Big can be beautiful 11 November 2015

In his IRTE Conference keynote Professor David Cebon, of Cambridge University, presented a personal and thought provoking perspective on the future for heavy vehicles. Brian Weatherley reports

David Cebon, professor of mechanical engineering at Cambridge University, took an unconventional approach with his IRTE Conference keynote – starting with his conclusions. Focusing squarely on global sustainability, he declared: “If you want to make a difference in freight vehicle technology and operations you’ve got to consider the three ‘p’s – people, planet and prosperity.”

Tackling the last ‘p’ first, he reminded delegates: “When dealing with any kind of system for reducing fuel consumption and emissions [helping the planet], if you can’t get the economics right, it’s never going to be taken up. That’s the prosperity part.” Likewise, under ‘people’, and referring to new technology and vehicles, he continued: “If you can’t get the politicians, the voice of the people, on board, it’s never going to work either.”

With that benchmark rationale, Cebon proceeded to regale conference with a rapid-fire critique of current fuel-saving and emissions-reducing interventions, starting with ‘low-hanging fruit’ including aerodynamics, lower rolling-resistance tyres, weight-savings, improved refrigeration, lighter chassis and more efficient engines. “All of these improvements feature low barriers to adoption,” he confirmed. “The technologies are well known and understood – and all of these interventions are worth adopting. Unfortunately, their benefits in terms of emissions reduction [saving the planet] are relatively small, usually less than 10%.”

That said, ensuring that drivers have bought into your fuel-saving strategy is essential to making anything work well. “Driver training is very important,” stated Cebon. “It’s a low effort way to reduce fuel consumption. If you can get it to stick, you can expect 8—10% of benefits.” Achieving that ‘stickiness’ can be a challenge, though, which is where driver feedback systems, based on telematics, can make a big difference – albeit with slightly elevated cost barriers.

What abut alternative fuels? As more operators consider dual-fuel vehicles, Cebon confirmed that their potential for CO2 savings could be 15%, but followed that up with a serious caveat. “One of the problems with dual-fuel vehicles is methane emissions, due to incomplete combustion. Methane is a potent greenhouse gas so, until the methane slip problem has been sorted out, dual-fuel vehicles will not be better for the environment than conventional diesels.”

Cebon next delivered a pithy verdict on all-electric vehicles. “Electrification has high barriers to implementation, and until we decarbonise the electricity grid, it doesn’t deliver any significant benefit in terms of CO2 emissions.” Praising electric vehicles for their zero tail-pipe emissions fails to take account of CO2 emissions from the power stations needed to generate the electricity that powers them.

Nevertheless, there are possibilities for electric urban delivery vehicles. These have the benefits of low noise and zero NOx and particulates emissions, both of which are good for the local environment. Diesel-electric and hydraulic hybrids do have potential to reduce emissions by 15—20% in stop-start operations, he confirmed, and they are “relatively low barrier technologies, though somewhat expensive”.

Moving on to truck platooning, while acknowledging that the concept has generated media attention, Cebon remained sceptical. “The barriers, in terms of technology, legislation and safety, are immense, while the fuel consumption and emissions benefits are so low that there really should be more careful thought when promoting them. And autonomous vehicles are even worse.”

So what will make more difference to road freight efficiency? Cebon is unequivocally in favour of longer, heavier HGV combinations – high capacity vehicles, or HCVs. “They offer 20—30% reductions in fuel consumption, reductions in the number of drivers needed and in costs. They also bring improvements in productivity and lead to reductions in traffic congestion and road damage.” Putting more freight on a single truck substantially lowers emissions-per-tonne-km, he added. Additionally, in countries where they are in widespread use, HCVs have significantly better safety records than the conventional vehicles they replaced.

What’s stopping their adoption? Returning to his three ‘p’s theme, Cebon insisted that the barriers are entirely political. Illustrating his point with screen grabs from anti-truck campaigning websites, he agreed that the industry has a major PR battle on its hands. “Public opinion over lorries is not great so it’s not surprising that politicians aren’t enthusiastic about higher-capacity vehicles. But the industry needs to start doing something serious about this because it’s one place where it is possible to make a real difference to fuel consumption and hence CO2 emissions.”

But there are other strategies also worth pursuing, he said, citing the need for operators to tackle empty-running more aggressively. “It’s always beneficial to come home full,” said Cebon, “because if you’re empty, you effectively use 70% more fuel per-tonne-km of work done. Compared with anything else to do with fuel consumption, 70% is a really big number.” And this applies to vehicles of all sizes.

If the public and politicians are to embrace HCVs, they’ll need convincing they’re as safe as, if not safer than, existing vehicles. To that end, Cebon presented videos showcasing several technologies developed by Cambridge University’s engineering team that will be essential for HCVs – including a trailer steering system (developed with Tridec in the Netherlands), which overcomes the ‘whip cracking’ effect during sudden lane changes.

Using the same technology, a trailer can also perfectly follow the prime mover’s steering path even to the extent that a double-trailer HCV meets existing UK turning circle regulations. Equally impressive was a hands-off computer-controlled reversing system shown guiding an experimental triple trailer combination in a straight line, then making a lane change while still backing – a task, said Cebon, that is impossible for a human driver.

Cambridge engineers have also been working on ways of speeding up brake reaction times and improving wheel-slip characteristics on HGV brakes. Key to their development is a novel EBS air valve based on a metal blade flexure between two magnets, claimed to open and close brake chamber air circuits 10 times faster than current technology. Cebon’s team has tested prototype valves on an artic at MIRA and demonstrated a 16% improvement in stopping distance. “That’s about five cars that wouldn’t have been sandwiched in an emergency stop on the motorway” declared Cebon.

Switching to vulnerable road users, Cebon next described an automated HGV braking system, also developed at Cambridge. This detects the presence of a cyclist on the nearside, predicts the likelihood of a collision on a left turn and automatically applies the brakes, if necessary. Explaining that the team used data from 19 fatal HGV/cyclist accident investigations to simulate the impact of its development, Cebon asserted: “We think that 15 could have been completely avoided by this system.” A working version has since been created and delegates were treated to a video showing the system in action, automatically stopping a left-turning tipper before it could hit a dummy cyclist.

“I would challenge those at TfL [Transport for London] and CLOCS [Construction Logistics Cycle Safety] to make sure that the technology they are encouraging is proven to prevent accidents and save lives. It is not sufficient that it helps the driver to see in his blind spot: that doesn’t mean it can prevent an accident. The driver has six mirrors and three windows to monitor. He has to be warned in sufficient time to get the brakes on and stop the accident… That’s a much more challenging thing to do.”

Concluding, Cebon told delegates: “Heavy lorries are here to stay, and for environmental and productivity reasons they need to get bigger. More than anything, the industry needs to persuade politicians and tackle political barriers in a coordinated way. While technology can solve vehicle dynamics issues, safety is a critical aspect of public acceptance of heavy vehicles so the industry must focus very heavily on it.”

Brian Weatherley

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