Emissions control
We join UK team putting cars through new, tougher emissions and economy test – and hit the road to see what’s involved
We meet the team checking on new, real-world mpg tests
MOTORING’S biggest conundrum, and often the top gripe for car buyers, is how distant real-world fuel economy figures – and thus emissions – are from what the manufacturers quote. Motorists are disgruntled that their vehicles return nowhere near the efficiency advertised, while makers insist that the figures are for comparison purposes only and aren’t representative.
The issue behind this frustrating situation is the current laboratory-based type-approval test called New European Driving Cycle (NEDC). Based on thought processes from the seventies, this is riddled with loopholes allowing makers to ‘optimise’ economy figures and quote emissions far below those achieved in the real world. And it leaves buyers with little indication of how efficient their new car will actually be.
Thankfully, this is all set to change. From September, two new type-approval tests will gradually replace the NEDC. The Worldwide harmonised Light vehicles Test Procedure (WLTP) will close some of the loopholes manufacturers currently take advantage of during lab testing. Also, for the first time ever, real-world driving will form part of the test process, under the title Real Driving Emissions (RDE). This will have a heavy focus on nitrogen oxide (NOX) emissions, which have caused health concerns in recent years.
But just how realistic is an RDE cycle, and how will it improve transparency for consumers? Auto Express spent a day at Emissions Analytics in Stokenchurch, Bucks, to find out. These experts have2been testing real-world car performance since 2011 using the same Portable Emissions Measurement System (PEMS) that’ll be crucial to the RDE.
This hefty-looking device is strapped to the back of the car being tested. Airtight tubes fit around the exhaust and lead into a flow meter that measures NOX and carbon dioxide (CO ) emissions. These are then analysed by separate devices stored in the car’s boot, and the results are shown on a laptop in real time.
“With this, we can measure all of the tailpipe emissions, as well as observe things such as fuel economy,” explains Steve Hayton, head of European testing at the company. “The PEMS device is the same as the European Commission will use in its type-approval testing. It takes a measurement roughly every second.”
The current NEDC test is limited to only 20 minutes of lab running, but the new RDE section must be for at least 90 minutes on real roads – although it can be longer. All Emissions Analytics tests last up to three-anda-half hours, collecting more than 12,000 individual data points. Once our Nissan Qashqai is kitted out
with the correct tech, we jump aboard alongside senior technician and vehicle tester Femi Idowu, and head out on the road. The official RDE test is split into urban, rural and motorway segments, each of which has to consist of at least 9.94 miles of driving within the speed limits. On motorways, the cars will have to achieve an average speed of at least 60mph for a minimum of five minutes.
On the road, Idowu talks us through his driving style: “We’re trained to drive very consistently, so we can repeat the style of driving in every car we test. But the way we drive is quite normal to everyday driving.” We find ourselves on a rural road with a 60mph limit, and Idowu gradually accelerates to the maximum speed allowed.
Shortly after, an old Reliant Robin slows us down to 40mph, but rather than wait until we reach the small town about a mile ahead, Idowu accelerates and safely overtakes the driver. “There’s no point in sitting behind someone so slow – it won’t be consistent with the test, and in the real world you’d also overtake,” he explains. The test is modelled on average behaviour, and includes a little ‘aggressive’ driving, such as acceleration. It must also meet a cumulative altitude gain to mirror hills and dips found on most roads. These are currently not recorded in the lab-based NEDC.
The only aspect that remains a problem is the weather. While the RDE doesn’t mandate dry testing, a wet, slippery surface can throw off economy by up to 5mpg – and makers would be unlikely to disadvantage themselves by testing
“Even with the Euro 6-compliant diesels, NOX emissions are four to five times higher on average than the existing laws allow” NICK MOLDEN CEO, Emissions Analytics
in damp conditions. Overall, though, Nick Molden, CEO at Emissions Analytics, says the RDE test is what the industry has long been in need of. “It is a substantial improvement over what we have today,” he explains. “The current lab cycle is very gentle, which has led to real-world emissions being on average five times above the legal limit.”
Emissions Analytics data collected from more than 1,300 tests since 2011 in the UK, Germany and US has found economy is 29 per cent lower on RDE than current lab checks, with real-world CO2 up by 41 per cent.
But these higher figures don’t mean that cars will be taxed more heavily from September. The WLTP, which will be brought in alongside RDE, is still lab based, but its results won’t be used immediately as the NEDC is phased out (see panel, right). The RDE will instead be used to officially record NOX emissions and, as the legislation develops, particulate matter figures. With the WLTP closing lab loopholes and real-world driving targeting harmful emissions, manufacturers have some stiff challenges to meet – and only six months to start meeting them.
Molden explains: “Even with the current Euro 6compliant diesels, NOX emissions are four to five times higher on average than the existing laws allow. Some models pollute 20 times the limit. We could see some diesels taken out of production; likely the smaller-sector vehicles. They’re much harder to clean up because the technology needed to do so will cost more.”
Makers are also starting to see the benefit of real-world transparency beyond the RDE’S official NOX safeguarding role – especially in the wake of the VW Group’s emissions scandal. Last year, PSA Peugeot-citroen released real-world figures for 30-plus cars. Using the same PEMS set-up, it’s now publishing real-world data for 1,000 Peugeot, Citroen and DS models.
Despite these positive moves, Molden remains sceptical about the industry. After all, it’s not unusual for brands to exploit weaknesses in emissions legislation – as recent years have shown. “There’s a lot of effort by makers to get extra wiggle room in the new regime,” he says.
Already car makers have been able to push through conformity factors that let them pollute 2.1 times above the legal NOX limit until 2019, and 1.5 times the limit until 2021. Manufacturers are also allowed to run their own tests, as long as they conform to the EU legislation.
Molden argues: “Another issue is data analysis using normalisation tools. If during the test you’ve been too
gentle or too extreme, manufacturers are allowed to use normalisation tools to balance out the results. This could potentially enable them to ‘game’ the system.
“But there should be no reason to over-complicate this test. We’ve seen it before with the current tests, so the simpler the new ones are, with clear rules, the better it will be for motorists. With an overly complicated system, it will be harder for regulators to spot cheating.”
It’s clear the industry is trying to clean up its act at the same time as its emissions. Let’s just hope the new testing cycle will end the frustrations endured by so many drivers, and finally answer this big automotive conundrum.
“We’re trained to drive very consistently, so we can repeat the style in every car. But it’s quite normal to everyday driving” FEMI IDOWU Emissions Analytics “Test is modelled on average behaviour. It must also mirror hills and dips found on most roads”