Engine emissions control system

Abstract

An engine emissions control system may include an electronic control module and a nitrogen oxide sensor in communication with the electronic control module. The nitrogen oxide sensor may be mounted on an exhaust system of an engine and may be configured to provide the electronic control module with feedback indicative of an actual level of nitrogen oxide in an exhaust stream flowing through the exhaust system. The engine emissions control system may also include an engine parameter adjustment assembly controlled by the electronic control module. The electronic control module may automatically actuate the engine parameter adjustment assembly to adjust an engine flow until the actual level of nitrogen oxide reaches a desired level of nitrogen oxide.

1 . An engine emissions control system, comprising:
 an electronic control module;   a nitrogen oxide sensor in communication with the electronic control module, wherein the nitrogen oxide sensor is mounted on an exhaust system of an engine, and is configured to provide the electronic control module with feedback indicative of an actual level of nitrogen oxide in an exhaust stream flowing through the exhaust system; and   an engine parameter adjustment assembly controlled by the electronic control module, wherein the electronic control module automatically actuates the engine parameter adjustment assembly to adjust an engine flow until the actual level of nitrogen oxide reaches a desired level of nitrogen oxide.   
   
   
       2 . The control system of  claim 1 , wherein the engine parameter adjustment assembly includes a wastegate valve, and the engine flow is an intake air flow. 
   
   
       3 . The control system of  claim 1 , wherein the engine parameter adjustment assembly includes an exhaust induction valve, and the engine flow is an exhaust flow. 
   
   
       4 . The control system of  claim 1 , wherein the engine parameter adjustment assembly includes a fuel metering valve, and the engine flow is a fuel flow. 
   
   
       5 . The control system of  claim 1 , wherein the engine is a gaseous fuel internal combustion engine. 
   
   
       6 . The control system of  claim 1 , wherein the nitrogen oxide sensor is continuously exposed to the exhaust stream. 
   
   
       7 . The control system of  claim 1 , wherein the nitrogen oxide sensor is periodically exposed to the exhaust stream. 
   
   
       8 . The control system of  claim 7 , wherein the nitrogen oxide sensor is mounted on a bypass line, and the nitrogen oxide sensor is exposed to the exhaust stream by moving a bypass valve of the bypass line to an open position. 
   
   
       9 . A method of controlling engine emissions, comprising:
 monitoring nitrogen oxide levels in an exhaust stream of an engine using a nitrogen oxide sensor;   transmitting a signal indicative of an actual nitrogen oxide level from the nitrogen oxide sensor to an electronic control module;   comparing the actual nitrogen oxide level to a desired nitrogen oxide level; and   automatically adjusting an engine flow until the actual nitrogen oxide level reaches the desired nitrogen oxide level.   
   
   
       10 . The method of  claim 9 , wherein automatically adjusting the engine flow includes operating a wastegate valve to adjust intake air flow into the engine. 
   
   
       11 . The method of  claim 9 , wherein automatically adjusting the engine flow includes operating an exhaust induction valve to adjust exhaust flow into the engine. 
   
   
       12 . The method of  claim 9 , wherein automatically adjusting the engine flow includes operating a fuel metering valve to adjust fuel flow into the engine. 
   
   
       13 . An engine assembly, comprising:
 an engine; and   an engine emissions control system configured to automatically regulate the nitrogen oxide level in an exhaust stream of the engine, wherein the control system includes:   an electronic control module;   a nitrogen oxide sensor in communication with the electronic control module, wherein the nitrogen oxide sensor is mounted on an exhaust system of an engine, and is configured to provide the electronic control module with feedback indicative of an actual level of nitrogen oxide in an exhaust stream flowing through the exhaust system; and   an engine parameter adjustment assembly controlled by the electronic control module, wherein the electronic control module automatically actuates the engine parameter adjustment assembly to adjust an engine flow until the actual level of nitrogen oxide reaches a desired level of nitrogen oxide.   
   
   
       14 . The engine assembly of  claim 13 , wherein the engine parameter adjustment assembly includes a wastegate valve, and the engine flow is an intake air flow. 
   
   
       15 . The engine assembly of  claim 13 , wherein the engine parameter adjustment assembly includes an exhaust induction valve, and the engine flow is an exhaust flow. 
   
   
       16 . The engine assembly of  claim 13 , wherein the engine parameter adjustment assembly includes a fuel metering valve, and the engine flow is a fuel flow. 
   
   
       17 . The engine assembly of  claim 13 , wherein the engine is a gaseous fuel internal combustion engine. 
   
   
       18 . The engine assembly of  claim 13 , where the nitrogen oxide sensor is continuously exposed to the exhaust stream. 
   
   
       19 . The engine assembly of  claim 13 , wherein the nitrogen oxide sensor is periodically exposed to the exhaust stream. 
   
   
       20 . The engine assembly of  claim 19 , wherein the nitrogen oxide sensor is mounted on a bypass line, and the nitrogen oxide sensor is exposed to the exhaust stream by moving a bypass valve of the bypass line to an open position.