Diesel fuel competes with gasoline around the world, but is superior in many ways. It is simpler, no worry about octane. It is safer – a diesel spill won’t burn as easily. It has a low volatility, typically C10-C20, rather than the C5-C12 used for gasoline.
Recently, I have created a plan for a revolutionary new technique to create this useful fuel from a plentiful and completely renewable resource: wood. I discuss the methodology of this in a later post. But first, it’s important to understand why diesel is so useful as a fuel.
What is Diesel?
According to Wikipedia, diesel fuel in general is any liquid fuel used in diesels. The most common is a specific fractional distillate of petroleum fuel oil, but alternatives that are not derived from petroleum, such as biodiesel, biomass to liquid (BTL) or gas to liquid (GTL) diesel, are increasingly being developed and adopted. To distinguish these types, petroleum-derived diesel is increasingly called petrodiesel. Ultra-low-sulfur diesel (ULSD) is a standard for defining diesel fuel with substantially lowered sulfur contents. As of 2006, almost all of the petroleum-based diesel fuel available in UK, Europe and North America is of a ULSD type.
Diesel Advantages: Many people choose diesel over gasoline for its distinct advantages. Diesel does get more fuel economy than gasoline, and not by a slim margin. Diesel is more than 33% more efficient than gasoline is when it comes to your fuel mileage. This means if you were to get for example, 30 miles to the gallon, a diesel equivalent engine would get 40 miles per gallon. Diesel needs to be run through a diesel engine, and diesel engines offer more torque than a gasoline engine. Torque allows for great acceleration, which also accounts for the great fuel economy numbers. I can personally attest to these advantages: I own a diesel-running VW Jetta, and it’s the best car I’ve ever owned by a long shot!
Diesel Disadvantages (and rebuttals): Diesel engines are typically louder than gasoline engines, although technologies have been developed that have helped to limit this as much as possible. Diesel is also a dirty fuel and causes dirty emissions. (My own experience doesn’t confirm this: my car is whisper-quiet, and has no bad odor at the tailpipe).
In a straight comparison between diesel and gasoline engines, there are a number of things which can be considered. Using gasoline in cars is a mainly American tradition, as there have always been a high percentage of diesel cars in Europe. If you’re looking for a good reason not to purchase a car which runs on gasoline in the future, there are a number of cases in which diesel is much better, and more efficient.
Environmental concerns: This is the primary reason why many people choose to use a diesel car, and in this debate it certainly has benefits in both using less fuel per mile, and also making less CO2, or carbon dioxide. But the diesel fuel is not completely pollution free, and in fact has been shown to produce carcinogens, soot and NOx, which can be just as harmful to the environment – though this is not true for more recent diesel fuels. It is a good idea, then, for designers to create filters and catalytic converters for diesel engines which help to reduce even this risk of pollution, making environmental concerns a good reason to purchase diesel.
Engine performance: Surprisingly, the diesel fuel and engine combination can produce better engine performance, although this is lessened when the diesel use is bio-diesel, or other forms of enhanced fuel such as black diesel. If you intend to use the latter, then you will probably find that gasoline engines will outperform diesel cars.
Noise and smoothness of ride. This is another area where the gasoline car can easily out-do the diesel. NO MORE. While the latter no longer produces smoke under the bonnet, or horrible roaring noises, it is still louder than the gas car. You will also experience less of a smooth ride from your engine, which can make the drive a less pleasurable experience. NO LONGER.
Diesel vs. Gasoline: Diesel is becoming an increasingly popular fuel source for vehicles in the United States, and there are many benefits to using this kind of fuel, not the least of which are improvements in the performance of your engine, and a reduced pollution problem. The benefits of gasoline include a smoother movement through the engine, meaning less noise and restricted movement, and the cheaper cost of cars which run on gasoline, although it is only a matter of time before cheaper diesel cars are produced.
Diesel Fuel Economy (MPG).
Should you consider buying a diesel car? Absolutely! As part of this series, I have prepared an analysis of some of the best diesel cars on the market. But first, a look at some of the economic considerations that go into purchasing a diesel car:
There is very little difference between the two fuels in this comparison. Diesel may be cheaper than gas half the time, but for the other half it is more expensive, so they are both about the same when it comes to the price of the fuel itself. However, diesel autos get better gas mileage, so there is a saving in that direction. Gasoline cars are cheaper as new purchases, as diesel cars can be around $700 more expensive.
One of the reasons that people are buying diesel vehicles is for the diesel fuel economy. For many years, people have been driving around in diesel powered cars and light trucks for the convenience of having something that they don’t have to fill up as often. However, when you want to compare specific diesel MPG ratings you will see some startling information as to just how good diesel fuel economy is.
Fuel Economy Differs between Car Types: Fuel economy is a funny thing. Depending on the type of vehicle you’re driving, you will find different numbers. Smaller hatchbacks and sedans will deliver greater diesel fuel economy than will larger trucks and SUVs. However, when compared as a whole, you will see that the savings in both fuel and in money are much improved that just a few years ago.
Head to Head Comparison: Looking at the same sized engine, in the same size vehicle, you will be able to make a better comparison of the two types of engines, and see the real results of diesel performance. If you take into account that diesel and gas prices were the same thing, you would, over the course of a year, save approximately $2,000 in fuel costs with a diesel powered engine. There are many factors that are the reason for this, but the savings are shown in the actual results.
More Efficient: When you burn diesel fuel, there is a different dynamic happening within the engine. While there are many similarities with both engines, the main difference is the actual combustion process. This is where the economic value is. Diesel is not mixed with the air the same way that gas is. In a diesel engine the air is brought in at the top of the cylinder and then compressed greatly to where the air heats up to an igniting point. The diesel is then injected as a small mist. The super heated air ignites and the piston is pushed by the explosion. This is a much more efficient manner and does not waste as much gas by mixing the two at the beginning.
Look Deeper than Just Engine Size: One of the mistakes that people make when they want to compare regular gas to diesel powered engines is that they only look at the size of the engine. This will show you how much gas a particular engine will need, but not how well the overall vehicle will perform compared to gas mileage. You must look at the rest of the factors involved.
Savings at Purchase: The savings are not only found in the diesel fuel economy. When you buy the same vehicle-but with different engines, you will see a savings in price. A 6.0L diesel powered engine will cost you less than an 8.0L gas powered engine. Both have the same performance rating, but the diesel is going to give you a better price.
Towing Economy Diesel engines have long been used in larger vehicles because of the power of the engine and the lower cost of gas. Since diesel has escalated in price, the savings are still there, as the newer engines actually use less. It is not unusual to see more than 30 MPG on a light duty truck or SUV.
Up next in this series: a look at some of the best diesel cars on the market, and finally, the details of my revolutionary new method for turning wood into biodiesel.