Currently reading: VW emissions scandal: what next for Volkswagen?
The future of Volkswagen, diesels and emissions testing have all been discussed at length - these are the key questions that need to be answered

It’s clear there needs to be big change in the coming weeks and months in light of the Volkswagen emissions scandal that has dominated headlines in recent days, but what form that change will come in is not yet clear. These are the crucial questions that will be discussed and addressed as the matter unfolds.

So why did VW cheat the system?

For commercial reasons is the best analysis available now, according to expert sources. Complying fully with the EPA test would have reduced the performance and economy of the Golf, Jetta and Beetle. VW’s models in the US compete in the cut-throat volume market where good fuel economy and performance is vital. Other German rivals that sell diesel cars operate in a more expensive segment where mpg economy figures are not such a barrier to sales.

Can VW’s 2.0 TDI pass the US test?

Experts say yes. The EA189 engine uses a lean NOx trap (LNT) to store oxides of nitrogen, which are then burnt off in a purge cycle. This technology is widely used and works. BMW, for example, one of whose diesel models was singled out as fully compliant in real-world tests in the EU, use an LNT.

Will VW retro-fit cars be affected?

We don’t yet know. However, the cost of recalling models and re-programming them will cost hundreds of millions of dollars. The big question is whether this cost is worth bearing if, as seems likely, US consumers turn their backs on VW diesels.

So what cars will VW sell in the US?

In the short term, it will have to move to a petrol-only line-up, and rip up its entire diesel-based sales strategy. Another option is to rush plug-in hybrid powertrains, which VW badges as GTE, into production in VW’s two main North American plants, in Mexico and Tennessee. However, establishing a supply chain will take at least 18-24 months, according to Cardiff University Business School professor Peter Wells. The technology is still expensive, so VW’s sales will likely suffer. Another option is to build Audis, but their volumes are small in comparison.

What does this mean for diesels in Europe?

The importance of diesel — it was 53% of the EU market last year compared with 3% in the US — suggests lurid ‘death of diesel’ headlines are simplistic, at best. However, diesel is definitely under political pressure and the industry needs to emphasise its strong points much more firmly. Car buyers know their advantages and many will continue to buy diesels.

Are diesels complying with the latest EU6 rules?

As far as we know now, there is no evidence that EU car makers have ‘defeat codes’ to pass EU6. However, it is true that manufacturers have perfected multiple techniques to squeeze the last g/km out of the test, so a tightening of those rules seems wise. The test run by the EPA in the US is much more prescriptive and more difficult to influence by clever test techniques.

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What about petrol?

So far there is no proof that ‘defeat codes’ have been used to boost MPG figures in the petrol EU6 test. The various investigations now underway must clear up this point.

What about problems with NO2 in city centres?

In real-world conditions, many EU6 diesels are not delivering the same mpg and NO2 figures recorded in the test. The test was never intended for this purpose, but it’s what we’ve got now. There is no requirement for in-use testing, except the UK MoT test, for example, which is only intended to weed out worn-out ‘gross polluters’. The EPA does in-service testing, which probably should be built into the EU test. But ironically, there is no US-wide test for cars in-use. It is a state-by-state policy and many, Michigan for example, don’t test.

A new test is coming to clear this up?

Yes – the WLTP — but Autocar understands that it will hardly tighten the regime and is unlikely to have much effect on MPG/CO2/NOx numbers. The international aspect of the VW scandal should speed-up the decisions still to be made about the detail of the test and its introduction date, possibly as far away as 2020. The car industry may well be wise to re-think its strategy, in the light of the scandal, to ensure the new test is robust in real-world driving. Otherwise, political pressure will only continue to cloud the future of diesel.

Read more on the Volkswagen emissions scandal:

Muller announced as new VW Group CEO

How the Volkswagen story unfolded

Reports suggest VW was warned of illegal software 'years ago'

How VW's 'defeat device' works

Prosecutors to investigate Martin Winterkorn

PSA Peugeot Citroën leads calls for tougher emissions test procedures

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LP in Brighton 25 September 2015


The introduction of WLTP (World Light-vehicle Test Programme) as a single global test regime can only be a good thing. But surely the numbers recorded in this test must be significantly different to those recorder in the NEDC test which everyone complains about? Bearing in mind that NEDC has its roots in the old European ECE15 test cycle (which was introduced around half a century ago to measure exhaust pollutants in slow moving town traffic), the new test needs to be a lot more demanding. What we have now, in Europe, is manufacturers designing vehicles to achieve low emissions and good fuel economy in a test which is predominantly low speed / low load. It doesn't matter what happens when a driver cracks open the throttle in real life, because that situation isn't part of the test. Any new test needs to address this, and it matters not that the recorder figures may be a lot different.