The future of Diesel. What is the fate of compression-ignition engines?


Passenger cars with Diesel engines have been rapidly losing in popularity on the new car market in recent years. Clients prefer electric and hybrid vehicles over them. What is the future of Diesel?

Diesel: from flourishing to falling in 40 years  

As recently as the 1980s, Diesel engines were mainly used in Europe as propulsion for utility vehicles. After Diesel engines appeared in the offers of German manufacturers, such as Volkswagen or Audi, they slowly started gaining popularity. In 1990, they made up 13.8% of all first registered vehicles in Western European countries. In the subsequent years, due to a political decision, the focus was shifted to the CO2 emission as the proverbial whipping boy in terms of ecology. Diesel engines are more efficient than gasoline ones, which is why on paper they pollute less, at least when it comes to carbon dioxide. All of that caused an increase in popularity for diesels and in 2006 their share in the “old” European Union countries exceeded 50% for the first time. The peak was reached in 2011, when passenger cars with diesel units constituted whole 55.7% of all new cars registered in the 15 wealthiest EU countries.  In the subsequent years, this trend got reversed, and by 2020 the percentage of diesels in registration of new cars was only 28%, whereas in the 1st quarter of 2021 it dropped down to 23.2%.     

Drop in popularity of Diesel engines  

Diesels in the passenger car segment are a phenomenon that outside of Europe is only present in India. On all the other major passenger car markets – in USA, China and Japan – pretty much all cars are equipped with gasoline, hybrid or electric engines. In recent years, however, the popularity of Diesels dropped in western Europe. Whereas as recently as 2016 their share in the new car market was 49.5%, by the end of the 1st quarter it dropped to just 23.2%.  

There are several factors that contributed to that:  

  • the announcements of bans on entry of Diesel engine cars in major European cities, especially in Germany 
  • the increasing consumer awareness and numerous scientific studies showing the negative impact of diesel fumes on health (i.e. increase in asthma cases) 
  • the growing popularity of hybrid cars, in which the most common internal combustion unit is a gasoline one, as well as other alternative propulsions, including the electric    

Economical Diesel  

The main factor, however, is still the economy. Complying with the increasingly stricter exhaust emission standards is getting more and more expensive for the automotive companies. In the very price-sensitive city and compact segments, where annual mileages are usually relatively low, the customers are unable to accept higher costs of buying a car. That’s because there is no way it could be paid back in form of lower costs of gas at annual mileages of up to 10 thousand km. It’s a vicious circle.  

There are voices saying that the days of Diesel in passenger cars are already numbered, but it’s still rather a fairly distant prospect. Outside of city and compact cars, where everything is pointing to diesels being soon pushed away by hybrid units (internal combustion & electric ones, with the former being the gasoline type), in all the other segments there are no signs of that. In the middle class, or even in SUVs, where high mileages are nothing out of ordinary, there won’t be an alternative to the compression-ignition unit for a long time when it comes to the dynamics and costs of use.     


In modern gasoline engines, it is becoming more common to use soot filters. Widespread use of direct injection, the ever shrinking capacities (the so-called downsizing, which is reducing the engine capacity in order to comply with tight exhaust emission standards) and turbochargers as well as increasingly strict emission standards – all of that is causing a necessity in the newest units to install soot filters (GPF – a counterpart of the DF in diesel engines). Right now it’s not a major issue, but in just a few years the problem-free models on the secondary market may mostly include hybrids and cars with non-overused gasolines engines, preferably without turbo, direct injection and the above mentioned GPF.