Setup for Certain G3306TA Air/Fuel Ratio Control Engines with a Wide Band O2 Sensor {108H, 1408, 1920} Caterpillar

Engine

G3306B (S/N: R6S1-UP)

Introduction

Do not perform any procedure in this Special Instruction until you have read the information and you understand the information.

This system is for engines that are equipped with Cat^® Air/Fuel Ratio (AFR) control system The AFR setup instructions that follow are intended to maintain emissions for fuel with a Lower Heating Value (LHV) of 800 BTU/ft3 to 2395 BTU/ft3. The engine control strategy is not designed to run on any fuels outside of this range. Maintenance of emissions is not guaranteed on engines that are run on fuels outside of this range. Caterpillar also recommends adjusting the AFR when the gas pressure regulator is serviced or inspected. This system is for engines that are equipped with Cat AFR control system.

The AFR setup instructions that follow are intended to maintain emissions for fuel with an LHV of 800 BTU/ft3 to 2395 BTU/ft3. The engine control strategy is not designed to run on any fuels outside of this range.

Maintenance of emissions is not guaranteed on engines that are run on fuels outside of this range. Caterpillar also recommends adjusting the AFR when the gas pressure regulator is serviced or inspected.

Reference Section

Reference: Testing and Adjusting, KENR6870, "G3304B and G3306B Engines" for additional information.

Required Parts

Installation Procedure

Software

1. Connect to the engine with 2016A or later version of Caterpillar^® Electronic Technician (Cat ET).

2. Download and save the Electronic Control Module (ECM) replacement file.

3. Generate and save the Product Status Report.

4. Connect with Win Flash.

5. Flash the engine ECM and Messenger with appropriate software.

Natural Gas/Field Gas Fuel Supply Pressure

1. Set the regulator inlet pressure between 83 kPag (12 psig) and 172 kPag (25 psig).

2. Set the regulator outlet pressure. Refer to Testing and Adjusting, KENR6870, "Gas Pressure - Check and Adjust".

Ignition Timing

The timing parameters allow the customer to program the ignition timing of the engine to meet the needs for specific applications and installations

Note: Timing will be provided within the Gas Engine Rating Pro (GERP) program

First Desired Timing

The "First Desired Timing" is determined with the methane number of the primary fuel that is being used. Obtain the timing information for the specific fuel and site conditions from the local Cat dealer. The timing can also be obtained using the Caterpillar Gas Engine Rating Pro (GERP) software program.

Note: If the fuel composition at a given site changes greater than five methane points, the timing will need to be reset.

Contact the local Cat dealer or use GERP if such a change occurs. A free copy of GERP can be obtained by going to the following link and searching GERP in the search field.

Note: More information regarding the GERP program can also be obtained from the website.

GERP can provide the maximum rating capability for conditions at a given site. Use the following procedure to use GERP.

1. Select "Gas Compression" under the "Application" drop-down box.

2. Select "G3306B" under the "Engine Model" drop-down box.

3. Select desired Aspiration.

4. Select desired Power Rating.

5. Select desired Emissions Rating.

Setting the Ignition Timing

1. Use the following procedure to set the timing value found in the "Determining Ignition Timing" section using the engine display panel.

   1. Select "Main Menu".

   2. Select "Configure".

   3. Select "Engine Configuration Parameters".

   4. Select "Timing Control".

   5. Select "Desired Engine Timing".

2. Select and change the "Desired Engine Timing".

Air/Fuel Ratio Setup for Natural Gas/Field Gas

Adjusting the Carburetor

Refer to Testing and Adjusting, KENR6870, "G3304B and G3306B Engines" , Carburetor (High-Pressure Gas) - Adjust.

Setting the Air/Fuel Ratio (AFR) Control

Before setting up the AFR control check for the following conditions below.

1. Verify installation of the engine exhaust catalyst.

   1. Install the catalyst as close as practical to the turbine outlet flange to ensure proper catalyst inlet temperature.

      Note: If the catalyst is not close enough to use the 510-4350 Sensor Harness As (MS Connector), the 508-2175 Control Harness As (J1939) will need to be used.

   2. The exhaust piping between the turbine outlet flange and catalyst should be insulated whenever possible.

   3. Optimal catalyst performance is achieved when inlet temperature is above 400° C (752° F).
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   Illustration 1	g06094423
   (1) Outlet temperature sensor (2) 394-9021 Oxygen Sensor (Wide Band) (3) Inlet temperature sensor (4) CAN resistor (5) Oxygen sensor connection

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   Illustration 2	g06095721
   (3) Inlet temperature sensor (6) 394-9020 Oxygen Sensor (Wide Band) (7) Inlet temperature sensor connection

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   Illustration 3	g06094577
   (2) 394-9021 Oxygen Sensor (Wide Band) (4) CAN resistor (8) 274-3782 Seal Cap (9) 484-0935 Sensor Harness As (10) Catalyst connection (11) Electronic control module (12) Main harness

2. Verify installation of the catalyst inlet/outlet thermocouples and O2 sensors.

   Note: The 394-9021 Oxygen Sensor (Wide Band) should be installed in the catalyst outlet. The 394-9020 Oxygen Sensor (Wide Band) should be installed in the catalyst inlet.

   1. Install the thermocouples within 30.5 cm (12 inch) from the catalyst and at least 6.4 cm (2.5 inch) into the exhaust stream. The thermocouples should be installed at the bottom half of the exhaust pipe on either side of the catalyst in a horizontal mounted catalyst.
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      Illustration 4	g06197032

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      Illustration 5	g06197044

   2. Secure O2 sensor wiring using the required parts listed in Table 2.

      Install the O2 sensors within 30.5 cm (12 inch) from the catalyst. The O2 sensors should be installed at the top half of the exhaust pipe on either side of the catalyst in a horizontal application. In a vertical mounted catalyst, install the O2 sensors perpendicular to the pipe. Refer to Illustration 4 and 5.

      Note: If installing on a non-close coupled catalyst configuration, the catalyst inlet Wide Band O2 sensor will need to be installed within 30.5 cm (12 inch) from the catalyst and at least 6.4 cm (2.5 inch) into the exhaust stream of the catalyst inlet.

      Note: Do NOT insulate the O2 sensors.

   3. Proper Strain Relief

      1. The harness should be secured every 6 inches or less over the entire length of the harness.

      2. Any harness bend radius should not exceed 20 mm.

      3. The harness that exits the O₂ sensor probe should not exceed a 15 degree angle to allow for proper strain relief at the sensing probe assembly.

      4. Overall bend distance at the probe should be a minimum of 60 mm.

3. Since stoichiometric varies with fuel property, the AFR control needs set up to deliver the optimum AFR for the fuel quality at the site. Setting up the AFR control involves adjustment of the input "Desired Emissions Gain Adjustment Percentage" as needed to meet emissions with the fuel quality on site. This input can be adjusted using Cat ET. Follow the procedure described in the next section to set this input. The parameter needs set upon first commissioning and thereafter verified & adjusted upon changes in fuel quality. Check the parameter every 750 hours for the initial 3000 service hours and every 1500 hours afterwards to ensure that emissions are met over time.

Desired Emissions Gain Adjustment Percentage Adjustment

1. With the ECM powered up and the engine not running, check for diagnostic codes or events. If no diagnostic codes or events are present, proceed with adjustment of "Desired Emissions Gain Adjustment Percentage" parameter.

2. Start the engine.

3. Monitor the coolant and oil temperatures and when appropriate, apply load as needed to reach maximum operating load. Ensure that the load is maintained as steady as possible. Verify that the catalyst temperatures have stabilized.

4. Connect service tool to the ECM, check if the AFR control is operating in closed loop by following the procedure below.
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   Illustration 6	g06094626

   1. At the menu bar, go to the "Diagnostics" menu and select "Diagnostic Tests".
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      Illustration 7	g06094629

   2. Double-click "System Troubleshooting Settings".

   3. Double-click "Emissions Feedback Mode". The current value should read "Oxygen Feedback".

      Note: Once the service tool is disconnected, the AFR control will default to closed loop control once the appropriate conditions are met.

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      Illustration 8	g06094633

   4. Measure and record the emissions downstream of the catalyst. Record the initial value of the input "Desired Emissions Gain Adjustment Percentage", if the emissions data was recorded with the input set to 0 percent, record 0 percent.

      Note: Adjust the parameter, in the section below, to meet the emissions. At each adjustment setting, wait at least 10 minutes between each adjustment. The 10 minutes will allow enough time for the catalyst temperature and emissions to stabilize.

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      Illustration 9	g06094636

      1. Evaluate your emissions measurements, if CO is high increase the percentage value in Cat ET in maximum 10 percent increments, from the initial value, with a 10 minute interval between each increment to allow catalyst to stabilize. The increments need to be whole numbers. At each set point, measure and record catalyst out emissions once the emissions have stabilized. Increasing the percentage value in Cat ET will result in leaner air/fuel ratio through the engine. Air/Fuel ratio leaner than stoichiometric for the fuel, will result in increase of NOx.

      2. Evaluate your emissions measurements, if NOx is high decrease the percentage value in maximum 10 percent increments, from the initial value, with a 10 minute interval between each increment to allow catalyst to stabilize. At each set point, measure and record catalyst out emissions once the emissions have stabilized.

         Decreasing the percentage value will result in richer air/fuel ratio through the engine. Once the air/fuel ratio is richer than stoichiometric for the fuel, NOx emissions will decrease and stay at the lowest level that can be achieved. Take several of data points, with the richer set point to confirm the low emissions with NOx, interpolate within a narrow range to determine an optimum setting for "Desired Emissions Gain Adjustment Percentage" that meets emissions requirements.

         Note: For applications with significant load variation, repeat the "Desired Emissions Gain Adjustment Percentage" adjustment procedure described at the lowest operating point that the application will run. Select an optimized "Desired Emissions Gain Adjustment Percentage" that will satisfy emissions requirements at multiple operating conditions.

      3. Input the optimized set point in Cat ET. The input may need a minor readjustment to meet emissions across all operating conditions.

         Note: The input is retained across power cycles.

5. Exit Cat ET. The engine will continue to operate "Oxygen Feedback" mode (closed loop control) as part of normal operation.

   As part of normal operation, engine control will calibrate to the catalyst using the new value for the "Desired Emissions Gain Adjustment Percentage" once all the enablement criteria are met. The calibration will be attempted after at least 1 hour since this input was last updated in Cat ET. The calibration process could take up to 30 minutes to complete and will repeat every 24 hours.

   The catalyst calibration is performed to ensure that optimum AFR is maintained as the catalyst ages over time. During the catalyst calibration period, the emissions may be outside the allowable limits. This mode of operation has been declared to the appropriate regulatory authorities.