A variety of fuel oils, also known as middle distillates, is marketed for use in diesel engines. Their properties and performance depend upon the refining practices employed and the nature of the crude oils from which they are produced. Because of constituents in the oil, some crude oils are naturally suited for refinement into high-grade fuels while others are best used for lower-grade fuels. Similarly, high-grade fuels, low-grade fuels and the various grades between them provide choices for the most suitable fuel for any given installation. Note: The use of very high-grade or very low-grade fuel oils often requires modification to the fuel system and special consideration of additional costs that may be encountered. Contact your Cat dealer for information regarding the use of these fuel types.
Low Grade
Low-grade fuels produce a higher heat value which translates into more engine power, but they also produce more contaminates that could negatively impact engine-life. Additionally, the use of low-grade fuel oil in diesel engines often produces darker exhaust and a more pronounced odor. These attributes may be objectionable in hospital, office, commercial or urban settings and require the use of a higher-grade fuel.
The high sulfur content often found in low-grade fuels causes corrosion, wear and deposits in the engine. Fuels that are not volatile enough or donโt ignite rapidly may leave harmful deposits in the engine and may cause poor starting or running under adverse operating conditions. The use of low-grade fuels may require the use of high priced, higher detergent lubricating oils and more frequent oil changes to yield appropriate performance and engine life.
High Grade
High-grade fuels burn cleaner, but have a lower heat value, which yields slightly less power. Aviation jet fuels and kerosene are considered high-grade fuels and seldom contribute to the formation of harmful engine deposits and corrosion. Other attributes of high-grade fuels include the benefits of faster engine starting and less frequent overhauls, and the drawback of reduced lubricity.
American Society for Testing and Materials (ASTM) Due to the different engine applications, designs and sizes, standards for the limits of fuel properties have been set by the American Society for Testing and Materials (ASTM). Utilizing the correct fuel for the engine will minimize wear of the injection system, allowing easier starting and improve component service life.
Experience has proven that distillate fuels meeting basic specifications will result in optimum
engine performance and durability. Depending on fuel costs and availability, the proper use of alternative fuels such as crude oil, blended oil or residual oil can also provide cost competitive engine operation.