Why Diesel Cars Are Disappearing

Diesel fuel was once promoted throughout the world as a readily available solution to increasing fuel economy. Diesel engines were praised as heavy-duty, hard-working, fuel-sipping engines, excellent for some of the toughest jobs and heaviest machinery: hauling, scraping dirt, and driving long distances. Their reputation for efficient and long-lasting engines made them a popular choice throughout Europe, one of the largest automotive markets in the world. They were supported by government incentives and adopted by major automakers. For a time, it looked like

diesel

engines might be one of the best technologies available for achieving ambitious fuel economy goals. Then the

diesel

case seemed to fail.

Cities where diesel engines were common struggled with extremely high levels of air pollution. World health authorities determined that diesel fuel is carcinogenic. In 2015, German automaker Volkswagen, one of the world's largest car companies, shook the industry when executives admitted that the company had cheated on diesel emissions tests. The executives were fired and imprisoned. Volkswagen was forced to pay billions in fines and payments, and some wondered if the scandal meant the beginning of the end for diesel engines themselves. At the same time, hybrid and electric vehicles increasingly became, for many, the best new hope for providing low-emission or even emissions-free transportation and equipment.

But diesel advocates say diesel isn't over yet. It is still widely used in heavy machinery and commercial applications. Companies are developing new technologies such as pollution filtering systems and renewable biofuels that could keep diesel relevant and widely used for years to come, including as solutions to reduce toxic emissions. Within the truck market, diesel plays an important role in terms of the number of vehicles we produce with diesel, certainly heavy duty. And there is a constant desire for more capacity. The diesel engine is named after its creator, Rudolf Diesel, a son of Bavarian immigrants born in Paris.

Diesel was an engineer who worked in refrigeration technology during the day. But in his spare time, he entertained ideas for a more efficient engine than the typical designs of his time. He designed an engine that functioned similarly to conventional internal combustion engines, but with some crucial differences. In an internal combustion engine, diesel or not, fuel and air are combined inside a cylinder chamber where they burn. The explosion pushes a piston, which turns a crankshaft and ultimately turns the wheels that move a vehicle. In a typical gasoline engine, a spark plug ignites the air-fuel mixture inside the cylinder.

But Rudolf Diesel determined that no spark was necessary. His design simply compressed the air in the cylinder to the point that the air was so hot that it would cause the fuel to burn. As soon as it was injected into the cylinder. The basic design innovations of diesel are still seen in today's diesel engines. The design of the diesel engine gives it some of the advantages so appreciated by enthusiasts. Diesel engines tend to get better fuel economy than gasoline engines, sometimes much better. And they can also deliver a lot of power to the wheels at low speeds, making them great for heavy machinery and vehicles that need transportation, whether they're freight trucks, construction equipment, or trains.

Diesel fuel is also different from gasoline and is more energy dense, meaning that more energy can be extracted from diesel than from the same amount of gas. Diesels achieve, on average, around 30 percent more energy efficiency than a comparable gasoline vehicle. So that comes from two things. The fuel itself has more energy potential and then the engine burns that fuel more efficiently. So, those two things together make diesel the most energy efficient internal combustion engine. Over time, their fuel-saving potential made them highly desirable options in countries where governments were trying to reduce carbon emissions. Lower carbon dioxide emissions were one of the reasons the European Union began boosting the fuel in the 1990s.

Around that time, climate change became a serious global issue and countries began signing major global carbon reduction agreements, such as the 1997 Kyoto Protocol. For a long time, during most of the 1990s and early 2000s, and in many countries in Europe, diesel was the majority and represented the majority of sales of light vehicles. In some markets, such as Italy, diesel engines reached 90 percent of the market. And Germany and France were also very popular. But that, in North America, diesel was never that successful, except during periods when we tended to have very high fuel prices. However, diesel engines have their drawbacks.

While diesels are good with low-end torque, it's easier to get higher horsepower out of a gasoline engine. That's why diesel engines are typically found in large trucks and heavy machinery, but rarely in sports or racing

cars

. There have been other drawbacks that eventually gave diesels a bad reputation that they still struggle with today. In general, diesel engines produce less CO2 than gasoline engines, which is helped by the fact that they burn less fuel. However, they produce higher concentrations of other dangerous pollutants, especially nitrogen oxides and very small particles, commonly known as PM 2.5. European countries that adopted diesel saw it as a trade-off.

Sacrifice some losses in air quality in exchange for gains in CO2 reduction. Many European countries implemented tax advantages to encourage the adoption of diesel engines. These incentives caused sales of diesel

cars

to skyrocket throughout Europe. But over time, cities like Paris showed signs of dangerously high pollution. European emissions standards have restricted pollutants such as nitrogen oxide since at least the 2000s. But for years laboratory tests were easy to exploit. As the European Environment Agency noted in a 2019 report. In 2012, the World Health Organization said it considered diesel exhaust gases to be carcinogenic. Several studies over the years have shown harmful levels of nitrogen oxides and other pollutants in European cities, often well above legally permitted limits.

Perhaps the biggest blow to diesel's reputation was the cheating scandal that rocked Volkswagen and other automakers starting in 2015. The German automaker, one of the world's largest, had invested heavily in diesel fuel and had marketed for its fuel economy benefits. But starting in 2015, revelations began to emerge that the company had installed software in cars designed to manipulate emissions test results. These defeat devices were able to recognize when a car was being tested in a laboratory, rather than being driven in real-world conditions, and thus calibrate the engine to fool the test by temporarily producing emissions low enough to meet regulations.

Once on the road, cars equipped with these devices often released pollutants that far exceeded legal limits. Volkswagen has had to pay approximately $35 billion since 2015, in addition to penalties, fines, settlements and other payments. The scandal appears to have marked a turning point in Europe's history with diesel. After the Volkswagen scandal, diesel sales fell drastically in Europe, although it was still more profitable to drive a diesel engine there. It has dropped significantly. Our own statistics, globally, between 2016 and 2018, while overall vehicle sales and electric vehicle sales increased globally by about one percent. Diesel sales fell about nine percent globally in that same period.

Of course, in Europe, where diesel was most popular, it fell the most. In 2015, the proportion of diesel in new passenger cars in Europe was around 51 percent. In 2018, that proportion had fallen to 36 percent. This is the lowest percentage of total new car registrations since 2001, according to industry data firm JATO Dynamics. The association with the notorious VW scandal damaged the reputation of diesel. But perhaps even worse was the talk among European politicians of completely banning internal combustion cars, including diesel, in major cities. The United Kingdom said in 2020 that it plans to ban the sale of new diesel and gasoline cars by 2035.

France also plans to end the sale of internal combustion cars by 2040. Car makers such as Volvo and Nissan have said they plan to reduce their quota of diesel vehicles or phase them out completely. In the wake of the scandal, VW took a rather sharp turn toward electrification. The company said in December 2019 that it planned to produce one million electric cars by 2023, ahead of the 2025 target it had previously set. Of course, there's hardly an automaker in the world that isn't dabbling in electric vehicles. This poses real competition for diesel engines; Even larger vehicles, such as buses and delivery trucks, can run well with electric and hybrid powertrains.

Invading the territory that diesel once had practically to itself. Local vehicles, such as garbage trucks and buses, are increasingly moving toward electric drivetrains. Local authorities are buying many more electric buses because they are cleaner, quieter, more efficient and cheaper to run. Companies like Amazon, which operate huge fleets of delivery vehicles, say the FedEx, UPS and Amazon vans that deliver all your packages traditionally run on diesel engines. But you know, that's starting to change now. Amazon invested $800 million last year in an electric vehicle startup called Rivian. And UPS and FedEx are doing it... they're also buying a lot more electric vans.

So for local operations where those vans return to a depot at night, it's easy to plug them in and charge them overnight. It's not a great deal. For now, diesel is still everywhere. Most farm equipment in the United States runs on it. It is still very common in heavy construction, mining, shipping and shipping and much of public transport. Although companies like Tesla are venturing into long-haul electric trucks, diesel remains the propulsion system of choice for that sector. The last place you're likely to see diesel is in long-haul trucks, where it remains a challenge. It takes a lot of battery in those things to go electric.

You know, they're driving, you know, thousands of miles across the continent, and it's going to be a while before they're electrified. But, you know, emissions, diesel emissions, are less of an issue because they tend to be more present in rural areas when you're driving across the country. While diesel emissions are not... where they are a bigger problem is in urban areas. So, urban local delivery vehicles are going electric. Long-haul vehicles will still be diesel for a while yet, but probably in the late 2020s, we will start to see them go electric too. Diesel advocates say it's too early to rule out the fuel and there may be more opportunities for growth.

Companies are developing technology that can reduce the emission of harmful pollutants that have previously caused problems for diesel. All diesel sold in the United States is ultra-low sulfur diesel, which is a form of fuel that contains a small fraction of the sulfur contained in older forms. This fuel allows diesel vehicles to be equipped with new pollution-reducing devices. Today we know that around 43 percent of all registered and operating commercial vehicles on the country's roads are of the latest generation of diesel. That means they have the full suite of particulate control and advanced selective catalytic reduction systems, diesel exhaust fluid, etc., allowing them to achieve near-zero emissions.

Companies are also investing in biofuelsrenewable, which are refined from crops or organic waste. Many diesel engines can now use a blend of 20 percent renewable fuel and 80 percent petroleum-based diesel, commonly called biodiesel, but known more technically as B20. Some go even further and use fully renewable fuels and diesel engines. The city of San Francisco converted its municipal vehicle fleet to fully renewable diesel fuel. Advanced renewable biofuels, such as biodiesel, have made it possible to reduce the carbon footprint of a diesel engine from an additional 20 percent, to up to 80 percent, if more refined and advanced processing of those biodiesel feedstocks is used.

Diesel also appears to have returned to some key segments that are especially popular with American consumers and profitable for American automakers: trucks and sport utility vehicles. Diesels provide greater efficiency and greater autonomy. And with a light diesel, you can drive from Duluth to Dallas on a single tank of fuel, compared to gasoline: 35 miles per gallon on the highway. And if you look at the torque curve, the torque curve is very low RPM. In 2019, all three American automakers had, for the first time in years, at least one full-size, half-ton diesel pickup truck in their product lines. Diesel engines are also options in midsize trucks like the Chevrolet Colorado.

And General Motors offers diesel engines in its Chevrolet Suburban and Tahoe sport utility vehicles. Those trucks and some great options for those who really like off-roading and Jeeps. Both the Wrangler and Gladiator have diesel engine options in those vehicles. That's why we get a lot of grunts from those who actually do true off-roading. The low-end torque of the diesel is something that segment really likes. So I think there are big opportunities for diesel in the light vehicle segment in these larger vehicles and these high-performance veterans. Much of the automotive industry is betting that the future is electric.

But the bridge to all-electric cars, trucks, trains and construction equipment could be a long one. The diesel industry is betting that consumers and governments will want effective solutions they can implement along the way.