NEDC: Fit for purpose?

Will fleets across Europe need a major rethink of their buying policy if the EU adopts the proposed Worldwide Light Vehicle Test Procedure (WLTP) in 2017?

The WLTP test would replace the New European Driving Cycle (NEDC), which is rapidly losing credibility following a series of reports highlighting the discrepancy between the test results and real‐world driving.

The discrepancy is so great that Italian consumer organisation Altroconsumo plans to take Fiat and Volkswagen to court alleging the companies overinflated claims for fuel consumption of the Panda and Golf models.

The claim could apply to nearly every major manufacturer using NEDC tests and it’s hardly surprising that the industry is resisting change since there are severe financial penalties for manufacturers who fail to meet the EU’s average carbon‐dioxide emissions figure.

Consumption gap widens

Research by the International Council on Clean Transportation (ICCT) suggests the gap between claimed and real‐world fuel economy – and therefore emissions – has jumped in 10 years from 10% to 30%.

The ICCT claims that this discrepancy is costing the average European motorist around €450 a year in extra fuel.

Manufacturers deny they manipulate the tests but acknowledge that there is plenty of scope for interpretation, which is something that both ICCT and

T&E believe the worldwide test procedures would eradicate. Carmakers also point out that different driving styles can easily produce a 30% difference in fuel consumption.

The WLTP involves more vigorous acceleration, higher speeds and a different mix of city and constant speed driving which advocates suggest is far more realistic than the gentle acceleration, low speeds and short cycles of the NEDC tests.

Diesel in the spotlight

But the biggest concern for fleet buyers are the numerous tests indicating that pollution from diesel cars is up to 25 times greater than the legal limit with the average car producing seven times more nitrogen oxides (NOx) than the Euro 6 standard. All new cars registered after January 1, 2015 must meet Euro 6.

This is seen as crucial in the argument against diesel since NOx is the fourth largest contributor to the ‘greenhouse gas’ effect of global warming – a far greater cause for concern than carbon dioxide.

Carmakers always knew that meeting Euro 6 would be a challenge, calling for a 50% reduction in NOx from Euro 5. Only one of the 15 cars tested by ICCT met the new limit of 80mg of NOx per kilometer (down from 500mg/km under Euro 3 in 2000) while the worst car produced more than 2,000mg/km.

This contrasts with petrol‐only vehicles, which generally meet the regulated NOx standards, even in real world driving, according to Emissions Analytics.

Lost tax revenues

There is no doubt a discrepancy between official and real figures, whichever data you choose, but it’s not just motorists who are losing out. European governments who have adjusted tax rates to encourage people and companies to buy more efficient, less polluting cars are losing billions in tax revenue. It is estimated the Netherlands alone is losing €3.4bn every year because of the gap between test and real emission figures.

The debate was thrown into sharp focus in November when Hyundai and

Kia were hit by record $300m fines in the USA for misstating fuel economy figures for 1.2m vehicles. The fines were a record $100m penalty under the US Clean Air Act and an estimated $200m forfeit of greenhouse gas emission credits. These are credits the companies build up by selling more fuel‐efficient cars that can be offset against bigger, less fuel efficient – and more profitable – large cars.

Other companies could now find themselves in the firing line. Ford has already admitted that it had overstated the fuel efficiency of some models and has paid compensation to buyers.

But it won’t necessarily mean a wholesale switch to hybrid or electric vehicles.

Recent research (November 2014) by Emissions Analytics showed that the advantage of hybrid vehicles over frugal diesels could often be an illusion, if judged solely on fuel economy.

The company tested two hybrids against eight diesel models and found that non‐hybrid diesels can be more fuel‐efficient than hybrids by a factor of 28.2l/100km.

Diesel ‘not automatic fleet choice’ Companies like GE Capital Fleet Services are predicting that diesel will not be the automatic choice of fleet buyers in 10 years’ time. Part of that change is driven by what the company described as “growing unease” over the effects of diesel on air quality. GE also points to the potential cost to manufacturers of meeting Euro 7 emission standards, expected to come into force from 2020.

And it’s the debate over air quality rather than fuel consumption that is really driving the issue at the moment.

It’s worth pointing out that the European car industry is the world leader in fuel efficiency precisely because of the EU’s efforts to reduce carbon emissions and the level playing field that the industry has operated in.

ICCT carried out its test by measuring emissions over 97 trips and a total of 6,400km and claims it was “the first systematic analysis of the real‐world performance of modern diesel passenger cars, and the most comprehensive profile available of the on‐road behavior of the latest generation of diesel passenger cars.”

Hybrids only part of the solution

Should fleets consider a wholesale switch to hybrid power? Probably not, unless most of the driving is in congested cities, according to data from Emission Analytics who tested more than 30 hybrids in the UK and US.

The company compared two standard hybrids vs eight diesels with engines ranging from 1.5 to 2.2‐litres, generating up to 150bhp, employing two‐wheel drive, with a hatchback, saloon or estate body style.

The results show that while hybrids can deliver good fuel economy in real world driving, they can be eclipsed by up to 10mpg by some non‐hybrid diesels. This is after taking into account any net changes in battery charge levels to make sure the hybrids are not penalised over the test cycle.

For certain driving patterns, however, hybrids still prove the better option.

They suffer much less than their internal combustion equivalents in congested urban driving – on average a 3% penalty compared to 7%. In contrast, by doubling the average rate of acceleration, fuel consumption falls more for hybrids – especially diesel hybrids.

Comparing motorway driving to town driving, all types of vehicle show better fuel consumption on faster routes.

However, the difference between hybrids and ICE vehicles is dramatic – typically because the downsized engines found in the hybrids are less suited to motorway cruising.

“For diesel cars, we have previously found that low speed, stop‐start driving dramatically increases levels of NOx emissions,” says Nick Molden, CEO of Emissions Analytics.

Carbon monoxide emissions are generally higher for petrol‐only vehicles, but still within the regulated values. As a result, petrol hybrids have the benefit over ICE diesels in their effect on air quality, enhanced by the fact that a proportion of urban driving will be on battery with zero emissions.

“Hybrids may deliver good but not best‐in‐class fuel economy, but they are typically the cleanest, and if you are a light‐footed, congested‐town driver, they are ideal,” says Molden.