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Title: Method and apparatus for controlling fuel/air mixture in a lean burn engine

Abstract

The system for controlling the fuel/air mixture supplied to a lean burn engine when operating on natural gas, gasoline, hydrogen, alcohol, propane, butane, diesel or any other fuel as desired. As specific humidity of air supplied to the lean burn engine increases, the oxygen concentration of exhaust gas discharged by the engine for a given equivalence ratio will decrease. Closed loop fuel control systems typically attempt to maintain a constant exhaust gas oxygen concentration. Therefore, the decrease in the exhaust gas oxygen concentration resulting from increased specific humidity will often be improperly attributed to an excessive supply of fuel and the control system will incorrectly reduce the amount of fuel supplied to the engine. Also, the minimum fuel/air equivalence ratio for a lean burn engine to avoid misfiring will increase as specific humidity increases. A relative humidity sensor to allow the control system to provide a more enriched fuel/air mixture at high specific humidity levels. The level of specific humidity may be used to compensate an output signal from a universal exhaust gas oxygen sensor for changing oxygen concentrations at a desired equivalence ratio due to variation in specific humidity specific humidity. As a result, the control system will maintainmore » the desired efficiency, low exhaust emissions and power level for the associated lean burn engine regardless of the specific humidity level of intake air supplied to the lean burn engine.« less

Inventors:
 [1];  [1];  [1]
  1. (San Antonio, TX)
Publication Date:
Research Org.:
National Renewable Energy Laboratory
OSTI Identifier:
871453
Patent Number(s):
US 5735245
Application Number:
08/735,105
Assignee:
Southwest Research Institute (San Antonio, TX) NREL
DOE Contract Number:  
ZCR-5-13519-01
Resource Type:
Patent
Country of Publication:
United States
Language:
English
Subject:
method; apparatus; controlling; fuel; air; mixture; lean; burn; engine; supplied; operating; natural; gas; gasoline; hydrogen; alcohol; propane; butane; diesel; desired; specific; humidity; increases; oxygen; concentration; exhaust; discharged; equivalence; ratio; decrease; closed; loop; control; systems; typically; attempt; maintain; constant; resulting; increased; improperly; attributed; excessive; supply; incorrectly; reduce; amount; minimum; avoid; misfiring; increase; relative; sensor; allow; provide; enriched; levels; level; compensate; output; signal; universal; changing; concentrations; due; variation; result; efficiency; emissions; power; associated; regardless; intake; burn engine; lean burn; oxygen concentrations; air supplied; oxygen sensor; control systems; relative humidity; oxygen concentration; equivalence ratio; closed loop; natural gas; power level; output signal; exhaust gas; air mixture; gas discharge; fuel control; intake air; gas discharged; humidity sensor; exhaust emissions; /123/

Citation Formats

Kubesh, John Thomas, Dodge, Lee Gene, and Podnar, Daniel James. Method and apparatus for controlling fuel/air mixture in a lean burn engine. United States: N. p., 1998. Web.
Kubesh, John Thomas, Dodge, Lee Gene, & Podnar, Daniel James. Method and apparatus for controlling fuel/air mixture in a lean burn engine. United States.
Kubesh, John Thomas, Dodge, Lee Gene, and Podnar, Daniel James. Tue . "Method and apparatus for controlling fuel/air mixture in a lean burn engine". United States. https://www.osti.gov/servlets/purl/871453.
@article{osti_871453,
title = {Method and apparatus for controlling fuel/air mixture in a lean burn engine},
author = {Kubesh, John Thomas and Dodge, Lee Gene and Podnar, Daniel James},
abstractNote = {The system for controlling the fuel/air mixture supplied to a lean burn engine when operating on natural gas, gasoline, hydrogen, alcohol, propane, butane, diesel or any other fuel as desired. As specific humidity of air supplied to the lean burn engine increases, the oxygen concentration of exhaust gas discharged by the engine for a given equivalence ratio will decrease. Closed loop fuel control systems typically attempt to maintain a constant exhaust gas oxygen concentration. Therefore, the decrease in the exhaust gas oxygen concentration resulting from increased specific humidity will often be improperly attributed to an excessive supply of fuel and the control system will incorrectly reduce the amount of fuel supplied to the engine. Also, the minimum fuel/air equivalence ratio for a lean burn engine to avoid misfiring will increase as specific humidity increases. A relative humidity sensor to allow the control system to provide a more enriched fuel/air mixture at high specific humidity levels. The level of specific humidity may be used to compensate an output signal from a universal exhaust gas oxygen sensor for changing oxygen concentrations at a desired equivalence ratio due to variation in specific humidity specific humidity. As a result, the control system will maintain the desired efficiency, low exhaust emissions and power level for the associated lean burn engine regardless of the specific humidity level of intake air supplied to the lean burn engine.},
doi = {},
journal = {},
number = ,
volume = ,
place = {United States},
year = {1998},
month = {4}
}

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