Good news on heavy vehicle emissions as car sector chokes

The diesel emissions-rigging scandal surrounding Volkswagen (VW), which has wiped more than a third off the company’s share price, has so far shown no signs of spreading to the heavy-duty sector.

The admission by VW that some of its diesel vehicles had been fitted with so-called ‘defeat devices’ – software which would cause them to emit far smaller amounts of nitrogen oxides (NOx) during testing than in real-world conditions, thereby sidestepping emissions limits – could lead to the recall of up to 11 million vehicles worldwide.

Significantly for the road transport industry, some 1.8 million VW light commercial vehicles (LCVs) are reportedly included within that figure, alongside millions of diesel passenger cars manufactured by VW Group subsidiaries Audi, Seat, Skoda and Volkswagen.

Specifics regarding the LCV models involved were unclear at the time of publishing, but there are said to be 79,838 Volkswagen commercial vehicles affected in the UK, and more than 1.1 million cars. VW said it would be contacting affected customers in due course with details of how to get their vehicles corrected.

The scandal broke shortly after the announcement of good news from the Department for Environment, Food & Rural Affairs (Defra), which has said that low levels of NOx emissions from Euro 6 trucks and buses are already having a discernible benefit on air quality in the UK.

Defra estimates that the effect of nitrogen dioxide, an element of NOx, on mortality in the UK is equivalent to 23,500 deaths per year. But the department’s latest air quality plan indicates that, without further legislative action, as many as 35 of the UK’s 43 air quality zones could be compliant with meeting EU limits for nitrogen dioxide within the next five years.

Measures outlined on an area-by-area basis would see all regions except London become compliant by 2020, with compliance for the capital expected by 2025. Currently 38 of the 43 areas exceed the limits, and previous projections had indicated that 28 would still be non-compliant by 2020.

Shifting projections

According to Defra: “The most significant changes impacting on the projection are a revised assessment of the performance of both Euro 5 and Euro 6 light-duty diesel vehicles and a significant drop in the expected emissions from Euro 6 heavy-duty vehicles; early independent evidence has already demonstrated that the newest lorries and buses are emitting significantly less NOx. There are also other factors such as changes in fleet composition.”

The light-duty diesel vehicles (cars and vans), Defra said, “had not delivered the expected emission reductions in real world use.”

The department said: “Diesel light duty vehicles have emitted more in practice than under test conditions. This disparity has meant that up until the introduction of the new Euro 6 standard, the expected improvements in air quality from the introduction of stricter Euro emission standards have not materialised.”

The European Commission had already therefore been formulating plans to replicate positive results in the heavy-duty market with light-duty vehicles, by introducing a new ‘real driving emissions’ test procedure.

‘Tricks of the trade’

Also published last month was a report by campaigning group Transport & Environment (T&E) entitled ‘Don’t Breathe Here’, which claimed that a number of problems with the Euro 6 test cycle for cars and vans allow diesel vehicles producing above-the-limit levels of NOx onto the road.

The report suggests that the test cycle includes slow acceleration compared to real-world performance, and that flexibilities in procedure (or “tricks of the trade” – “most, if not all” of which “are not… strictly illegal,” says the report) can yield improved results: for example, sending vehicles for test stripped of optional equipment to save weight; overinflating tyres; improving aerodynamics by taping over radiator grilles and the cracks around doors and windows; and using special test lubricants to reduce fuel burn.

The report also points out that the particulate filter regeneration process is not included in the emissions test, although vehicles operating in an urban environment may regenerate their filters regularly.

While the recent findings regarding prohibited ‘defeat devices’ to rig emissions testing have so far been limited to Volkswagen and its subsidiaries, questions are sure to be raised concerning the extent to which this practice has contributed to the light-duty sector’s underperformance in real-world emissions. According to the T&E report, which predates the VW revelations, “anecdotal evidence suggests that it is widespread.”

Tim Barlow, senior technical manager for air quality at the Transport Research Laboratory, TRL, told Transport Operator: “The VW situation could have contributed to the poor effect of the later emission standards on light-duty vehicles. However, there could also be other causal factors. Further research in this area is needed to understand why the reductions in the type approval test limits for light-duty vehicles are not being seen at the roadside.”

The heavy-duty factor

There is a historical precedent in the truck sector for the alleged use of ‘defeat devices’. In 1998, seven truck engine manufacturers agreed to a $1 billion settlement (incorporating $83.4 million in penalties, then a record for a breach of environmental law) of allegations by the US Environmental Protection Agency that they had used computer programmes to allow engines to pass NOx emission tests, despite breaching NOx limits on the road.

Heavy truck manufacturers themselves have yet to comment on any potential for the current crisis to affect the sector. But some experts say that an equivalent scandal in the heavy-duty market is unlikely to emerge.

Tim Barlow of TRL added: “Currently all light duty vehicles with a GVW less than 3.5 tonnes are tested in a similar manner – a complete vehicle is tested on a chassis dynamometer (rolling road) driven over a set driving cycle. So, as well as cars, this also includes vans, pickups, minibuses etc.

“The full extent of the problem is not yet known and won’t be until independent research has been conducted. However, it is more likely to affect Euro 5 and Euro 6 vehicles as these vehicles have increasingly stringent NOx emissions limits.

“It is unlikely that the problem could extend to heavy-duty vehicles over 3.5 tonnes as they are tested in a completely different way to light-duty vehicles. Heavy-duty vehicles (HGVs, buses, coaches etc.) test the engine unit (complete with fuel system, engine control system and any emissions control systems) on an engine test bed and over a new world-harmonised transient test cycle.

“Looking forward, we need to move towards a testing model for light-duty vehicles that’s based on real driving emissions, carried out with vehicles operated on normal roads. This should be followed up with in-use compliance testing, whereby a sample of vehicles already in use are tested to check they still comply with the emissions limits. This would identify and prohibit any vehicles fitted with low emission mode switch.”

Real-world results

Euro 6 standards have strengthened the heavy-duty emissions testing regime. A recent Transport for London emissions report states that: “For heavy duty diesel engines, where the approval takes the form of an engine-dynamometer ‘bench’ test, the engine must conform to the required limits over a broader window of speed and load settings.

“This is followed up by a requirement to verify the emissions performance over a period of on-highway driving with portable emissions analysis equipment fitted to the complete vehicle.

“These new measures seem, at this early stage, to be effective in controlling ‘off-cycle emissions’ much more successfully than before. However, they still do not guarantee universal compliance with the standard under all driving conditions.”

TfL has also carried out real-world testing on the capital’s Euro 6 bus fleet, which demonstrated a 95 per cent NOX emissions reduction against their Euro 5 counterparts and correlates with manufacturer testing.

Industry reaction

We spoke to Christopher Snelling, head of national and regional policy and public affairs at the Freight Transport Association, about both the positive news on heavy-duty emissions, and the situation in the light-duty diesel sector.

“All the indications we’ve had from various sources have been that the heavy-duty vehicle market is holding up on Euro 6,” he said.

“Evidence over the last 18 months has indicated that the on-road performance has matched what it’s supposed to be. And that’s real-world testing by people interested in the air quality in their local areas – it’s not a question of something being reported by the manufacturer. So that’s very positive.

“Obviously what’s hap-pened in the car market raises questions, and there’ll no doubt be further thorough examination of all manufacturers, of probably all types of vehicles, to make sure they are what they say they are.

“It may also prove an extra impetus for continuing to revise the testing regimes, to ensure they reflect on-the-road performance. Our members as operators want the information they get to be as accurate as possible. They want the information about the emissions of new vehicles to accurately match what they achieve when they use them.”

On early suggestions that some light commercial vehicles were implicated in the emissions scandal, Snelling remarked: “Obviously it would be very concerning if vans are also implicated in this… What we would need is for those vehicles to be identified as clearly as possible, and at some point designated as not compliant with Euro 6. We need information on that as quickly as possible so that people can take the time to react.

“If operators have purchased in good faith because those vehicles have been certified as passing, we don’t want to be the ones penalised by being told we’re now no longer going to be compliant with the legal requirement. Then there would need to be discussions about what arrangements there will be with manufacturers about rectifying that.”

Collateral damage?

Snelling added: “I think there is a danger that, if the Euro standards are discredited politically, then you could see some politicians committing to rash actions that aren’t really justified by the evidence. So, there’s a lot more work for us to do in terms of reminding people about the differences between what we know about truck performance and what’s happened with cars.

“What we don’t want is, just because there’s a problem on the car side, for that to automatically discredit the good work that’s been done on the heavy-duty vehicle side. It’s important not to assume that the car problem affects heavy vehicles or all vans, even if some vans are caught up in this.”

The Transport & Environment report can be read here.

Defra is consulting on its air quality improvement plans until November 6, here.