Engine System Setup for Certified CG137-12 Generator Set Engines {1270, 1278} Caterpillar

Engine (Captive)

CG137-12 (S/N: SC31-UP)

Generator Set

CG137-12 (S/N: SC21-UP)

Introduction

Do not perform any of the following procedures without reading and understanding the information first.

The Air/Fuel Ratio setup instructions that follow are intended to maintain emissions for fuel with a Lower Heating Value (LHV) of 820 to 1400 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 Air/Fuel Ratio when the gas pressure regulator is serviced or inspected.

Set the Natural Gas/Field Gas Fuel Supply Pressure

Regulator inlet pressure should be set between 275 to 414 kPa (40 psi to 60 psi). Regulator outlet pressure should be set so that the carburetor inlet pressure is 1.6 kPa (6.5 inch of H₂O).

Determining the 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 Caterpillar 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 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. More information regarding the GERP program can also be obtained from the website.

https://catoilandgas.cat.com

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

1. Select "Electric Power" under the "Application" drop-down box.

2. Select the desired engine by selecting "CG137-12" under the "Engine Model" drop-down box.

3. In the "Emissions Desc" drop-down box select "EPA Certified".

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 "All Set Points".

   4. Select "Engine Configuration Parameters".

   5. Select "Timing Control".

   6. Select "Desired Engine Timing".

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

Air/Fuel Ratio Setup for Natural Gas/Field Gas

Adjusting the Gas Pressure Regulator

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Illustration 1	g03820603
(1) Adjustment screw

1. Turn adjustment screw (1) counterclockwise until the screw stops. The carburetor is set to full rich.
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   Illustration 2	g03820605
   (2) Cap

2. Remove cap (2) from the gas pressure regulator.

3. Start the engine and run at low idle. Adjust the gas pressure regulator using the 8T-5160 Gas Regulator Setting Tool to obtain a pressure of 1.6 kPa (6.5 inch of H₂O) from the regulator to the carburetor.

   Note: Turning the disk clockwise will increase the differential pressure. Turning the disk counterclockwise will decrease the differential pressure.

Setting the Air/Fuel Ratio (AFR) Control

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

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

   1. The thermocouples need installed 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 of the exhaust pipe on either side of the catalyst.

   2. The O2 sensors need installed within 30.5 cm (12 inch) from the catalyst. The O2 sensors should be installed at the top of the exhaust pipe on either side of the catalyst.

2. Follow the Application and Installation Guidelines for insulation of the exhaust pipe to the catalyst. The catalyst and the O2 sensors should NOT be insulated.

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 either Cat^® Electronic Technician (ET) or by the Electronic Modular Control Panel (EMCP 4.4). 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. Verify the parameter when the fuel quality changes by 5MN.

Desired Emissions Gain Adjustment Percentage Adjustment

1. With the ECM powered up and the engine not running, check the Malfunction Indication Lamp (MIL) indicator. The MIL light should not be lit to 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, ensuring at least 400° C (752° F) at the catalyst inlet and outlet. Ensure that load is maintained as steady as possible. Verify that the catalyst temperatures have stabilized.

4. If the service tool is connected to the ECM, check if the AFR control is operating in closed loop by following the procedure below.
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   Illustration 3	g03823277

   1. At the menu bar, go to the "Diagnostics" menu and select "Diagnostic Tests".
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      Illustration 4	g03823324

   2. Double-click on "System Troubleshooting Settings".
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      Illustration 5	g03823326

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

   4. Click "Cancel" and exit the screen.

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

5. Measure and record 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%, record 0%.

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

   1. Increase the percentage value in Cat ET in 10% 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 , or EMCP 4.4, 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 and total hydrocarbon (THC) emissions as shown below. Take several data points, with the leaner set point to confirm the increase in NOx emissions.

   2. Decrease the percentage value in 10% 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, total hydrocarbon emissions will increase as shown below, NOx emissions will decrease and stay at the lowest level that can be achieved. Take several data points, with the richer set point to confirm the low emissions with NOx and higher emissions in total hydrocarbons. Based on the results from the preceding steps, interpolate within a narrow range to determine an optimum setting for "Desired Emissions Gain Adjustment Percentage" that meets emissions requirements.
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      Illustration 6	g03820790

   3. Repeat the "Desired Emissions Gain Adjustment Percentage" adjustment procedure described at 10% load (or the lowest operating point that the application will run). Select an optimized "Desired Emissions Gain Adjustment Percentage" that will satisfy emissions requirements at both 10% and maximum operating load.

   4. Input the optimized set point in Cat ET or EMCP 4.4. The input may need a minor readjustment to meet emissions across all operating conditions.

      Note: The input is retained across power cycles. However, this value will need to be reentered when software is reflashed on the engine.

6. 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 1 hour since this input was last updated in Cat ET. The calibration process could take up to 30 minutes to complete. 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.

Note: In general, most emissions analyzers report total hydrocarbon emissions (THC). However, emissions need reported for non-methane, non-ethane hydrocarbons (NMNEHC) portion of the total hydrocarbons (THC). More emissions measurements may be needed to subtract the methane & ethane emissions from total hydrocarbons emissions since the catalyst cannot oxidize/convert methane emissions across it.

Adjust the Turbocharger Waste Gate Setting

Use the procedure below to adjust the turbocharger waste gate setting if applicable.

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Illustration 7	g03743321
(1) Cap (2) Locknut (3) Adjustment screw

1. For engines with an adjustable exhaust bypass valve, adjust the valve to obtain a throttle angle of 60 degrees to 70 degrees at full load. The adjustment is made to obtain the correct angle of throttle at full load.

   1. Remove cap (1).

   2. Loosen locknut (2).

   3. Turning adjustment screw (3) will increase the boost. Increasing the boost will decrease the throttle angle.

      Note: The bypass valve may require adjustment several times.

2. If the engine RPM is unstable, verify that the gas line pressures at no load and full load are within the correct range. The pressure must not vary more than 1.7 kPa (0.25 psi) for low-pressure systems.

3. Operate the engine throughout the expected load range. Verify that the engine RPM is stable. Verify that the following parameters are within the correct range at full load.

   • Throttle angle

   • Exhaust oxygen

   • CO

   • NOx

4. Check the final adjustments to the engine to ensure the compliance with the emissions requirement. Monitor the emissions analyzer. Verify that the exhaust emissions after the catalyst are within the limits. Refer to the engine TMI "Emissions Data" sheet.

Malfunction Indication Lamp (MIL) Operation

Illustration 8	g03667543
(1) Malfunction Indication Lamp

Drive Cycle : After an engine startup, if the event system does not find any fault condition of any of the MIL-related diagnostics for one minute after the Emission Feedback Mode turns to "Oxygen Feedback" that will be considered as one drive cycle. Every drive cycle needs an engine start. An engine stop is sufficient for the next drive cycle.

For normal operation without a MIL diagnostic event in the previous drive cycle, the MIL will power on at every ECM power on. The MIL will stay on until the engine starts the cranking cycle.

The engine ECM will turn on the MIL when there is an engine diagnostic code activated. The MIL will turn off when the diagnostic code is cleared. The MIL will clear either when the issue is corrected or has been attended to by a technician and been reset.

The codes listed in Table 1 are emissions-related codes related to the MIL operation.

Clearing the MIL : The MIL can be cleared using the EMCP panel by hitting the "Reset" button after the engine has been serviced. No factory password is required to clear the code.

If the malfunction or system error does not recur for four drive cycles when the malfunctioning system is being evaluated, the MIL may shut off. For all other diagnostic codes, the MIL will turn off when the error does not repeat while the malfunctioning system is being evaluated.