Diesel fuel pumps are engineered with components and design features to accommodate diesel fuel, which requires more external all-through lubricant surrogacy due to its inherently high-oil nature and legged nature. Diesel, which has a viscosity of approximately 2.0-4.5 centistokes at 40°C, necessitates a pump that can transport denser fluid without hindering flow rate or pressure. Diesel pumps generally run in the 10-15 PSI range for their standard systems, as compared to the typical 40-70 PSI for gasoline engines. This lower pressure also ensures the fuel is thin enough to flow yet not over aliquoting too quickly to the engine for combustion.
The high lubricity of diesel is an important property for the longevity of pump elements, and as a result diesel fuel pumps are constructed from wear resistant materials, to compensate for the additional lubrication carried by diesel. Diesel does, however, lubricate the internal pump components as it passes through, decreasing friction and decreasing wear on critical components including seals, bearings, and impellers relative to gasoline. Because of this natural lubricating effect, diesel pumps tend to last much longer than gasoline pumps, often giving some in excess of 150,000 miles of service before needing replacement.
To atomize diesel fuel properly, modern diesel engines using high-pressure fuel injection systems require pumps which produce pressure of more than 25,000 PSI. Common rail diesel injection systems are one of the most common technologies for controlling fuel pressure for combustion, and use a high-pressure fuel pump to provide pressurized fuel at a largely constant pressure to the engine enabling more optimal combustion and reduced emissions. Take heavy-duty trucks, for example — the high-pressure fuel pumps provide a great deal of fuel efficiency and power, both of which are key in industries such as logistics, where fuel costs play a huge role in profitability.
Another aspect that adds complexity to diesel fuel pump design is the need to handle diesel’s high energy density, which yields about 15% more power from a gallon than gasoline. While this higher density is an enabler for heavy-duty applications, it means that pumps need to operate at the high-pressure for long periods of time. Since cold temperatures can stiffen diesel fuel and put more stress on the pump, this has made cold startability one of many factors that suppliers of diesel fuel pumps consider when creating fuel.
Diesel applications require toughness in pump construction, as automotive expert Jeremy Clarkson put it, “Diesel engines need to be tough.” Diesel engines often endure rough treatment, and quality Fuel Pump options designed for these applications can withstand this stress while ensuring consistent fuel delivery, efficiency, and a long service life in diverse and demanding conditions.