The main cause is the decline in hydraulic efficiency due to mechanical wear. For every 0.1mm increase in the gap between the impeller and the pump casing (0.03-0.05mm for new parts), the volumetric efficiency decreases by 23%. To maintain the same flow rate, the motor speed needs to be increased by 15%. Bosch laboratory disassembly data shows that after 120,000 kilometers of driving, the median wear on the impeller end face reaches 0.18mm. At this point, the actual power consumption of the motor under 350bar conditions increases to 220W (185W for the new pump), with an increase of 18.9%. In 2019, Honda recalled 136,000 Civic vehicles due to this defect. The power overload of the faulty pump increased the early failure rate of the battery by 47%.
The deterioration of electrical contact leads to additional resistance loss. When the contact resistance between the copper brush and the commutator rises from ≤0.15Ω at the factory to 0.8Ω (a common value on the Volkswagen MQB platform), an additional 18.4W of heat energy is generated according to Ohm’s law (under a current of 6A). Delphi’s 2023 fault statistics indicate that the occurrence rate of this phenomenon increases by 300% in high-humidity coastal environments (humidity >80%). The brush contact voltage drop of Fuel Pump in use for three years reached 1.2V (0.3V for new parts), equivalent to a total power loss of 14%.
Lubrication failure deteriorates mechanical friction. When the oil film thickness of oil-impregnated bearings is less than 5μm (the design standard is 15μm), the coefficient of friction surges from 0.003 to 0.025. Ford’s durability test shows that at this point, the motor torque loss reaches 28%, and to maintain the rated speed, the input current needs to be increased by 19%. What’s more serious is the pitting on the raceway – the Toyota disassembly report shows that when the proportion of pitting is greater than 7%, the local friction temperature exceeds 160℃, forcing the protection circuit to increase the working current by 22% to compensate for the efficiency loss.
Pressure loss requires power compensation. When the filter is clogged and the pressure difference rises to 5bar (1.5bar for a new filter element), maintaining the same flow rate requires a 40% increase in motor power. Chevrolet Silverado measured data: When the system flow resistance increases by 50kPa·s/L, to maintain a flow rate of 2.5L/min, the controller automatically raises the duty cycle from 70% to 85%, corresponding to a 62W increase in power consumption (+25%).
The intelligent temperature control strategy increases power consumption. The new type of Fuel Pump integrates a PTC heating film (with a nominal power of 28W). It consumes 9.3Ah of power after continuous operation for 20 minutes in an environment of -20℃, accounting for 15% of the capacity of a common battery. Volvo conducted a test in northern Sweden and found that the total power consumption for a single preheating trip of the vehicle in the cold region reached 310Wh, which is 22% more than that of the normal temperature model. Although this function enhances the reliability of cold start, it increases the system’s average annual energy consumption by 17%.
The solution needs to be improved in multiple dimensions. Porsche adopted silicon nitride ceramic bearings on the 911 (992), which kept the frictional power consumption stable within ±3% deviation after 120,000 kilometers. The new type of motor with neodymium iron boron permanent magnet rotor (such as Bosch HDP6) reduces power consumption by 60% under the same working conditions and improves the overall efficiency of Fuel Pump in terms of comprehensive energy efficiency. The cost for users to replace the fuel filter regularly (every 30,000 kilometers) is only 25, which can avoid an average annual excess power consumption of 83 and battery wear and tear.