Why claims of fuel economy improvements are a load of old cobblers…

Car makers claim they’re making big improvements to fuel economy and emissions, but it’s all a load of old cobblers, says Paul Horrell.

ON PRACTICAL MOTORING recently there was a story on the failure of new cars in Australia to improve fuel-economy fast enough to suit the ambitions of environmental group ClimateWorks. The lobbyists said Europe is doing much better.

Well I have bad news for them. Europe might look like it is doing well. But it isn’t at all. Much of the improvement is illusory. By that line of reasoning, I expect Australia is actually going backwards.

Even if you personally don’t care about the climate-change implications of CO2 emissions, you probably do care about the cost of fuelling your car or ute. Note then that for petrol-engined vehicles, CO2 is directly related to fuel consumption. For diesels it’s also proportional, although with a slightly different multiplier.

Indeed, in the official fuel-consumption test the lab-rats don’t even measure fuel consumption – they measure tailpipe gas and work it out from there.

ClimateWorks grumbles: “The improvement in fuel efficiency of new cars in Australia has dropped to its lowest rate over the last 10 years, with improvement of only 1.1 per cent achieved in 2016 compared to an improvement rate of 4.2 per cent in 2006 and 3.7 per cent in 2012.”

European emission levels are officially falling much faster – by about four percent a year up to today. That’s the figure the carmakers and their lobbyists in Europe put about.

But they are talking – how to put this politely? – a load of old cobblers.

You might have heard of the ICCT or International Council on Clean Transportation. It was them who first exposed the VW diesel NOx cheating. the following year they did something else. They looked at how Europe’s real-world fuel economy lined up against the official figures. They also plotted historical trends.

In 2001, the average European test CO2 figure was 170g/km. The ICCT found that in that year, real-world consumption was only about 10 percent worse than the official figure. ‘Official’ being the figure you see in car adverts as well as websites like ours that are more or less obliged to publish it.

By 2015 Europe’s official average was down to 123g/km. Three cheers. Well no cheers actually because the improvement wasn’t really there. The real-world figure was a staggering 40 percent adrift of the official number, which means in fact there has been precious little on-road improvement at all.

The ICCT didn’t just go out and test a few cars and throw out a headline-grabbing conclusion. It gathered data from some statistically significant sources, totalling more than half a million vehicles.

For example it asked fuel-card payment firms that serve company-car drivers. Think about it. They know exactly how much fuel the driver pumps in. And how many km he or she drives. And they know the car. And they can plot this over the whole time the driver keeps the car and is in the same job.

The report also collates test economy figures from reputable consumer road-test publications. Same result. The official figures became, more and more, a fantasy.

ICCT also tracked services where users can go to web sites and input their own measurements of their own car’s consumption. I don’t tend to trust these because generally only the evangelically happy or the terminally grumpy owners will bother, and you can’t be sure how many of each camp there are. But guess what? The increasing divergence showed up there to a very similar extent as those other data sources.

I did my own little data analysis too. In my job I normally keep a car for six months or so as a long-term tester. Could be a tiddler or a luxo-barge, petrol or diesel, any body style. I take what what I’m given, drive for several thousand km, clean it up and hand it back. I always diligently record the fuel I’ve put in.

And sure enough I’ve found that despite the improvement in official number, the consumption has flatlined for two decades. Example of comparable cars might help: in 1995 I ran a Golf VR6, all 2.7 litres and six cylinders. I drove it like a maniac because I was young and there was little speed enforcement in the UK. I got 10.4l/100km.

In 2012 I had a Ford Focus ST. By this time I had a precious two-year-old in a safety seat sitting behind me, and the speed limits had become far more rigidly enforced. I got 9.8l/100km. Scant improvement there. In 2015, I ran a a Mini Clubman Coooper S All4. That did better, but not much: 9.0l/100.

Basically, small petrol cars net me about 7.5l/100km, and have done for two decades. Bigger petrol cars do 9 or 10l/100km. Small diesels around 6, bigger ones maybe 7, towards 8 for mid-size diesel crossovers. I’m currently getting 7.4 out of a Volvo V90 that’s supposed to do 4.9.

However hard I stare at the chart, I can’t see any favourable trend in consumption. That’s over two dozen cars and a million km.

But there is a clear trend for the divergence between the claim and the actuality. Lately they’ve almost all all been drinking at least 50 percent more than they should.

Why? Because manufacturers have to fix the test, or they fail to compete commercially. Their buyers will be taxed more. They themselves will face sanctions.

How do they fix the test? I figured it was all the ways you normally read about that help a lot in the test but little on the road. Think downsized turbo engines with too few cylinders and too many gears (who honestly wants a nine-speed?).

But it’s worse than that. Manufacturers actually cheat, or at least do things you and all would call cheating but are within the rules.

They tape up the air intakes, over-inflate the tyres and heat-harden their rubber, use ‘prototype parts’ (hem hem). They perform the ‘coast down’ test, which establishes rolling resistance before they go on the dynamometer, on a glossy marble surface. Thus so the car slows down more gently, and then and less resistance is plugged into the dyno. They make sure that all the allowed tolerances in the car and the testing machinery are totalled up in a favourable direction. They supply cars to the test with the standard-fit 40-litre fuel tank in the full knowledge that all owners will specify the heavier, no-cost-option 65-litre tank. And many more.

You might hope that the new Worldwide Light Vehicle Testing Procedure (WLTP) will improve matters. Maybe it will for a while. But doubtless they’ve got engineerings working already on fiddles for that one.

They’re not fools. But they are deceivers.

Paul Horrell

Paul Horrell

Paul's working life has been paced out in cars. He began road-testing when the VW Golf was in its second generation. It's now in its eighth. He covers much more than the tyre-smoking part of the road-test landscape. He roots around in the financial machinations of the car corporations and the apparent voodoo of the technologies. Then he clarifies those complications so his general readers – too busy to lodge their heads up the industry's nether regions – get the fast track on what matters and what doesn't. A freelance writer living in London, he usually gets around the city by bicycle, which adds to his (sometimes justified) reputation as a bit green and a bit of a lefty. He's a member of Europe's Car of the Year jury.