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Fuel economy testing: What is WLTP and how does it work?

Take a look at the new rules, and what they mean for carmakers in Australia.


From September 2018, the World harmonised Light vehicle Testing Procedure (WLTP), a completely overhauled set of fuel consumption and emissions testing rules designed to replace the New European Driving Cycle (NEDC) test, will come into force. By then, only WLTP-homologated cars will be allowed for sale in Europe.

The new testing process, a focus point for manufacturers for some time now, is at last having clear impact on European markets – and other regions that take cars from Europe, including Australia. In the coming months, the ripples will only continue to spread.

Here's a look at what the new test entails, what it means for car manufacturers and, more specifically, the impact it'll have on the Australian market.

NOTE: This story was first published in 2018



How the new test works

As a replacement for the derided New European Drive Cycle, conceived in the 1980s, WLTP has been designed with input from European manufacturers. It relies heavily on data taken from real-world drive cycles to more accurately represent, you know, real-world drive cycles.

At 30 minutes, the new drive cycle is 50 per cent longer than the NEDC, and the 23.35km route is 12.25km longer than before. During a normal test cycle, cars are driven at low (up to 60km/h), medium (up to 80km/h), high (up 100km/h) and very high (beyond 130km/h) speeds.

As a result of the new speed cycles, the overall average speed on the test is 46km/h instead of 34km/h.

Unlike before, mathematical models are used to determine the difference between cars with unique specifications. That means big wheels, spoilers or heavy add-ons like a sunroof will also have an impact on fuel emissions. Maybe that 22-inch rubber and the panoramic sunroof weren't such a good idea after all.

Hybrid cars will be cycled with and without a full battery, for a more accurate CO2 reading in the real world. After all, owners don't always charge their plug-in hybrids before driving them, so recording both internal-combustion and electric-boosted CO2 figures makes sense.

When it comes into force

The rollout to WLTP actually kicked off in September 2017, at which point the European Union started testing under its new cycle.

Car companies are already using the figures in their official materials, although some still quote NEDC numbers, and any vehicle registered from the start of September 2018 needs a WLTP rating.

That said, there are some exceptions for unsold cars reaching the end of their product cycle. Manufacturers don't have to dump/burn/push off a cliff any cars developed for older test regimes and emissions rules.

WLTP fuel consumption test process (v NEDC)NEDC (old method)WLTP (new method)
Cycle time20 minutes30 minutes
Cycle distance11 kilometres (6.83 miles)23.25 kilometres (14.44 miles)
Driving2 phases: urban driving 66% / extra-urban driving 34%.4 phases: urban driving 52% / extra-urban driving 48%.
Average speed34 km/h (21.12mph)46.5 km/h (28.89mph)
Maximum speed120 km/h (74.56mph)131 km/h (81.39mph)
Influence of
optional equipment
The options and their impact on regulated emissions
(CO, HC, NOx, Particles) and
consumption expressed in CO2 are not taken into account.
Options and their impact on regulated emissions
(CO, HC, NOx, Particles) and
consumption expressed in CO2 are taken into account.
Gears
(manual gearbox)
Pre-determined and fixed gear shiftsGear changes determined according to vehicle characteristics
Temperature testingMeasurements taken at temperatures between 20 and 30°CMeasurements taken at 23°C, then at 14°C for CO2 emissions

But it only applies to Europe, right?

Yes, sort of. Although it's only a legal requirement in Europe, car manufacturers are already adjusting their global line-ups to suit the new protocol.

That's because, under the new protocol, it's more difficult for cars to meet Euro 6.2 emissions regulations. The cycle is more strenuous, and the conditions different, meaning vehicles that might have once snuck beneath CO2 emissions targets now fall foul of those same benchmarks.

Other cars need new particulate filters to meet Euro 6.2 emissions on the new test. That means the manufacture of some models is being "rationalised" to make room for the required production and tooling changes.


What's changing in cars?

A PSA Groupe spokesperson helped us out with this one, explaining what is changing in the PureTech engines used in Peugeot and Citroen vehicles overseas. The changes are summarised below.

  • Petrol engines will get a particulate filter, to cut down on particulate emissions. Peugeot claims a 'filtration effectiveness' of over 75 per cent
  • More advanced emissions reduction systems thanks to more thermally-resistant materials, better exhaust temperature management and new catalytic technology
  • A new-generation oxygen sensor for more precise control of the air/fuel mixture in the cylinder and, as a result, 'optimised' combustion

According to the PSA spokesperson, drivers won't notice the difference between cars with a particulate filter and those without. The filtration system itself is different to those in diesel cars, although it fulfils a similar role.

Where diesel cars need to actively burn the soot collected in their filters (every 600 to 1000km) actively, the "regeneration of a filter in essence is continuous", or passive.

The net result of all of this is, hopefully, cars that more closely match their claimed fuel use figures in the real world.


Is Australia affected by WLTP?

Sure is! Currently in Australia, we certify cars using ADR 79/04 for fuel economy and emissions, but European manufacturers don't design their cars for those rules. Although we won't necessarily get the new, WLTP compliant engines, there'll still be repercussions Down Under.

There are two direct outcomes for our market:

  • Part 1: European carmakers will have to shuffle their line-ups because of changing production schedules
  • Part 2: The fuel standards debate in Australia is going to intensify over the coming weeks, months and years

 

Fuel standards debate intensifies

Talk about fuel standards in Australia has raged for years now, with manufacturers pushing for 'best practice' standards from Europe. Our current fuel sits in between 'sub-par' and 'third-world' in quality, especially when it comes sulphur content.

WLTP and tightening Euro 6+ emissions standards are forcing manufacturers to make their engines cleverer, with emissions-cutting tech like particulate filters becoming commonplace. Problem is, they don't necessarily work with our fuel.

Where rules in Europe limit the sulphur content in petrol to 10 parts-per-million (ppm), current Australian regulations allow 50ppm in premium and 150ppm in regular unleaded.

A report from ClimateWorks, an independent body aiming to inform the transition to zero-emissions motoring, says the push to higher quality fuel will open the door for "more advanced vehicle technologies with better emission control systems and more fuel-efficient engines" Down Under.

There's no guarantee that 'best practice' will be the practice we actually adopt. A report – there are lots of them in the world of politics – from the Ministerial Forum on Vehicle Emissions laid out three options for the future of fuel in Australia, having eliminated a number based on feedback from the public.

Three separate measures are up for discussion:

  • Adopting Euro 6 emissions standards
  • Revising fuel economy rules
  • Bringing our fuel quality into line with "best practice international fuel standards"

The first proposed path, dubbed Option B, would see 91RON fuel removed from sale as 95RON with 10ppm sulphur becomes the base option at Aussie fuel forecourts.

A 35 per cent cap on 'aromatics' in fuel would also be added. These conditions are carried over into Option C, except 91RON fuel with a 10ppm sulphur cap would be retained.

Finally, the third suggested course of action puts a 10ppm sulphur cap on all fuel, with no further changes to our current standards.


What does the industry want?

The 'industry' is made up of many different bodies, people and companies, each with competing interests, but the Federal Chamber of Automotive Industries (FCAI) is a good place to look for an all-around view of how the wider motoring industry feels. Horst von Sanden, Mercedes-Benz CEO in Australia, has recently taken over as president, and used his first speech to call for improvements in fuel standards.

"We need higher quality fuels, as we cannot achieve lower emission outcomes purely on engine management technology, we need fuel of First World Quality to get a First World emissions outcome," he told the crowd.

Tony Weber, the body's chief executive, was more specific. Speaking with CarAdvice about the Ministerial Forum on Vehicle Emissions report earlier this year, he said an aggressive push to high-quality fuel is "what is needed to drive engines today, and in the future".

"Our preferred option would be Option B," Weber told us, calling for 91RON to be removed from sale and replaced with 95RON with 10ppm sulphur.

"It provides quality fuel with 10ppm sulphur and 35 per cent aromatics, which is what is needed to drive engines and today and the future. If we are going to be serious in the country about environmental change, that's the fuel we need," he elaborated, before describing Option F as "not sufficient" for the future.

"We need certainty around these issues so the best products can be brought to Australia with clarity around what is the policy environment in which they will be sold."

Speaking with media at a briefing in Sydney, Volkswagen Australia managing director, Michael Bartsch, told journalists the switch to low-sulphur fuel is as significant as the move from leaded to unleaded.

"We’re becoming outsiders," Bartsch argued, in a long-winded conversation about local fuel standards. "It won’t be long before vehicles are going to have to be produced purely for these really poor sulphur content countries," he said.

The outspoken executive argues our current fuel simply doesn't support the emissions-cutting technology becoming prevalent on European engines, potentially turning us into a "dumping ground" for outdated powertrains. He also suggested our non-compliance with EU standards could cost the average consumer.

"If we don’t move with the time, then ultimately it will become dearer here – it will become dearer from a couple of points of view," he said.

"There’s always an opportunity cost when you don’t get real choice, so we’re going to lose choice here in Australia, and diversity in range."

He later elaborated, arguing Aussies will "start getting lower common denominator products and... we’ll start paying more for the cars, because they’ll start doing special testing and special engine runs" for our market.

By Scott Collie


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