DOOR 4514697 - Caterpillar

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 exchangerA 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 injectorDo 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.
For heavy fuel oil with a viscosity of 40 cSt at 50 °C (122 °F), the viscosity of the fuel must be reduced prior to the fuel filters. This will allow fuel to pass through the filter elements without causing the elements to collapse. Reduce the viscosity to a range that is between 15 and 20 cSt at 50 °C (122 °F).
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.
The viscosity of the fuel at the engine must be between