The reasons why you shouldn't buy a diesel if you're going to drive in the city

In September, we learned that the automotive industry was shaken by news that flooded all the media, both specialist and general: Volkswagen had been caught falsifying the emission data of diesel engines, and it turned out that these polluted considerably more than had been believed up to that point. Shortly afterwards we discovered that it was not the only company doing so, and that many diesel engines showed worrying levels of emissions.

We have always heard that this type of engine polluted less than petrol ones, but that is only half the truth. Indeed, they emit less CO2 than petrol engines, but instead they emit solid particles, which turn out to be a very serious problem for our health. These particles accumulate in the air and can become a serious risk for everyone. In cities, of course, their presence is greater.

Diesel engines are not welcome in cities and could face restrictions on use. Driving a car equipped with a diesel engine is not compatible with urban life. These are engines designed to reach their optimal operating point when they reach a certain temperature, which is only achieved when they have been running for a certain time at a high range. In other words, urban journeys do not allow the engine to reach its optimal operating level and it does not work efficiently.

A diesel engine achieves its full performance on long journeys, where it can “open up” and deliver everything needed to obtain those results of efficiency and fuel savings. In addition, the filters that capture these solid particles also need a high temperature to work properly. If that level is not reached, they fail to do their job well and are not useful. They clog with particles, their service life decreases considerably, and they cause extra maintenance costs that are not pleasant to bear.

Diesel engine restrictions in Spanish cities

The problems that diesel engines cause in cities are very well known and notable. Madrid has faced several days in which pollution has led the city council to take measures, and it is increasingly common to read news reports in which we see how large European cities are limiting traffic in urban centres, seeking to reduce pollution.

The presence of NOx and solid particles, coming from the exhaust of diesel engines, are responsible for this pollution. The next step for municipal governments is to ban diesel-powered cars from city streets. This measure may take some time to become effective and will have plenty of fine print, but it is increasingly clear that the next enemy to beat will be cars running on diesel fuel.

One of the measures being taken by councils is to encourage the use of hybrid vehicles (which run on petrol and electric motors) in taxi fleets and urban transport. These have traditionally been diesel, since it has always been considered that they consume less and that the price of fuel has always been lower. The reality is that a diesel car only becomes more practical if more than 12,000 kilometres are driven per year. Something that falls outside the usage range of most drivers, who normally use the car for urban trips and only make long journeys a couple of times a year.

Is the diesel car finished? No, of course not. New engines offer more guarantees and anti-pollution measures, although they still have many drawbacks in the city. The arrival of hybrids and their falling prices (which are expected to keep dropping as the years pass) will gradually reduce their presence, and educating drivers with real and practical information could mean that only those who truly need the characteristics of a diesel engine will buy vehicles with one.