Soot & Acid Control in Diesel Lubricating Systems 2004-01-3014
Soot and combustion by-products are acidic and create serious challenges for the buffers in engine lubricating oil additive packages. Diesel engines, utilized in a wide variety of operating modes, have shown that the Neutralization Number (NN) of the engine oil can decrease below the Total Base Number (TBN) threshold of 2.00 mg/g HCL (0.1N), which is one indicator commonly used to signal an oil change prompt. Current model engines may utilize retarded injection timing, and Exhaust Gas Re-circulation (EGR), to reduce oxides of nitrogen emissions. This configuration generates higher soot levels than an engine electronically managed for peak performance output. Soot is also abrasive, causing increased cylinder and ring wear, and can increase oil viscosity as the concentration increases. Therefore, to optimize the performance of the engine lube system, it is desirable to enhance the function of the oil additive package and remove soot as a contaminant, either of which can extend oil drain intervals and improve operational uptime.