Diesel vs Gas: Difference & Which Is Better?

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In the United States and the rest of North America, gas-fed vehicles are more popular. Meanwhile, diesel-powered four-wheelers comprise close to 50% of total car sales in Europe.

The fact that consumers are split between these car types signifies one of two things — either they get better performance out of their chosen vehicle, or they are wondering, “What is the difference between gas and diesel?” (and diesel vs gas engines, for that matter).

The primary differences between diesel and gasoline are their volatility, energy density, and flash point. Depending on the type of vehicle you drive and the engine it has (for instance, diesel or gas trucks), one fuel type may outperform or outlast the other.

The aftermath of these differences is what we will be covering in this guide, alongside the origins of diesel and gas and their corresponding engines. As a bonus, I will also throw in a comparison table of their many properties and highs and lows for each fuel.

I cannot promise choosing diesel over gasoline (or vice-versa) would come easily after reading this article. But I can guarantee you will leave well-informed and more confident in making the right choice!

Petrol Station Diesel and Gas Pumps

Fossil Fuels in the 19th Century

In understanding the differences and standout qualities of diesel and gasoline, it is imperative to touch on their respective origins and the beginning of their widespread commercial use. And to do this, we will have to go back to the 19th century — the period that witnessed the boom of fossil fuels.

According to historical records and studies, the use of fossil fuels dates back to the pre-Industrialization era. Coal, for one, was used in China as early as 120 B.C. and was a key element in the nation’s metallurgical industry.

Meanwhile, unrefined petroleum and bitumen were used in ancient Mesopotamia for road construction and waterproofing as early as 2,000 B.C.

As for diesel and gasoline, they came to fruition much later — during the 2nd Industrial Revolution (otherwise known as the Progressive Era), to be exact. This period spanned from 1870 to 1920, with its last few years overhanging the onset of WWI.

The fact that the discovery of gasoline and diesel preceded the First World War had a major influence on how these energy sources were utilized by the world moving forward.

Gas vs Diesel

Mid-to-late 1800s saw the advent of gasoline and diesel. However, people did not immediately realize their value during their discovery. At the time, existing fossil fuels already had roles to play in the grand scheme of things.

Coal was everyone’s main heat source and the muscle behind the steam engine, while kerosene was used for lighting.

Gasoline — A Discarded Byproduct of Kerosene

As the primary fuel used for lamps, there was naturally a high demand for kerosene during the second half of the 19th century. However, kerosene is not a raw fossil fuel and had to be harvested by refining crude oil (a process pioneered by Samuel Martin Kier).

The separation of kerosene from other hydrocarbon compounds was made possible through simple fractional distillation — a procedure where crude oil is heated in a vessel at around 600° C, and vapors resulting from varying boiling points are condensed into liquid fractions. Subsequently, this process gave birth to naphtha (a forerunner to present-day gasoline).

Unfortunately, oil refineries of old found little to no use for gasoline and either burned the fuel or threw it away. This went on for quite some time.

It was not until the last decade of the 19th century that gasoline was considered a valuable fuel. Demand for crude naphtha rose significantly.

This paradigm shift is all thanks to the invention of petrol-fed ICE or internal combustion engine (more on gasoline engines later).

Diesel — Sharing a Similar Fate

Diesel (formerly distillate fuel oil) is made from crude oil and biomass. Like gasoline, it is another byproduct of the fractional distillation of kerosene and was initially deemed useless by oil refineries.

It was not until Rudolf Christian Karl Diesel invented the compression-ignition engine or diesel engine in 1892 that manufacturers and consumers found a good use for this less-volatile fuel type.

Although diesel shared similar circumstances with petrol at the point of discovery, it became prominent and gained widespread commercial use a tad later than the latter. The reason behind this is not that diesel is inherently more sulphuric and pollutant than its counterpart but that the diesel engine design had to be finalized before distillate fuel oil could be tested on it.

Historical records report the use of diesel fuel in commercial vehicles dates back to 1893. But in truth, only prototype testing commenced in the said year.

It was not until four years after at Maschinenfabrik-Augsburg AG (or Maschinenfabrik-Augsburg-Nürnberg) that successful testing took place, with distillate fuel oil demonstrating a 26.2% efficiency with the compression-ignition engine.

Perfecting Refining Processes

Because of the increasing demand for gasoline and diesel for automotive use, geniuses from different refineries had to improve the dated distillation process initially used to extract kerosene from crude oil. Hence began left and right experimentations.

William Burton and Robert Humphreys doubled oil refining efficiency by subjecting crude oil to high heat and temperatures and successfully coming up with ‘thermal cracking.’

Similarly, Eugène Jules Houdry painstakingly took refining processes a step further by fine-tuning ‘catalytic cracking.’ This process utilized specific silica and alumina-based catalysts to produce an even greater gasoline yield from crude petroleum than the 40% Burton and Humphreys had already managed to achieve.

Platforming

But the biggest breakthrough in crude oil refinery (and chemical engineering in the past century) happened four years after Houdry’s contribution. In 1941, visionary Vladimir Haensel pioneered ‘platforming’ — a refining process using small amounts of platinum on alumina support as a catalyst to produce high-octane, efficient-burning gasoline without using lead or TEL as an additive.

This refining process is so revolutionary that it inspired catalyst regeneration and birthed more advanced procedures like houdryforming and rheniforming.

This feat paved the way not only for higher petrol Octane ratings but also for the eradication of leaded gasoline and the introduction of the catalytic converter. More than 85% of the world’s gasoline supply is derived from more recent iterations of platforming.

A few attempts to develop new technologies to yield gasoline and improve efficiency were initially successful but proved detrimental in the long run. One example is Thomas Midgley’s discovery of TEL or tetraethyl lead (a lead-based fuel additive) in 1921 while researching engine knocking at Dayton Research Laboratories.

Other Fuel Refining Processes

Except for fractional distillation, all other diesel fuel refining processes differ from gasoline.

  • ‘Vacuum or atmospheric distillation,’ for example, is a more advanced distillation method that permits the production of low-sulfur diesel from high-sulfur crude oil.
  • ‘Hydrotreating’ is a procedure that lowers sulfur concentration in straight-run diesel to an acceptable limit of 15 ppm.
  • Finally, ‘hydrocracking’ breaks down hydrocarbon molecules into smaller chains to manipulate diesel fuel’s flashpoints, compression resistance, and Cetane rating.

Overall, the above refinery processes were (and still are) successful in yielding large volumes of gasoline and diesel to satisfy demand. Furthermore, they led to interesting petrochemical byproducts.

One such outcome is butadiene found in “feedstocks,” which later gave way to the production of plastics (a hydrocarbon compound that helped in the proliferation of post-war consumerism and a topic for another day).

Diesel Engine vs Gas Engine

Jeep Gladiator Side View

The development of diesel vs gas engines was born out of necessity more than finding a use for the then newly-discovered energy sources. Initial renditions of the internal combustion engine (ICE), in particular, were designed to address drawbacks linked to the steam engine.

Although the high-pressure engine improved transportation and set the Industrial Revolution in motion, it offered low thermal efficiency. The steam engine was also hefty (which made it inconvenient to operate) and had a power unit separate from the mill.

Gas Engine Architects

Hence, an engine design with a self-contained power unit became increasingly appealing to industrialists and manufacturers. Consequently, inventors and engineers built engines with configurations geared toward this objective.

Early attempts at creating prototypes of ICE began in the 17th century. Of all these endeavors, the 1860 Lenoir engine was the first to succeed, becoming the forerunner of 2-stroke engines.

Though successful, Jean Joseph Étienne Lenoir’s creation was far from perfect and had only limited power output enough for printing presses and water pumps. This shortcoming seemed to have prompted French Engineer Alphonse Beau de Rochas to publish the principles of the 4-stroke engine in 1862 and German Engineer Nikolaus Otto to actually build an engine following Rocha’s theoretical advance 14 years later.

Other notable men of science are credited with the first gasoline engine. Among them are Gottlieb Daimler and Wilhelm Maybach, who developed the first high-speed 4-stroke engine with a gasoline-fed carburetor used on bicycles and carriages. The other is Karl Friedrich Michael Vaillant Benz, who built the first single-cylinder gasoline motor in 1879.

Rudolf Christian Karl Diesel

While several names line up behind the invention of gasoline engines, there is only one such person for diesel engines — Rudolf Christian Karl Diesel.

While the general concept of the diesel engine is intertwined with gas-fed power mills (since both are internal combustion engines), Diesel went against the grain by having heat from compressed air ignite the fuel inside the engine instead of a spark.

His hypotheses immensely influenced this decision that higher amounts of compression equal higher efficiency and power. And he was absolutely right, as this significant change in ignition made diesel engines superior to gasoline engines in the topic of diesel vs gas efficiency.

Naturally, some inventors challenged Rudolf Diesel in pioneering the compression-ignition engine. Among them were German entrepreneur Emil Capitaine and Richard Hornsby & Sons of England.

Neither was successful in discrediting Rudolf Diesel for his work, as the latter’s engine design was more straightforward and did not employ a fuel-sprayed pre-chamber (among other variances).

While gasoline and diesel engines were considered advanced concepts in the 19th century, they still held a lot of promise. Later-century visionaries exploited these potentials, transforming gasoline and diesel power mills into what they are today.

(Tip: Thought Co. and the Universal Technical Institute are great online resources if you want further reading on gasoline and diesel developments following their inception and commercial success.)

Diesel vs Gas Comparison Table

ParameterGasolineDiesel
Shelf Life1 month (in an equipment fuel tank), 3 months (at 30 °C), 6 months (in a tightly sealed container at 20 °C), or 1 year (under shelter and in an untampered, sealed container)at least 1 year (under cover and in a sealed container), 6—12 months (under other circumstances)
Compression RatioBetween 8:1 and 12:1Between 14:1 and 25:1
Flash Point-43 °C (-45 °F)Between 52 °C and 93 °C (or 125 °F and 199 °F)
Thermal Efficiency (according to Toyota and MDPI)20—36% (gasoline engines)40—47% (diesel engines)
Ideal RatingAt least 87 Octane (PON) or 91 RONAt least 45—55 Cetane level
Fuel Blendup to 10% ethanol or E10 gasohol, up to 15% MTBEB5 (5% biodiesel, 95% petroleum diesel), up to 15% ethanol for e-diesel blends
Ambient Temperature-40 °C to -73 °C (freezing point)0 °C (freezing point), -12 °C (gelling point), 149 °C to 371 °C (vaporization)
Engine Life Expectancy120,000—150,000 miles200,000—300,000 miles
Affordability (as of 09 Jan 2023)$0.938/liter or $3.551/USgal$1,202/liter or $4,550/USgal
ApplicationPassenger cars, motorcycles, boats, recreational vehicles, construction and farming equipment, power generators, small aircraftGeneral automobile market, commercial trucking, public and school buses, tractors, cruise ships, heavy equipment, power generators

Diesel vs Gas — Pros and Cons

ParameterGasolineDiesel
AdvantagesWorks well with most light vehicles and motorcycles; produces cleaner emissions; has a better burning rate; has easier cold starts due to high volatility; produces less noise and vibration than diesel engines.Runs at much slower RPMs; only requires an alternator, thus eliminating ignition tune-ups; more efficient on highways than gas-fed engines; high torque makes for better acceleration and fuel economy.
DisadvantagesHigher volatility point; higher cost of fuel; requires spark plugs for ignition; shorter engine life expectancy; low fuel efficiency and resale value; bad fuel mix may lead to engine malfunction.More expensive; emits approx. 13% more carbon dioxide than gas; requires extensive repairs and maintenance; enhanced diesel products tend to have a negative impact on vehicles.

Conclusion — Diesel vs Gas: Difference & Which Is Better?

Person Holding Gasoline Nozzle

Even after detailing fuel histories and lowdowns in this guide, there is still no definitive approach to determining which fuel (between diesel and gasoline) is better. Several factors could make one option appear more favorable than the other — mobility needs, engine longevity, and budget concerns included (to name a few).

Disparities in costs and performance of these fuels and their respective engines may have been apparent in earlier years. But as oil refinery and automotive technologies constantly evolve, these differences will only continue to narrow in the future.

Let us also not forget stricter emissions and environmental regulations pushing the phasing out of some of these fuels sooner than expected.

Hence, opting for one fuel type over the other will be entirely up to you. The same goes for choosing the better engine.

Ultimately, energy density and long-term expenses will be consequential to making your choice, as well as your vehicle make and model, driving habits, and location.

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