Euro 6 – Understanding the new regulations

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Euro 6 FeatureThe major significance of the Euro 6 regulations for diesel cars is a major squeeze on controlling the emissions of oxides of nitrogen, or NOx as they are termed.

This comes as a result of further evidence of the health risks of urban air pollution specifically related to NOx, and a disappointing reduction in cities like London, where NOx pollution remains stubbornly high.

The new limits are slashed from the Euro 5 limit of 180 milligrammes per kilometre to just 80mg/km. It takes effect for all newly introduced models from September of this year, and all cars from September 2015. In addition, a year later, effective from September 2017, new systems of On-Board Diagnostics (OBD) that manage all the engine emissions warning lights and fault recording will have to be updated to reflect the tighter limits and monitor the new systems involved.

Car manufacturers have come up with varied ways of meeting the tighter Euro 6 NOx limits. The challenge has been to either reduce the production of NOx at source well enough to avoid other more costly measures, which is quite difficult, or to post-process the NOx-rich exhaust gases to reduce the level below the Euro 6 limits, effectively by one of two different ways. Manufacturers may employ different methods in different cars in their ranges, and in some cases the same engines may use different methods in different car models, depending on their power output and weight.

Exhaust Gas Recirculation (EGR) is a key player in reducing NOx emissions, and is based on replacing some of the air in the intake gases with recycled exhaust gas, mostly carbon dioxide. These gases replace some of the nitrogen that comprises 80 per cent of air, thus reducing the amount of nitrogen available to be oxidised to NOx during combustion. Engine conditions that cut NOx emissions tend to increase particulate emissions, and vice-versa, which further adds to the difficulties. NOx reduction at source, without any need for further exhaust processing to reduce NOx, has in some engines been achieved by clever engineering of EGR systems, whilst Mazda has reduced the compression ratio of its new SkyActiv engines (to just 14:1) to reduce combustion temperatures and, along with EGR and variable exhaust valve lift, are meeting Euro 6 limits without any further treatments.

The second method, involving destruction of NOx in the exhaust system, employs proven NOx storage technology, where a catalytic converter stores generated NOx in certain engine conditions and then, in short fuel-rich periods, the nasty stuff is released and reduced to harmless nitrogen over a catalyst. Other similar systems involving temporary NOx storage and intermittent destruction are used by several manufacturers, such maintenance-free NOx treatment techniques being generically termed NSR (NOx Storage Reduction) or LNT (Lean NOx Traps.)

The third method of NOx control, called Selective Catalytic Reduction, is a system using injected Diesel Exhaust Fluid (DEF), or commonly known as AdBlue, stored in a separate tank in the car. The active additive component, urea, reacts to neutralise the NOx in the exhaust gases. SCR is well-proven technology and has been used in heavy commercial vehicle engines for some years. SCR, where the NOx is only processed at the end of the exhaust system, also has some benefits in that exhaust gas NOx reduces the temperature at which accumulated DPF particulates burn off, reducing blockage problems and there may even be scope for further developments where NOx is specifically targeted at keeping DPFs clear of soot, using the NOx and soot to destroy each other. SCR also holds out the promise of delivering marginally better fuel consumption than the alternative systems.

We may find that Euro 6 emissions regulations can be met with either improved EGR systems, or NOx storage and later processing on many smaller vehicles, while most higher-powered vehicles may require costlier SCR technology, which may in fact offer superior fuel economy to NSR. But the maintenance-free systems are seemingly nearing limits of effectiveness, and those adopting additive-based SCR may be better placed if even lower NOx emissions limits come with Euro 7, and will be well disposed for today’s North American market, where tougher NOx limits are already in place.

On the horizon though, we also have the prospect of new emissions and fuel consumption test cycles, and the threat of Portable Emissions Measurement Systems (PEMS) that may be used to do on-the-spot emissions checks. And, dare we say it, systems that might automatically restrict your engine’s operation, and maybe even performance, to ensure that its emissions are kept within the legal limits; maybe not so much the “limp-home” mode that you can get when your engine’s ECU starts playing up, but possibly “amble-home” when your engine is told that it’s kicking out too many pollutants. Welcome to the wonderful world of Euro 6!

Whats Hot:

• Cleaner running means a lower number of particulates entering the atmosphere.
• Lower CO2 emissions means lower rates of taxation.
• Better fuel economy results in cheaper running costs.
• For company car users, lower CO2 emissions means less benefit-in-kind taxation.
• Euro 6 marks the removal of the two per cent loading on diesel engines for company car drivers.

Whats Not:

• The technology costs money to install, which is then passed onto the customer in higher purchases prices.
• SCR equipped cars will need the AdBlue fluid topping up at service time.
• Greater complexity means higher repair costs when the items need replacing further down the line.

Web_Audi - 2Audi

Already Audi is ahead of some of its rivals, with the entire A3 range (Hatchback, Saloon, Sportback and Cabriolet) and A8 luxury saloon meeting the tougher emissions regulations. Its range of ‘ultra’ models meet them, too, in A4, A5 and A6 guises, with the upcoming facelifted A7 and all-new TT guaranteed to be compliant too. The A3 meets the standard using LeanNOx trap technology, while all of the other models feature selective catalyst reduction, combined with an AdBlue additive. Audi says that by the time the 2016 model year cars are introduced, in May 2015, every Audi in its line-up will be capable of meeting the tougher Euro 6 standards.

Web_BMW 4 Series Gran CoupeBMW

It’s a gold star for BMW, with a significant number of BMW’s model range are already fully compliant with the latest regulations, with any new products launched, and there have been a significant number, all meeting the tougher new standards. BluePerformance editions of the 1 Series, 3 Series, 7 Series and old model X6 already meet the Euro 6 criteria, as does the new 2 Series Coupé and Active Tourer, 335d xDrive, 3 Series GT (except 318d), 4 Series, 5 Series, facelifted X3, new X4 and X6 and the X5. That just leaves the non-Blue Performance 1 Series, 3 Series and 7 Series, as well as the X1 and Coupé, Cabriolet and Gran Coupé versions of the 6 Series to be updated. And with almost all of the engines available in a Euro 6 specification already in other models, it won’t be long until the entire BMW model range can boast of its Euro 6 eligibility.


There aren’t any models in the Chrysler and Jeep line-ups that meet the Euro 6 standards, however, the company says “they will continue to work to the new requirements as set out by the EC within the time frames, in the reduction of vehicle emission output”.

Web_Citroen (2)Citroën

Already Citroën has begun the roll out of BlueHDi engines, meeting Euro 6 regulations and all featuring selective catalyst reduction. The C4 Cactus has a BlueHDi 100 engine from launch, and the DS5 has had BlueHDi 120 and 180 units since late last year. The updated DS3 will include both BlueHDi 100 and 120 engines from next month, with 2.0-litre BlueHDi 150 editions of the C4 Picasso and Grand C4 Picasso already available. The new regulations will mean the death of the 1.4-litre HDi engine, which will be replaced by a new 1.6-litre Blue HDi 75 model, with the Citroën range progressively updated from now until May 2015 when the entire range will be compliant.


There aren’t any models in the Fiat line-up that meet the Euro 6 regulations, however, Fiat says it fully intends to comply and will announce changes to the engine line-up closer to the introduction date.

Ford is Deliverying Green Motoring AdvancesFord

While there aren’t any models in the current Ford range that meet the Euro 6 emissions standards, work is going on behind the scenes to meet the September 2015 deadline. The latest 1.5-litre TDCi engine that will be going into the facelifted Focus and new Mondeo later this year will meet the standards, as will the upcoming 2.0-litre TDCi engine that goes by the codename Panther. Over time, the 1.5-litre TDCi engine will replace the larger 1.6-litre TDCi units right across Ford’s model range, and will be available in a variety of power outputs from 74bhp to 118bhp, including a 104bhp ECOnetic edition. For smaller vehicles in the line-up, Ford will use lean NOx traps as one tactic of meeting the standards, with engine recalibration and other refinements helping to meet the tougher standards. Ford is yet to reveal any technical information on its 2.0-litre TDCi Panther engine family, but it begins production next year at Ford’s Dagenham Diesel Centre in Essex.

Great Wall

The Steed pick-up doesn’t meet the upcoming Euro 6 regulations right now, but is expected to be upgraded in time for when the tougher requirements are introduced.


Today, none of the Honda line-up are Euro 6 compliant, though engineers are working on making the 1.6-litre diesel engine meet the tougher regulations ahead of time. The new standards will mean the death of the 2.2-litre diesel engine in the CR-V, though our sources suggest that a more powerful 1.6-litre diesel engine is on its way to replace it.


The roll out of the first Euro 6 emissions compliant engines begins towards the end of this year, with the mid-sized i30 and large i40 saloon and Tourer expected to be the first recipients. Currently there aren’t any diesel engines in the Hyundai range that meet the standards.


None of the Infiniti range meet the Euro 6 standards, however, there’s no doubt that they will do by the time the deadline passes. Infiniti engineers are playing their cards close to their chest in terms of introduction times, but of course the engine in the Q50 is a Mercedes-Benz sourced engine, and that same engine in the latest C-Class does meet the latest Euro 6 standards, so it’s entirely possible that a switch to the newer engine will mean that the Q50 complies. As for the rest of the range, it’s a Renault-Nissan Alliance 3.0-litre V6 diesel engine under the bonnet, and work will no doubt be ongoing to ensure that the September 2015 deadline is met.


Currently, the D-Max pick-up doesn’t meet the Euro 6 emissions standards, though it’s expected that Isuzu engineers will be working on a solution so that it meets the regulations by the time they become law.

Web_Jaguar Land RoverJaguar Land Rover

There aren’t any models in the current Jaguar, Land Rover and Range Rover ranges that meet the Euro 6 emissions regulations, however, with a brand new engine factory nearing completion in Wolverhampton, West Midlands, this plant will supply a range of in-line 2.0-litre four-cylinder engines to Jaguar and Land Rover products from next year. The first model out of the traps with the new powerplant will be the new XE compact executive saloon, expected to be shown later this year at the Paris motor show, before its arrival in showrooms next year. Also on show at Paris will be the Discovery Sport, the replacement for the Freelander 2, and this vehicle will use the same range of Ingenium engines, and arrive in showrooms during 2014.


Currently none of the model range are Euro 6 compliant, however, the programme of introduction will kick off with the all-new Sorento, set to be unveiled at the Paris motor show in October, and on-sale early next year. The rest of the Kia line-up will receive compliant engines in time for the September 2015 deadline, with models receiving revised engines at facelift time. Like many other manufacturers, Kia will be taking the selective catalyst reduction route to achieve the tougher standards.


Currently the Ghibli and Quattroporte Diesel comply with Euro 5 emissions standards, but from next April, Maserati will adopt revisions to the engines, along with selective catalyst reduction, so that they can meet the tougher Euro 6 emissions standards.


Bravo, almost all of the Mazda line-up already meet the Euro 6 emissions regulations, with all Mazda3, Mazda6 and CX-5 models already meeting the tougher standards. And Mazda engineers have been extremely clever in achieving them without the need for expensive aftertreatment systems. Thanks to a low compression ratio, the 2.2-litre diesel engine doesn’t require either lean NOx traps or selective catalyst reduction. The upcoming 1.5-litre SkyActiv-D diesel engine that will be fitted to the next generation Mazda2 will also be Euro 6 compliant. Just one model in Mazda’s line-up doesn’t meet the Euro 6 emissions regulations for now, and that’s the Mazda5 1.6 Diesel, and that issue will be solved when the model is replaced.


Work has already begun on launching Euro 6 editions of its engines, with the 220 CDI version of the A, B and CLA-Class already compliant. In addition, the new C, GLA and S-Class also meet the tougher standards, while BlueTEC versions of the E-Class, GL-Class and ML-Class do too. All of the BlueTEC models feature selective catalyst reduction to achieve the requirements. Progressively, Mercedes-Benz will launch extra Euro 6 engines so that the entire line-up is compliant ahead of the September 2015 deadline.


Work is ongoing at MG so that the 6 hatchback and Magnette saloon, powered by the 1.9 DTi engine, comply with the Euro 6 regulations ahead of the September 2015 deadline. It isn’t known which route the company will take in achieving the tougher emissions standards.


The new generation MINI Hatch and its five-door sibling already meet the Euro 6 regulations, with the recently updated Countryman and Paceman also meeting the tougher standards. Over time, the remaining models will be replaced by vehicles sitting on the new MINI UKL1 platform, and they will be powered by the latest Euro 6 three and four-cylinder engines found in the new MINI.


There aren’t any models in the current Mitsubishi line-up that meet the standards, however, work is going on so that the engines meet the regulations ahead of the September 2015 deadline.


Currently none of the Nissan line-up meet the Euro 6 regulations, however, the company says that they are committed to meeting the tougher standards, without any compromise to the performance or economy of the vehicle.


Peugeot already have a number of Euro 6 compliant engines in its line-up, that power the 308, 308 SW and 508 BlueHDi models. Progressively, the company will introduce new engines to its model range so that by the September 2015 deadline, all of the range will comply. The tougher regulations are achieved thanks to selective catalyst reduction, using an AdBlue additive.


The brand-new Macan S Diesel is already Euro 6 compliant, and it is expected that the Panamera and Cayenne engines will be uprated so that they meet the more stringent regulations ahead of time. The Macan uses selective catalyst reduction to achieve the standards and it is predicted that the V6 and V8 diesels in the rest of the line-up will adopt it too. A facelift for the Cayenne is on the horizon, and it is likely that the new Euro 6 engines will be ushered in then.

Web_Renault - 6Renault/Dacia

Engineers at Renault are busy updating the diesel engines to meet the latest regulations with the first Euro 6 1.5-litre dCi engine to be seen in the Megane and Scenic ranges. It will then be a gradual replacement programme up to the September 2015 deadline. Diesel Car spoke to Yorick Duchaussoy, project Director in Renault’s Engineering Department who told us that there’s a lot of work going in to ensure that the latest engines meet the Euro 6 standards. In addition to after-treatment technologies to reduce NOx, like LeanNOx traps and selective catalyst reduction, the company is working on reducing CO2, particles and NOx through continual improvement of the diesel particulate filter, and the development of new Energy engines that feature improved internal combustion, reduced friction and overboost. Yorick predicts that a car featuring selective catalyst reduction will cost around €400 (£320) more than a vehicle equipped with a Lean NOx trap, and so that’s why smaller passenger cars are likely to use the Lean NOx trap technology and large cars and commercial vehicles will go down the selective catalyst reduction route.


There aren’t any models in the SEAT line-up that meet the upcoming Euro 6 emissions regulations right now, but the company plans to begin roll-out of the new engines towards the end of the year, so that by mid next year, all models will comply.


With Skoda part of the vast Volkswagen Group family, the company will adopt similar changes as its siblings. So that will mean LeanNOx traps for all of the diesel engines, with a gradual introduction ahead of the deadline. A new Fabia arrives later this year, and this will be one of the first Skoda models to feature Euro 6 ready engines. But for now, none of Skoda’s diesel engine line-up meet the tougher Euro 6 emissions regulations.


None of the models in the current line-up meet the new standards, but work is ongoing to ensure that they hit the September 2015 deadline. SsangYong’s upcoming compact crossover will be Euro 6 compliant when it hits the showrooms next summer.


The innovative Boxer diesel engine is fitted to the XV, Outback and Forester and is expected to be uprated in advance of the September 2015 deadline. A new Outback will arrive here next year, and that will feature a Euro 6 compliant powerplant.


With the Swift diesel now departed from the Suzuki line-up, it’s just the SX4 S-Cross and Grand Vitara that needs to comply with the latest regulations on the diesel front. And with both engines supplied from other manufacturers, Fiat and Renault respectively, it is expected that changes will be made ahead of the deadline so that the vehicles can continue to be sold. For now there’s no news as to the route that will be taken to meet the tougher standards.


Diesel Car spoke to Gerald Killman, Toyota Europe’s President of Powertrain Research and Development. He said “For Diesel, with Euro 6 emission standards coming close to petrol levels for NOx, we are working on technologies like selective catalyst reduction and NOx-storage catalysts, depending on vehicle size”. He went on to say “For hybrids, which are based on petrol engines with the Toyota D4S injection system or port injection, there is no essential hardware change required to fulfil the emission regulation change from Euro 5 to Euro 6. Certification for Euro6 will be aligned with the introduction of facelifts.” The Lexus CT 200h already meets the tougher Euro 6 standards, and the first diesel engine is expected to be revealed early next year.

Web_Vauxhall - 4Vauxhall

The roll-out of Euro 6 engines has already kicked off, with Vauxhall’s new 1.6-litre CDTi unit percolating across the company’s model ranges. An aluminium cylinder block, together with the use of weight saving materials, means that the new unit is 20kg lighter than its predecessor and has been optimised for reduced friction and faster warm up. Progressively replacing the aged 1.7 CDTi engines, as well as high power 1.3-litre CDTi units and lower powered 2.0-litre CDTi powerplants, the Meriva, Astra and Zafira Tourer line-ups already use the new engine. The lighter cars – Meriva and Astra – have the new engines with lean NOx traps, while the Zafira Tourer utilises the powerplant with selective catalyst reduction, with an AdBlue tank. The 134bhp edition arrived first, with 109bhp and 94bhp variations of the same basic engine arriving in showrooms over the next few months. Vauxhall engineers also promise more powerful editions, too, in the future. Across Vauxhall’s engine portfolio, 13 new engines will be launched, both petrol and diesel, replacing 80 per cent of the company’s current engine range. In addition, smoother shifting manual gearboxes are being rolled out across the range, with improvements to the six-speed automatic transmission to improve efficiency, before it is replaced by a brand new eight-speed unit that will enhance fuel economy by three per cent, compared to the outgoing gearbox.

Web_Volkswagen - 4Volkswagen

A significant amount of work has already been done with regards to Euro 6 compliance, with a number of key models already meeting the standards. The Golf GTD was the first diesel model to adopt the latest Euro 6 engine, with the facelifted Polo, Scirocco and Touareg, all due later this year, to be fully compliant with the standards. The Touareg will employ selective catalyst reduction to achieve this, including AdBlue and a blocking catalytic converter designed to reduce ammonia, whereas the majority of the smaller engines meet the regulations thanks to the inclusion of a Lean NOx trap. All but the BlueMotion version of the new Golf SV medium MPV will meet the tougher standards, too, and a revised Jetta, expected to be announced shortly, will follow suit. Volkswagen says that by mid-2015 model year, its entire model range will be Euro 6 compliant. Of course, one of the biggest new cars for Volkswagen is the new Passat saloon and estate that will be shown at the Paris motor show in October, before arriving in UK showrooms around January time. As well as adopting the latest generation Euro 6 1.6 and 2.0-litre TDI engines, there’s a barnstorming 2.0-litre twin-turbocharged diesel engine that packs 237bhp of power and a massive 369lb ft of torque.


Late last year, Volvo announced its latest four-cylinder turbodiesel engine family, initially in 178bhp D4 guise. This unit complies with the latest Euro 6 emissions regulations, featuring selective catalyst reduction to achieve the tougher regulations. The new 1969cc unit will gradually replace Volvo’s entire engine line-up, in time for the September 2015 deadline. The next all-new product to feature the engine will be the company’s new XC90, its flagship off-roader, which arrives in Volvo dealers early next year.

16 Responses

  1. Picked up my 65 plate Yeti 2.0 TDI 01.09.15 but was not told anything about adding any additives to the fuel system. After 301 miles warning light on dash told me to stop driving and refer to Garage as engine might not start. Email sent to Skoda as on site Eng could not remove warning. See you in 4/5 days as Im on holiday. Might have to replace Adblue tank! This is my 5th Skoda and the last!

  2. While it isn’t great that your Skoda dealer didn’t mention that you’ll need to top up with AdBlue, and that something going wrong so early in the car’s life isn’t good, inevitably cars do go wrong, whatever brand, make or model. With so many components making up a car, it only takes one problem to cause an issue. What is important is how your dealer responds to the issue and how they put it right – that will tell you more about whether you should stick with the Skoda brand, or seek out another when it comes to change.

  3. What (if any) are the implications for UK VW Audi tdi vehicles following yesterday’s (18Sept15) U.S. EPA’s recall order for the use of a “defeat device” to evade clean air standards ? How do the Californian regs compare to Euro 6 ? Assume they are tougher.

  4. Picked up a new VW CC 2.0 TDI BMT 177PS on 18.09.15 from showroom. It is not Euro 6 complaint. From what I understand all NEW cars sold after September 1 2015 must be Euro 6 compliant or am I mistaken ? Any advice ?

  5. The regulations state that all cars built after 1st September 2015 must be Euro-6 compliant, so all car factories around the world will now only be churning out Euro-6 cars.

    Car makers have until next June (2016) to sell all their pre-Euro 6 stock, and it is one of those cars that you have bought, which is perfectly legal.

    I think I would be thankful that you don’t have to top up the AdBlue fluid in the SCR system every 6-7,000 miles like it seems that Euro-6 cars have to be.

    Hope this helps in clarifying.

    1. Thanks Ian, you just saved me from a potentially embarrassing discussion with a VW salesman. I can now relax a bit and wait for my imminent communication from VW to offer to remove the “defeat” code in the engine management software. Worried though as I’ve read this may have an impact on fuel economy. If diesel prices stay the way they are currently then the impact shouldn’t be too bad.

  6. My SEAT Sharan latest model with 2 litre 170 diesel rings a bell with Alan Halls experience. Ad blue and engine warning lights came on whilst on holiday. Managed to get back to my SEAT dealer who advised that Ad blue level had never been checked during services as it was not on the VW maintenance schedule. New software had to be installed before the warning lights extinguished. Now the engine warning light has come on again, all this at 17,000 miles. This is a grest MPV which is being undermined by punitive technology which selects limp home mode and stops engine if driven beyond what they guess is a get you home mileage. This is an MPV which could be full of children in the middle of nowhere.

  7. Correction to previous e-mail – Sorry I referred to VW Sharan, should of course be SEAT Alhambra. (Both vehicles are virtually identical in most fundamental aspects)

  8. Hi Mojo

    There’s no indication that the software change will impact your mpg or CO2, as the ‘defeat’ device was concerned with fooling NOx levels on the American test.

    If you’re happy with the way that your car is performing, there’s nothing to say that you ‘have’ to accept the modification offered by Volkswagen. It isn’t as if there is anything dangerous or safety related, so you could wait until you change the car and ask VW to apply the modification then.

  9. I have recently purchased a brand new Great Wall stead and have been very pleased I was recently told by a parts company that the make will no longer be available after 2017 and may well affect dealers numbers!!! Is this true? I

    1. The engine in the Steed isn’t Euro 5 compliant, but we would expect that it would be upgraded in due course, although haven’t had confirmation from Great Wall of that. The Steed hasn’t set the world alight sales wise, so it could be that the investment in upgrading it for the European market may well not be worth the investment.

  10. I too is a fan of clean diesel engine exhaust. But Can someone explain how exactly an SCR can help in diesel engine fuel economy?

  11. The engine can be run at higher combustion temperatures with SCR than without SCR, the higher combustion temperatures improve fuel economy but create more Nox emissions n the exhaust which SCR exhaust gas after-treatment by Adblue is intended to control by converting the Nox to basic nitrogen.
    Of course this theory does not reflect reality, the manufacturers installed SCR systems of limited capability and durability, and limited the on-road operation of the SCR to a narrow window of unrealistic ambient temperatures, hence the many investigations by European and American authorities into on-road emissions and “defeat devices” of Volkswagen, Fiat, Renault diesel cars among others

  12. I have a Range Rover evoque D-Lux registered in June 2015 and affected by ULEZ charge. This car is fitted with DEF/ Add blue to overcome this problem.
    Does this not meet the Euro 6 emission limits?

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