88625 2 Mercury GASKET (PORT)

Monitoring the Trends of Engine Performance
To maintain a program that is successful, several factors are important:
Record the data regularly when the engine is operating at similar loads and speeds.
Obtain accurate data.
At regular intervals, review the data in a graphic format.
Perform corrections before damage and/or downtime occurs.Accurate data is provided by accurate instruments and proper use of the instruments. The gauges and the sensing devices must be in good condition. This condition is especially true for thermocouples. Establish a program for calibrating the instruments periodically. Avoid using infrared thermometers for obtaining data. Be sure to read the gauges properly. Accurate recording of the data is also important.Use the following Steps to establish a program.
Establish a baseline for the engine parameters. The baseline is necessary in order to know the normal gauge readings. The new data will be compared to the baseline.
Use the data from the engine commissioning. The data is recorded for various loads. The data is recorded before any wear or deterioration takes place.
If there is no data from the engine commissioning, use data from the engine test cell. Understand that the data will not be specific to the site.
If data is not available from the engine commissioning or the engine test cell, calculate an average of the existing data.
Establish a new baseline after an overhaul.
Frequently record the new data during engine operation. For an example of a log to use, see this Operation and Maintenance Manual, "Hourly Performance Log" (Reference Information Section). Readings of some parameters depend on the engine load. Record the data when the engine is operating at a high load. This recording increases the accuracy of the data. Also, any reduction in performance will be revealed sooner. A load of 75 to 100 percent is recommended.
For operations with a consistent load cycle, record the data at the same time for each day.
If the load can be controlled, set the load to the same amount for each reading.Some parameters that are NOT affected by the load ARE affected by the engine rpm. Obtain the readings for these parameters when the engine is operating at the same rpm.Some parameters are not affected by either the load or the rpm. See Table 1.
Table 1
Parameters of Engine Operation
Parameters That Depend On the Load
Aftercooler and oil cooler water temperature (outlet)
Exhaust manifold pressure
Exhaust manifold temperature
Exhaust port temperature
Generator stator temperature
Inlet air restriction
Inlet manifold air pressure (boost pressure)
Inlet manifold air temperature
Jacket water coolant temperature (outlet)
Parameters That Depend On the RPM
Fuel filter differential pressure
Jacket water pressure
Lube oil pressure
Oil filter differential pressure
Parameters That Are Independent of the Load and RPM
Aftercooler and oil cooler water temperature (inlet)
Jacket water coolant temperature (inlet)
Lube oil temperature Note: A gauge reading that is abnormal may indicate a problem with operation or a problem with the gauge.
Illustration 1 g00543927
Example of a graph of engine oil pressure
(Y) Pressure in kPa
(X) Calendar days
(1) Baseline
(2) Operating pressure
(3) Setpoint (alarm)
Average the data for each day. Use a computer or graph paper in order to produce a graph of the data. Compare the new data to the baseline. This comparison will help to reveal the trends of the engine performance. Illustration 1 shows that the engine oil pressure was near baseline (1). Later, the operating pressure was approaching setpoint (3). The trend of operating pressure (2) indicated that the condition required investigation before activation of the alarm.
Compare the new data to the data from previous months. This comparison will be useful for scheduling reconditioning for the engine. Monitoring the Trends of Fuel Consumption
Fuel consumption depends on the following factors:
Engine load
The fuel efficiency of the engine
The service hours of the engineUse these two methods in order to obtain accurate data on fuel consumption:
Calculate the Specific Fuel Consumption. For this calculation, the weight of the fuel that was burned is divided by the electrical energy that was produced.
Calculate the Heat Rate. This calculation compensates for the fuel energy content of different fuels. For this calculation, the low heat value (LHV) of the fuel is divided by the electrical energy that was produced.Calculating the Specific Fuel Consumption
Use the equation that is in Table 2 to calculate the Specific Fuel Consumption.
Table 2
Equation For Calculating the Specific Fuel Consumption
F × D = SFC
ekW-hr
F is the liters of fuel that have been burned.
D is the density of the fuel. The density is expressed in grams per liter.
ekW-hr is the electrical kilowatt hours that were produced with the fuel.
SFC is the specific fuel consumption.
Table 3 is an example for using the equation that is in Table 2. The data in the example assumes the following conditions:
During this operation, the engine used 18440 L (4872 US gal) of fuel.
The density of the fuel was 987 gm per liter.
The operation generated 88 800 ekW.
Table 3
Example of the Equation for Calculating the Specific Fuel Consumption