Fleet News

Euro6: Diesel cleans up its act

Euro6 emissions regulations will see all car and van manufacturers introduce super-clean diesel engines. But how are they achieving the new standards and what will it mean for fleet operators? Sarah Tooze reports.

Diesel has traditionally been seen as a dirty fuel, but EU emissions regulations are helping it to clean up its act.

What is Euro6?
Euro6 more than halves the amount of nitrogen oxides that a diesel car can emit with a cap of 80mg/km. The EU is focusing on NOx because it is one of the most harmful greenhouse gases. It can last up to 150 years – significantly longer than other greenhouse gases.
Euro6 will be binding for the type approval of vehicles as of September 1, 2014, and for the registration of new types of cars and vans as of September 1, 2015.

The regulations cover a wide range of harmful emissions: carbon monoxide (CO), non-methane hydrocarbons and total hydrocarbons, nitrogen oxides (NOx) and particulates (PM).

The aim is to reduce these emissions, thereby limiting the impact on the environment and public health.

Diesel is a bigger culprit than petrol when it comes to these emissions – although it emits less CO2 (not measured by Euro6 as there are separate targets for manufacturers).

Euro4 standards, which were introduced in 2006, saw diesel engines make big strides in reducing the amount of harmful emissions they produce. It would take 35 Euro4-compliant vans to produce the same volume of particulates as one pre-Euro1 vehicle, for example.

The current Euro5 standard took things further, limiting the amount of NOx a car can emit to 180mg/km – a 20% reduction compared to Euro4. But Euro6 is more ambitious.

A number of manufacturers are ahead of the game and already have Euro6-compliant cars and vans on the market.More were unveiled at this month’s Geneva Motor Show.

Meeting Euro6 is relatively straightforward for petrol engines. Ford, for example, will expand the use of its Ecoboost powertrain across more vehicles.

Diesel engines present more of a challenge.

Mazda was one of the first manufacturers to introduce a Euro6 diesel engine. It says its Skyactiv technology has allowed it to improve the cleanliness of its diesel engines without the need for exhaust after-treatment systems.

This has been achieved though weight reduction, reduced compression ratio and more efficient drivetrains.

However, most manufacturers are turning to after-treatment systems such as the Lean NOx trap (which is fitted instead of the normal oxidation catalyser) and the Selective Catalytic Reduction (SCR), which works with a reduction agent (Adblue).

Bosch claims that its Adblue Denoxtronic system can reduce nitrogen oxide emissions by up to 95%. It is a more expensive system than the Lean NOx trap but Bosch says Denoxtronic can help reduce fuel consumption by up to 5%, which offsets the higher cost.

The system isn’t required on small cars, since optimised combustion is sufficient to meet the European NOx limits, so it is generally found only on larger cars, SUVs, and commercial vehicles.

Leave a comment for your chance to win £20 of John Lewis vouchers.

Every issue of Fleet News the editor picks his favourite comment from the past two weeks – get involved for your chance to appear in print and win!

Login to comment


  • James - 25/06/2014 12:13

    Great to see harmful emissions being reduced once again. Additionally to the cost of AdBlue, Fleets will need to be mindful that vehicles fitted with 2 catalytic converters will double the risk of catalytic converter theft, as well as potentially doubling the cost of replacement. Seeking out information on suitable solutions to protect vehicles from this type of theft is straightforward and can be found through the vehicle manufacturers / Dealers themselves.

  • Mr.Bean - 09/07/2014 16:13

    Euro6 will increase costs for most users and in most cases the driver. Leasing companies will in most cases pass the cost of top ups between services to the end user. Also, the cost of the vehicles is much higer vs a current Euro5, in some cases over £1000. For me this is another key change to ensure drivers move away from diesel to petrol. Many many drivers out there are doing no more than 12k per year and are driving diesel vehicles. Can I also add that some are able to meet the Euro6 without the need of adblue, these will gain more business once drivers are aware of the tru cost of running a car with adblue. Some manufacturers will need a top up every 6500 miles, I guess most are not aware of this.

  • Colin Mill - 25/10/2014 15:52

    According to the following report the technology employed to comply with Euro 6 is failing spectacularly - by a factor of about 7 - to achieve the standard in real-world situations. See http://www.theicct.org/sites/default/files/publications/ICCT_PEMS-study_diesel-cars_20141013.pdf

Compare costs of your company cars

Looking to acquire new vehicles? Check how much they'll cost to run with our Car Running Cost calculator.

What is your BIK car tax liability?

The Fleet News car tax calculator lets you work out tax costs for both employer and employee