Diesel Gas Mileage
While semi-trucks, heavy equipment trucks, and other larger type vehicles have always used diesel gasoline, today more and more cars are being designed to also run on this type of fuel opposed to regular gas. There are a number of reasons for this change, which will be discussed in this article. Although choosing a diesel powered vehicle may not be for everyone, many people prefer this type of engine.
Keep in mind that when light trucks were first introduced for everyday use some 10 years ago numerous challenges existed. For one thing, these engines produced an unpleasant smelling exhaust, the engines were loud, sometimes the trucks vibrated, and for automobile manufacturers, the cost to build them was outrageous. However, vehicles with diesel engines today are very different although there are still positive and negative aspects that should be understood prior to buying.
We wanted to provide a comparison between engines that operate on diesel fuel and those that run on standard type gasoline. To become educated about differences, as well as learn the ups and downs associated with diesel engines versus gas engines, the following would prove helpful.
Power versus Torque & Gas Engines versus Diesel Engines
To begin, both experts and consumers feel the level of power for diesel engines and gas engines are pretty much equal but there are distinct differences.
Vehicles that operate on standard gasoline do have more horsepower although those that operate on diesel have greater torque. Therefore, if the vehicle would be used to run errands or drive short distances, and if it would not be used for to pull a trailer, boat, camper, and so on, better power would be provided with a gas engine.
These engines are built to rev up faster, allowing a higher RPM peak to be achieved. As a result, gas powered vehicles can reach larger horsepower numbers and are a faster choice for o to 60 MPH driving.
If pulling power was most important when purchasing a new vehicle, then torque produced by diesel engines would be a better option. In addition, these engines are capable of going up steep grades more efficiently with or without pulling a load. The high-compression ratio required to ignite this type of fuel is 17 to 1 whereas for standard gas engines, the ratio is only 9 to 1.
Because of this, torque and power for this type of engine are produced within the lower rev range. In simple terms, an 8.1L V8 engine operating on regular gas produced 340 horsepower and 455 pounds per foot of torque while a 6.6L V8 turbo engine running on diesel provides 300 horsepower but a significantly higher torque of 520 pounds per foot. In fact, there are now diesel powered trucks on the market that produce 365 horsepower and 765 pounds of torque per foot.
Engine Efficiency & Gas or Diesel Engines
Another comparison is efficiency, which is very important for most people in the current economy. Obviously, people want a nice vehicle and one that provides the level and type of power needed but without spending a fortune.
Gas engines contain approximately 125,000 BTUs while diesel engines contain 147,000 so to produce the same level of power, a gas powered engine would require more fuel. Therefore, when looking at fuel burned on a per gallon basis, diesel engines are more efficient.
The level of efficiency for both gas and diesel engines is based on design. For instance, diesel fuel goes directly into a fuel-injection system whereas gas has to be mixed with incoming air in the intake manifold. As a result, the amount of fuel that goes unused or even wasted fuel would be less for diesel engines. In fact, the amount of fuel used while idling would be about 33% less for a diesel engine than a gas engine.
According to experts, miles per gallon for larger trucks such as three-quarter ton, yield can reach up to eight times greater than for a truck of the same size running on regular gasoline. Although this type is substantial regardless, for the person who drives long distances, cost savings would be tremendous over the life of the vehicle.
Fuel Efficiency and Cost
vAnother consideration would be diesel gas mileage in comparison to mileage for vehicles that use standard gasoline, as well as the cost to fill the tanks of both vehicles. Typically, a diesel engine burns less fuel than a gas engine because of the higher combustion temperature, but also the greater expansion ratio. In most cases, newer gas powered vehicles have a 24% efficiency rate, which means that approximately 25% of fuel energy converts to mechanical energy. For newer diesel powered vehicles, this increases to 30%.
The cost of fuel for a diesel engine is greater than fuel for a gas engine although this has not always been the case. In fact, for a long time fuel costs were much the same and sometimes less. Although there were different reasons, one had to do with federal taxes whereby diesel fuel has a tax rate of 6% while regular gasoline is taxed at 18.4%. However, with demand for diesel powered vehicles growing, gas companies have found a way to increase prices at the pump, which is why diesel fuel is higher than gasoline fuel in today’s market.
Looking at this comparison historically, a set pattern could be followed but since 2004, things have changed. While the dollar amount a person pays for regular gasoline varies for each state and gas station, on average the cost is $3.79 a gallon. The same applies for diesel fuel but cost averages higher at $4.50 a gallon.
We have also seen changes in formula and quality of diesel fuel, primarily due to new standards being established by the Environmental Protection Agency. One example is the sulfur content of diesel fuel, which as of 2006 had to be reduced dramatically from a maximum of 500 parts per million to a maximum of 15 parts per million. New standards as of 2010 demand that all diesel powered vehicles on the road must comply.
The bottom line pertaining to fuel efficiency for the two types of engines is that when in top working condition, a diesel engine could get upwards of 50 miles per gallon opposed to 30 miles per gallon for a vehicle running on standard gasoline. When properly cared for by a skilled diesel mechanic, reaching 400,000 miles on a single engine or even 500,000 or more is possible whereas most gas engines only last to about 200,000 miles.
Other Important Differences
Several differences exist between the two types of engines, with some of those discussed in this article. While both engines have internal combustion, the way in which the combustion is achieved is what separates the two. For instance, direct ignition, which involves fuel vapor being lit by a spark, is the way in which a gas engine achieves combustion. On the other hand, compression is the primary method for combustion in diesel engines is achieved.
In addition, diesel engines acclimate to different climates and damp environments easier than gas engines because they are not designed with a high-tension electrical ignition system. Not only would this reduce the cost of work performed by a professional diesel mechanic, without a complex system to include wires, coils, and so on, interference of radio frequency emissions is prevented, allowing communication and GPS equipment to work properly.
Even the life of a diesel engine is much longer than a gas engine. Although different factors would dictate the lifespan of both engines, with diesel powered vehicles, engines usually last 50% longer or more.
Vehicle Repair and Safety
Along with performance, there are also things that people should know when comparing gas engines to diesel engines. The following are a few of the more important considerations.
- Whether driving a vehicle with a gas or diesel engine, having repairs done would simply be a part of ownership. However, fuel used in diesel engines has higher quality lubrication properties, which can prevent certain types of repair issues to be avoided.
- Regular gasoline is highly flammable that could prove life-threatening in certain situations. For example, if a diesel mechanic was working on a vehicle that operates on standard fuel and a spark was created, risk of explosion would be high. In the same token, a bad accident with gasoline leakage would pose serious danger. However, in open air diesel fuel does not burn so while still potentially dangerous, certain risks would be avoided.
- Vapors have always been a concern for the environment and health of the human population to the point of strict laws being created and enforced specific to emissions. Although diesel fuel does release some level of flammable vapor, the amount is much less than fuel from a gas powered engine.
- The amount of waste heat in connection with exhaust and cooling is usually less in diesel engines
- With gas engines, boost pressure is limited by pre-detonation whereas in diesel engines, only the strength of components would have an effect
- There are many environments such as underground mines in which only diesel engines could be used due to low carbon monoxide exhaust being released
- For people who support a healthy planet by using recyclable substances, there is a definite advantage in owning a diesel powered vehicle. Unlike gas engines, diesel engines can operate on biodiesel fuel, which comes from old grease tossed out by restaurants and fast food chains