Why Don’t Cars Use Kerosene?

Cars don’t use kerosene because it doesn’t match how modern car engines are designed: spark‑ignition (gasoline) engines need a highly volatile, high‑octane fuel that kerosene isn’t, and diesel engines need a high‑lubricity, controlled‑cetane fuel that kerosene doesn’t consistently provide. The result is hard starting, knocking or rough running, higher emissions, and potential damage to fuel pumps and injectors—plus regulatory and infrastructure hurdles.

Fuel chemistry vs. engine design

Most cars run either spark‑ignition (gasoline) or compression‑ignition (diesel) engines. Gasoline engines ignite a well‑vaporized, premixed charge with a spark and therefore require high octane and high volatility; diesel engines rely on autoignition from compression heat and therefore require predictable cetane quality and good fuel lubricity for high‑pressure pumps and injectors.

Kerosene—chemically a “middle distillate” akin to jet fuel—sits between gasoline and diesel. It’s less volatile than gasoline and typically lower in lubricity than diesel. Those traits make it misaligned with both mainstream automotive engine types.

The following points outline the technical mismatches that keep kerosene out of passenger car fuel tanks.

• Gasoline engines: Octane and knock. Kerosene has very low octane (it’s not even rated in automotive terms), so in a spark‑ignited engine it tends to pre‑ignite and knock under load, risking piston and bearing damage.
• Gasoline engines: Volatility and cold start. Gasoline is formulated to vaporize readily (Reid vapor pressure roughly 7–15 psi seasonally); kerosene’s vapor pressure is typically under 1 psi and its flash point is far higher (about 38–72°C vs. gasoline at around −43°C). That makes cold starts and proper mixture formation difficult, leading to misfires and stalling.
• Gasoline engines: Emissions control mismatch. Heavier, less volatile hydrocarbons increase particulate and unburned hydrocarbon emissions, especially at cold start, undermining three‑way catalyst efficiency and evaporative‑emissions calibration.
• Diesel engines: Lubricity and hardware wear. Modern common‑rail diesels rely on the fuel for pump and injector lubrication. On‑road diesel is additized to meet lubricity limits (HFRR wear scar ≤460–520 μm). Jet‑grade kerosenes typically fail this, often exceeding 700 μm without additives, which can scuff pumps and stick injectors.
• Diesel engines: Ignition quality variability. While some kerosenes/jet fuels have cetane indexes around the low‑40s, on‑road diesel targets higher and more consistent values (about 45–55; EN 590 in Europe specifies a minimum 51). Lower/variable cetane lengthens ignition delay, causing noisier, rougher combustion and higher NOx/PM unless the engine is calibrated for it.
• Both engine types: Calibration and additives. Road fuels carry detergents, corrosion inhibitors, conductivity and anti‑icing/lubricity packages tuned to automotive systems and emissions aftertreatment. Kerosene’s additive slate (or lack of it) is different, and not designed for car catalysts, DPFs, or SCR systems.

Taken together, kerosene’s low volatility, low octane, and low lubricity mean it neither behaves like gasoline in a spark‑ignition engine nor like specification diesel in a modern compression‑ignition engine.

What happens if you try it?

In a gasoline car

Expect hard or no starts, stumbling idle, misfires, and heavy knock under load. Unburned fuel can wash cylinder walls and dilute oil, and prolonged knocking risks mechanical damage.

In a diesel car

The engine may run, but pump and injector wear can accelerate quickly without added lubricity. Cold‑start performance and idle quality may suffer, and emissions can spike. Limited winter blending of kerosene into diesel is practiced in cold regions to lower cloud point, but it’s done with proper additives and within manufacturer limits.

History and narrow exceptions

There are a few specific contexts where kerosene has been used, but they rely on different engines or special procedures.

These examples show when kerosene can work—and why those cases don’t translate to everyday cars.

• Early tractors and stationary engines: Some started on gasoline and switched to kerosene once the intake manifold was hot enough to vaporize it (“tractor vaporizing oil”).
• Multi‑fuel military diesels: Built to tolerate kerosene/jet fuel with reinforced pumps, adjusted injection timing, and dedicated additives.
• Gas turbines (jet aircraft): Continuous‑combustion turbines favor kerosene for its energy density, low freezing point (Jet A‑1 around −47°C), and safer handling; their combustion process differs fundamentally from piston engines.

These niche uses depend on engine designs, operating procedures, or environments unlike those of modern passenger cars, which prioritize cold‑start reliability, low emissions, and long component life.

Economics, infrastructure, and regulation

Even if technical hurdles were solved, kerosene faces practical barriers. Retail distribution for road users is limited; automotive fuel standards don’t certify kerosene for on‑road use; and taxation schemes often dye non‑road fuels. Using dyed kerosene on public roads is illegal in many jurisdictions. Emissions certification and onboard diagnostics are calibrated to gasoline or diesel specs, not kerosene.

Could kerosene ever power mainstream cars?

Technically, yes—with purpose‑built compression‑ignition engines and tailored fuel chemistry—but it would look and behave like a diesel vehicle, while offering little advantage over modern ultra‑low‑sulfur diesel. Today’s development focus favors cleaner diesel, renewable diesel, synthetic e‑diesel/jet fuels, and electrification, all of which integrate more readily with existing standards and aftertreatment systems.

If one were determined to make kerosene viable in cars, the following changes would be required.

• Engine architecture: Use compression ignition with injection timing and pressure optimized for kerosene’s ignition delay.
• Fuel system: Hardened high‑pressure pumps/injectors plus lubricity additives to meet diesel‑grade wear limits.
• Cold‑start aids: Glow plugs, intake heaters, or fuel vaporizers to compensate for low volatility.
• Aftertreatment: DPF and SCR systems calibrated for kerosene’s combustion products, with compliant sulfur/aromatic content.
• Fuel specification and supply: A road‑legal kerosene grade with mandated lubricity, detergency, and emissions‑friendly additives, plus distribution at retail.

By the time those changes are made, the result is essentially a diesel vehicle running a diesel‑like fuel—eliminating any compelling reason to choose kerosene over certified automotive diesel or its renewable equivalents.

Summary

Kerosene doesn’t power cars because it’s a poor fit for both major engine types: it’s too low in octane and volatility for gasoline engines and too low in lubricity and ignition consistency for modern diesels. The penalties include hard starts, knocking or rough running, higher emissions, and hardware wear, alongside legal and infrastructure obstacles. Where engines and procedures are engineered around it—such as turbines, military multi‑fuel diesels, or historical tractors—kerosene can work, but those cases don’t translate to today’s road cars.

Did cars ever run on kerosene?

In Europe following the Second World War, automobiles were similarly modified to run on kerosene rather than gasoline, which they would have to import and pay heavy taxes on.

Why is kerosene used instead of gasoline?

Storing large amounts of kerosene is relatively safe compared to gasoline or propane, as it is less volatile and does not easily ignite. In conclusion, kerosene is an excellent choice for off-grid living and emergencies, providing a dependable and affordable source of energy for cooking, lighting, and heating.

Why use kerosene instead of diesel?

Compared to diesel, kerosene is less expensive. The former is subject to tax & duty due to its use in automobiles and other industrial machinery. However, kerosene is a lighter oil unsuitable for road vehicles. But, it rather suits home heating and cooling systems.

Why was kerosene a bad choice for fuel?

Kerosene has a very low octane rating and is unsuitable for use in engines having anything much higher than a 4:1 compression ratio (all modern engines). Added to gasoline, kerosene extensively reduces octane rating and will clause ‘detonation,’ which can result in severe engine damage.