Fuel pumps for handling high-ethanol blended fuels (such as E85) need to meet special material and design standards. Taking the Bosch 044 series as an example, after its duplex stainless steel Pump casing and fluororubber seals were immersed in E85 for 5,000 hours, the dimensional change rate was only 0.2% (tested by SAE J2260). The expansion rate of common nitrile rubber seals can reach 8%. Experiments by the U.S. Department of Energy show that when using E85, the Fuel Pump flow rate needs to increase by 34% to compensate for the low calorific value of ethanol (67% of gasoline). Therefore, the AEM 380LPH model can maintain a flow rate accuracy of 380L/h±3% at a pressure of 5.0bar by increasing the impeller diameter to 38mm. Meet the demand of 2000cc/min fuel injectors.
In terms of electrical safety, the electrical conductivity of ethanol Fuel is 50 times higher than that of gasoline (up to 200pS/m), and the insulation grade of the internal circuit of the Fuel Pump is required to be upgraded to IP69K. The Delphi HFP-915 adopts a 0.3mm Teflon coating, which increases the insulation impedance of the wiring harness from 50MΩ to 1000MΩ, preventing the risk of short circuits. In the 2023 NHRA straight-line acceleration race, the vehicle using this pump completed 200 consecutive quarter-mile sprints under E85 conditions, with a zero failure rate of the electronic control system (the failure rate of the ordinary pump was 4.2%).
Material compatibility tests show that the ceramic bearings of Walbro 450LPH Fuel Pump have a wear rate of only 0.002mm/ 10,000 kilometers in the E100 environment (0.015mm for ordinary steel bearings). The annual corrosion depth of its anodized aluminum pump body in ethanol fuel with a pH value of 4.5-9.0 is ≤0.01mm (ASTM G31 standard). Petrobras’ 2024 report indicates that the FlexFuel model using this pump has an average service life of 150,000 kilometers in the E100 environment, which is 300% longer than that of ordinary pumps.
Thermal management technology is of vital importance. The latent heat of vaporization of E85 is 36% higher than that of gasoline, making it prone to cavitation. The Holley Hydramat series reduces the inlet pressure fluctuation of the Fuel Pump from ±0.5bar to ±0.1bar through porous medium diversion technology, and reduces the cavitation probability by 82%. The measured data shows that at an oil tank temperature of 45℃, this pump can still maintain 95% of its rated flow rate, while the traditional pump attenuation drops to 78%. The EU’s “New Battery Act 2027” requires that the MTBF (Mean Time Between Failures) of Fuel pumps in the E85 environment be ≥ 8,000 hours. Currently, only 23% of commercially available products meet this standard.
The cost-benefit analysis indicates that the procurement cost of the Fuel Pump adapted to E85 is 40-60% higher than that of the ordinary model, but the annual maintenance cost is reduced by 55% (due to the reduced frequency of carbon deposit cleaning). The actual test conducted by the owners of Chevrolet Silverado shows that after using the DeatschWerks DW400 Fuel Pump, the cost per kilometer of E85 fuel is 22% lower than that of gasoline, and the fuel cost can be saved by 4,500 yuan in three years. The environmental benefits are equally significant. A study by the University of Michigan indicates that if 10% of vehicles across the United States were to switch to E85-compatible Fuel pumps, annual carbon emissions could be reduced by 18 million tons, equivalent to the carbon sequestration of 4 million acres of forest. These data prove that the selection of professional-grade Fuel pumps is the engineering basis for achieving efficient utilization of ethanol fuel.