Assessing the High-Temperature Deposit Formation of Paraffinic and Naphthenic Oil Blends Using the Oil Chute Method

Abstract

Due to the demand for higher efficiency, gas engine designs are changing in that gas engine oils are exposed to higher thermal stress and face challenges regarding the prevention of deposits. In this work, the “oil chute” laboratory test was used to study the high-temperature deposit-formation tendency of various paraffinic and naphthenic base oil blends. The oil chute is a setup that circulates oil through two different temperature zones, the hot zone being a heated metal chute that triggers deposit formation. In addition, the thermo-oxidative stability of the oil blends was investigated using an artificial alteration method. The results showed that naphthenic base oils have the capability of substantially reducing high-temperature deposit formation. However, they tend to degrade faster under thermo-oxidative stress. Therefore, finding the right balance between paraffinic and naphthenic base oil components will allow the formulation of gas engine oils that provide the right properties to cope with the higher stress levels they are subjected to in modern gas engines.