System for controlling exhaust emissions

Abstract

A method for controlling exhaust emissions is disclosed. The method includes producing exhaust having hydrocarbons and directing the exhaust through a converter. The method also includes directing the exhaust from the converter to an environment and determining a first rate indicative of a rate of hydrocarbons directed to the environment. The method further includes comparing the first rate with a predetermined rate and adjusting the production of exhaust, if the first rate is greater than the predetermined rate.

1 . A method for controlling exhaust emissions comprising: 
 producing exhaust, the exhaust including hydrocarbons;    directing the exhaust through a converter;    directing the exhaust from the converter to an environment;    determining a first rate indicative of a rate of hydrocarbons directed to the environment;    comparing the first rate with a predetermined rate; and    adjusting the production of exhaust, if the first rate is greater than the predetermined rate.    
   
   
       2 . The method of  claim 1 , wherein producing exhaust includes operating an engine and adjusting production of exhaust includes changing parameters of the engine operation.  
   
   
       3 . The method of  claim 1 , further including determining the first rate as a function of a first amount indicative of an amount of hydrocarbons absorbed by the converter  
   
   
       4 . The method of  claim 3 , further including: 
 determining a second rate indicative of a rate of hydrocarbons converted by the converter; and    determining the first amount as a function of the first rate and the second rate.    
   
   
       5 . The method of  claim 3 , further including: 
 estimating a temperature of the converter; and    determining the second rate as a function of the temperature and the first amount.    
   
   
       6 . The method of  claim 5 , wherein the temperature is an average temperature of the exhaust upstream and downstream of the converter.  
   
   
       7 . A system for monitoring emissions comprising: 
 an engine configured to produce hydrocarbons at a first rate;    a converter configured to convert hydrocarbons at a second rate and release hydrocarbons to an environment at a third rate; and    a controller configured to adjust parameters of the engine to produce hydrocarbons at a fourth rate less than the first rate when the third rate is greater than a predetermined rate.    
   
   
       8 . The system of  claim 7 , further including at least one sensor configured to establish at least one signal indicative of at least one operating parameter of the engine, wherein the controller is further configured to determine the first rate as a function of the at least one signal.  
   
   
       9 . The system of  claim 7 , further including at least one sensor configured to establish a first temperature indicative of a temperature of hydrocarbons within the converter.  
   
   
       10 . The system of  claim 7 , wherein the engine is configured to produce exhaust, the exhaust being directed through the converter, the produced hydrocarbons being a portion of the exhaust, the system further including: 
 a first sensor configured to sense a temperature of the exhaust upstream of the converter; and    a second sensor configured to sense a temperature of the exhaust downstream of the converter;    wherein the controller is configured to determine a first temperature as an average of the temperature of the exhaust upstream of the converter and the temperature of the exhaust downstream of the converter.    
   
   
       11 . The system of  claim 10 , wherein the controller is further configured to determine the third rate as a function of the first temperature and an amount of hydrocarbons absorbed by the converter.  
   
   
       12 . The system of  claim 11 , wherein the controller is further configured to determine the amount of hydrocarbons absorbed by the converter as a function of the first, second, and third rates.  
   
   
       13 . The system of  claim 9 , wherein: 
 the converter is configured to convert hydrocarbons into substances more innocuous to an environment than hydrocarbons; and    the controller is further configured to determine the second rate as a function of the first temperature.    
   
   
       14 . The system of  claim 13 , wherein the controller is further configured to: 
 determine a first amount of hydrocarbons indicative of an amount of hydrocarbons absorbed by the converter; and    determine the third rate as a function of the first temperature and the first amount.    
   
   
       15 . The system of  claim 7 , wherein the converter includes a catalyst configured to absorb hydrocarbons into the catalyst or transform hydrocarbons into innocuous substances.  
   
   
       16 . A method of operating an engine comprising: 
 monitoring at least one engine parameter indicative of an operational condition of an engine configured to produce exhaust including hydrocarbons;    monitoring a temperature and a pressure each indicative of an operational condition of a converter, the converter including a catalyst configured to convert the hydrocarbons at a first rate and release the hydrocarbons to an environment at a second rate; and    changing a status of the engine when the second rate is greater than a predetermined rate.    
   
   
       17 . The method of  claim 16 , wherein the converter is further configured to absorb the hydrocarbons at a fourth rate, the method further including: 
 determining a third rate indicative of a rate of production of the hydrocarbons as a function of the at least one engine parameter;    determining the first rate as a function of the temperature;    determining the second rate as a function of the temperature and an amount of the at least one hydrocarbon absorbed by the catalyst.    
   
   
       18 . The method of  claim 17 , wherein the third rate is substantially equal to the sum of the first rate, the second rate, and the fourth rate.  
   
   
       19 . The method of  claim 17 , further including: 
 determining a standardizing factor as a function of the temperature and the pressure; and    adjusting the second rate as a function of the standardizing factor.    
   
   
       20 . The method of  claim 19 , further including determining the amount of the hydrocarbons absorbed by the catalyst as a function of the first rate, the third rate, and the adjusted second rate.  
   
   
       21 . The method of  claim 20 , wherein the converter is configured to absorb the hydrocarbons by trapping the hydrocarbons within the converter.  
   
   
       22 . The method of  claim 16 , wherein changing a status of the engine includes varying at least one of a valve timing, ignition timing, or an air-fuel ratio.