3600 and C280 Diesel Engine Fluids Recommendations Caterpillar

Recommendations for Heavy Fuel Oil

Cat 3600 Series engines can burn a wide range of heavy fuel oils. The 3600 Series engines that are configured for using heavy fuel oil have a special fuel system. The engines also have special components for the combustion chamber. These features help to resist the corrosive elements that are found in heavy fuel oil. Because of those special features, DO NOT use heavy fuel oil in 3600 Series engines that are configured to use distillate fuel. DO NOT use heavy fuel oil in C280 Series diesel engines.

Do not use these types of fuel in engines that are Tier 4 EPA certified.

3600 Series engines that are properly configured can operate on fuel which is within the specifications that are listed in Tables 1 and 2. Table 1 lists recommended specifications for heavy fuel oil that will help to provide maximum service life and performance. Table 2 lists the maximum bunkered fuel limits. If the fuel exceeds the limits that are listed in the Tables, Cat recommends diluting the heavy fuel oil with a distillate diesel fuel.

Note: All fuel grades listed in Tables 1 and 2 require appropriate fuel treatment prior to delivery to the injector. For information on fuel treatment see "CIMAC Background Design and Operation of Heavy Fuel Treatment Plants for Diesel Engines".

Note: For more information on operating a 3600 Series engine with heavy fuel oil, see Special Instruction, REHS0104, "Guidelines for 3600 Heavy Fuel Oil (HFO) Engines".

Vanadium and Sodium

Compounds of vanadium and sodium are corrosive at high temperatures. The limits that are listed in Tables 1 and 2 are ONLY for engines that have the proper components and equipment for treatment of the fuel.

If a fuel analysis reveals that the fuel has more than 200 ppm of vanadium and/or 30 ppm of sodium, the customer is encouraged to consult the Cat Engine factory. Analysis can ensure that the engine has the proper configuration and equipment for the fuel.

In addition to the limits on vanadium and sodium in ppm, limits are established for the comparative concentrations of these elements. Compounds of vanadium and sodium are especially corrosive when the concentration of sodium is more than 20 percent of the concentration of vanadium. Table 3 shows examples for calculating the percentage of sodium to vanadium.

The concentration of vanadium and sodium can also be expressed as a ratio. A ratio of vanadium to sodium that is five or more is acceptable. Table 4 shows examples for calculating the ratio of vanadium to sodium.

Note: Vanadium levels over 300 ppm will require a request for a special rating. A ratio of vanadium to sodium that is less than five will also require a request for a special rating.

Treatment of Heavy Fuel Oil (HFO)

Note: When HFO will be used, also refer to Special Instruction, REHS0104, "Guidelines for 3600 Heavy Fuel Oil (HFO) Engines".

Operation of a 3600 Series Engine with heavy fuel oil requires attention to maintenance intervals and inspections. Trained personnel are required for the treatment of the fuel and maintenance of the equipment.

The use of heavy fuel oil can involve these procedures:

• Storing of the fuel

• Filtering of the fuel

• Heating of the fuel

• Centrifuging of the fuel

• Centrifuging of the lube oil

• Cooling of the fuel injector tips

Additionally, the engine is modified for the use of heavy fuel oil. Extra engine maintenance is required.

For information on the systems for treatment and storage of heavy fuel oil, see the Special Instruction, REHS0104, "Guidelines For 3600 Heavy Fuel Oil (HFO) Engines".

Centrifuging of the Fuel

Fuel from the settling tank must be centrifuged continuously for proper treatment. Continuous centrifuging of the fuel provides these benefits:

• The fuel is maintained at a constant level in the day tank.

• The foaming of fuel in the day tank is minimized.

• Air and vapor that is contained in the return fuel has a constant distance for separating from the fuel.

• The cleanest fuel from the top of the day tank flows to the fuel conditioning module and the engine.

• Warm fuel is continuously supplied to the day tank reducing the need to heat the fuel. The convection currents are eliminated that originate at the heater coils. The impurities are allowed to settle.

• Fuel that returns to the settling tank from the lower portion of the day tank will have the most impurities. This fuel can be centrifuged again in order to remove the impurities.

Centrifuging of the Lube Oil

Heavy fuel oil introduces more combustion products into the crankcase than distillate fuel. The combustion products contaminate the lube oil. A remote mounted centrifugal separator will help to clean the engine crankcase oil increasing the service life of the oil. Continuous separation is required.

The flow rate is determined primarily by the engine power output. If the centrifuge is simultaneously receiving oil and discharging sediment, the minimum flow rate is 0.3 L/bkW hr (.026 gal/bhp hr).

Cooling of the Fuel Injector Tips

During engine operation with heavy fuel oil, the fuel injector tips are cooled. This helps to prevent wear and the formation of deposits.

For fuels with a maximum viscosity of 40 cSt at 50 °C (122 °F), excess fuel is routed through the tips in order to cool the tips. For this “series circuit” cooling, the engine is equipped with the required hardware. Additional external plumbing is not necessary.

For fuels with a viscosity that is above 40 cSt at 50 °C (122 °F), an external module for cooling the fuel injector tips is required. The module consists of several parts that include these components:

• Piping

• Tank with a sight gauge

• Filter for the coolant

• Differential pressure gauge (filter)

• Valves

• Pump

• Pressure gauge

• One temperature gauge before the engine and one temperature gauge after the engine

• An alarm for low coolant pressure

• Heat exchanger

A thermostatic regulator may also be required. For the coolant that recirculates from the engine, select a control valve that will maintain the temperature of the coolant between 50 to 65 °C (122 to 149 °F). Normally, the coolant is SAE 10W to SAE 30 grade diesel engine oil.

Maintain the coolant to the fuel injectors under the following conditions:

• Temperature of 55 to 65 °C (131 to 149 °F)

• Pressure of 276 to 441 kPa (40 to 64 psi)

• Flow rate of 6 liters per minute for each fuel injector

Do not operate the module before starting the engine. Regardless of the type of fuel that is used, always operate the module when the engine is running. Fresh coolant is constantly supplied to the fuel injector tips. High temperatures at the fuel injectors cause degradation of the coolant.

Note: Check the coolant level, the temperature, and the pressure frequently.

Filtering of the Fuel

The quality of the fuel is an important consideration for maintenance of the fuel filters. A poor quality of fuel can reduce the service life of the fuel filter elements by 50 percent or more. To increase the service life of fuel filter elements, use a good quality of fuel. Monitor the readings of the fuel gauges and service the fuel filters at the recommended intervals.

The secondary fuel filters that are supplied by Cat are mounted remotely from the engine. The filters are installed in the fuel supply line directly before the engine.

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Overheating the fuel or the fuel filter can result in personal injury and/or damage to the engine. Use extreme care and caution for heating of the fuel filter.

Heating of the fuel filter will enable the viscosity to be reduced. The fuel temperature and warm-up time depend on the type of fuel and installation.

Heating of the Fuel

Precise temperature control of heavy fuel oil is critical for the most complete combustion, centrifugal cleaning, and settling of contaminants. If the temperature is not properly controlled, sludge and vapors can form. This material inhibits the treatment of the fuel. Also, combustion of the fuel is reduced. The result is a reduction of the service life of the fuel system components and the engine.

Note: The temperatures that are required for controlling sludge and vapor mainly depend on the fuel quality. An analysis of the fuel is necessary to determine the proper temperature for both treatment and viscosity.

The following parameters can be used as initial indications of improper temperature control:

• Variation of the exhaust port temperatures

• Viscosity of the fuel

• Knocking

• Fuel temperature

• Opacity of the exhaust smoke

Use the jacket water heaters before starting an engine with heavy fuel oil. Use of the jacket water heaters will reduce the viscosity of the fuel in the fuel injectors. Startability will be improved.

Table 5 lists the jacket water temperatures that are appropriate for different fuel viscosities.

Normally, deactivate the jacket water heaters after the engine has started.

Analysis of Heavy Fuel Oil

Caterpillar Inc. does not provide analyses of heavy fuel oil. Chemical labs throughout the world can evaluate fuel properties on a regular basis. Analyses of heavy fuel oil may also be obtained from these organizations: independent testing laboratories, oil companies and marine regulating agencies. For accurate results, the analysis of heavy fuel oil must be performed at a laboratory with personnel that is familiar with this type of fuel. The following are some of the laboratories that can provide fuel analyses.

Det Norske Veritas (DNV)

Lloyd's Register Laboratory