Experimental model for prediction of tip temperature of diesel injector nozzle in dual-fuel engines

Abstract

Dual-fuel technology enables Diesel engines to use natural gas as fuel injected into the intake. Ignition is achieved through the injection of fuels with high cetane numbers. This technology offers a cleaner and more economical burning for commercial engines. However, this fuel change leads to an increase in the tip temperature of the injector nozzle, causing the formation of deposits and coking in this component. Here, experimental and numerical studies were carried out in an engine converted to operate in dual-fuel mode, with the aim of developing a model to predict the dome temperature of the diesel injector nozzle. The following relevant parameters were found: the rate of Diesel replacement by compressed natural gas, combustion center, air-fuel equivalence ratio, Diesel injection pressure, exhaust gases recirculation rate, plenum air temperature, and engine coolant temperature. The tip temperature results were analyzed and except for the Diesel injection pressure, every parameter was found to influence this temperature being optimized. The temperature obtained through a new model shows a good correlation with the values measured with a deviation of less than 2% when the amount of Diesel injected is varied, and less than 1% when the engine coolant temperature and combustion center are varied.