Diesel is a petroleum-based fuel, derived from the same crude oil as gasoline. When distilled, the lighter fuel becomes gasoline and the heavier fuel is made into diesel. Because diesel is denser than gasoline, it provides more energy, or specifically better fuel economy, per gallon. But it does also have some drawbacks. Here’s look at the pros and cons of diesel fuel:
Diesel fuel is more efficient
When it comes to fuel economy, diesel-powered cars go far. Indeed, up to 30 percent farther per gallon of fuel.
Biofuel use is possible
Unlike some gasoline engines, many diesel engines are designed to run on biofuel. Typically this involves B20 biodiesel, composed of a blend of 80 percent straight diesel and 20 percent organic-based fuel. Biofuel is cleaner burning, but it also is less efficient than straight diesel.
Diesel engines last longer
Diesel engines are composed of more robust parts than gasoline engines, in a bid to handle the higher compression ratios and heavier fuel required. The upside here is that these engines can last about twice as long as a comparable gasoline engines.
Maintenance is simpler and cheaper
Diesel engines don’t come with spark plugs or a distributor, parts that must be replaced on gasoline engines according to the vehicle’s maintenance schedule. Diesels offer higher twisting force. Twisting force or torque is a form of power produced by engines and most noticeable when climbing a hill or pulling a heavy object, such as a trailer. Diesel-powered vehicles offer optimum torque and superior trailering capabilities.
Diesel fuel costs more
Pull up to most any service station pump that sells both gasoline and diesel, and the cost of diesel is usually higher than gasoline. One reason for the difference is that the federal excise tax for diesel is 24.4 cents per gallon, but just 18 cents per gallon for gasoline.
Diesel fuel pollutes more
Diesel fuel has a higher level of secondary organic aerosol, a major component of smog. Although diesel-powered vehicles, including commercial trucks, represent only a small portion of the vehicles on the road, they generate a higher concentration of Secondary Organic Aerosols (SOA) than gasoline-powered cars.
Cold weather makes for a harder start
When temperatures drop below zero degrees Fahrenheit, diesel-powered cars are more difficult to start. Such engines require higher temperatures to ignite the fuel. However, a simple workaround is to invest in a block heater to keep the engine warm when the vehicle is not in use.
Diesel vehicles are louder
If you place a premium on a quietly operating vehicle, a diesel-powered model will always be louder, although sound-deadening materials may mitigate some of that noise.
Choose a diesel-powered model and you’ll pay more for that vehicle than one comparably powered by a gasoline motor. A total cost of ownership paper released by the University of Michigan Transportation Research Institute in 2013 comparing gasoline and diesel models, found that this premium ranged from a few hundred dollars for select Mercedes-Benz models to more than $10,000 for select heavy-duty pickup trucks used chiefly for commercial purposes. However, the resale rate for such models is usually higher, enabling owners to recoup their investment.
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Photo courtesy of Wikimedia Commons.
Matt Keegan has maintained his love for cars ever since his father taught him kicking tires can be one way to uncover a problem with a vehicle’s suspension system. He since moved on to learn a few things about coefficient of drag, G-forces, toe-heel shifting, and how to work the crazy infotainment system in some random weekly driver. Matt is a member of the Washington Automotive Press Association and is a contributor to various print and online media sources.