EU5 and EU6 engines, what’s the difference?

With news of the diesel emissions scandal littering the internet, you might have seen mentions of EU5 and EU6 engines. What exactly are they, how do they compare to one another and what parts have they played in the recent controversy?

For more information on today’s emissions standards, check out our guide to Euro 6 (or EU6) engines. You could get a great deal on a huge range of new cars sporting EU6 engines using our car configurator.

What are EU5 and EU6?

EU5 and EU6 describe regulations put in place by the European Commission to restrict emissions from petrol and diesel vehicles. Their introduction has forced manufacturers to invest in developing cleaner-burning and more efficient engines.

Since EU1 was introduced in 1992, efforts have been concentrated on reducing the levels of Carbon Monoxide and Dioxide (CO and CO2), Hydrocarbon and Nitrogen Oxides (NOx) and particulate emissions (like soot). In recent years, further regulation has helped to curb the emission of volatile organic compounds – thought to be dangerous to human health – into the atmosphere.

The effect of these new rules has been profound. Since 2000 the average CO2 emissions of passenger vehicles in grams per kilometre has fallen by a whopping 28 per cent.

So is there any difference between EU5 and EU6?

Yes and no. EU regulations for vehicle emissions vary between diesel and petrol cars because of the different ways they work. Diesel cars are more prone to heavy particulate and NOx emissions, while petrol cars tend to pump out more carbon monoxide and dioxide gases.

EU6 regulations for petrol engines have remained mostly the same as EU5 but diesels are now more heavily restricted than they were six years ago, especially with regards to Nitrogen Oxide emissions.

Petrol emissions (g/km)
Emission type EU5 (2011) EU6 (2014)
Carbon Monoxide 1.0 1.0
Nitrogen Oxides 0.06 0.06
Particulates 0.005 0.005
Diesel emissions (g/km)
Emission type EU5 (2011) EU6 (2014)
Carbon Monoxide 0.5 0.5
Nitrogen Oxides 0.18 0.08
Particulates 0.005 0.005

‘Dieselgate’ scandal

Designing diesel engines to meet EU5 and EU6 regulations meant fuel economy and vehicle performance were slightly affected in some cases. Some manufacturers, most notably those in the Volkswagen-Audi group, found a way to cheat the system and seemingly offer the best of both worlds.

Because of the way vehicle emissions are tested, car makers found it was possible to engineer a car to perform one way on test but differently on the road. Regulatory bodies such as the European Commission would be satisfied the car didn’t emit too many dangerous chemicals, and drivers would experience greater fuel economy and improved performance.

In some extreme cases, diesel vehicles were found to emit more than ten times the amount of NOx that’s legally permitted.

Is my diesel car safe to drive?

If you own a car that has been affected by the emissions issues mentioned here, you’ll be contacted by a dealer who will outline any attention you car may require. It is worth noting, however, that your car is still safe to drive on the road. Equally, the Government has confirmed that you won’t be liable to pay any more tax if your car is found to be polluting more than advertised.

Save money on your new car

Although there has been controversy regarding some diesel cars, there is still a huge range of fantastic new vehicles to choose from. Our car configurator can help you to get your ideal car for a great price. If you’re not sure what to buy, our deals pages and car chooser tool are here to help.

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