Conventional wisdom was that diesel was the only way to deliver significant fuel economy improvements in trucks. However, the growing emergence of direct-injected and turbocharged gasoline engines have made the fuel economy difference between gas and diesel engines much smaller than before. Seredynski said that regardless of fuel, the end goal is the same: maximum power from the minimum amount of fuel. The Ram 1500 Eco Diesel is the current full size pickup mileage champ at 20/28 mpg in EPA testing, but Ford's new 2.7L Eco Boost V-6 gas engine is likely not be far behind. Another enabling technology that has increased economy on both gas and diesel engines are transmissions with much higher gear counts, with six speeds now considered the bare minimum, just as eight-speeds and higher are starting to become the norm.
Refinement: Gas, But Barely
Diesel engines have evolved tremendously over the last 20 years in almost every area, but perhaps the most impressive strides have been made in the area of noise, vibration and harshness. In the '80s and '90s, it was not uncommon to have to turn your engine off in the drive-through so the cashier could hear your order. On some of today's trucks, the engine type is almost unnoticeable from the driver seat. The biggest enabler of this is vastly more refined injection technology, which has made diesels nearly the peer of their gasoline counterparts.
In the case of direct fuel injection, the technology has had a different effect on gasoline and diesel engines. While many gasoline direct-injection engines have a characteristic injector like that of the diesel engine. The technology has enabled diesel combustion events to get much quieter, thanks to the use of pilot injection. This reduces the sudden combustion pressure spike that's increase is what makes the disel engines sound so loud but now with these new nozzels the diesel engines are just as quite as gas. "It's interesting that common rail direct injection for diesel is used to move toward lower noise and lower emissions, to close these gaps a diesel has compared to gasoline, while direct injection for gasoline is used to close the gap a gasoline engine has versus diesel fuel economy," said Gary Arvan, General Motors' program manager and chief engineer for Duramax Diesel Engines.
Power/Torque: Decisively Diesel
Originaly power was ruled a split decision, with gasoline engines given the nod for the generally higher peak horsepower output, but diesels given the advantage for their typically higher torque figures. Today, we can fairly decisively rule in diesel's favor in the power argument, at least within the context of trucks. Yes, gasoline engines of similar displacement still have an advantage in peak power, but the gap has narrowed from 50-plus horsepower to around 20 or 30. However, the torque advantage of diesels to gas has exploded from about 80 to 100 lb-ft to about 300 to 400 lb-ft or more. What do you want when you're towing and hauling? Torque, and diesels have more of it than ever. All of the manufacturers were unanimous in their choice for diesel for frequent towing or hauling of heavy loads. 2014 Ram 3500
Cost: Pay Now, Save Later - Tie
The one area where diesels have not significantly improved relative to gas powered engines is in the area of initial cost. For the diesel engine option it still typically runs in the $8,000 more dollars then buying a gas. But dodge Ram created the EcoDiesel in their 2011 Ram 1500. Relative to thir gas base products the difference in price was only $2,850. Over the course of several years, though diesels will pay for themselves in fuel savings. Diesel fuel prices also vary wildly depending on the season, region, and even individual fuel retailer, sometimes going for less than regular gasoline and sometimes going for more than premium.
When it comes to the environmental impact that gas and diesel engines have. It turns out that gasoline is more unstable than diesel, not because of what its base consists of, but because of the additives it contains. In addition, vehicles that use diesel tend to be more fuel-efficient and produce less greenhouse gases. Diesel is more environmentally friendly. The United States has what is considered to be the dirtiest diesel, but as of June 1, 2010 this is going to be different. U.S. diesel fuel has a lower measure of ignition quality. This means that when it is cold outside, ignition performance is poor and can result in higher emissions. This is why you see truck drivers idling their trucks all night long in cold weather rather than risk a troublesome start in the mornings. But, the sulfur in the diesel that is emitted during cold ignitions and long engine idling is still harmful to the environment because the sulfurs prevent the control of diesel particulate emissions through diesel particulate filters. This is changing, though, since new advanced technologies such as nitrogen oxide absorbers are being developed to reduce these emissions. As for gasoline, it is the non-aliphatic hydrocarbons as well as carcinogenic additives that avoid engine-knocking that threaten the public's health and the environment. This exposure happens in the case of gasoline leaks and then, of course, there are the carbon emissions we hear a lot about. Leaks occur when trucks begin leaking the gasoline they are carrying, storage containers are not stored properly, and from motor vehicle leakage. Although it is determined that both diesel and gasoline have harmful effects on the environment. When we look at the carbon emissions of both, we find that diesel will emit more per gallon, but when you look at how much you have to fill the fuel tank with diesel versus how much you have to fill with gasoline, you will find that the percentage of emissions is offset for diesel, which can be friendlier on the pocketbook. On the other hand, sulfur is emitted by diesel and diesel does not perform as well in cold weather as gasoline, so until 2010 when diesel is cleaned up, gasoline may be slightly more environmentally friendly than diesel in respect to the emissions from automobiles.
Gasoline cars generally cost more to maintain over their lifetimes, but cost less per service than do diesels. Most shops charge more for hourly labor on diesel engines and parts are often more expensive as well. However, diesels have a better track record in terms of reliability and some maintenance (such as oil changes) are done less often. In the end, the average diesel car owner will likely spend slightly less than the average gasoline car owner in maintenance costs.
Diesel fuel has traditionally been less expensive than gasoline, since it was easier to refine from crude oil. However, beginning in 2004, retail diesel fuel prices have consistently been higher than retail gasoline prices. There are several reasons why. Seasonality is one factor that had always affected diesel fuel prices. Diesel fuel is essentially the same as home heating oil so In colder winters when home heating oil is in more demand, diesel prices typically climbed faster than those for gasoline .Also, beginning in September, gas demand declines, but diesel fuel demand increases as more diesel fuel is required for the machinery to harvest and transport crops. Diesel is more expensive then gas because diesel fuel isn’t just being used as fuel for trucks this fuel has many jobs
Therefore the largest difference between gas and diesel engines is that diesel engines have no spark plugs but instead compress air until it's hot, then inject fuel which ignites in the hot air inside the chamber. Diesel engines are generally stronger because of the higher-compression k. This makes the engine heavier, but is offset by simplifying much of the air intake/mixing components and electronics that aren't needed compared to gasoline injection. In terms of power, today's diesels versus gasoline engines are about the same in passenger car comparisons. Diesel excels at delivering torque while gasoline excels at horsepower. Mechanically, working on a diesel engine versus gasoline is roughly the same. Diesel engines also have fewer seals and often fewer components as well. In terms of efficiency and cost, diesel beats gasoline on most fronts. The cost on gasoline is generally lower and gas cars are often less noisy and their exhaust smells less.