhaust line. At least a portion of the sensor package may extend into the exhaust line at a location downstream from the particulate filter. The sensor package may be configured to monitor the sound waves passing through the particulate filter and to produce an electrical signal indicative of the intensity of the sound waves.

1 . An engine assembly, comprising: 
 an internal combustion engine configured to combust fuel, wherein the combustion of fuel produces exhaust and sound waves that are directed into an exhaust line;    a particulate filter operatively coupled to the exhaust line, the particulate filter being configured to filter the exhaust; and    a sensor package operatively coupled to the exhaust line, wherein at least a portion of the sensor package extends into the exhaust line at a location downstream from the particulate filter, the sensor package being configured to monitor the sound waves passing through the particulate filter and to produce an electrical signal indicative of the intensity of the sound waves.    
   
   
       2 . The engine assembly of  claim 1 , wherein the exhaust line further includes an opening at a downstream end, and wherein the portion of the sensor package is configured to be inserted into the exhaust line through the opening.  
   
   
       3 . The engine assembly of  claim 1 , wherein the sensor package further includes: 
 a microphone configured to receive the sound waves and convert the sound waves into a signal;    a first filter configured to receive the signal and reduce frequencies of the signal that are below a first cutoff frequency, while allowing frequencies above the first cutoff frequency to pass, to produce a filtered signal; and    an envelope detector configured to receive the filtered signal and convert the filtered signal into the electrical signal.    
   
   
       4 . The engine assembly of  claim 3 , wherein the envelope detector further includes: 
 a rectifier configured to receive the filtered signal and convert the filtered signal into one of an entirely positive waveform and an entirely negative waveform, to produce a rectified signal; and    a second filter configured to receive the rectified signal and reduce frequencies of the rectified signal that are above a second cutoff frequency, while allowing frequencies below the second cutoff frequency to pass, to produce the electrical signal.    
   
   
       5 . The engine assembly of  claim 1 , wherein the electrical signal is received by a signal detector operatively coupled to the sensor package, and the signal detector is set with at least one of a high signal level, indicative of the particulate filter being clean, and a low signal level, indicative of the particulate filter being loaded.  
   
   
       6 . The engine assembly of  claim 5 , wherein the signal detector is configured to automatically trigger regeneration of the particulate filter when the electrical signal falls below the low signal level.  
   
   
       7 . The engine assembly of  claim 5 , wherein at least one of the high signal level and the low signal level is selectively adjusted based at least in part on the intensity of the sound waves produced by the internal combustion engine.  
   
   
       8 . A method of monitoring a particulate filter, comprising: 
 producing exhaust and sound waves by combusting fuel with an internal combustion engine;    directing the exhaust and sound waves through the particulate filter;    converting the sound waves into an electrical signal with a sensor package, the sensor package being operatively coupled to an exhaust line of the internal combustion engine at a location downstream from the particulate filter, and wherein at least a portion of the sensor package extends into the exhaust line; and    regenerating the particulate filter if the electrical signal falls outside a predetermined range.    
   
   
       9 . The method of  claim 8 , further including receiving the sound waves with a microphone of the sensor package, wherein the microphone produces a signal.  
   
   
       10 . The method of  claim 9 , further including reducing frequencies of the signal that are below a first cutoff frequency, while allowing frequencies above the first cutoff frequency to pass, to produce a filtered signal.  
   
   
       11 . The method of  claim 10 , further including converting the filtered signal into one of an entirely positive waveform and an entirely negative waveform, to produce a rectified signal.  
   
   
       12 . The method of  claim 11 , further including reducing frequencies of the rectified signal that are above a second cutoff frequency, while allowing frequencies below the second cutoff frequency to pass, to produce the electrical signal.  
   
   
       13 . The method of  claim 8 , further including selectively adjusting the predetermined range based at least in part on the intensity of the sound waves produced by the internal combustion engine.  
   
   
       14 . A machine comprising: 
 an internal combustion engine configured to combust fuel, wherein the combustion of fuel produces exhaust and sound waves that are directed into an exhaust line;    a particulate filter operatively coupled to the exhaust line, the particulate filter being configured to filter the exhaust; and    a sensor package operatively coupled to the exhaust line, wherein at least a portion of the sensor package extends into the exhaust line at a location downstream from the particulate filter, the sensor package being configured to convert the sound waves passing through the particulate filter into a voltage signal indicative of the intensity of the sound waves.    
   
   
       15 . The machine of  claim 14 , wherein the exhaust line further includes an opening at a downstream end, and wherein the portion of the sensor package is configured to be inserted into the exhaust line through the opening.  
   
   
       16 . The machine of  claim 14 , wherein the sensor package further includes: 
 a piezoelectric microphone configured to receive the sound waves and convert the sound waves into a signal;    a high-pass filter configured to receive the signal and reduce frequencies of the signal that are below a first cutoff frequency, while allowing frequencies above the first cutoff frequency to pass, to produce a filtered signal; and    an envelope detector configured to receive the filtered signal and convert the filtered signal into the voltage signal.    
   
   
       17 . The machine of  claim 16 , wherein the envelope detector further includes: 
 a full wave rectifier configured to receive the filtered signal and convert the filtered signal into one of an entirely positive waveform and an entirely negative waveform, to produce a rectified signal; and    a low-pass filter configured to receive the rectified signal and reduce frequencies of the rectified signal that are above a second cutoff frequency, while allowing frequencies below the second cutoff frequency to pass, to produce the voltage signal.    
   
   
       18 . The machine of  claim 14 , wherein the voltage signal is received by a voltage detector operatively coupled to the sensor package, and the voltage detector is set with at least one of a high voltage level, indicative of the particulate filter being clean, and a low voltage level, indicative of the particulate filter being loaded.  
   
   
       19 . The machine of  claim 18 , wherein the voltage detector is configured to automatically trigger regeneration of the particulate filter when the voltage signal falls below the low voltage level.  
   
   
       20 . The machine of  claim 18 , wherein at least one of the high voltage level and the low voltage level is selectively adjusted based at least in part on the intensity of the sound waves produced by the internal combustion engine.