There were clear compatibility risks with KEMSO’s early 2000-2010 scroll fuel pumps. Laboratory immersion tests show that the corrosion rate of its carbon brush holder coating (nickel-copper alloy) in E10 ethanol gasoline reaches 0.028mm/ year (only 0.004mm in ordinary gasoline), resulting in the contact resistance increasing to 320% of the initial value after three years of use. In 2015, due to the mandatory promotion of the E10 in the Thai market, the report showed that the failure rate of the KP-200 series pumps soared by 41%. The main failure modes were armature short circuit (accounting for 63%) and commutator oxidation (accounting for 29%).
The difference in sealing materials leads to particularly prominent leakage risks. The volume expansion rate of traditional nitrile rubber (NBR) seals in the E10 environment is as high as 22% (the upper limit of 15% in ASTM D471 standard), reducing the sealing pressure at the joint of the pump body to 0.3MPa (the design requirement is ≥0.8MPa). The modern solution is to use fluororubber material (FKM), whose anti-swelling coefficient has been increased to only 3.7%, but the cost per piece has increased by $7.5. Measured data show that the KEMSO pump without upgraded seals experienced fuel leakage (leakage rate >15 drops per minute) after operating for 1,500 hours in tropical climates.
The flow attenuation is due to the change in the properties of ethanol. The viscosity of E10 gasoline is 17% lower than that of pure gasoline, resulting in the volumetric efficiency of the vane pump dropping from 92% to 87%. KEMSO Technical Announcement KP-TB-2022 states that the KD series vane pumps need to consume an additional 8% of power to maintain the same pressure when conveying E10. If they operate at full load continuously, the temperature will exceed 105℃ (the upper limit of the standard is 95℃). At this point, it is recommended to switch to the KV series plunger pump, whose working pressure is stable at 450±5kPa (±25kPa for vane pumps).
The new models have been fully adapted since 2021. The Fuel Pump (such as KT-450i) with ceramic shaft sleeves and platinum-iridium alloy contacts has passed the 1500-hour continuous test in accordance with ISO 1817 standard, and the ethanol tolerance concentration range has been extended to E25. Its intelligent control module can automatically adjust the power according to the dielectric constant (ε value) of the oil: under the E10 working condition, the current is controlled at 7.2±0.3A (8.1A for ordinary gasoline), extending the brush life to 15,000 hours (+65% compared to the basic type).
Cost-effectiveness needs to be evaluated by scenario. For individual users, it costs 280 to switch to a compatible pump assembly, which is 133% higher than the initial investment for repairing an old pump (120 for replacing seals and bearings). However, the fleet operation data shows that the average annual failure rate of the oil pumps adapted for E10 is only 0.3 times per 10,000 units, while the failure rate of the old pumps that have not been modified is 2.7 times per 10,000 units (with an average downtime loss of 430 per failure), and the modification cost can be recovered within 18 months. An extreme case occurred during the 2022 Australian floods. A logistics company caused fuel contamination in 23 trucks due to the use of non-E10 compatible pumps, with a single cleaning cost exceeding 18,000.
The certification mark is the core basis for judgment. The pump bodies of KEMSO that comply with the E10 standard are all engraved with elliptical marks (containing ethanol molecular formula C₂H₅OH), and the interior adopts a polyamide-imide composite coating (thickness ≥50μm). Users need to check the material specifications in Section 7.3 of the product manual: If the material Code of the seal is not FFKM or metal matrix composite material (Code MMC-7), there is a risk of seal failure after a maximum of 30,000 kilometers.