Diesel vs. Gasoline – a Brief Guide to Their Pros & Cons Amidst the Volkswagen Dieselgate Scandal

Diesel and gasoline pump nozzles 1 photo
When problems overwhelm and sorrow smothers, where does Volkswagen find the will and courage to keep on keeping on? It will be up to a Winterkorn-less Volkswagen and its enraged board of directors to answer that question. Us folks, on the other hand, are more concerned with the advantages and disadvantages of diesel fuel compared to gasoline. Which is the better fuel, which is the more efficient, and which poses the greater health and environmental risks? These are the questions we will happily answer for those of you concerned with the hysteria surrounding the ongoing Dieselgate fiasco. For this little piece of writing, we have tried to put the light on the good, the bad, and the ugly sides of diesel and gasoline as factual and veridical as possible, without any bias toward the octane rating or cetane number. Because this comparison and this TDI Clean Diesel scandal fit with some of The Prodigy's best-known tunes like a jigsaw falling into place, we will split this guide into four distinct components: Firestarter for history, Diesel Power for diesel, Fuel my Fire for gasoline, and Poison for the health and environmental effects of both. Now let's get going with chapter #1. Firestarter
Gasoline was not invented per se. After a gentlemen going by the name of Edwin Drake dug the first oil well in 1859, he then distilled the crude oil to produce kerosene. But the distillation process saw the creation of other petroleum products as well, including gasoline. At the time, Drake had no use whatsoever for the gasoline and any other product coming from the fractional distillation of petroleum except for kerosene. This begs the following question: how did dinosaur juice came to the attention of oil companies? And why?

It's simple – by the time Karl Benz rolled out the Benz Motorwagen in 1886, gasoline still wasn't in demand. Approximately two decades after the invention of the first gasoline-powered automobile, the first gas station opened in St. Louis by Automobile Gasoline Co., a subsidiary of Shell of California.

At the time, a fill-up consisted in the shopkeeper filling a five-gallon can from behind the store and bringing it to the customer's car to fill it. By 1908, there were 300,000 cars on the roads. With the introduction of the Ford Model T the same year, automobile sales skyrocketed, bringing gasoline into focus.

To this day, gasoline is still more popular than diesel fuel. Diesel was ignored as garbage for more decades than gasoline. Believe it or not, diesel fuel was thrown away as a byproduct of fossil oil refining for more than 40 years since it was discovered.

Etymology-wise, diesel has been first used as an adjective in 1894 after the word was borrowed from Rudolf Diesel's last name and one of his revolutionary engine designs. Some say that the coal industry's head honchos murdered the German inventor because his engine blueprint was modified to use diesel fuel instead of powdered coal, posing a big problem for steam engine locomotives and the coal industry.

Within two decades of the compression-ignition engine's invention in 1892, diesel power was being applied to trains, ships, tractors, and ships. In Anno Domini 2015, diesel cars make up roughly half of new car sales in Europe while the engine technology has a mere 3 percent share in the traditionally diesel-hostile USA.

Diesel Power

On a molecular level, diesel fuel contains more carbon atoms in longer chains than gasoline. Furthermore, diesel is cheaper to produce and it takes less refining than gasoline, which is sort of surprising (if not utterly scandalous) considering that diesel is often the more expensive choice at the pump.

The financial interests of the biggest companies in the industry might have something to do with the absurd pricing of diesel, though, because gasoline-powered automobiles and trucks consume more fuel than their diesel-powered counterparts.

Thanks to its heavy carbon chain, diesel has a higher energy density than gasoline – 40.8x106 Joules per 1 liter of diesel compared to 34.7x106 Joules per 1 liter of gasoline. In plain English, diesel produces higher thermal energy than gasoline. Still, there's a drawback due to the extra torque.

We all know that diesel engines are made stronger than gasoline motors. This increases weight of important components. At any speed, a diesel engine is considerably more audible than a gasoline motor, vibrations included. This is because there are no spark plugs to ignite the fuel in an oil burner. Rollin' coal is done solely by compressing the fuel-air mixture until the diesel ignites by itself in the cylinder.

The lack of spark plugs is a problem when it's cold and the air isn't hot enough to ignite the fuel under compression. In terms of "Suck, Squeeze, Bang, Blow," you could say that the diesel engine sucks. As a general rule, diesel mills are more expensive to manufacturer and service, partly due to the higher compression ratio, another reason people all over the world buy sensibly more gasoline-powered cars.

While you do get more torque from a diesel motor, the torque band is narrower than that of a gasoline engine. Oh, nearly forgot about this one: engines powered by Satan's fuel clatter like farm tractors.

Fuel my Fire

Gasoline is lighter than diesel fuel, the main reason it evaporates faster and it's more flammable. Compared to the narrow torque band of diesel-fed motors, gasoline engines deliver the goodies at higher revs and on a broader torque curve. Needless to say this but burning gasoline also produces much more melodic sounds than the agricultural clatter coming from diesel.

While gasoline engines don't get the same mileage and torque as their diesel counterparts, you do get something else – horsepower. A sensible way to differentiate torque from horsepower is the following – top speed is given by horsepower (and gearing) while acceleration mostly depends on the torque produced and the way torque is delivered by an engine. Simple as that.

A further difference between gasoline and diesel is that gasoline performance is measured via the octane rating (the higher the octane, the more compression the fuel can withstand before igniting) while diesel performance is measured via the cetane number (an indicator of the fuel's combustion speed).

Because gasoline engines don't have to cope with the same stress levels as diesel engines, they are cheaper to make and cheaper to fix. What these two types of fuel have in common, though, is the horrific short to long-term effects on health and the surrounding environment, the focal points of chapter #4.


Volkswagen's emissions scandal is no laughing matter, but people tend to point the finger at diesel without knowing how this fuel pollutes compared to gasoline. Euro 6-compliant diesel engines emit less carbon dioxide (CO2) than gasoline-fed engines, but the gasoline motor has an advantage in terms of mono-nitrogen oxides (NOx) emissions. How do these two invisible poisons sicken us and the environment?

Even though gasoline is now unleaded, at least a dozen hazardous chemicals occur in various amounts during and after the combustion process. Benzene and antiknocking additives are the most carcinogenic. According to the World Health Organization, 2.9 percent of deaths in 2012 are attributed to lung, trachea, and bronchus cancers. That translates into the fifth leading cause of death in the world, killing more than 1.6 million people. On a lighter note, diarrhea killed 1.5 million people in 2012, a comparable death toll to the one attributed to HIV and AIDS.

CO2 is an asphyxiant gas, getting people drowsy and giving us a stuffy feeling in our lungs. Environmental-wise, the biggest concern with gasoline is the photochemical smog that comes with unburnt gasoline and evaporation from the fuel tank. Because it is heavier than air, CO2 can also collect in pocketed locations below average ground level. Animals and children have died because of this. Carbon oxide is the most harmful of greenhouse gases.

It is considered to be the greatest concern among greenhouse gases (such as methane, ozone, nitrous, and so forth), because it exerts a larger warming influence than all other gases combined and because it has a long atmospheric lifetime. Still, don't think for a moment that diesel is the lesser bad just because it emits less CO2 than gasoline.

Scientists agree that NOx gases coming from diesel soot cause more warming than CO2 in the first decade after emission into the atmosphere. However, as pointed out before, the CO2's global warming effects last longer than those attributed to NOx gases. It's a matter of short-term and long-term damage here, but one this is certain – exhaust fumes coming from diesel engines (including NOx) are silent and deadly.

Have you stood next to a running diesel engine-powered car in an underground parking lot? If you did, you certainly have sensed the distinctively unpleasant smell of diesel exhaust gases. It's as nasty as it gets.

The issue with NOx is that it reacts with some of the most common organic chemicals, including moisture and ammonia. In worst case scenarios, compounds produced by NOx in the atmosphere may cause biological mutations. In the presence of sunlight, NOx forms ozone, causing adverse effects such as lung tissue damage to children, the elderly, and asthmatics. Compared to the global warming effect of CO2, NOx emissions represent one of the main causes of global cooling.

Through the formation of OH groups that destroy methane molecules in the air, NOx counters the effects of greenhouse gases. However, we deem necessary to mention that global temperature is only the first measure of the extent of climate change attributed to NOx emissions.

Whatever the future holds for diesel after the Volkswagen Dieselgate scandal cools off (no pun intended), think about the environment and your children more than about mileage when buying your next family car.

Editor's note: do you happen to know the best NOx joke around? It's intoxicating (*ba dum tss*).
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About the author: Mircea Panait
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After a 1:43 scale model of a Ferrari 250 GTO sparked Mircea's interest for cars when he was a kid, an early internship at Top Gear sealed his career path. He's most interested in muscle cars and American trucks, but he takes a passing interest in quirky kei cars as well.
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