E3 Rich-Burn Gas Engine Control System

    Natural Gas Engine Compliance

     E3 Rich Burn Banner

    Keeping your natural gas engine in compliance is a fact of life for anyone operating a natural gas fueled reciprocating engine. Emission compliance adds costs to the maintenance of rich burn natural gas engines. Woodward’s E³ Rich Burn air to fuel ratio (AFR) control system for natural gas engines minimizes the resources needed to meet emissions compliance.

    Reduce your cost of compliance by staying in compliance

    E³ Rich Burn integrates fuel control and catalyst control in a single system using StableSense™ Technology. Unlike first-generation A/F controls, E³ Rich Burn effectively analyzes, controls and optimizes engine and catalyst functions without continuous readjustment.

    The system can be used as a stand-alone air-fuel ratio controller or as a complete gas engine emissions and engine control. It is designed for stoichiometric, spark-ignited natural-gas engines used in gas compression, power generation, pumping, and other stationary applications ranging from under 300 kW (400 hp) to over 2 MW (2700 hp). It has full authority over spark, fuel, and air. Additionally, diagnostics such as misfire detection and other health monitoring and engine protection functions are integrated into the system.

    The E³ Rich Burn system-based solution analyzes and controls all of the functions of your engine and catalyst to optimize the amount of time your engine is in compliance. The system controls the air-fuel ratio through a fuel metering trim valve. By means of the exclusive StableSense™ oxygen feedback sensor in the exhaust and the unique StableSense™ control algorithm the air-fuel ratio (lambda) is controlled slightly below 1 to optimize the three-way catalyst emission reduction.

     E3 Rich Burn System

    Take a closer look at how the E3 Rich Burn Control System can reduce your cost of compliance.

    Request a copy of our white paper entitled "Proven Techniques for Keeping Natural Gas Engines in Emissions Compliance".


    System Overview

    • Provides complete misfire detection, speed control, engine protection, and sequencing ignition in addition to AFR control
    • Is simple to calibrate
    • Is easy to use on a day-to-day basis and will notify the operator if an out-of-compliance condition may exist
    • Optimizes the amount of time the engine is in compliance as compared to other products on the market
    • Utilizes proven automotive technology to solve the problems of the industrial marketplace

    StableSense(TM) sensors

    • New, more rugged, industrialized natural gas specific oxygen sensors
    • Sensors can be replaced without recalibration of the control

    New StableSense (TM) Control Software

    • Emission control adopted from mobile industrial natural gas engine applications
      • dithers the exhaust flow to the catalyst, which makes the compliance window appear to be “wider” while accounting for intake temperature swings
      • on-board diagnostics provide out-of-compliance alarming 
    • Misfire detection using Instantaneous Crank Angle Velocity (ICAV) detection and advanced model-based algorithm that monitors variations with a high signal-to-noise-ratio to ensure no false alarms  
    • Balances the load on dual bank engines

    Systems Approach

    • Can combine engine speed/load control
    • Keeps emissions in compliance (catalyst control)
    • Ignition trim
    • Reduces the number of “boxes” and inter-box communications issues
    • Uses Woodward valves designed for the application 



    By executing advanced control algorithms, using proper oxygen sensors, gathering pertinent engine operating information, and controlling the entire engine operation as a system, Woodward's E3 system has proven to be technologically superior to control approaches presently being used. The summaries below illustrate the impact that an E3 system can make in reducing costs and enhancing performance.


    The E3 Rich Burn system on a Caterpillar 3412 engine
    driving an irrigation pump in Southern California

     E3 rich burn system on California irrigation pump engine

    The operator had difficulty keeping their natural gas engine in compliance with local, state, and federal exhaust emission regulations. Keeping the engine in compliance required a technician to travel to the site weekly to take measurements and “tweak” the control to get it back into compliance. Then there were several hours of paperwork that needed to be completed and submitted to the appropriate regulatory agency to document what had been done.

    The engine operator estimated that the costs associated with the engine being out of compliance totaled about 90 hours per month. Assuming a labor rate of $50/hour, the total annual cost per engine in their fleet was $54,000. That cost was eliminated by converting to Woodward’s E3 Rich Burn system. Their monitoring interval was lengthened from weekly to monthly and required no re-adjustments, thereby eliminating the submittal of follow-up reporting. Currently, the engine has been operating continuously in complete compliance without any re-adjustment for over two years with 8000 hours of runtime while experiencing normal changes in environmental and operating conditions. 


    The E3 Rich Burn system on a Waukesha 7044 engine
    driving a gas compressor in Wyoming

     E3 Rich Burn system on compressor pump engine

    The operator employs six full-time technicians working 60 to 70 hours per week to keep their 400 natural gas engines functioning within an annual compliance testing cycle. At this pace, technicians could only react to current “emergencies.” With the state considering increasing the testing cycle from annually to quarterly, the labor costs will increase significantly.

    Woodward’s E3 Rich Burn system assured that the evaluation engine remained in compliance, eliminating the time and expense previously required to bring it back into compliance. Currently, the engine has been operating continuously in complete compliance without any re-adjustment for over 6000 hours while experiencing the typical changes in environmental and operating conditions.





    E3 emission control systems can be retrofitted to your existing engines by a Woodward Recognized Engine Retrofit (RER) partner. Find information on an RER in your area from the listing below.


    Recognized Retrofit Partners

    Alberta Governor Service: Western Canada provinces of British Columbia, Alberta, Saskatchewan, Manitoba 

    Provinces of New Brunswick, Newfoundland and Labrador, Nova Scotia, Ontario, Prince Edward Island, and Quebec, and territories of Northwest Territories, Nunavut, and Yukon: Select an RER closest to you.

    Drake Controls: California, Kansas, Oklahoma, New Mexico, southwestern Nevada, Texas, Mexico

    Governor Control Systems: Alabama, Alaska, Arkansas, Florida, Georgia, Hawaii, Idaho North, Kentucky, Louisiana, Mississippi, North Carolina, Oregon, South Carolina, Tennessee, Virginia, Washington State, and West Virginia

    Peaker Services: Midwest: Illinois, Indiana, Iowa, Michigan, Minnesota, Missouri, Nebraska, North Dakota, Ohio, South Dakota, Wisconsin; Northeast: Connecticut, Delaware, Maine, Maryland, Massachusetts, New Hampshire, New Jersey, New York, Pennsylvania, Rhode Island, Vermont.

    Winn-Marion: Rocky Mountains: Arizona, Colorado, Idaho, Montana, Nevada, New Mexico, Utah, Wyoming; western Nebraska, western North Dakota, western South Dakota

     Alaska, Oregon, Washington, Hawaii: Select an RER closest to you.


    Recognized Retrofit Partners

    Governor Control Services 








    Product Specification  

    Technical Manual 26473 
     Please contact a Woodward Recognized Engine Retrofit (RER) partner 


    E3 Rich Burn Product Overview

    Product Information
    Industry Article

    Rich burn natural gas engine solution

    Read study published in April 2012 CompressorTech Magazine

    Open pdf file »