Effective compounds on lubricity of diesel gas oil

The sulfur content of diesel gas oil will be regulated to a maximum of 0.05 mass% from July 1997. However, deeply desulfurized diesel gas oil has poor lubricity for distributor type injection pumps of diesel engines that use the gas oil for lubrication of their moving parts. In order to investigate the reason for poor lubricity of low sulfur diesel gas oil, the polar compounds in diesel gas oil were extracted and their effects were studied. Among the Polar compounds, phenols and carboxylic acids had good effects on lubricity of diesel gas oil, but since these acidic compounds were reduced with desulfurization, the low sulfur diesel gas oil had poor lubricity. On further investigation, it was observed that catechols and naphthenic acids also had good effects on lubricity of diesel gas oil.