When the pressure of the Fuel Pump exceeds 15% of the designed value, the stress of the fuel injector seal ring will surge from the nominal 12MPa to 20MPa, resulting in a 320% increase in the leakage probability (SAE J2044 test data). Take the Bosch EV14 fuel injector as an example. Its design pressure is 4.0bar. If the output pressure of the fuel pump reaches 5.5bar, the fuel injection volume deviation will expand from ±2% to ±8%, causing the fluctuation range of the air-fuel ratio to exceed ±1.2 (the limit value of the EPA Tier3 emission standard is ±0.5). In the 2023 NHRA straight-line acceleration race, a certain team failed to calibrate the fuel pressure regulator, causing the injector needle valve to hit the valve seat at a frequency of 120 times per second under a pressure of 5.8bar. After only 3 hours of operation, the wear depth reached 0.15mm (the safety threshold was 0.05mm).
Under the high PSI working condition of the fuel pump body, the force on the impeller bearing increases from the normal value of 180N to 350N, and the contact stress of the bearing balls exceeds 2.1GPa (the material fatigue limit is 1.8GPa). The measured data of the Volvo P3 platform shows that when the fuel pump pressure continuously exceeds 5.0bar, the lifespan of the ceramic bearings in its twin-turbo design drops sharply from the nominal 100,000 kilometers to 23,000 kilometers, and the noise sound pressure level rises from 68dB to 85dB. More seriously, high pressure causes the pressure difference of the fuel filter to increase from 0.3bar to 1.2bar, and the probability of filter paper breakage increases by 47% (ISO 4548-12 standard).
The circuit system is facing severe challenges. The current of the fuel pump motor has increased from the nominal 8A to 12A, causing the temperature of the wiring harness to soar from 60℃ to 105℃. If ordinary PVC insulation (with a temperature resistance of 105℃) is used, its insulation resistance will decrease from 1×10¹⁴Ω·cm to 1×10¹⁰Ω·cm, and the leakage current will increase from 0.01mA to 50mA. The 2024 Tesla OTA upgrade case shows that for the Model S Plaid model, due to software misjudgment, the peak pressure of the fuel pump reached 6.2bar, and the probability of triggering the high-pressure protection module to blow rose from 0.3% to 9.7%.
The emission control system is directly damaged. When the air-fuel ratio of the three-way catalytic converter fluctuates by more than ±1.0, the sintering temperature of the precious metal coating will drop from 650℃ to 580℃, resulting in a 300% increase in the failure rate of the catalyst. Tests by the California Air Resources Board (CARB) show that exceeding the fuel pump pressure by 15% will increase HC emissions from 0.02g/km to 0.15g/km (exceeding the limit by 650%), and at the same time, the probability of triggering the OBD-II fault code P0087 will rise from 0.5% to 82%.
The economic loss is significant. For every 1bar that exceeds the fuel pump pressure, the average annual maintenance cost increases by 1,200 yuan (including fuel injector replacement, catalytic converter cleaning, etc.). However, installing an electronic pressure regulator (with a cost of 800- 2,500 yuan) can control the system pressure fluctuation within ±0.15bar, restoring the fuel pump’s lifespan to 95% of the designed value. These data prove that precisely controlling the PSI of the fuel pump is a key defense line for maintaining the efficiency and compliance of the power system.