More LEZs are likely, says FTA

Air pollution from diesel-engined road vehicles was a subject that had been grabbing the headlines in the weeks up to the recent FTA Transport Manager Conference at Chepstow, making a presentation on the subject by the FTA’s climate change policy manager Rachael Dillon very timely.

Those old enough to remember the highly visible air pollution of the 1950s might wonder why it was such an issue now, but Ms Dillon pointed out: “While air quality has improved, so has our understanding of its impact on human health.

“The Client Earth case (in which the government was taken to court by an environmental group for allowing sustained local breaches in EU air quality regulations) has forced the UK Government to address the issue quickly.

“Local authorities are likely to be more aggressive in their introduction of Low Emissions Zones,” she warned. “Defra is putting in a framework for low emission zones, which local authorities in England will be expected to follow if they want an LEZ.

“On existing trends, Wales is expected to be compliant by 2020, apart from a stretch of the A48 in Cardiff, which will have a possible bus improvement scheme.”

A Euro 6-only ultra-low Emissions Zone was to be introduced in the London Congestion Charging Zone.

The good news was that, in spite of whatever might have been going on with car exhaust emissions, “Euro 6 is working for trucks,” and was already having a discernible positive impact on air quality, she said.

Which begged the question why Euro 4 and 5 had had so little impact, given that they too saw heavy vehicles using positive post-combustion measures to reduce the emissions of NOx and PM?

“Euro 4 and 5 proved to be not very effective in the real world,” she said. “They did not bring the expected gains in urban air quality.”

One explanation was that heavy vehicles engaged in a stop-start duty cycle did not get their exhaust aftertreatment systems hot enough to trigger the needed reactions to reduce NOx. The catalysts had to be at at least 200°C. Euro 6 vehicles, with far more sophisticated monitoring installed, had systems that worked better in such conditions.

While the focus on toxic emissions had overridden longer-term concerns about greenhouse gasses, Ms Dillon warned that transport managers working for larger companies should already be well on the road to compliance with the Energy Saving Opportunity Scheme (ESOS), which covers energy used in freight, buildings and industrial activity.

Audits for phase one of ESOS had to be completed by 5 December 2015, with all companies with either 250 or more employees or a turnover of £40 million and a balance sheet exceeding £34 million being in-scope. Companies with a fully up-to-date Energy Management System compliant to ISO 50001 are exempt.

ESOS required companies to measure total energy consumption across transport, buildings and industrial activity, but as far as transport was concerned only fuel purchased by the company needed to be included, and sub-contracted transport was excluded.

Companies were required to conduct appoint a professionally-registered ESOS Lead Assessor to oversee or undertake audits to identify cost-effective energy recommendations, but there was no requirement to actually implement them.

Compliance, whether by energy audit or ISO 50001, had to be reported to the Environment Agency by Saturday 5 December 2015 and signed off by a director with an evidence pack retained.

The penalties for failure to conform are severe. The Environment Agency can impose civil penalties of up to £50,000 for non-compliance.

Staying on the air quality theme, Simon Thorne, fleet development manager at event sponsor Volvo Trucks, gave a presentation on the operational effect of Euro 6.

He pointed out that Euro 6 represented reductions of over 90 per cent in soot and NOx per vehicle since the Euro 1 limit was introduced 21 years ago. Even from Euro 5, particulate matter was reduced by 50 per cent and NOx by 80 per cent, so the benefits of Euro 6 were considerable.

The FTA’s survey of transport managers indicated that 57 per cent of member companies had some Euro 6 vehicles on their fleets and 22 per cent of the vehicle parc operated by FTA survey respondents was Euro 6.

This year’s new truck market was now on course to reach 41,000 new truck registrations in the UK, returning it to the level of 2013 which had been boosted by a large pre-buy from operators seeking to avoid Euro 6.

Given the performance of Euro 6 trucks in service, it seems their concerns might have been partly unfounded: the FTA Transport Managers survey reported that ‘real-world’ fuel consumption was unchanged over previous models, although AdBlue consumption was up from four to five per cent to five to eight per cent of fuel burn.

Mr Thorne pointed out that someone purchasing a Euro 6 truck now was in effect getting a ‘future proof’ vehicle regarding its use in low emissions zones.

Changes – some minor, some major – to truck design had been necessary to accommodate Euro 6. Engines ran hotter, hence the larger grilles on big cabs, while smaller cabs had been raised.

“We raised the cab on the FM by 40 mm for better air flow,” Mr Thorne said. “This necessitates changing to low-profile tyres and/or suspension where cab height is critical. By making these changes where needed we have been able to maintain cab heights to previous specifications on critical applications such as car transporters.”

Other changes included the need to incorporate an exhaust aftertreatment ‘can’ some 300mm longer than on Euro 5 trucks, to accommodate a diesel particulate filter. The greater volume of this component, plus the external temperatures of up to 600°C that it might reach, had necessitated Volvo offering the option of a two-part system (with a vertical SCR box) on tipper chassis.

The additional weight of Euro 6 emissions control systems meant that front tyre capacities were often uprated over Euro 5, while a greater thirst for AdBlue had necessitated making larger AdBlue tanks available than previously.

Less obviously the torque curves of Euro 6 engines had changed: peak torque was now produced over a longer, lower rev band than previously on most engines. Mr Thorne cautioned operators to take this into account when specifying new trucks and not to assume that the ratio that worked well on Euro 5 would continue to do so at Euro 6.

“A higher diff ratio will likely be required,” he said.

While there were little or no changes in operational requirements for heavy trucks on long-distance work other than to ensure that the correct engine oil was used (usually a low-ash, low-viscosity semi-synthetic to the individual manufacturer’s requirement), the same was not true for smaller trucks engaged on multi-drop work.

Here it was essential to train drivers about PM filter regeneration. While trucks with big engines on long-haul sustained high enough exhaust temperatures for the filter to burn off soot deposits as they formed, this was not the case for lighter trucks on multi-drop or urban duties.

“Our lighter trucks have a ‘soot gauge’ on the dashboard, which shows how much the DPF has filled up,” Mr Thorne said. “It fills up on short runs, then empties on longer ones. When the system temperature falls below 220°C, the filter starts to fill up.”

To manage the process, Volvo trucks had a three-position switch in the cab. During normal running this could be left in the automatic regeneration position. If the filter filled beyond a preset limit then the engine would automatically raise exhaust temperatures slightly to initiate the regeneration process.

However, this process could not be relied upon if the truck was travelling less than five km between stops, and for this work the filter switch needed to be in the off position.

In such circumstances the filter would probably start to fill up. Drivers needed to be trained to keep an eye on the gauge and heed dashboard warning lights, as the filter would need to be manually regenerated before the gauge reached the red zone indicating that the filter was choked and would have to be removed for specialist cleaning before the truck could be returned to use.

Manual regeneration involved stopping the truck off the public road and clearing an ‘exclusion zone’ of two metres radius from around the exhaust outlet of flammable materials. People and animals should not be allowed into the zone while the regeneration process took place.

The truck needed to be allowed to idle with the switch in the manual position. Tickover speed and engine temperature would rise as extra fuel was injected to heat the soot deposits and burn them off. The process would burn some 3-4 litres of fuel and take about 30 minutes, after which normal running could be resumed.

Mr Thorne said that this process was best carried out in the home depot at the end of a driving shift with the tachograph switched to ‘other work’.

Operation experience had show that only 17 per cent of filter regeneration needed to be done by the manual process, Mr Thorne said.

Irrespective of this process, DPFs on trucks of all types required periodic cleaning or replacement to remove hard ash and metallic deposits. This involved removing the filter and it being heated overnight to temperatures of 800°C in controlled conditions. The filter would be checked for cleanliness and effectiveness before being refitted.

“This process is required every three to five years,” Mr Thorne reported. “If waiting for the filter to be cleaned is inconvenient for the operator, then the old filter can either be exchanged for a cleaned used one or replaced with a new component. Whichever option is preferred can be included in the cost of a Volvo R&M contract.”

Mr Thorne emphasised that the Euro 6 trucks monitored themselves to ensure that Euro 6 limits were adhered to. If warnings about system failures or diminishing levels of AdBlue were ignored then the truck would derate available torque, limit its road speed to 20 km/h and ultimately refuse to start after the engine stopped.

This underlined the importance of training drivers in the meaning of the various dashboard warning lamps and ensuring that they understood the importance of filling up the AdBlue tank correctly.