The fuel system on a diesel engine is a highly specialized set of components which…
The fuel temperature supplied to the engine can affect unit injector life and maximum power capability. Reduced lubrication capability due to high temperature/low viscosity fuel may result in component scuffing. The minimum allowable viscosity at the injectors is 1.4 cSt. A maximum fuel temperature limit of 66°C (150°F) to the unit injectors,
regardless of fuel viscosity, prevents coking or gumming of the injectors. The maximum fuel viscosity to the unit injectors of 20 cSt prevents overpressure damage to the injectors.
Maximum fuel temperature limits to the low-pressure fuel transfer pump for Common Rail Fuel systems vary with engine model. Values are listed below in Table 4.
The engines are power set at the factory, and higher fuel temperatures will reduce maximum power capability. The fuel stop power reduction is 1% for each 6°C (10°F) fuel supply temperature increase above the maximum fuel temperature limit. If the engine is operating below the fuel stop limit, the governor will add fuel as required to maintain the required engine speed and power.