C175-16 Marine Engines Caterpillar

Programming Governor Gain Parameters

The governor gain parameters are set at the factory. The factory default settings are recommended for most applications. The default settings should allow the engine to respond quickly to transient load changes. The default settings should allow the engine to remain stable during all operating conditions. If the factory default setting does not provide satisfactory performance, the governor gain parameters can be adjusted.

The parameters in Table 1 can be adjusted.

Note: No engineering units are associated with the numbers in table 1.

Note: The range of the programmable setting is wide for flexibility. Do not expect to use the whole range. If the programmable setting is greater than the valid range, the system will revert to the factory default value.

Do not perform this procedure until you read this information and you understand this information.

Gain Explanations

Governor Gain Factor

The Governor Gain Factor is multiplied by the engine speed error. This value is derived by calculating the difference between the desired speed and the actual speed.

• If the Governor Gain Factor value is too large, the engine speed can overshoot the desired speed.

• If the Governor Gain Factor value is too small, the engine will accelerate slowly.

Governor Minimum/Maximum Stability Factor

The "Governor Minimum Stability Factor" functions in order to eliminate steady state speed error. The Governor Minimum Stability Factor is used by the Electronic Control Module (ECM) when the steady state speed error is less than 20 rpm.

The Governor Maximum Stability Factor functions in order to eliminate steady state speed error. The Governor Maximum Stability Factor is used when the steady state speed error is increasing and the engine speed error is greater than 20 rpm.

• If the Governor Minimum Stability Factor or the Governor Maximum Stability Factor is set too high, the ECM will provide additional fuel. The additional fuel will cause the engine speed to overshoot. The additional fuel will also cause the engine speed to oscillate.

• If the Governor Minimum Stability Factor or the Governor Maximum Stability Factor is too low, the engine will not achieve a steady state operation quickly.

Tuning Procedure

1. Turn the Engine Control Switch (ECS) to the STOP position. Connect the Caterpillar Electronic Technician (ET). Enable the engine overspeed protection prior to the adjustment procedure. Adjusting governor gain parameters without engine overspeed protection can result in serious engine damage. Ensure that engine overspeed protection is ON. Use Cat ET to program the parameter for engine overspeed.
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   Personal injury or death can result from engine overspeed. If the engine overspeeds, it can cause injury or parts damage. The engine should be equipped with a separate shutdown device, to protect against engine overspeed. Do not use for emergency shutdown.

2. Start the engine. Observe the control panel to ensure that the engine has reached the rated speed. The control panel will serve as the reference point for engine speed during this procedure.

3. Go to the configuration parameters screen in Cat ET.

   Note: A factory password is required for adjustment of the governor gain parameters. Once the password is entered, the values for the governor gain parameters can be adjusted. If a parameter value that is not a governor gain parameter is altered, a new password will be required. If the configuration parameters screen is stopped during the adjustment of a governor gain parameter, a new factory password will be required.

   Note: Any value may be returned to the factory default setting by entering a value of "0" into the configuration parameters screen.

4. Set up a field performance test. For example, the engine has poor response during specific load changes.

5. Perform the desired load change from step 4. Observe the response of the engine by viewing the engine speed on the control panel. Observe the engine response by looking at the frequency meter or by listening to the response of the engine.

6. Determine the setting to adjust. Refer to "Gain Explanations" and "Governor Minimum/Maximum Stability Factor".

   Note: Usually, the Governor Gain Factor should be higher than the Governor Minimum Stability Factor for optimum performance. The Governor Maximum Stability Factor is typically a larger value than the Governor Minimum Stability Factor.

7. Repeat steps 5, 6, and 7 until a desired engine response can be met. Use large adjustments (ten percent of original gain) initially for a coarse adjustment to engine response. Use smaller adjustments (one percent of total gain) as the engine response is closer to the desired response.