What is the significance of diesel viscosity and lubricity?
1 Answers
Viscosity is one of the important quality indicators of diesel fuel, which is related to diesel transportation, pump operation, and spray conditions: 1. It affects the fuel supply volume. If the diesel viscosity is too low, it involves power loss in the injection pump, lubrication of fuel components, and internal leakage loss during operation in the fuel supply system, which instead reduces the effective fuel supply volume; conversely, if the viscosity is too high, it involves the engine design, size, and characteristics of the fuel injection system, causing the effective fuel supply volume to exceed the standard. Although this increases power, it leads to incomplete combustion, black smoke in the exhaust, and increased fuel consumption. 2. Diesel with too low viscosity spreads easily, has good fineness, but its penetration is small. During combustion, some air far from the fuel injector cannot mix with the diesel, thereby reducing the air utilization coefficient; diesel with high viscosity has the opposite effect. Therefore, diesel viscosity should be appropriate to facilitate the formation of a uniform combustible mixture. 3. It affects the lubrication of precision components in the fuel supply system. Moving components with precise fits, such as plunger components, needle valves, and needle valve bodies, mainly rely on diesel for lubrication. If the diesel viscosity is too low, the relative motion resistance of these components increases, leading to accelerated wear.
