Fuel Additive

Fuel additives, commonly known as "fuel treatments" or "fuel boosters", refer to functional chemical compounds added to fuel to compensate for inherent fuel property shortcomings or impart new performance characteristics, with dosage typically measured in trace amounts (ranging from parts per million to low percentages). Fuel additives are primarily divided into petrol additives and diesel additives, with core functions spanning carbon deposit removal, fuel atomisation enhancement, octane rating improvement, lubrication, and component protection.

System Composition and Working Principle

Currently, the vast majority of fuel additives on the market are formulated fromfour major additive concentrates(BASF, Lubrizol, Chevron, and Afton) combined with specialised functional compounds. Based on their functional application, additives are classified into two main categories:

• Keep-Clean Type (Maintenance Type): Formulated with a lower concentration of active detergents, its primary role is to inhibit carbon deposit formation. Active components form a protective film over metal surfaces, encapsulating unstable fuel components that form under high temperatures into oil-soluble micelles and preventing their agglomeration and deposition via electrostatic repulsion, thereby keeping the fuel system clean.

• Clean-Up Type (Restorative Type): Formulated with a higher concentration of active detergents (with Polyetheramine/PEA content typically exceeding 30%), it exhibits stronger surface activity. It penetrates into the pores of existing carbon build-up, disrupting its structure and breaking it down into microscopic particles that are combusted along with fuel and discharged through the exhaust. This type is suited for engines already exhibiting symptoms of carbon fouling.

The primary active cleaning agents includePolyetheramine (PEA) ,Polyisobutylene amine (PIBA) , and Mannich bases. Among these, PEA delivers outstanding thermal stability, remaining active in high-temperature zones such as the combustion chamber to effectively remove carbon build-up on piston crowns and fuel injector nozzles in direct injection engines; PIBA focuses predominantly on cleaning intake valves.

In addition, there areoctane boosteradditives. Their active ingredients are typically metallic anti-knock agents such as methylcyclopentadienyl manganese tricarbonyl (MMT), which temporarily raise octane ratings and suppress engine knocking when high-octane fuel is unavailable. However, long-term use is discouraged, as it can accelerate combustion chamber carbon accumulation and foul oxygen sensors and catalytic converters.

Applicable Scenarios and Realistic Limitations

Fuel additives are not universally effective across all vehicles; their actual efficacy depends heavily on engine architecture, operating conditions, and vehicle mechanical health.

• Applicable Scenarios: Indirect injection (GDI) modelsdriven in stop-and-go urban traffic for prolonged periods, the rear of the intake valves lacks petrol washing and easily accumulates carbon; choosing compliant products with sufficient PEA content can offer meaningful mitigation. For higher-mileage vehicles exhibiting rough idling or rising fuel consumption, clean-up additives serve as a sensible non-invasive measure once hardware faults such as worn spark plugs or faulty oxygen sensors have been ruled out.

• Realistic Limitations: Thefuel-saving effect of additives is modest. Industry benchmarks indicate realistic fuel savings of around2% to 4%, falling far short of exaggerated claims boasting "30% to 50% fuel economy improvements". Such marketing often conflates the theoretical efficiency recovered when restoring a severely choked engine to factory condition with everyday real-world savings. In most cases, the fuel cost saved does not offset the purchase cost of the additive itself. Furthermore, chemical additives cannot substitute formechanical decoking(such as walnut shell blasting); severe carbon accumulation requires dedicated professional workshop intervention.

Usage Precautions and Risks

• Not Always Necessary: For engines runningnaturally aspirated + electronic fuel injection (EFI) technology, petrol naturally washes over the intake tract during operation, making severe carbon build-up unlikely. For new cars within their initial30,000 to 50,000 km, supplemental additives are generally unnecessary provided scheduled maintenance is carried out to manufacturer specifications. Similarly, vehicles driven predominantly on open highways benefit from engine self-cleaning under sustained high-RPM conditions, making additives equally redundant.

• Application Method: It is recommended to pour the additive into the fuel tankprior to refuellingwhen the tank is nearly empty, allowing the incoming fuel rush to mix the additive thoroughly and evenly.

• Purchasing Risks: Fuel additive product quality remains inconsistent across the market. Quality spot-checks conducted by China's State Administration for Market Regulation in 2024 revealed that non-compliant brands accounted for29%of samples, with dubious formulations posing risks of engine damage. When buying, ensure the product conforms to themandatory national standard "Detergents for Vehicle Gasoline" (GB 19592-2019)and purchase exclusively via authorised retail channels. Substandard products may contain corrosive compounds, which over time will deteriorate the fuel delivery system and ruin the catalytic converter.

Policy Background (as of July 2026): In 1999, China introduced a mandatory requirement for refined petrol to be pre-blended with detergent additives; however, this statutory mandate was repealed in 2008, leaving additive usage entirely to motorists' discretion.