The strong corrosiveness and hygroscopicity of E85 Fuel (containing 85% ethanol +15% gasoline) pose special requirements for Fuel Pump. Take the Bosch 044 series fuel pump as an example. It adopts a duplex stainless steel pump casing and fluororubber seals. Its resistance to ethanol corrosion is 12 times higher than that of ordinary nitrile rubber (SAE J2260 test data). After continuous operation for 5,000 hours in the E85 environment, the flow attenuation rate is only 3%, while that of ordinary fuel pumps can reach 23%. Research by the U.S. Department of Energy shows that the electrical conductivity of E85 fuel is 50 times higher than that of ordinary gasoline. This requires that the insulation grade of the internal circuit of the fuel pump needs to reach the IP67 standard to prevent the increase of short-circuit failure rate – the Delphi HFP-915 model adds a 0.2mm Teflon coating. Increase the insulation resistance value from 50MΩ to 500MΩ (ASTM D257 standard).
In terms of flow demand, since the energy density of E85 is 30% lower than that of gasoline, the engine needs to inject 34% more fuel to maintain the same power. Fuel pumps supporting E85 need to increase the flow rate from the conventional 200L/h to 270L/h. For example, the Walbro 450LPH model can maintain a flow rate accuracy of ±2% at a pressure of 3.5bar. Tests by the US EPA show that when an unmatched fuel pump uses E85, the probability of fuel filter clogging increases by 80%. Therefore, the AEM 380LPH model is equipped with a 50μm multi-layer filter screen, and the dust holding capacity is increased to 15g, which is three times that of ordinary pumps.
Material compatibility directly affects service life. The pH value fluctuation range of E85 (4.5-8.5) is wider than that of gasoline (6.0-7.5). The corrosion rate of the common aluminum pump body in E85 reaches 0.25mm per year, while the Denso 950-0115 model adopts ceramic coating technology, reducing the corrosion rate to 0.02mm per year. According to the ISO 16750-4 standard, the E85 fuel pump needs to maintain normal function within the temperature range of -40℃ to 130℃. The VDO FP48 series developed by Continental, by integrating heating elements, reduces the start-up time from 8 seconds of ordinary pumps to 3 seconds at a low temperature of -30℃.
The cost-benefit analysis shows that the procurement cost of the Fuel Pump adapted to E85 is 35%-50% higher than that of the conventional model, but the maintenance cycle is extended to 8 years / 150,000 kilometers (5 years / 100,000 kilometers for ordinary pumps). Take the Holley 12-306 model as an example. Its dual-speed control function reduces power consumption by 40% under low load and saves about 15 US dollars in electricity bills annually. The United States Department of Agriculture estimates that the fuel cost per mile of vehicles using E85 is 22% lower than that of gasoline. If they travel 15,000 miles a year, they can save $1,980 in three years, which is sufficient to cover the cost of fuel pump upgrades.
Among the mainstream products in the market, the nickel-phosphorus coated pump shaft of DeatschWerks DW400 enhances the wear resistance to HRC62 and supports ethanol concentrations up to E100. The ACDelco MU173 model equipped on the Chevrolet Silverado FlexFuel model in 2019, by increasing the impeller diameter (from 28mm to 35mm), maintains the fuel rail pressure stable at 4.5bar±0.2bar under the E85 operating condition, ensuring that the air-fuel ratio control accuracy reaches ±3%. The environmental benefits are equally significant. Data from the U.S. Department of Energy shows that each gallon of E85 reduces carbon emissions throughout its life cycle by 34%. If 20% of all vehicles in the United States were to switch to E85, the annual reduction would be equivalent to the carbon sequestration capacity of 110 million mature oak trees.