Advantages of Diesel Over Gasoline

Advantages of Diesel Fuel over Gasoline.

In the United States there is a major dependence on oil. A large quantity of oil is burned by vehicles which are used for personal, competitive, recreational, and commercial use, with individuals owning multiple automobiles. There are two main types of fuel used to power them, gasoline, and the superior of the two; diesel.  Diesel is widely underutilized in the U.S.  The newer engines that are powered with diesel fuel are environmentally friendly, economic, and advances have been made to improve the efficiency of diesel engines.

Petroleum oil is sometimes referred to as “black gold.” One of mankind’s most useful resources, companies spend billions to find this precious liquid.  Oil is an essential staple in the American market.  Most manufactured goods one will come across have used some amount of oil in their production.  The most significant use of oil is for automobile fuel.  “Americans burned through more than 142 billion gallons of gasoline last year- some 16 million gallons an hour. It’s an expensive habit at over $3 dollars (and 20 pounds of carbon dioxide emissions) a pop.” (Bogo)

In cars there are many engine configurations; the most popular being gasoline and diesel.  Most vehicles are created with gasoline engines, which employ electronic fuel injection technology, and have been ever since the switch from carburetors in the late 1980’s.  The electronic fuel injection technology of today allows for greater engine economy and power, mixing gasoline with the perfect ratio of oxygen.  Diesel engines, in the early years were used for more heavy duty applications, including submarines, boats, tanks, semi trucks, large scale generators, and construction equipment.  Diesels are well known for their torque. Gasoline combusts more explosively, generating high levels of horsepower.  Diesel, on the other hand, burns at a slower rate, allowing for a more thorough, complete combustion of the fuel, which releases more potential energy over a longer period of time than a gasoline burn would.  Diesel engines have a much higher compression ratio, which directly relates to their energy output; this quote emphasizes the gap between the two ratios, “Today’s gasoline engines have compression ratios of about 10:1 to 11:1, while the compression ratios in diesels can be as high as 25:1. The higher the compression ratio, the more power generated.” (Bogo)

According to this article, diesel sales in Europe are soaring, “…diesels are being purchased in huge numbers by Europeans, with diesels estimated to represent more than half of all new vehicles being sold there.” (Anderson)  American auto markets tell quite a different tale, which is evident from the higher diesel fuel prices, and the domination of gasoline powered cars.  Most Americans seek a car that can go from a complete stop to sixty miles per hour in less than five seconds, which is what gasoline engines are designed for.  Americans are always in a rush to get where they are going, and aggressive driving is on the rise.  Basically, the cars reflect the culture.

Up until the 2008 oil crisis, gasoline engines owned the market.  Hybrids had crept into the market, and diesels had long since been around, but gasoline was the choice fuel for everyone.  Limited battery technology and expensive electricity have kept electrical competitors off of the highways. When fuel prices soared to four dollars a gallon though, people began extensively researching gasoline alternatives.  Some of these fuels included using grain alcohol (increasing the cost of food), purely electric cars (increasing the cost of electricity), turning garbage into oil (demanding electricity as well), and so on.  A journal entry from the Environmental Protection Agency says it best: “The prime problem with all of these fuels was that while satisfying one need, or cutting one cost, they created another expense, which is usually greater than the cost saved by purchasing these synthesized fuels.” (Kinsey)

Advantages that diesel burning engines offer over gasoline engines include the fact that diesel vehicles are more economic and environmental in a number of ways.  The first being the most obvious; there is more energy contained in a gallon of diesel than a gallon of gasoline.  Diesel engines are reported to deliver higher miles per gallon and less greenhouse gasses, specifically, “…mileage 40% better than gasoline engines and diesel emits about 20% less carbon dioxide- the primary greenhouse gas.” (Fowler) Also, the government is willing to help, and I quote, “tax credits are available for the year you purchase a diesel, ranging from $400 to $2400.  While the price gap between diesel and gasoline is wide right now, experts predict the gap should narrow as refineries reduce gasoline production and increase diesel output.” (Motor Minutes)

In addition to less noxious fumes, diesel cars retain their monetary value, which is largely due to their less explosive combustion process.  Possibly one of the most dramatic advantages of a diesel engine is the fact that it is more adaptable to newer synthetically produced fuels.  A recent publication on this alternative fuel further illustrates this:

“It is currently impossible to pour used vegetable oil into a gas tank of a typical gasoline car and expect to go anywhere, but this is absolutely a viable fuel source for diesel engines, and people currently are running their diesel cars and trucks with recycled French fry oil; one must only filter out any food particles, water, or refuse in the oil.  Most food places will give a person their used oil for free, as it cannot be used again once it has been cooked with.”  (Gupta)

A completely free fuel source sounds too good to be true, but you can indeed run an engine purely on this food service byproduct, especially when  you have to pay for a lot more in a gallon of fuel than just the actual diesel itself.  A journal on fuel pricing says, “In a gallon of diesel, we pay for ten percent taxes, eight percent distribution and marketing, 17 percent refining, and 65 percent crude oil.”  (O’Dell) There is one major concern with this oil though.  Cooking oil cannot be left in the fuel lines.  The oil can congeal, or solidify, essentially clogging the arteries of an engine, making it unusable, and extremely expensive to repair, as the oil would be in the fuel injectors, fuel pump, exhaust organs, and engine.  The fuel lines must either be heated continuously, or the oil itself can have a chemical added to it, so as to prevent this congealing.  Also, diesel fuel itself can be added to the mix to prevent damage to the engine, switching from burning grease to running diesel through the works a few miles from the desired destination to burn off any grease left in the engine components.  Grease can also precipitate on the back end of the vehicle and rear window of vehicles burning this oil.  Depending on the engine, the fuel economy and power produced can either be reduced by running waste vegetable oil.  The only real damage that can come of utilizing vegetable oil as a fuel source is the solidifying of the fuel in the engine, or if the engine used has rubber seals, as vegetable oil is a potent solvent.

Another fact about diesel engines is that they also produce much higher torque than their counterparts, which means they can handle a heavier payload.  In a culture where the minivan has died out almost completely, and large five thousand pound sport utility vehicles and equally as heavy and more wind resistant pickup trucks are the daily commuters and family cars, torque is absolutely essential.  Gasoline engines should be left in racecars, where the abundance of horsepower and quick acceleration is of a higher priority. Many car companies, most of them foreign have been making diesel powered cars for years, and it is only now that the American companies are catching on.  To accentuate this, in 2009, two diesels were listed on Ward’s list of top ten engines.  One which came in second place and another at the bottom. The Volkswagen AG: 2.0L SOHC I-4 Turbodiesel placed tenth, and the BMW AG: 3.0L DOHC I-6 Turbodiesel, which came in second place, described by Ward’s Auto as “a powerful, sporty character, great efficiency and trick compound turbochargers make BMW’s new I-6 diesel a perfect steward of modern clean-diesel engineering.” (Murphy)  People seem to like the idea of a more powerful, sportier car that can stack up to a hybrid in a fuel economy comparison.  It is not that the consumer were not attracted to hybrids, but the fact that most hybrids were small, seeming light and unsafe, and unattractive.  Appealing to the hybrid automobile market, Ford has overcome this problem with their Escape, 36 MPG sport utility vehicle. Despite this hybrid electric victory, Diesel, with a rich past of running small sedans by Mercedes, Volkswagen and BMW remains the way of the future, as Toyota plans to release a diesel Sequoia, with Dodge and GM following close behind. 

Hydrogen fuel cell powered engines and air motorized cars may be a long way off, but the newer diesel automobiles offer a smart alternative to traditional gasoline cars or even hybrid cars, which have expensive batteries to replace, sometimes costing what the car itself would.  Since diesel is a longer standing technology than hybrids, it is also easier to get a diesel engine serviced. 

Diesels also may lead the way in the pioneering of new fuel opportunities in the struggle to free the nation from the expensive chains of foreign oil.  With rising fuel prices, a damaged environment, and a tough economy, I feel that many sensible Americans will soon open their eyes to the obvious, and come to embrace the new age of the diesel motor.  Diesel engines are indisputably supreme in comparison to gasoline engines, and will continue to draw the attention and support of the automotive and consumer communities that they deserve.




Works Cited

Anderson, Jessica. “The Payback on Diesels.” Kiplinger’s Personal Finance 63.8 (2009): 71. Academic Search Complete. EBSCO. Web. 24 Feb. 2011.

Bogo, Jennifer. “The Shape of Fuels to Come”  Popular Mechanics.  Sept 2008: pages 56-64

Fowler, Bree. “Are Americans ready to accept diesel? Cleaner burning diesel fuel prompts European automakes to push diesel-engine cars..” St. Louis Post-Dispatch 18 April 2009, 3rd ed.: A9. Print

Gupta, Ram B, and Ayhan Demirbas. Gasoline, Diesel, and Ethanol fuels from Grasses and Plants. New York: Cambridge University Press, 2010. Print.

Kinsey, John S. Evaluation of the Emissions from Low-Sulfur and Biodiesel Fuel Used in a Heavy-Duty Diesel Truck During On-Road Operation, Final Report. Washington, DC: Office of Research and Development, U.S. Environmental Protection Agency, 2009. Internet resource.

“Motor Minutes” Motor Watch.  January 2009.  p.13

Murphy, Tom.  “2009 Ward’s 10 Best Engines”  Dec 19 2008.  Feb 20 2011.

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