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Diesel Pickup Trucks Pros and Cons



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Diesel pickup trucks are a very good choice for a number of reasons, with few cons. Most of the problems that diesels had in the past have been resolved in newer vehicles, the new light-truck diesels are far quieter, cleaner, and powerful than in the past due to many technological advances.

Pros:

1. One of the most important advantages diesels have over equivalent gasoline engines is the efficiency of the diesel engine. Diesel engines are 20-40% more efficient than gasoline engines. This is due to the way diesels operate In a diesel, the engine draws air into the cylinders, compressing it, then injecting fuel into the combustion chamber where the intense heat caused by the compression ignites the mixture. Gasoline engines draw air and fuel into the cylinder then ignite the mixture with an electrical spark. The diesel's design allows (and requires) a very high compression ratio, which allows nearly all of the fuel injected to be burnt. This gives you more power, better emissions, and better mileage from a diesel over an equivalent gasoline engine. New technologies making their way to light truck diesels, such as turbo-charging and computer controls, are allowing even better efficiency and power.

Diesel is the most efficient of all internal combustion power systems. Because of the superior efficiency of the engine and higher energy content of the fuel, diesels generally deliver 20-40% more miles per gallon of fuel, and emit 10-20% fewer greenhouse-gases than comparable gasoline vehicles. According to the EPA, the Volkswagen Jetta can travel 36 percent more miles on a tank of fuel and save $321 per year on fuel, while using almost two fewer barrels of oil each year. The 2007 Mercedes E320 Bluetec diesel and it's E350 gasoline equivalent finds even greater savings. The diesel model can travel 43% more miles on a tank of fuel and saves $492 annually on fuel costs while using 3.2 fewer barrels of oil each year.

An example of better efficiency in diesel powered light trucks compared to gasoline powered light trucks is the 2008 Ford Powerstroke diesel versus the 6.8L V10 and 5.4L V8 gasoline engines. The Powerstroke makes 350 HP and 650 lb.-ft of torque, while the V10 makes 362 HP and 457 lb-ft and the V8 makes 300 HP and 365 lb-ft. Also, diesels make all of their power low in the RPM range, the Powerstroke makes peak torque at just 2000 RPM, which is great for towing and hauling. The Powerstroke gets an average 21.5 MPG, compared the the V8 and V10 at 17 and 12.5 MPG, respectively. All of this is from similar 7000 pound F-350 Super Duty, as the EPA doesn't publish mileage ratings for heavy-duty trucks.

The lower horsepower ratings in diesels compared to gasoline engines is due to the lower red-lines that diesels have. Because a gasoline engine can reach 6000 RPM or more, it produces more horsepower. Horsepower is calculated by the formula HP = (torque * RPM) / 5252. If the Ford Powerstroke diesel were able to reach 6000 RPM, it could theoretically make approximately 750 HP.

2. Diesel pickups have far more durable power- and drive-trains. Diesel engines generally last 250,000 miles before requiring a rebuild, and well maintained engines can last even longer, compared to gasoline engines which are only expect to last 100,000 miles, although most modern gasoline engines can last to 200,000 miles or more with proper maintenance. Many diesel enthusiasts don't even consider a diesel fully broken-in until 100,000 miles, due to the over-built nature of the diesel engine. Drive-trains usually include stronger transmissions and drive axles compared to gasoline pickups, due to the increased power output and potential of the diesel engines. This allows for higher weight ratings for towing and hauling, as well as fewer costs in maintenance and repair.

3. Diesel engines can be run on alternative fuels with little or even without any modifications, diesels were originally designed to to run on peanut oil. Currently available bio-diesel can be run in a diesel with no modifications at all, while straight vegetable-oil, or SVO, can be used in a diesel from a separate tank that includes a small heater and a valve to switch between standard (petroleum) diesel or bio-diesel, and the SVO, or mixed with a solvent such as kerosene in order to thin the oil to a viscosity close to petroleum diesel.
While not widely available commercially at this time, bio-diesel can be made at home with little investment and very low cost. Bio-diesel and SVO also burn very cleanly, considerably reducing emissions without considerably sacrificing mileage. In a study published by the EPA, they found that a diesel run on 100% bio-diesel, had a reduction of 67% in unburned hydrocarbons, 48% in carbon monoxide, 47% in particulates, but an increase of 10% in NOx emissions. There was also a reduction of some non-regulated emissions, Sulfates are completely eliminated, and the ozone potential of speciated hydrocarbons was cut in half. Mileage is reduced only slightly, 5% lower versus petroleum diesel, compared to the 30%+ reduction seen with E-85 ethanol in gasoline engines.

Cons:

1. The most major concern most consumers have is the noise made by diesel engines. While diesels are generally noisier than gasoline engines, they have been getting much quieter in the past 15-20 years. Diesels are loudest at startup, and quite considerably as they warm up, usually with several minutes. Most modern diesels, such as the 2008 truck diesels from Dodge (Cummins), Ford (International Powerstroke) and Chevrolet (Duramax) are only slightly noisier than any of the gasoline engines available in these trucks.

2. Another concern is emissions. While diesels produce less carbon dioxide and little or no carbon monoxide, they have, in the past, produced large amounts of oxides of nitrogen (NOx) and particulates. These have been extremely reduced in the past few years through the use of particulate filters, selective catalytic reduction (SCR) similar in function to catalytic converters on gasoline vehicles, and ultra-low sulfur fuels.

3. The third concern is the availability and cost of fuel. This is not a problem in rural areas and near highways, but can be an issue in more urban areas with few diesel cars and trucks. It is a good idea, before purchasing a diesel truck, to take a drive around your area to see which, if any, stations carry diesel fuel. While diesel is available everywhere in the US, less than half of the fuel stations carry diesel. If you are having a hard time finding a station that carries diesel, the best place to look is near major highways and areas with a lot of semi traffic. The price of diesel is generally higher than gasoline, but the higher efficiency usually makes up for the difference



Diesel pickups may not be the best choice for everyone, but they make a lot of sense both economically and environmentally. They are more efficient, longer lasting, provide more power, and are alternative-fuel ready from the factory. In the near future, truck manufacturers will begin offering small diesels in half-ton and mid-size trucks instead of forcing you into a heavy-duty pickup in order to reap the benefits of diesel technology. There are some cons to every engine type available today, but with diesels, the pros far outweigh the cons.

Sources:
Diesel Technology Forum
http://www.dieselforum.org/fileadmin/templates/FactSheetMasterFolder/ClimateChangeBrochure_SCREEN.pdf

About.com
http://autorepair.about.com/cs/generalinfo/a/aa102001a.htm

Grassroots Biodiesel and Vegetable Oil Fuel Homepage
http://www.dancingrabbit.org/biodiesel/

The National Biodiesel Board
http://www.biodiesel.org/

More about this author: Mark Hamburger

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